bims-tucedo Biomed News
on Tumor cell dormancy
Issue of 2020‒11‒01
23 papers selected by
Isabel Puig Borreil
Vall d’Hebron Institute of Oncology


  1. Cancer Res. 2020 Oct 28. pii: canres.1976.2020. [Epub ahead of print]
    Wills CA, Liu X, Chen L, Zhao Y, Dower CM, Sundstrom J, Wang HG.
      Although neoadjuvant chemotherapy is a standard component of breast cancer treatment, recent evidence suggests that chemotherapeutic drugs can promote metastasis through poorly-defined mechanisms. Here we utilize xenograft mouse models of triple-negative breast cancer to explore the importance of chemotherapy-induced tumor-derived small extracellular vesicles (sEV) in metastasis. Doxorubicin (DXR) enhanced tumor cell sEV secretion to accelerate pulmonary metastasis by priming the pre-metastatic niche. Proteomic analysis and CRISPR/Cas9 gene editing identified the inflammatory glycoprotein PTX3 enriched in DXR-elicited sEV as a critical regulator of chemotherapy-induced metastasis. Both genetic inhibition of sEV secretion from primary tumors and pharmacologic inhibition of sEV uptake in secondary organs suppressed metastasis following chemotherapy. Taken together, this research uncovers a mechanism of chemotherapy-mediated metastasis by which drug-induced upregulation of sEV secretion and PTX3 protein cargo primes the pre-metastatic niche and suggests that inhibition of either sEV uptake in secondary organs or secretion from primary tumor cells may be promising therapeutic strategies to suppress metastasis.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-1976
  2. Cancer Cell. 2020 Oct 16. pii: S1535-6108(20)30498-0. [Epub ahead of print]
    Chang G, Shi L, Ye Y, Shi H, Zeng L, Tiwary S, Huse JT, Huo L, Ma L, Ma Y, Zhang S, Zhu J, Xie V, Li P, Han L, He C, Huang S.
      Brain metastasis is a major cause of cancer mortality, but its molecular mechanisms are severely understudied. In addition, little is known regarding the role of m6A reader YTHDF3 in human diseases. Here, we show that YTHDF3 overexpression clinically correlates with brain metastases in breast cancer patients. YTHDF3 promotes cancer cell interactions with brain endothelial cells and astrocytes, blood-brain barrier extravasation, angiogenesis, and outgrow. Mechanistically, YTHDF3 enhances the translation of m6A-enriched transcripts for ST6GALNAC5, GJA1, and EGFR, all associated with brain metastasis. Furthermore, overexpression of YTHDF3 in brain metastases is attributed to increased gene copy number and the autoregulation of YTHDF3 cap-independent translation by binding to m6A residues within its own 5' UTR. Our work uncovers an essential role of YTHDF3 in controlling the interaction between cancer cells and brain microenvironment, thereby inducing brain metastatic competence.
    Keywords:  YTHDF3; brain metastasis; epigenetic regulation; gene amplification; m(6)A RNA methylation
    DOI:  https://doi.org/10.1016/j.ccell.2020.10.004
  3. Mol Aspects Med. 2020 Oct 26. pii: S0098-2997(20)30123-0. [Epub ahead of print] 100921
    Wang Y, Gao W, Li Y, Chow ST, Xie W, Zhang X, Zhou J, Chan FL.
      It is well-established that both the initial and advanced growth of prostate cancer depends critically on androgens and thus on the activated androgen receptor (AR) -mediated signaling pathway. The unique hormone-dependent feature of prostate cancer forms the biological basis of hormone or androgen-deprivation therapy (ADT) that aims to suppress the AR signaling by androgen depletion or AR antagonists. ADT still remains the mainstay treatment option for locally advanced or metastatic prostate cancer. However, most patients upon ADT will inevitably develop therapy-resistance and progress to relapse in the form of castration-resistant disease (castration-resistant prostate cancer or CRPC) or even a more aggressive androgen-independent subtype (therapy-related neuroendocrine prostate cancer or NEPC). Recent advances show that besides AR, some ligand-independent members of nuclear receptor superfamily-designated as orphan nuclear receptors (ONRs), as their endogenous physiological ligands are either absent or not yet identified to date, also play significant roles in the growth regulation of prostate cancer via multiple AR-dependent or -independent (AR-bypass) pathways or mechanisms. In this review, we summarize the recent progress in the newly elucidated roles of ONRs in prostate cancer, with a focus on their interplay in the AR-dependent pathways (intratumoral androgen biosynthesis and suppression of AR signaling) and AR-independent pathways or cellular processes (hypoxia, oncogene- or tumor suppressor-induced senescence, apoptosis and regulation of prostate cancer stem cells). These ONRs with their newly characterized roles not only can serve as novel biomarkers but also as potential therapeutic targets for management of advanced prostate cancer.
