bims-tucedo Biomed News
on Tumor cell dormancy
Issue of 2020‒04‒05
thirty-five papers selected by
Isabel Puig Borreil
Vall d’Hebron Institute of Oncology


  1. Cell Stem Cell. 2020 Apr 02. pii: S1934-5909(20)30099-0. [Epub ahead of print]26(4): 469-471
    Ganesh K.
      In this issue of Cell Stem Cell, Fumagalli et al. (2020) employ intravital microscopy of colorectal cancer organoid xenografts to investigate the cell of origin of metastases. While tumor-initiating cells are Lgr5+, most disseminated cancer cells are Lgr5- and seed liver metastases in which Lgr5+ cells then appear, showing that bidirectional plasticity of phenotypic states drives metastasis.
    DOI:  https://doi.org/10.1016/j.stem.2020.03.007
  2. Oncogene. 2020 Mar 30.
    Chandrashekar DS, Chakravarthi BVSK, Robinson AD, Anderson JC, Agarwal S, Balasubramanya SAH, Eich ML, Bajpai AK, Davuluri S, Guru MS, Guru AS, Naik G, Della Manna DL, Acharya KK, Carskadon S, Manne U, Crossman DK, Ferguson JE, Grizzle WE, Palanisamy N, Willey CD, Crowley MR, Netto GJ, Yang ES, Varambally S, Sonpavde G.
      Muscle-invasive bladder carcinomas (MIBCs) are aggressive genitourinary malignancies. Metastatic urothelial carcinoma of the bladder is generally incurable by current chemotherapy and leads to early mortality. Recent studies have identified molecular subtypes of MIBCs with different sensitivities to frontline therapy, suggesting tumor heterogeneity. We have performed multi-omic profiling of the kinome in bladder cancer patients with the goal of identify therapeutic targets. Our analyses revealed amplification, overexpression, and elevated kinase activity of P21 (RAC1) activated kinase 4 (PAK4) in a subset of Bladder cancer (BLCA). Using bladder cancer cells, we confirmed the role of PAK4 in BLCA cell proliferation and invasion. Furthermore, we observed that a PAK4 inhibitor was effective in curtailing growth of BLCA cells. Transcriptomic analyses identified elevated expression of another kinase, protein tyrosine kinase 6 (PTK6), upon treatment with a PAK4 inhibitor and RNA interference of PAK4. Treatment with a combination of kinase inhibitors (vandetanib and dasatinib) showed enhanced sensitivity compared with either drug alone. Thus, PAK4 may be therapeutically actionable for a subset of MIBC patients with amplified and/or overexpressed PAK4 in their tumors. Our results also indicate that combined inhibition of PAK4 and PTK6 may overcome resistance to PAK4. These observations warrant clinical investigations with selected BLCA patients.
    DOI:  https://doi.org/10.1038/s41388-020-1275-7
  3. Mol Cancer Res. 2020 Apr 03. pii: molcanres.1082.2019. [Epub ahead of print]
    Kastrati I, Joosten SEP, Semina SE, Alejo LH, Brovkovych SD, Stender JD, Horlings HM, Kok M, Alarid ET, Greene GL, Linn SC, Zwart W, Frasor J.
      The purpose of this study was to identify critical pathways promoting survival of tamoxifen-tolerant, estrogen receptor α positive (ER+) breast cancer cells, which contribute to therapy resistance and disease recurrence. Gene expression profiling and pathway analysis was performed in ER+ breast tumors of patients before and after neo-adjuvant tamoxifen treatment and demonstrated activation of the NFκB pathway and an enrichment of EMT/stemness features. Exposure of ER+ breast cancer cell lines to tamoxifen, in vitro and in vivo, gives rise to a tamoxifen-tolerant population with similar NFκB activity and EMT/stemness characteristics. Small molecule inhibitors and CRISPR/Cas9 knock out were used to assess the role of the nuclear factor κB (NFκB) pathway and demonstrated that survival of tamoxifen-tolerant cells requires NFκB activity. Moreover, this pathway was essential for tumor recurrence following tamoxifen withdrawal. These findings establish that elevated NFκB activity is observed in breast cancer cell lines under selective pressure with tamoxifen in vitro and in vivo, as well as in patient tumors treated with neo-adjuvant tamoxifen therapy. This pathway is essential for survival and regrowth of tamoxifen-tolerant cells, and, as such, NFκB inhibition offers a promising approach to prevent recurrence of ER+ tumors following tamoxifen exposure. Implications: Understanding initial changes that enable survival of tamoxifen-tolerant cells, as mediated by NFκB pathway, may translate into therapeutic interventions to prevent resistance and relapse, which remain major causes of breast cancer lethality.
    DOI:  https://doi.org/10.1158/1541-7786.MCR-19-1082
  4. Oncogene. 2020 Apr 01.
    Tian Q, Yuan P, Quan C, Li M, Xiao J, Zhang L, Lu H, Ma T, Zou L, Wang F, Xue P, Ni X, Wang W, Liu L, Wang Z, Zhu F, Duan Q.
      Branched-chain α-keto acid dehydrogenase kinase (BCKDK), the key enzyme of branched-chain amino acids (BCAAs) metabolism, has been reported to promote colorectal cancer (CRC) tumorigenesis by upregulating the MEK-ERK signaling pathway. However, the profile of BCKDK in metastatic colorectal cancer (mCRC) remains unknown. Here, we report a novel role of BCKDK in mCRC. BCKDK is upregulated in CRC tissues. Increased BCKDK expression was associated with metastasis and poor clinical prognosis in CRC patients. Knockdown of BCKDK decreased CRC cell migration and invasion ex vivo, and lung metastasis in vivo. BCKDK promoted the epithelial mesenchymal transition (EMT) program, by decreasing the expression of E-cadherin, epithelial marker, and increasing the expression of N-cadherin and Vimentin, which are mesenchymal markers. Moreover, BCKDK-knockdown experiments in combination with phosphoproteomics analysis revealed the potent role of BCKDK in modulating multiple signal transduction pathways, including EMT and metastasis. Src phosphorylated BCKDK at the tyrosine 246 (Y246) site in vitro and ex vivo. Knockdown and knockout of Src downregulated the phosphorylation of BCKDK. Importantly, phosphorylation of BCKDK by Src enhanced the activity and stability of BCKDK, thereby promoting the migration, invasion, and EMT of CRC cells. In summary, the identification of BCKDK as a novel prometastatic factor in human CRC will be beneficial for further diagnostic biomarker studies and suggests novel targeting opportunities.
    DOI:  https://doi.org/10.1038/s41388-020-1262-z
  5. Nat Commun. 2020 Mar 27. 11(1): 1578
    Zuo H, Yang D, Yang Q, Tang H, Fu YX, Wan Y.
      PARP1 and PARP2 dual inhibitors, such as olaparib, have been recently FDA approved for the treatment of advanced breast and ovarian cancers. However, their effects on bone mass and bone metastasis are unknown. Here we show that olaparib increases breast cancer bone metastasis through PARP2, but not PARP1, specifically in the myeloid lineage, but not in the cancer cells. Olaparib treatment or PARP1/2 deletion promotes osteoclast differentiation and bone loss. Intriguingly, myeloid deletion of PARP2, but not PARP1, increases the population of immature myeloid cells in bone marrow, and impairs the expression of chemokines such as CCL3 through enhancing the transcriptional repression by β-catenin. Compromised CCL3 production in turn creates an immune-suppressive milieu by altering T cell subpopulations. Our findings warrant careful examination of current PARP inhibitors on bone metastasis and bone loss, and suggest cotreatment with CCL3, β-catenin inhibitors, anti-RANKL or bisphosphonates as potential combination therapy for PARP inhibitors.
