Effect Of Tumor Suppressor Factor RUNX3 On The Expression Of Apoptosis-Related Genes And Effect Of The Berberine On The Proliferation In Gastric Carcinoma Cells

Gastric cancer is one of the most common malignancies worldwide, especially in China, and ranks second in terms of global cancer-related mortality. Better defining the molecular pathogenesis of gastric cancer and exploring novel drug are thus urgently demanding tasks.The first part of this thesis is to investigate the effect of tumor-suppressor RUNX3 on the transcription of apoptosis-related genes bcl-2,bax,caspase-3, caspase-8,caspase-9 in human gastric carcinoma cells BGC823,and reveal the apoptosis molecular mechanism promoted by RUNX3. METHODS:The eukaryotic expression vector of human Runx3 gene pcDNA3.1-Runx3 was constructed. pcDNA3.1-Runx3 and blank vector pcDNA3.1 were transfected into BGC823 cells respectively. After 48 hours, the total mRNA and protein were acquired and the expression level of Runx3 was determined by RT-PCR and Western blot. Then,the mRNA and protein expression of apoptosis-related genes bcl-2, bax,caspase-3, caspase-8 and caspase-9 was determined by RT-PCR and Western blot.β-actin was used as a control. RESULTS : The eukaryotic expression vector pcDNA3.1-Runx3 was constructed successfully and transfected into BGC823 cells. RT-PCR and Western blot confirmed that Runx3 level was higher in pcDNA3.1-Runx3 transfected BGC823 cells than in blank vector-transfected cells( P<0.05). The expression level of Bcl-2 gene is lower in pcDNA3.1-Runx3 transfected BGC823 cells than in pcDNA3.1 transfected BGC823 cells,while the expression level of caspase3,caspase9 is higher in pcDNA3.1-Runx3- transfected BGC823 cells than in pcDNA3.1 -transfected BGC823 cells (P<0.05). CONCLUSIONS :RUNX3 can promote apoptosis of BGC823 cells by down-regulation the transcription of bcl-2 and up-regulation the transcription of caspase-3 ,caspase-9.Research indicates chemotherapy can add to both quantity and quality of life in a proportion of advanced gastric cancer. The use of chemotherapy in patients with gastric cancer has attracted great interest through the decades. Clinically,however, the toxicity of chemotherapy can cause much damage to normal cells, resulting in severe side effects, and thus limits their clinical efficacy. It become one of the key questions is how to kill cancer cells using chemotherapy without damaging normal cells. To reduce side effects, lots of oncologists have empirically developed several protocols of combination chemotherapy. Many studies aimed at finding drugs able to potentiate the anticancer effect of chemotherapy without increasing the serious side effects but were not been successful. During the last decades discoveries identified berberine possessing antineoplastic activity. In these studies, berberine was suggested to exert selective cytotoxic effects on tumour cells without adverse side effects on normal cells. However, the effects of berberine on human Gastric cancer cells still remain unclear. Since the second part of this thesis are to investigate the antitumor effect of bererine on human Gastric cancer cells and its molecular mechanisms possibly involved . our findings indicate berberine can inhibit tumour cell growth and proliferation measured using the MTT assay and Colony formation assay. our findings also indicate berberine can inhibite gastric tumour cells though inducing cellular senescence or apoptosis measured usingβ-Gal staining,Quantitative real-time PCR (QRT-PCR) and Western blotting. It may have therapeutic implications in gastric cancer.