RESUMO
The "free radical theory of aging" suggests that reactive oxygen species (ROS) are responsible for age-related loss of cellular functions and, therefore, represent the main cause of aging. Redox regulation by thioredoxin-1 (TRX) plays a crucial role in responses to oxidative stress. We show that thioredoxin-interacting protein (TXNIP), a negative regulator of TRX, plays a major role in maintaining the redox status and, thereby, influences aging processes. This role of TXNIP is conserved from flies to humans. Age-dependent upregulation of TXNIP results in decreased stress resistance to oxidative challenge in primary human cells and in Drosophila. Experimental overexpression of TXNIP in flies shortens lifespan due to elevated oxidative DNA damage, whereas downregulation of TXNIP enhances oxidative stress resistance and extends lifespan.
Assuntos
Envelhecimento/genética , Proteínas de Transporte/fisiologia , Proteínas de Ciclo Celular/fisiologia , Dano ao DNA/genética , Estresse Oxidativo/genética , Adulto , Idoso , Envelhecimento/metabolismo , Animais , Proteínas de Transporte/genética , Proteínas de Ciclo Celular/genética , Células Cultivadas , Drosophila melanogaster , Células HEK293 , Humanos , Células Jurkat , Longevidade/genética , Pessoa de Meia-Idade , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Tiorredoxinas/metabolismo , Regulação para Cima/genética , Adulto JovemRESUMO
Chemotherapy is one of the pillars of anti-cancer therapy. Although chemotherapeutics cause regression of the primary tumor, many chemotherapeutics are often shown to induce or accelerate metastasis formation. Moreover, metastatic tumors are largely resistant against chemotherapy. As more than 90% of cancer patients die due to metastases and not due to primary tumor formation, novel drugs are needed to overcome these shortcomings. In this study, we identified the anticancer phytochemical Rocaglamide (Roc-A) to be an inhibitor of cancer cell migration, a crucial event in metastasis formation. We show that Roc-A inhibits cellular migration and invasion independently of its anti-proliferative and cytotoxic effects in different types of human cancer cells. Mechanistically, Roc-A treatment induces F-actin-based morphological changes in membrane protrusions. Further investigation of the molecular mechanisms revealed that Roc-A inhibits the activities of the small GTPases RhoA, Rac1 and Cdc42, the master regulators of cellular migration. Taken together, our results provide evidence that Roc-A may be a lead candidate for a new class of anticancer drugs that inhibit metastasis formation.
