Fosbretabulin disodium(CA 4DP; CA 4P) is a microtubule destabilizing drug, a type of vascular-targeting agent, a drug designed to damage the vasculature (blood vessels) of cancer tumors causing central necrosis.
IC50 Value: 4 nM [1]
Target: microtubule
in vitro: Cytotoxic IC(50) values of CA-4 in human bladder cancer cells were below 4 nM. Analyses of cell-cycle distribution showed CA-4 obviously induced G(2)-M phase arrest with sub-G(1) formation. The analyses of apoptosis showed that CA-4 induced caspase-3 activation and decreased BubR1 and Bub3 in cancer cells [1]. The enhanced apoptosis induced by dasatinib plus CA-4 was accompanied by a greater extent of mitochondrial depolarization, caspase-3 activation and PARP cleavage in HO-8910 cells. Furthermore, elevated expression of Mcl-1 led to a reduced apoptosis induced by dasatinib plus CA-4, highlighting that downregulated Mcl-1 was necessary for the potentiating effect of dasatinib to CA-4-triggered apoptosis [2].
in vivo: The increased anticancer efficacy of dasatinib combined with CA-4 was further validated in a human HO-8910 ovarian cancer xenograft model in nude mice [2]. There was a significant, concentration dependent increase in mean arterial blood pressure with a maximum increase of about 60% of the baseline MAP at 30 mg/kg of CA4P compared to the saline control. However, there was no significant increase in the cardiac troponin I level after CA4P injection [3].
Clinical trial: A phase II trial of fosbretabulin in advanced anaplastic thyroid carcinoma and correlation of baseline serum-soluble intracellular adhesion molecule-1 with outcome [4].

10-Deacetyl-7-xylosyl paclitaxel

10-Deacetyl-7-xylosyl paclitaxel is a Paclitaxel derivative with improved pharmacological features and higher water solubility.
IC50 value:
Target: Microtubule inhibitor
10-Deacetyl-7-xylosyl paclitaxel induced mitotic cell cycle arrest and apoptosis as measured by flow cytometry, DNA laddering, and transmission electron microscopy. Pro-apoptotic Bax and Bad protein expression was up-regulated and anti-apoptotic Bcl-2 and Bcl-XL expression down-regulated, which lead to a disturbance of the mitochondrial membrane permeability and to the activation of caspase-9. In turn, caspase-9 activated downstream caspases-3 and -6, but not caspase-8. Bid was also activated by caspase-3. Reversely, treatment with a caspase-10-specific inhibitor could not protect PC-3 cells from 7-xylosyl-10-deacetyl-paclitaxel-triggered apoptosis. Moreover, 7-xylosyl-10-deacetylpaclitaxel had no effect on the expression of CD95 and NF-kappaB proteins, indicating that apoptosis was induced through the mitochondrial-dependent pathway in PC-3 cells.