An experimental study of human melanoma cells cutured in vitro
type: CreativeWork
description: This thesis records the results of a series of experiments that were designed to examine the biology of human malignant melanoma cells cultured in vitro. The studies were so planned as to document phenotypic differences that exist between melanomas, to define respects in which melanoma cell differentiation could be modulated and to correlate biochemical variability with in vivo behaviour as measured in the nude mouse. Melanoma cell lines were established from biopsy material obtained from 7 patients at Groote Schuur Hospital. Two of these lines synthesized tyrosinase and melanin at a rate that was directly related to cell density. The five remaining lines did not pigment. ii All of the lines showed aneuploidy; 5 of the 7 showed anchorageindependent growth; and 6 of the 7 grew as lethal tumours in nude mice. As has been found with all other melanomas studied, these cells released a plasminogen activator that was chemically and immunologically identical to tissue activator. One of the lines proved to be an exception to this general rule in that it synthesized urokinase-type enzyme. Unlike most other human cells cultured in vitro, melanoma cells proved to be relatively refractory to hormonal stimuli. Addition of estrogen, progesterone, testosterone, dexamethasone or melanocyte-stimulating hormone to the culture medium had very little effect on cellular release of plasminogen activator, upon cell growth, or upon cellular morphology. Although remarkably resistant to hormonal influences, cellular release of plasminogen activator did appear to be inhibited to a striking degree by cocultivation with normal skin fibroblasts. This observation led to the discovery of a phenomenon in which fibroblasts of many types bound tissue-type plasminogen activator and so removed it from the medium. This was accompanied by an apparent change in molecular weight of the melanoma cell enzyme from 72K daltons to approximately 115K daltons, suggesting the presence of a 40-SOK binding molecule.…
abstract: This thesis records the results of a series of experiments that were designed to examine the biology of human malignant melanoma cells cultured in vitro. The studies were so planned as to document phenotypic differences that exist between melanomas, to define respects in which melanoma cell differentiation could be modulated and to correlate biochemical variability with in vivo behaviour as measured in the nude mouse. Melanoma cell lines were established from biopsy material obtained from 7 patients at Groote Schuur Hospital. Two of these lines synthesized tyrosinase and melanin at a rate that was directly related to cell density. The five remaining lines did not pigment. ii All of the lines showed aneuploidy; 5 of the 7 showed anchorageindependent growth; and 6 of the 7 grew as lethal tumours in nude mice. As has been found with all other melanomas studied, these cells released a plasminogen activator that was chemically and immunologically identical to tissue activator. One of the lines proved to be an exception to this general rule in that it synthesized urokinase-type enzyme. Unlike most other human cells cultured in vitro, melanoma cells proved to be relatively refractory to hormonal stimuli. Addition of estrogen, progesterone, testosterone, dexamethasone or melanocyte-stimulating hormone to the culture medium had very little effect on cellular release of plasminogen activator, upon cell growth, or upon cellular morphology. Although remarkably resistant to hormonal influences, cellular release of plasminogen activator did appear to be inhibited to a striking degree by cocultivation with normal skin fibroblasts. This observation led to the discovery of a phenomenon in which fibroblasts of many types bound tissue-type plasminogen activator and so removed it from the medium. This was accompanied by an apparent change in molecular weight of the melanoma cell enzyme from 72K daltons to approximately 115K daltons, suggesting the presence of a 40-SOK binding molecule.…
author: Hoal, Eileen Garner
keywords: Medicine
date published: 1981
date modified: 2026-07-22T22:23:05Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Not Specified

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/36078