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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.

Aim To explore the effect of miR-296-5p on the metastasis of nasopharyngeal carcinoma (NPC) cells and investigate the underlying mechanism. Methods The expressions of miR-296-5p in NPC tissues and cells were determined using GSE32920 database analysis and real-time PCR and miRNA microarray assays. An miR-296-5p mimic and inhibitor were transfected into NPC cells. Then, immunofluorescence imaging, scratch wound-healing, transwell migration and invasion assays were used to observe the effects of miR-296-5p on cell metastasis and invasion. Real-time PCR and western blotting were carried out to detect the expressions of genes and proteins related to epithelial–mesenchymal transition (EMT). A dual luciferase reporter assay was used to identify whether TGF-β is the target gene of miR-296-5p. Finally, TGF-β expression plasmids were transfected into NPC cells to verify the role of TGF-β in the miR-296-5p-mediated inhibition of nasopharyngeal carcinoma cell metastasis. Results Our results show that miR-296-5p inhibits the migratory and invasive capacities of NPC cells by targeting TGF-β, which suppresses EMT. Importantly, the miR-296-5p level was significantly lower in human NPC tissues than in adjacent normal tissues. It also negatively correlated with TGF-β and was significantly associated with the lymph node metastasis of patients with NPC. Conclusions Our findings show that miR-296-5p represses the EMT-related metastasis of NPC by targeting TGF-β. This provides new insight into the role of miR-296-5p in regulating NPC metastasis and invasiveness.

Although fish consumption or omega-3 intake is associated with cardio- cerebrovascular disease including stroke, their correlation is still controversial. Therefore, this meta-analysis is to identify the relationship between the risk of stroke and fish consumption or omega-3 intake.We searched the PubMed, EMBASE and Cochrane Library databases as of May 2019. Multivariateadjusted risk ratios (RRs) with 95% confidence interval (CI) for stroke in different level intake of fish or Longchain omega-3 polyunsaturated fatty acids (LC ω3-PUFAs) were pooled using a random-effects meta-analysis. A dose-response analysis was conducted with the 2-stage generalized least-squares trend program.Our meta-analysis identified a total of 17 prospective cohort studies including 14986 strokes events in 672711 individuals. Meta-analysis revealed that the higher fish consumption was significantly associated with lower risk of stroke (RR=0.871, 95% CI: 0.779-0.975, p=0.016), especially with ischemic stroke (RR=0.808, 95% CI: 0.696- 0.937, p=0.005). Meantime, the combined RR of total stroke was 0.859 (95% CI: 0.769-0.959, p=0.007) for the highest versus lowest intake of LC ω3-PUFAs, and stratification analysis showed that higher LC ω3-PUFAs intake was associated with reduced stroke risk in women (RR=0.793, 95% CI: 0.706-0.891, p=0.000) but not in men. In addition, the dose-response analysis showed fish consumption with 1000g per month and LC ω3-PUFAs intake with 0.5g per month was associated with 17.3% (RR=0.927, 95% CI: 0.83-0.98) and 14% (RR=0.86, 95% CI: 0.78-0.95) lower risk of stroke, respectively.Both fish consumption and LC ω3-PUFAs intake were negatively associated with the risk of stroke, especially in women, which suggest that increased intake of fishery products and LC ω3-PUFAs may benefit primary prevention of stroke.