RAD51 Inhibitor B02 is a specific inhibitor of the human RAD51 recombinase (with an IC50 value of 27.4μM), and it has no inhibitory effect on the homologous RecA in Escherichia coli (with an IC50 > 250μM) [1]. RAD51 is usually overexpressed in cancer cells. RAD51 Inhibitor B02 can inhibit the binding of RAD51 to single-stranded DNA (ssDNA) and disrupt the binding of double-stranded DNA to RAD51/ssDNA filaments [2-3]. RAD51 Inhibitor B02 can be used to increase the anti-tumor activity of tumor-killing drugs [4].
In vitro, treatment with RAD51 Inhibitor B02 (10μM; 72h) enhanced the sensitivity of the human multiple myeloma cell line NCI-H929 (H929) to doxorubicin (DOX), reducing the IC50 of DOX by 8.4 times [5]. Pre-treatment with RAD51 Inhibitor B02 (5μM; pretreat 1h and 7-10 days) significantly increased the sensitivity of MDA-MB-231 cells to cisplatin while having no significant effect on cell viability, and the IC50 of cisplatin decreased by 4 times when used in combination [6].
In vivo, combined treatment with RAD51 Inhibitor B02 (50mg/kg; once every two days for 4 times; i.p.) and cisplatin significantly inhibited tumor growth in MDA-MB-231 xenograft mice [6]. Treatment with RAD51 Inhibitor B02 (50mg/kg; once every three days for 4 times; i.p.) could slightly reduce tumor growth in A375R xenograft melanoma mice [7].
References:
[1] Huang, F., Motlekar, N.A., Burgwin, C.M., et al. Identification of specific inhibitors of human RAD51recombinase using high-throughput screening. ACS Chem. Biol. 6(6), 628-635 (2011).
[2] King H O, Brend T, Payne H L, et al. RAD51 is a selective DNA repair target to radiosensitize glioma stem cells[J]. Stem cell reports, 2017, 8(1): 125-139.
[3] Huang, F., Mazina, O.M., Zentner, I.J., et al. Inhibition of homologous recombination in human cells by targeting RAD51 recombinase. J. Med. Chem. 55(7), 3011-3020 (2012).
[4] Ward A, Khanna K K, Wiegmans A P. Targeting homologous recombination, new pre-clinical and clinical therapeutic combinations inhibiting RAD51[J]. Cancer treatment reviews, 2015, 41(1): 35-45.
[5] Alagpulinsa D A, Ayyadevara S, Shmookler Reis R J. A small-molecule inhibitor of RAD51 reduces homologous recombination and sensitizes multiple myeloma cells to doxorubicin[J]. Frontiers in oncology, 2014, 4: 289.
[6] Huang F, Mazin A V. A small molecule inhibitor of human RAD51 potentiates breast cancer cell killing by therapeutic agents in mouse xenografts[J]. PloS one, 2014, 9(6): e100993.
[7] Makino E, Fröhlich L M, Sinnberg T, et al. Targeting Rad51 as a strategy for the treatment of melanoma cells resistant to MAPK pathway inhibition[J]. Cell Death & Disease, 2020, 11(7): 581.
RAD51 Inhibitor B02是一种人RAD51重组酶的特异性抑制剂(IC50值为27.4μM),对大肠杆菌中的同系物RecA没有抑制作用(IC50>250μM)[1]。RAD51在癌细胞中通常会过度表达。RAD51 Inhibitor B02可抑制RAD51与单链DNA(ssDNA)的结合,并破坏双链DNA与RAD51/ssDNA细丝的结合 [2-3]。RAD51 Inhibitor B02可用于增加肿瘤杀伤药物的抗肿瘤活性 [4]。
在体外,RAD51 Inhibitor B02(10μM; 72h)处理增强了人多发性骨髓瘤细胞系NCI-H929(H929)对阿霉素(DOX)的敏感性,使DOX的IC50降低了8.4倍 [5]。RAD51 Inhibitor B02(5μM; 预处理1h和7-10 days)处理显著增加了MDA-MB-231细胞对顺铂的敏感性而自身对细胞活力没有显著影响,联合使用下顺铂的IC50降低了4倍 [6]。
在体内,RAD51 Inhibitor B02(50mg/kg; 每两天一次,共4次; i.p.)和顺铂联合治疗显著抑制了MDA-MB-231异种移植小鼠的肿瘤生长 [6]。RAD51 Inhibitor B02(50mg/kg; 每三天一次,共4次; i.p.)治疗可较小程度地减少A375R异种移植黑色素瘤小鼠的肿瘤生长 [7]。
















