Evaluation of chemotherapeutic potential of natural extracts using 3D models of...

• Author(s): Silva, Inês Alexandra Marreiros
• Date: 2013
• Persistent ID: http://hdl.handle.net/10362/10982
• Origin: Repositório Institucional da UNL
• Subject(s): 3D cell models; Colon cancer; Natural extracts; Phytochemicals; Chemotherapy
• Document Type: Master Thesis
• Language: English
• Advisor(s): Serra, Ana; Brito, Catarina

Description

Dissertation to obtain master degree in Biotechnology Recently there is a growing interest in cancer treatment through the use of natural compounds. In particular, phenolic compounds and monoterpenes found in fruits and vegetables are very attractive in the prevention and chemotherapy of various types of cancer. However, many promising compounds previously tested in in vitro cell models fail to demonstrate activity when evaluated in vivo. Therefore, there is an emerging need to develop more robust and reliable cellular models for pre-clinical evaluation of new chemotherapeutic agents. The main goal of this thesis was the evaluation of the chemotherapeutic potential of natural extracts, rich in bioactive compounds, using 3D models of colon cancer. For this purpose, a 3D model of human colorectal cancer cell line HT29 was developed. By culturing HT29 cells in a stirred culture system, it was possible to obtain 3D cellular spheroids with different size diameter during culture time. It was verified phenotypic changes within the spheroid along culture, such as formation of apoptotic core and altered expression of stem and epithelial markers in different spheroid areas, which are typical features of tumor progression. After an initial screening of the antiproliferative potential of 14 natural extracts performed in a 2D model of HT29 cells, the most promising samples were selected for further analysis in the 3D model. Cherry and orange extracts showed potential anticancer effect in HT29 aggregates through the inhibition of cell proliferation, induction of apoptosis and cell cycle arrest. A decrease on the bioactive effect was verified with the increase of aggregate diameter, probably due to limited diffusion. The anticancer activity was correlated with the phytochemical composition of natural extracts. For cherry extract, perillyl alcohol was the main bioactive compound identified whereas for orange extract, compounds like nobiletin, tangeretin and sinensetin were highlighted. Results of this thesis demonstrated that natural extracts of cherry and orange contain bioactive molecules with promising application on the development of new therapies for colon cancer treatment. The use of 3D cell models is a valuable tool for the study and evaluation of the effect of new chemotherapeutic compounds.