Mitochondrial DNA Copy Number Changes In Lung Cancer And Colorectal Cancer Cell Lines

Background:In mitochondria,mitochondrial genomic DNA(mtDNA)plays a vital role in the continued stability of mitochondrial function and the energy supply of cellular metabolism [1].At present,mitochondria are widely considered to be important participants in the physical process of many lung cancers and tumors.More and more mtDNA mutations are found in clinical studies,and even widely considered to be an important correlation in the physical processes of many lung cancers and tumors.Participants,and the study is expected to make mitochondria a potential lung cancer microbial and chemical marker for monitoring the severity of lung cancer and tumor progression,stage of development,treatment response,and its prognosis.In order to further analyze and understand the potential function and role of mitochondria in lung cancer and malignant colorectal cancer cells,we comprehensively analyzed somatic mitochondrial methylation and mutations,including mitochondrial mtDNA copy number,sequence mutations and mtDNA methylation s level.Further research confirms the clear and comprehensive direct relationship between the changes in mtDNA and the treatment of lung cancer and malignant colorectal cancer,and provides data and theoretical support for further use of mtdDNA as an effective method and strategy for the diagnosis and early treatment of lung cancer and malignant colorectal cancer.Method:1.Select several lung cancer,colorectal cancer and normal cell lines,which are lung cancer cell lines(NCI-H460,NCI-H838,NCI-H1299,NCI-H446,A549,NCI-H226);colorectal cancer cell lines(HCT116,HT-29,DLD-1,SW620,SW480);normal cell lines(MRC-5),respectively,using the corresponding culture medium(due to differentcell types,many culture medium preparations are also different)placed in the incubator in suitable conditions to cultivate.Cells with stable cell state were selected for cell DNA extraction in batches(because the growth cycle and speed of each cell were different)for subsequent experimens.2.MtDNA mutations and methylation in colorectal cancer,lung cancer and normal cell lines were studied by whole genome sequencing and mtDNA methylation detection.3.Generate the sequence from the original data and compare it with the revised Cambridge reference sequence(RCRS),and then query the known mutation information from the databases such as MITOMAP and hmtdb.4.The mtDNA copy number of each cell line was measured by qPCR.Then,spsspss23.0 software was used to analyze the difference between the two groups of statistical data.The data was expressed as mean ± standard deviation.Single factor analysis was used to evaluate the statistical significance of the differences.P < 0.05 has significant statistical difference.Conclusion:1.MtDNA mutations in cancer cells Comparing the mtDNA mutations in cell lines with different malignant degrees,it was found that the mtDNA mutation level had nothing to do with the malignant degree.2.Study on coincident sites of missense mutations It was found that A13105 G and several other mutation sites exist in each cell line at the same time,but the number of haploids it participates in is relatively small,indicating that A13105 G may be an important mutation site in the study.3.Analysis of mitochondrial methylation From the methylation ratio,methylation type distribution,and methylation area distribution of each cell line,we can find that the level of mitochondrial methylation has nothing to do with the degree of cell malignancy.4.MtDNA copy number analysis Compared with normal cells,the mtDNA copy number of colorectal cancer and lungcancer cell lines seems to have an inverse U-shaped relationship with the degree of malignancy.However,the change of mtDNA copy number in lung cancer cells is significant,but it seems to have nothing to do with the degree of malignancy.