bims-tucedo Biomed News
on Tumor cell dormancy
Issue of 2021‒03‒28
twenty-nine papers selected by
Isabel Puig Borreil
Vall d’Hebron Institute of Oncology

  1. Cancer Res. 2021 Mar 26. pii: canres.1713.2020. [Epub ahead of print]
      Lymph node (LN) metastasis is one of the most malignant clinical features in patients with esophageal squamous cell carcinoma (ESCC). Understanding the mechanism of LN metastasis will provide treatment strategies for ESCC patients. Long noncoding RNAs (lncRNA) play a critical role in the development and progression of human cancers. However, the role and mechanism of lncRNAs in LN metastasis remain largely unknown. Here we show that VEGF-C mRNA stability-associated long noncoding RNA (VESTAR) is involved in LN metastasis of ESCC. VESTAR was overexpressed in ESCC tissues and was predictive of poor prognosis in patients with ESCC. In ESCC, NXF1 and SRSF3 facilitated nuclear export of VESTAR to the cytoplasm, which was associated with LN metastasis. Depletion of VESTAR inhibited ESCC-associated lymphangiogenesis and lymphatic metastasis. Mechanistically, VESTAR directly bound and stabilized VEGF-C mRNA. VESTAR also interacted with HuR, a positive regulator of VEGF-C mRNA stability, and increased HuR binding to VEGF-C mRNA. Our study reveals a novel lncRNA-guided mechanism of LN metastasis in ESCC and may provide a potential target for treatment of ESCC lymphatic metastasis.
  2. Nat Commun. 2021 03 09. 12(1): 1521
      Resistance to next-generation anti-androgen enzalutamide (ENZ) constitutes a major challenge for the treatment of castration-resistant prostate cancer (CRPC). By performing genome-wide ChIP-seq profiling in ENZ-resistant CRPC cells we identify a set of androgen receptor (AR) binding sites with increased AR binding intensity (ARBS-gained). While ARBS-gained loci lack the canonical androgen response elements (ARE) and pioneer factor FOXA1 binding motifs, they are highly enriched with CpG islands and the binding sites of unmethylated CpG dinucleotide-binding protein CXXC5 and the partner TET2. RNA-seq analysis reveals that both CXXC5 and its regulated genes including ID1 are upregulated in ENZ-resistant cell lines and these results are further confirmed in patient-derived xenografts (PDXs) and patient specimens. Consistent with the finding that ARBS-gained loci are highly enriched with H3K27ac modification, ENZ-resistant PCa cells, organoids, xenografts and PDXs are hyper-sensitive to NEO2734, a dual inhibitor of BET and CBP/p300 proteins. These results not only reveal a noncanonical AR function in acquisition of ENZ resistance, but also posit a treatment strategy to target this vulnerability in ENZ-resistant CRPC.
  3. Cancer Cell Int. 2021 Mar 26. 21(1): 184
      Cancer dormancy is defined that the residual cancer cells could enter into a state of quiescence and patients remain asymptomatic for years or even decades after anti-tumor therapies. Fibroblasts, which represent a predominant cell type in tumor microenvironment, play a pivotal role in determining the ultimate fate of tumor cells. This review recapitulates the pleiotropic roles of fibroblasts which are divided into normal, senescent, cancer-associated fibroblasts (CAFs) and circulation CAFs in tumor dormancy, relapse, metastasis and resistance to therapy to help the treatment of cancer metastasis.
    Keywords:  CAF; Cancer dormancy; Cancer therapy; Fibroblast; Senescence
  4. Oncogene. 2021 Mar 25.
      Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces tumor cell-specific apoptosis, making it a prime therapeutic candidate. However, many tumor cells are either innately TRAIL-resistant, or they acquire resistance with adaptive mechanisms that remain poorly understood. In this study, we generated acquired TRAIL resistance models using multiple glioblastoma (GBM) cell lines to assess the molecular alterations in the TRAIL-resistant state. We selected TRAIL-resistant cells through chronic and long-term TRAIL exposure and noted that they showed persistent resistance both in vitro and in vivo. Among known TRAIL-sensitizers, proteosome inhibitor Bortezomib, but not HDAC inhibitor MS-275, was effective in overcoming resistance in all cell models. This was partly achieved through upregulating death receptors and pro-apoptotic proteins, and downregulating major anti-apoptotic members, Bcl-2 and Bcl-xL. We showed that CRISPR/Cas9 mediated silencing of DR5 could block Bortezomib-mediated re-sensitization, demonstrating its critical role. While overexpression of Bcl-2 or Bcl-xL was sufficient to confer resistance to TRAIL-sensitive cells, it failed to override Bortezomib-mediated re-sensitization. With RNA sequencing in multiple paired TRAIL-sensitive and TRAIL-resistant cells, we identified major alterations in inflammatory signaling, particularly in the NF-κB pathway. Inhibiting NF-κB substantially sensitized the most resistant cells to TRAIL, however, the sensitization effect was not as great as what was observed with Bortezomib. Together, our findings provide new models of acquired TRAIL resistance, which will provide essential tools to gain further insight into the heterogeneous therapy responses within GBM tumors. Additionally, these findings emphasize the critical importance of combining proteasome inhibitors and pro-apoptotic ligands to overcome acquired resistance.
