Effect of human epidermal growth factor on the tumor cell line A431: in vivo analysis of tumor growth inhibition and gene expression
Abstract
The historical tag of the epidermal growth factor (EGF) as carcinogenesis promoter has not been uniformly reproduced, since, in some experiments, malignant cells are bound to growth inhibition and apoptosis. The present study intends to obtain additional data on the interaction of EGF with cancer cells by analyzing its effect in vitro on the growth of cultured A431 cells, and in vivo on nude mice xenotransplanted with this cell line; identifying, in addition, the gene expression patterns for a selected group of genes related to EGF and cancer pathways in the solid tumor. EGF-treated animals showed significantly smaller tumor volumes than controls, suggesting cellular growth inhibition mediated by this factor. Similar results were obtained regarding the proliferation of cultured A431 when treated with 2.2, 33 and 165 nM of EGF. These results may imply a common mechanism for the EGF-mediated growth inhibition of A431 cells in both biological conditions (in vivo and in vitro). The action of EGF at nanomolar concentrations may trigger a transient recovery of the tumor suppressor ability of tumor cells through the reduction of the biological action of mutated TP53, cell cycle arrest due to a decrease in Cdk4 expression levels and the initiation of caspase through the activation of CASP9.
