ABSTRACT
Objective: The in vitro treatment of tumor cells with platelet [Plt] causes inhibition of tumor cell growth, although mechanism of this effect is not clear yet. Induction of apoptosis has been proposed as a mechanism of Plt effects on tumor cells. The purpose of this study was to clarify the role of Plts and Plt-derived components in the induction of apoptosis in the blood mononuclear cells of patients with leukemia
Materials and Methods: In this experimental study, peripheral blood mononuclear cells [PBMCs] were isolated from whole blood of five patients with childhood B-precursor acute lymphoblastic leukemia [pre-B ALL] and encountered with Plts, Plt-derived microparticles [Plt-MPs] as well as purified soluble CD40L [sCD40L]. After 48 hours of co-culture, the anti-cancer activity of the aforementioned factors was surveyed using examination of apoptosis markers of the cells including active caspase-3 and CD95 using ELISA and flow cytometer techniques, respectively. Additionally, staining of the cells with 7-Aminoactinomycin D [7-AAD] was evaluated by flow cytometer technique. Trypan blue exclusion test and WST-1 method were also used to compare the death/survival status of the cells
Results: Levels of CD95 and caspase-3 were significantly increased in the all treated groups [P<0.05]. On the other hand, trypan blue, 7-AAD and WST-1 methods showed significantly lower number of the live cells in the treated groups [P<0.05]
Conclusion: This study can show the ability of Plts, Plt-MPs and sCD40L for the induction of apoptosis in PBMCs of pre-B-ALL patients. Further studies are necessary to elucidate the different effects of platelets on cancer cells in vitro and in vivo