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Publication
O potencial papel da TRIB2 no tratamento do melanoma com Tiazolidinedionas
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Advisor(s)
Abstract(s)
Embora o melanoma represente apenas 1% de todos os cancros de pele, este é
o que apresenta a maior taxa de mortalidade. Uma das principais causas do insucesso
terapêutico é a resistência às terapias anticancerígenas, onde a proteína TRIB2 tem
vindo a apresentar um papel de destaque, sendo associada ao aumento da resistência.
Os fármacos Rosiglitazona e Pioglitazona, agonistas do PPARγ, da família dos
antidiabéticos orais tiazolidinedionas (TZDs), já foram relatados anteriormente como
eficaz terapia para o melanoma – no entanto, existem resultados em que se verifica o
contrário. Um estudo preliminar, não publicado, verificou que a expressão de TRIB2
encontra-se diminuída em culturas de adipócitos tratados com Rosiglitazona.
Neste sentido, colocou-se as seguintes hipóteses: 1) As TZDs poderão levar a uma
diminuição dos níveis de TRIB2 nas células de melanoma; 2) A potencial redução dos
níveis de TRIB2 poderá estar envolvida no mecanismo de ação anticancerígena das TZDs.
Para validar experimentalmente as hipóteses desenvolvidas, tratou-se células de
melanoma UACC-62 com Rosiglitazona ou Pioglitazona (em diferentes concentrações e
com diferentes tempos de tratamento) e realizou-se a extração de proteínas para avaliar
os níveis de expressão de TRIB2 por Western blot, e ainda avaliou-se a
proliferação/viabilidade das células UACC-62 parentais e TRIB2-KO (dois clones de
células CRISPR independentes) tratadas com Rosiglitazona ou Pioglitazona através de
ensaios MTT.
Através da análise Western blot verificou-se que os tratamentos com as TZDs em
estudo aumentam a expressão de TRIB2 e de P-AKT nas células de melanoma. Os ensaios
MTT não revelaram nenhuma relação consistente entre os tratamentos standard com
fármaco e a viabilidade celular; já os tratamentos duplos (72h+24h) parecem causar um
aumento da viabilidade das células de melanoma.
Although melanoma represents only 1% of all skin cancers, it is the one that has the highest mortality rate. One of the main causes of therapeutic failure is the resistance to anticancer therapies, where the TRIB2 protein has been playing a prominent role, being associated with increased resistance. Rosiglitazone and Pioglitazone, PPARγ agonists, from the thiazolidinediones (TZDs) family of oral antidiabetics, have previously been reported as effective therapy for melanoma – however, there are results where the opposite is verified. A preliminary unpublished study found that TRIB2 expression is decreased in cultures of adipocytes treated with Rosiglitazone. In this sense, the following hypotheses were put forward: 1) TZDs could lead to a decrease in TRIB2 levels in melanoma cells; 2) The potential reduction in TRIB2 levels may be involved in the anticancer mechanism of action of TZDs. To experimentally validate the developed hypotheses, UACC-62 melanoma cells were treated with Rosiglitazone or Pioglitazone (at different concentrations and with different treatment times) and protein extraction was performed to assess TRIB2 expression levels by Western blot, and the proliferation/viability of parental UACC-62 and TRIB2-KO cells (two independent CRISPR cell clones) treated with Rosiglitazone or Pioglitazone was evaluated by MTT assays. Through Western blot analysis it was found that the treatments with the TZDs under study increase the expression of TRIB2 and P-AKT in melanoma cells. MTT assays revealed no consistent relationship between standard drug treatments and cell viability; on the other hand, double treatments (72h+24h) seem to cause an increase in the viability of melanoma cells.
Although melanoma represents only 1% of all skin cancers, it is the one that has the highest mortality rate. One of the main causes of therapeutic failure is the resistance to anticancer therapies, where the TRIB2 protein has been playing a prominent role, being associated with increased resistance. Rosiglitazone and Pioglitazone, PPARγ agonists, from the thiazolidinediones (TZDs) family of oral antidiabetics, have previously been reported as effective therapy for melanoma – however, there are results where the opposite is verified. A preliminary unpublished study found that TRIB2 expression is decreased in cultures of adipocytes treated with Rosiglitazone. In this sense, the following hypotheses were put forward: 1) TZDs could lead to a decrease in TRIB2 levels in melanoma cells; 2) The potential reduction in TRIB2 levels may be involved in the anticancer mechanism of action of TZDs. To experimentally validate the developed hypotheses, UACC-62 melanoma cells were treated with Rosiglitazone or Pioglitazone (at different concentrations and with different treatment times) and protein extraction was performed to assess TRIB2 expression levels by Western blot, and the proliferation/viability of parental UACC-62 and TRIB2-KO cells (two independent CRISPR cell clones) treated with Rosiglitazone or Pioglitazone was evaluated by MTT assays. Through Western blot analysis it was found that the treatments with the TZDs under study increase the expression of TRIB2 and P-AKT in melanoma cells. MTT assays revealed no consistent relationship between standard drug treatments and cell viability; on the other hand, double treatments (72h+24h) seem to cause an increase in the viability of melanoma cells.
Description
Keywords
Melanoma Pioglitazona PPARy Rosiglitazona Tiazolidinedionas TRIB2