RESUMEN
UHMK1 (KIS) is a nuclear serine/threonine kinase that possesses a U2AF homology motif and phosphorylates and regulates the activity of the splicing factors SF1 and SF3b155. Mutations in these components of the spliceosome machinery have been recently implicated in leukemogenesis. The fact that UHMK1 regulates these factors suggests that UHMK1 might be involved in RNA processing and perhaps leukemogenesis. Here we analyzed UHMK1 expression in normal hematopoietic and leukemic cells as well as its function in leukemia cell line. In the normal hematopoietic compartment, markedly higher levels of transcripts were observed in differentiated lymphocytes (CD4+, CD8+ and CD19+) compared to the progenitor enriched subpopulation (CD34+) or leukemia cell lines. UHMK1 expression was upregulated in megakaryocytic-, monocytic- and granulocytic-induced differentiation of established leukemia cell lines and in erythrocytic-induced differentiation of CD34+ cells. No aberrant expression was observed in patient samples of myelodysplastic syndrome (MDS), acute myeloid (AML) or lymphoblastic (ALL) leukemia. Nonetheless, in MDS patients, increased levels of UHMK1 expression positively impacted event free and overall survival. Lentivirus mediated UHMK1 knockdown did not affect proliferation, cell cycle progression, apoptosis or migration of U937 leukemia cells, although UHMK1 silencing strikingly increased clonogenicity of these cells. Thus, our results suggest that UHMK1 plays a role in hematopoietic cell differentiation and suppression of autonomous clonal growth of leukemia cells.
Asunto(s)
Diferenciación Celular/genética , Hematopoyesis/genética , Células Madre Hematopoyéticas/fisiología , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas Serina-Treonina Quinasas/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Células K562 , Leucemia/genética , Leucemia/patología , Masculino , Persona de Mediana Edad , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/patología , Células U937 , Regulación hacia Arriba/genética , Adulto JovenRESUMEN
Dietary fat quality affects overall systemic parameters and produce hepatic accumulation of fat and inflammation (steatohepatitis). In this communication we have assessed how mouse liver nuclear phenotypes are influenced by diets containing 7% lipid prepared with lard, linseed oil or soybean oil for 32 weeks. Liver specimens were imprinted on glass slides, fixed and stained with DAPI. 3D confocal images were obtained and employed for the calculation of nuclear thickness, nuclear volume and DAPI-DNA intensity. Hepatocytes' nuclei could be classified as diploid A, diploid B, tetraploid and higher ploidy levels. Linseed oil in the diet resulted in increased frequency of diploid A (more compact) and less polyploidy, while lard caused increased volume and more polyploidy. Soybean oil produced intermediate nuclear sizes. The results suggest a high demand on liver physiology promoted by lard, which has a predominance of saturated fatty acids, while linseed oil promoted the opposite effect.
RESUMEN
The CATS (FAM64A) protein interacts with CALM (PICALM) and the leukemic fusion protein CALM/AF10. CATS is highly expressed in leukemia, lymphoma and tumor cell lines and its protein levels strongly correlates with cellular proliferation in both malignant and normal cells. In order to obtain further insight into CATS function we performed an extensive analysis of CATS expression during differentiation of leukemia cell lines. While CATS expression decreased during erythroid, megakaryocytic and monocytic differentiation, a markedly increase was observed in the ATRA induced granulocytic differentiation. Lentivirus mediated silencing of CATS in U937 cell line resulted in somewhat reduced proliferation, altered cell cycle progression and lower migratory ability in vitro; however was not sufficient to inhibit tumor growth in xenotransplant model. Of note, CATS knockdown resulted in reduced clonogenicity of CATS-silenced cells and reduced expression of the self-renewal gene, GLI-1. Moreover, retroviral mediated overexpression of the murine Cats in primary bone marrow cells lead to decreased colony formation. Although our in vitro data suggests that CATS play a role in cellular processes important for tumorigenesis, such as cell cycle control and clonogenicity, these effects were not observed in vivo.