RESUMEN
Beclin 1 is a key factor for initiation and regulation of autophagy, which is a cellular catabolic process involved in tumorigenesis. To investigate the role of alternative splicing of Beclin1 in the regulation of autophagy in leukemia cells, Beclin1 mRNA from 6 different types of cell lines and peripheral blood mononuclear cells from 2 healthy volunteers was reversely transcribed, subcloned, and screened for alternative splicing. New transcript variants were analyzed by DNA sequencing. A transcript variant of Beclin 1 gene carrying a deletion of exon 11, which encoded a C-terminal truncation of Beclin 1 isoform, was found. The alternative isoform was assessed by bioinformatics, immunoblotting and subcellular localization. The results showed that this variable transcript is generated by alternative 3' splicing, and its translational product displayed a reduced activity in induction of autophagy by starvation, indicating that the spliced isoform might function as a dominant negative modulator of autophagy. Our findings suggest that the alternative splicing of Beclin 1 might play important roles in leukemogenesis regulated by autophagy.
Asunto(s)
Empalme Alternativo/genética , Proteínas Reguladoras de la Apoptosis/genética , Autofagia/genética , Proteínas de la Membrana/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , ARN Mensajero/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Linfocitos B/metabolismo , Beclina-1 , Línea Celular , Línea Celular Tumoral , Exones/genética , Células HEK293 , Células HeLa , Humanos , Leucocitos Mononucleares/metabolismo , Proteínas de la Membrana/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismoRESUMEN
Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis. However, autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein, though the molecular mechanism remains elusive. Nevertheless, since it can induce cooperation with apoptosis and differentiation in response to autophagic signals, autophagy can be manipulated for a better therapy on acute myeloid leukemia.