HCRP1 downregulation promotes hepatocellular carcinoma cell migration and invasion through the induction of EGFR activation and epithelial-mesenchymal transition

Unveiling the physiological impact of ESCRT-dependent autophagosome closure by targeting the VPS37A ubiquitin E2 variant-like domain

Macroautophagy (autophagy) involves the formation of phagophores that mature into autophagosomes. The impact of inhibiting autophagosome closure remains unclear. Here, we report the generation and analysis of mice with impaired autophagosome closure by targeting the ubiquitin E2 variant-like (UEVL) β strands of the endosomal sorting complex required for transport (ESCRT) I subunit VPS37A. The VPS37A UEVL mutation (Δ43-139) impairs bulk autophagic flux without disrupting ESCRT-I complex assembly and endosomal function. Homozygous mutant mice exhibit signs of autophagy impairment, including p62/SQSTM1 and ubiquitinated protein accumulation, neuronal dysfunction, growth retardation, antioxidant gene upregulation, and tissue abnormalities. However, about half of the mutant neonates survive to adulthood without severe liver injury. LC3 proximity proteomics reveals that the VPS37A UEVL mutation leads to active TANK-binding kinase 1 (TBK1) accumulation on phagophores, resulting in increased p62 phosphorylation and inclusion formation. These findings reveal a previously unappreciated role of LC3-conjugated phagophores in facilitating protein aggregation and sequestration, potentially alleviating proteotoxicity.

Systematic assessment of gene co-regulation within chromatin domains determines differentially active domains across human cancers

BACKGROUND

Spatial interactions and insulation of chromatin regions are associated with transcriptional regulation. Domains of frequent chromatin contacts are proposed as functional units, favoring and delimiting gene regulatory interactions. However, contrasting evidence supports the association between chromatin domains and transcription.

RESULT

Here, we assess gene co-regulation in chromatin domains across multiple human cancers, which exhibit great transcriptional heterogeneity. Across all datasets, gene co-regulation is observed only within a small yet significant number of chromatin domains. We design an algorithmic approach to identify differentially active domains (DADo) between two conditions and show that these provide complementary information to differentially expressed genes. Domains comprising co-regulated genes are enriched in the less active B sub-compartments and for genes with similar function. Notably, differential activation of chromatin domains is not associated with major changes of domain boundaries, but rather with changes of sub-compartments and intra-domain contacts.

CONCLUSION

Overall, gene co-regulation is observed only in a minority of chromatin domains, whose systematic identification will help unravel the relationship between chromatin structure and transcription.

Xmrks the Spot: Fish Models for Investigating Epidermal Growth Factor Receptor Signaling in Cancer Research

Studies conducted in several fish species, e.g., Xiphophorus hellerii (green swordtail) and Xiphophorus maculatus (southern platyfish) crosses, Oryzias latipes (medaka), and Danio rerio (zebrafish), have identified an oncogenic role for the receptor tyrosine kinase, Xmrk, a gene product closely related to the human epidermal growth factor receptor (EGFR), which is associated with a wide variety of pathological conditions, including cancer. Comparative analyses of Xmrk and EGFR signal transduction in melanoma have shown that both utilize STAT5 signaling to regulate apoptosis and cell proliferation, PI3K to modulate apoptosis, FAK to control migration, and the Ras/Raf/MEK/MAPK pathway to regulate cell survival, proliferation, and differentiation. Further, Xmrk and EGFR may also modulate similar chemokine, extracellular matrix, oxidative stress, and microRNA signaling pathways in melanoma. In hepatocellular carcinoma (HCC), Xmrk and EGFR signaling utilize STAT5 to regulate cell proliferation, and Xmrk may signal through PI3K and FasR to modulate apoptosis. At the same time, both activate the Ras/Raf/MEK/MAPK pathway to regulate cell proliferation and E-cadherin signaling. Xmrk models of melanoma have shown that inhibitors of PI3K and MEK have an anti-cancer effect, and in HCC, that the steroidal drug, adrenosterone, can prevent metastasis and recover E-cadherin expression, suggesting that fish Xmrk models can exploit similarities with EGFR signal transduction to identify and study new chemotherapeutic drugs.

