RRD-251 is an Rb-Raf-1 interaction inhibitor that induces apoptosis in metastatic melanoma cells and synergizes with dacarbazine[1].

RRD-251, at concentrations ranging from 10-50 µM over 24 hours, effectively inhibits melanoma growth in vitro, as demonstrated through Cell Proliferation Assays conducted on SK-MEL-28, SK-MEL-5, and SK-MEL-2 cells. Additionally, at a concentration of 50 µM for 2 hours, it disrupts the interaction between Rb and Raf-1 and reduces Rb phosphorylation in non-small cell lung cancer cells, indicative of its ability to hinder cell cycle progression and promote apoptosis, as further evidenced by Western Blot Analysis which showed reduced phosphorylated-Rb levels. Furthermore, with a concentration of 50 µM over 18 hours, RRD-251 triggers apoptosis and at 20-50 µM for 4 hours, it induces cell cycle arrest in a dose-dependent manner in SK-MEL-28 and SK-MEL-5 cells, altering the expression of key proteins regulating the cell cycle and apoptosis, as highlighted in Apoptosis Analysis and Cell Cycle Analysis reports. These findings underscore RRD-251's potential as a therapeutic agent in the treatment of melanoma and non-small cell lung cancer by modifying crucial cellular processes.

RRD-251, administered at a dosage of 50 mg/kg intraperitoneally every other day for a duration of 14 days, exhibits anti-cancer effects in vivo, specifically targeting melanomas. This was observed in an animal model using 8-week-old female athymic nude mice implanted with SK-ME-28 xenografts. The result was a significant inhibition of SK-ME-28 xenograft growth in the mice.