  5. EMBO Mol Med. 2021 Mar 10. e13162
      Metastasis is the main cause of deaths related to solid cancers. Active transcriptional programmes are known to regulate the metastatic cascade but the molecular determinants of metastatic colonization remain elusive. Using an inducible piggyBac (PB) transposon mutagenesis screen, we have shown that overexpression of the transcription factor nuclear factor IB (NFIB) alone is sufficient to enhance primary mammary tumour growth and lung metastatic colonization. Mechanistically and functionally, NFIB directly increases expression of the oxidoreductase ERO1A, which enhances HIF1α-VEGFA-mediated angiogenesis and colonization, the last and fatal step of the metastatic cascade. NFIB is thus clinically relevant: it is preferentially expressed in the poor-prognostic group of basal-like breast cancers, and high expression of the NFIB/ERO1A/VEGFA pathway correlates with reduced breast cancer patient survival.
    Keywords:  Breast cancer; ERO1A; NFIB; VEGFA; metastasis
  6. Nat Commun. 2021 Mar 26. 12(1): 1920
      Adipogenesis associated Mth938 domain containing (AAMDC) represents an uncharacterized oncogene amplified in aggressive estrogen receptor-positive breast cancers. We uncover that AAMDC regulates the expression of several metabolic enzymes involved in the one-carbon folate and methionine cycles, and lipid metabolism. We show that AAMDC controls PI3K-AKT-mTOR signaling, regulating the translation of ATF4 and MYC and modulating the transcriptional activity of AAMDC-dependent promoters. High AAMDC expression is associated with sensitization to dactolisib and everolimus, and these PI3K-mTOR inhibitors exhibit synergistic interactions with anti-estrogens in IntClust2 models. Ectopic AAMDC expression is sufficient to activate AKT signaling, resulting in estrogen-independent tumor growth. Thus, AAMDC-overexpressing tumors may be sensitive to PI3K-mTORC1 blockers in combination with anti-estrogens. Lastly, we provide evidence that AAMDC can interact with the RabGTPase-activating protein RabGAP1L, and that AAMDC, RabGAP1L, and Rab7a colocalize in endolysosomes. The discovery of the RabGAP1L-AAMDC assembly platform provides insights for the design of selective blockers to target malignancies having the AAMDC amplification.
  7. Theranostics. 2021 ;11(9): 4298-4315
      Tumor metastasis is the leading cause of death in patients with colorectal cancer (CRC). Circular RNAs (circRNAs) have been shown to be involved in cancer progression. However, the regulatory mechanisms of circRNAs involved in CRC tumor metastasis are currently unknown. Methods: High-throughput sequencing was performed on 6 pairs of CRC and adjacent normal tissues to identify the expression profiles of mRNA and circRNA. circ1662 was assessed by RNA-ISH and IHC of a tissue chip. The function of circ1662 in CRC was evaluated by knocking down or overexpressing circ1662. MeRIP-qPCR, RIP-qPCR, and RNA pull-down were performed to determine the relationship between METTL3, circ1662, and YAP1. Results: A novel circRNA, circ1662, exhibited significantly higher expression in CRC tissues than paired normal tissues. High circ1662 expression was correlated with poor prognosis and tumor depth in patients with CRC. Functionally, circ1662 promoted CRC cell invasion and migration by controlling EMT in vitro and in vivo. Mechanistically, circ1662 directly bound to YAP1 and accelerated its nuclear accumulation to regulate the SMAD3 pathway. Additionally, circ1662 enhanced CRC invasion and migration depending on YAP1 and SMAD3. Interestingly, METTL3 induced circ1662 expression by binding its flanking sequences and installing m6A modifications. Clinically, circ1662 expression strongly correlated with METTL3 and YAP1 protein expression. Moreover, YAP1 expression was negatively correlated with SMAD3 expression. Conclusions: METTL3-induced circ1662 promoted CRC cell invasion and migration by accelerating YAP1 nuclear transport. This result implies that circ1662 is a new prognostic and therapeutic marker for CRC metastasis.
