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| Author(s): |
Juan Luiz Coelho da Silva
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2021-03-17 |
| Examining board members: |
Fabíola Traina;
Leticia Veras Costa Lotufo;
Erich Vinicius de Paula;
Rodrigo do Tocantins Calado de Saloma Rodrigues
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| Advisor: | Fabíola Traina; João Agostinho Machado Neto |
| Abstract | |
The implementation of new therapeutic strategies is dependent on the elucidation of non-explicit mechanisms and the identification of clinical and biological factors that distinguish patients for risk-adjusted therapies. Despite the growing interest in implementing target therapies, drug repositioning has gained notoriety as a strategy to shorten the time and costs involved in implementing new therapies. Through multi-experimental investigation, we aimed to identify new clinical predictors and provide preclinical evidence of new therapeutic opportunities in myeloid neoplasms. Using a knockin murine model with a conditioned expression of Jak2V617F expression, we investigated the effects of treatment with metformin on the hematopoietic stem cell (HSC) of myeloproliferative neoplasm (MPN). Treatment with metformin reduced splenomegaly, frequency of early erythroid progenitors in the spleen, platelet count in peripheral blood, and the clonogenic capacity of bone marrow mononuclear cells. Seventy-seven genes were differentially expressed between Kit-enriched cells from metformin-treated animals in comparison to those treated with vehicle, of which 30 were downregulated and 47 upregulated. In summary, treatment with metformin reduced splenomegaly in a murine model of MPN, but it does not emerge as a curative therapeutic strategy as it does not affect the MPN progenitors\' frequency. Through a transcriptomic strategy, we have developed a prognostic index for patients with myelodysplastic syndrome (MDS) based on the expression of genes involved in the processes of glycolysis, oxidative phosphorylation, and the tricarboxylic acids cycle, hereafter called cellular energetics processes. The molecular index (MBS) was able to stratify patients into three different risk groups. The adverse risk was independently associated with inferior overall survival. The score based on cellular energetics was also able to molecularly distinguish patients using gene-set enrichment analysis, in which the increased risk was associated with cell cycle progression, proliferation, and undifferentiation of HSC. MBS emerges as a molecular risk score for patients with MDS and indicates potential targets for therapeutic intervention. The signaling pathway of insulin-like growth factor 1 receptor (IGF1R) and insulin receptor substrates 1 and 2 (IRS1/2) has an important role in the development of several neoplasms but were underexplored in acute myeloid leukemia (AML). The expression of IGF1R, IGF2R, IRS1, and IRS2 was determined in the AML cohorts of the cancer genome atlas (n=173) and the international consortium of acute promyelocytic leukemia (n=105). The high expression of IGF1R and the expression ratio of IGF1R/IGF2R identified patients with unfavorable prognosis for AML and APL. The decreased expression of IRS1 has been associated with an unfavorable prognosis in patients with AML. AML cell lines NB4, NB4-R2, Kasumi-1, THP1, Molm13, and MV4; 11 were treated with IGF1R-IRS1/2 inhibitors linsitinib and NT157 and subjected to cytotoxicity and functional assays. Collectively, linsitinib acted as a cytostatic inhibitor and induced autophagy as a limiting mechanism of its efficiency, surpassed by the combination with the chloroquine autophagy inhibitor. NT157 was a cytotoxic agent in all cell lines, reduced cell proliferation, induced apoptosis, production of reactive oxygen species, and depolarization of the mitochondrial membrane. Molecularly, both compounds inhibited the IGF1R-IRS1/ 2, PI3K/AKT/mTOR, MAPK pathways, induced DNA damage, and caspase cleavage 3. Activation of the MAPK pathway of cell stress was activated only in response to therapy with NT157, suggesting that it is a non-explicit mechanism specific to this compound. In conclusion, the pharmacological inhibition of IGF1R-IRS1/ 2 emerges as a promising therapeutic opportunity for AML with different efficiencies and mechanisms according to the point of intervention, receptor, or cytoplasmic effectors. (AU) | |
| FAPESP's process: | 16/23191-4 - Investigation of IRS2 role on the pathogenesis of myeloproliferative neoplasms JAK2V617F using murine models |
| Grantee: | Juan Luiz Coelho da Silva |
| Support Opportunities: | Scholarships in Brazil - Doctorate |