Venetoclax used alone, or in combination with cladribine, changes the expression of apoptosis-regulating genes in chronic lymphocytic leukemia cells in vitro.

Background: Venetoclax (VEN) and cladribine (2-CdA) are active agents in the treatment of chronic lymphocytic leukemia (CLL), although their precise pro-apoptotic mechanisms in CLL cells remain unclear. However, in vitro studies suggest that these drugs may alter the expression of several proteins involved in apoptosis.

Objectives: The aim of the study was to evaluate the effect of VEN and 2-CdA, used individually and in combination, on the expression of apoptosis-related genes in CLL cells in vitro.

Material And Methods: Mononuclear cells were collected from peripheral blood of 40 previously untreated CLL patients. The expression of 17 apoptosis-related genes was assessed using nCounter NanoString technology before and after 48-h in vitro incubation with VEN, 2-CdA or their combination (VEN + 2-CdA).

Results: Venetoclax + 2-CdA had a stronger effect on all tested genes except BCL2 and PMAIP compared to VEN alone, and on BID, BIK, FADD, P53, and SMAD3 compared to 2-CdA alone.

Conclusions: Venetoclax and 2-CdA may exert their pro-apoptotic effects on CLL cells in vitro, at least in part, by stimulating the expression of several apoptosis-related genes. The antileukemic activity of VEN is further enhanced when combined with 2-CdA.