Specific SiRNA Targeting Receptor For Advanced Glycation End Products (RAGE) Decreases Proliferation In Human Breast Cancer

Background:Receptor for Advanced Glycation End Products (RAGE) is overexpressed in various human cancers; however, its role in breast cancer development and proliferation is still unclear.Objective:The objective of this study was to investigate the effect of receptor for advanced glycation end products (RAGE) knock down through silencing RNA on the proliferation and biological behavior change of breast cancer.Methods:This study was divided into two parts:in vitro and in vivo. In vitro study was accomplished through breast cancer cell lines MDA-MB-231(triple negative), SK-Br-3(HER2positive) and MCF-7(estrogen receptor positive). RAGE siRNA was used to knock down RAGE gene in the three cell lines. qPCR and western blot were used to investigate the expression of RAGE, NF-kB p65, Cyclin D1and PCNA. MTT and cell cycle analysis were used to investigate the effect of RAGE knocked on cell proliferation and apoptosis. On the other hand, in vivo study was accomplished through21mice which were divided into six groups: RAGE siRNA group, RAGE siRNA+Doxorubicin group, Negative RNA+Doxorubicin group, Doxorubicin group, Negative RNA group and Blank control group. Traditional caliber calculation, optical imaging (BLI) and MRI were used to monitor the tumor growth in the xenografted nude mice. Subsequently, immunohistochemistry (IHC) was performed and the expression of RAGE, PCNA, CyclinDl and NF-κB p65was analyzed in the tumor samples.Result:We demonstrated that RAGE expression levels are correlated to the degree of severity of breast cancer. Furthermore, there was a decrease in the proliferation of all breast cancer cell lines combined by a decrease in tumor growth in the xenografted mice as a result of RAGE knock down. RAGE siRNA arrested cells in G1phase and inhibited DNA synthesis (p<0.05). Moreover, qRT-PCR, Western Blot and the immunohistochemistry results demonstrated that RAGE siRNA decreased the expression of transcriptional factor NF-κB p65as well as decreased the expression of cell proliferation markers PCNA and cyclinDl.Conclusion:RAGE is over expressed in all breast cancer sub-types specially the aggressive sub-type (triple negative). RAGE knock down decreased cell proliferation and significantly decreased tumor growth. However, RAGE knock down did not sensitize tumor to doxorubicin. These results indicate that targeting RAGE could be considered as a novel therapeutic strategy for the treatment of breast cancer.