Circ_0078607 increases platinum drug sensitivity via miR-196b-5p/GAS7 axis in ovarian cancer.

Platinum-based chemotherapy is one of the predominant strategies for treating ovarian cancer (OC), however, platinum resistance greatly influences the therapeutic effect. Circular RNAs (circRNAs) have been found to participate in the pathogenesis of platinum resistance. Our aim was to explore the involvement of circ_0078607 in OC cell cisplatin (DDP) resistance and its potential mechanisms. Circ_0078607, miR-196b-5p, and growth arrest-specific 7 (GAS7) levels were assessed by qPCR. Circ_0078607 stability was assessed by ribonuclease R digestion and actinomycin D treatment. Cell viability of various conic of DDP treatment was measured by CCK-8. The cell proliferation was determined by CCK-8 and colony formation assay. Western blotting was performed for determining GAS7, ABCB1, CyclinD1 and Bcl-2 protein levels. The direct binding between miR-196b-5p and circ_0078607 or GAS7 was validated by dual-luciferase reporter and RIP assay. DDP resistance in vivo was evaluated in nude mice. Immunohistochemistry staining for detecting Ki67 expression in xenograft tumours. Circ_0078607 and GAS7 was down-regulated, but miR-196b-5p was up-regulated in OC samples and DDP-resistant cells. Overexpression of circ_0078607 inhibited DDP resistance, cell growth and induced apoptosis in DDP-resistant OC cells. Mechanistically, circ_0078607 sequestered miR-196b-5p to up-regulate GAS7. MiR-196b-5p mimics reversed circ_0078607 or GAS7 overexpression-mediated enhanced sensitivity. Finally, circ_0078607 improved the sensitivity of DDP in vivo. Circ_0078607 attenuates DDP resistance via miR-196b-5p/GAS7 axis, which highlights the therapeutic potential of circ_0078607 to counter DDP resistance in OC.

A novel antitumor peptide inhibits proliferation and migration and promotes apoptosis in glioma cells by regulating the MKK6/p38 signaling pathway.

Protein- or peptide-based therapeutics have emerged as an innovative strategy for the treatment of cancer. Our previous research demonstrated that tripartite motif 9 short isoform (TRIM9s) is a tumor suppressor in glioma. In this report, we investigated whether a new peptide derived from TRIM9s, named T9sP, inhibits glioma progression and determined the possible molecular mechanism. The CCK-8 proliferation assay was performed in LN229 and U251 glioma cells. The scratch-wound assay was used to determine the migration of the cells. Apoptosis was assessed by flow cytometry using Annexin V-FITC/PI double staining method. The relative protein expression levels were detected by immunoblot analysis. The cell-penetrating peptide TAT was fused with T9sP to form TAT-T9sP. TAT-T9sP efficiently penetrated through the cell membrane of both LN229 and U251 cells. TAT-T9sP inhibited proliferation and migration and promoted apoptosis of glioma cells. TAT-T9sP activated p38 signaling by upregulating MKK6, and a p38 inhibitor, SB203580, reversed the inhibitory effects of TAT-T9sP on glioma cells. These results indicated the potential of TAT-T9sP for the development of a new anti-glioma medicine.