Increased Expression of TGF-β and IFN-γ in Peripheral Blood Mononuclear Cells (PBMCs) Cultured in Conditioned Medium (CM) of K562 Cell Culture.

In the present study, we investigated the effects of conditioned media (CM) collected from the cancer cell lines (K562, MCF-7, and HeLa) on peripheral blood mononuclear cells (PBMCs) isolated from the healthy human blood. The soluble factors in the CM are probably responsible for the differential mRNA expressions of Foxp3, Helios, Neuropilin- 1 (NRP-1), and glycoprotein A repetitions predominant (GARP), along with IFN-γ and TGF-β in PBMCs cultured with cancer cells CM. The PBMCs cultured with CM of K562 showed increased expression of Foxp3, Helios, NRP-1, GARP, IFN-γ, and TGF-β compared to PBMCs cultured with CM of MCF-7 and HeLa cells. In addition, the intracellular staining on PBMCs cultured with CM from cell lines were also evaluated for CD4, CD25, Foxp3, Helios, and NRP-1 by multicolor flow cytometry. The expression of CD4+CD25+Foxp3+, CD4+Helios+Foxp3+ and CD+NRP-1+Foxp3+ showed retarded cell population compared to control PBMCs. Our data suggest that soluble factors in CM of cancer cells may trigger the immune response in PBMCs resulting in a systematic response. Further research could lead to the identification of specific soluble factors that are involved in trafficking of cells into the immune cascades, which could be a safe and promising strategy for targeting human cancers.