OBJECTIVE: To explore the role of miR-593 in regulating the proliferation of colon cancer cells and the molecular mechanism. METHODS: Bioinformatics analysis identified PLK1 as the possible target gene of miR-593. Luciferase assay was employed to verify the binding between miR-593 and PLK1, and qRT-PCR and Western blotting were used to verify that PLK1 was the direct target gene of miR-593. CCK-8 assay was performed to test the hypothesis that miR-593 inhibited the proliferation of colon cancer cells by targeting PLK1. RESULTS: Luciferase assay identified the specific site of miR-593 binding with PLK1. Western blotting showed a significantly decreased expression of PLK1 in the colon cancer cells transfected with miR-593 mimics and an increased PLK1 expression in the cells transfected with the miR-593 inhibitor as compared with the control cells ( < 0.05). The results of qRT-PCR showed no significant differences in the expression levels of PLK1 among the cells with different treatments ( > 0.05). The cell proliferation assay showed opposite effects of miR-593 and PLK1 on the proliferation of colon cancer cells, and the effect of co-transfection with miR-593 mimic and a PLK1-overexpressing plasmid on the cell proliferation was between those in PLK1 over-expressing group and miR-593 mimic group. CONCLUSIONS miR-593 inhibits the proliferation of colon cancer cells by down-regulating PLK1 and plays the role as a tumor suppressor in colon cancer.
Binding Sites ; Cell Cycle Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms ; metabolism ; pathology ; Down-Regulation ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Humans ; In Vitro Techniques ; MicroRNAs ; genetics ; metabolism ; Protein-Serine-Threonine Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sincalide ; metabolism ; Transfection

OBJECTIVE: To investigate the expression of cytokine signal suppressor 3 (SOCS3) in colon cancer tissue and the mechanism by which SOCS3 regulates the proliferation and invasion of colon cancer. METHODS: We collected the specimens of tumor tissues and paired adjacent tissues from 80 patients with colon cancer undergoing radical resection in our hospital between July, 2014 and May, 2017, and the expression of SOCS3 in the tissue samples was analyzed using Western blotting. We also transfected colon cancer cell line SW480 with a SOCS3-overexpressing plasmid or a small interference RNA (siRNA) for SOCS3 knockdown, and the changes in the cell proliferation and invasion capacity were evaluated using CCK-8 assay and Transwell assay, respectively. The effect of demethylation and IL-6 treatment on SOCS3 expression and the proliferation and invasion of SW480 cells were observed. RESULTS: Colon cancer tissues showed a lowered expression of SOCS3 compared with the adjacent tissues. Over-expression of SOCS3 significantly inhibited while SOCS3 knockdown obviously promoted the proliferation and invasion of SW480 cells . Demethylation treatment up-regulated SOCS3 expression and inhibited the proliferation and invasion capacity of SW480 cells; IL-6 treatment of the cells caused the reverse changes. CONCLUSIONS SOCS3 participates in the development and progression of colon cancer and serves as a potential target for colon cancer treatment. In patients with colon cancer, the low expression of SOCS3 possibly as a result of methylation may promote the proliferation and invasion of the cancer cells.
Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms ; etiology ; pathology ; Cytokines ; Demethylation ; Disease Progression ; Humans ; Interleukin-6 ; pharmacology ; Neoplasm Invasiveness ; Neoplasm Proteins ; metabolism ; RNA, Small Interfering ; Signal Transduction ; Suppressor of Cytokine Signaling 3 Protein ; genetics ; metabolism ; Transfection

