. Author manuscript; available in PMC: 2017 Aug 23.

Published in final edited form as: Bioorg Med Chem Lett. 2014 May 6;24(14):3006–3013. doi: 10.1016/j.bmcl.2014.04.088

Table 1.

Inhibitors and stimulators of HR proteins

Small molecule compound	Target protein	Mechanism	Potency (EC₅₀) in vitro	Specificity in vitro	Cellular effect
	RAD51	Inhibits RAD51 binding to ssDNA	1–2 μM	N/A	N/A
Metatungstate (Na₆H₂W₁₂O₄₀) 2	MvRadA	Inhibits MvRadA binding to ssDNA and dsDNA	~2.5 μM	N/A	N/A
	RAD51	Stabilizes the RAD51-ssDNA filament	N/A	Yes	Induces resistance of human fibroblasts to cisplatin.
	RAD51	Disrupts RAD51 oligomerization	4:5–30 μM/(0.2–0.4 μM RAD51) 5 : 44 μM/(0.2–0.4 μM RAD51)	Yes yes	Sensitizes human cancer cells to mitomycin C
	RAD51	Disrupts RAD51 binding to BRCA2 and RAD51 oligomerization	N/A	yes	Inhibits of HR in human cells; increases the sensitivity of MCF7 to IR.
	RAD51	Disrupts RAD51 binding to DNA	27μM/1μM RAD51	yes	Increases cell sensitivity to cisplatin and mitomycin C
	RAD54	Binds to RAD54 and inactivates its ATPase by generating reactive oxygen species	16.5μM/(0.1μM RAD54)	yes	N/A
	BLM	Disrupts BLM binding to DNA	Helicase activity: 3μM/10nM; BM activity:50μM/10nM	No (also inhibits WRN in vitro)	Enhances the toxicity of aphidicolin and exerts antiproliferative effect in cells expressing BLM.
	WRN	Inhibits the helicase activity with a milder inhibition of the ATPase and exonuclease activity	10: 20 μM/1.2nM; 11:N/A	Yes	NSC617145 causes sensitization of FA and NHEJ-deficient cells to mitomycin C
	MRN	Inhibits Mre11 exonuclease activity and prevents MRN-dependent activation of ATM	12 μM	yes	Inhibits HR-mediated DNA repair in HEK293 cells

Note: MvRadA = Methanococcus voltae RadA