Background <p>Curcumin is a polyphenolic compound from Curcuma longa that exhibits immunoregulatory and anti-cancer properties. It is formulated as nano-curcumin. Mesenchymal stem cells (MSCs) also show anticancer effects and can potentially activate resting immune cells. This study investigates the combined effects of nano-curcumin and adipose-derived mesenchymal stem cells (ASCs) on peripheral blood mononuclear cells (PBMCs) isolated from prostate cancer (PCa) patients.</p> Methods <p>ASCs were isolated and characterized. PBMCs were isolated from patients and co-cultured with and without ASCs in the presence of different concentrations of nano-curcumin to examine cell survival using the MTT assay. Based on the results of the MTT assay, selected concentrations of nano-curcumin were used to investigate apoptosis and cell subpopulations of PBMCs in co-culture with ASCs using apoptosis assay and flow cytometry.</p> Results <p>Nano-curcumin increased PBMC survival at concentrations of 3, 6, 12, 25, and 50 µM in co-culture with ASCs. In the absence of ASCs, a significant increase in PBMC survival was observed at concentrations of 6, 12, 25, 50, and100 µM. Concentrations of 6 and 12 µM caused a significant reduction in apoptosis. A concentration of 12 µM increased the number of CD3⁺CD4⁺ cells, and the number of CD3⁺CD8⁺ cells increased at concentrations of 6 and 25 µM. At a concentration of 25 µM, the number of CD45⁺CD19⁺ cells was significantly increased.</p> Conclusion <p>Nano-curcumin in combination with ASCs has the potential to affect immune cells, indicating its potential as a complementary therapy for use in cancer. Further research is required to confirm these findings.</p>