ABSTRACT
Phosphatidylinositol 3-kinase (PI3K) signaling plays an important role in the regulation of cellular lipid metabolism and non-alcoholic fatty liver disease (NAFLD). However, little is known about the role of the regulatory subunits of PI3K in lipid metabolism and NAFLD. In this study, we characterized the functional role of PIK3R3 in fasting-induced hepatic lipid metabolism. In this study, we showed that the overexpression of PIK3R3 promoted hepatic fatty acid oxidation via PIK3R3-induced expression of PPARα, thus improving the fatty liver phenotype in high-fat diet (HFD)-induced mice. By contrast, hepatic PIK3R3 knockout in normal mice led to increased hepatic TG levels. Our study also showed that PIK3R3-induced expression of PPARα was dependent on HNF4α. The novel PIK3R3-HNF4α-PPARα signaling axis plays a significant role in hepatic lipid metabolism. As the activation of PIK3R3 decreased hepatosteatosis, PIK3R3 can be considered a promising novel target for developing NAFLD and metabolic syndrome therapies.
Subject(s)
Animals , Mice , Diet, High-Fat , Fatty Liver , Lipid Metabolism , Non-alcoholic Fatty Liver Disease , Phenotype , Phosphatidylinositol 3-KinaseABSTRACT
This study examined the synergetic effect of class IA Phosphoinositide 3-kinases catalytic subunit p110β knockdown in conjunction with oxaliplatin treatment on colon cancer cells. Down-regulation of p110β by siRNA interference and oxaliplatin treatment were applied in colon cancer cell lines HT29, SW620 and HCT116. MTT assay was used to measure the inhibitory effect of p110β knockdown on the proliferation of colon cancer cell lines. SubG1 assay and Annexin-V FITC/PI double-labeling cytometry were applied to detect cell apoptosis. And cell cycle was evaluated by using PI staining and flow cytometry. The expression of caspase 3, cleaved PARP, p-Akt, T-Akt and p110β was determined by western blotting. The results suggested that down-regulation of p110β expression by siRNA obviously reduced cell number via accumulation in G(0)-G(1) phase of the cell cycle in the absence of notablely increased apoptosis in colon cancer cell lines HT29 and SW620 (S phase arrest in HCT116). Moreover, inhibition of p110β expression increased oxaliplatin-induced cell apoptosis and cell cycle arrest in HT29, HCT116 and SW620 cell lines. In addition, increases of cleaved caspase-3 and cleaved PARP induced by oxaliplatin treatment were determined by immunoblotting in p110β knockdown group compared with normal control group and wild-type group. It is concluded that down-regulated expression of p110β could inhibit colon cancer cells proliferation and result in increased chemosensitivity of colorectal cancer cells to oxaliplatin through augmentation of oxaliplatin-induced cell apoptosis and cell cycle arrest.
ABSTRACT
This study examined the role of regulated upon activation normal T cell expressed and secreted (RANTES) and its receptor C-C chemokine receptor type 5 (CCR5) in gastric cancer metastasis and the associated mechanism. The expression of RANTES and CCR5 was detected by using immunohistochemical staining and Western blotting in the gastric cancer tissues obtained from 60 gastric cancer patients with or without lymph node metastasis (n=30 in each). The results showed that the expression levels of RANTES and CCR5 were higher in gastric cancer with lymph node metastasis than in that without metastasis (P<0.05). The expression levels of RANTES in 30 lymph nodes with cancerous invasion were higher than in 30 normal lymph nodes (P<0.05). Chemotactic test revealed that the number of migrating gastric cancer cells (n=295.0±54.6) induced by the protein of cancer-invading lymph nodes was greater than that by the protein mixture from cancer-invading lymph nodes and RANTES antibody (n=42.5±11.6) (P<0.05). RT-PCR showed that the expression levels of the main Th1 cytokines (IL-2, Γ-IFN) were lower in gastric cancer with lymph node metastasis (2.22±0.90, 3.26±1.15 respectively) than in that without metastasis (3.07±1.67, 4.77±1.52 respectively) (P<0.05), but the expression level of the main Th 2 cytokine (IL-10) was higher in gastric cancer with lymph nodes metastasis (6.06±2.04) than in that without metastasis (4.88±1.87) (P<0.05). It was concluded that RANTES and its receptor CCR5 may contribute to gastric cancer metastasis through influencing the balance of Th1/Th2. RANTES and CCR5 may become a marker of gastric cancer metastasis.
ABSTRACT
Objective:To investigate the effect of retinoid-interferon-induced mortality (GRIM-19) gene on the apoptosis of colon cancer. Methods: A GRIM-19 eukaryotic expression vector (pCMV-Flag-GRIM-19) was constructed and transfected into SW480 cells. Expressions of GRIM-19 and apoptosis-related proteins were detected by Western blotting analysis. Apoptosis of SW480 cells was measured by Annexin-V/PI assay and mitochondrial membrane potential JC-1 staining. Results: The GRIM-19 eukaryotic expression vector pCMV-Flag-GRIM-19 was successfully constructed. Expression of GRIM-19 in SW480 cells was up-regulated and that of apoptosis-related protein Bcl-xl was down-regulated after transfection with pCMV-Flag-GRIM-19. Apoptosis rate was (7.7±1.39)% in SW480 cells transfected with pCMV-Flag empty vector and (15.0 ± 2.52)% in pCMV-Flag-GRIM-19 transfected cells (P<0.05). Mitochondrial membrane potential was decreased in (7.5±2.09)% of pCMV-Flag transfected cells and (17.5±3.07)% of pCMV-Flag-GRIM-19 transfected cells (P<0.05). Conclusion: In vitro GRIM-19 transfection can effectively induce apoptosis of colon cancer SW480 cells.