RESUMO
Metastasis associated lung adenocarcinoma transcript 1 (MALAT1) is involved in tumor cell growth process. However, its role and molecular mechanism in liver cancer is still not fully understood. In this study, we found that MALAT1 was significantly expressed in liver cancer cell lines. And knockdown of MALAT1 suppressed proliferation, migration and invasion of HepG2 cells, accompanied with decrease of Rho-associated coiled-coil-forming protein kinase 1 (ROCK1), α-smooth muscle actin (α-SMA), N-cadherin, Vimentin and TWIST. Significantly, MALAT1 deletion sensitized HepG2 cells to 5-FU-induced cell cycle arrest in G1 phase, as evidenced by the significant reduction in Cyclin D1 and CDK4 and increase in p53, p21 and p27 protein levels. In addition, MALAT1 knockdown triggered 5-FU induced apoptosis in HepG2 cells by inducing intrinsic apoptosis-related signals, including Cyto-c, Apaf-1, cleaved Caspase-9/-7/-3 and poly (ADP-ribose) polymerase (PARP). Furthermore, phosphorylated nuclear factor-κB (p-NF-κB) was also down-regulated by MALAT1 silence. Importantly, suppression of IKKα/NF-κB significantly elevated apoptosis and reduced liver cancer cell viability in MALAT1-knockdown cells with 5-FU incubation. The nude mice transplantation model also confirmed the promoted sensitivity of MALAT1-silenced HepG2 cells to 5-FU by blocking tumor cell proliferation and inducing apoptosis. Therefore, our data supplied a potential mechanism by which knockdown of MALAT1 might play an important role in augmenting sensitivity of HepG2 cells to 5-FU in therapeutic approaches, demonstrating suppressing of MALAT1 may serve as a combination with chemotherapeutic agents in liver cancer treatment.
Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Fluoruracila/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , RNA Longo não Codificante/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Células Hep G2 , Humanos , Quinase I-kappa B/metabolismo , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos , Camundongos Nus , NF-kappa B/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
MicroRNA-874 (miR-874), a novel cancer-associated microRNA (miRNA), has been reported to play a suppressive role in multiple malignancies. However, its function in cell migration and invasion in hepatocellular carcinoma (HCC) and the mechanisms responsible remain unclear. Here, we found miR-874 to be significantly downregulated in HCC tissues and cell lines. Moreover, this decreased expression strongly correlated with clinical stage and lymph node metastasis. Accordingly, ectopic expression of miR-874 in HCC cells markedly inhibited their migration, invasion, and epithelial-mesenchymal transition (EMT). Concerning the underlying mechanism, SRY (sex-determining region Y) -box 12 (SOX12) was identified as a direct target of miR-874, and its expression was found to be inversely correlated with that of this miRNA in HCC cells. Importantly, SOX12 knockdown had an inhibitory effect on HCC cells similar to that caused by miR-874 overexpression, whereas SOX12 overexpression in these cells negated the suppressive effects of miR-874 on migration, invasion, and EMT. Overall, these findings demonstrate that miR-874 inhibits metastasis and EMT in HCC by targeting SOX12, suggesting that this miRNA may constitute a promising therapeutic target for this disease.
RESUMO
Hepatic ischemia-reperfusion injury (IRI) is a pathophysiological event post liver surgery or transplantation and significantly influences the prognosis of liver function. The mechanisms of IRI remain unclear, and effective methods are lacking for the prevention and therapy of IRI. Several factors/pathways have been implicated in the hepatic IRI process, including anaerobic metabolism, mitochondria, oxidative stress, intracellular calcium overload, liver Kupffer cells and neutrophils, and cytokines and chemokines. The role of nitric oxide (NO) in protecting against liver IRI has recently been reported. NO has been found to attenuate liver IRI through various mechanisms including reducing hepatocellular apoptosis, decreasing oxidative stress and leukocyte adhesion, increasing microcirculatory flow, and enhancing mitochondrial function. The purpose of this review is to provide insights into the mechanisms of liver IRI, indicating the potential protective factors/pathways that may help to improve therapeutic regimens for controlling hepatic IRI during liver surgery, and the potential therapeutic role of NO in liver IRI.
