ABSTRACT
Overexpression of cytokine-induced apoptosis inhibitor 1 (CIAPIN1) contributes to multidrug resistance (MDR) in breast cancer. This study aimed to evaluate the potential of CIAPIN1 gene silencing by RNA interference (RNAi) as a treatment for drug-resistant breast cancer and to investigate the effect of CIAPIN1 on the drug resistance of breast cancer in vivo. We used lentivirus-vector-based RNAi to knock down CIAPIN1 in nude mice bearing MDR breast cancer tumors and found that lentivirus-vector-mediated silencing of CIAPIN1 could efficiently and significantly inhibit tumor growth when combined with chemotherapy in vivo. Furthermore, Western blot analysis showed that both CIAPIN1 and P-glycoprotein expression were efficiently downregulated, and P53 was upregulated, after RNAi. Therefore, we concluded that lentivirus-vector-mediated RNAi targeting of CIAPIN1 is a potential approach to reverse MDR of breast cancer. In addition, CIAPIN1 may participate in MDR of breast cancer by regulating P-glycoprotein and P53 expression.
Subject(s)
Animals , Female , Humans , Antibiotics, Antineoplastic/therapeutic use , Breast Neoplasms/drug therapy , Doxorubicin/therapeutic use , Drug Resistance, Neoplasm/genetics , Gene Silencing , Intracellular Signaling Peptides and Proteins/genetics , Blotting, Western , Breast Neoplasms/genetics , Carcinoma/drug therapy , Carcinoma/genetics , Disease Models, Animal , Genes, MDR , Genetic Vectors/genetics , Growth Inhibitors/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Lentivirus/genetics , Mice, Inbred BALB C , Mice, Nude , ATP Binding Cassette Transporter, Subfamily B, Member 1/drug effects , RNA Interference , RNA, Small Interfering/genetics , /drug effectsABSTRACT
Ras-related, estrogen-regulated, and growth-inhibitory gene (RERG) is a novel gene that was first reported in breast cancer. However, the functions of RERG are largely unknown in other tumor types. In this study, RERG expression was analyzed in hepatocellular carcinomas of human patients using reverse transcriptase PCR analysis. In addition, the possible regulation of RERG expression by histone deacetyltransferases (HDACs) was studied in several cell lines. Interestingly, the expression of RERG gene was increased in hepatocellular carcinoma (HCC) of male patients (57.9%) but decreased in HCC of females (87.5%) comparison with paired peri-tumoral tissues. Moreover, RERG gene expression was increased in murine hepatoma Hepa1-6 cells, human breast tumor MDA-MB-231 cells, and mouse normal fibroblast NIH3T3 cells after treated by HDAC inhibitor, trichostatin A. Our results suggest that RERG may function in a gender-dependent manner in hepatic tumorigenesis and that the expression of this gene may be regulated by an HDAC-related signaling pathway.