Background. Tuberous sclerosis complex (TSC), a tumor syndrome caused by mutations in TSC1 or TSC2 genes, is characterized by the development of hamartomas. We previously isolated, from an angiomyolipoma of a TSC2 patient, a homogenous population of smooth muscle-like cells (TSC2-/- ASM cells) that have a mutation in the TSC2 gene as well as TSC2 loss of heterozygosity (LOH) and consequently, do not produce the TSC2 gene product, tuberin. TSC2-/- ASM cell proliferation is EGF-dependent. Methods and Findings. Effects of EGF on proliferation of TSC2-/- ASM cells and TSC2-/- ASM cells transfected with TSC2 gene were determined. In contrast to TSC2-/- ASM cells, growth of TSC2-transfected cells was not dependent on EGF. Moreover, phosphorylation of Akt, PTEN, Erk and S6 was significantly decreased. EGF is a proliferative factor of TSC2-/- ASM cells. Exposure of TSC2-/- ASM cells to anti-EGFR antibodies significantly inhibited their proliferation, reverted reactivity to HMB45 antibody, a marker of TSC2-/- cell phenotype, and inhibited constitutive phosphorylation of S6 and ERK. Exposure of TSC2-/- ASM cells to rapamycin reduced the proliferation rate, but only when added at plating time. Although rapamycin efficiently inhibited S6 phosphorylation, it was less efficient than anti-EGFR antibody in reverting HMB45 reactivity and blocking ERK phosphorylation. In TSC2-/- ASM cells specific PI3K inhibitors (e.g. LY294002, wortmannin) and Akt1 siRNA had little effect on S6 and ERK phosphorylation. Following TSC2-gene transfection, Akt inhibitor sensitivity was observed. Conclusion. Our results show that an EGF independent pathway is more important than that involving IGF-I for growth and survival of TSC-/- ASM cells, and such EGF-dependency is the result of the lack of tuberin.
Anti-EGFR Antibody Efficiently and Specifically Inhibits Human TSC2-/- Smooth Muscle Cell Proliferation. Possible Treatment Options for TSC and LAM / E. Lesma, V. Grande, S. Ancona, S. Carelli, A.M. Di Giulio, A. Gorio. - In: PLOS ONE. - ISSN 1932-6203. - 3:10(2008), p. e3558.e3558.
|Titolo:||Anti-EGFR Antibody Efficiently and Specifically Inhibits Human TSC2-/- Smooth Muscle Cell Proliferation. Possible Treatment Options for TSC and LAM|
LESMA, ELENA ANNA (Primo)
GRANDE, VERA (Secondo)
DI GIULIO, ANNA MARIA (Penultimo)
GORIO, ALFREDO (Ultimo)
|Parole Chiave:||TSC ; phosphorylation of S6 and Erk ; anti-EGFR antibody ; rapamycin|
|Settore Scientifico Disciplinare:||Settore BIO/14 - Farmacologia|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1371/journal.pone.0003558|
|Appare nelle tipologie:||01 - Articolo su periodico|