Loss of HCRP1 leads to upregulation of PD-L1 via STAT3 activation and is of prognostic significance in EGFR-dependent cancer

Loss of hepatocellular carcinoma-related protein 1 (HCRP1) (alias VPS37A) plays a role in endocytosis of receptor tyrosine kinases as a member of the ESCRT complex and has been linked to poor patient outcome in various types of epithelial cancer. To this date, the molecular and biological mechanisms explaining how its absence would contribute to tumor progression remain unknown. Using genomic editing with CRISPR-Cas9, we generated ovarian and breast cancer cell lines with loss-of-function mutations of HCRP1. We hypothesized that pathways downstream of receptor tyrosine kinases such as epidermal growth factor receptor are affected by HCRP1 loss and looked for deregulated signaling using immunoblotting and classical cancer biology assays. In our study, we show that endogenous deletion of HCRP1 leads to elevated phosphorylation of the transcription factor Signal transducer and activator of transcription 3 (STAT3) and induces upregulation of PD-L1, an important regulator of immune checkpoint inhibition. HCRP1 loss further leads to a mesenchymal phenotype switch in cancer cells, leading to increased proliferation and migration. Concludingly, our data emphasize the role of the tumor microenvironment in tumors with low or absent HCRP1 expression and suggest HCRP1 loss as a potential marker for metastatic potential and immunogenicity of epidermal growth factor receptor-driven cancer.

Concurrent depletion of Vps37 proteins evokes ESCRT-I destabilization and profound cellular stress responses

Molecular details of how endocytosis contributes to oncogenesis remain elusive. Our in silico analysis of colorectal cancer (CRC) patients revealed stage-dependent alterations in the expression of 112 endocytosis-related genes. Among them, transcription of the endosomal sorting complex required for transport (ESCRT)-I component VPS37B was decreased in the advanced stages of CRC. Expression of other ESCRT-I core subunits remained unchanged in the investigated dataset. We analyzed an independent cohort of CRC patients, which also showed reduced VPS37A mRNA and protein abundance. Transcriptomic profiling of CRC cells revealed non-redundant functions of Vps37 proteins. Knockdown of VPS37A and VPS37B triggered p21 (CDKN1A)-mediated inhibition of cell proliferation and sterile inflammatory response driven by the nuclear factor (NF)-κB transcription factor and associated with mitogen-activated protein kinase signaling. Co-silencing of VPS37C further potentiated activation of these independently induced processes. The type and magnitude of transcriptional alterations correlated with the differential ESCRT-I stability upon individual and concurrent Vps37 depletion. Our study provides novel insights into cancer cell biology by describing cellular stress responses that are associated with ESCRT-I destabilization.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

Exosomal miRNAs: novel players in viral infection

Exosomes are secreted nanovesicles that are able to transfer their cargo (such as miRNAs) between cells. To determine to what extent exosomes and exosomal miRNAs are involved in the pathogenesis, progression and diagnosis of viral infections. The scientific literature (PubMed and Google Scholar) was searched from 1970 to 2019. The complex biogenesis of exosomes and miRNAs was reviewed. Exosomes contain both viral and host miRNAs that can be used as diagnostic biomarkers for viral diseases. Viral proteins can alter miRNAs, and conversely miRNAs can alter the host response to viral infections in a positive or negative manner. It is expected that exosomal miRNAs will be increasingly used for diagnosis, monitoring and even treatment of viral infections.

ZBTB7A promotes migration, invasion and metastasis of human breast cancer cells through NF-κB-induced epithelial-mesenchymal transition in vitro and in vivo

It has been generally confirmed that zinc finger and BTB domain containing 7A (ZBTB7A) plays an important role in the occurrence and progression of malignant tumours, but the promotion or inhibition effect is related to tumour type. The mechanism between ZBTB7A and breast cancer is not well understood, so further research is needed. In this study, we first investigated the expression of ZBTB7A in tissue samples of clinical breast cancer patients, MDA-MB-231, MCF-7 and MCF-10A cells. Second, we overexpressed the ZBTB7A in MCF-7 cells and silenced the ZBTB7A in MDA-MB-231 cells using lentivirus transfection technology, respectively, and verified the effect of ZBTB7A on migration and invasion of breast cancer cell lines through in vitro cell function experiments, such as wound-healing assay, migration and invasion assay, quantitative real time reverse transcriptase (qRT-PCR) and western blot. Then, the correlation between the above influences, epithelial-mesenchymal transition (EMT) and NF-κB was analysed. Finally, in vivo tumour transplantation model in nude mice was established to verified the effect of ZBTB7A on metastasis of breast cancer MDA-MB-231 cells. In conclusion, ZBTB7A is highly expressed in cancer tissue, breast cancer cell line MDA-MB-231 and MCF-7. Meanwhile, the high expression of ZBTB7A may promote cell migration, invasion and tumour metastasis, which may be related to EMT events by regulating NF-κB.

