ABSTRACT
This study investigated the effects of CpG ODN1826 plus radiotherapy (RT) on tumor growth and angiogenesis of subcutaneous tumor in a rat model. Four treatment groups were tested in which rats were injected with 100 µL CpG ODN1826 (1 µg/µL) or 100 µL vehicle, with and without exposure to 8 Gy after 2 h. At 7 days after inoculation of lung cancer cells, drugs were injected in the tumor and radiation was administered over 5 days, after which the rate of tumor inhibition was calculated. Expression of VEGF-C in tumor tissue was seen in 10, 50, 80, and 100% of tumors in the CpG ODN1826 + RT, CpG ODN1826, vehicle + RT, and vehicle alone groups, respectively, while positive expression of NRP-1 was seen in 10, 40, 90, and 100% of tumors. The decreases in expression of VEGF-C mRNA in the CpG ODN1826 + RT and CpG ODN1826 groups compared with the NS + RT and NS groups were significant (P < 0.01), as were the decreases in NRP-1 mRNA in the CpG ODN1826 + RT group compared with the CpG ODN1826 group (P < 0.01). Thus, CpG ODN1826 can significantly inhibit tumor growth in a rat model, the mechanism of which may be related to inhibition of the expression of VEGF-C and NRP-1, which have an inhibitory effect on angiogenesis.
Subject(s)
Oligodeoxyribonucleotides/pharmacology , Radiation Tolerance/drug effects , Animals , Cell Line, Tumor , Disease Models, Animal , Gene Expression , Humans , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Lung Neoplasms/therapy , Neuropilin-1/genetics , Oligodeoxyribonucleotides/administration & dosage , RNA, Messenger/genetics , Rats , Tumor Burden/drug effects , Tumor Burden/radiation effects , Vascular Endothelial Growth Factor C/genetics , Xenograft Model Antitumor AssaysABSTRACT
The aim of this study was to investigate the expression and clinical significance of cyclooxygenase 2 (COX-2) and vascular en-dothelial growth factor C (VEGF-C) in cholangiocarcinomas at differ-ent clinical and pathological stages. Eighty cholangiocarcinoma sam-ples of patients treated with surgery between January 2012 and January 2014 were collected. Immunohistochemistry was used to detect COX-2 and VEGF-C expression at different clinical and pathological stages. ELISA, real-time PCR, invasive chambers, and MTT assay were ap-plied in cultured cholangiocarcinoma cells treated with a COX-2 inhib-itor. Expression of COX-2 and VEGF-C correlated positively with the clinical TNM stage but did not correlate with the differentiation status. Inhibition of COX-2 activity reduced VEGF-C mRNA expression and secretion in cholangiocarcinoma cells and decreased their migration but not proliferation. Because of its ability to inhibit invasion, COX-2 could be a new target for treatment of cholangiocarcinoma.
Subject(s)
Cholangiocarcinoma/genetics , Cyclooxygenase 2/biosynthesis , Neovascularization, Pathologic/genetics , Vascular Endothelial Growth Factor C/biosynthesis , Cell Line, Tumor , Cell Proliferation/drug effects , Cholangiocarcinoma/drug therapy , Cholangiocarcinoma/pathology , Cholangiocarcinoma/surgery , Cyclooxygenase 2/genetics , Cyclooxygenase 2 Inhibitors/administration & dosage , Gene Expression Regulation, Neoplastic/drug effects , Humans , Neoplasm Staging , Neovascularization, Pathologic/drug therapy , Neovascularization, Pathologic/pathology , Vascular Endothelial Growth Factor C/geneticsABSTRACT
DNA hypomethylation may activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-adenosylmethionine (SAM) is a methyl donor in numerous methylation reactions and acts as an inhibitor of intracellular demethylase activity, which results in hypermethylation of DNA. The main objectives of this study were to determine whether DNA hypomethylation correlated with vascular endothelial growth factor-C (VEGF-C) expression, and the effect of SAM on VEGF-C methylation and gastric cancer growth inhibition. VEGF-C expression was assayed by Western blotting and RT-qPCR in gastric cancer cells, and by immunohistochemistry in tumor xenografts. VEGF-C methylation was assayed by bisulfite DNA sequencing. The effect of SAM on cell apoptosis was assayed by flow cytometry analyses and its effect on cancer growth was assessed in nude mice. The VEGF-C promoters of MGC-803, BGC-823, and SGC-7901 gastric cancer cells, which normally express VEGF-C, were nearly unmethylated. After SAM treatment, the VEGF-C promoters in these cells were highly methylated and VEGF-C expression was downregulated. SAM also significantly inhibited tumor growth in vitro and in vivo. DNA methylation regulates expression of VEGF-C. SAM can effectively induce VEGF-C methylation, reduce the expression of VEGF-C, and inhibit tumor growth. SAM has potential as a drug therapy to silence oncogenes and block the progression of gastric cancer.
