Effect of soluble human PD-۱ expressingconstruct with tumor lysate on proliferation of tumor cells

Background: Today, targeting the inhibitory pathways in tumormicroenvironments has enhanced the function of the antitumoreffector cells and suppressed the function of inhibitoryimmune cells. In addition, using the source of tumor antigens,tumor lysate, can induce activation of T lymphocytes and influencetumor cell survival. In this study we evaluated the effectof applying recombinant soluble human Programmed cell deathprotein-۱ (rshPD-۱) expressing construct with tumor lysate ontumor cells.Materials and Methods: We designed and produced rshPD-۱expressing construct in pCDNA۳.۱ hygro+ plasmid. Tumor celllysate was prepared by freezing and thawing of MDA-MB-۲۳۱cells. MDA-MB-۲۳۱ cells were transected by rshPD-۱-plasmidand then stained with Carboxyfluorescein-succinimidyl-ester.Exhausted T cells and tumor lysate were added to transfectedcells and after ۲۴ hours, proliferation of MDA-MB-۲۳۱ cellswas evaluated by flow-cytometry method.Results: Proliferation of tumor cells in the transected tumorcells group and also in the transected cells/tumor cell lysategroup was significantly lower than in the control group.Conclusion: PD-۱/PD-L۱ interaction between T lymphocytesand tumor cells activates the mammalian target of rapamycin(mTOR) and induces proliferation of tumor cells. Blockadeof PD-۱/PD-L۱ interaction by secreted PD-۱ from transfectedcells, suppressed mTOR activation and also Treg and Th۱۷ celldifferentiation, which therefore reduced tumor cell proliferation.In addition, tumor cell lysate as the source of tumor associatedantigens, damage-associated molecular patterns andsoluble immunosuppressive factors can be uptake via macropinocytosisand processed into the MHC class II pathway and represented to toll-like receptors (TLRs). TLRs ligation onT cells results in T cell activation and expansion. Our studyshowed that the inhibitory function of secreted hPD-۱ by transfectedMDA-MB-۲۳۱ cell line along with tumor cell lysatecould decrease proliferation of MDA-MB-۲۳۱ cells. Therefore,this gene construct or its product could be used as a therapeuticagent in tumor environments.

کلیدواژه ها:

Programmed cell death protein-۱ ، gene construct ، tumorlysate ، proliferation ، MDA-MB-۲۳۱ cell