Tubulysin D is one of the most potent derivatives among the tubulysins isolated from the myxobacterial species Archangium geophyra and Angiococcus disciformis. Tubulysin D is a novel tetrapeptide that displays potent antitumor activity and leads to cell cycle arrest and apoptosis by inhibiting tubulin polymerization with an IC50 of 1.7 μM[1]. Tubulysin displays extremely potent cytotoxic activity in mammalian cells, including multidrug-resistant cell lines, with IC50 values in the lower nanomolar range[2]. IC50: 1.7 μM (Tubulin)[1]
Tubulysin D has IC50s of 4.7 pM, 3.1 pM, 670 pM and 13 pM for HL60, HCT116, MCF7, A549 cell lines antiproliferative activity, respectively[1].
[1]. Shibue T, et al. Synthesis and biological evaluation of tubulysin D analogs related to stereoisomers of tubuvaline. Bioorg Med Chem Lett. 2011 Jan 1;21(1):431-4. [2]. Kubicek K, et al. The tubulin-bound structure of the antimitotic drug tubulysin. Angew Chem Int Ed Engl. 2010 Jun 28;49(28):4809-12.