LncRNA SNHG16 modulates paclitaxel resistance in breast cancer by regulating Let-7a-5p/DUSP7

Objective To investigate the effect of long chain non coding RNA (lncRNA) small nucleolar RNA host gene 6 (SNHG16) on paclitaxel (PTX) resistance in breast cancer and to understand its underlying mechanism, to lay a foundation for decreasing the PTX resistance in breast cancer treatment and improving the therapeutic quality for breast cancer patients. Methods PTX was used to induce the establishment of PTX resistant breast cancer cell lines; the control group (normal cultured MCF-7/PTX cells), si-NC group, si-SNHG16 group, si-SNHG16+anti miR-NC group, and si-SNHG16 +anti-Let-7a-5p group were set to compared the effect of SNHG16 on the PTX resistance in MCF-7 cells; MTT assay, Flow cytometry, and Transwell invasion assay were used to determine the PTX resistance, apoptosis, and invasion ability of MCF-7 cells in different groups, respectively; for further assess the effect of SNHG16 on the PTX resistance, nude mouse tumor transplantation experiment was used; and the potential mechanism of SNHG16 regulated the PTX resistance in MCF-7 cells was explored by double luciferase reporter gene detection method and gene silencing technology. Results The expression of SNHG16 gene and DUSP7 protein in MCF-7 cell line was the highest, and the expression of Let-7a-5p was the lowest compared with the various breast cancer cell lines (human breast epithelial cell line MCF-10A and human breast cancer cell lines MDA-MB-468 and MDA-MB-453) (P<0.05); PTX could increase the expression of SNHG16 gene and DUSP7 protein, and reduce the expression of Let-7a-5pin MCF-7 cell line (P<0.05); the results of cell experiment and nude mouse transplantation tumor experiment demonstrated that inhibiting the expression of SNHG16 gene could reduce the invasive ability and promote cell apoptosis of MCF-7/PTX cells (P<0.05), and inhibit tumor growth and reduce the PTX resistance in breast cancer transplantation models; simultaneous inhibition of Let-7a-5p and SNHG16 had a weakening effect in MCF-7/PTX cells (P<0.05). Double luciferase reporter gene detection and gene silencing technology demonstrated that inhibiting SNHG16 gene expression could increase the expression of Let-7a-5p and decrease the expression of DUSP7 (P<0.05); inhibiting the Let-7a-5p gene could increase the expression of DUSP7. Conclusions Inhibiting SNHG16 gene could upregulate Let-7a-5p expression and downregulate the expression of DUSP7 to inhibit MCF-7 cell invasion, promote MCF-7 cell apoptosis, and reduce the PTX resistance in MCF-7 cells and nude mouse tumor transplantation models, those data demonstrated that SNHG16-Let-7a-5p-DUSP7 axis maybe a potential therapeutic strategy for decreasing the PTX resistance in breast cancer in the future.