The Impact Of Mitochondrial DNA (mtDNA) D-Loop Region Mutations On Colorectal Cancer Chemosensitivity And The Interaction Between It With P53 Common Mutations Points

Objective:Colorectal cancer is a serious threat to the health of people. The related researchs shows that mitochondrial which supply energy as a major organelles has widespread mutation in colorectal cancer, and more mutations focusing on mitochondrial mutations (mtDNA) D-Loop have relationship with p53 mutation.The common p53 mutations in colorectal cancer was 175,248,273 three sites. Therefore, based on the relevance of this study we want to explore the impact of Mitochondrial DNA (mtDNA) D-Loop region mutations on colorectal cancer chemosensitivity and the interaction between it with P53 common mutations points.Methods:The first part of the experiment:The clinical specimens of patients with colorectal cancer were collected and divided into cancerous tissue and cancerous tissue, Total DNA were extracted from corresponding organizations and were amplified mitochondrial DNA D-loop region and common mutations 175,248,273 sites of the P53 gene in colon cancer related fragment. Then analysis the relationships between p53 gene mutation and D-loop mutations.The second part:H2O2 and p53 adenovirus were used to deal with Hct116-/-cell lines.the non-homologous sequences COII nuclear gene regions were detected in each group by RealtimPCR levels,TA cloning approach to detecte mitochondrial D-LOOP region mutation rate for each group. Apoptotic level of each group were detected by Calcein AM-PI and Annexiv-V.Result:Part Ⅰ:The mutation rate of mitochondrial D-LOOP region in Carcinoma is higher than the mutation rate of adjacent tissues. the mutation rate of carcinoma which has three 175,248,273 p53 mutation sites is higher than the other carcinoma that don’t have the three sites.carcinoma mutation rate mutation sites in 248 points higher than the other two sites.The second part:1,COII transcription levels of H2O2-induced HCT116-/-cells is lower than control cells, while their D-LOOP region mutation rate is higher.2, COII transcriptional level of the group which has p53 overexpression is higher than H2O2 induced group alone, while the D-LOOP region mutation rate is lowwer.3, Apoptosis rate of the oxidative damage to mitochondrial damage cells induced by H2O2 in the oxaliplatin group is lower than the control group.Conclusion:1, The mitochondrial mutations rate of D-LOOP cancer tissue is higher than the adjacent tissues.2, The mitochondrial mutations rate of D-LOOP in cancer tissue with p53 mutations is higher than that cancer tissue does’t have.3,175,248,273 locus mutation rate of mutation in cancer tissue 248 points higher than the other two sites.4, H2O2-induced HCT116-/-cells can lead to mitochondrial damage, as well as D-LOOP region mutation rate increased.; whereas overexpression of p53 is able to reduce the damage and mitochondrial D-LOOP region mutation rate.5,oxidative damage induced mitochondrial damage can enhance cells to chemotherapeutic drug resistance.