Niveles séricos del factor de crecimiento semejante a la insulina tipo I como posible marcador de la evolución de pacientes con leucemia linfática crónica

ROXANA SCHILLACI, DAMASIA BECU-VILLALOBOS, ADRIANA GALEANO, SANDRA SAPIA Y RAIMUNDO F. BEZARES.

Hematologia

Lugar: Buenos Aires; Año: 2006 vol. 10 p. 13 - 19

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of long-lived B lymphocytes blocked in G0/1 by impaired apoptosis. Because insulin-like growth factor-I (IGF-I) is known for its antiapoptotic effects in different cell types, we investigated whether IGF-I and its receptor (IGF-IR) participate in autocrine/paracrine loops affecting survival of CLL cells. We demonstrated the presence of IGF-IR protein and mRNA in CLL cells in 44% and 59% of patients, respectively. IGF-IR expression in CLL patients was positively correlated with the expression of the antiapoptotic protein Bcl-2 and was involved in CLL cell survival in vitro. Serum IGF-I was elevated in CLL patients, but growth hormone was normal. CLL cells expressed IGF-I mRNA and secreted the growth factor in vitro. Therefore, local production of IGF-I can account for the increased levels of serum IGF-I, independently of growth hormone, and may be related to autocrine/paracrine control of lymphocyte survival acting at IGF-IR. This is the first demonstration of IGF-IR expression in a subgroup of CLL patients and of its antiapoptotic effects in vitro, highlighting the importance of this growth factor receptor as a possible therapeutic target in CLL.