Gastric cancer is the fifth most common malignancy in the world, with Eastern Asia as one of areas with the highest incidence rates. Trastuzumab, a HER2-targeting antibody, combined with chemotherapy has been successfully employed for the gastric cancer patients with HER2 overexpression/amplification. However, trastuzumab resistance is a major problem in clinical practice. Here we observed that the trastuzumab-resistant gastric cancer cell line NCI-N87/TR expressed high levels of epithelial-mesenchymal transition factors and demonstrated increased migration and invasion capability compared with NCI-N87 cells. Downregulated E-cadherin and increased N-cadherin, TGF-β, ZEB1, ZEB2, TWIST1, and Snail were detected in NCI-N87/TR cells. We also found that miR-200c was downregulated in NCI-N87/TR cells compared with parental cells NCI-87 by qRT-PCR. Treatment with TGF-β downregulated the expression of miR-200c and upregulated ZEB2, and significantly decreased the trastuzumab sensitivity of NCI-N87 cells. miR-200c restored trastuzumab sensitivity and inhibited migration and invasion through suppressing ZEB1 and ZEB2. In summary, TGF-β/ZEB2 axis plays an encouraging role in trastuzumab resistance of gastric cancer, while miR-200c overexpression downregulates ZEB1/ZEB2 and resensitizes drugs resistance. Our findings might provide a potential therapeutic strategy for trastuzumab resistance of gastric cancer.
Background/Aims: Small nucleolar RNAs (snoRNAs) play an important role in carcinogenesis. In this study, we identified a C/D box snoRNA, snord105b, and further investigated the function and mechanism of the snord105b in gastric cancer (GC). Methods: The expression level of snord105b in GC tissures, sera and cell lines were detected by qRT-PCR. Cell viability was assessed using MTS assay. Transwell and wound healing assay were performed to evaluate migration and invasion, and protein expression was examined by western blotting. ChIRP and MS analysis was used to seek for the special binding protein of snord105b. Results: The snord105b was upregulated and associated with tumor size, differentiation, and pathological stage in GC. Snord105b affected proliferation, migration and invasion in multiple GC cell lines. The oncoqenic activity of snord105b was also confirmed with in vivo data. Mechanistically, snord105b specifically bound to ALDOA and affected C-myc, which plays a key role in carcinogenesis and tumor development. Conclusion: Snord105b appears to be a novel oncogene and is clinically and functionally involved in the development of GC. Targeting snord105b and its pathway may provide new biomarkers or potential treatments for patients with GC.
Endometrial carcinoma (EC) is one of the most common malignancies of the female genital tract, although the mechanisms of EC initiation and development remain incompletely understood. In this study, we demonstrated that the noncoding RNA SNHG5 can inhibit the proliferation, migration, and invasion of EC cells by suppressing the expression of its putative target miR-25-3p. Overexpression of miR-25-3p significantly promoted the proliferation, migration, and invasion of EC cells. In addition, we showed that miR-25-3p represses the expression of BTG2 by directly binding to the 3′-UTR of BTG2 mRNA. Furthermore, increased miR-25-3p expression and decreased SNHG5 and BTG2 expression were observed in EC tissues, and the expression of SNHG5 was negatively correlated to that of miR-25-3p but positively correlated to that of BTG2. In summary, for the first time, we report that the SNHG5/miR-25-3p/BTG2 axis plays an important role in EC progression and is of great potential clinical significance for EC diagnosis and therapy.
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