    Keywords:  Androgen receptor; Castration-resistance; Orphan nuclear receptors; Prostate cancer
    DOI:  https://doi.org/10.1016/j.mam.2020.100921
  4. Nat Commun. 2020 10 29. 11(1): 5463
    Tripathi R, Liu Z, Jain A, Lyon A, Meeks C, Richards D, Liu J, He D, Wang C, Nespi M, Rymar A, Wang P, Wilson M, Plattner R.
      Metastatic melanoma remains an incurable disease for many patients due to the limited success of targeted and immunotherapies. BRAF and MEK inhibitors reduce metastatic burden for patients with melanomas harboring BRAF mutations; however, most eventually relapse due to acquired resistance. Here, we demonstrate that ABL1/2 kinase activities and/or expression are potentiated in cell lines and patient samples following resistance, and ABL1/2 drive BRAF and BRAF/MEK inhibitor resistance by inducing reactivation of MEK/ERK/MYC signaling. Silencing/inhibiting ABL1/2 blocks pathway reactivation, and resensitizes resistant cells to BRAF/MEK inhibitors, whereas expression of constitutively active ABL1/2 is sufficient to promote resistance. Significantly, nilotinib (2nd generation ABL1/2 inhibitor) reverses resistance, in vivo, causing prolonged regression of resistant tumors, and also, prevents BRAFi/MEKi resistance from developing in the first place. These data indicate that repurposing the FDA-approved leukemia drug, nilotinib, may be effective for prolonging survival for patients harboring BRAF-mutant melanomas.
    DOI:  https://doi.org/10.1038/s41467-020-19075-3
  5. Nat Commun. 2020 Oct 30. 11(1): 5488
    Lee KM, Guerrero-Zotano AL, Servetto A, Sudhan DR, Lin CC, Formisano L, Jansen VM, González-Ericsson P, Sanders ME, Stricker TP, Raj G, Dean KM, Fiolka R, Cantley LC, Hanker AB, Arteaga CL.
      The 17q23 amplicon is associated with poor outcome in ER+ breast cancers, but the causal genes to endocrine resistance in this amplicon are unclear. Here, we interrogate transcriptome data from primary breast tumors and find that among genes in 17q23, PRR11 is a key gene associated with a poor response to therapeutic estrogen suppression. PRR11 promotes estrogen-independent proliferation and confers endocrine resistance in ER+ breast cancers. Mechanistically, the proline-rich motif-mediated interaction of PRR11 with the p85α regulatory subunit of PI3K suppresses p85 homodimerization, thus enhancing insulin-stimulated binding of p110-p85α heterodimers to IRS1 and activation of PI3K. PRR11-amplified breast cancer cells rely on PIK3CA and are highly sensitive to PI3K inhibitors, suggesting that PRR11 amplification confers PI3K dependence. Finally, genetic and pharmacological inhibition of PI3K suppresses PRR11-mediated, estrogen-independent growth. These data suggest ER+/PRR11-amplified breast cancers as a novel subgroup of tumors that may benefit from treatment with PI3K inhibitors and antiestrogens.
    DOI:  https://doi.org/10.1038/s41467-020-19291-x
  6. Cancer Res. 2020 Oct 29. pii: canres.1601.2020. [Epub ahead of print]
    Crump LS, Wyatt G, Rutherford TR, Richer JK, Porter WW, Lyons TR.
      Approximately 70% of all breast cancers are estrogen receptor positive (ER+BC) and endocrine therapy has improved survival for patients with ER+BC. However, up to half of these tumors recur within 20 years. Recurrent ER+BCs develop resistance to endocrine therapy; thus, novel targets are needed to treat recurrent ER+BC. Here we report that semaphorin 7A (SEMA7A) confers significantly decreased patient survival rates in ER+BC. SEMA7A was hormonally regulated in ER+BC, but its expression did not uniformly decrease with anti-estrogen treatments. Additionally, overexpression of SEMA7A in ER+ cell lines drove increased in vitro growth in the presence of estrogen-deprivation, tamoxifen, and fulvestrant. In vivo, SEMA7A conferred primary tumor resistance to fulvestrant and induced lung metastases. Pro-survival signaling was identified as a therapeutic vulnerability of ER+SEMA7A+ tumors. We therefore propose that targeting this pathway with inhibitors of survival signaling such as venetoclax may prove efficacious for treating SEMA7A+ tumors.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-1601
  7. Mol Cell. 2020 Oct 21. pii: S1097-2765(20)30691-2. [Epub ahead of print]
    Li F, Kozono D, Deraska P, Branigan T, Dunn C, Zheng XF, Parmar K, Nguyen H, DeCaprio J, Shapiro GI, Chowdhury D, D'Andrea AD.