    DOI:  https://doi.org/10.1038/s41467-020-15429-z
  6. Cancer Res. 2020 Apr 03. pii: canres.3260.2019. [Epub ahead of print]
    Verret B, Sourisseau T, Stefanovska B, Mosele F, Tran-Dien A, André F.
      Next-generation sequencing has sparked the exploration of cancer genomes with the aim of discovering the genetic etiology of the disease and proposing rationally designed therapeutic interventions. Driver gene alterations have been comprehensively charted, but the improvement of cancer patient management somewhat lags behind these basic breakthroughs. Recently, large-scale sequencing that focused on metastasis, the main cause of cancer-related deaths, have shed new light on the driving forces at work during disease progression, particularly in breast cancer. Despite a fairly stable pool of driver genetic alterations between early and late disease, a number of therapeutically targetable mutations have been found enriched in metastatic samples. The molecular processes fueling disease progression have been delineated in recent studies and the clonal composition of breast cancer samples can be examined in detail. Here we discuss how these findings may be combined to improve the diagnosis of breast cancer in order to better select patients at risk, and to identify targeted agents to treat advanced diseases and design therapeutic strategies exploiting vulnerabilities of cancer cells rooted in their ability to evolve and drive disease progression.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-19-3260
  7. Cell. 2020 Mar 30. pii: S0092-8674(20)30270-1. [Epub ahead of print]
    Ruscetti M, Morris JP, Mezzadra R, Russell J, Leibold J, Romesser PB, Simon J, Kulick A, Ho YJ, Fennell M, Li J, Norgard RJ, Wilkinson JE, Alonso-Curbelo D, Sridharan R, Heller DA, de Stanchina E, Stanger BZ, Sherr CJ, Lowe SW.
      KRAS mutant pancreatic ductal adenocarcinoma (PDAC) is characterized by a desmoplastic response that promotes hypovascularity, immunosuppression, and resistance to chemo- and immunotherapies. We show that a combination of MEK and CDK4/6 inhibitors that target KRAS-directed oncogenic signaling can suppress PDAC proliferation through induction of retinoblastoma (RB) protein-mediated senescence. In preclinical mouse models of PDAC, this senescence-inducing therapy produces a senescence-associated secretory phenotype (SASP) that includes pro-angiogenic factors that promote tumor vascularization, which in turn enhances drug delivery and efficacy of cytotoxic gemcitabine chemotherapy. In addition, SASP-mediated endothelial cell activation stimulates the accumulation of CD8+ T cells into otherwise immunologically "cold" tumors, sensitizing tumors to PD-1 checkpoint blockade. Therefore, in PDAC models, therapy-induced senescence can establish emergent susceptibilities to otherwise ineffective chemo- and immunotherapies through SASP-dependent effects on the tumor vasculature and immune system.
    Keywords:  T cells; chemotherapy resistance; endothelial cell activation; immunotherapy; pancreatic cancer; senescence; senescence-associated secretory phenotype; targeted therapy; tumor microenvironment; vascular biology
    DOI:  https://doi.org/10.1016/j.cell.2020.03.008
  8. Theranostics. 2020 ;10(9): 4042-4055
    Zhang Z, Yao Y, Yuan Q, Lu C, Zhang X, Yuan J, Hou K, Zhang C, Du Z, Gao X, Chen X.
      Rationale: Bone is the most frequent site for breast cancer metastasis, which accounts for the leading cause of death in advanced breast cancer patients. Serious skeletal-related events (SREs) caused by bone metastasis have a decisive impact on the life expectancy of breast cancer patients, making breast cancer almost incurable. Metastatic breast cancer cell induced pathological osteoclastogenesis is a key driver of bone metastasis and osteolytic bone lesions. We previously reported that gold clusters can prevent inflammation induced osteoclastogenesis and osteolysis in vivo. In this study, we investigated the effects of a BSA-coated gold cluster on metastatic breast cancer-induced osteoclastogenesis in vitro and tumor-induced osteolysis in vivo, and elucidated its possible mechanism. Methods: Breast cancer cell line MDA-MB-231 was used to evaluate the regulatory effects of gold clusters on breast cancer metastasis and tumor induced osteoclastogenesis in vitro. Cell counting kit-8, transwell, wound-healing and colony formation assays were performed to evaluate the effect of gold clusters on proliferation and metastasis of MDA-MB-231 cells. Tartrate-resistant acid phosphatase (TRAP) staining and filamentous-actin rings analysis were used to detect the regulatory effects of gold clusters on MDA-MB-231 cell-conditioned medium (MDA-MB-231 CM) triggered and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in mouse bone marrow-derived mononuclear cells (BMMs). A mouse model of breast cancer bone metastasis was used to evaluate the in vivo activity of the gold cluster on the tumor induced osteolysis. Results: The gold clusters suppressed the migration, invasion and colony formation of MDA-MB-231 cells in a dose-dependent manner in vitro. The gold clusters strongly inhibited both MDA-MB-231 CM triggered and RANKL-induced osteoclast formation from BMMs in vitro. Cell studies indicated that the gold clusters suppressed the expression of osteolysis-related factors in MDA-MB-231 cells and inhibited the subsequent activation of NF-κB pathway in BMMs. Treatment with the clusters at a dose of 10 mg Au/kg.bw significantly reduces the breast cancer cell induced osteolysis in vivo. Conclusion: Therefore, the gold clusters may offer new therapeutic agents for preventing breast cancer bone metastasis and secondary osteolysis to improve patient outcomes.
    Keywords:  Breast cancer bone metastasis; MDA-MB-231; gold clusters; osteoclastogenesis; osteolysis
    DOI:  https://doi.org/10.7150/thno.42218
  9. Mol Cancer Res. 2020 Mar 30. pii: molcanres.0507.2019. [Epub ahead of print]
    Wang Z, Xu C, Diplas BH, Moure CJ, Chen CJ, Chen LH, Du C, Zhu H, Greer PK, Zhang L, He Y, Waitkus MS, Yan H.
      Diffuse intrinsic pontine glioma (DIPG) is an invariably fatal brain tumor occurring predominantly in children. Up to 90% of pediatric DIPGs harbor a somatic heterozygous mutation resulting in the replacement of lysine 27 with methionine (K27M) in genes encoding histone H3.3 (H3F3A, 65%) or H3.1 (HIST1H3B, 25%). Several studies have also identified recurrent truncating mutations in the gene encoding protein phosphatase 1D, PPM1D, in 9-23% of DIPGs. Here, we sought to investigate the therapeutic potential of targeting PPM1D, alone or in combination with inhibitors targeting specific components of DNA damage response (DDR) pathways in patient-derived DIPG cell lines. We found that GSK2830371, an allosteric PPM1D inhibitor, suppressed the proliferation of PPM1D-mutant, but not PPM1D wild-type DIPG cells. We further observed that PPM1D inhibition sensitized PPM1D-mutant DIPG cells to PARP inhibitor (PARPi) treatment. Mechanistically, combined PPM1D and PARP inhibition show synergistic effects on suppressing a p53-dependent RAD51 expression and the formation of RAD51 nuclear foci, possibly leading to impaired homologous recombination (HR)-mediated DNA repair in PPM1D-mutant DIPG cells. Collectively, our findings reveal the potential role of the PPM1D-p53 signaling axis in the regulation of HR-mediated DNA repair and provide preclinical evidence demonstrating that combined inhibition of PPM1D and PARP1/2 may be a promising therapeutic combination for targeting PPM1D-mutant DIPG tumors. Implications: The findings support the use of PARPi in combination with PPM1D inhibition against PPM1D-mutant DIPGs.
