Molecular Cancer Research最新文献

Because of its insensitivity to existing radiotherapy, namely, chemotherapy and targeted treatments, triple-negative breast cancer (TNBC) remains a great challenge to overcome. Increasing evidence has indicated abnormal Wnt/β-catenin pathway activation in TNBC but not luminal or HER2+ breast cancer, and lncRNAs play a key role in a variety of cancers. Through lncRNA microarray profiling between activated and inactivated Wnt/β-catenin pathway of TNBC tissues, lnc-WAL (Wnt/β-catenin-associated lncRNA; WAL) was selected as the top upregulated lncRNA in Wnt/β-catenin pathway activation compared with the inactivation group. RNA immunoprecipitation sequencing was used to compare the β-catenin and IgG groups, in which lnc-WAL could interact with β-catenin. Clinically, increased lnc-WAL in TNBC tumor tissue was associated with shorter survival. lnc-WAL promoted epithelial-mesenchymal transition, the proliferation, migration, and invasion of breast cancer stem cells and TNBC cells. Mechanistically, lnc-WAL inhibited β-catenin protein degradation via AXIN-mediated phosphorylation at serine 45. Subsequently, β-catenin accumulated in the nucleus and activated the target genes. Importantly, Wnt/β-catenin pathway activation stimulated the transcription of lnc-WAL. These results pointed to a master regulatory role of lnc-WAL/AXIN/β-catenin in the malignant progression of TNBC. Our findings provide important clinical translational evidence that lnc-WAL may be a potential therapeutic target against TNBC. Implications: The positive feedback between lnc-WAL and the Wnt/β-catenin pathway promotes TNBC progression, and lnc-WAL could be a potential prognostic marker for patients with TNBC.

Heterogeneous nuclear ribonucleoprotein AB (hnRNPAB) is considered a cancer-promoting heterogeneous nuclear ribonucleoprotein in many cancers, but its function in pancreatic ductal adenocarcinoma (PDAC) is poorly understood. hnRNPAB was highly expressed in PDAC tissues compared with normal pancreatic tissues, and high expression of hnRNPAB was associated with poor overall survival and recurrence-free survival in patients with PDAC. hnRNPAB promotes migration and invasion of PDAC cells in vitro. In xenograft tumor mouse models, hnRNPAB deprivation significantly attenuated liver metastasis. hnRNPAB mRNA and protein levels are positively associated with MYC in PDAC cells. Mechanistically, hnRNPAB bound to MYC mRNA and prolonged its half-life. hnRNPAB induced PDAC cells to secrete CXCL8 via MYC, which promoted neutrophil recruitment and facilitated tumor cells entrancing into the hepatic parenchyma. These findings point to a novel regulatory mechanism via which hnRNPAB promotes PDAC metastasis. Implications: hnRNPAB participates in the posttranscriptional regulation of the oncogene MYC by binding and stabilizing MYC mRNA, thereby promoting liver metastasis in PDAC.

Ovarian cancer is one of the most common malignancies in women. Tripartite motif-containing protein 22 (TRIM22) plays an important role in the initiation and progression of malignant tumors. Similarly, the transcription factor 4 (TCF4) is an essential factor involved in the initiation and progression of many tumors. However, it is still unclear whether TRIM22 can affect TCF4 in ovarian cancer. Therefore, this study aims to investigate the mechanism related to TRIM22 and TCF4 in ovarian cancer. TRIM22 protein and mRNA levels were analyzed in samples from clinical and cell lines. The effects of TRIM22 knockdown and overexpression on cell proliferation, colony formation, migration, invasion, and related biomarkers were evaluated. In addition, the role of ubiquitination-mediated degradation of TCF4 was investigated by qRT-PCR and Western blotting. The association between TRIM22 and TCF4 was evaluated by Western blotting, coimmunoprecipitation, proliferation, colony formation, invasion, migration, and related biomarkers. The results showed that the expression of TRIM22 was minimal in ovarian cancer tissues. Furthermore, upregulation of TRIM22 significantly inhibited ovarian cancer cell proliferation, colony formation, migration, and invasion. In addition, TRIM22 was observed to regulate the degradation of TCF4 through the ubiquitination pathway. TCF4 can reverse the effects of TRIM22 on proliferation, colony formation, migration, and invasion in ovarian cancer cells. TRIM22-mediated ubiquitination of TCF4 at K48 is facilitated by the RING domain. Implications: In conclusion, ubiquitination of TCF4 protein in ovarian cancer is regulated by TRIM22, which has the potential to limit the proliferation, migration, and invasion of ovarian cancer.