      While effective anti-cancer drugs targeting the CHK1 kinase are advancing in the clinic, drug resistance is rapidly emerging. Here, we demonstrate that CRISPR-mediated knockout of the little-known gene FAM122A/PABIR1 confers cellular resistance to CHK1 inhibitors (CHK1is) and cross-resistance to ATR inhibitors. Knockout of FAM122A results in activation of PP2A-B55α, a phosphatase that dephosphorylates the WEE1 protein and rescues WEE1 from ubiquitin-mediated degradation. The resulting increase in WEE1 protein expression reduces replication stress, activates the G2/M checkpoint, and confers cellular resistance to CHK1is. Interestingly, in tumor cells with oncogene-driven replication stress, CHK1 can directly phosphorylate FAM122A, leading to activation of the PP2A-B55α phosphatase and increased WEE1 expression. A combination of a CHK1i plus a WEE1 inhibitor can overcome CHK1i resistance of these tumor cells, thereby enhancing anti-cancer activity. The FAM122A expression level in a tumor cell can serve as a useful biomarker for predicting CHK1i sensitivity or resistance.
    Keywords:  CHK1 inhibitor; CRISPR sgRNA screening; FAM122A; Fanconi Anemia; PABIR1; PP2A; WEE1
    DOI:  https://doi.org/10.1016/j.molcel.2020.10.008
  8. Science. 2020 Oct 30. pii: eaaz0868. [Epub ahead of print]370(6516):
    Nia HT, Munn LL, Jain RK.
      The role of the physical microenvironment in tumor development, progression, metastasis, and treatment is gaining appreciation. The emerging multidisciplinary field of the physical sciences of cancer is now embraced by engineers, physicists, cell biologists, developmental biologists, tumor biologists, and oncologists attempting to understand how physical parameters and processes affect cancer progression and treatment. Discoveries in this field are starting to be translated into new therapeutic strategies for cancer. In this Review, we propose four physical traits of tumors that contribute to tumor progression and treatment resistance: (i) elevated solid stresses (compression and tension), (ii) elevated interstitial fluid pressure, (iii) altered material properties (for example, increased tissue stiffness, which historically has been used to detect cancer by palpation), and (iv) altered physical microarchitecture. After defining these physical traits, we discuss their causes, consequences, and how they complement the biological hallmarks of cancer.
    DOI:  https://doi.org/10.1126/science.aaz0868
  9. Mol Cancer Res. 2020 Oct 26. pii: molcanres.0664.2020. [Epub ahead of print]
    Terai H, Hamamoto J, Emoto K, Masuda T, Manabe T, Kuronuma S, Kobayashi K, Masuzawa K, Ikemura S, Nakayama S, Kawada I, Suzuki Y, Takeuchi O, Suzuki Y, Ohtsuki S, Yasuda H, Soejima K, Fukunaga K.
      Epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) patients respond well to treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs); however, treatment with EGFR-TKIs is not curative, owing to the presence of residual cancer cells with intrinsic or acquired resistance to this class of drugs. Additional treatment targets that may enhance the efficacy of EGFR-TKIs remain elusive. Using a CRISPR/Cas9-based screen, we identified the leucine-rich repeat scaffold protein SHOC2 as a key modulator of sensitivity to EGFR-TKI treatment. Based on in vitro assays, we demonstrated that SHOC2 expression levels strongly correlate with the sensitivity to EGFR-TKIs and that SHOC2 affects the sensitivity to EGFR-TKIs in NSCLC cells via SHOC2/MRAS/PP1c and SHOC2/SCRIB signaling. The potential SHOC2 inhibitor celastrol phenocopied SHOC2 depletion. Additionally, we confirmed that SHOC2 expression levels were important for the sensitivity to EGFR-TKIs in vivo. Furthermore, immunohistochemistry showed the accumulation of cancer cells that express high levels of SHOC2 in lung cancer tissues obtained from NSCLC patients who experienced acquired resistance to EGFR-TKIs. These data indicate that SHOC2 may be a therapeutic target for NSCLC patients or a biomarker to predict sensitivity to EGFR-TKI therapy in EGFR mutation-positive NSCLC patients. Our findings may help improve treatment strategies for NSCLC patients harboring EGFR mutations. Implications: This study showed that SHOC2 works as a modulator of sensitivity to EGFR-TKIs and the expression levels of SHOC2 can be used as a biomarker for sensitivity to EGFR-TKIs.