    DOI:  https://doi.org/10.1158/1541-7786.MCR-19-0507
  10. J Biol Chem. 2020 Mar 30. pii: jbc.RA120.013090. [Epub ahead of print]
    Salustiano EJ, da Costa KM, Freire-de-Lima L, Mendonça-Previato L, Previato JO.
      Multidrug resistance (MDR) in cancer arises from cross-resistance to structurally and functionally divergent chemotherapeutic drugs. In particular, MDR is characterized by increased expression and activity of ABC superfamily transporters. Sphingolipids are substrates of ABC proteins, for example, in cell signaling, membrane biosynthesis, and inflammation, and their products can favor cancer progression. Glucosylceramide (GlcCer) is a ubiquitous glycosphingolipid (GSL) generated by glucosylceramide synthase, a key regulatory enzyme encoded by the UDP-glucose ceramide glucosyltransferase (UGCG) gene. Stressed cells increase de novo biosynthesis of ceramides, which return to sub-toxic levels after UGCG-mediate incorporation into GlcCer. Given that cancer cells seem to mobilize UGCG and have increased GSL content for ceramide clearance, which ultimately contributes to chemotherapy failure, here we investigated how inhibition of GSL biosynthesis affects the MDR phenotype of chronic myeloid leukemias. We found that MDR is associated with higher UGCG expression and with a complex GSL profile. UGCG inhibition with the ceramide analog EtDO-P4 greatly reduced GSL and monosialotetrahexosylganglioside (GM1) levels, and co-treatment with standard chemotherapeutics sensitized cells to mitochondrial membrane potential loss and apoptosis. ABC subfamily B member 1 (ABCB1) expression was reduced, and ABCC-mediated efflux activity was modulated, by competition with non-glycosylated ceramides. Consistently, inhibition of ABCC-mediated transport reduced the efflux of exogenous C6-ceramide. Overall, UGCG inhibition impaired the malignant glycophenotype of MDR leukemias, which typically overcomes drug resistance through distinct mechanisms. This work sheds light on the involvement of GSL in chemotherapy failure, and its findings suggest that targeted GSL modulation could help manage MDR leukemias.
    Keywords:  active transport; cancer; ceramide; chronic myelogenous leukemia (CML); ganglioside; glycosyltransferase; lipid metabolism; multidrug transporter; multifactorial drug resistance; neoplasia
    DOI:  https://doi.org/10.1074/jbc.RA120.013090
  11. Nat Commun. 2020 Mar 27. 11(1): 1446
    Cresswell GD, Nichol D, Spiteri I, Tari H, Zapata L, Heide T, Maley CC, Magnani L, Schiavon G, Ashworth A, Barry P, Sottoriva A.
      Circulating tumour DNA (ctDNA) allows tracking of the evolution of human cancers at high resolution, overcoming many limitations of tissue biopsies. However, exploiting ctDNA to determine how a patient's cancer is evolving in order to aid clinical decisions remains difficult. This is because ctDNA is a mix of fragmented alleles, and the contribution of different cancer deposits to ctDNA is largely unknown. Profiling ctDNA almost invariably requires prior knowledge of what genomic alterations to track. Here, we leverage on a rapid autopsy programme to demonstrate that unbiased genomic characterisation of several metastatic sites and concomitant ctDNA profiling at whole-genome resolution reveals the extent to which ctDNA is representative of widespread disease. We also present a methylation profiling method that allows tracking evolutionary changes in ctDNA at single-molecule resolution without prior knowledge. These results have critical implications for the use of liquid biopsies to monitor cancer evolution in humans and guide treatment.
    DOI:  https://doi.org/10.1038/s41467-020-15047-9
  12. Proc Natl Acad Sci U S A. 2020 Apr 01. pii: 201910952. [Epub ahead of print]
    Haldar S, Mishra R, Billet S, Thiruvalluvan M, Placencio-Hickok VR, Madhav A, Duong F, Angara B, Agarwal P, Tighiouart M, Posadas EM, Bhowmick NA.
      Stromal-epithelial interactions dictate cancer progression and therapeutic response. Prostate cancer (PCa) cells were identified to secrete greater concentration of mitochondrial DNA (mtDNA) compared to noncancer epithelia. Based on the recognized coevolution of cancer-associated fibroblasts (CAF) with tumor progression, we tested the role of cancer-derived mtDNA in a mechanism of paracrine signaling. We found that prostatic CAF expressed DEC205, which was not expressed by normal tissue-associated fibroblasts. DEC205 is a transmembrane protein that bound mtDNA and contributed to pattern recognition by Toll-like receptor 9 (TLR9). Complement C3 was the dominant gene targeted by TLR9-induced NF-κB signaling in CAF. The subsequent maturation complement C3 maturation to anaphylatoxin C3a was dependent on PCa epithelial inhibition of catalase in CAF. In a syngeneic tissue recombination model of PCa and associated fibroblast, the antagonism of the C3a receptor and the fibroblastic knockout of TLR9 similarly resulted in immune suppression with a significant reduction in tumor progression, compared to saline-treated tumors associated with wild-type prostatic fibroblasts. Interestingly, docetaxel, a common therapy for advanced PCa, further promoted mtDNA secretion in cultured epithelia, mice, and PCa patients. The antiapoptotic signaling downstream of anaphylatoxin C3a signaling in tumor cells contributed to docetaxel resistance. The inhibition of C3a receptor sensitized PCa epithelia to docetaxel in a synergistic manner. Tumor models of human PCa epithelia with CAF expanded similarly in mice in the presence or absence of docetaxel. The combination therapy of docetaxel and C3 receptor antagonist disrupted the mtDNA/C3a paracrine loop and restored docetaxel sensitivity.
    Keywords:  carcinoma-associated fibroblast; docetaxel; mtDNA; prostate cancer
    DOI:  https://doi.org/10.1073/pnas.1910952117
  13. Clin Cancer Res. 2020 Mar 27. pii: clincanres.3324.2019. [Epub ahead of print]
    Gris-Oliver A, Palafox M, Monserrat L, Brasó-Maristany F, Òdena A, Sánchez-Guixé M, Ibrahim YH, Villacampa G, Grueso J, Parés M, Guzman M, Rodriguez O, Bruna A, Hirst CS, Barnicle A, de Bruin EC, Reddy A, Schiavon G, Arribas J, Mills GB, Caldas C, Dienstman R, Prat A, Nuciforo P, Razavi P, Scaltriti M, Turner NC, Saura C, Davies BR, Oliveira M, Serra V.
      PURPOSE: AZD5363/capivasertib is a pan-AKT catalytic inhibitor with promising activity in combination with paclitaxel in triple negative metastatic breast cancer harboring PI3K/AKT-pathway alterations and in estrogen receptor-positive breast cancer in combination with fulvestrant. Here, we aimed to identify response biomarkers and uncover mechanisms of resistance to AZD5363 and its combination with paclitaxel.EXPERIMENTAL DESIGN: Genetic and proteomic markers were analyzed in HER2-negative patient-derived xenografts (PDXs) and patient samples, and correlated to AZD5363 sensitivity as single agent and in combination with paclitaxel.
