Overexpression of OLC1 promotes tumorigenesis of human esophageal squamous cell carcinoma

Accessory ESCRT-III proteins are conserved and selective regulators of Rab11a-exosome formation

Exosomes are secreted nanovesicles with potent signalling activity that are initially formed as intraluminal vesicles (ILVs) in late Rab7-positive multivesicular endosomes, and also in recycling Rab11a-positive endosomes, particularly under some forms of nutrient stress. The core proteins of the Endosomal Sorting Complex Required for Transport (ESCRT) participate in exosome biogenesis and ILV-mediated destruction of ubiquitinylated cargos. Accessory ESCRT-III components have reported roles in ESCRT-III-mediated vesicle scission, but their precise functions are poorly defined. They frequently only appear essential under stress. Comparative proteomics analysis of human small extracellular vesicles revealed that accessory ESCRT-III proteins, CHMP1A, CHMP1B, CHMP5 and IST1, are increased in Rab11a-enriched exosome preparations. We show that these proteins are required to form ILVs in Drosophila secondary cell recycling endosomes, but unlike core ESCRTs, they are not involved in degradation of ubiquitinylated proteins in late endosomes. Furthermore, CHMP5 knockdown in human HCT116 colorectal cancer cells selectively inhibits Rab11a-exosome production. Accessory ESCRT-III knockdown suppresses seminal fluid-mediated reproductive signalling by secondary cells and the growth-promoting activity of Rab11a-exosome-containing EVs from HCT116 cells. We conclude that accessory ESCRT-III components have a specific, ubiquitin-independent role in Rab11a-exosome generation, a mechanism that might be targeted to selectively block pro-tumorigenic activities of these vesicles in cancer.

Bioinformatics Characterization of Candidate Genes Associated with Gene Network and miRNA Regulation in Esophageal Squamous Cell Carcinoma Patients

The present study aimed to identify potential therapeutic targets for esophageal squamous cell carcinoma (ESCC). The gene expression profile GSE161533 contained 84 samples, in that 28 tumor tissues and 28 normal tissues encoded as ESCC patients were retrieved from the Gene Expression Omnibus database. The obtained data were validated and screened for differentially expressed genes (DEGs) between normal and tumor tissues with the GEO2R tool. Next, the protein–protein network (PPI) was constructed using the (STRING 2.0) and reconstructed with Cytoscape 3.8.2, and the top ten hub genes (HGsT10) were predicted using the Maximal Clique Centrality (MCC) algorithm of the CytoHubba plugin. The identified hub genes were mapped in GSE161533, and their expression was determined and compared with The Cancer Genome Atlas (TCGA.) ESCC patient’s samples. The overall survival rate for HGsT10 wild and mutated types was analyzed with the Gene Expression Profiling Interactive Analysis2 (GEPIA2) server and UCSC Xena database. The functional and pathway enrichment analysis was performed using the WebGestalt database with the reference gene from lumina human ref 8.v3.0 version. The promoter methylation for the HGsT10 was identified using the UALCAN server. Additionally, the miRNA-HGsT10 regulatory network was constructed to identify the top ten hub miRNAs (miRT10). Finally, we identified the top ten novel driving genes from the DEGs of GSE161533 ESCC patient’s sample using a multi-omics approach. It may provide new insights into the diagnosis and treatment for the ESCC affected patients early in the future.

Regulation of OLC1 protein expression by the anaphase-promoting complex

Overexpressed in lung cancer 1 (OLC1) is a potential oncogene overexpressed in human lung cancer and in other types of malignant tumor. The elevated expression of OLC1 contributes to tumor genesis and progression. However, the mechanisms regulating the expression of OLC1 remain unclear. In the present study, using lung and esophageal cancer cell lines, it was demonstrated that OLC1 was a short-lived, cell cycle-dependent protein regulated through the anaphase-promoting complex/cyclosome (APC/c)-ubiquitin pathway by directly interacting with the APC2 subunit. Through the action of two co activator proteins, cadherin 1 (Cdh1) and cell-division cycle protein 20 (Cdc20), the OLC1 protein was ubiquitinated and degraded. Following treatment with a proteasome inhibitor, OLC1 protein levels were elevated. Inversely, the upregulation of Cdh1 and Cdc20 facilitated OLC1 degradation. By inducing point mutations of the assumed degradation motif of OLC1, it was revealed that an intact destruction (D)-box was necessary. As expected, the D-box-mutated OLC1 exhibited a higher capacity for promoting cell growth and clone formation. Collectively, these findings indicate that the expression of the candidate oncogene OLC1 is cell cycle-dependent and is regulated by an APC/c mediated ubiquitin-proteasome pathway.