    Keywords:  METTL3; N6-methyladenosine (m6A); YAP1; circ1662; colorectal cancer
  8. Theranostics. 2021 ;11(9): 4281-4297
      Chemotherapeutic multidrug resistance (MDR) is the major hindrance for clinical therapy of colorectal cancer (CRC). Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with selective cytotoxicity might overcome MDR of CRC cells. Unfortunately, cross-resistance to TRAIL has been detected in many CRC cells, suggesting the need to combine TRAIL with sensitizers to combat refractory CRC. Our purpose is to explore the potential of combination therapy of TRAIL and tumor-cell targeted photodynamic therapy (PDT) in combating CRC with both chemotherapeutic MDR and TRAIL resistance. Methods: Tumor cell-targeted PDT was performed using a Ze-IR700 photosensitizer with high affinity for epidermal growth factor receptor (EGFR). The impact of PDT on the gene expression of CRC cells was revealed by RNA sequencing. The synergistic antitumor effect of long-acting TRAIL and PDT was evaluated in mice bearing tumor grafts of CRC cells with both chemotherapeutic MDR and TRAIL resistance. Results: Chemotherapeutic MDR and TRAIL resistance are common in CRC cells. Pretreatment of CRC cells with tumor cell-targeted PDT significantly (10-60 times) increased the sensitivity of these CRC cells to TRAIL by upregulating death receptors. Combination therapy, but not monotherapy, of long-acting TRAIL and PDT greatly induced apoptosis of CRC cells, thus efficiently eradicated large (~150 mm3) CRC tumor xenografts in mice. Conclusions: Tumor cell-targeted PDT extensively sensitizes CRC cells to TRAIL. Combination therapy of long-acting TRAIL and PDT is promising to combat CRC with both chemotherapeutic MDR and TRAIL resistance, which might be developed as a novel strategy for precision therapy of refractory CRC.
    Keywords:  Cancer targeted therapy; Colorectal cancer.; Multidrug resistance; Photodynamic therapy; Tumor necrosis factor-related apoptosis-inducing ligand
  9. Cancer Discov. 2021 Mar 23. pii: candisc.1453.2020. [Epub ahead of print]
      Clear cell renal cell carcinoma (ccRCC) is characterized by accumulation of neutral lipids and adipogenic trans-differentiation. We assessed adipokine expression in ccRCC and found that tumor tissues and patient plasma exhibit obesity-dependent elevations of the adipokine chemerin. Attenuation of chemerin by several approaches led to significant reduction in lipid deposition, and impairment of tumor cell growth in vitro and in vivo. A multi-omics approach revealed that chemerin suppresses fatty acid oxidation, preventing ferroptosis, and maintains fatty acid levels that activate HIF2a expression. The lipid CoQ and mitochondrial complex IV, whose biogenesis are lipid-dependent, were found decreased after chemerin inhibition, contributing to lipid reactive oxygen species production. Monoclonal antibody targeting chemerin led to reduced lipid storage and diminished tumor growth, demonstrating translational potential of chemerin inhibition. Collectively, the results suggest that obesity and tumor cells contribute to ccRCC through the expression of chemerin, which is indispensable in ccRCC biology.
  10. Oncogene. 2021 Mar 25.
      In solid cancers, high expression of the cellular prion protein (PrPC) is associated with stemness, invasiveness, and resistance to chemotherapy, but the role of PrPC in tumor response to radiotherapy is unknown. Here, we show that, in neuroblastoma, breast, and colorectal cancer cell lines, PrPC expression is increased after ionizing radiation (IR) and that PrPC deficiency increases radiation sensitivity and decreases radiation-induced radioresistance in tumor cells. In neuroblastoma cells, IR activates ATM that triggers TAK1-dependent phosphorylation of JNK and subsequent activation of the AP-1 transcription factor that ultimately increases PRNP promoter transcriptional activity through an AP-1 binding site in the PRNP promoter. Importantly, we show that this ATM-TAK1-PrPC pathway mediated radioresistance is activated in all tumor cell lines studied and that pharmacological inhibition of TAK1 activity recapitulates the effects of PrPC deficiency. Altogether, these results unveil how tumor cells activate PRNP to acquire resistance to radiotherapy and might have implications for therapeutic targeting of solid tumors radioresistance.
  11. Proc Natl Acad Sci U S A. 2021 Mar 30. pii: e2012748118. [Epub ahead of print]118(13):
      Cellular metabolism in cancer is significantly altered to support the uncontrolled tumor growth. How metabolic alterations contribute to hormonal therapy resistance and disease progression in prostate cancer (PCa) remains poorly understood. Here we report a glutaminase isoform switch mechanism that mediates the initial therapeutic effect but eventual failure of hormonal therapy of PCa. Androgen deprivation therapy inhibits the expression of kidney-type glutaminase (KGA), a splicing isoform of glutaminase 1 (GLS1) up-regulated by androgen receptor (AR), to achieve therapeutic effect by suppressing glutaminolysis. Eventually the tumor cells switch to the expression of glutaminase C (GAC), an androgen-independent GLS1 isoform with more potent enzymatic activity, under the androgen-deprived condition. This switch leads to increased glutamine utilization, hyperproliferation, and aggressive behavior of tumor cells. Pharmacological inhibition or RNA interference of GAC shows better treatment effect for castration-resistant PCa than for hormone-sensitive PCa in vitro and in vivo. In summary, we have identified a metabolic function of AR action in PCa and discovered that the GLS1 isoform switch is one of the key mechanisms in therapeutic resistance and disease progression.
