RESUMO
Homozygous deletions in the region of chromosome 9p21 are frequent in human melanoma. Mutations in the p16INK4A cyclin-dependent kinase inhibitor (CDI) gene at this locus have implicated the product of this gene as a tumor suppressor. Less attention has been focused on the homologous, closely linked p15INK4B gene. To facilitate study of the phenotypic effects of restoring expression of the latter in aggressive melanoma cells lacking INK4 expression, we inserted the cDNA encoding p15INK4B into an autonomously maintained plasmid under positive tetracycline control ('TET ON' system). Similarly regulated luciferase and herpes thymidine kinase sequences were used as controls. We demonstrate that this system enabled efficient, and reasonably uniform, induction of p15INK4B expression in a human melanoma cell line exposed to the tetracycline derivative, doxycycline. Flow cytometry showed that this induction resulted in substantial accumulation of cells in the G0/G1 phase of the cell cycle. This system will facilitate detailed analysis of the cell cycle inhibitory mechanisms of this CDI in human melanoma cells.
Assuntos
Proteínas de Transporte/genética , Proteínas de Ciclo Celular , Tetraciclina/farmacologia , Proteínas Supressoras de Tumor , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Inibidor de Quinase Dependente de Ciclina p15 , Inibidor p16 de Quinase Dependente de Ciclina , Doxiciclina/farmacologia , Citometria de Fluxo , Regulação da Expressão Gênica/efeitos dos fármacos , Herpesvirus Humano 4/genética , Humanos , Luciferases/genética , Melanoma , Mutação , Plasmídeos/genética , Proteínas Recombinantes de Fusão/efeitos dos fármacos , Proteínas Recombinantes de Fusão/genética , Proteína do Retinoblastoma/genética , Simplexvirus/enzimologia , Timidina Quinase/genética , Transativadores/genética , Transfecção , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismoRESUMO
More than 100 years has passed since the first report of a nevus comedonicus. The earliest reports emphasized the inflammatory aspect of the nevus comedonicus as being the most significant problem. In the past 30 years, publications have ignored the inflammatory aspect of nevus comedonicus while emphasizing a variety of associated malformations. In this review, we describe five prepubertal children with prominent and persistent inflammatory changes limited to areas within a nevus comedonicus. In our experience, inflammation can be severe and resistant to treatment. Ultimately, surgical removal of the involved skin was required in two children.