Interfering HMGB3 release from cancer-associated fibroblasts by miR-200b represses chemoresistance and epithelial-mesenchymal transition of gastric cancer cells.

Background: Cancer-associated fibroblasts (CAFs) are vital components of gastric cancer (GC) microenvironments, which impact the aggressive characteristics of GC cells. The objective of this study is to evaluate the influence of High Mobility Group Box (HMGB) on CAF-related GC. Methods: The tissues of 10 GC patients who underwent surgery the Sanya Central Hospital of Hainan Province from July 2018 to July 2019 were collected for the clinical study. Moreover, the GC cell lines, including MGC-803, AGS, and SGC-7901, were used in vitro experiment. We investigated the molecular mechanism of the miR-200b/HMGB3 axis in affecting the chemoresistance and epithelial-mesenchymal transition (EMT) of GC cells induced by CAFs. Cell transfection, Cell Counting Kit-8 (CCK-8), Transwell assay, western blot, enzyme-linked immunosorbent assay (ELISA), and other experiments were employed. Results: We found that miR-200b was down-regulated, yet HMGB3 was up-regulated in CAF-related GC. The CAFs markedly promoted cisplatin (CDDP) resistance, proliferation, invasion, migration, and EMT of GC cells. Gain-assay of miR-200b demonstrated that miR-200b inhibited the HMGB3 release from CAFs. In-vivo experiments confirmed that the growth and EMT of GC cells co-cultured with CAF-miR-200b were significantly reduced. Furthermore, CAFs enhanced the activation of ERK, JNK, and the Wnt/ß-catenin pathways, and those pathways, as well as the malignant behaviors of GC cells, were obviously attenuated by miR-200b or HMGB3 silencing. Conclusions: Collectively, HMGB3 derived from CAFs is negatively regulated by miR-200b and promotes the malignant behaviors of GC cells.

Overexpression of miR-382 Sensitizes Hepatocellular Carcinoma Cells to γδ T Cells by Inhibiting the Expression of c-FLIP.

Human γδ T lymphocytes were reported to display anti-tumor effects against multiple cancers, including hepatocellular carcinoma (HCC). Aberrant expression of microRNAs (miRNAs) leads to a low response to immunotherapy. Thirty-five HCC tumor tissues and their adjacent healthy tissues were collected from patients with primary HCC who underwent tumor resection in the Third People's Hospital of Hainan Province, China. The purity of the resulting γδ T cells was identified by anti-γδ-T cell receptor-phycoerythrin (anti-γδ-TCR-PE) and anti-CD3-fluorescein isothiocyanate (anti-CD3-FITC) antibodies on flow cytometry. Human HCC cell lines HepG2 and PLC were cultured. We observed that ex vivo, expanded human γδ T cells were able to induce cell lysis of HCC. Furthermore, as miR-382 was observed to be downregulated in HCC tissues and cell lines, we found that overexpression of miR-382 increased the sensitivity of HCC cells to γδ T cells. We proved that mRNA of cellular FADD-like interleukin-1ß-converting enzyme-inhibitory protein (c-FLIP) was the target of miR-382. Inhibition of c-FLIP by miR-382 significantly promotes the cell lysis of HCC through strengthening the activation caspase 8 induced by γδ T cell treatment. In conclusion, overexpression of miR-382 promotes HCC cell lysis induced by γδ T cells through inhibiting the expression of c-FLIP.