Breast cancer resistance protein （Bcrp） and the testis--an unexpected turn of events  

睾丸中的乳腺癌耐药蛋白一些意想不到的发现

作　　者：Xiaojing Qiin Yan-Ho Cheng Dolores D Mruk C Yan Cheng 

机构地区：[1]The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, NY 10065, USA [2]Department of Anatomy, Histology and Embryology, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China and [3]Richmond University Medical Center, Staten Island, NY 10301, USA

出　　处：《Asian Journal of Andrology》2013年第4期455-460,I0006,共7页亚洲男性学杂志（英文版）

摘　　要：Breast cancer resistance protein （Bcrp） is an ATP-dependent efflux drug transporter. It has a diverse spectrum of hydrophilic and hydrophobic substrates ranging from anticancer, antiviral and antihypertensive drugs, to organic anions, antibiotics, phytoestrogens （e.g., genistein, daidzein, coumestrol）, xenoestrogens and steroids （e.g., dehydroepiandrosterone sulfate）. Bcrp is an integral membrane protein in cancer and normal cells within multiple organs （e.g., brain, placenta, intestine and testis） that maintains cellular homeostasis by extruding drugs and harmful substances from the inside of cells. In the brain, Bcrp is a major component of the blood- brain barrier located on endothelial cells near tight junctions （TJs）. However, Bcrp is absent at the Sertoli cell blood-testis barrier （BTB）; instead, it is localized almost exclusively to the endothelial TJ in microvessels in the interstitium and the peritubular myoid cells in the tunica propria. Recent studies have shown that Bcrp is also expressed stage specifically and spatiotemporally by Sertoli and germ cells in the seminiferous epithelium of rat testes, limited only to a testis-specific cell adhesion ultrastructure known as the apical ectoplasmic specialisation （ES） in stage VI-early VIII tubules. These findings suggest that Bcrp is equipped by late spermatids and Sertoli cells to protect late-stage spermatids completing spermiogenesis. Furthermore, Bcrp was found to be associated with F （filamentous）-actin and several actin regulatory proteins at the apical ES and might be involved in the organisation of actin filaments at the apical ES in stage VII-VIII tubules. These findings will be carefully evaluated in this brief review.Breast cancer resistance protein （Bcrp） is an ATP-dependent efflux drug transporter. It has a diverse spectrum of hydrophilic and hydrophobic substrates ranging from anticancer, antiviral and antihypertensive drugs, to organic anions, antibiotics, phytoestrogens （e.g., genistein, daidzein, coumestrol）, xenoestrogens and steroids （e.g., dehydroepiandrosterone sulfate）. Bcrp is an integral membrane protein in cancer and normal cells within multiple organs （e.g., brain, placenta, intestine and testis） that maintains cellular homeostasis by extruding drugs and harmful substances from the inside of cells. In the brain, Bcrp is a major component of the blood- brain barrier located on endothelial cells near tight junctions （TJs）. However, Bcrp is absent at the Sertoli cell blood-testis barrier （BTB）; instead, it is localized almost exclusively to the endothelial TJ in microvessels in the interstitium and the peritubular myoid cells in the tunica propria. Recent studies have shown that Bcrp is also expressed stage specifically and spatiotemporally by Sertoli and germ cells in the seminiferous epithelium of rat testes, limited only to a testis-specific cell adhesion ultrastructure known as the apical ectoplasmic specialisation （ES） in stage VI-early VIII tubules. These findings suggest that Bcrp is equipped by late spermatids and Sertoli cells to protect late-stage spermatids completing spermiogenesis. Furthermore, Bcrp was found to be associated with F （filamentous）-actin and several actin regulatory proteins at the apical ES and might be involved in the organisation of actin filaments at the apical ES in stage VII-VIII tubules. These findings will be carefully evaluated in this brief review.

关 键 词：actin filaments breast cancer resistant protein ectoplasmic specialisation effux drugtransporter germ cells Sertoli cells SPERMATIDS SPERMATOGENESIS SPERMIOGENESIS TESTIS 

分 类 号：R[医药卫生]