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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Serine/Arginine protein kinases (SRPKs) são componentes chave da maquinaria de splicing através da regulação por fosforilação das proteínas SR, as quais são cruciais para a seleção dos sítios de splicing alternativo. Entretanto, as SRPKs são frequentemente encontradas superexpressas ou com atividade alterada em diversos tipos de cânceres, inclusive em leucemias. Dessa forma, a busca por pequenas moléculas inibidores destas quinases são de potencial interesse para o delineamento de novas estratégias terapêuticas. Nesta tese, descreve­se a avaliação da inibição farmacológica de SRPKs pelo inibidor seletivo N­(2­ (piperidin­1­il)­5­(trifluorometil)fenil)isonicotinamida (SRPIN340) sobre a viabilidade de linhagens leucêmicas linfoides e mieloides. Além de mostrar atividade citotóxica significativa, o efeito dos tratamentos na regulação da fosforilação das proteínas SR e na alteração da expressão dos genes MAP2K1, MAP2K2, VEGF e FAS foram também identificados. Além disso, a inibição farmacológica de SRPKs foi capaz de desencadear eventos precoces e tardios de apoptose. Por último, estudos de fluorescência intrínseca de triptofano, docking molecular e dinâmica molecular foram analisados a fim de se obter informações estruturais acerca do complexo SRPK/SRPIN340. No segundo estudo, é descrita a síntese de uma série de vinte e duas trifluorometil arilamidas baseadas na estrutura molecular do SRPIN340, além da avaliação dos seus efeitos antileucêmicos. Alguns dos derivados apresentaram efeitos citotóxicos superiores contra linhagens de leucemia mieloide e linfoide em comparação com o SRPIN340. Em particular, os compostos N­(2­(4­bromofenilamino)­5­(trifluorometil)fenil)­2­cloronicotinamida (24), N­(2­(4­bromofenilamino)­5­(trifluorometil)fenil)nicotinamida (30), e N­(2­(4­ bromofenilamino)­5­(trifluorometil)fenil)benzamida (36) apresentaram valores de IC 50 na faixa de 6,0 – 35,7 μM (μmol L ­1 ). Estes três compostos também foram capazes de desencadear eventos de apoptose e autofagia, além de exibir efeito sinergístico em combinação com o agente quimioterápico vincristina. Além disso, o composto 30 se mostrou mais eficiente que o SRPIN340 na diminuição da fosforilação das proteínas SR bem como na diminuição da expressão de isoformas oncogênicas dos genes MAP2K1, MAP2K2, VEGF, e RON. Tomados conjuntamente, estes resultados sugerem que inibidores de SRPKs são capazes de suprimir o crescimento celular através da regulação dos eventos de splicing e podem ser considerados como ponto de partida importante para desenvolvimento de novas estratégias terapêuticas contra leucemias e outros tipos de cânceres. Serine/Arginine protein kinase (SRPK) are key components of the splicing machinery trough the phospho­regulation of SR Proteins, which are crucial for exon selection in the alternative splicing. However, SRPK have frequently been found overexpressed or/and with altered activity in a number of cancers, including leukemias. Thus, the discovery of small molecule inhibitors against these kinases is of potential interest to identify novel therapeutic opportunities. Here, it is described the pharmacological inhibition of SRPK by N­(2­(piperidin­1­yl)­5­ (trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, it was found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. In a second study, it is described the synthesis of a series of twenty­two trifluoromethyl arylamides based on the SRPIN340 scaffold and the evaluation of their antileukemia effects. Some derivatives presented superior cytotoxic effects against myeloid and lymphoid leukemia cell lines compared to SRPIN340. In particular, compounds N­(2­(4­bromophenylamino)­5­(trifluoromethyl)phenyl)­2­chloronicotinamide (24), N­(2­(4­bromophenylamino)­5­(trifluoromethyl)phenyl)nicotinamide (30), and N­(2­(4­ bromophenylamino)­5­(trifluoromethyl)phenyl)benzamide (36) presented IC 50 values within the 6.0 – 35.7 μM (μmol L ­1 ) range. In addition, these three compounds were able to trigger apoptosis and autophagy, and they exhibited synergistic effects in combination with the chemotherapeutic agent vincristine. Moreover, compound 30 was more efficient than SRPIN340 in impairing the intracellular phosphorylation status of SR proteins as well as the expression of MAP2K1, MAP2K2, VEGF, and RON oncogenic isoforms in leukemia cells. Taken together, these results suggest that SRPK pharmacological inhibitors may be considered for the development of novel therapeutic strategies against leukemias and other types of cancers.

The photosynthetic apparatus is targeted by various herbicides, including several amides such as diuron and linuron. Considering the need for the discovery of new active ingredients to cope with weed resistance, the synthesis of a series of trifluoromethyl aryl amides is herein described whose inhibitory properties were assessed in vitro on the photosynthetic electron transport chain, and in vivo on the growth of a model cyanobacterial strain. Theoretical studies were also carried out. Starting with 1‐fluoro‐2‐nitro‐4‐(trifluoromethyl) benzene, the preparation of the amides was achieved via a three‐step sequence, namely nucleophilic aromatic substitution, reduction with SnCl2/HCl, and acylation reactions. The measurement of ferricyanide reduction by functionally intact spinach chloroplasts showed that several derivatives are capable of inhibiting the photosynthetic apparatus. The most active amides presented IC50 values close to 1 μmol L−1, and showed the presence of a 4‐bromophenyl group as a common structural feature. The addition of these brominated amides to the culture medium of a model cyanobacterial strain, Synechococcus elongatus PCC 6301, caused various degrees of growth inhibition. Theoretical studies (molecular modeling and quantitative structure–activity relationship) of all amides and their comparison with some known herbicides confirmed these experimental findings and provided more in‐depth information about the possible molecular target of these compounds. Trifluoromethyl amides herein described, which were shown to act at the PSII level, may represent a novel scaffold to be exploited aiming at the development of new active ingredients for weed control.