Inhibitory effects of genistein in combination with gefitinib on the hepatocellular carcinoma Hep3B cell line

Combination therapy is an important method for treating advanced hepatocellular carcinoma (HCC). Gefitinib is an epidermal growth factor receptor (EGFR) inhibitor, which has profound effects on HCC. The purpose of the present study was to investigate the effects of genistein in combination with gefitinib on the proliferation and apoptosis of HCC cells and the associated mechanism. Cell counting kit-8 assay was performed to calculate the IC₅₀ values and cytotoxicity, whilst flow cytometry was used to assess cell apoptosis. Protein expression was detected using western blot analysis. The IC₅₀ of genistein and gefitinib on Hep3B cells were calculated to be 128.078 and 13.657 µM, respectively. Genistein in combination with gefitinib significantly inhibited cell viability, promoted apoptosis and reduced EGFR, vascular endothelial growth factor receptor and platelet-derived growth factor receptor phosphorylation. Genistein in combination with gefitinib promoted the expression of cleaved caspase-3 and cleaved poly ADP-ribose polymerase. In addition, combined treatment of genistein and gefitinib strongly inhibited the activation of the Akt/Erk/mTOR signaling pathway. In conclusion, findings from the present study suggest that genistein in combination with gefitinib inhibit HCC cell proliferation and promote apoptosis by inhibiting the Akt/Erk/mTOR pathway.

HCRP1 inhibits cell proliferation and invasion and promotes chemosensitivity in esophageal squamous cell carcinoma

Hepatocellular carcinoma related protein 1 (HCRP1), which is essential for internalization and degradation of ubiquitinated membrane receptors, was reported to play crucial roles in cancer pathogenesis and progression. However, the functional roles of HCRP1 in esophageal squamous cell carcinoma (ESCC) remain unknown. In this study, we investigated the effects of HCRP1 on ESCC cells and the underlying mechanism. Our results demonstrated that HCRP1 was lowly expressed in ESCC tissues and cell lines. Overexpression of HCRP1 significantly suppressed ESCC cell proliferation and invasion as well as the epithelial-mesenchymal transition (EMT) process. Furthermore, HCRP1 increased the sensitivity of ESCC cells towards cisplatin/fluorouracil. Mechanistically, HCRP1 inhibited the activity of Wnt/β-catenin signaling pathway in ESCC cells. In conclusion, these findings indicated that HCRP1 suppressed ESCC cell proliferation and invasion through regulation of the Wnt/β-catenin pathway. Therefore, HCRP1 may function as a tumor suppressor in ESCC progression.

Molecular bases of the poor response of liver cancer to chemotherapy

A characteristic shared by most frequent types of primary liver cancer, i.e., hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) in adults, and in a lesser extent hepatoblastoma (HB) mainly in children, is their high refractoriness to chemotherapy. This is the result of synergic interactions among complex and diverse mechanisms of chemoresistance (MOC) in which more than 100 genes are involved. Pharmacological treatment, although it can be initially effective, frequently stimulates the expression of MOC genes, which results in the relapse of the tumor, usually with a more aggressive and less chemosensitive phenotype. Identification of the MOC genetic signature accounting for the "resistome" present at each moment of tumor life would prevent the administration of chemotherapeutic regimens without chance of success but still with noxious side effects for the patient. Moreover, a better description of cancer cells strength is required to develop novel strategies based on pharmacological, cellular or gene therapy to overcome liver cancer chemoresistance.

MicroRNA-19a acts as a prognostic marker and promotes prostate cancer progression via inhibiting VPS37A expression

Prostate cancer (PCa) is a leading cause of cancer-related deaths among males worldwide. However, the molecular mechanisms underlying the progression of PCa remain unclear. Despite several reported miRNAs in prostate cancer, these reports lacked system-level identification of differentially expressed miRNAs in large sample size. Moreover, it's still largely unknown how miRNAs result in tumorigenesis and progression of PCa. Therefore, by analyzing three public databases, we identified 16 upregulated miRNAs and 13 downregulated miRNAs, and validated miR-19a was one of the most upregulated miRNAs using qRT-PCR. The dual-luciferase reporter assays indicated VPS37A was a potential target of miR-19a. Functional assays revealed miR-19a served as an oncogene by inhibiting VPS37A. Notably, a significant inverse correlation of miR-19a and VPS37A expression was observed in PCa specimens. Moreover, miR-19a-high and VPS37A-low phenotypes were associated with poor prognosis with biochemical recurrence-free probability. In this study, we confirmed the oncogenic role of miR-19a via targeting VPS37A in PCa, identifying miR-19a and VPS37A as diagnosis and therapeutic biomarkers for PCa.