    RESULTS: Four PDX were derived from patients receiving AZD5363 in the clinic which exhibited concordant treatment response. Mutations in PIK3CA/AKT1 and absence of mTORC1-activating alterations, e.g. in MTOR or TSC1, were associated with sensitivity to AZD5363 monotherapy. Interestingly, excluding PTEN from the composite biomarker increased its accuracy from 64 to 89%. Moreover, resistant PDXs exhibited low baseline pAKT S473 and residual pS6 S235 upon treatment, suggesting that parallel pathways bypass AKT/S6K1 signaling in these models. We identified two mechanisms of acquired resistance to AZD5363: cyclin D1 overexpression and loss of AKT1 p.E17K.
    CONCLUSIONS: This study provides insight into putative predictive biomarkers of response and acquired resistance to AZD5363 in HER2-negative metastatic breast cancer.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-3324
  14. Theranostics. 2020 ;10(9): 4088-4100
    Zhao T, Jin F, Xiao D, Wang H, Huang C, Wang X, Gao S, Liu J, Yang S, Hao J.
      Human interleukin (IL)-37 is a member of the IL-1 family with potent anti-inflammatory and immunosuppressive properties. Previously, it has been reported that IL-37 suppresses tumor growth and progression. However, the roles of IL-37 in pancreatic cancer development and chemo-resistance remain unknown. Methods: Immunohistochemistry was used to analyze the correlation between IL-37 expression and clinicopathological features of pancreatic ductal adenocarcinoma (PDAC). Western-blot and RT-PCR was used to verify the correlation between IL-37 and hypoxia-inducible factor (HIF)-1α. We performed chromatin immunoprecipitation and luciferase assays to validate HIF-1α suppression of IL-37 expression. Moreover, gain- and loss-of-function studies in vitro and in vivo were used to demonstrate the biological function of IL-37 on PDAC development and chemo-resistance. Results: Our results showed that IL-37 expression was remarkably decreased in PDAC tissues when compared to adjacent normal pancreatic tissues. Reduced IL-37 expression in PDACs was associated with increased PDAC histological grade, tumor size, lymph node metastasis and vessel invasion. IL-37 low patients also have remarkably shorter relapse-free and overall survival. Importantly, IL-37 expression was positively correlated with Gemcitabine efficacy. Mechanistically, HIF-1α attenuated IL-37 transcription by binding to the hypoxia response elements (HREs) in IL-37 promoter. Conversely, IL-37 suppressed HIF-1α expression through STAT3 inhibition. Functionally, downregulation of IL-37 in PDAC cells promoted chemo-resistance, migration and progression in vivo and in vitro. Conclusions: Collectively, our data uncovered IL-37/ STAT3/ HIF-1α negative feedback signaling drives Gemcitabine resistance in PDAC.
    Keywords:  Gemcitabine resistance; Hypoxia-inducible factor (HIF) -1α; IL-37; Pancreatic ductal adenocarcinoma
    DOI:  https://doi.org/10.7150/thno.42416
  15. Oncogene. 2020 Apr 02.
    Zhao C, Yang L, Zhou F, Yu Y, Du X, Xiang Y, Li C, Huang X, Xie C, Liu Z, Lin J, Wang L, Liang G, Cui R.
      Pancreatic cancer is one of the world's leading causes of cancer-related death. Activation of STAT3 has been reported as a major contributor in pancreatic cancer tumorigenesis and chemoresistance. However, treatment of advanced pancreatic cancer patients with STAT3 inhibitors often meets drug resistance and heterogeneous response. We found that EGFR activation is a main cause for resistance to STAT3 inhibitors in pancreatic cancer cells, regardless of KRAS mutation status. Mechanistically, inhibition of STAT3 promotes STAT1- and STAT4-mediated TGF-α expression, leading to activation of the EGFR pathway. Combined treatment of pancreatic cancer cells with EGFR and STAT3 inhibitors persistently blocks EGFR and STAT3 signaling, and exerts synergistic antitumor activity both in vitro and in vivo, with or without KRAS mutation. Our results indicate that reciprocal cross-talk between STAT3 and EGFR pathways is a key molecular mechanism leading to resistance in pancreatic cancer cells. Furthermore, the study shows that combined inhibition of both EGFR and STAT3 might overcome drug resistance encountered during treatment with single agent alone. This study suggests an improved therapeutic strategy, through combined treatment with STAT3 and EGFR inhibitors, for pancreatic cancer patients.
    DOI:  https://doi.org/10.1038/s41388-020-1271-y
  16. Mol Cancer. 2020 Mar 30. 19(1): 68
    Jiang MJ, Chen YY, Dai JJ, Gu DN, Mei Z, Liu FR, Huang Q, Tian L.
      BACKGROUND: Tumor repopulation is a major cause of radiotherapy failure. Previous investigations highlighted that dying tumor cells played vital roles in tumor repopulation through promoting proliferation of the residual tumor repopulating cells (TRCs). However, TRCs also suffer DNA damage after radiotherapy, and might undergo mitotic catastrophe under the stimulation of proliferative factors released by dying cells. Hence, we intend to find out how these paradoxical biological processes coordinated to potentiate tumor repopulation after radiotherapy.METHODS: Tumor repopulation models in vitro and in vivo were used for evaluating the therapy response and dissecting underlying mechanisms. RNA-seq was performed to find out the signaling changes and identify the significantly changed miRNAs. qPCR, western blot, IHC, FACS, colony formation assay, etc. were carried out to analyze the molecules and cells.
    RESULTS: Exosomes derived from dying tumor cells induced G1/S arrest and promoted DNA damage response to potentiate survival of TRCs through delivering miR-194-5p, which further modulated E2F3 expression. Moreover, exosomal miR-194-5p alleviated the harmful effects of oncogenic HMGA2 under radiotherapy. After a latent time, dying tumor cells further released a large amount of PGE2 to boost proliferation of the recovered TRCs, and orchestrated the repopulation cascades. Of note, low-dose aspirin was found to suppress pancreatic cancer repopulation upon radiation via inhibiting secretion of exosomes and PGE2.
    CONCLUSION: Exosomal miR-194-5p enhanced DNA damage response in TRCs to potentiate tumor repopulation. Combined use of aspirin and radiotherapy might benefit pancreatic cancer patients.
    Keywords:  Aspirin; DNA damage response; Exosome; Pancreatic cancer; Radiotherapy; Tumor repopulating cell; Tumor repopulation; microRNA
    DOI:  https://doi.org/10.1186/s12943-020-01178-6
  17. Genes Dev. 2020 Apr 02.
    Yue J, Vendramin R, Liu F, Lopez O, Valencia MG, Gomes Dos Santos H, Gaidosh G, Beckedorff F, Blumenthal E, Speroni L, Nimer SD, Marine JC, Shiekhattar R.
      The emergence of drug resistance is a major obstacle for the success of targeted therapy in melanoma. Additionally, conventional chemotherapy has not been effective as drug-resistant cells escape lethal DNA damage effects by inducing growth arrest commonly referred to as cellular dormancy. We present a therapeutic strategy termed "targeted chemotherapy" by depleting protein phosphatase 2A (PP2A) or its inhibition using a small molecule inhibitor (1,10-phenanthroline-5,6-dione [phendione]) in drug-resistant melanoma. Targeted chemotherapy induces the DNA damage response without causing DNA breaks or allowing cellular dormancy. Phendione treatment reduces tumor growth of BRAFV600E-driven melanoma patient-derived xenografts (PDX) and diminishes growth of NRASQ61R-driven melanoma, a cancer with no effective therapy. Remarkably, phendione treatment inhibits the acquisition of resistance to BRAF inhibition in BRAFV600E PDX highlighting its effectiveness in combating the advent of drug resistance.