    DOI:  https://doi.org/10.1158/1541-7786.MCR-20-0664
  10. Cancer Res. 2020 Oct 28. pii: canres.1708.2020. [Epub ahead of print]
    Sawant Dessai A, Palestino Dominguez M, Chen UI, Hasper J, Prechtl C, Yu C, Katsuta E, Dai T, Zhu B, Jung SY, Putluri N, Takabe K, Zhang XH, O'Malley BW, Dasgupta S.
      Metabolic dysregulation is a known hallmark of cancer progression, yet the oncogenic signals that promote metabolic adaptations to drive metastatic cancer remain unclear. Here we show that transcriptional repression of mitochondrial deacetylase sirtuin 3 (SIRT3) by androgen receptor (AR) and its coregulator steroid receptor coactivator (SRC-2) enhances mitochondrial aconitase (ACO2) activity to favor aggressive prostate cancer. ACO2 promoted mitochondrial citrate synthesis to facilitate de novo lipogenesis, and genetic ablation of ACO2 reduced total lipid content and severely repressed in vivo prostate cancer progression. A single acetylation mark lysine258 on ACO2 functioned as a regulatory motif, and the acetylation-deficient Lys258Arg-mutant was enzymatically inactive and failed to rescue growth of ACO2-deficient cells. Acetylation of ACO2 was reversibly regulated by SIRT3, which was predominantly repressed in many tumors including prostate cancer. Mechanistically, SRC-2 bound AR formed a repressive complex by recruiting histone deacetylase 2 (HDAC2) to the SIRT3 promoter, and depletion of SRC-2 enhanced SIRT3 expression and simultaneously reduced acetylated-ACO2. In human prostate tumors, ACO2 activity was significantly elevated and increased expression of SRC-2 with concomitant reduction of SIRT3 was found to be a genetic hallmark enriched in prostate cancer metastatic lesions. In a mouse model of spontaneous bone metastasis, suppression of SRC-2 reactivated SIRT3 expression and was sufficient to abolish prostate cancer colonization in the bone microenvironment, implying this nuclear-mitochondrial regulatory axis is a determining factor for metastatic competence.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-1708
  11. Oncogene. 2020 Oct 29.
    Tang L, Xiong W, Zhang L, Wang D, Wang Y, Wu Y, Wei F, Mo Y, Hou X, Shi L, Xiong F, Zhang S, Gong Z, Liao Q, Xiang B, Zhang W, Zhou M, Li X, Li G, Guo C, Zeng Z.
      Circular RNAs (circRNAs) play an essential role in tumorigenesis and development. However, they have rarely been investigated in nasopharyngeal carcinoma (NPC). This study aimed to investigate the role of circRNA in the invasion and metastasis of NPC. We screened and verified the high expression of circSETD3 in NPC cell lines using RNA sequencing (RNA-Seq) and verified the results of NPC biopsy samples using real-time quantitative polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). In vivo and in vitro experiments indicated that circSETD3 could promote NPC cell invasion and migration. We compared the proteomic data of NPC cells before and after the overexpression or knockdown of circSETD3 in combination with bioinformatics prediction and experimental verification. It was found that circSETD3 competitively adsorbs to miR-615-5p and miR-1538 and negates their inhibitory effect on MAPRE1 mRNA, thereby upregulating the expression of MAPRE1. The upregulated MAPRE1 then inhibits the acetylation of α-tubulin, promotes the dynamic assembly of microtubules, and enhances the invasion and migration capabilities of NPC cells. The results of this study suggest that circSETD3 is a novel molecular marker and a potential target for NPC diagnosis and treatment.
    DOI:  https://doi.org/10.1038/s41388-020-01531-5
  12. Cancer Res. 2020 Oct 26. pii: canres.2251.2020. [Epub ahead of print]
    Sarmiento Soto M, Larkin JR, Martin C, Khrapitchev AA, Maczka M, Economopoulos V, Scott H, Escartin C, Bonvento G, Serres S, Sibson NR.
      Astrocytes are thought to play a pivotal role in coupling neural activity and cerebral blood flow. However, it has been shown that astrocytes undergo morphological changes in response to brain metastasis, switching to a reactive phenotype which has the potential to significantly compromise cerebrovascular function and contribute to the neurological sequelae associated with brain metastasis. Given that signal transducer and activator of transcription 3 (STAT3) is a key regulator of astrocyte reactivity, we aimed here to determine the impact of STAT3-mediated astrocyte reactivity on neurovascular function in brain metastasis. Rat models of brain metastasis and ciliary neurotrophic factor (CNTF) were used to induce astrocyte reactivity. Multimodal imaging, electrophysiology, and immunohistochemistry were performed to determine the relationship between reactive astrocytes and changes in the cerebrovascular response to electrical and physiological stimuli. Subsequently, the STAT3 pathway in astrocytes was inhibited with WP1066 to determine the role of STAT3-mediated astrocyte reactivity, specifically, in brain metastasis. Astrocyte reactivity associated with brain metastases impaired cerebrovascular responses to stimuli at both the cellular and functional level and disrupted astrocyte-endothelial interactions in both animal models and human brain metastasis samples. Inhibition of STAT3-mediated astrocyte reactivity in rats with brain metastases restored cerebrovascular function, as shown by in vivo imaging, and limited cerebrovascular changes associated with tumor growth. Together these findings suggest that inhibiting STAT3-mediated astrocyte reactivity may confer significant improvements in neurological outcome for patients with brain metastases and could potentially be tested in other brain tumors.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-2251