    Keywords:  GAC; glutaminase; prostate cancer; therapeutic resistance
  12. EMBO Rep. 2021 Mar 26. e52079
      Quaking (QKI) proteins belong to the signal transduction and activation of RNA (STAR) family of RNA-binding proteins that have multiple functions in RNA biology. Here, we show that QKI-5 is dramatically decreased in metastatic lung adenocarcinoma (LUAD). QKI-5 overexpression inhibits TGF-β-induced epithelial-mesenchymal transition (EMT) and invasion, whereas QKI-5 knockdown has the opposite effect. QKI-5 overexpression and silencing suppresses and promotes TGF-β-stimulated metastasis in vivo, respectively. QKI-5 inhibits TGF-β-induced EMT and invasion in a TGFβR1-dependent manner. KLF6 knockdown increases TGFβR1 expression and promotes TGF-β-induced EMT, which is partly abrogated by QKI-5 overexpression. Mechanistically, QKI-5 directly interacts with the TGFβR1 3' UTR and causes post-transcriptional degradation of TGFβR1 mRNA, thereby inhibiting TGF-β-induced SMAD3 phosphorylation and TGF-β/SMAD signaling. QKI-5 is positively regulated by KLF6 at the transcriptional level. In LUAD tissues, KLF6 is lowly expressed and positively correlated with QKI-5 expression, while TGFβR1 expression is up-regulated and inversely correlated with QKI-5 expression. We reveal a novel mechanism by which KLF6 transcriptionally regulates QKI-5 and suggest that targeting the KLF6/QKI-5/TGFβR1 axis is a promising targeting strategy for metastatic LUAD.
    Keywords:  KLF6; QKI-5; TGF-β-induced EMT; TGFβR1; metastasis
  13. Cancer Res. 2021 Mar 24. pii: canres.3258.2020. [Epub ahead of print]
      Molecular mechanisms underlying intratumoral androgenesis and aberrant androgen receptor (AR) activation in prostate cancer (PCa) remain poorly understood. Here we demonstrate that ectopic expression of the E3 ubiquitin ligase adaptor speckle-type poxvirus and zinc finger domain protein (SPOP) stabilizes 17βHSD4. SPOP bound a functional substrate-binding consensus (SBC) motif 315RATST319 in 17βHSD4 and promoted non-degradable K27- and K29-linked poly-ubiquitination of 17βHSD4. The effect of SPOP was antagonized by serum- and glucocorticoid kinase-3 (SGK3)-mediated phosphorylation of serine 318 (S318) in the SBC and S318 phosphorylation-dependent binding of SKP2 E3 ligase and subsequent K48-linked poly-ubiquitination and proteasomal degradation of 17βHSD4. PCa-associated SPOP mutations impaired the SPOP-17βHSD4 interaction, caused 17βHSD4 protein destruction in PCa cells in culture and patient specimens, and increased testosterone production and PCa cell growth in vitro and in mouse models. Thus, we have identified SPOP and SKP2 as two essential E3 ubiquitin ligases that exert opposite effects on 17βHSD4 protein degradation and intratumoral androgenesis in PCa cells. We further demonstrate that SPOP mutations or SKP2 overexpression contribute to PCa progression by decreasing 17βHSD4 expression and increasing intratumoral androgen synthesis.
  14. Oncogene. 2021 Mar 09.
      Castration-resistant prostate cancer (CRPC) almost invariably occurs after androgen-deprivation therapy (ADT) for the advanced metastatic disease. It is generally believed that among multiple mechanisms and signaling pathways, CRPC is significantly driven by the reactivation of androgen receptor (AR) signaling in ADT-treated patients with castrate levels of androgen, partially at least mediated by the androgen biosynthesis within the tumor, also known as intratumoral or intraprostatic androgen biosynthesis. Steroidogenic enzymes, such as CYP11A1, CYP17A1, HSD3B1, AKR1C3 and SRD5A, are essential to catalyze the conversion of the initial substrate cholesterol into potent androgens that confers the CRPC progression. Accumulating evidences indicate that many steroidogenic enzymes are upregulated in the progression setting; however, little is known about the dysregulation of these enzymes in CRPC. Orphan nuclear receptors (ONRs) are members of the nuclear receptor superfamily, of which endogenous physiological ligands are unknown and which are constitutively active independent of any physiological ligands. Studies have validated that besides AR, ONRs could be the potential therapeutic targets for prostate cancer, particularly the lethal CRPC progression. Early studies reveal that ONRs play crucial roles in the transcriptional regulation of steroidogenic enzyme genes. Notably, we and others show that three distinct ONRs, including liver receptor homolog-1 (LRH-1, NR5A2), steroidogenic factor 1 (SF-1, AD4BP, NR5A1) and estrogen-related receptor α (ERRα, NR3B1), can contribute to the CRPC progression by promotion of the intratumoral androgen synthesis via their direct transcriptional regulation on multiple steroidogenic enzymes. This review presents an overview of the current understanding on the intratumoral androgen biosynthesis in CRPC, with a special focus on the emerging roles of ONRs in this process.