    Keywords:  DNA damage response; MAP kinase signaling; cellular dormancy; drug resistance; protein phosphatase 2A; small molecule inhibitor
    DOI:  https://doi.org/10.1101/gad.333864.119
  18. Cancer Cell. 2020 Mar 13. pii: S1535-6108(20)30101-X. [Epub ahead of print]
    Zhang Z, Zhou C, Li X, Barnes SD, Deng S, Hoover E, Chen CC, Lee YS, Zhang Y, Wang C, Metang LA, Wu C, Tirado CR, Johnson NA, Wongvipat J, Navrazhina K, Cao Z, Choi D, Huang CH, Linton E, Chen X, Liang Y, Mason CE, de Stanchina E, Abida W, Lujambio A, Li S, Lowe SW, Mendell JT, Malladi VS, Sawyers CL, Mu P.
      Metastatic prostate cancer is characterized by recurrent genomic copy number alterations that are presumed to contribute to resistance to hormone therapy. We identified CHD1 loss as a cause of antiandrogen resistance in an in vivo small hairpin RNA (shRNA) screen of 730 genes deleted in prostate cancer. ATAC-seq and RNA-seq analyses showed that CHD1 loss resulted in global changes in open and closed chromatin with associated transcriptomic changes. Integrative analysis of this data, together with CRISPR-based functional screening, identified four transcription factors (NR3C1, POU3F2, NR2F1, and TBX2) that contribute to antiandrogen resistance, with associated activation of non-luminal lineage programs. Thus, CHD1 loss results in chromatin dysregulation, thereby establishing a state of transcriptional plasticity that enables the emergence of antiandrogen resistance through heterogeneous mechanisms.
    Keywords:  CHD1; NR2F1; NR3C1 (GR); POU3F2 (BRN2); TBX2; antiandrogen resistantce; castration-resistant prostate cancer; chromatin remodeling; lineage plasticity; tumor heterogeneity
    DOI:  https://doi.org/10.1016/j.ccell.2020.03.001
  19. Theranostics. 2020 ;10(9): 3939-3951
    Wu Z, Li S, Tang X, Wang Y, Guo W, Cao G, Chen K, Zhang M, Guan M, Yang D.
      Rationale: Loss of DNA damage repair (DDR) in the tumor is an established hallmark of sensitivity to DNA damaging agents such as chemotherapy. However, there has been scant investigation into gain-of-function alterations of DDR genes in cancer. This study aims to investigate to what extent copy number amplification of DDR genes occurs in cancer, and what are their impacts on tumor genome instability, patient prognosis and therapy outcome. Methods: Retrospective analysis was performed on the clinical, genomics, and pharmacogenomics data from 10,489 tumors, matched peripheral blood samples, and 1,005 cancer cell lines. The key discoveries were verified by an independent patient cohort and experimental validations. Results: This study revealed that 13 of the 80 core DDR genes were significantly amplified and overexpressed across the pan-cancer scale. Tumors harboring DDR gene amplification exhibited decreased global mutation load and mechanism-specific mutation signature scores, suggesting an increased DDR proficiency in the DDR amplified tumors. Clinically, patients with DDR gene amplification showed poor prognosis in multiple cancer types. The most frequent Nibrin (NBN) gene amplification in ovarian cancer tumors was observed in 15 out of 31 independent ovarian cancer patients. NBN overexpression in breast and ovarian cancer cells leads to BRCA1-dependent olaparib resistance by promoting the phosphorylation of ATM-S1981 and homology-dependent recombination efficiency. Finally, integration of the cancer pharmacogenomics database of 37 genome-instability targeting drugs across 505 cancer cell lines revealed significant correlations between DDR gene copy number amplification and DDR drug resistance, suggesting candidate targets for increasing patient treatment response. Principal Conclusions: DDR gene amplification can lead to chemotherapy resistance and poor overall survival by augmenting DDR. These amplified DDR genes may serve as actionable clinical biomarkers for cancer management.
    Keywords:  DNA damage repair; chemotherapy resistance; pharmacogenetics
    DOI:  https://doi.org/10.7150/thno.39341
  20. Theranostics. 2020 ;10(9): 3967-3979
    Meng Q, Liang C, Hua J, Zhang B, Liu J, Zhang Y, Wei M, Yu X, Xu J, Shi S.
      Background: Dysregulated microRNA (miRNA) expression in cancer can act as a key factor that modifies biological processes, including chemoresistance. Our study aimed to identify the miRNAs associated with gemcitabine (GEM) resistance in pancreatic ductal adenocarcinoma (PDAC) and to explore the potential mechanisms. Methods: The miRNA microarray was used to identify miRNAs associated with GEM resistance. Quantitative real-time PCR was used to examine miR-146a-5p expression in paired PDAC and adjacent normal tissues. Bioinformatics analysis, luciferase reporter assays, and chromatin immunoprecipitation assays were used to confirm tumor necrosis factor receptor-associated factor 6 (TRAF6) as a direct target of miR-146a-5p and to explore the potential transcription factor binding and regulation by miR-146a-5p. In vitro and in vivo experiments were performed to investigate the mechanisms. Results: MiR-146a-5p expression was significantly decreased in PDAC tissues compared with adjacent normal tissues, and miR-146a-5p expression correlated with prognosis in PDAC patients. Functional studies indicated that miR-146a-5p suppressed PDAC cell proliferation and sensitized PDAC cells to GEM chemotherapy by targeting the 3'-untranslated region (3'-UTR) of TRAF6. MiR-146a-5p was also observed to downregulate the TRAF6/NF-κB p65/P-gp axis, which regulates PDAC cell growth and chemoresistance. Conclusions: Taken together, the results indicate that the miR-146a-5p/TRAF6/NF-κB p65 axis drives pancreatic chemoresistance by regulating P-gp, suggesting that miR-146a-5p may be utilized as a new therapeutic target and prognostic marker in PDAC patients.
    Keywords:  chemoresistance; microRNA; pancreatic cancer; prognosis
    DOI:  https://doi.org/10.7150/thno.40566
  21. Cancer Discov. 2020 Apr;10(4): 492-494
    Green MR, Neelapu SS.
      In this issue, Singh and colleagues describe a novel tumor-intrinsic mechanism of resistance to chimericantigen receptor (CAR) T-cell therapy targeting CD19 in B-cell malignancies. They show that reduced expression of death receptor genes in the tumors mediates resistance to killing by CAR T cells, leads to progressive CAR T-cell dysfunction, and is associated with unfavorable clinical outcome in patients.See related article by Singh et al., p. 552.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0037
  22. Cancer Discov. 2020 Apr 03.
      In lung cancer, brain metastasis was associated with somatic amplification of MYC, YAP1, or MMP13.
    DOI:  https://doi.org/10.1158/2159-8290.CD-RW2020-049
  23. Oncogene. 2020 Apr 02.
    Lartigue L, Merle C, Lagarde P, Delespaul L, Lesluyes T, Le Guellec S, Pérot G, Leroy L, Coindre JM, Chibon F.
