Targeting glucosylceramide synthase downregulates expression of the multidrug resistance gene MDR1 and sensitizes breast carcinoma cells to anticancer drugs

• Published in: Breast cancer research and treatment Vol. 121; no. 3; pp. 591 - 599
• Main Authors: Sun, Yanlin, Zhang, Tingguo, Gao, Peng, Meng, Bin, Gao, Yongsheng, Wang, Xiao, Zhang, Jianping, Wang, Hao, Wu, Xiaojuan, Zheng, Wenxin, Zhou, Gengyin
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 01.06.2010; Springer US; Springer; Springer Nature B.V
• Subjects: Animals; Antimitotic agents; Antineoplastic agents; ATP-Binding Cassette, Sub-Family B, Member 1 - antagonists & inhibitors; Biological and medical sciences; Breast cancer; Breast Neoplasms - drug therapy; Cancer; Cancer research; Cancer therapies; Cell Line, Tumor; Chemotherapy; Drug resistance; Drug resistance in microorganisms; Drug Resistance, Multiple - genetics; Drug Resistance, Neoplasm - genetics; Drug therapy; Female; Gene expression; Gene therapy; Genetic aspects; Glucosylceramide synthase; Glucosyltransferases - antagonists & inhibitors; Gynecology. Andrology. Obstetrics; Health aspects; Humans; Mammary gland diseases; MDR1; Medical sciences; Medicine; Medicine & Public Health; Mice; Mice, Nude; multiple drug resistance; Nude mice; Oncology; P-glycoprotein; Preclinical Study; RNA; RNA Interference; RNAi; Rodents; Tumors; Xenograft Model Antitumor Assays; P-glycoprotein; RNAi; MDR1; Nude mice; Glucosylceramide synthase; Multidrug resistance; Antineoplastic agent; Breast disease; RNA interference; Targeting; Glycosyltransferases; P Glycoprotein; Ceramide glucosyltransferase; Breast carcinoma; Target; Multiple resistance; Cell; Drug; Treatment resistance; Enzyme; Transferases; Rodentia; Breast cancer; Malignant tumor; Gene expression; In vitro; Mammary gland diseases; Gene silencing; Vertebrata; Mammalia; Mouse; Animal; MDR-1 gene; Hexosyltransferases; Cancer
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-009-0513-z

Drug resistance in breast cancer remains a major cause for the failure of chemotherapy. Glucosylceramide synthase (GCS) plays an important role in multidrug resistance (MDR) in breast cancer. P-glycoprotein (P-gp) also confers a cross-resistance of many unrelated drugs. In this study, we studied the MDR effect and potential mechanisms of breast cancer after constructing permanent breast cancer cell lines with GCS knockout by using recombinant vectors targeting GCS (pSUPER-GCSshRNAs). The GCSshRNA stably transfected cells were successfully established and significant lower levels of GCS mRNA and protein expression were confirmed. In in vitro experiments, the GCSshRNA stably transfected cells showed a significantly reduced level of MDR1 and P-gp expression and decreased drug efflux ability. Reduced level of GCS expression conveyed a significant reversal of drug resistance by MTT assay and increased caspase-3 activity. In in vivo experiments by using nude mice with xenograft tumors, a significant inhibition of tumor growth was observed after comparing with the control group. Furthermore, enhanced response of chemotherapy was acquired by reduced expression of GCS as well as MDR1 in vivo. In conclusion, GCSshRNA could efficiently suppress GCS and MDR1 expression in vitro and in vivo and these findings may be used as one of the methods to reverse MDR in breast cancer.