  15. Nature. 2021 Mar 24.
      Our knowledge of copy number evolution during the expansion of primary breast tumours is limited1,2. Here, to investigate this process, we developed a single-cell, single-molecule DNA-sequencing method and performed copy number analysis of 16,178 single cells from 8 human triple-negative breast cancers and 4 cell lines. The results show that breast tumours and cell lines comprise a large milieu of subclones (7-22) that are organized into a few (3-5) major superclones. Evolutionary analysis suggests that after clonal TP53 mutations, multiple loss-of-heterozygosity events and genome doubling, there was a period of transient genomic instability followed by ongoing copy number evolution during the primary tumour expansion. By subcloning single daughter cells in culture, we show that tumour cells rediversify their genomes and do not retain isogenic properties. These data show that triple-negative breast cancers continue to evolve chromosome aberrations and maintain a reservoir of subclonal diversity during primary tumour growth.
  16. Cell. 2021 Mar 19. pii: S0092-8674(21)00237-3. [Epub ahead of print]
      Metastasis is the leading cause of cancer-related deaths, and greater knowledge of the metastatic microenvironment is necessary to effectively target this process. Microenvironmental changes occur at distant sites prior to clinically detectable metastatic disease; however, the key niche regulatory signals during metastatic progression remain poorly characterized. Here, we identify a core immune suppression gene signature in pre-metastatic niche formation that is expressed predominantly by myeloid cells. We target this immune suppression program by utilizing genetically engineered myeloid cells (GEMys) to deliver IL-12 to modulate the metastatic microenvironment. Our data demonstrate that IL12-GEMy treatment reverses immune suppression in the pre-metastatic niche by activating antigen presentation and T cell activation, resulting in reduced metastatic and primary tumor burden and improved survival of tumor-bearing mice. We demonstrate that IL12-GEMys can functionally modulate the core program of immune suppression in the pre-metastatic niche to successfully rebalance the dysregulated metastatic microenvironment in cancer.
    Keywords:  T cells; cancer immunology; genetically engineered myeloid cells; immune suppression; immunotherapy; interleukin 12; metastasis tumor microenvironment; pre-metastatic niche; stem cell niche
  17. Gastroenterology. 2021 Mar 19. pii: S0016-5085(21)00536-9. [Epub ahead of print]
      BACKGROUND & AIMS: Tumor-infiltrating neutrophils (PMNs) are a prominent feature of colorectal cancer (CRC), where they can promote cytotoxicity or exacerbate disease outcomes. We recently showed that in acute colon injury, PMNs can increase DNA double-strand breaks (DSB) burden and promote genomic instability via microRNA-dependent inhibition of homologous recombination (HR) repair. In this study, we aimed to establish whether in inflamed colon, neutrophils shape the DSB-repair responses to impact CRC progression and sensitivity/resistance to DNA-repair targeted therapy.METHODS: Human sporadic CRC biopsies, TCGA gene expression analyses, tumor xenografts and murine CRC models, as well as small-molecule inhibition of key DSB-repair factors were leveraged to investigate changes in the DSB-repair landscape and identify unique CRC responses with/without tumor-infiltration by PMNs.
    RESULTS: We reveal that neutrophils exert a functional dualism in cancer cells, driving temporal modulation of the DNA damage landscape and resolution of DSBs. PMNs were found to promote HR-deficiency in low-grade CRC by miR-155-dependent downregulation of RAD51, thus attenuating tumor growth. However, neutrophil-mediated genotoxicity due to accumulation of DSBs led to the induction of non-homologous end-joining (NHEJ), allowing for survival and growth of advanced CRC. Our findings identified a PMN-induced HR-deficient CRC phenotype, featuring low RAD51 and low Ku70 levels, rendering it susceptible to synthetic lethality induced by clinically approved PARP1 inhibitor Olaparib. We further identified a distinct PMN-induced HR-deficient CRC phenotype, featuring high Ku70 and heightened NHEJ, which can be therapeutically targeted by specific inhibition of NHEJ.
    CONCLUSIONS: Our work delineates two mechanism-based translatable therapeutic interventions in sporadic CRC.
