ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role of extracellular signal-regulated kinase (ERK) in apoptosis of human colon cancer (HCT116) cells.</p><p><b>METHODS</b>After the HCT116 cells were pretreated with specific ERK inhibitor (U0126) or specific siRNA and exposed to 10 mmol/L sodium butyrate (NaBT) for 24 h, their apoptosis was detected by flow cytometry, levels of SphK2 and ERK protein were measured by Western blot, and translocation of SphK2 was assayed by immunofluorescence microscopy.</p><p><b>RESULTS</b>The U0126 and siRNAs specific for SphK2 blocked the export of SphK2 from nuclei to cytoplasm and increased the apoptosis of HCT116 cells following NaBT exposure. Over-expression of PKD decreased NaBT-induced apoptosis of HCT116 cells, which was reversed by U0126. Furthermore, transfection of HCT116 cells with constitutively activated PKD plasmids recovered the U0126-blocked export of SphK2.</p><p><b>CONCLUSION</b>ERK regulates the export of SphK2 and apoptosis of HCT116 cells by modulating PKD. Modulation of these molecules may help increase the sensitivity of colon cancer cells to the physiologic anti-colon cancer agent, NaBT.</p>
Subject(s)
Humans , Apoptosis , Physiology , Butyric Acid , Pharmacology , Extracellular Signal-Regulated MAP Kinases , Metabolism , HCT116 Cells , Phosphotransferases (Alcohol Group Acceptor) , Genetics , Metabolism , Protein Kinase C , Genetics , Metabolism , RNA, Small Interfering , Signal TransductionABSTRACT
BACKGROUND: 1-8D gene is a member of human 1-8 interferon inducible gene family and is shown to be overexpressed in fresh colon cancer tissues. Three peptides 1-6, 3-5 and 3-7 derived from 1-8D gene were shown to have immunogenicity against colon cancer. METHODS: To study tumor immunotherapy of these peptides we established an adoptive transfer model. D(b-/-)Xbeta2 microglobulin (beta2m) null mice transgenic for a chimeric HLA-A2.1/D(b)-beta2m single chain (HHD mice) were immunized with irradiated peptide-loaded RMA-S/HHD/B7.1 transfectants. Spleens were removed after last immunization, and splenocytes were re-stimulated in vitro. Lymphocytes from vaccinated HHD mice were transferred together with IL-2 to the tumor bearing nude mice that were challenged S.C. with the HCT/HHD/B7 colon carcinoma cell line that was found to grow in these mice. RESULTS: Peptide 3-5 was found to be highly effective in CTL activity. Adoptively transferred anti-peptide 3-5 cytolytic T lymphocytes caused significant retardation in tumor growth. CONCLUSION: This study shows that peptide 3-5 can be the most effective candidate for the vaccine of adoptive immunotherapy against colon cancer.
Subject(s)
Animals , Humans , Mice , Adoptive Transfer , Cell Line , Colon , Colonic Neoplasms , Immunization , Immunotherapy , Immunotherapy, Adoptive , Interferons , Interleukin-2 , Lymphocytes , Mice, Nude , Peptides , Spleen , T-LymphocytesABSTRACT
Colorectal cancer is the most common cancer of the digestive tract in western countries. In Korea, its mortality rate has markedly increased in recent 15 years. The mortality of colon cancer can be decreased by proper screening and subsequent polypectomy. Early colon cancer is defined as colon cancer that infiltrates within mucosa and submucosa regardless of lymph nodes invasion and has favorable outcomes. It can be easily removed by endoscopic procedures. The depth of submucosal invasion should be determined before endoscopic removal by various parameters, such as shape, pit patterns by magnifying endoscopy, and endoscopic ultrasonography. After endoscopic removal, the tissue specimen should be carefully examined for the completeness of the removal.