Study On The Biological Mechanism Of CD133 In The Occurrence And Development Of Breast Cancer

Objective: CD133 is one of tumor stem cell markers,plays an important role in tumor recurrence and metastasis,and is a potential therapeutic target for many cancers.However,the role of CD133 in regulating the biological function of breast cell carcinoma alone is unknown.Methods:(1)The expression of CD133 in 108 cases of breast cancer and its clinical correlation were analyzed by immunohistochemistry.(2)The expression of CD133 in breast cancer tissues and cells was detected by Western blot.(3)In vitro cultured human breast cancer cells MDA-MB-231 and MDA-MB-468,three RNA sequences of different interference targets for CD133 and one negative control were constructed.The MDA-MB-231 and MDA-MB-468 cells were infected with lentivirus,and the expression of CD133 protein in the transfected cells was verified by Western Blot,and the target sequence with the highest interference efficiency was screened out.(4)The proliferation potential of MDA-MB-231 and MDA-MB-468 cells was investigated by MTT and colony cloning assay after CD133 silencing.(5)The changes of invasion and migration ability of MDA-MB-231 and MDA-MB-468 cells after transfection were observed by cell scratch and Transwell assay.(6)Western blot assay was used to detect the effect of silencing CD133 gene on the expression of EMT-related protein in breast cancer cells.(7)Western blot assay was used to detect the effect of gene down-regulation on the expression of proteins related to Wnt/β-catenin signaling pathway in breast cancer cells.Results:(1)The expression of CD133 was positive in 72(66.7%)of 108 breast cancer tissue samples.The expression of CD133 was positively correlated with lymph node metastasis,TNM stage,distant metastasis,pathological differentiation and age,but had no significant relationship with tumor size.(2)The expression level of CD133 in breast cancer cells was significantly higher than that in normal human breast cells(P<0.05).the expression level in breast cancer tissue was significantly higher than that in normal breast tissue(P<0.05).(3)Green fluorescence was observed in MDA-MB-231 and MDA-MB-468 cells transfected with lentivirus under fluorescence inverted microscope,indicating that the target vector was transfected and expressed in MDA-MB-231 and MDA-MB-468 cells.Western Blot results showed that the expression of CD133 decreased after transfection,and CD133 silenced MDA-MB-231 and MDA-MB-468 cells were successfully constructed.(4)MTT and colony cloning experiments showed that the cell proliferation of Sh-CD133 group was significantly lower than that of Sh-NC and Control groups(P<0.05).The scratch and Transwell experiments showed that SH-CD133 could inhibit the invasion and migration of MDA-MB-231 and MDA-MB-468 cells(P<0.05).(5)CD133 gene silencing was associated with increased expression of EMT molecular marker E-cadherin and decreased expression of N-cadherin and Vimentin(P<0.05).(6)Silencing of CD133 gene inactivated the Wnt/β-catenin signaling pathway,decreased the levels of related proteins Wnt1,β-catenin,p-GSK-3β and Cyclin D1,and increased the levels of p-β-catenin.GSK-3βdid not change significantly(P<0.05).Conclusion: CD133 is one of the poor prognostic factors for breast cancer patients in breast cancer tissue and cell.Inhibiting CD133 expression of biological behavior that inhibits breast cancer cells.This process may be involved in the process of transformation(EMT)related to the Wnt/β-catenin.In conclusion,CD133 may promote the progress of breast cancer disease,making CD133 a potential target for breast cancer treatment.