    Keywords:  DSB; Ku70; Rad51; colon cancer; microRNA
  18. EMBO Mol Med. 2021 Mar 23. e13412
      The tumor microenvironment in brain metastases is characterized by high myeloid cell content associated with immune suppressive and cancer-permissive functions. Moreover, brain metastases induce the recruitment of lymphocytes. Despite their presence, T-cell-directed therapies fail to elicit effective anti-tumor immune responses. Here, we seek to evaluate the applicability of radio-immunotherapy to modulate tumor immunity and overcome inhibitory effects that diminish anti-cancer activity. Radiotherapy-induced immune modulation resulted in an increase in cytotoxic T-cell numbers and prevented the induction of lymphocyte-mediated immune suppression. Radio-immunotherapy led to significantly improved tumor control with prolonged median survival in experimental breast-to-brain metastasis. However, long-term efficacy was not observed. Recurrent brain metastases showed accumulation of blood-borne PD-L1+ myeloid cells after radio-immunotherapy indicating the establishment of an immune suppressive environment to counteract re-activated T-cell responses. This finding was further supported by transcriptional analyses indicating a crucial role for monocyte-derived macrophages in mediating immune suppression and regulating T-cell function. Therefore, selective targeting of immune suppressive functions of myeloid cells is expected to be critical for improved therapeutic efficacy of radio-immunotherapy in brain metastases.
    Keywords:  brain cancer; checkpoint inhibitors; microglia; tumor microenvironment; tumor-associated macrophages
  19. Cancer Res. 2021 Mar 22. pii: canres.2870.2020. [Epub ahead of print]
      Neutrophils are the most abundant circulating leucocytes and are essential for innate immunity. In cancer, pro- or anti-tumor properties have been attributed to tumor-associated neutrophils (TAN). Here, focusing on TAN accumulation within lung tumors, we identify Glut1 as an essential glucose transporter for their tumor supportive behavior. Compared to normal neutrophils, Glut1 and glucose metabolism increased in TANs from a mouse model of lung adenocarcinoma. To elucidate the impact of glucose uptake on TANs, we used a strategy with two recombinases, dissociating tumor initiation from neutrophil-specific Glut1 deletion. Loss of Glut1 accelerated neutrophil turnover in tumors and reduced a subset of TANs expressing SiglecF. In the absence of Glut1 expression by TANs, tumor growth was diminished and the efficacy of radiotherapy was augmented. Our results demonstrate the importance of Glut1 in TANs, which may affect their pro- versus anti-tumor behavior. These results also suggest targeting metabolic vulnerabilities to favor anti-tumor neutrophils.
  20. Cancer Discov. 2021 Mar 26.
      Blocking autophagy in cancer cells triggered transcription factor NRF2 to induce macropinocytosis.
  21. Sci Adv. 2021 Mar;pii: eabc5267. [Epub ahead of print]7(13):
      Various cancers treated with cisplatin almost invariably develop drug resistance that is frequently caused by substantial DNA repair. We searched for acquired vulnerabilities of cisplatin-resistant cancers to identify undiscovered therapy. We herein found that cisplatin resistance of cancer cells comes at a fitness cost of increased intracellular hypoxia. Then, we conceived an inspired strategy to combat the tumor drug resistance by exploiting the increased intracellular hypoxia that occurs as the cells develop drug resistance. Here, we constructed a hypoxia-amplifying DNA repair-inhibiting liposomal nanomedicine (denoted as HYDRI NM), which is formulated from a platinum(IV) prodrug as a building block and payloads of glucose oxidase (GOx) and hypoxia-activatable tirapazamine (TPZ). In studies on clinically relevant models, including patient-derived organoids and patient-derived xenograft tumors, the HYDRI NM is able to effectively suppress the growth of cisplatin-resistant tumors. Thus, this study provides clinical proof of concept for the therapy identified here.
  22. Mol Metab. 2021 Mar 22. pii: S2212-8778(21)00061-2. [Epub ahead of print] 101217
      OBJECTIVE: Metabolic deregulation is a key hallmark of cancer cells and has been shown to drive cancer growth and metastasis. However, not all metabolic drivers of melanoma are known. Based on our finding that N-acylsphingosine amidohydrolase 1 (ASAH1) is overexpressed in melanoma, the objective of these studies was to establish its role in melanoma tumor growth and metastasis, understand its mechanism of action, and evaluate ASAH1 targeting for melanoma therapy.METHODS: We used publicly available melanoma datasets and patient-derived samples of melanoma and normal skin tissue and analyzed them for ASAH1 mRNA expression and ASAH1 protein expression using immunohistochemistry. ASAH1 was knocked down using short-hairpin RNAs in multiple melanoma cell lines that were tested in a series of cell culture-based assays and mouse-based melanoma xenograft assays to monitor the effect of ASAH1 knockdown on melanoma tumor growth and metastasis. Unbiased metabolomics analysis was performed to identify the mechanism of ASAH1 action. Based on the findings of the metabolomics, the role of peroxisome-mediated reactive oxygen species (ROS) production was explored in regard to mediating the effect of ASAH1. Finally, the ASAH1 inhibitor was used alone or in combination with a BRAFV600E inhibitor to evaluate the therapeutic value of ASAH1 targeting for melanoma therapy.
