Anticancer effect of piperine, a black pepper compound, regulating apoptosis mediated through extracellular vesicles and cathepsin D in acute leukemia

Extracellular vesicles (EVs) contribute to tumorigenesis in acute leukemia, while natural compounds can counteract these EVs-mediated mechanisms. Piperine, a natural black pepper compound, exerts anticancer activity toward many cancer cells with minimal effect in normal PBMC cells via the apoptosis signaling pathway, a key programmed cell death pathway. The aim of this study was to investigate the involvement of EVs in piperine-induced apoptosis in acute leukemia. NB4 and MOLT-4 leukemic cell lines were treated with various concentrations of piperine. Cell viability, apoptosis, and cell cycle distribution were assessed using MTT assays and flow cytometry, respectively. Bioinformatic analysis was utilized to identify EV-related target proteins of piperine. RT-qPCR and Western blotting were performed to evaluate the expression of proapoptotic genes and proteins, respectively. Our findings demonstrated that piperine inhibited cell proliferation and induced apoptosis in both leukemic models. Cathepsin D (CTSD) has emerged as a piperine-responsive protein which was regulated apoptosis. Notably, EVs from piperine-treated leukemic cells upregulated CTSD and proapoptotic genes and proteins, Bax and caspase-3. These findings suggest that piperine modulates EV-mediated communication to promote apoptosis in acute leukemia. Interestingly, this work highlights the potential of piperine as a natural therapeutic agent targeting EV-mediated leukemic apoptosis.