A study of the differentiation and dedifferentiation of three human melanoma cell lines

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dc.contributor.advisorKidson, Sueen_ZA
dc.contributor.authorDavids, Lester Merlinen_ZA
dc.date.accessioned2017-12-12T14:24:17Z
dc.date.available2017-12-12T14:24:17Z
dc.date.issued1997en_ZA
dc.description.abstractPigment formation in melanocytes is the end-point of a series of biochemical reactions involving numerous melanocyte-specific proteins including, inter alia, the enzymes tyrosinase, tyrosinase-related protein-1 (TRP-1 ), tyrosinase-related protein-2 (TRP-2) and the melanosomal protein encoded by the P gene. The function of tyrosinase and TRP-2 have recently been clarified, but the roles of TRP-1 and the P protein remain unknown. The first aim of this study was to examine the expression of these proteins at a transcriptional and translational level in order to provide more insight into possible mechanisms which may lead to changes in melanoma cell differentiation. Three human melanoma cell lines (Mel 1, Mel-2 and Mel-3) with varying levels of pigmentation (highly melanised to amelanotic) were examined by enzyme assays and RNA quantification methods. The results showed gene expression of all four genes in the highly melanised Mel-1 and amelanotic Mel-3 cell lines. TRP-1 and TRP-2 were not expressed in the melanised Mel-2 cell line. These results suggest that there is no correlation between tyrosinase gene expression and level of pigmentation in these cell lines. In addition, they show that the level of pigmentation of human melanoma cell does not necessarily correlate to the level or pattern expression of the tyrosinase gene family. Furthermore the results of the present study show that the P gene is expressed at high levels in all the melanoma cell lines, irrespective of their level of pigmentation . The second broad aim of this study was to determine the effect of melanocytestimulating hormone (a melanogenic stimulator) on melanogenesis in Mel-1 cells. Mel-1 cells, which were exposed to 10⁻⁷ M MSH for 6 days, showed no change in tyrosinase mRNA levels, but the mRNA levels of TRP-1, TRP-2 and the P gene were reduced. This suggested the presence of a possible co-ordinated down-regulatory mechanism in the Mel-1 cells under the influence of MSH.en_ZA
dc.identifier.apacitationDavids, L. M. (1997). <i>A study of the differentiation and dedifferentiation of three human melanoma cell lines</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Department of Human Biology. Retrieved from http://hdl.handle.net/11427/26582en_ZA
dc.identifier.chicagocitationDavids, Lester Merlin. <i>"A study of the differentiation and dedifferentiation of three human melanoma cell lines."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Department of Human Biology, 1997. http://hdl.handle.net/11427/26582en_ZA
dc.identifier.citationDavids, L. 1997. A study of the differentiation and dedifferentiation of three human melanoma cell lines. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Davids, Lester Merlin AB - Pigment formation in melanocytes is the end-point of a series of biochemical reactions involving numerous melanocyte-specific proteins including, inter alia, the enzymes tyrosinase, tyrosinase-related protein-1 (TRP-1 ), tyrosinase-related protein-2 (TRP-2) and the melanosomal protein encoded by the P gene. The function of tyrosinase and TRP-2 have recently been clarified, but the roles of TRP-1 and the P protein remain unknown. The first aim of this study was to examine the expression of these proteins at a transcriptional and translational level in order to provide more insight into possible mechanisms which may lead to changes in melanoma cell differentiation. Three human melanoma cell lines (Mel 1, Mel-2 and Mel-3) with varying levels of pigmentation (highly melanised to amelanotic) were examined by enzyme assays and RNA quantification methods. The results showed gene expression of all four genes in the highly melanised Mel-1 and amelanotic Mel-3 cell lines. TRP-1 and TRP-2 were not expressed in the melanised Mel-2 cell line. These results suggest that there is no correlation between tyrosinase gene expression and level of pigmentation in these cell lines. In addition, they show that the level of pigmentation of human melanoma cell does not necessarily correlate to the level or pattern expression of the tyrosinase gene family. Furthermore the results of the present study show that the P gene is expressed at high levels in all the melanoma cell lines, irrespective of their level of pigmentation . The second broad aim of this study was to determine the effect of melanocytestimulating hormone (a melanogenic stimulator) on melanogenesis in Mel-1 cells. Mel-1 cells, which were exposed to 10⁻⁷ M MSH for 6 days, showed no change in tyrosinase mRNA levels, but the mRNA levels of TRP-1, TRP-2 and the P gene were reduced. This suggested the presence of a possible co-ordinated down-regulatory mechanism in the Mel-1 cells under the influence of MSH. DA - 1997 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1997 T1 - A study of the differentiation and dedifferentiation of three human melanoma cell lines TI - A study of the differentiation and dedifferentiation of three human melanoma cell lines UR - http://hdl.handle.net/11427/26582 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/26582
dc.identifier.vancouvercitationDavids LM. A study of the differentiation and dedifferentiation of three human melanoma cell lines. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Department of Human Biology, 1997 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/26582en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Human Biologyen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherCell Biologyen_ZA
dc.titleA study of the differentiation and dedifferentiation of three human melanoma cell linesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc (Med)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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