Piper nigrum Has an Antitumor Effect Through Regulation of the Phosphatidylinositol 3-Kinase Signaling Pathway in a Murine Model of Acute Myeloid Leukemia.

The search for safer and more effective therapies for acute myeloid leukemia (AML) has intensified due to low response rates and resistance to current chemotherapy. The aim of this study was to evaluate the antitumor and immunomodulatory effects of Piper nigrum extract in a murine model of AML, with particular emphasis on its ability to modulate the phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/AKT/mTOR) signaling pathway. The chemical composition of the extract was characterized using advanced analytical techniques. In vitro assays were performed to evaluate cytotoxic and cytostatic effects, glucose consumption and ROS production, modulation of Gal-9 (galectin 9) and PD-L1 (programmed death-ligand 1), focusing on and relating it to the modulation of the (PI3K/AKT/mTOR) pathway. In vivo studies were performed using mice inoculated with DA-3/ER-GM cells to evaluate hematological parameters, survival, and immune response after P. nigrum treatment. P. nigrum extract demonstrated cytotoxic and cytostatic activity in vitro, characterized by a decrease in cell proliferation and survival possibly associated with modulation of the PI3K/AKT/mTOR pathway. In the murine AML model, treatment significantly reduced circulating blasts, improved hematological parameters, and prolonged survival. In addition, an increase in effector memory CD8+ T cells was observed, along with a reduction in plasma proinflammatory cytokine levels. Piper nigrum may represent a promising complementary therapeutic strategy for AML, acting as an antitumor and immunometabolic modulator. These findings suggest potential clinical applications of P. nigrum extract as an adjuvant or alternative therapy in the treatment of AML, warranting further preclinical and clinical investigation.