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| Author(s): |
Ronaldo Rodrigues Ribeiro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI) |
| Defense date: | 2023-12-11 |
| Examining board members: |
Joao Gustavo Pessini Amarante Mendes;
Enrique Mario Boccardo Pierulivo;
Eduardo Moraes Rego Reis;
Bryan Eric Strauss
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| Advisor: | Joao Gustavo Pessini Amarante Mendes |
| Abstract | |
Melanoma is the most lethal skin cancer. It can be divided into four groups depending on the mutation type. Ras, a protein associated with different biochemical processes, such as proliferation, differentiation, morphology, and apoptosis, is mutated in 28% of patients. Ras has already been shown to act in the NF-B pathway and modulate production of cytokines. The main effectors of Ras regarding cell death are members of the RASSF (Ras-Association Domain Family), which is composed of ten members (RASSF1-10) that share a RA domain (Ralgds/AF6). Depending on the location of the RA domain, the members are divided into two groups, the C-terminal group (RASSF1-6) and the N-terminal (RASSF7-10). RASSF9 was initially described as P-CIP1 and was later considered to be a member of the RASSF family due to its similarity to RASSF7 and RASSF8. RASSF9 protein acts as a tumor suppressor in breast and gastric cancers, by promoting the G1/S transition and inducing apoptosis. In contrast, RASSF9 induces growth of esophageal squamous tumors. Our current project has two main focuses, the first was to investigate the role of RASSF9 in the context of melanoma. We developed two murine melanoma cell lines (Tm1.Luc and Tm5) deficient for RASSF9 using the CRISPR/Cas9 system. We observed a duality between the two cell lines in the context of resistance to induced cell death and migration and invasion capacities. On the one hand, upon cisplatin treatment Tm1.Luc.R9KO cells seem to be sensitize to cell death. On the other, Tm5.R9KO cells displayed either no difference or a slight reduction in the percentage of dead cells in different treatments. The second aim was to investigate the oncogenic stress-induced production of cytokines. We induced the expression of oncogenic HRasV12 and BRaf and observed that this clearly induced the production of IL-6 and IL-8. Nrf2 also seems to induce cytokine production, but this effect is probably not related to the Ras pathway once Keap1 overexpression was insufficient to inhibit cytokine production. In conclusion, RASSF9 appears to participate in the process of migration, invasion, and resistance to cell death. Moreover, oncogenic Ras and Nrf2 induce cytokine production, but this process is probably not dependent on each other. Additional experiments are necessary to confirm our findings. (AU) | |
| FAPESP's process: | 20/03304-4 - Analysis of RASSF9 function in melanoma in 2D and 3D models |
| Grantee: | Ronaldo Rodrigues Ribeiro |
| Support Opportunities: | Scholarships in Brazil - Master |