Nuclear overexpression of the overexpressed in lung cancer 1 predicts worse prognosis in gastric adenocarcinoma

We have performed this retrospective study to elucidate whether elevated expression of the overexpressed in lung cancer 1 (OLC1) was related to the clinicopathological parameters and prognosis of patients with gastric adenocarcinoma. Additionally, different effects of various subcellular OLC1 expression on gastric adeno-carcinogenesis were focused on in our study. Both overall and subcellular expression of OLC1 was evaluated by immunohistochemistry(IHC) via tissue microarrays from total 393 samples. The Kaplan-Meier method and Cox's proportional hazard model were exerted to further explore the correlation between OLC1 and prognosis. Total overexpression of OLC1 was significantly associated with stage (P = 0.004) and differentiation (P = 0.009), and only the strong total expression could predict a poor prognosis (HR = 1.31, P = 0.04). There were significant associations found between nuclear overexpression and tumor invasion depth(P = 0.002), lymph node (P < 0.001), stage (P = 0.004), differentiation (P < 0.001) and smoking history (P = 0.045). Furthermore, over-expressed nuclear OLC1 protein could be an independent risk factor for gastric adenocarcinoma (univariate: HR = 1.43, P = 0.003; multivariate: HR = 1.39, P = 0.011). In general, both total and nuclear overexpression of OLC1 could be the signs of gastric adeno-carcinogenesis, which might be served as the biomarkers for diagnosis at an early stage, even at the onset of tumorigenesis. Rather than the total expression, nuclear overexpression of OLC1 was correlated with most clinicopathological parameters and could predict a poor overall survival as an independent factor for prognosis, which made it a more effective and sensitive biomarker for gastric adenocarcinoma.

[Overexpression of OLC1 in Lung Squamous Cell Carcinoma Tissues is Associated with Poor Prognosis of Patients]

BACKGROUND

OLC1 (overexpressed in lung cancer 1), screened out and cloned in our previous research, is a new gene associated with lung cancer. It is highly expressed in lung cancer and many other malignant tumors, and is associated with poor prognosis of esophageal squamous cell carcinoma, ovarian cancer, breast cancer and colorectal cancer. The aim of this research was to detect the expression level of OLC1 in the tumor tissues of lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) and explore its relationship with the prognosis of lung cancer patients.

METHODS

Lung cancer tissues of 108 SCC and 90 ADC was dealed with immunohistochemical staining to detect the expression level of OLC1. The relationship between the expression level of OLC1 and clinical parameters and prognosis was analyzed.

RESULTS

The rate of high expression of OLC1 staining in ADC was significantly higher than that in SCC (87.5% vs 55.3%, P<0.001). The overexpression of OLC1 in tumor tissues did not have a significant relationship with the prognosis of patients with ADC, but it was related with a poor prognosis of SCC patients as the univariate analysis showed. However the multivariate regression analysis showed that correlation between the overexpression of OLC1 and poor prognosis of SCC patients did not have a statistical significance (P=0.05).

CONCLUSIONS

The expression of OLC1 in ADC might be higher than that in SCC. A higher score of OLC1 staining in tumor tissue was associated with a poorer prognosis of patients with SCC, but could not be an independent predictor for a shorter overall survival in patients with SCC.