      Cell fusion in tumor progression mostly refers to the merging of a cancer cell with a cell that has migration and immune escape capabilities such as macrophages. Here we show that spontaneous hybrids made from the fusion of transformed mesenchymal cells with partners from the same lineage undergo nonrecurrent large-scale genomic rearrangements, leading to the creation of highly aneuploid cells with novel phenotypic traits, including metastatic spreading capabilities. Moreover, in contrast to their parents, hybrids were the only cells able to recapitulate in vivo all features of human pleomorphic sarcomas, a rare and genetically complex mesenchymal tumor. Hybrid tumors not only displayed specific mesenchymal markers, but also combined a complex genetic profile with a highly metastatic behavior, like their human counterparts. Finally, we provide evidence that patient-derived pleomorphic sarcoma cells are inclined to spontaneous cell fusion. The resulting hybrids also gain in aggressiveness, exhibiting superior growth capacity in mouse models. Altogether, these results indicate that cell fusion has the potential to promote cancer progression by increasing growth and/or metastatic capacities, regardless of the nature of the companion cell. Moreover, such events likely occur upon sarcoma development, paving the way for better understanding of the biology, and aggressiveness of these tumors.
    DOI:  https://doi.org/10.1038/s41388-020-1276-6
  24. Clin Cancer Res. 2020 Mar 27. pii: clincanres.0168.2020. [Epub ahead of print]
    Stopsack KH, Nandakumar S, Wibmer AG, Haywood S, Weg ES, Barnett ES, Kim CJ, Carbone EA, Vasselman SE, Nguyen B, Hullings MA, Scher HI, Morris MJ, Solit DB, Schultz N, Kantoff PW, Abida W.
      BACKGROUND: The genomic underpinning of clinical phenotypes and outcomes in metastatic castration-sensitive prostate cancer is unclear.METHODS: In patients with metastatic castration-sensitive prostate cancer at a tertiary referral center, clinical-grade targeted tumor sequencing was performed to quantify tumor DNA copy number alterations and alterations in predefined oncogenic signaling pathways. Disease volume was classified as high-volume (>=4 bone metastases or visceral metastases) vs. low-volume.
    RESULTS: Among 424 patients (88% white), 213 (50%) had high-volume disease and 211 (50%) had low-volume disease; 275 (65%) had de-novo metastatic disease and 149 (35%) had metastatic recurrence of non-metastatic disease. Rates of castration resistance (adjusted hazard ratio, 1.84; 95% CI, 1.40-2.41) and death (adjusted hazard ratio, 3.71; 95% CI, 2.28-6.02) were higher in high-volume disease. Tumors from high-volume disease had more copy number alterations. The NOTCH, cell cycle, and epigenetic modifiers pathways were the highest-ranking pathways enriched in high-volume disease. De-novo metastatic disease differed from metastatic recurrences in the prevalence of CDK12 alterations but had similar prognosis. Rates of castration resistance differed 1.5-fold to 5-fold according to alterations in AR, SPOP (inverse), and TP53, and the cell cycle, WNT (inverse), and MYC pathways, adjusting for disease volume and other genomic pathways. Overall survival rates differed 2-fold to 4-fold according to AR, SPOP (inverse), WNT (inverse), and cell cycle alterations. PI3K pathway alterations were not associated with prognosis once adjusted for other factors.
    CONCLUSION: This study identified genomic features associated with prognosis in metastatic castration-sensitive disease that may aid in molecular classification and treatment selection.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-20-0168
  25. Clin Cancer Res. 2020 Mar 31. pii: clincanres.4207.2019. [Epub ahead of print]
    Cai QQ, Tian X, Su N, Wang L, Huang WJ, Liu YH, Zhang X, Huang HQ, Lin T, Ma SY, Rao HL, Li M, Liu F, Zhang F, Zhong LY, Liang L, Lan X, Li J, Liao B, Li Z, Tang QL, Liang Q, Shao C, Zhai Q, Cheng RF, Sun Q, Ru K, Gu X, Lin XN, Yi K, Shuang YR, Chen XD, Dong W, Sun C, Sang W, Liu H, Zhu ZG, Rao J, Guo QN, Zhou Y, Meng XL, Zhu Y, Hu CL, Jiang YR, Zhang Y, Gao HY, He WJ, Xia ZJ, Pan XY, Hai L, Li GW, Song LY, Kang T, Xie D.
      PURPOSE: Adults with T-cell lymphoblastic lymphoma (T-LBL) generally benefit from treatment with acute lymphoblastic leukemia (ALL)-like regimens, but approximately 40% will relapse after such treatment. We evaluated the value of CpG methylation in predicting relapse for adults with T-LBL treated with ALL-like regimens.EXPERIMENTAL DESIGN: A total of 549 adults with T-LBL from 27 medical centers were included in the analysis. Using the Illumina Methylation 850K Beadchip, 44 relapse-related CpGs were identified from 49 T-LBL samples by two algorithms, Least Absolute Shrinkage and Selector Operation (LASSO) and Support Vector Machine-Recursive Feature Elimination (SVM-RFE). We built a four-CpG classifier using LASSO Cox regression based on association between the methylation level of CpGs and relapse-free survival (RFS) in the training cohort (n=160).The four-CpG classifier was validated in the internal testing cohort (n=68) and independent validation cohort (n=321) Results: The four-CpG-based classifier discriminated T-LBL patients at high risk of relapse in the training cohort from those at low risk (p<0.001).This classifier also showed good predictive value in the internal testing cohort (p<0.001) and the independent validation cohort(p<0.001). A nomogram incorporating 5 independent prognostic factors including the CpG-based classifier, lactate dehydrogenase levels, ECOG-PS, central nervous system involvement and NOTCH1/FBXW7 status showed a significantly higher predictive accuracy than each single variable. Stratification into different subgroups by the nomogram helped identify the subset of patients who most benefited from more intensive chemotherapy and/or sequential hematopoietic stem cell transplantation.
    CONCLUSIONS: Our four-CpG-based classifier could predict disease relapse in patients with T-LBL, and could be used to guide treatment decision.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-4207
  26. Mol Cancer. 2020 Apr 03. 19(1): 72
    Shen C, Xuan B, Yan T, Ma Y, Xu P, Tian X, Zhang X, Cao Y, Ma D, Zhu X, Zhang Y, Fang JY, Chen H, Hong J.
      BACKGROUND: Epigenetic alterations are involved in various aspects of colorectal carcinogenesis. N6-methyladenosine (m6A) modifications of RNAs are emerging as a new layer of epigenetic regulation. As the most abundant chemical modification of eukaryotic mRNA, m6A is essential for the regulation of mRNA stability, splicing, and translation. Alterations of m6A regulatory genes play important roles in the pathogenesis of a variety of human diseases. However, whether this mRNA modification participates in the glucose metabolism of colorectal cancer (CRC) remains uncharacterized.METHODS: Transcriptome-sequencing and liquid chromatography-tandem mass spectrometry (LC-MS) were performed to evaluate the correlation between m6A modifications and glucose metabolism in CRC. Mass spectrometric metabolomics analysis, in vitro and in vivo experiments were conducted to investigate the effects of METTL3 on CRC glycolysis and tumorigenesis. RNA MeRIP-sequencing, immunoprecipitation and RNA stability assay were used to explore the molecular mechanism of METTL3 in CRC.
    RESULTS: A strong correlation between METTL3 and 18F-FDG uptake was observed in CRC patients from Xuzhou Central Hospital. METTL3 induced-CRC tumorigenesis depends on cell glycolysis in multiple CRC models. Mechanistically, METTL3 directly interacted with the 5'/3'UTR regions of HK2, and the 3'UTR region of SLC2A1 (GLUT1), then further stabilized these two genes and activated the glycolysis pathway. M6A-mediated HK2 and SLC2A1 (GLUT1) stabilization relied on the m6A reader IGF2BP2 or IGF2BP2/3, respectively.
