Rubitecan, marketed by Supergen as Orathecin, is a promising oral treatment for solid melanoma, prostate, breast, ovarian, and other cancers, as well as leukemia. It is a derivative of camptothecin, a topoisomerase inhibitor known from Chinese Traditional Medicine. It selectively targets the critical S-stage of cellular reproduction – particularly in acidic environments, as in many cancer cells – relaxing DNA supercoiling and generating lethal breaks in the DNA. Due to insolubility, its biological delivery mechanism is not yet effective, and it has not been approved for clinical use.
https://www.sciencedirect.com/topics/medicine-and-dentistry/rubitecan
https://en.wikipedia.org/wiki/Rubitecan
https://en.wikipedia.org/wiki/Topoisomerase_inhibitor
https://en.wikipedia.org/wiki/Camptothecin#cite_note-Y.Pommier_2003-14
https://www.ncbi.nlm.nih.gov/pubmed/1995300
Rubitecan is a DNA topoisomerase I inhibitor. It inhibits DNA topoisomerase I and increases the fraction of supercoiled DNA in a cell-free assay in a concentration-dependent manner. Rubitecan inhibits the growth of A121 ovarian and H460 lung cancer cells (IC50s = 4 and 2 nM, respectively). It also inhibits the growth of doxorubicin-susceptible and -resistant MCF-7 breast cancer cells (IC50s = 2 and 3 nM, respectively). Rubitecan (4 mg/kg twice per week) reduces tumor growth in a U937 leukemia mouse xenograft model.
Semisynthetic camptothecin which inhibits DNA topoisomerase I. Prodrug of 9-aminocamptothecin. Antineoplastic.
ChEBI: A pyranoindolizinoquinoline that is camptothecin in which the hydrogen at position 9 has been replaced by a nitro group. It is a prodrug for 9-aminocamptothecin.
