Changes In Gene Expression During The Passage Of HeLa Cells

HeLa cells are rapidly proliferating cervical cancer cells with infinite proliferation,which can be passed continuously without aging and death.However,we found that after long-term culture to 100 generations,HeLa cell morphology began to change and the cell growth slowed down.In order to investigate the "immortalization" or aging characteristics of HeLa cells after long-term culture,we started from the 35 generation of HeLa cells(the youngest generation we obtained),and continuously passed the culture to 125 generations,and selected 1 generation every 5 generations,a total of 19 different generations of HeLa cells were analyzed by RNA-Seq.Transcriptome data of 18 HeLa cells different from those of 35 generations were obtained.The results showed that:(1)With the increase of cell passage times,the number of differentially expressed genes also increased to varying degrees.(2)Compared with 35 generations of HeLa cells,the expression of senescence related genes such as CCND3 in 18 different generations of HeLa cells was up-regulated to varying degrees.(3)The expression of genes involved in cell signal transduction and regulation of cellular pathways,such as ECEL1,was down-regulated to varying degrees.(4)KEGG enrichment analysis showed that the differentially expressed genes were enriched in signaling pathways related to cell aging,such as NF-?B signaling pathway,PI3K-Akt signaling pathway and MAPK signaling pathway.Further analysis of the differentially expressed genes in these pathways showed that the expression of IL1 A and IL1 B genes in MAPK signaling pathways were up-regulated,and the up-regulated expression was most obvious in the 95 and 105 generation cells.(5)Most of the differentially expressed genes related to cellular basic metabolism,such as oxidative phosphorylation and ribosomal pathways,were down-regulated.Among them,the down-regulated expression of AC138811.2 gene related to ribosomal pathways was most obvious in the 115 and125 generation cells.To sum up,with the increase of successive generations of HeLa cells,the expression levels of genes related to cellular pathways and basic metabolism,which maintain the basic life process of cells,were decreased,while the expression levels of genes related to cell senescence were increased The results showed that HeLa cells showed certain aging characteristics with the increase of successive passage times.