OBJECTIVETo investigate the effects of sphingosine kinase 1 (SphK1) on the proliferation, migration and invasion of human colon cancer LoVo cells, and to explore the related mechanisms.

METHODSHuman colon cancer LoVo cells were divided into three groups: phorbol 12-myristate 13-acetate (PMA) was used to induce the activation of SphK1 in the PMA group, N,N-dimethylsphingosine (DMS) used to suppress the activity of SphK1 in DMS group, and the cells treated with equal amount of 0.9 % NaCl instead of drugs served as the control group. The activity of SphK1 was assayed by autoradiography, the cell proliferation was assessed by MTT assay, cell migration and invasion were examined by Boyden chamber assay, concentrations of sICAM-1 and sVCAM-1 were assayed by ELISA, and RT-PCR and Western blot were used to evaluate the mRNA and protein expression in the cells.

RESULTSThe activity of SphK1 was efficiently induced by PMA and significantly suppressed by DMS. PMA induced cell proliferation in a time- and dose-dependent manner. On the contrast, DMS suppressed cell proliferation in a time- and dose-dependent manner. After treating with PMA, the number of migrating and invasing cells were increased to 143.36 ± 8.73 and 118.46 ± 6.25, significantly higher than those of the control group (75.48 ± 6.12 and 64.19 ± 5.36). After treating with DMS, the number of migrating and invasing cells were decreased to 38.57 ± 3.24 and 32.48 ± 4.27, significantly lower than those of the control group (P < 0.01). The relative expression levels of FAK, ICAM-1 and VCAM-1 mRNA in the PMA group were 0.82 ± 0.06, 0.74 ± 0.05 and 0.89 ± 0.09, and those in the DMS group were 0.23 ± 0.02, 0.26 ± 0.03 and 0.37 ± 0.04, with significant differences between the PMA, DMS and control groups (P < 0.01). Compared with the control group, the relative expression levels of FAK and p-FAK proteins in the PMA group (0.52 ± 0.06 and 0.51 ± 0.06) were significantly elevated, and those of the DMS group (0.20 ± 0.03 and 0.09 ± 0.02) were significantly decreased. In addition, the concentrations of sICAM-1 and sVCAM-1 were significantly elevated with the activation of SphK1. On the contrary, those of the DMS group were significantly reduced with the suppression of SphK1 (Both P < 0.01).

CONCLUSIONSSphK1 may enhance the proliferation, migration and invasion of colon cancer LoVo cells through activating FAK pathway and up-regulating the expression of ICAM-1 and VCAM-1.

Cell Line, Tumor ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; enzymology ; metabolism ; pathology ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Focal Adhesion Kinase 1 ; genetics ; metabolism ; Humans ; Intercellular Adhesion Molecule-1 ; genetics ; metabolism ; Neoplasm Invasiveness ; Phosphorylation ; drug effects ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; RNA, Messenger ; metabolism ; Signal Transduction ; Sphingosine ; analogs & derivatives ; pharmacology ; Tetradecanoylphorbol Acetate ; pharmacology ; Vascular Cell Adhesion Molecule-1 ; genetics ; metabolism

Prebiotics modulate microbial composition and ensure a healthy gastrointestinal tract environment that can prevent colon cancer development. These natural dietary compounds are therefore potential chemopreventive agents. Thirty Sprague-Dawley rats (4 months old) were experimentally treated with procarcinogen dimethylhydrazine to induce colon cancer development. The rats were randomly assigned to three groups: a control group (CG), a group treated with dimethylhydrazine (DMH), and a group given DMH and inulin, a prebiotic (DMH+PRE). The effects of inulin on the activities of bacterial glycolytic enzymes, short-chain fatty acids, coliform and lactobacilli counts, cytokine levels, and cyclooxygenase-2 (COX-2) and transcription nuclear factor kappa beta (NFkappaB) immunoreactivity were measured. Inulin significantly decreased coliform counts (p < 0.01), increased lactobacilli counts (p < 0.001), and decreased the activity of beta-glucuronidase (p < 0.01). Butyric and propionic concentrations were decreased in the DMH group. Inulin increased its concentration that had been reduced by DMH. Inulin decreased the numbers of COX-2- and NFkappaB-positive cells in the tunica mucosae and tela submucosae of the colon. The expression of IL-2, TNFalpha, and IL-10 was also diminished. This 28-week study showed that dietary intake of inulin prevents preneoplastic changes and inflammation that promote colon cancer development.
Animals ; Bacterial Proteins/genetics/metabolism ; Colon/enzymology ; Colonic Neoplasms/chemically induced/*drug therapy/metabolism ; Colony Count, Microbial ; Cyclooxygenase 2/genetics/metabolism ; Cytokines/blood/genetics ; Diet ; Dietary Supplements/analysis ; Dimethylhydrazines/toxicity ; Enterobacteriaceae/drug effects/physiology ; Fatty Acids, Volatile/genetics/metabolism ; Female ; Gene Expression Regulation/drug effects ; Inulin/administration & dosage/*metabolism ; Lactobacillaceae/drug effects/physiology ; Male ; NF-kappa B/genetics/metabolism ; Prebiotics/*analysis ; Rats ; Rats, Sprague-Dawley

