Cell line-specific antileukemic effects of imipramine: apoptosis, reactive oxygen species modulation and cytokine responses in human acute promyelocytic leukemia and chronic myelogenous leukemia cells.

OBJECTIVE: Imipramine, a tricyclic antidepressant, has recently attracted interest due to its potential anticancer properties. This study investigated the antileukemic effects of imipramine in human leukemia cell lines, with particular emphasis on apoptosis induction, mitochondrial dysfunction, reactive oxygen species modulation, and cell cycle regulation. METHODS: Human acute promyelocytic (HL-60) and chronic myelogenous leukemia (K562) cells were treated with imipramine. Cell viability was assessed using the MTS assay. Apoptosis was analyzed by flow cytometry following FITC Annexin V and propidium iodide staining. Mitochondrial membrane potential, intracellular reactive oxygen species levels, gene expression (RT-qPCR), and protein expression (ELISA) were evaluated. Cell cycle distribution was determined by flow cytometric analysis. In addition, Semaphorin 3 A (SEMA3A) expression was examined. RESULTS: Imipramine induced dose- and time-dependent cytotoxic effects in both HL-60 and K562 cells. Imipramine significantly increased apoptotic cell populations, accompanied by mitochondrial dysfunction. SEMA3A expression was downregulated in HL-60 cells but unchanged in K562 cells. RT-qPCR analysis indicated limited, cell line–specific transcriptional modulation, characterized by significant BAK upregulation and CASP3 downregulation in HL-60 cells, while only non-significant upward trends were observed for apoptosis-related transcripts in K562 cells. Cell cycle analysis demonstrated S-phase accumulation together with reduced progression into mitosis, suggesting cell cycle arrest. CONCLUSION: Imipramine exhibits pronounced antileukemic activity through mitochondrial-dependent apoptotic mechanisms. These findings support the potential repurposing of imipramine as an anticancer agent and warrant further investigation into its therapeutic applicability.