RESUMO
Hook1 is a member of the hook family of coiled-coil proteins, which is recently found to be associated with malignant tumors. However, its biological function in hepatocellular carcinoma is yet unknown. Here, we evaluated the Hook1 levels in human hepatocellular carcinoma samples and matched peritumoral tissues by real-time polymerase chain reaction. Small interfering RNA knockdown and a transforming growth factor-ß-induced epithelial-mesenchymal transition model were employed to investigate the biological effects of Hook1 in hepatocellular carcinoma. Our results indicated that Hook1 levels were significantly lower in hepatocellular carcinoma tissues than in the peritumoral tissues. In addition, Hook1 expression was significantly associated with hepatocellular carcinoma malignancy. Hook1 was downregulated after transforming growth factor-ß-induced epithelial-mesenchymal transition. Moreover, Hook1 knockdown promoted epithelial-mesenchymal transition and attenuated the sensitivity of hepatocellular carcinoma cells to doxorubicin. In summary, our results indicate that downregulation of Hook1 plays a pivotal role in hepatocellular carcinoma progression via epithelial-mesenchymal transition. Hook1 may be used as a novel marker and therapeutic molecular target in hepatocellular carcinoma.
Assuntos
Carcinoma Hepatocelular/genética , Transição Epitelial-Mesenquimal/genética , Neoplasias Hepáticas/genética , Proteínas Associadas aos Microtúbulos/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Doxorrubicina/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Neoplásica da Expressão Gênica/genética , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Hepáticas/patologia , Proteínas Associadas aos Microtúbulos/biossíntese , RNA Interferente Pequeno , Fator de Crescimento Transformador beta/genéticaRESUMO
Eukaryotic translation initiation factor 5A2 (eIF5A2) has been identified as a critical gene in tumor metastasis. Research has suggested that reactive oxygen species (ROS) serve as signaling molecules in cancer cell proliferation and migration. However, the mechanisms linking eIF5A2 and ROS are not fully understood. Here, we investigated the effects of ROS on the eIF5A2-induced epithelial-mesenchymal transition (EMT) and migration in six hepatocellular carcinoma (HCC) cell lines. Western hybridization, siRNA transfection, transwell migration assays, wound-healing assays, and immunofluorescence analysis were used. The protein levels of eIF5A2 in tumor and adjacent tissue samples from 90 HCC patients with detailed clinical, pathological, and clinical follow-up data were evaluated. Overexpression of eIF5A2 was found in cancerous tissues compared with adjacent tissues. We found that eIF5A2 overexpression in HCC was associated with reduced overall survival. Knockdown of eIF5A2 and intracellular reduction of ROS significantly suppressed the invasion and metastasis of HCC cells. Interestingly, N1-guanyl-1, 7-diaminoheptane (GC7) suppressed the intracellular ROS levels. After blocking the EMT, administration of GC7 or N-acetyl-L-cysteine did not reduce cell migration further. Based on the experimental data, we concluded that inhibition of eIF5A2 alters progression of the EMT to decrease the invasion and metastasis of HCC cells via ROS-related pathways.
Assuntos
Carcinoma Hepatocelular/metabolismo , Movimento Celular , Neoplasias Hepáticas/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Transição Epitelial-Mesenquimal/genética , Guanina/análogos & derivados , Guanina/farmacologia , Células Hep G2 , Humanos , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Invasividade Neoplásica , Fatores de Iniciação de Peptídeos/genética , Interferência de RNA , Proteínas de Ligação a RNA/genética , Transdução de Sinais , Fator de Iniciação de Tradução Eucariótico 5ARESUMO
Hepatocellular carcinoma (HCC) is one of the most common and therapeutically challenging malignancies worldwide. For patients ineligible for "curative resection" or liver transplantation, chemotherapy is an important minimally effective option. Strategies for chemosensitization are urgently needed. Here, we report that LB-100, a serine/threonine protein phosphatase 2A (PP2A) inhibitor, enhances the cytotoxicity of chemotherapy for HCC in vitro and in vivo. We found that LB-100 significantly enhanced inhibition of HCC by doxorubicin and cisplatin in vitro and in vivo in a PP2A-dependent way, while having little inhibitory activity when used alone. LB-100 promoted vascular endothelial growth factor secretion and vasculogenic mimicry, associated with increased microvessel density and blood perfusion of tumor cell xenografts. LB-100 also enhanced paracellular endothelial permeability to Evans Blue dye and doxorubicin in vivo and in vitro, presumably by altering vascular endothelial-cadherin contact between cells. Changes in permeability and perfusion were accompanied by increased accumulation of doxorubicin in HCC xenografts but not in normal liver tissue. In conclusion, LB-100 enhances chemotherapy by interfering with DNA damage-induced defense mechanisms and by increasing angiogenesis and drug penetration into tumor cells. The induction of angiogenesis and vascular permeability of tumor xenografts by inhibition of PP2A may be a novel approach for enhancing the cytotoxic treatment of HCC and potentially other cancers.