  13. Oncogene. 2020 Oct 27.
    Nimmakayala RK, Leon F, Rachagani S, Rauth S, Nallasamy P, Marimuthu S, Shailendra GK, Chhonker YS, Chugh S, Chirravuri R, Gupta R, Mallya K, Prajapati DR, Lele SM, C Caffrey T, L Grem J, Grandgenett PM, Hollingsworth MA, Murry DJ, Batra SK, Ponnusamy MP.
      Pancreatic ductal adenocarcinoma (PDAC) metastasizes to distant organs, which is the primary cause of mortality; however, specific features mediating organ-specific metastasis remain unexplored. Emerging evidence demonstrates that cancer stem cells (CSCs) and cellular metabolism play a pivotal role in metastasis. Here we investigated the role of distinct subtypes of pancreatic CSCs and their metabolomic signatures in organ-specific metastatic colonization. We found that PDAC consists of ALDH+/CD133+ and drug-resistant (MDR1+) subtypes of CSCs with specific metabolic and stemness signatures. Human PDAC tissues with gemcitabine treatment, autochthonous mouse tumors from KrasG12D; Pdx1-Cre (KC) and KrasG12D; Trp53R172H; Pdx-1 Cre (KPC) mice, and KPC- Liver/Lung metastatic cells were used to evaluate the CSC, EMT (epithelial-to-mesenchymal transition), and metabolic profiles. A strong association was observed between distinct CSC subtypes and organ-specific colonization. The liver metastasis showed drug-resistant CSC- and EMT-like phenotype with aerobic glycolysis and fatty acid β-oxidation-mediated oxidative (glyco-oxidative) metabolism. On the contrary, lung metastasis displayed ALDH+/CD133+ and MET-like phenotype with oxidative metabolism. These results were obtained by evaluating FACS-based side population (SP), autofluorescence (AF+) and Alde-red assays for CSCs, and Seahorse-based oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and fatty acid β-oxidation (FAO)-mediated OCR assays for metabolic features along with specific gene signatures. Further, we developed in vitro human liver and lung PDAC metastasis models by using a combination of liver or lung decellularized scaffolds, a co-culture, and a sphere culture methods. PDAC cells grown in the liver-mimicking model showed the enrichment of MDR1+ and CPT1A+ populations, whereas the PDAC cells grown in the lung-mimicking environment showed the enrichment of ALDH+/CD133+ populations. In addition, we observed significantly elevated expression of ALDH1 in lung metastasis and MDR1/LDH-A expression in liver metastasis compared to human primary PDAC tumors. Our studies elucidate that distinct CSCs adapt unique metabolic signatures for organotropic metastasis, which will pave the way for the development of targeted therapy for PDAC metastasis.
    DOI:  https://doi.org/10.1038/s41388-020-01518-2
  14. Proc Natl Acad Sci U S A. 2020 Oct 26. pii: 202008479. [Epub ahead of print]
    Vellky JE, McSweeney ST, Ricke EA, Ricke WA.
      Prostate cancer (CaP) driven by androgen receptor (AR) is treated with androgen deprivation; however, therapy failure results in lethal castration-resistant prostate cancer (CRPC). AR-low/negative (ARL/-) CRPC subtypes have recently been characterized and cannot be targeted by hormonal therapies, resulting in poor prognosis. RNA-binding protein (RBP)/helicase DDX3 (DEAD-box helicase 3 X-linked) is a key component of stress granules (SG) and is postulated to affect protein translation. Here, we investigated DDX3-mediated posttranscriptional regulation of AR mRNA (messenger RNA) in CRPC. Using patient samples and preclinical models, we objectively quantified DDX3 and AR expression in ARL/- CRPC. We utilized CRPC models to identify DDX3:AR mRNA complexes by RNA immunoprecipitation, assess the effects of DDX3 gain/loss-of-function on AR expression and signaling, and address clinical implications of targeting DDX3 by assessing sensitivity to AR-signaling inhibitors (ARSI) in CRPC xenografts in vivo. ARL/- CRPC expressed abundant AR mRNA despite diminished levels of AR protein. DDX3 protein was highly expressed in ARL/- CRPC, where it bound to AR mRNA. Consistent with a repressive regulatory role, DDX3 localized to cytoplasmic puncta with SG marker PABP1 in CRPC. While induction of DDX3-nucleated SGs resulted in decreased AR protein expression, inhibiting DDX3 was sufficient to restore 1) AR protein expression, 2) AR signaling, and 3) sensitivity to ARSI in vitro and in vivo. Our findings implicate the RBP protein DDX3 as a mechanism of posttranscriptional regulation for AR in CRPC. Clinically, DDX3 may be targetable for sensitizing ARL/- CRPC to AR-directed therapies.