Subject(s)
Animals , Humans , Male , Antineoplastic Agents/pharmacology , DNA Methylation/drug effects , Down-Regulation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , S-Adenosylmethionine/pharmacology , Stomach Neoplasms/drug therapy , Vascular Endothelial Growth Factor C/metabolism , Apoptosis/drug effects , Blotting, Western , Cell Line, Tumor , Carcinogenesis/drug effects , DNA Methylation/genetics , Flow Cytometry , Gene Expression Regulation, Neoplastic/physiology , Heterografts/drug effects , Immunohistochemistry , Mice, Nude , Oncogenes/drug effects , Promoter Regions, Genetic/drug effects , Real-Time Polymerase Chain Reaction , RNA, Messenger/analysis , Stomach Neoplasms/metabolism , Vascular Endothelial Growth Factor C/drug effects , Vascular Endothelial Growth Factor C/geneticsABSTRACT
DNA hypomethylation may activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-adenosylmethionine (SAM) is a methyl donor in numerous methylation reactions and acts as an inhibitor of intracellular demethylase activity, which results in hypermethylation of DNA. The main objectives of this study were to determine whether DNA hypomethylation correlated with vascular endothelial growth factor-C (VEGF-C) expression, and the effect of SAM on VEGF-C methylation and gastric cancer growth inhibition. VEGF-C expression was assayed by Western blotting and RT-qPCR in gastric cancer cells, and by immunohistochemistry in tumor xenografts. VEGF-C methylation was assayed by bisulfite DNA sequencing. The effect of SAM on cell apoptosis was assayed by flow cytometry analyses and its effect on cancer growth was assessed in nude mice. The VEGF-C promoters of MGC-803, BGC-823, and SGC-7901 gastric cancer cells, which normally express VEGF-C, were nearly unmethylated. After SAM treatment, the VEGF-C promoters in these cells were highly methylated and VEGF-C expression was downregulated. SAM also significantly inhibited tumor growth in vitro and in vivo. DNA methylation regulates expression of VEGF-C. SAM can effectively induce VEGF-C methylation, reduce the expression of VEGF-C, and inhibit tumor growth. SAM has potential as a drug therapy to silence oncogenes and block the progression of gastric cancer.
Subject(s)
Antineoplastic Agents/pharmacology , DNA Methylation/drug effects , Down-Regulation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , S-Adenosylmethionine/pharmacology , Stomach Neoplasms/drug therapy , Vascular Endothelial Growth Factor C/metabolism , Animals , Apoptosis/drug effects , Blotting, Western , Carcinogenesis/drug effects , Cell Line, Tumor , DNA Methylation/genetics , Flow Cytometry , Gene Expression Regulation, Neoplastic/physiology , Heterografts/drug effects , Humans , Immunohistochemistry , Male , Mice, Nude , Oncogenes/drug effects , Promoter Regions, Genetic/drug effects , RNA, Messenger/analysis , Real-Time Polymerase Chain Reaction , Stomach Neoplasms/metabolism , Vascular Endothelial Growth Factor C/drug effects , Vascular Endothelial Growth Factor C/geneticsABSTRACT
This study aims to investigate MMP2 and MT1-MMP protein as well as VEGF-C and VEGF-D mRNA expression in tumor cells and distant organs considered to be targets for metastasis in a tumor spontaneous metastasis model previously described. Cultured tumor cells, able to express pro-MMP2, MMP2, pro-MMP9, and MT1-MMP, develop tumor growth and metastasis, mainly in the liver and spleen, when they are injected in the mammary pad gland of Wistar rats. Immunohistochemical studies of tumor masses showed small groups of tumor cells staining for MT1-MMP but not for MMP2. In the liver, tumor metastatic foci and a stromal positive staining for both MMP2 and MT1-MMP were shown. The spleen and lymph nodes, with only scattered metastatic cells, did not show MMPs immunostaining. Using RT-PCR, a significantly higher VEGF-C and VEGF-D gene expression was shown in the liver of tumor-bearing rats respect to normal rats, whereas spleen and lymph nodes did not show significant differences in mRNA VEGF-C/D levels. Taken together, our results suggest that the stroma microenvironment of target organs for metastasis has the ability to produce MMPs and VEGFs that facilitate the anchorage of tumor cells and promote tumor cell growth and angiogenesis.