Expression of zinc-finger protein 143 (ZNF143), a human homolog of the Xenopus transcriptional activator protein Staf, is induced by various DNA-damaging agents including etoposide, doxorubicin, and gamma-irradiation. ZNF143 binds to cisplatin-modified DNA, and its levels are increased in cancer cells that are resistant to anticancer drugs, including cisplatin, suggesting that it plays a role in carcinogenesis and cancer cell survival. However, the mechanism of ZNF143 induction in cancer cells remains unclear. Both insulin-like growth factor-1 (IGF-1) and its receptor (IGF-1R) have been reported to be overexpressed in cancer cells and to be related to anticancer drug resistance, but the identity of the relevant signaling mediators is still being investigated. In the present study, we observed that IGF-1 was able to induce ZNF143 expression in HCT116 human colon cancer cells and that wortmannin, an inhibitor of phosphatidylinositide 3-kinase (PI3-kinase), inhibited this induction, as did diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, and monodansylcardavarine (MDC), a receptor internalization inhibitor. Treatment with MDC decreased the IGF-1-stimulated generation of reactive oxygen species. Taken together, these data suggest that IGF-1 induces ZNF143 expression in cancer cells via PI3-kinase and reactive oxygen species generation during receptor internalization.
Antineoplastic Agents/pharmacology ; Cell Line, Tumor ; Cisplatin/pharmacology ; Colonic Neoplasms/enzymology/genetics/*metabolism ; HCT116 Cells ; Humans ; Insulin-Like Growth Factor I/*pharmacology ; Phosphatidylinositol 3-Kinase/*metabolism ; Reactive Oxygen Species/*metabolism ; Signal Transduction ; Trans-Activators/*biosynthesis/genetics

OBJECTIVEThis case-control study was designed to detect the association between STK15 Phe31Ile polymorphism and colorectal cancer.

METHODSGenotypes were determined in 283 patients with colorectal cancer and 283 controls. The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression model.

RESULTSThe frequency of the STK15 Ile/Ile genotype was significantly higher in cancer cases than in controls (50.2% vs. 36.8%; P = 0.02). Subjects with the Ile/Ile genotype had an increased risk for the occurrence of colorectal cancer compared with those with the STK15 Phe/Phe genotype (adjusted OR, 1.92; 95% CI, 1.13 - 3.27). No significant association was observed between this STK15 polymorphism and risk of metastasis of the cancer.

CONCLUSIONThese findings suggest that STK15 Phe/Ile polymorphism may be a genetic susceptibility factor for colorectal cancer among Chinese.

Adult ; Aged ; Amino Acid Substitution ; Aurora Kinase A ; Aurora Kinases ; Case-Control Studies ; Colonic Neoplasms ; enzymology ; genetics ; pathology ; Confidence Intervals ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; Genotype ; Humans ; Male ; Middle Aged ; Neoplasm Staging ; Odds Ratio ; Polymorphism, Single Nucleotide ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Rectal Neoplasms ; enzymology ; genetics ; pathology ; Risk Factors

OBJECTIVETo determine whether the eukaryotic initiation factor-4E (eIF-4E) is involved in the cap-dependent translational regulation of heparanase and study the correlation between heparanase expression and metastatic potential of LS-174T cells.

METHODSThe protein and mRNA levels of inhibited eIF-4E were tested by Western blot and RT-PCR. Heparanase activity was defined as the ability to degrade high molecular weight (40-100 000) radiolabeled ((35)S) heparan sulfate (HS) substrate into low molecular weight (5-15 000) HS fragments. The invasive potential of tumor cells in vitro was observed by Matrigel invasion assay system.

RESULTSThe 20-mer antisense oligonucleotide (asODN) against eIF-4E specifically and significantly inhibited eIF-4E expression at both transcriptional and translational levels. The expression and the activity of heparanase were effectively lowered, which further decreased the invasive potential of LS-174T.

CONCLUSIONeIF-4E, probably being involved in translational regulation of heparanase in colon adenocarcinoma cell line LS-174T, can be a particularly interesting target for heparanase regulation, based on of its critical function.

Adenocarcinoma ; enzymology ; pathology ; Cell Line, Tumor ; Colonic Neoplasms ; enzymology ; pathology ; Eukaryotic Initiation Factor-4E ; antagonists & inhibitors ; genetics ; physiology ; Glucuronidase ; metabolism ; Humans ; Neoplasm Invasiveness