Construction Of Breast Cancer Cell Line MCF-7 Resistant To Adriamycin And Analysis Of Transcriptome Profiles

Objective:Breast cancer is one of the most common malignancies worldwide among female patients with the 1.5 million new diagnosis cases each year.The incidence rate annually increases by the rate of 6%,and gradually shows a trend of younger age.Adriamycin is the first line of clinical treatment of breast cancer,acquired resistance to ADR even multidrug resistance often occur in 30%-70%of patients with long-term use of ADR..Therefore,exploreing the molecular mechanism of the resistance to ADR and searching for prognostic or predictive biomarkers have significant effect to enhance the ADR treatment efficacy clinically.METHODS:Adriamycin resistance cell line of MCF-7(MCF-7/ADR)was established from MCF-7 by treating with high dose of ADR.Transcriptome sequencing was preformed to analyze differential gene expression,alternative splicing events andpredictionof new genes.Functional annotationofdifferentially expressed genes was based on thedatabase of KEGG,GO,COG,NR and Swiss-Prot,and then the sequencing results were verified by qRT-PCR.Results:MCF-7/ADR was successfully established,the drug resistance index was 310.09(P<0.001).Furthe toxicity experiments showed that MCF-7/ADR was also resistant to paclitaxel.According to the transcriptome sequencing results,3495 differentially expressed genes were identified between MCF-7/ADR andMCF-7 cell lines,among them 2029 genes were up-regulated and 1466 genes were down-regulated.Meanwhile,we noticed that the key genes of PI3K-AKT signal pathway and MAPK signal pathway were also significantly deregulated in transcriptome sequencing results.We deeply analyzed the most DEGs enriched 15 gene families then we selected the HOX family gene as the potential resistance genes to do further study.The qRT-PCR results showed that 24 genes of HOX family was up-regulated and 10 genes was down-regulated which has highly consistant with the results of transcriptome sequencing.We further explored the relationship between HOX gene family and drug resistance and found that HOXB2,HOXB5,HOXB13,HOXC8 and HOXDIO genes may involve in the resistance to Adriamycin.Conclusion:Transcriptome sequencing results reveals that HOX family genessuch as HOXB2,HOXB5,HOXB13,HOXC8 and HOXD10 may have close association with breast cancer cell MCF-7 doxorubicin resistance.Futher validation of HOX family genes shows that they may play important roles in other drug resistance during clinical treatment of breast cancer.Our study provides new promising therapeutic targets for breast cancer treatment,and validation in clinical patients is warranted.