Publicação
The role of ceramide in acetate-induced apoptosis in colorectal carcinoma cell lines
| Resumo: | Colorectal carcinoma (CRC) is the third most common malignant neoplasia worldwide and one of the leading causes of cancer death in Europe. In this context the finding of new therapeutic approaches is of prime importance to fight these types of cancers. Ceramide is an evolutionarily conserved second messenger capable of regulating vital cellular functions including cell growth, differentiation, senescence and apoptosis among others. Due to the importance of this molecule a lot of research has been done, in the past few years, to elucidate how the levels of ceramide can be modulated in cancer cells in order to overcome chemoresistance and induce apoptosis. The Propionibacteria from specific dairy products are able of surviving in human intestine producing short chain fatty acids (SCFA), particularly acetate and propionate. Acetate is able to induce apoptosis in CRC cells and more recently it was reported by our laboratory that upon acetate treatment, LMP and release of cathepsin D occurred in CRC cells undergoing apoptosis. It was also shown that ceramide can activate and release cathepsin D into the cytoplasm. However the involvement of ceramide in the apoptosis induced by acetate in CRC to the best of our knowledge was never investigated. The present study aimed to address the possible involvement of ceramide generation in acetate-induced cell death in CRC cell lines (RKO and HCT-15). We study cell viability and apoptosis in cells treated with C2-ceramide as well as the cell viability of cells co-treated with acetate and ceramide synthesis inhibitors: Desipramine (a sphingomyelinase pathway inhibitor) or Myriocin (a ceramide de novo synthesis pathway inhibitor). Our results confirm that C2-ceramide induces cell death by apoptosis in CRC cell lines. Upon treatment of both cell lines with ceramide inhibitors we observed that RKO cells were more sensitive to Desipramine at high concentrations than HCT-15 cells. Co-treatment with Myriocin or Desipramine and acetate failed to reduce the cytotoxicity of acetate, suggesting that neither the sphingomyelinase synthesis pathway, by the action of acid SMase, nor the ceramide de novo synthesis pathway is involved in acetate-induced apoptosis in CRC cells. In summary, the results confirm that ceramide induce apoptosis in HCT-15 and RKO cell lines but further studies, using all the inhibitors of the ceramide generation pathways, are needed to better clarify the involvement of ceramide in acetate-induced apoptosis in CRC cells. |
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| Autores principais: | Silva, Martha Amaro da |
| Ano: | 2012 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Colorectal carcinoma (CRC) is the third most common malignant neoplasia worldwide and one of the leading causes of cancer death in Europe. In this context the finding of new therapeutic approaches is of prime importance to fight these types of cancers. Ceramide is an evolutionarily conserved second messenger capable of regulating vital cellular functions including cell growth, differentiation, senescence and apoptosis among others. Due to the importance of this molecule a lot of research has been done, in the past few years, to elucidate how the levels of ceramide can be modulated in cancer cells in order to overcome chemoresistance and induce apoptosis. The Propionibacteria from specific dairy products are able of surviving in human intestine producing short chain fatty acids (SCFA), particularly acetate and propionate. Acetate is able to induce apoptosis in CRC cells and more recently it was reported by our laboratory that upon acetate treatment, LMP and release of cathepsin D occurred in CRC cells undergoing apoptosis. It was also shown that ceramide can activate and release cathepsin D into the cytoplasm. However the involvement of ceramide in the apoptosis induced by acetate in CRC to the best of our knowledge was never investigated. The present study aimed to address the possible involvement of ceramide generation in acetate-induced cell death in CRC cell lines (RKO and HCT-15). We study cell viability and apoptosis in cells treated with C2-ceramide as well as the cell viability of cells co-treated with acetate and ceramide synthesis inhibitors: Desipramine (a sphingomyelinase pathway inhibitor) or Myriocin (a ceramide de novo synthesis pathway inhibitor). Our results confirm that C2-ceramide induces cell death by apoptosis in CRC cell lines. Upon treatment of both cell lines with ceramide inhibitors we observed that RKO cells were more sensitive to Desipramine at high concentrations than HCT-15 cells. Co-treatment with Myriocin or Desipramine and acetate failed to reduce the cytotoxicity of acetate, suggesting that neither the sphingomyelinase synthesis pathway, by the action of acid SMase, nor the ceramide de novo synthesis pathway is involved in acetate-induced apoptosis in CRC cells. In summary, the results confirm that ceramide induce apoptosis in HCT-15 and RKO cell lines but further studies, using all the inhibitors of the ceramide generation pathways, are needed to better clarify the involvement of ceramide in acetate-induced apoptosis in CRC cells. |
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