HEMIN INDUCES AUTOPHAGY IN LEUKEMIC ERYTHROBLAST CELL LINE?

SALASSA BN; MOOR F; VERGARA A; FADER CM

Buenos Aires

Congreso; Molecular mechanisms in cell signaling and gene expression. Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2013

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (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. This process has been associated with several physiologic processes as erythroid maturation. LC3 is a protein present in autophagosomal membrane, therefore is considered a bonafide marker of this structure. Our results indicate that in K562 cells, hemin (erythroid maturation inductor) produced an increased number and enlargement of GFP-LC3 positive vesicles labeled with lysotracker or DQ-BSA compared with others maturation inductors. Moreover, we have demonstrated that hemin induces mitochondria membrane depolarization. We have also shown in erythroblastic leukemic cells co-expressing RFP-LC3 and GFPRab11 (a multivesicular bodies marker) that hemin generates an enlarged vesicles labeled with both markers. Likewise, we have performed a western blot to detect the processing of LC3 protein upon hemin incubation. We have observed in this assay an increased total amount and a higher level of processed LC3. Taken together, our results suggest that hemin could induce mitophagy response in K562 cells, probably allowing an efficient and faster maturation.