RESUMO
Studies have showed that there are many biological targets related to the cancer treatment, for example, TGF type I receptor (TGF-ßRI or ALK5). The ALK5 inhibition is a strategy to treat some types of cancer, such as breast, lung, and pancreas. Here, we performed CoMFA and CoMSIA studies for 70 ligands with ALK5 inhibition. The internal validation for both models (q(2)LOO = 0.887 and 0.822, respectively) showed their robustness, while the external validations showed their predictive power (CoMFA: r(2)test = 0.998; CoMSIA: r(2)test = 0.975). After all validations, CoMFA and CoMSIA maps indicated physicochemical evidences on the main factors involved in the interaction between bioactive ligands and ALK5. Therefore, these results suggest molecular modifications to design new ALK5 inhibitors.
Assuntos
Ligantes , Modelos Moleculares , Proteínas Serina-Treonina Quinases/química , Receptores de Fatores de Crescimento Transformadores beta/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Sítios de Ligação , Simulação por Computador , Desenho de Fármacos , Humanos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Relação Quantitativa Estrutura-Atividade , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Reprodutibilidade dos TestesRESUMO
The transforming growth factor- ß (TGF- ß ) superfamily is a family of structurally related proteins that includes TGF- ß , activins/inhibins, and bone morphogenic proteins (BMPs). Members of the TGF- ß superfamily regulate cellular functions such as proliferation, apoptosis, differentiation, and migration and thus play key roles in organismal development. TGF- ß is involved in several human diseases, including autoimmune disorders and vascular diseases. Activation of the TGF- ß receptor induces phosphorylation of serine/threonine residues and triggers phosphorylation of intracellular effectors (Smads). Once activated, Smad proteins translocate to the nucleus and induce transcription of their target genes, regulating various processes and cellular functions. Recently, there has been an attempt to correlate the effect of TGF- ß with various pathological entities such as allergic diseases and cancer, yielding a new area of research known as "allergooncology," which investigates the mechanisms by which allergic diseases may influence the progression of certain cancers. This knowledge could generate new therapeutic strategies aimed at correcting the pathologies in which TGF- ß is involved. Here, we review recent studies that suggest an important role for TGF- ß in both allergic disease and cancer progression.
Assuntos
Hipersensibilidade/genética , Hipersensibilidade/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Animais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Humanos , Família Multigênica , Neoplasias/patologia , Ligação Proteica , Biossíntese de Proteínas , Isoformas de Proteínas , Multimerização Proteica , Proteólise , Receptores de Fatores de Crescimento Transformadores beta/química , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta/químicaRESUMO
Betaglycan is a coreceptor for members of the transforming growth factor beta (TGF-beta) superfamily. Mutagenesis has identified two ligand binding regions, one at the membrane-distal and the other at the membrane-proximal half of the betaglycan ectodomain. Here we show that partial plasmin digestion of soluble betaglycan produces two proteolysis-resistant fragments of 45 and 55 kDa, consistent with the predicted secondary structure, which indicates an intervening nonstructured linker region separating the highly structured N- and C-terminal domains. Amino terminal sequencing indicates that the 45 and 55 kDa fragments correspond, respectively, to the membrane-distal and -proximal regions. Plasmin treatment of membrane betaglycan results in the production of equivalent proteolysis-resistant fragments. The 45 and 55 kDa fragments, as well as their recombinant soluble counterparts, Sol Delta10 and Sol Delta11, bind TGF-beta, but nonetheless, compared to intact soluble betaglycan, have a severely diminished ability to block TGF-beta activity. Surface plasmon resonance (SPR) analysis indicates that soluble betaglycan has K(d)'s in the low nanomolar range for the three TGF-beta isoforms, while those for Sol Delta10 and Sol Delta11 are 1-2 orders of magnitude higher. SPR analysis further shows that the K(d)'s of Sol Delta11 are not changed in the presence of Sol Delta10, indicating that the high affinity of soluble betaglycan is a consequence of tethering the domains together. Overall, these results suggest that betaglycan ectodomain exhibits a bilobular structure in which each lobule folds independently and binds TGF-beta through distinct nonoverlapping interfaces and that linker modification may be an approach to improve soluble betaglycan's TGF-beta neutralizing activity.
Assuntos
Testes de Neutralização , Fragmentos de Peptídeos/metabolismo , Proteoglicanas/química , Proteoglicanas/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/química , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Células COS , Chlorocebus aethiops , Espaço Extracelular/química , Espaço Extracelular/metabolismo , Fibrinolisina/metabolismo , Humanos , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína/genética , Proteoglicanas/antagonistas & inibidores , Proteoglicanas/genética , Receptores de Fatores de Crescimento Transformadores beta/antagonistas & inibidores , Receptores de Fatores de Crescimento Transformadores beta/genética , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Solubilidade , Relação Estrutura-Atividade , Fator de Crescimento Transformador beta/químicaRESUMO
Betaglycan, a cell surface heparan sulphate proteoglycan, is traditionally thought to function by binding transforming growth factor type beta (TGF-beta) via its core protein and then transferring the growth factor to its signaling receptor, the type II receptor. However, there is increasing evidence that the function of betaglycan is more complex. Here, we have evaluated the role of betaglycan through adenoviral expression (Adv-BG) in myoblasts and fibroblasts and found that in Adv-BG-infected cells, the activity of p3TP-Lux and pCTGF-Luc reporter after transient transfection, as well as fibronectin synthesis, all of which are target processes for TGF-beta, were highly increased in the absence of TGF-beta. It is known that this cytokine strongly inhibits myogenin induction in myoblasts. In Adv-BG-infected myoblasts, the activity of pMyo-Luc reporter after transient transfection was strongly inhibited in the absence of TGF-beta. These effects were not precluded by applying TGF-beta-blocking antibodies, the soluble TGF-beta type II receptor, or soluble betaglycan to sequester TGF-beta present in the cell medium. Furthermore, the data suggest that the cytoplasmic domain of betaglycan is required for this TGF-beta-independent response, giving further support to a ligand-independent signaling effect for betaglycan. The process also seemed independent of Smad-2 phosphorylation, although Adv-BG infection induced p38 phosphorylation, and SB239063, an inhibitor of the p38 pathway, inhibited p3TP-Lux-driven activity. These results suggest a novel signaling mechanism for betaglycan, which is independent of the canonical TGF-beta signal pathway although it involves TGF-beta receptors and takes place through p38 pathways.