RESUMO
YAP and TAZ, the Hippo pathway terminal transcriptional activators, are frequently upregulated in cancers. In tumor cells, they have been mainly associated with increased tumorigenesis controlling different aspects from cell cycle regulation, stemness, or resistance to chemotherapies. In fewer cases, they have also been shown to oppose cancer progression, including by promoting cell death through the action of the p73/YAP transcriptional complex, in particular after chemotherapeutic drug exposure. Using HCT116 cells, we show here that oxaliplatin treatment led to core Hippo pathway down-regulation and nuclear accumulation of TAZ. We further show that TAZ was required for the increased sensitivity of HCT116 cells to oxaliplatin, an effect that appeared independent of p73, but which required the nuclear relocalization of TAZ. Accordingly, Verteporfin and CA3, two drugs affecting the activity of YAP and TAZ, showed antagonistic effects with oxaliplatin in co-treatments. Importantly, using several colorectal cell lines, we show that the sensitizing action of TAZ to oxaliplatin is dependent on the p53 status of the cells. Our results support thus an early action of TAZ to sensitize cells to oxaliplatin, consistent with a model in which nuclear TAZ in the context of DNA damage and p53 activity pushes cells towards apoptosis.
Assuntos
Antineoplásicos , Neoplasias do Colo , Via de Sinalização Hippo , Oxaliplatina , Proteínas Serina-Treonina Quinases , Transdução de Sinais , Transativadores , Fatores de Transcrição , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Proteína Supressora de Tumor p53 , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Neoplasias do Colo/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Via de Sinalização Hippo/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Compostos Organoplatínicos/farmacologia , Compostos Organoplatínicos/uso terapêutico , Oxaliplatina/farmacologia , Porfirinas/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Transdução de Sinais/efeitos dos fármacos , Transativadores/metabolismo , Transativadores/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteína Tumoral p73/metabolismo , Proteína Tumoral p73/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/genética , Verteporfina/farmacologia , Verteporfina/uso terapêutico , Proteínas de Sinalização YAP/metabolismoRESUMO
Spleen tyrosine kinase (Syk) expression have been both positively and negatively associated with tumorigenesis. Our goal was to evaluate the contribution of Syk and its two splice variants, full length Syk (L) and short isoform Syk (S), in the tumor biology of colorectal cancer cells (CRC). The analysis of Syk expression in primary human colorectal tumors, as well as the analysis of TCGA database, revealed a high Syk mRNA expression score in colorectal cancer tumors, suggesting a tumor promotor role of Syk in CRC. Our analysis showed that Syk (L) isoform is highly expressed in the majority of the tumor tissues and that it remains expressed in tumors in which global Syk expression is downregulated, suggesting the dependence of tumors to Syk (L) isoform. We also identified a small cluster of tumor tissues, which express a high proportion of Syk (S) isoform. This specific cluster is associated with overexpressed genes related to translation and mitochondria, and down regulated genes implicated in the progression of mitosis. For our functional studies, we used short hairpin RNA tools to target the expression of Syk in CRC cells bearing the activating K-Ras (G13D) mutation. Our results showed that while global Syk knock down increases cell proliferation and cell motility, Syk (L) expression silencing affects the viability and induces the apoptosis of the cells, confirming the dependence of cells on Syk (L) isoform for their survival. Finally, we report the promising potential of compound C-13, an original non-enzymatic inhibitor of Syk isolated in our group. In vitro studies showed that C-13 exerts cytotoxic effects on Syk-positive CRC cells by inhibiting their proliferation and their motility, and by inducing their apoptosis, while Syk-negative cell lines viability was not affected. Moreover, the oral and intraperitoneal administration of C-13 reduced the tumor growth of CRC DLD-1 cells xenografts in Nude mice in vivo.
Assuntos
Neoplasias Colorretais , Splicing de RNA , Animais , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Humanos , Camundongos , Camundongos Nus , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Quinase Syk/genética , Quinase Syk/metabolismoRESUMO
Excessive fat consumption leads to the development of ectopic adipose tissues, affecting the organs they surround. Peripancreatic adipose tissue is implicated in glucose homeostasis regulation and can be impaired in obesity. High palm oil consumption's effects on health are still debated. We hypothesised that crude and refined palm oil high-fat feeding may have contrasting effects on peripancreatic adipocyte hypertrophy, inflammation and lipid oxidation compound production in obese rats. In Wistar rats, morphological changes, inflammation and isoprostanoid production following oxidative stress were assessed in peripancreatic adipose tissue after 12 weeks of diets enriched in crude or refined palm oil or lard (56% energy from fat in each case) versus a standard chow diet (11% energy from fat). Epididymal white and periaortic brown adipose tissues were also included in the study. A refined palm oil diet disturbed glucose homeostasis and promoted lipid deposition in periaortic locations, as well as adipocyte hypertrophy, macrophage infiltration and isoprostanoid (5-F2c-isoprostane and 7(RS)-ST-Δ8-11-dihomo-isofuran) production in peripancreatic adipose tissue. Crude palm oil induced a lower impact on adipose deposits than its refined form and lard. Our results show that the antioxidant composition of crude palm oil may have a protective effect on ectopic adipose tissues under the condition of excessive fat intake.