RESUMO
Insulin, as a growth factor, can increase the risk of certain types of cancer. The present study showed that insulin promoted the proliferation of hepatocellular carcinoma cells in vitro and in vivo through pyruvate kinase M2 (PKM2), which is a rate-limiting enzyme in the process of glycolysis. Moreover, the expression of PKM2 was up-regulated by insulin at the posttranslational level in a nuclear orphan receptor TR3-dependent manner. In addition, insulin could enhance the interaction between PKM2 and TR3 and protect PKM2 from degradation. Our results identified a specific mechanism of insulin affecting cancer metabolism and thus promoting cancer progression, and they contribute to a better understanding of the observation that insulin is linked to an increased cancer risk under hyperinsulinemic conditions.
Assuntos
Carcinoma Hepatocelular/genética , Proteínas de Transporte/genética , Insulina/genética , Neoplasias Hepáticas/genética , Proteínas de Membrana/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Hormônios Tireóideos/genética , Carcinogênese/genética , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/genética , Glicólise/genética , Humanos , Insulina/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Proteínas de Ligação a Hormônio da TireoideRESUMO
The tumor microenvironment (TME) has a significant impact on tumor growth and immunotherapy efficacies. However, the precise cellular interactions and spatial organizations within the TME that drive these effects remain elusive. Using advanced multiplex imaging techniques, we have discovered that regulatory T cells (Tregs) accumulate around lymphatic vessels in the peripheral tumor stroma. This localized accumulation is facilitated by mature dendritic cells enriched in immunoregulatory molecules (mregDCs), which promote chemotaxis of Tregs, establishing a peri-lymphatic Treg-mregDC niche. Within this niche, mregDCs facilitate Treg activation, which in turn restrains the trafficking of tumor antigens to the draining mesenteric lymph nodes, thereby impeding the initiation of anti-tumor adaptive immune responses. Disrupting Treg recruitment to mregDCs inhibits tumor progression. Our study provides valuable insights into the organization of TME and how local crosstalk between lymphoid and myeloid cells suppresses anti-tumor immune responses.