    Keywords:  androgen independence; castration-resistant prostate cancer; double-negative prostate cancer; posttranscriptional regulation; prostate cancer
    DOI:  https://doi.org/10.1073/pnas.2008479117
  15. Cancer Discov. 2020 Oct 30.
      Expression of MDK, encoding the growth factor midkine, led to immunotherapy resistance in melanoma.
    DOI:  https://doi.org/10.1158/2159-8290.CD-RW2020-157
  16. Oncogene. 2020 Oct 30.
    Abdullah A, Akhand SS, Paez JSP, Brown W, Pan L, Libring S, Badamy M, Dykuizen E, Solorio L, Andy Tao W, Wendt MK.
      Human epidermal growth factor receptor 2 (HER2)-amplified breast cancers are treated using targeted antibodies and kinase inhibitors, but resistance to these therapies leads to systemic tumor recurrence of metastatic disease. Herein, we conducted gene expression analyses of HER2 kinase inhibitor-resistant cell lines as compared to their drug-sensitive counterparts. These data demonstrate the induction of epithelial-mesenchymal transition (EMT), which included enhanced expression of fibroblast growth factor receptor 1 (FGFR1) and axonal guidance molecules known as neuropilins (NRPs). Immunoprecipitation of FGFR1 coupled with mass spectroscopy indicated that FGFR1 forms a physical complex with NRPs, which is enhanced upon induction of EMT. Confocal imaging revealed that FGFR1 and NRP1 predominantly interact throughout the cytoplasm. Along these lines, short hairpin RNA-mediated depletion of NRP1, but not the use of NRP1-blocking antibodies, inhibited FGFR signaling and reduced tumor cell growth in vitro and in vivo. Our results further indicate that NRP1 upregulation during EMT is mediated via binding of the chromatin reader protein, bromodomain containing 4 (BRD4) in the NRP1 proximal promoter region. Pharmacological inhibition of BRD4 decreased NRP1 expression and ablated FGF-mediated tumor cell growth. Overall, our studies indicate that NRPs facilitate aberrant growth factor signaling during EMT-associated drug resistance and metastasis. Pharmacological combination of epigenetic modulators with FGFR-targeted kinase inhibitors may provide improved outcomes for breast cancer patients with drug-resistant metastatic disease.
    DOI:  https://doi.org/10.1038/s41388-020-01530-6
  17. Cancer Discov. 2020 Oct 26. pii: CD-20-0122. [Epub ahead of print]
    Gengenbacher N, Singhal M, Mogler C, Hai L, Milde L, Abdul Pari AA, Besemfelder E, Fricke C, Baumann D, Gehrs S, Utikal J, Felcht M, Hu J, Schlesner M, Offringa R, Chintharlapalli S, Augustin HG.
      Recent clinical and preclinical advances have highlighted the existence of a previously hypothesized lymphogenous route of metastasis. However, due to a lack of suitable preclinical modeling tools, its contribution to long-term disease outcome and relevance for therapy remain controversial. Here, we established a GEMM fragment-based tumor model uniquely sustaining a functional network of intratumoral lymphatics that facilitates seeding of fatal peripheral metastases. Multi-regimen survival studies and correlative patient data identified primary tumor-derived Angiopoietin-2 (Ang2) as a potent therapeutic target to restrict lymphogenous tumor cell dissemination. Mechanistically, tumor-associated lymphatic endothelial cells (EC), in contrast to blood vascular EC, were found to be critically addicted to the Angiopoietin-Tie pathway. Genetic manipulation experiments in combination with single-cell mapping revealed agonistically-acting Ang2/Tie2-signaling as key regulator of lymphatic maintenance. Correspondingly, acute pre-surgical Ang2-neutralization was sufficient to prolong survival by regressing established intratumoral lymphatics, hence identifying a novel therapeutic regimen that warrants further clinical evaluation.
    DOI:  https://doi.org/10.1158/2159-8290.CD-20-0122
  18. Mol Cancer Res. 2020 Oct 26. pii: molcanres.0480.2019. [Epub ahead of print]
    Nath A, Oak A, Chen KY, Li I, Splichal RC, Portis J, Foster S, Walton SP, Chan C.
