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| Author(s): |
Rose Mara Ortega
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2014-02-28 |
| Examining board members: |
Karina Gottardello Zecchin;
Ana Carolina Fragoso Motta;
Lays Martin Sobral;
Roger Chammas;
Silvia Vanessa Lourenço
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| Advisor: | Edgard Graner; Karina Gottardello Zecchin |
| Abstract | |
Fatty acid synthase (FASN) is the metabolic enzyme responsible for the endogenous synthesis of the saturated long-chain fatty acid palmitate, from the precursors acetyl-CoA and malonyl-CoA. In contrast to most normal cells, the overexpression of FASN in several human malignancies, such as those of prostate, breast, ovary, melanoma, and soft tissue sarcomas has been associated with poor prognosis. FASN inhibition reduces cell proliferation by blocking DNA replication during S-phase, and induces apoptosis in several malignant neoplasias. We have previously shown that the specific inhibition of FASN activity significantly reduce proliferation and promote apoptosis, as demonstrated by the cytochrome c release and caspase-9 and -3 activation, as well as induces signi?cant changes in the free fatty acids composition of B16-F10 cells mitochondria. Here we investigated the events involved in cell cycle arrest subsequent to FASN inhibition with C75. C75 treatment significantly reduced melanoma cells proliferation and induced apoptosis in vitro and in mice. Cell cycle arrest after C75 treatment was evidenced by a significant increase in G0/G1 phase, as well as decline of the S phase, in comparison with untreated cells. Western blotting analysis showed significant accumulations of the tumor suppressor proteins p21WAF1/Cip1 and p27Kip1, together with decreased amounts of Skp2, essential for the proteasomal degradation of p27Kip1, and cdk2, a Ser/Thr protein kinase necessary for the G1/S transition, in C75-treated cells or mice tumors. The levels of other proteins involved in G1/S cell cycle progression, such as cyclin E, cdk4, and cdk6 were not affected by FASN inhibition. These results were confirmed by inhibition of FASN activity after C75 treatment and by RNAi for FASN. Antitumoral effect of C75 was suggested by reduced subcutaneous tumors volume when compared to controls mice. Our results suggest that melanoma murine B16-F10 cells proliferation is dependent on FASN activity, and its inhibition first modify the levels of some proteins involved in the transition G1?S of cell cycle, to finally induce apoptosis in neoplasic cells (AU) | |