HCRP1 regulates proliferation, invasion, and drug resistance via EGFR signaling in prostate 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.

Long non-coding RNA FAM66C is associated with clinical progression and promotes cell proliferation by inhibiting proteasome pathway in prostate cancer

Prostate cancer is the most prevalent malignancy in men, and the identification of novel oncogenes is clinically valuable for early screening, prevention and treatment. Recently, the studies have revealed that long non-coding RNAs (lncRNAs) play important roles in the development and progression of cancers including prostate cancer. The present study aims to identify a novel lncRNA that correlated with the survival time of prostate cancer patients and try to explore its biological functions in prostate cancer cells. After analysing the prostate carcinoma dataset of the Cancer Genome Atlas (TCGA), the lncRNA FAM66C was screened with its expression highly correlated with patient survival time, tumour stage and Gleason pattern. Real-time PCR showed that FAM66C highly expressed in prostate cancer cells, and knockdown FAM66C by siRNAs resulted in significant inhibition of cell growth. Furthermore, the results indicated that FAM66C promoted cell growth due to increasing cell proliferation but not decreasing cell apoptosis. In addition, FAM66C activated the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase (ERK) signalling to promote cell proliferation. The result of Western Blotting and lysosomal acidity detection showed that knockdown FAM66C increased the protein ubiquitination and the lysosomal acidity. Moreover, inhibition of proteasome pathway could increase the activation of EGFR-ERK signalling and cell proliferation. Taken together, these results suggested that lncRNA FAM66C activate EGFR-ERK signalling to promote cell proliferation by inhibiting proteasome pathway in prostate cancer. SIGNIFICANCE OF THE STUDY: We demonstrated that lncRNA FAM66C was associated with clinical progression. In addition, highly expressed lncRNA FAM66C in prostate cancer cell lines promoted cell proliferation. Moreover, lncRNA FAM66C activate the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase (ERK) signalling to promote cell proliferation by inhibiting proteasome pathway in prostate cancer. This study might provide lncRNA FAM66C as a potential therapeutic target gene of prostate cancer.

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.