Co-culture of platelets obtained from blood donors with cell lines Acute Lymphoblastic Leukemia

• Grant number: 12/23358-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2013
• Effective date (End): January 31, 2014
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Estela Maria Novak
• Grantee: Victor Ligori Figueiredo
• Host Institution: Hemocentro de São Paulo. Fundação Pró-Sangue. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

The administration of intensive chemotherapy in the phase of remission induction therapy in children diagnosed with acute lymphoblastic leukemia in childhood (ALL) includes several agents with different mechanisms of action. These drugs cause significant disturbances in hematopoiesis as thrombocytopenia. The contribution of platelets at this stage may be significant since they provide a membrane surface with abundant phospholipids in pro-coagulation. Moreover, when platelets become activated, they expose specific receptors with a higher affinity for coagulation factors V, VIII, IX, and X. However, some studies show that numerous blood transfusions to patients who undergo these results in a phenomenon that reflects the low rate of survival. These studies attribute this mortality immunomodulation caused by exposure to blood products. Other studies, however, associate the increase of angiogenic proteins such as VEGF, TGF beta, and PDGF progression LLA with decreased patient survival. In this regard, these studies demonstrated that when platelets are activated they release angiogenic growth factors (VEGF, PDGF, and TGFbeta) stored in their .alpha granules. In the process of collection and storage of platelets at the blood bank, platelets are exposed to various mechanical stimuli that may lead to its activation. Our preliminary results showed that longer storage of platelet concentrate (5 days) in the blood bank contributes to increased VEGF released into the plasma, while platelets stored for 1 day after collection, the largest concentration of VEGF was restricted to alpha granules within the platelet. This study will observe the effect of the release of VEGF, PDGF, and TGF-beta in the first, third, and fifth day of storage in the blood bank in angiogenesis and proliferation of Jurkat cells (acute lymphoblastic leukemia), and as the angiogenic growth factors located in the alpha, granules can affect angiogenesis and proliferation of tumor cells.(AU)