Enhanced expression of ras gene products in psoriatic epidermis

Abstract

The ras oncogene product ras p21 is structurally homologous to guanine nucleotide-binding proteins and plays an important role in transducing signals elicited by membrane receptors into intracellular metabolism. We examined psoriatic tissues for expression of ras p21 and compared them with normal skin, using the indirect immunofluorescence technique with the anti-ras p21 monoclonal antibody (MoAb), rp-35. In normal epidermis of five healthy individuals and uninvolved epidermis of three psoriatic patients, only the basal layer was positively stained by rp-35. The spinous layer was negative or faintly positive. In contrast, all psoriatic epidermis obtained from 13 psoriatic patients had strong reactivity with rp-35 throughout the epidermis. There were no differences in the staining pattern of hair follicles, sebaceous glands, eccrine glands, and eccrine ducts, which positively reacted with rp-35, between psoriatic and normal skin. The functions of ras p21 have not been clearly identified in mammalian cells; however recent reports reveal that cyclic AMP production is inhibited by the transfection of activated ras gene into normal cells. Enhanced expression of ras p21 in psoriatic epidermis may be indicative of some mechanism of defective beta-adrenergic responsiveness, which is considered to be one of the important pathophysiological phenomena causing the hyperproliferative condition in psoriasis.

Neurofibromatosis type 1 tumour suppressor gene expression is deficient in psoriatic skin in vivo and in vitro: a potential link to increased Ras activity

“…Mutations that result in constitutive active Ras may lead to cellular transformation 25 . A recent report describes increased activation of Ras in psoriatic lesions, 26 and enhanced expression of Ras was reported earlier 27 …”

Place des oncogènes et des facteurs de croissance dans la physiopathologie du psoriasis

“…Des anomalies du système adény late cyclase, dont certains composants pourraient être rangés parmi des onco gènes potentiels, comme la sous-unité ex de la protéine GS, ont été rappor tés. Kobayashi a rapporté une distri bution anormale de la protéine p21'as dans la peau psoriasique où, contrai rement à son expression limitée à la couche basale de l'épiderme normal, elle est retrouvée exprimée sur toute la hauteur de l'épiderme psoriasique [19].…”