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Doctoral Thesis
DOI
10.11606/T.23.2009.tde-19122009-121750
Document
Author
Full name
Thaís Acquafreda Antunes
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2009
Supervisor
Committee
Nunes, Fabio Daumas (President)
Graner, Edgard
Loyola, Adriano Motta
Okamoto, Oswaldo Keith
Tucci, Renata
Title in Portuguese
Perfil da expressão de genes homeobox em linhagens celulares de carcinoma epidermóide de boca estimuladas pelo ácido retinóico
Keywords in Portuguese
Carcinoma de Células Escamosas
Genes Homeobox
Retinóides
Abstract in Portuguese
O carcinoma epidermóide de boca, neoplasia maligna de boca mais comum, pode originar-se de lesões potencialmente malignas. O ácido retinóico, que atua no crescimento e diferenciação celular, tem sido comumente estudado como um possível quimioterápico na prevenção dessa progressão. Embora o mecanismo pelo qual o ácido retinóico previne essa progressão, e promove a parada do crescimento celular, não esteja estabelecido, sabe-se que os genes homeobox são importantes alvos do ácido retinóico durante o desenvolvimento embrionário e diferenciação tecidual. Este estudo visa determinar se a modulação da expressão desses genes está envolvida na inibição do crescimento pelo ácido retinóico em carcinoma epidermóide de boca. Para isso, foi realizado PCR array para avaliar a expressão de 84 genes homeobox na linhagem celular de carcinoma epidermóide de boca sensível ao ácido retinóico SSC-25, comparando com a linhagem resistente, SSC-9, após o tratamento com ácido retinóico por sete dias. Os resultados mostraram nove genes com perda de expressão e quatro com alta expressão. A validação por qPCR de 7 desses genes confirmou os resultados. Desses, três genes(ALX1, DLX3, TLX1) foram selecionados para terem a expressão avaliada em amostras tratadas por 3, 5 e 7 dias. O gene ALX1 apresentou baixa expressão apenas no dia 7. O gene DLX3 apresentou baixa expressão no terceiro dia com maior decréscimo no sétimo. Já o gene TLX1, mostrou baixa significativa no quinto dia, com valores semelhantes no sétimo. Os dados mostram genes homebox são modulados pelo ácido retinóico em linhagens de carcinoma epidermóide de boca. No entanto, esses genes não parecem ser alvo direto da inibição do crescimento promovida pelo ácido retinóico.
Title in English
Expression of homeobox gene in oral squamous cell carcinoma cell lines under retinoic acid stimulus
Keywords in English
Homebox genes
Retinoids
Squamous cell carcinoma
Abstract in English
Oral squamous cell carcinoma, the most frequent oral cancer, may arise from potentially malignant oral lesions. Retinoic acid, which plays a role in cell growth and differentiation, has been frequently studied as a possible chemotherapeutic agent in the prevention of this progression. While the mechanism by which retinoic acid prevents progression and suppresses cell growth has not been completely elucidated, it is known that homeobox genes represent important targets of retinoic acid during embryogenesis and differentiation. The present study aims to determine if modulation of the expression of these genes is involved in inhibition of OSCC cell growth by retinoic acid. In order to achieve this goal a PCR array was performed to evaluate the expression of 84 homeobox genes in retinoic acid sensitive SCC-25 cells compared to retinoic acid resistant SCC-9 cells following treatment with retinoic acid for 7 days. Results showed that 9 homeobox genes are downregulated and 4 are upregulated by retinoic acid. The validation confirmed these results. Three genes (ALX1, DLX3, TLX1) were selected for having their expression evaluated on samples treated with retinoic acid for 3, 5 and 7 days. Three different patterns of gene expression were observed. Gene ALX1 showed down-regulation only on day 7. Homeobox gene DLX3 showed reduced expression on day 3 and decreased expression on day 7. TLX1 showed a substantial down-regulation on day 5 with similar values on. The data presented show that a number of homeobox genes are modulated by retinoic acid in oral squamous cell carcinoma cell lines. However, these genes do not appear to be direct targets of growth suppression trigged by retinoic acid.
 
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Publishing Date
2010-01-28
 
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