A-1165442 is primarily utilized in research settings, particularly in the study of cancer and cell biology. It functions as a potent and selective inhibitor of the anti-apoptotic protein Bcl-xL, which plays a critical role in regulating programmed cell death. By inhibiting Bcl-xL, this compound helps researchers investigate the mechanisms of apoptosis and its potential in cancer therapy. It is often used in laboratory experiments to understand how targeting Bcl-xL can induce cell death in cancer cells, making it a valuable tool for developing novel therapeutic strategies. Additionally, A-1165442 is employed in studies exploring drug resistance in cancer cells, as Bcl-xL is often implicated in the survival of resistant cell populations. Its application extends to preclinical models where it aids in evaluating the efficacy of Bcl-xL inhibition in treating various malignancies.