| Objective:To explore the relationship between HER2 expression and taxol resistance and stem cell markers in breast cancer cells.Methods:Her2-positive breast cancer cells(SKBR-3)were cultured in vitro and divided into control group(untreated group)and taxol-treated group with different concentrations of taxol.Taxol-resistant breast cancer cell line(Taxol-resistant cell,TRC)was obtained by continuous induction with low concentration and dosage.Cell morphology and survival rate of the control group and the taxol-treated group with different concentrations were observed by inverted microscope.Cell survival rate was detected by MTT method,and HER2 expression level was detected by flow cytometry.The expression of oncogene OCT4 in each group was detected by reverse transcription-polymerase chain reaction(RT-PCR),the positive expression of OCT4 in 179 patients with invasive breast cancer was detected by immunohistochemistry,and the expressions of HER2 and OCT4 in the 4 groups were detected by Western blot.Results:(1)After 3 days of adherent culture,the cell survival rate was observed under the microscope,and the control group was significantly higher than the taxol treatment group.(2)The survival rate of taxol cells treated with different concentrations for 3 days was significantly different by MTT assay,and the survival rate of taxol cells in the control group was higher than that in the taxol group.With the increase of drug concentration,the cell survival rate showed a decreasing trend(P<0.05).(2)The results of flow cytometry showed that the control group and the different concentrations of taxol treatment group had different levels of HER2 expression.With the increase of drug concentration,the expression of HER2 showed an increasing trend(P<0.05).(4)The MTT results show that the survival rate of the parent cell line and the SKBR-3 Taxol-resistant cell(TRC)cell line after 4 days of treatment with different concentrations of taxol are different,especially at 5nM and 10nM concentrations,the survival rate of TRC is obvious higher than the parental cell line,after 5 days of taxol treatment,the survival rate of TRC at 5nM concentration was significantly higher than that of the parental cell line,with a statistically significant difference(P<0.01).(5)The results of reverse transcription polymerase chain reaction(RT-PCR)showed that the expression level of cancer stem gene OCT4 in the taxol treatment group was significantly increased,and showed an increasing trend with the increase of drug concentration.(6)Immunohistochemical results showed that the positive rate of OCT4 in the tissues of 179 breast cancer patients was 25.1%,and the expression rate of OCT4 in HER2 positive breast cancer tissues(25 cases)was 44.0%,indicating that the expression of OCT4 was correlated with HER2(P<0.05).(7)Western blot results showed that the expression of OCT4 was significantly reduced in the SKBR-3/shHER2 cell line that silenced HER2 expression,while the expression of OCT4 was significantly upregulated in MCF-7/HER2 overexpressing HER2.Conclusion:(1)The taxol resistance of SKBR-3 breast cancer cells is related to the expression of HER2.(2)The expression of stem cell-related marker OCT4 is closely related to the taxol resistance mechanism of SKBR-3 breast cancer cells,and its expression is related to the expression of HER2. |
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