Correlation Between Positive HER-2 Breast Cancer Stem Cells And Drug Resistance Of Breast Cancer MDA-MB-468 Cells

Objective:To investigate the correlation between HER-2 positive breast cancer drug resistance and breast cancer stem cells,It provides experimental basis for clinical individualized treatment and disease prognosis of breast cancer patients.Methods:Breast cancer cell with weak positive HER-2(MDA-MB-468)were divided into untreated and taxol-treated groups,Taxol-resistant breast cancer cell lines(MDA-MB-468/Taxol)were obtained by continuous induction with low concentration and dosage,MTT assay was used to determine the survival rate of the two groups,Flow cytometry was used to detect the HER-2 expression between the two groups,Breast cancer microspheres were enriched by microsphere culture,RT-PCR was used to detect the expression of Oct4 gene in the two groups,Aldefluor Assay was used to determine the expression rate of ALDH1 in both groups of cells.Results:1.Drug resistant breast cancer cells(MDA-MB-468/Taxol)were successfully obtained after 14 days of taxol pretreatment,MTT assay showed that the survival rate of the taxol-treated group was significantly higher than that of the untreated group when exposed to taxol again under the same conditions,The difference was statistically significant(p<0.01).2.Flow cytometry detected that HER-2 expression rates in untreated group and paclitaxel-treated group at different concentrations(2nM?5nM,10nM,20nM,50nM and 100nM)were 32.2%,39.4%,51.4%,65.6%and 66.7%,respectively,showing a gradually increasing trend.3.After 7 days of cell suspension culture,breast cancer microspheres were formed.The number of microspheres in the untreated group and the taxol-treated group with different concentrations(5nM and lOnM)were 29,65 and 48,respectively.The number of microspheres in the taxol-treated group was increased,there was a statistical difference(p<0.05).4.RT-PCR results showed that compared with the untreated group,the expression of dry cancer gene Oct4 was significantly increased in the taxol-treated group.5.The Aldefluor Assay experiment showed that the expression rates of ALDH1 in the untreated group and taxol-treated group in the control group were both 0.1%,while the expression rates in the untreated group and taxol-treated group were 0.2%and 0.6%,respectively,indicating that the proportion of breast cancer stem cells in taxol-resistant cells increased.Conclusion:1.The breast cancer cells with high HER-2 expression are taxol-resistant2.The high expression of HER-2 in breast cancer drug-resistant cells has the stem cell-like characteristics of higher microsphere formation ability and stem cell marker expression ability,which is the main reason of mediating chemotherapy resistanced.