Hemin Induces autophagy in leukemic erythroblast cell line

FADER C.M., VERGARA A.N., MOOR F., SALASSA B.N., COLOMBO M.I.

Mendoza

Encuentro; Reunión Anual SAIB; 2012

SAIB

Autophagy is a normal degradative pathway that involves the sequestration of cytoplasmic components and organelles in a vacuole called autophagosome which finally fuses with the lysosome to degrade the sequestered material.Autophagy has been associated with several physiologic processes as erythroid maturation.LC3isaproteinpresentinautophagosomalmembrane, therefore is considerate as a bonafide marker of this structure. Our results indicate that hemine (erythroid maturation inductor) produced an increased number and enlargement of GFP-LC3 positive vesicles labeled with lysotracker or DQ-BSA compared withothersmaturationinductors.Moreover,wehavedemonstrated in K562 cells incubated with hemin, an enlargement GFP-Lamp1 positive vesicles labeled with mitotracker. We have also shown in erythroblastic leukemic cells co-expressing RFP-LC3 and GFPRab11 (a multivesicular bodies marker) and incubated in the presence of hemin enlarged vesicles labeled with both markers.We have performed western blot analysis to detect the processing of LC3proteinuponheminincubation.Wehaveobservedinthisassay an increased total amount and a higher level of processed GFP- LC3.Takentogether,ourresultssuggestthathemincouldinducean autophagic response in K562 cells, probably allowing an efficient andfastermaturation.