    CONCLUSIONS: METTL3 is a functional and clinical oncogene in CRC. METTL3 stabilizes HK2 and SLC2A1 (GLUT1) expression in CRC through an m6A-IGF2BP2/3- dependent mechanism. Targeting METTL3 and its pathway offer alternative rational therapeutic targets in CRC patients with high glucose metabolism.
    Keywords:  Colorectal cancer; GLUT1; Glycolysis; HK2; METTL3; m6A modification
    DOI:  https://doi.org/10.1186/s12943-020-01190-w
  27. Theranostics. 2020 ;10(9): 4201-4216
    Xu Z, Ma T, Zhou J, Gao W, Li Y, Yu S, Wang Y, Chan FL.
      Enhanced intratumoral androgen biosynthesis and persistent androgen receptor (AR) signaling are key factors responsible for the relapse growth of castration-resistant prostate cancer (CRPC). Residual intraprostatic androgens can be produced by de novo synthesis of androgens from cholesterol or conversion from adrenal androgens by steroidogenic enzymes expressed in prostate cancer cells via different steroidogenic pathways. However, the dysregulation of androgen biosynthetic enzymes in CRPC still remains poorly understood. This study aims to elucidate the role of the nuclear receptor, estrogen-related receptor alpha (ERRα, ESRRA), in the promotion of androgen biosynthesis in CRPC growth. Methods: ERRα expression in CRPC patients was analyzed using Gene Expression Omnibus (GEO) datasets and validated in established CRPC xenograft model. The roles of ERRα in the promotion of castration-resistant growth were elucidated by overexpression and knockdown studies and the intratumoral androgen levels were measured by UPLC-MS/MS. The effect of suppression of ERRα activity in the potentiation of sensitivity to androgen-deprivation was determined using an ERRα inverse agonist. Results: ERRα exhibited an increased expression in metastatic CRPC and CRPC xenograft model, could act to promote castration-resistant growth via direct transactivation of two key androgen synthesis enzymes CYP11A1 and AKR1C3, and hence enhance intraprostatic production of dihydrotestosterone (DHT) and activation of AR signaling in prostate cancer cells. Notably, inhibition of ERRα activity by an inverse agonist XCT790 could reduce the DHT production and suppress AR signaling in prostate cancer cells. Conclusion: Our study reveals a new role of ERRα in the intratumoral androgen biosynthesis in CRPC via its transcriptional control of steroidogenic enzymes, and also provides a novel insight that targeting ERRα could be a potential androgen-deprivation strategy for the management of CRPC.
    Keywords:  AKR1C3; CYP11A1; ERRα; castration resistance; intratumoral steroidogenesis; nuclear receptor; prostate cancer
    DOI:  https://doi.org/10.7150/thno.35589
  28. Oncogene. 2020 Mar 31.
    Ricciardiello F, Gang Y, Palorini R, Li Q, Giampà M, Zhao F, You L, La Ferla B, De Vitto H, Guan W, Gu J, Zhang T, Zhao Y, Chiaradonna F.
      Different evidence has indicated metabolic rewiring as a necessity for pancreatic cancer (PC) growth, invasion, and chemotherapy resistance. A relevant role has been assigned to glucose metabolism. In particular, an enhanced flux through the Hexosamine Biosynthetic Pathway (HBP) has been tightly linked to PC development. Here, we show that enhancement of the HBP, through the upregulation of the enzyme Phosphoacetylglucosamine Mutase 3 (PGM3), is associated with the onset of gemcitabine (GEM) resistance in PC. Indeed, mRNA profiles of GEM sensitive and resistant patient-derived tumor xenografts (PDXs) indicate that PGM3 expression is specifically increased in GEM-resistant PDXs. Of note, PGM3 results also overexpressed in human PC tissues as compared to paired adjacent normal tissues and its higher expression in PC patients is associated with worse median overall survival (OS). Strikingly, genetic or pharmacological PGM3 inhibition reduces PC cell growth, migration, invasion, in vivo tumor growth and enhances GEM sensitivity. Thus, combined treatment between a specific inhibitor of PGM3, named FR054, and GEM results in a potent reduction of xenograft tumor growth without any obvious side effects in normal tissues. Mechanistically, PGM3 inhibition, reducing protein glycosylation, causes a sustained Unfolded Protein Response (UPR), a significant attenuation of the pro-tumorigenic Epidermal Growth Factor Receptor (EGFR)-Akt axis, and finally cell death. In conclusion this study identifies the HBP as a metabolic pathway involved in GEM resistance and provides a strong rationale for a PC therapy addressing the combined treatment with the PGM3 inhibitor and GEM.
    DOI:  https://doi.org/10.1038/s41388-020-1260-1
  29. Ann Oncol. 2020 Feb 20. pii: S0923-7534(20)36055-5. [Epub ahead of print]
    Waks AG, Cohen O, Kochupurakkal B, Kim D, Dunn CE, Buendia Buendia J, Wander S, Helvie K, Lloyd MR, Marini L, Hughes ME, Freeman SS, Ivy SP, Geradts J, Isakoff S, LoRusso P, Adalsteinsson VA, Tolaney SM, Matulonis U, Krop IE, D'Andrea AD, Winer EP, Lin NU, Shapiro GI, Wagle N.
      BACKGROUND: Little is known about mechanisms of resistance to poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy in patients with metastatic breast cancer and BRCA1/2 mutations. Further investigation of resistance in clinical cohorts may point to strategies to prevent or overcome treatment failure.PATIENTS AND METHODS: We obtained tumor biopsies from metastatic breast cancer patients with BRCA1/2 deficiency before and after acquired resistance to PARPi or platinum chemotherapy. Whole exome sequencing was carried out on each tumor, germline DNA, and circulating tumor DNA. Tumors underwent RNA sequencing, and immunohistochemical staining for RAD51 foci on tumor sections was carried out for functional assessment of intact homologous recombination (HR).
    RESULTS: Pre- and post-resistance tumor samples were sequenced from eight patients (four with BRCA1 and four with BRCA2 mutation; four treated with PARPi and four with platinum). Following disease progression on DNA-damaging therapy, four patients (50%) acquired at least one somatic reversion alteration likely to result in functional BRCA1/2 protein detected by tumor or circulating tumor DNA sequencing. Two patients with germline BRCA1 deficiency acquired genomic alterations anticipated to restore HR through increased DNA end resection: loss of TP53BP1 in one patient and amplification of MRE11A in another. RAD51 foci were acquired post-resistance in all patients with genomic reversion, consistent with reconstitution of HR. All patients whose tumors demonstrated RAD51 foci post-resistance were intrinsically resistant to subsequent lines of DNA-damaging therapy.
    CONCLUSIONS: Genomic reversion in BRCA1/2 was the most commonly observed mechanism of resistance, occurring in four of eight patients. Novel sequence alterations leading to increased DNA end resection were seen in two patients, and may be targetable for therapeutic benefit. The presence of RAD51 foci by immunohistochemistry was consistent with BRCA1/2 protein functional status from genomic data and predicted response to later DNA-damaging therapy, supporting RAD51 focus formation as a clinically useful biomarker.
    Keywords:  BRCA1; BRCA2; PARP inhibitor; breast cancer; platinum
    DOI:  https://doi.org/10.1016/j.annonc.2020.02.008
  30. J Clin Invest. 2020 Mar 31. pii: 124037. [Epub ahead of print]
    Salazar Y, Zheng X, Brunn D, Raifer H, Picard FS, Zhang Y, Winter H, Günther S, Weigert A, Weigmann B, Dumoutier L, Renauld JC, Waisman A, Schmall A, Tufman A, Fink L, Brüne B, Bopp T, Grimminger F, Seeger W, Pullamsetti SS, Huber M, Savai R.