      Elevated uptake of saturated fatty acid palmitate is associated with metastatic progression of cancer cells; however, the precise signaling mechanism behind the phenomenon is unclear. The loss of cell adhesion proteins, such as desmoplakin (DSP), is a key driving event in the transformation of cancer cells to more aggressive phenotypes. Here we investigated the mechanism by which palmitate induces the loss of DSP in liver and breast cancer cells. We propose that palmitate activates the IRE1-XBP1 branch of the endoplasmic reticulum (ER) stress pathway to upregulate the ZEB transcription factor, leading to transcriptional repression of DSP. Using liver and breast cancer cells treated with palmitate, we found loss of DSP leads to increased cell migration independent of E-cadherin. We report that the ZEB family of transcription factors function as direct transcriptional repressors of DSP. CRISPR-mediated knockdown of IRE1 confirmed that the transcription of ZEB, loss of DSP, and enhanced migration in the presence of palmitate is dependent on the IRE1-XBP1 pathway. Additionally, by analyzing the somatic expression and copy number variation profiles of over 11,000 tumor samples, we corroborate our hypothesis and establish the clinical relevance of DSP loss via ZEB in human cancers. Implications: Provides mechanistic link on palmitate-induced activation of IRE1α to cancer cell migration.
    DOI:  https://doi.org/10.1158/1541-7786.MCR-19-0480
  19. Cell. 2020 Oct 22. pii: S0092-8674(20)31305-2. [Epub ahead of print]
    Guldner IH, Wang Q, Yang L, Golomb SM, Zhao Z, Lopez JA, Brunory A, Howe EN, Zhang Y, Palakurthi B, Barron M, Gao H, Xuei X, Liu Y, Li J, Chen DZ, Landreth GE, Zhang S.
      Brain metastasis (br-met) develops in an immunologically unique br-met niche. Central nervous system-native myeloid cells (CNS-myeloids) and bone-marrow-derived myeloid cells (BMDMs) cooperatively regulate brain immunity. The phenotypic heterogeneity and specific roles of these myeloid subsets in shaping the br-met niche to regulate br-met outgrowth have not been fully revealed. Applying multimodal single-cell analyses, we elucidated a heterogeneous but spatially defined CNS-myeloid response during br-met outgrowth. We found Ccr2+ BMDMs minimally influenced br-met while CNS-myeloid promoted br-met outgrowth. Additionally, br-met-associated CNS-myeloid exhibited downregulation of Cx3cr1. Cx3cr1 knockout in CNS-myeloid increased br-met incidence, leading to an enriched interferon response signature and Cxcl10 upregulation. Significantly, neutralization of Cxcl10 reduced br-met, while rCxcl10 increased br-met and recruited VISTAHi PD-L1+ CNS-myeloid to br-met lesions. Inhibiting VISTA- and PD-L1-signaling relieved immune suppression and reduced br-met burden. Our results demonstrate that loss of Cx3cr1 in CNS-myeloid triggers a Cxcl10-mediated vicious cycle, cultivating a br-met-promoting, immune-suppressive niche.
    Keywords:  Brain metastasis; T cells; bone marrow-derived myeloid cells; brain immunity; cancer immunology; immune suppression; immune therapy; metastatic niche; microglia; tumor microenvironment
    DOI:  https://doi.org/10.1016/j.cell.2020.09.064
  20. Nat Commun. 2020 10 28. 11(1): 5436
    Kim J, Kang J, Kang YL, Woo J, Kim Y, Huh J, Park JW.
      Harmful effects of high fructose intake on health have been widely reported. Although fructose is known to promote cancer, little is known about the underlying mechanisms. Here, we found that fructose triggers breast cancer metastasis through the ketohexokinase-A signaling pathway. Molecular experiments showed that ketohexokinase-A, rather than ketohexokinase-C, is necessary and sufficient for fructose-induced cell invasion. Ketohexokinase-A-overexpressing breast cancer was found to be highly metastatic in fructose-fed mice. Mechanistically, cytoplasmic ketohexokinase-A enters into the nucleus during fructose stimulation, which is mediated by LRRC59 and KPNB1. In the nucleus, ketohexokinase-A phosphorylates YWHAH at Ser25 and the YWHAH recruits SLUG to the CDH1 promoter, which triggers cell migration. This study provides the effect of nutrition on breast cancer metastasis. High intake of fructose should be restricted in cancer patients to reduce the risk of metastasis. From a therapeutic perspective, the ketohexokinase-A signaling pathway could be a potential target to prevent cancer metastasis.