The blast crisis (BC) of chronic myeloid leukemia (CML) has poor efficacy against existing treatments and extremely short survival. However, the molecular mechanism of CML-chronic phase (CP) transformation to CML-BC is not yet fully understood. Here, we show that Lin28B, an RNA-binding protein, acted as an activator enhancing the transformation to CML-BC by mediating excessive cell proliferation. The level of Lin28B expression was apparently elevated in patients with CML-BC compared with newly diagnosed patients with CML-CP. The overexpression of Lin28B promoted the proliferation of leukemia cells. Mechanistically, we identified Lin28B as a DNA-binding protein by binding to the promoter region of miR-181d and upregulating its expression, which inhibited the expression of programmed cell death 4 (PDCD4) by binding to the PDCD4 3'UTR region, thereby enhancing the proliferation of CML cells. Overall, the "Lin28B-miR-181d-PDCD4" regulatory axis promoted CML blast crisis. Implications: Our findings highlight the oncogenic role of Lin28B in CML blast crisis, acting as a DNA-binding protein that transcriptionally upregulates miR-181d expression.

Cytokinetic abscission is a crucial process that guides the separation of daughter cells at the end of each cell division. This process involves the cleavage of the intercellular bridge, which connects the newly formed daughter cells. Over the years, researchers have identified several cellular contributors and intracellular processes that influence the spatial and temporal distribution of the cytoskeleton during cytokinetic abscission. This review presents the most important scientific discoveries that allow activation of the abscission checkpoint, ensuring a smooth and successful separation of a single cell into two cells during cell division. Here, we describe different factors, such as abscission checkpoint, ICB tension, nuclear pore defects, DNA replication stress, chromosomal stability, and midbody proteins, which play a role in the regulation and correct timing of cytokinetic abscission. Furthermore, we explore the downsides associated with the dysregulation of abscission, including its negative impact on cells and the potential to induce tumor formation in humans. Finally, we propose a novel factor for improving cancer therapy and give future perspectives in this research field.

The metabolic reprogramming of aerobic glycolysis contributes to tumorigenesis. High plasma lactate is a critical regulator in the development of many human malignancies; however, the underlying molecular mechanisms of cancer progression in response to lactate (LA) remain elusive. Here, we show that the reduction of Yin-Yang 1 (YY1) expression correlated with high LA commonly occurs in various cancer cell types, including B-lymphoma and cervical cancer. Mechanistically, LA induces YY1 nuclear export and degradation via HSP70-mediated autophagy adjacent to mitochondria in a histidine (His)-rich LA-responsive (LAR) motif-dependent manner. The mutation of the LAR motif blocks LA-mediated YY1 cytoplasmic accumulation and in turn enhances cell apoptosis. Furthermore, low expression of YY1 promotes colony formation, invasion, angiogenesis, and growth of cancer cells in response to LA in vitro and in vivo using a murine xenograft model. Taken together, our findings reveal a key LAR element and may serve as therapeutic target for intervening cancer progression. Implications: We have shown that lactate can induce YY1 degradation via its His-rich LAR motif and low expression of YY1 promotes cancer cell progression in response to lactate, leading to better prediction of YY1 targeting therapy.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is caused by loss of function mutations in fumarate hydratase (FH) and results in an aggressive subtype of renal cell carcinoma with limited treatment options. Loss of FH leads to accumulation of fumarate, an oncometabolite that disrupts multiple cellular processes and drives tumor progression. High levels of fumarate inhibit alpha ketoglutarate-dependent dioxygenases, including the ten-eleven translocation (TET) enzymes, and can lead to global DNA hypermethylation. Here, we report patterns of hypermethylation in FH-mutant cell lines and tumor samples are associated with the silencing of nicotinate phosphoribosyl transferase (NAPRT), a rate-limiting enzyme in the Preiss-Handler pathway of NAD+ biosynthesis, in a subset of HLRCC cases. NAPRT is hypermethylated at a CpG island in the promoter in cell line models and patient samples, resulting in loss of NAPRT expression. We find that FH-deficient RCC models with loss of NAPRT expression, as well as other oncometabolite-producing cancer models that silence NAPRT, are extremely sensitive to nicotinamide phosphoribosyl transferase inhibitors (NAMPTi). NAPRT silencing was also associated with synergistic tumor cell killing with PARP inhibitors and NAMPTis, which was associated with effects on PAR-mediated DNA repair. Overall, our findings indicate that NAPRT silencing can be targeted in oncometabolite-producing cancers and elucidates how oncometabolite-associated hypermethylation can impact diverse cellular processes and lead to therapeutically relevant vulnerabilities in cancer cells. Implications: NAPRT is a novel biomarker for targeting NAD+ metabolism in FH-deficient HLRCCs with NAMPTis alone and targeting DNA repair processes with the combination of NAMPTis and PARP inhibitors.

