MiR‐5100 increases the cisplatin resistance of the lung cancer stem cells by inhibiting the Rab6

Abstract

Cisplatin-based chemotherapy is the most commonly used treatment regimen for lung cancer. Cancer stem cells (CSCs) are postulated to be important promoters of drug resistance. We previously found that miR-5100 is overexpressed in lung cancer, but it is unknown whether and how miR-5100 regulates cisplatin resistance. Here, we demonstrated that miR-5100 was significantly up-regulated in CD44 CD133 lung cancer stem cells (LCSCs) compared with non-CSCs. Additionally, over-expression of miR-5100 increased CSC properties, cell growth, and tumor sphere formation in lung cancer cell line A549 or H1299, and that miR-5100 inhibitor significantly increased sensitivity of LCSCs to cisplatin in vitro. Surprisingly, the combination with miR-5100 inhibitor significantly decreased the IC50 of LCSCs to cisplatin. Furthermore, miR-5100 increased CSC properties and cisplatin resistance by inhibiting Rab6, a direct target gene of miR-5100. We demonstrated that miR-5100 overexpression increases the cisplatin resistance of the LCSCs through the mitochondrial apoptosis pathway. In conclusion, our results suggest that miR-5100 increases the cisplatin resistance of the LCSCs by inhibiting the Rab6. This study provides novel insight into the regulation of LCSCs by miRNA.

Small GTPase RAB6 deficiency promotes alveolar progenitor cell renewal and attenuates PM2.5-induced lung injury and fibrosis

“…For PM2.5 injury, WT and RAB6 −/− AEC2 cells were exposed to PM2.5 (100 μg/ml) or saline for 48 h as we previously described 7 . For cell transfection, the RAB6 overexpression vector was constructed and transfected into AEC2 cells by Lipofectamine 2000 as we previously described 29 . For DDK1 protein treatment, WT and RAB6 −/− AEC2 cells were exposed to DKK1 protein (10 ng/ml) (ab205987, Abcam) or PBS for 48 h. For DKK1 inhibitor treatment, RAB6 overexpression (RAB6) and negative control (NC) AEC2 cells were exposed to DKK1 inhibitor (Gallocyanine, 5 μM) or PBS for 48 h.…”

miR‐155 increases stemness and decitabine resistance in triple‐negative breast cancer cells by inhibiting TSPAN5

“…miR‐155 mimics, miR‐155 inhibitor, TSPAN5‐siRNA, and pcDNA3.1‐TSPAN5 plasmids (lacking the 3′‐UTR) (RiboBio, China) were transfected into MDA‐231 and BT‐549 cells via Lipofectamine 3000 (Thermo Fisher Scientific) as previously described 18 . For reporter and target gene function analyses, miR‐155 mimics and vectors (psiCHECK‐TSPAN5, pcDNA3.1‐TSPAN5) were cotransfected into MDA‐231 and BT‐549 cells according to the manual of the transfection reagent used.…”

“…Immunophenotyping analysis was performed as previously described 18 . MDA‐231 or BT‐549 cells treated with or without miR‐155 (miR‐155 mimics and miR‐155 inhibitor) were resuspended in buffer and incubated with antibodies (FITC‐CD24, PE‐CD44, and corresponding isotype controls) for 30 minutes at 4°C (while protected from light).…”

“…A mammosphere-formation assay was performed as we previously described. 18 Briefly, cells were plated in a single-cell suspensions in ultra-low attachment plates (24-well plates) at a density of 100 cells/ well. Cells were grown in serum-free cell culture medium for 10 days.…”

“…Furthermore, miRNAs play a critical role in the differentiation and self‐renewal of CSCs 17 . For instance, miR‐5100 promotes the self‐renewal and cisplatin resistance of lung CSCs by targeting Ras‐related protein 6 18 …”