A novel inhibitor of antiapoptotic BCL-2 proteins; a new promising anticancer drug candidate.
Mechanism of action
ABT‐263 exerts its senolytic activity in senescent tumor cells by inhibiting BCL‐XL's interaction with BAX. ABT‐263 is a BH3 mimetic that inhibits anti‐apoptotic BCL‐2 family proteins by impeding their ability to bind pro‐apoptotic proteins, such as BAK and BAX. BCL‐2 and BCL‐XL are the primary targets of ABT‐263 in cancer cells.
Pharmacokinetics
The pharmacokinetic profile of ABT-263 is characterized by low plasma clearance values and low volumes of distribution in mice, rats, dogs, and monkeys, with plasma elimination half-lives after i.v. Dose of 4.6 to 8.4 hours. Bioavailability after oral gavage was ～20% in all four species. Due to its low aqueous solubility, ABT-263 displays a prolonged dissolution rate-limited oral absorption. P.o. administration in lipid-based formulations, in which the compound is significantly more soluble, yields enhanced absorption with bioavailability near 50% and an oral elimination half-life of 8.9 hours in dogs[5].
in vitro
ABT-263 is structurally related to ABT-737; it is a disruptor of Bcl-2/Bcl-xL interactions with pro-apoptotic proteins. Overexpression of the prosurvival Bcl-2 family members is commonly associated with tumor maintenance, progression, and chemoresistance. [1] ABT-263 displays the protection afforded by overexpression of Bcl-2 or Bcl-xL with EC50 values of 60 nM and 20 nM, respectively. A wide range of cellular activity is observed with ABT-263 having a 50% growth inhibition (EC50) of 110 nM against the most sensitive line (H146), whereas its activity in the least sensitive line (H82) results in an EC50 at 22 μM. All four cell lines with EC50 values of <400 nM (H146, H889, H1963, and H1417) are also highly sensitive to ABT-737, and the two most resistant lines (H1048 and H82) are similarly resistant to ABT-263.