HCRP1 downregulation confers poor prognosis and induces chemoresistance through regulation of EGFR-AKT pathway in human gastric cancer

The current study aims to investigate the biological roles and clinical significance of HCRP1 in human gastric cancer. The expression pattern of HCRP1 in gastric cancer tissue and adjacent non-cancerous tissue was detected by immunohistochemistry. HCRP1 downregulation was found in 57 of 137 human gastric cancer samples and correlated with advanced TNM stage, positive nodal status, and relapse. Log-rank test showed that HCRP1 downregulation also correlated with poor overall survival and reduced relapse-free survival. In addition, we found that HCRP1 overexpression inhibited proliferation, colony formation, and invasion in HGC-27 cells. On the other hand, HCRP1 depletion by small interfering RNA promoted proliferation, colony formation, and invasion in SGC-7901 cells. We also treated gastric cancer cells with cisplatin. MTT and Annexin V/PI analysis were carried out to examine change of chemoresistance. We found that HCRP1 overexpression sensitized HGC-27 cells to cisplatin while its depletion reduced sensitivity in SGC-7901 cells. Moreover, we found that HCRP1 overexpression negatively regulated cyclin D1, MMP-2, p-EGFR, p-ERK, and p-AKT. HCRP1 depletion showed the opposite effects. In conclusion, our results suggest that HCRP1 downregulation might serve as an indicator for poor prognosis in gastric cancer patients. HCRP1 reduces drug resistance through regulation of EGFR-AKT signaling.

DAL-1 attenuates epithelial to mesenchymal transition and metastasis by suppressing HSPA5 expression in non-small cell lung cancer

Metastasis is the primary cause of death in lung cancer patients and EMT (epithelial-mesenchymal transition) promotes metastasis. Previous study revealed that DAL-1 (differentially expressed in adenocarcinoma of the lung) could attenuate EMT and metastasis in non-small cell lung cancer (NSCLC). Further study proved that HSPA5 (heat shock protein 5), which has a promoting effect on EMT, could bind to DAL-1. In this study, the mRNA and protein expression levels of target molecules were detected by RTq-PCR and western blot assays, the migration and invasion abilities were examined by Transwell migration and invasion assay, and the proliferation ability was measured by CCK-8 assay. We revealed that DAL-1 was downregulated while HSPA5 was upregulated in NSCLC and found the protein of DAL-1 and HSPA5 co-localized in the cytoplasm and nucleus. We demonstrated that DAL-1 can suppress the expression of HSPA5 on mRNA and protein levels, and decrease EMT, migration, invasion and proliferation abilities by down-regulating HSPA5. Furthermore, we discovered that DAL-1 plays a role in inhibiting PI3K/Akt/Mdm2 signaling pathway by suppressing HSPA5.

HCV-E2 inhibits hepatocellular carcinoma metastasis by stimulating mast cells to secrete exosomal shuttle microRNAs

Exosomal miRNAs are emerging as mediators of the interaction between mast cells (MCs) and tumor cells. The exosomal miRNAs can be internalized by liver cancer cells to inhibit cell metastasis. We explored the interaction between MCs and hepatocellular carcinoma (HCC) cells. We used hepatitis C virus E2 envelope glycoprotein (HCV-E2) to stimulate MCs and harvest MCs-derived exosomes to detect the miRNAs and changes of exosomal miRNAs before and after stimulation. Through miRNA microarray analysis, we identified 19 differentially expressed miRNAs in exosomes derived from MCs with or without HCV-E2 treatment. HCV-E2 not only increased the level of miRNA-490 in MCs and their secreted exosomes but also increased the levels of miRNA-490 in recipient HepG2 cells, which ultimately inhibited the ERK1/2 pathway. The transfection of antagomiR-490 significantly decreased the levels of miR-490 in MCs, MCs-derived exosomes, and recipient HepG2 cells and increased migration of HepG2, indicating that miR-490 is involved in the regulation of HepG2 cell migration. The present study suggests that MCs can inhibit HCC cell metastasis by inhibiting the ERK1/2 pathway by transferring the exosomal shuttle microRNAs into HCC cells, which provides new insights for the biological therapy of HCC induced by hepatitis C.