MiRNA-296-5p promotes the sensitivity of nasopharyngeal carcinoma cells to cisplatin via targeted inhibition of STAT3/KLF4 signaling axis

Improving drug sensitivity is an important strategy in chemotherapy of cancer and accumulating evidence indicates that miRNAs are involved in the regulation of drug sensitivity, but the specific mechanism is still unclear. Our previous study has found that miR-296-5p was significantly downregulated in nasopharyngeal carcinoma (NPC). Here, we aim to explore whether miR-296-5p is involved in regulating cisplatin sensitivity in NPC by regulating STAT3/KLF4 signaling axis. The cell proliferation and clonogenic capacity of NPC cells were evaluated by CCK8 Assay and plate colony assay, respectively. The Annexin V-FITC staining kit was used to determine and quantify the apoptotic cells using flow cytometry. The drug efflux ability of NPC cells were determined by Rhodamine 123 efflux experiment. The expression of miR-296-5p, apoptosis-related genes and protein in NPC cell lines were detected by qPCR and Western blot, respectively. Animal study was used to evaluate the sensitivity of NPC cells to DDP treatment in vivo. Our results showed that elevated miR-296-5p expression obviously promoted the sensitivity of NPC cells to DDP by inhibiting cell proliferation and clonogenic capacity, and inducing apoptosis. In addition, we found that miR-296-5p inhibited the expression of STAT3 and KLF4 in NPC cells, while overexpression of exogenous STAT3 reversed miR-296-5p-mediated enhancement in cell death of DDP-treated NPC cells. In vivo studies further confirmed that miR-296-5p promotes the sensitivity of NPC cells to DDP treatment. miRNA-296-5p enhances the drug sensitivity of nasopharyngeal carcinoma cells to cisplatin via STAT3/KLF4 signaling pathway.

DHA inhibits invasion and metastasis in NSCLC cells by interfering with CCL18/STAT3 signaling pathway

Omega-3 has been proposed as an antitumor substance that suppresses the growth and metastasis of multiple types of tumor cells, including lung cancer, but the specific mechanisms involved remain obscure. Our previous studies showed that the expression of chemokine ligand 18 was related to the migration and metastasis of non-small cell lung cancer. Here, we aim to explore whether omega-3 inhibits invasion and metastasis of NSCLC by regulating the expression of CCL18. The expression of CCL18, metastasis- and epithelial-mesenchymal transition (EMT)-related genes at mRNA and protein levels in NSCLC cell lines were detected by RT-qPCR and Western blot, respectively. The metastatic and invasive capability of NSCLC cells were evaluated by scratch wound healing and Transwell assays, respectively. Our results showed that the level of CCL18 is positively associated with metastatic ability of NSCLC cells. Docosahexaenoic acid, an important long-chain, polyunsaturated omega-3 (n-3) fatty acid, significantly inhibited invasion and metastasis of NSCLC cells, and concomitantly downregulated the expression of metastasis- and EMT-related genes and p-STAT3 signaling pathway. Additionally, we found that DHA inhibited CCL18 expression in lung cancer cells, while overexpression of CCL18 effectively reversed DHA-mediated downregulation in the expression of metastasis- and EMT-related genes and p-STAT3 signaling as well as DHA-mediated inhibitory effect on metastasis and invasion of NSCLC cells. DHA inhibits NSCLC cell invasion and metastasis possibly through targeted inhibition of CCL18/ STAT3 signaling pathway and EMT process.