Publicação
Discovering New Molecules for Diagnosis and Non-Toxic Differentiation Therapy in Colorectal Cancer
| Resumo: | Colorectal cancer (CRC) is the third most prevalent type of cancer worldwide. Therefore, better diagnostic tools and anticancer therapies have been some of the most sought out topics in CRC research. MicroRNAs (miRNAs), a type of short non-coding single strand RNA molecules capable of repressing mRNA translation, are rising as potential and powerful diagnostic and prognostic biomarkers in cancer. In CRC, differences in the expression pattern of certain miRNAs in tissue have been already described, suggesting that miRNAs could represent an effective diagnostic option for this particular disease. On the other hand, cancer stem cells (CSCs), a subpopulation of cells within tumors with phenotypic resemblance to normal stem cells, have been implicated in tumorigenesis, metastization and recurrence processes. Indeed, these undifferentiated cells are not entirely eliminated with the classical anti-proliferative approaches, being responsible for tumorigenic potential and rapid relapse. Thus, efficient therapies targeting this specific type of cancer cells are being developed, with special emphasis on combinatorial drug therapies, to sensitize cells to conventional anticancer treatments and therefore reduce the toxicity associated with high doses of chemotherapeutic treatments. Two major objectives were pursued in this project: 1) to optimize methodologies to assess the diagnostic and prognostic potential of a panel of miRNAs in patients with CRC, prior to and after being submitted to chemoradiotherapy; and 2) to evaluate the effectiveness of two chemical compounds, from an in-house library, as potential non-toxic differentiation drivers in CRC cells and characterize their specific signaling pathways. The qPCR analysis of human colonic samples revealed differential expression profiles for several miRNAs derived from normal and tumor tissues, as well as before and after chemoradiotherapy. Nevertheless, these data are still preliminary and further studies are necessary to validate the prognostic and diagnostic value of these miRNAs. In addition, we identified the biological effects of two potential candidate molecules, a spiropyrazoline oxindole (DS6) and a 3-piperidinyl-indole (SAS9), capable of promoting differentiation in human colorectal carcinoma cells. Although both compounds had impact on CRC cells, DS6 was particularly successful, being capable of reducing the levels of stemness and pluripotency markers, increasing differentiation, inhibiting self-renewal and exhibiting a slight synergistic effect in sensitizing cells to a classical chemotherapeutic, 5-fluorouracil. Page | III Interestingly, by using isogenic p53+/+ and p53-/- HCT116 cell lines, we were able to observe a tendency for DS6 to develop its differentiation effect only in p53+/+ cells, suggesting a p53-dependent mechanism of action for this molecule. Further studies are still required to validate the DS6 mechanism of action, as well as consolidate the data on its therapeutic potential for differentiation in CRC. Altogether, our results shed light on two aspects of CRC research, related with diagnosis and treatment- We open the way to optimize the discovery of novel miRNAs as biomarkers for diagnosis and prognosis and contribute to uncover new regulators of differentiation in CRC. |
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| Autores principais: | Paiva, Nuno André Silva |
| Assunto: | Biomarkers Cancer stem cells Colorectal cancer Differentiation therapy microRNAs Teses de mestrado - 2018 |
| Ano: | 2018 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Colorectal cancer (CRC) is the third most prevalent type of cancer worldwide. Therefore, better diagnostic tools and anticancer therapies have been some of the most sought out topics in CRC research. MicroRNAs (miRNAs), a type of short non-coding single strand RNA molecules capable of repressing mRNA translation, are rising as potential and powerful diagnostic and prognostic biomarkers in cancer. In CRC, differences in the expression pattern of certain miRNAs in tissue have been already described, suggesting that miRNAs could represent an effective diagnostic option for this particular disease. On the other hand, cancer stem cells (CSCs), a subpopulation of cells within tumors with phenotypic resemblance to normal stem cells, have been implicated in tumorigenesis, metastization and recurrence processes. Indeed, these undifferentiated cells are not entirely eliminated with the classical anti-proliferative approaches, being responsible for tumorigenic potential and rapid relapse. Thus, efficient therapies targeting this specific type of cancer cells are being developed, with special emphasis on combinatorial drug therapies, to sensitize cells to conventional anticancer treatments and therefore reduce the toxicity associated with high doses of chemotherapeutic treatments. Two major objectives were pursued in this project: 1) to optimize methodologies to assess the diagnostic and prognostic potential of a panel of miRNAs in patients with CRC, prior to and after being submitted to chemoradiotherapy; and 2) to evaluate the effectiveness of two chemical compounds, from an in-house library, as potential non-toxic differentiation drivers in CRC cells and characterize their specific signaling pathways. The qPCR analysis of human colonic samples revealed differential expression profiles for several miRNAs derived from normal and tumor tissues, as well as before and after chemoradiotherapy. Nevertheless, these data are still preliminary and further studies are necessary to validate the prognostic and diagnostic value of these miRNAs. In addition, we identified the biological effects of two potential candidate molecules, a spiropyrazoline oxindole (DS6) and a 3-piperidinyl-indole (SAS9), capable of promoting differentiation in human colorectal carcinoma cells. Although both compounds had impact on CRC cells, DS6 was particularly successful, being capable of reducing the levels of stemness and pluripotency markers, increasing differentiation, inhibiting self-renewal and exhibiting a slight synergistic effect in sensitizing cells to a classical chemotherapeutic, 5-fluorouracil. Page | III Interestingly, by using isogenic p53+/+ and p53-/- HCT116 cell lines, we were able to observe a tendency for DS6 to develop its differentiation effect only in p53+/+ cells, suggesting a p53-dependent mechanism of action for this molecule. Further studies are still required to validate the DS6 mechanism of action, as well as consolidate the data on its therapeutic potential for differentiation in CRC. Altogether, our results shed light on two aspects of CRC research, related with diagnosis and treatment- We open the way to optimize the discovery of novel miRNAs as biomarkers for diagnosis and prognosis and contribute to uncover new regulators of differentiation in CRC. |
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