[Overexpression of OLC1 in Lung Squamous Cell Carcinoma Tissues is Associated with Poor Prognosis of Patients]

BACKGROUND

OLC1 (overexpressed in lung cancer 1), screened out and cloned in our previous research, is a new gene associated with lung cancer. It is highly expressed in lung cancer and many other malignant tumors, and is associated with poor prognosis of esophageal squamous cell carcinoma, ovarian cancer, breast cancer and colorectal cancer. The aim of this research was to detect the expression level of OLC1 in the tumor tissues of lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) and explore its relationship with the prognosis of lung cancer patients.

METHODS

Lung cancer tissues of 108 SCC and 90 ADC was dealed with immunohistochemical staining to detect the expression level of OLC1. The relationship between the expression level of OLC1 and clinical parameters and prognosis was analyzed.

RESULTS

The rate of high expression of OLC1 staining in ADC was significantly higher than that in SCC (87.5% vs 55.3%, P<0.001). The overexpression of OLC1 in tumor tissues did not have a significant relationship with the prognosis of patients with ADC, but it was related with a poor prognosis of SCC patients as the univariate analysis showed. However the multivariate regression analysis showed that correlation between the overexpression of OLC1 and poor prognosis of SCC patients did not have a statistical significance (P=0.05).

CONCLUSIONS

The expression of OLC1 in ADC might be higher than that in SCC. A higher score of OLC1 staining in tumor tissue was associated with a poorer prognosis of patients with SCC, but could not be an independent predictor for a shorter overall survival in patients with SCC.

Upregulated KLK10 inhibits esophageal cancer proliferation and enhances cisplatin sensitivity in vitro

The kallikrein-related peptidase 10 (KLK10) gene has tumor-suppressive function in various types of human cancer. However, previous studies showed that KLK10 also acts as an oncogene and is upregulated in gastrointestinal tumors. The role of KLK10 in human esophageal cancer (EC) remains unclear. In the present study, the expression of KLK10 in human esophageal and non-esophageal cancer tissues was investigated by immunohistochemistry. Quantitative RT-PCR and western blot analysis were utilized to detect KLK10 mRNA and protein expression in human esophageal cancer cell lines (TE-1 and Eca-109). Small interference RNA was utilized to specifically knockdown KLK10 expression in Eca-109 and TE-1 cells. Cell proliferation, cell cycle analysis as well as CDDP-dependent apoptosis were determined using a CCK-8 assay and flow cytometry. The results showed that, KLK10 was positive in 67 out of 83 (80.72%) human EC and positive in 3 out of 11 (27.27%) normal tissues (P=0.001). The present study indicated that KLK10 potentially plays a crucial role in Eca-109 cell growth. Additionally, the downregulation of KLK10 induced S-phase arrest and promoted cisplatin-induced apoptosis. The resutls of the present study suggested that KLK10 is a promising novel marker for the diagnostic and therapeutic target of esophageal cancer.

Interaction with CCNH/CDK7 facilitates CtBP2 promoting esophageal squamous cell carcinoma (ESCC) metastasis via upregulating epithelial-mesenchymal transition (EMT) progression

CtBP2, as a transcriptional corepressor of epithelial-specific genes, has been reported to promote tumor due to upregulating epithelial-mesenchymal transition (EMT) in cancer cells. CtBP2 was also demonstrated to contribute to the proliferation of esophageal squamous cell carcinoma (ESCC) cells through a negative transcriptional regulation of p16(INK4A). In this study, for the first time, we reported that CtBP2 expression, along with CCNH/CDK7, was higher in ESCC tissues with lymph node metastases than in those without lymph node metastases. Moreover, both CtBP2 and CCNH/CDK7 were positively correlated with E-cadherin, tumor grade, and tumor metastasis. However, the concrete mechanism of CtBP2's role in enhancing ESCC migration remains incompletely understood. We confirmed that CCNH/CDK7 could directly interact with CtBP2 in ESCC cells in vivo and in vitro. Furthermore, our data demonstrate for the first time that CtBP2 enhanced the migration of ESCC cells in a CCNH/CDK7-dependent manner. Our results indicated that CCNH/CDK7-CtBP2 axis may augment ESCC cell migration, and targeting the interaction of both may provide a novel therapeutic target of ESCC.