Thrombin By Cutting Pten Expression Promote Transfer Mechanism Research On Lung Cancer Cell Growth

Thrombin has been shown to be a key regulator of hemostasis,thrombosis, inflammatory,angiogenesis and embryonic development in Physiology and Pathology. Studies havedemonstrated that thrombin is one of the key factors for cancer developing. Our previous studyshowed that thrombin promoted the growth of lung cancer and shortened life span oftumor-bearing nude mice.Thrombin causes a significant decrease in PTEN (phosphatase andtensin homolog deleted in chromosome10) protein levels. The PTEN gene, a tumor-suppressorgene, encodes a dual-specificity phosphatase with lipid and protein phosphatase activities andpromotes the developing and metastasis of tumor. This study is aimed to investigate thrombininduces depression of PTEN to promotes lung cancer cells Glc-82growth and metastasis in vitroand the mechanism.To evaluate the effect of thrombin on promoting cell cycle progression，proliferation andinhibiting apoptosis of lung cancer cells Glc-82in vitro and the mechanism. The effect ofthrombin on Glc-82cells proliferation was determined by Cell Counting Kit-8（CCK-8）assay.For cell cycle and cell apoptosis analysis, the cells were stained with propidium iodide (PI) orAnnexin-V/PI followed by monitoring on flow cytometer, respectively. Real-time fluorescentquantitation polymerase chain reaction was used to detect the level of PTEN mRNA. The proteinexpression level of PTEN， Skp2，p27kip1，p21WAF1and AKT phosphorylation were detected byWestern blotting assay. Thrombin (0.5U/ml and1.0U/ml) significantly promoted Glc-82cellproliferation (p<0.01). Thrombin (0.5U/ml) facilitated the cell cycle process from G1phase to Sphase and inhibited apoptosis. Thrombin markedly down-regulated the expression level ofPTEN、p27kip1，p21WAF1,up-regulated the Skp2expression and increased AKT phosphoralation.To elucidate further the possible effect of thrombin on cell growth and metastasis of lungcancer cells Glc-82in vitro and the mechanism thereof. we detected the effect of thrombin oncell cycle,apoptosis and migration in lung cancer cells Glc-82after PTEN silencing and themechanism. We found that thrombin promoted cell cycle progression and migration are involvedin the depression of PTEN. However, Thrombin showed no effect on Glc-82cells apoptosis. Wealso found that thrombin enhanced AKT phosphoralation,and inhibited the expression level ofp27kip1. Nevertheless, Thrombin markedly showed no effect on the expression level ofSkp2.Overexpression of PAR1favored thrombin to induce significantly depression of PTEN.Taken together, thrombin induced depression of PTEN to promote lung cancer cells Glc-82 growth and metastasis maybe through PI3K/AKT-dependent and independent signallingpathways.