    DOI:  https://doi.org/10.1038/s41467-020-19263-1
  21. Nat Commun. 2020 10 27. 11(1): 5415
    Oba T, Long MD, Keler T, Marsh HC, Minderman H, Abrams SI, Liu S, Ito F.
      The ability of cancer cells to ensure T-cell exclusion from the tumor microenvironment is a significant mechanism of resistance to anti-PD-1/PD-L1 therapy. Evidence indicates crucial roles of Batf3-dependent conventional type-1 dendritic cells (cDC1s) for inducing antitumor T-cell immunity; however, strategies to maximize cDC1 engagement remain elusive. Here, using multiple orthotopic tumor mouse models resistant to anti-PD-L1-therapy, we are testing the hypothesis that in situ induction and activation of tumor-residing cDC1s overcomes poor T-cell infiltration. In situ immunomodulation with Flt3L, radiotherapy, and TLR3/CD40 stimulation induces an influx of stem-like Tcf1+ Slamf6+ CD8+ T cells, triggers regression not only of primary, but also untreated distant tumors, and renders tumors responsive to anti-PD-L1 therapy. Furthermore, serial in situ immunomodulation (ISIM) reshapes repertoires of intratumoral T cells, overcomes acquired resistance to anti-PD-L1 therapy, and establishes tumor-specific immunological memory. These findings provide new insights into cDC1 biology as a critical determinant to overcome mechanisms of intratumoral T-cell exclusion.
    DOI:  https://doi.org/10.1038/s41467-020-19192-z
  22. Breast Cancer Res. 2020 Oct 28. 22(1): 116
    Aqbi HF, Coleman C, Zarei M, Manjili SH, Graham L, Koblinski J, Guo C, Xie Y, Guruli G, Bear HD, Idowu MO, Habibi M, Wang XY, Manjili MH.
      BACKGROUND: Although breast cancer mortality is a result of distant recurrences associated with the establishment of tumor dormancy, current clinical practice guidelines recommend a wait and watch approach for tumor recurrences. This is because of our limited understanding of tumor dormancy and insufficient evidence in support of immunological control of tumor dormancy.METHODS: We used FVBN202 transgenic mice expressing rat neu oncogene in the mammary glands, and their parental FVB strain lacking neu expression. These models allowed the detection of tumor dormancy at distant sites using the rat neu protein as a tumor marker. We also used Ki67 for the detection of the indolent and quiescent types of tumor dormancy. Multicolor flow cytometry was used to detect dormant tumor cells and T cell subsets. Co-culture studies were performed to determine the role of T cells in preventing regrowth of dormant cells.
    RESULTS: We demonstrated that dormant tumor cells were present at the site of primary breast cancer and at distant sites in the lungs and in the liver very early in the course of early stage breast cancer when no distant metastasis was evident. Dormant tumor cells were characterized as neu expressing Ki67- and Ki67low fractions associated with the induction of local immune responses predominated by CD4+ and CD8+ T effector cell subsets. The presence of neu-autoreactive T cells from FVBN202 mice only prevented regrowth of dormant cells. On the other hand, presence of neu-alloreactive anti-tumor T cells in FVB mice prior to tumor challenge resulted in the protection of mice from the dissemination of dormant tumor cells to distant organs.
    CONCLUSION: Our results suggest that immunotherapeutic targeting of semi-allogeneic mutant neoantigens during tumor dormancy might prevent distant recurrence of the disease.
    Keywords:  Breast cancer; Cancer immunotherapy; FVBN202 transgenic mouse; T cells; Tumor dormancy
    DOI:  https://doi.org/10.1186/s13058-020-01357-9
  23. Nat Commun. 2020 Oct 30. 11(1): 5485
    Kong J, Lee H, Kim D, Han SK, Ha D, Shin K, Kim S.
      Cancer patient classification using predictive biomarkers for anti-cancer drug responses is essential for improving therapeutic outcomes. However, current machine-learning-based predictions of drug response often fail to identify robust translational biomarkers from preclinical models. Here, we present a machine-learning framework to identify robust drug biomarkers by taking advantage of network-based analyses using pharmacogenomic data derived from three-dimensional organoid culture models. The biomarkers identified by our approach accurately predict the drug responses of 114 colorectal cancer patients treated with 5-fluorouracil and 77 bladder cancer patients treated with cisplatin. We further confirm our biomarkers using external transcriptomic datasets of drug-sensitive and -resistant isogenic cancer cell lines. Finally, concordance analysis between the transcriptomic biomarkers and independent somatic mutation-based biomarkers further validate our method. This work presents a method to predict cancer patient drug responses using pharmacogenomic data derived from organoid models by combining the application of gene modules and network-based approaches.
    DOI:  https://doi.org/10.1038/s41467-020-19313-8