Decreased HCRP1 promotes breast cancer metastasis by enhancing EGFR phosphorylation.

Previous study showed that hepatocellular carcinoma related protein 1 (HCRP1) is decreased in breast cancer. HCRP1 expression is inversely related to epithelial growth factor receptor (EGFR) in breast cancer tissues, and patients with breast cancer expressing lower HCRP1 tended to suffer a shorter life expectancy. However, the detailed biological functions of HCRP1 in breast cancer as well as the interaction between HCRP1 and EGFR remain unexplored. In this study, we examined HCRP1 expression in breast cancer tissues and cell lines by western blot. Thereafter, we performed transwell migration and matrigel invasion assays after siRNA interference and lentiviral vector of HCRP1 infection. To further investigate the interaction between HCRP1 downregulation and EGFR signaling pathway, we evaluated the phosphorylation status of EGFR, Erk1/2 and Akt by western blot following HCRP1-siRNA transfection. Moreover, we investigated the in vivo functions of HCRP1 using a breast cancer xenograft model. We found that HCRP1 depletion significantly promoted breast cancer migration and invasion while HCRP1 overexpression produced an opposite effect. In addition, HCRP1 depletion decreased EGFR degradation and enhanced phosphorylation of EGFR. Interestingly, HCRP1 depletion also led to insensitivity to EGFR inhibitors treatment. The in vivo experiment confirmed the metastasis inhibition function of HCRP1. The present data indicate that HCRP1 inhibits breast cancer metastasis through downregulating EGFR phosphorylation.

ER stress elicits non-canonical CASP8 (caspase 8) activation on autophagosomal membranes to induce apoptosis.

The VPS37A gene encodes a subunit of the endosomal sorting complex required for transport (ESCRT)-I complex that is frequently lost in a wide variety of human solid cancers. We have previously demonstrated the role of VPS37A in directing the ESCRT membrane scission machinery to seal the phagophore for autophagosome completion. Here, we report that VPS37A-deficient cells exhibit an accumulation of the apoptotic initiator CASP8 (caspase 8) on the phagophore and are primed to undergo rapid apoptosis through the intracellular death-inducing signaling complex (iDISC)-mediated CASP8 activation upon exposure to endoplasmic reticulum (ER) stress. Using CRISPR-Cas9 gene editing and comparative transcriptome analysis, we identified the ATF4-mediated stress response pathway as a crucial mediator to elicit iDISC-mediated apoptosis following the inhibition of autophagosome closure. Notably, ATF4-mediated iDISC activation occurred independently of the death receptor TNFRSF10B/DR5 upregulation but required the pro-apoptotic transcriptional factor DDIT3/CHOP to enhance the mitochondrial amplification pathway for full-activation of CASP8 in VPS37A-deficient cells stimulated with ER stress inducers. Our analysis also revealed the upregulation of NFKB/NF-kB signaling as a potential mechanism responsible for restraining iDISC activation and promoting cell survival upon VPS37A depletion. These findings have important implications for the future development of new strategies to treat human cancers, especially those with VPS37A loss.Abbreviations: ATG: autophagy related; BMS: BMS-345541; CASP: caspase; CHMP: charged multivesicular body protein; DKO: double knockout; Dox: doxycycline; ER: endoplasmic reticulum; ESCRT: endosomal sorting complex required for transport; gRNA: guide RNA; GSEA: gene set enrichment analysis; GSK157: GSK2656157; iDISC: intracellular death-inducing signaling complex; IKK: inhibitor of NFKB kinase; IPA: ingenuity pathway analysis; KO: knockout; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NFKB/NF-kB: nuclear factor kappa B; OZ: 5Z-7-oxozeaenol; RNA-seq: RNA sequencing; UPR: unfolded protein response; TFT: transcription factor target; THG: thapsigargin; TUN: tunicamycin; VPS: vacuolar protein sorting.

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.