    RESULTS: We determined that ASAH1 was overexpressed in a large percentage of melanoma cells and regulated by transcription factor E2F1 in a mitogen-activated protein (MAP) kinase pathway-dependent manner. ASAH1 expression was necessary to maintain melanoma tumor growth and metastatic attributes both in cell culture and in mouse models of melanoma tumor growth and metastasis. To identify the mechanism by which ASAH1 facilitates melanoma tumor growth and metastasis, we performed a large-scale and unbiased metabolomics analysis of melanoma cells expressing ASAH1 short-hairpin RNAs (shRNAs). We found that ASAH1 inhibition increased peroxisome biogenesis through ceramide-mediated PPARγ activation. ASAH1 loss increased ceramide and peroxisome-derived ROS, which in turn inhibited melanoma growth. Pharmacological inhibition of ASAH1 also attenuated melanoma growth and enhanced the effectiveness of BRAF kinase inhibitor in cell culture and in mice.
    CONCLUSIONS: Collectively, these results demonstrate that ASAH1 is a druggable driver of melanoma tumor growth and metastasis that functions by suppressing peroxisome biogenesis and thereby inhibiting peroxisome-derived ROS production. These studies also highlight the therapeutic utility of ASAH1 inhibitors for melanoma therapy.
    Keywords:  ASAH1; Cancer therapeutics; Ceramide; Melanoma; Peroxisome; ROS
  23. Theranostics. 2021 ;11(9): 4403-4420
      Rationale: In breast cancer, high intratumor DNA methylation heterogeneity can lead to drug-resistant, metastasis and poor prognosis of tumors, which increases the complexity of cancer diagnosis and treatment. However, most studies are limited to average DNA methylation level of individual CpGs and ignore heterogeneous DNA methylation patterns of cell subpopulations within the tumor. Thus, quantifying the variability in DNA methylation pattern in sequencing reads is valuable for understanding intratumor heterogeneity. Methods: We performed Reduced Representation Bisulfite Sequencing and RNA sequencing for tumor core and tumor periphery regions within one breast tumor. By developing a method named "epialleJS" based on Jensen-Shannon divergence, we detected the differential epialleles between tumor core and tumor periphery (CPDEs). We then explored the correlation between intratumor methylation heterogeneity and hypoxic microenvironment in TCGA breast cancer cohort. Results: More than 70% of CPDEs had higher epipolymorphism in tumor core than tumor periphery, and these CPDEs had lower methylation in tumor core. The CPDEs with lower methylation in tumor core may associate with hypoxic tumor microenvironment. Moreover, we identified a signature of five hypoxia-related DNA methylation markers which can predict the prognosis of breast cancer patients, including a CpG site cg15190451 in gene SLC16A5. Furthermore, immunohistochemical analysis confirmed that the expression of SLC16A5 was associated with clinicopathological characteristics and survival of breast cancer patients. Conclusions: The analysis of intratumor DNA methylation heterogeneity based on epialleles reveals that disordered methylation patterns in tumor core are associated with hypoxic microenvironment, which provides a framework for understanding biological heterogeneous behavior and guidance for developing effective treatment schemes for breast cancer patients.
    Keywords:  breast cancer; epiallele; hypoxic microenvironment.; intratumor DNA methylation heterogeneity; methylation patterns
  24. N Engl J Med. 2021 03 25. pii: 10.1056/NEJMc2100225#sa3. [Epub ahead of print]384(12): 1175
  25. Theranostics. 2021 ;11(9): 4421-4435
      Background: Amino-terminal enhancer of split (AES) has been identified as a tumor and metastasis suppressor in some cancers including colorectal cancer (CRC), but very little is known about the regulation of AES expression. Methods: Bioinformatics analysis was used to investigate the expression patterns of AES, CK1δ and CK1ε. The co-immunoprecipitation, GST pull-down, Western Blot, real-time PCR and immunohistochemistry were performed to study the mechanism underlying the regulation of AES expression by CK1δ/ε. The biological function was assessed by in vitro colony formation, transwell, sphere formation, tumor organoids, in vivo tumor metastasis model and patient-derived colorectal tumor xenografts (PDTX) model. Results: A strong inverse relationship was observed between the expression of AES and the expression of CK1δ/ε. Mechanically, AES could interact with CK1δ/ε and SKP2 using its Q domain. SKP2 mediated the ubiquitination and degradation of AES in a CK1δ/ε-dependent manner. CK1δ/ε phosphorylated AES at Ser121 and accelerated the SKP2-mediated ubiquitination and degradation of AES. In colon cancer cells, CK1δ/ε antagonized the effect of wild-type AES but not that of its mutant (S121A) on Wnt and Notch signaling, leading to an increase in the expression of Wnt target genes and Notch target genes. By downregulating the expression of AES, CK1δ/ε enhanced anchorage-independent growth, migration, invasion and sphere formation in colon cancer cells. CK1δ/ε also promoted the growth of APCmin/+ colorectal tumor organoids and liver metastasis in colon cancer mouse models through the regulation of AES degradation. Furthermore, CK1 inhibitor SR3029 treatment suppressed tumor growth via stabilizing AES in APCmin/+ colorectal tumor organoids and patient-derived colorectal tumor xenografts (PDTX). Conclusions: Our results revealed that the CK1δ/ε-AES axis is important for CRC tumorigenesis and metastasis, and targeted inhibition of this axis may be a potential therapeutic strategy for CRC.