Wnt (wingless-type) signaling pathway (WSP) alterations have been identified in patients with prostate cancer and are implicated in disease progression and hormonal resistance. In this study, we utilized a multi-institutional dataset to characterize molecular alterations in the canonical and noncanonical WSPs in prostate cancer. Patients with prostate cancer who underwent tissue-based genomic sequencing were investigated. Tumors with somatic activating mutations in CTNNB1 or RSPO2 or inactivating mutations in either APC or RNF43 were characterized as having aberrant canonical Wnt signaling (WSP-activated). Overall survival analyses were restricted to microsatellite-stable (MSS) tumors lacking RNF43 G659fs* mutations. We also investigated noncanonical WSP by evaluation of ROR1, ROR2, and WNT5 in WSP-activated versus WSP wild-type (WSP-WT) tumors. Of 4,138 prostate cancer samples, 3,684 were MSS. Among MSS tumors, 42.4% were from metastatic sites, of which 19.1% were WSP activated, and 57.6% were from the prostate, of which 10.1% were WSP activated. WSP-activated tumors were more prevalent in metastatic sites than in primary prostate cancer. WSP-activated prostate cancer exhibited more SPOP mutations and higher expression of canonical WSP activators than WSP-WT tumors. ROR1 gene expression was elevated in WSP-activated tumors from both primary and metastatic sites. M2 macrophages predominated the tumor microenvironment in WSP-activated tumors. There was no significant difference in overall survival between patients with WSP-activated and WSP-WT prostate cancer. WSP-activated prostate cancer demonstrated a more immunosuppressed tumor microenvironment and a pronounced upregulation of ROR1 gene expression, underscoring its potential involvement in the crosstalk between canonical and noncanonical WSPs. Implications: Our findings may provide a rationale for developing novel therapeutic strategies targeting Wnt-activated prostate cancer.

Angiosarcoma is a vascular sarcoma that is highly aggressive and metastatic. Because of its rarity, treatment options for patients are limited. Therefore, more research is needed to identify possible therapeutic vulnerabilities. We previously found that conditional deletion of Dicer1 drives angiosarcoma development in mice. Given the role of DICER1 in canonical miRNA biogenesis, this suggests that miRNA loss is important in angiosarcoma development. After testing miRNAs previously suggested to have a tumor-suppressive role in angiosarcoma, miRNA-497-5p (miR-497) suppressed cell viability most significantly. We also found that miR-497 overexpression led to significantly reduced cell migration and tumor formation. To understand the mechanism of miR-497 in tumor suppression, we identified clinically relevant target genes using a combination of RNA-sequencing data in an angiosarcoma cell line, expression data from patients with angiosarcoma, and target prediction algorithms. We validated miR-497 direct regulation of cyclin-D2, cyclin-dependent kinase 6, and vesicle amine transport protein 1 (VAT1). One of these genes, VAT1, is an understudied protein that has been suggested to promote cell migration and metastasis in other cancers. Indeed, we find that pharmacologic inhibition of VAT1 with the natural product neocarzilin A reduces angiosarcoma migration. Implications: This work supports the potent tumor-suppressive abilities of miR-497 in angiosarcoma, providing evidence for its potential as a therapeutic agent, and provides insight into the mechanisms of tumor suppression through analysis of the target gene regulatory network of miR-497.