The Role Of PLA2G4A In Gastric Cancer And Its Correlation With The Prognosis

Gastric cancer is the second cause of global cancer mortality, accounting for more than700,000deaths annually. In our previous research, we found that PLA2was closely related to the proliferation of gastric cancer cells. cPLA2is the main effective subtype of PLA2, PLA2-IVA (PLA2G4A) is the most important one. cPLA2dependents on calcium, and the molecular weight is85KD, Its has two catalytic region and N terminal to regulate C2region, which participate the combine of phospholipid and CaIB. cPLA2hydrolyze Sn-2of phospholipid to generate Arachdonic Acid (AA), which is then transfer to other mediators of inflammation by different enzymes, such as cyclooxygenas以--PGE2; Lipoxygenases--LTs; P450--Hydroxyeicosatetraenoic Acid. All of these mediators participate in the normal cell transduction or the pathology of inflammation and immunity. The role of them in the initiation and progression of cancer have aroused reseacher’s interest these years. So we guess PLA2G4A,which is the upstream of Arachdonic Acid, has also play an important role in the initiation and progression of cancer. The axis of COX-2-PGE2is a very common pathway in colon cancer, they are upregulated in colon cancer, clinical datas shows that long time using NSAID, the hibitor of cyclooxygenase1(COX-1)and cyclooxygenase2(COX-2), can deduce40%of the initiation of colorectal tumors, and can prevent colorectum from FAP to colorectal cacner. There are few study of phospholipase A2-IVA (PLA2G4A) in gastric cancer, but cyclooxygenase2(COX-2) is a hotpot in gastric cancer, and it is upregulated in gastric cancer. So we hypothesized that cyclooxygenase2(COX-2) take effect by phospholipase A2-IVA (PLA2G4A) in gastric cancer. We totally have three parts, First:The Role of Down-Regulated Phospholipase A2-IVA (PLA2G4A) in Gastric Cancer Cell; Second:The Effect of Pyrrophenone on Gastric Gancer Gell; Third:The Expression of PLA2G4A in Gastric Cancer Tissues and its Correlation with Clinical Pathological Parameters and Prognosis. We hope Phospholipase A2-IVA (PLA2G4A) can become a new target for the treatment of gastric cancer. First PartThe Role of Down-Regulated Phospholipase A2-IVA (PLA2G4A) in Gastric Cancer CellObjective:To observe the effect of SiRNA on the proliferation, cycle, apoptosis, and mobile ability of gastric cancer cell SGC-7901.Methods:Culture10cell line regularly, screen the cell which is highly expressed PLA2-IVA (PLA2G4A) using RT-PCR and Western Blot. Construction small RNA interference fragment of phospholipase A2-IVA (PLA2G4A). Cells were transfected by lipo2000.CCK-8was used to detect the proliferation of SGC-7901. The cell cycle of SGC-7901was detected by Flow cytometry. Mobile ability was detected by wound healing test at24h,48h,72h.Results:SGC7901, MKN45high expression of phospholipase A2-IVA (PLA2G4A), SNU1, SNU5were suspension cells, the other cells were lower expression or no expression of phospholipase A2-IVA (PLA2G4A), so we choose SGC7901or MKN45to finish the experiment. The successful construction of phospholipase A2-IVA (PLA2G4A) siRNA; when phospholipase A2-IVA (PLA2G4A) was interference, cell proliferation has not changed. With the extension of time, the scratch test shows that interference group grew slower than the NC group. The interference group of cells arrest at S stage, S phase extension. Interference group of apoptosis is slightly more than NC group, but no statistical significance between the two group.Conclusion:Pyrrophenone can inhibit the growth and motile ability of SGC7901, and PLA2G4A is expected to become a new target for cancer therapy. Second PartThe Effect of Pyrrophenone on Gastric Gancer GellObjective:To observe the effect of Pyrrophenone on the proliferation, cycle, mobile ability and apoptosis of gastric cancer cell SGC-7901.Methods:Culture cell line regularly, CCK-8was used to detect the proliferation of SGC-7901, and calculating the ratio of inhibition. The cell cycle and apoptosis of SGC-7901was detected by Flow cytometry. Mobile ability was detected by wound healing test at24h,48h,72h.Results:The proliferation of gastric cancer cells were detected in6time points and different concentrations. With the extension of time and concentration, the proliferation of SGC-7901cells was decreased gradually, IC50is9.4nmol. Cell cycle test results show that:after using Pyrrophenone, S stage was prolonged, cell growth arrest at S stage. Cell scratches test shows that after using Pyrrophenone, the cell growth rate decreased significantly, thus we can get the conclusion:The molecule inhibitor Pyrrophenone of phospholipase A2-IVA (PLA2G4A) can inhibit the growth and motile ability of SGC7901. There was no obvious apoptosis between the two groups.Conclusion:Pyrrophenone can inhibit the growth and motile ability of SGC7901, and phospholipase A2-IVA (PLA2G4A) is expected to become a new target for cancer therapy.Third PartThe Expression of PLA2G4A in Gastric Cancer Tissues and its Correlation with Clinical Pathological Parameters and PrognosisObjective:To elucidated the expression and the role of PLA2-IVA (PLA2G4A) in gastric cancer, and the association of PLA2-IVA (PLA2G4A) with cyclooxygenase2(COX-2). Methods:mRNA expression of PLA2-IVA (PLA2G4A) and cyclooxygenase2(COX-2) in60pairs of fresh gastric tumors and corresponding adjacent non-cancerous mucosa was detected by using RT-PCR and immunohistochemistry was used to detect866gastric cancer patients.Results:Highly expression of PLA2-IVA (PLA2G4A) in non-cancerous gastric tissues than tumors, as opposite to the increased expression of cyclooxygenase2(COX-2). PLA2-IVA (PLA2G4A) was significantly associated with tumor size (P=0.003), tumor grade(P<0.001), intestinal type (P=0.003), T classification (P<0.001), N classification (P<0.001), and thereby TNM stage (P<0.001). PLA2G4A and cyclooxygenase2(COX-2) expression were both identified as independent prognostic factors. Reduced PLA2-IVA (PLA2G4A) and increased cyclooxygenase2(COX-2) expression was associated with unfavorable survival for patients with gastric cancer.Conclusion:PLA2-IVA (PLA2G4A) combined with COX-2might serve as a better indicator of the prognosis in gastric cancer patients.