      Immune microenvironment plays a critical role in lung cancer control versus progression and metastasis. In this investigation, we explored the impact of tumor-infiltrating-lymphocyte subpopulations on lung cancer biology by studying in vitro co-cultures, in vivo mouse models and human lung cancer tissue. Lymphocyte conditioned media-(CM) induced epithelial-mesenchymal-transition (EMT), and migration in both primary human lung cancer cells and cell lines. Correspondingly, major accumulation of Th9 and Th17 cells was detected in human lung cancer tissue, and correlated with poor survival. Co-culturing lung cancer cells with Th9/Th17 cells or exposing them to the respective-CM induced-EMT in cancer cells and modulated the expression profile of genes implicated in EMT and metastasis. These features were reproduced by the signatory cytokines IL-9 and IL-17, with gene regulatory profiles evoked by these cytokines partly overlapping and partly complementary. Co-injection of Th9 and/or Th17 cells with tumor cells in wildtype, Rag1-/-, Il9r-/- and Il17ra-/- mice altered tumor growth and metastasis. Accordingly, inhibition of IL-9 or IL-17 cytokines by neutralizing antibodies decreased EMT and slowed lung cancer progression and metastasis. In conclusion, Th9 and Th17 lymphocytes induce lung cancer cell EMT, thereby promoting migration, and metastatic spreading and offering for novel therapeutic strategies.
    Keywords:  Cancer; Inflammation; Oncology; T cells
    DOI:  https://doi.org/10.1172/JCI124037
  31. Theranostics. 2020 ;10(9): 4056-4072
    Hu T, Liu H, Liang Z, Wang F, Zhou C, Zheng X, Zhang Y, Song Y, Hu J, He X, Xiao J, King RJ, Wu X, Lan P.
      Rationale: CD47 plays a vital role in the immune escape of tumor cells, but its role in regulating immune-unrelated biological processes such as proliferation and metastasis remains unclear. We seek to explore the immune-independent functions of CD47 in colorectal cancer (CRC). Methods: The expression of CD47 in CRC was determined by immunohistochemistry. The biological effect of CD47 signaling on tumor cell proliferation and metastasis was evaluated in vitro and in vivo. RNA sequencing analysis was performed to identify pivotal signaling pathways modulated by CD47. The interaction between CD47 and ENO1 was verified by co-immunoprecipitation (co-IP). The effect of CD47 on glycolytic metabolites was analyzed by seahorse XF and targeted metabolomics. Results: The expression of CD47 was upregulated and correlated to poor prognosis in CRC patients. Functional assays revealed that CD47 promoted CRC cell growth and metastasis in vitro and in vivo. Our mechanistic investigations demonstrated that CD47 interacted with ENO1 and protected it from ubiquitin-mediated degradation, subsequently promoting glycolytic activity and phosphorylation of ERK in CRC cells. Inhibition of ENO1 diminished CD47-mediated cell growth and migration. Clinically, the combined expression of CD47 and ENO1 provided reliable predictive biomarkers for the prognosis of CRC patients. Conclusions: CD47 is overexpressed in CRC, and its expression is associated with poor prognosis. Through stabilizing ENO1, CD47 enhances the aerobic glycolysis and ERK activity in CRC cells, thereby promoting the progression of CRC. Our studies reveal an unconventional role of CD47, suggesting that targeting the CD47-ENO1 axis may provide a novel therapeutic avenue for CRC.
    Keywords:  CD47; Colorectal Cancer; ENO1; ERK; Glycolysis
    DOI:  https://doi.org/10.7150/thno.40860
  32. Clin Cancer Res. 2020 Mar 31. pii: clincanres.1895.2019. [Epub ahead of print]
    Shattuck-Brandt RL, Chen SC, Murray E, Johnson CA, Crandall H, O'Neal JF, Al-Rohil RN, Nebhan CA, Bharti V, Dahlman KB, Ayers GD, Kelley MC, Kauffman RM, Hooks M, Grau A, Johnson DB, Vilgelm AE, Richmond A.
      PURPOSE: Over 60% of melanoma patients respond to immune checkpoint inhibitor (ICI) therapy, but many subsequently progress on these therapies. Second-line targeted therapy is based on BRAF mutation status, but no available agents are available for NRAS, CDKN2A, PTEN, and TP53 mutations. Over 70% of melanoma tumors have activation of the MAPK pathway due to BRAF or NRAS mutations, while loss or mutation of cdkn2a occurs in ~40% of melanomas, resulting in unregulated MDM2-mediated ubiquitination and degradation of P53. Here we investigated the therapeutic efficacy of over-riding MDM2-mediated degradation of P53 in melanoma with an MDM2 inhibitor that interrupts MDM2 ubiquitination of P53, treating tumor-bearing mice with the MDM2 inhibitor alone or combined with MAPK-targeted therapy.EXPERIMENTAL DESIGN: To characterize the ability of the MDM2 antagonist, KRT-232, to inhibit tumor growth, we established patient-derived xenografts (PDX) from 15 melanoma patients. Mice were treated with KRT-232 or a combination with BRAF and/or MEK inhibitors. Tumor growth, gene mutation status, as well as protein and protein-phosphoprotein changes, were analyzed.
    RESULTS: 100% of the 15 PDX tumors exhibited significant growth inhibition either in response to KRT-232 alone or in combination with BRAF and/or MEK inhibitors. Only BRAFV600wt tumors responded to KRT-232 treatment alone while BRAFV600E/M PDXs exhibited a synergistic response to the combination of KRT-232 and BRAF/MEK inhibitors.
    CONCLUSIONS: KRT-232 is an effective therapy for the treatment of either BRAFwt or PANwt (BRAFwt, NRASwt) TP53WT melanomas. In combination with BRAF and/or MEK inhibitors, KRT-232 may an effective treatment strategy for BRAFV600 mutant tumors.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-1895
  33. Blood. 2020 Mar 13. pii: blood.2019004770. [Epub ahead of print]
    Hasserjian RP, Steensma DP, Graubert TA, Ebert BL.
      Current objectives regarding treatment for acute myeloid leukemia (AML) include achieving complete remission (CR) by clinicopathological criteria followed by interrogation for the presence of minimal/measurable residual disease (MRD) by molecular genetic and/or flow cytometric techniques. While advances in molecular genetic technologies have enabled highly sensitive detection of AML-associated mutations and translocations, determination of MRD is complicated by the fact that many treated patients have persistent clonal hematopoiesis that may not reflect residual AML. Clonal hematopoiesis detected in AML patients in CR includes true residual or early recurrent AML, myelodysplastic syndrome (MDS) or clonal hematopoiesis that is ancestral to the AML, and independent or newly emerging clones of uncertain leukemogenic potential. While the presence of AML-related mutations has been shown to be a harbinger of relapse in multiple studies, the significance of other types of clonal hematopoiesis is less well understood. In patients who undergo allogeneic hematopoietic cell transplantation (HCT), post-HCT clones can be donor-derived and in some cases engender a new myeloid neoplasm that is clonally unrelated to the recipient's original AML. In this article, we discuss the spectrum of clonal hematopoiesis that can be detected in treated AML patients, propose terminology to standardize nomenclature in this setting, and review clinical data and areas of uncertainty among the various type of post-treatment hematopoietic clones.
    DOI:  https://doi.org/10.1182/blood.2019004770