Caspase-8 knockdown suppresses apoptosis, while induces autophagy and chemo-sensitivity in non-small cell lung cancer cells.

PURPOSE: Drug resistance remains a major cause of relapse and therapeutic failure in non-small cell lung cancer (NSCLC). The purpose of this investigation is to explore the relationship between caspase-8 level and chemo-sensitivity, as well as its underlying mechanism in NSCLC cells. METHODS: NSCLC cell line, A549 cells was used to investigate the influence of caspase-8 on the biological behavior in vitro. The abundance of caspase-8 in A549 cells was manipulated by transfection lentivirus containing specific caspase-8 short hairpin RNA (sh-caspase-8) and caspase-8 overexpressed plasmid. Cell viability and the percentage of apoptotic cells was quantified using cell counting kit-8 (CCK-8) assay and flow cytometry following Annexin V-FITC/PI staining, respectively. The formation of acidic vesicle organelles (AVOs) was examined by acridine orange staining and visualized under a fluorescence microscope. The mRNA and protein levels of relative genes were determined by qRT-PCR and western blotting. RESULTS: Our results indicated that cells infected with sh-caspase-8 exhibited high knockdown efficiency. Knockdown of caspase-8 significantly reduced apoptosis of A549 cells. As evidenced by the decreased number of apoptotic cells and the reduction of Bcl-2/bax ratio. Interestingly, caspase-8 knockdown also enhanced autophagy in A549 cells. Additionally, knockdown of caspase-8 reduced the doxorubicin, carboplatin, cisplatin, and etoposide sensitivity towards A549 cells. CONCLUSION: In summary, our results revealed that knockdown of caspase-8 could promote cell growth and autophagy, while reduce chemo-sensitivity and apoptotic cell death. These finding suggest caspase-8 might serve as a potential target to improve the chemo-sensitivity for NSCLC patients in clinical setting.

In vitro and in vivo anti-diabetic activity of Swertia kouitchensis extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Swertia kouitchensis has long been used as a folk medicine to treat hepatitis and diabetes in central-western China. Therefore, this study was aimed to evaluate the anti-diabetic activity of the plant ethanol extract. MATERIALS AND METHODS: Firstly, the extract was tested for its inhibitory activity on α-amylase and α-glucosidase in vitro. Following that, insulin secretion test in NIT-1 cell was performed. Then, oral sucrose or starch tolerance test of the extract were carried out in normal mice. After that, acute effect of the extract was executed in normal and streptozotocin-induced (60 mg/kg) diabetic mice. Eventually, long term effect of the extract was performed in diabetic mice for 4 weeks. Oral glucose tolerance test and biochemical parameters were estimated at the end of the study. RESULTS: Swertia kouitchensis extract could remarkably inhibit the activity of α-amylase and α-glucosidase and stimulate insulin secretion in vitro. And also the extract displayed anti-hyperglycemic activity, improved antioxidant capacity, ameliorated the hyperlipidemia and carbohydrate metabolism in diabetic mice. CONCLUSIONS: Swertia kouitchensis exhibits considerable anti-diabetic activity and metabolic alterations in diabetic mice. These results provide a rationale for the use of Swertia kouitchensis to treat diabetes mellitus.