DEATH PHENOTYPES INDUCED BY O-NAPHTOQUINONES IN Trypanosoma cruzi. ROLE OF THE ALDO- KETO REDUCTASE IN β-LAPACHONE MECHANISM OF ACTION

PATRICIA ANDREA GARAVAGLIA; MARIA FERNANDA RUBIO; MARC LAVERRIERE; LAURA MÓNICA TASSO; JOAQUÍN J. B. CANNATA; GABRIELA ANDREA GARCÍA

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

SAIC

Several ortho-naphthoquinones (o-NQs) have shown importanttrypanocidal activity against Trypanosoma cruzi, the ethiologicalagent of Chagas´ disease. We have previously demonstrated thatthe aldo-keto reductase from this parasite (TcAKR) reduces o-NQs,such as b-lapachone (b-lap) and 9,10-phenanthrenquinone (9,10-PQ), with concomitant reactive oxygen species (ROS) production.TcAKR activity and expression has been recently characterized intwo T. cruzi strains, CL and Nicaragua, showing that CL has 2-foldhigher TcAKR expression than Nicaragua. Here, we studied the trypanocidaleffect and the induction of several death phenotypes byb-lap and 9,10-PQ in epimastigotes of these two T. cruzi strains.CL was more resistant to both o-NQs than Nicaragua with IC50s of4.05 and 1.17 μM, respectively, suggesting TcAKR activity may notbe relevant in o-NQs activation in vivo. b-lap induced ROS, evaluatedwith H2DCF-DA probe, in both strains while 9,10-PQ only did itin CL. Staining with annexin V and propidium iodide (A/PI) showedthat both drugs induced an increase of A+/IP- (early apoptotic), A+/IP+ (late apoptotic or necrotic) and A-/IP+ (necrotic) cells only in CL.However, 4-fold monodansyl cadaverine (MDC) labelling was observedafter treatment in CL and Nicaragua suggesting autophagy maybe a common mechanism induced by these drugs. Altogether, theseresults highlight that death mechanisms used by these o-NQs differdepending on the combination of drug and T. cruzi strain evaluated.To study whether TcAKR participates in o-NQs activation, b-lapand 9,10-PQ trypanocidal effect was evaluated in TcAKR-overexpressingparasites. Only b-lap induced a greater ROS productionand showed a lower IC50 value in TcAKR-overexpressing epimastigotesthan in controls (5.1 μM and 7.9 μM, respectively). We concludethat TcAKR may be involved in b-lap activation through ROSgeneration, although TcAKR activity is not a determinant of susceptibilityin wild type T. cruzi strains.