RK-33

RK-33 is an RNA helicase inhibitor against DDX3, and inhibits its helicase activity. In Vitro: RK-33 shows inhibition of many kinds of cancer cells with IC₅₀ of 3-6 μM, while PC3 is much less sensitive to RK-33 (IC₅₀ >12 μM). RK-33 treatment causes a significant accumulation in the G1 phase for DU145 and LNCaP, although treatment with RK-33 causes only a moderate accumulation of the G1 phase for 22Rv1, and the treated cells have significantly reduced G2 phase. RK-33 treatment also causes 12 moderate G1 accumulation in 22Rv1^[1]. RK-33-loaded NPs demonstrate cytotoxicity to MCF-7 cells in a dose-dependent manner, while equivalent doses of empty NPs have no killing effect. The IC₅₀ value of 5% RK-33 loaded NPs is 49 μg/mL, and the IC₅₀ value of 10% RK-33 loaded NPs is 25 μg/mL^[2]. In Vivo: There is more cell death (pyknotic or condensed nuclei) admixed with fibrin and interstitial edema in the tumors from mice from the combination RK-33 and radiation group compared to the control or single treatment groups. The treatment combination of RK-33 and radiation has an advantage in reducing tumor proliferation^[1]. In the mice treated with RK-33-PLGA, RK-33 can be detected in the plasma (34 μg/mL) and liver (28 μg/g), but not lungs^[2].