    Keywords:  AES; CK1δ/ε; SKP2; Wnt/β-catenin signaling; colorectal cancer
  26. Theranostics. 2021 ;11(10): 4839-4857
      Reactive oxygen species (ROS) serve as cell signaling molecules generated in oxidative metabolism and are associated with a number of human diseases. The reprogramming of redox metabolism induces abnormal accumulation of ROS in cancer cells. It has been widely accepted that ROS play opposite roles in tumor growth, metastasis and apoptosis according to their different distributions, concentrations and durations in specific subcellular structures. These double-edged roles in cancer progression include the ROS-dependent malignant transformation and the oxidative stress-induced cell death. In this review, we summarize the notable literatures on ROS generation and scavenging, and discuss the related signal transduction networks and corresponding anticancer therapies. There is no doubt that an improved understanding of the sophisticated mechanism of redox biology is imperative to conquer cancer.
  27. Proc Natl Acad Sci U S A. 2021 Mar 30. pii: e2008772118. [Epub ahead of print]118(13):
      Most glioblastomas (GBMs) achieve cellular immortality by acquiring a mutation in the telomerase reverse transcriptase (TERT) promoter. TERT promoter mutations create a binding site for a GA binding protein (GABP) transcription factor complex, whose assembly at the promoter is associated with TERT reactivation and telomere maintenance. Here, we demonstrate increased binding of a specific GABPB1L-isoform-containing complex to the mutant TERT promoter. Furthermore, we find that TERT promoter mutant GBM cells, unlike wild-type cells, exhibit a critical near-term dependence on GABPB1L for proliferation, notably also posttumor establishment in vivo. Up-regulation of the protein paralogue GABPB2, which is normally expressed at very low levels, can rescue this dependence. More importantly, when combined with frontline temozolomide (TMZ) chemotherapy, inducible GABPB1L knockdown and the associated TERT reduction led to an impaired DNA damage response that resulted in profoundly reduced growth of intracranial GBM tumors. Together, these findings provide insights into the mechanism of cancer-specific TERT regulation, uncover rapid effects of GABPB1L-mediated TERT suppression in GBM maintenance, and establish GABPB1L inhibition in combination with chemotherapy as a therapeutic strategy for TERT promoter mutant GBM.
    Keywords:  CRISPR; TERT; cancer; glioblastoma; temozolomide
  28. Theranostics. 2021 ;11(10): 4809-4824
      Purpose: Advanced prostate cancer (PCa) has limited treatment regimens and shows low response to chemotherapy and immunotherapy, leading to poor prognosis. Histone modification is a vital mechanism of gene expression and a promising therapy target. In this study, we characterized WD repeat domain 5 (WDR5), a regulator of histone modification, and explored its potential therapeutic value in PCa. Experimental Design: We characterized specific regulators of histone modification, based on TCGA data. The expression and clinical features of WDR5 were analyzed in two dependent cohorts. The functional role of WDR5 was further investigated with siRNA and OICR-9429, a small molecular antagonist of WDR5, in vitro and in vivo. The mechanism of WDR5 was explored by RNA-sequencing and chromatin immunoprecipitation (ChIP). Results: WDR5 was overexpressed in PCa and associated with advanced clinicopathological features, and predicted poor prognosis. Both inhibition of WDR5 by siRNA and OICR-9429 could reduce proliferation, and increase apoptosis and chemosensitivity to cisplatin in vitro and in vivo. Interestingly, targeting WDR5 by siRNA and OICR-9429 could block IFN-γ-induced PD-L1 expression in PCa cells. Mechanistically, we clarified that some cell cycle, anti-apoptosis, DNA repair and immune related genes, including AURKA, CCNB1, E2F1, PLK1, BIRC5, XRCC2 and PD-L1, were directly regulated by WDR5 and OICR-9429 in H3K4me3 and c-Myc dependent manner. Conclusions: These data revealed that targeting WDR5 suppressed proliferation, enhanced apoptosis, chemosensitivity to cisplatin and immunotherapy in PCa. Therefore, our findings provide insight into OICR-9429 is a multi-potency and promising therapy drug, which improves the antitumor effect of cisplatin or immunotherapy in PCa.
    Keywords:  OICR-9429; PD-L1; Prostate cancer; WDR5; chemoresistance