OBJECTIVE: To investigate the expressions of secreted frizzled-related protein 4 (SFRP4) in stage Ⅱ DNA mismatch repair-deficient (dMMR) and mismatch repair- proficient (pMMR) colorectal cancers and explore their clinical significance. METHODS: We collected fresh stage Ⅱ colon cancer tissues with different MMR status detected by immunohistochemistry (IHC). The differentially expressed mRNAs between dMMR and pMMR tumors were identified by Affymetrix Human oeLncRNA gene chip, and the expression of SFRP4 in these cancer tissues and in colorectal cancer cell lines were detected using Western blotting and real- time quantitative PCR. The apoptosis rates of HCT116 cells with and without siRNA- mediated transient SFRP4 knockdown were determined using flow cytometry. We further investigated the expression pattern of Ki-67 and its correlation with SFRP4 expression. RESULTS: Compared with pMMR colon cancer tissues or cells, both dMMR colon cancer tissues (=0.014) and cells (=0.0079) showed significantly increased expression of SFRP4, which was in negative correlation with Ki-67 (=0.041). In HCT116 cells, transient SFRP4 knockdown resulted in decreased cell apoptosis, including both early apoptosis (=0.003) and late apoptosis (=0.024). CONCLUSIONS Up-regulation of SFRP4 in dMMR stage Ⅱ colon cancer promotes apoptosis and inhibits proliferation of the cancer cells, and may improve the prognosis of dMMR colon cancer.
Apoptosis ; Cell Proliferation ; Colon ; metabolism ; pathology ; Colonic Neoplasms ; genetics ; metabolism ; pathology ; Colorectal Neoplasms ; genetics ; metabolism ; pathology ; DNA Mismatch Repair ; Gene Knockdown Techniques ; HCT116 Cells ; Humans ; Ki-67 Antigen ; metabolism ; Prognosis ; Proto-Oncogene Proteins ; genetics ; metabolism ; Up-Regulation

OBJECTIVETo explore the relationship between DNA mismatch repair (MMR) and clinicopathologic features and prognosis in patients with stages II and III colon cancers.

METHODSThe clinical and pathological data of 440 patients with stage II/III colon cancer after radical resection were retrospectively reviewed and analyzed. Immunohistochemical staining was used to assess the expression of MMR proteins (MLH1, MSH2, MSH6 and PMS2), and the correlation between DNA MMR and clinicopathological features and prognosis of colon cancers was analyzed.

RESULTSOf the 440 tumor samples tested for DNA mismatch repair status, 90 (20.5%) demonstrated defective DNA mismatch repair and 350 (79.5%) had proficient DNA mismatch repair. Defective DNA mismatch repair (dMMR) was associated with young patients (≤ 60), proximal colon cancer, stage II, poorly differentiated adenocarcinoma and mucinous adenocarcinoma (P<0.05 for all). Among the 440 patients, 126 (28.6%) cases had recurrence or metastasis and 93 (21.1%) died during the median follow-up of 61.0 months. The five-year disease-free survival (DFS) rate was 82.2% among the patients with tumor exhibiting dMMR, significantly higher than that in patients with tumors exhibiting pMMR (68.9%, P=0.02). The univariate and mutlivariate analyses showed that the MMR status is an independent factor affecting 5-year disease-free survival and overall survival (OS) in colon cancer patients (P<0.05 for both).

CONCLUSIONSDefective DNA mismatch repair (dMMR) is associated with patients with proximal colon cancer, stage II and poorly defferentiated adenocarcinoma and mucinous adenocarcinoma. The prognosis for patients with dMMR is better than those with pMMR. dMMR may be a useful biomarker for the prognosis of colon cancer.

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma ; genetics ; metabolism ; mortality ; pathology ; Adenocarcinoma, Mucinous ; genetics ; metabolism ; mortality ; pathology ; Adenosine Triphosphatases ; metabolism ; Age Factors ; Analysis of Variance ; Colonic Neoplasms ; genetics ; metabolism ; mortality ; pathology ; DNA Mismatch Repair ; DNA Repair Enzymes ; metabolism ; DNA-Binding Proteins ; metabolism ; Disease-Free Survival ; Humans ; Mismatch Repair Endonuclease PMS2 ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Neoplasm Recurrence, Local ; Nuclear Proteins ; metabolism ; Prognosis ; Retrospective Studies ; Survival Rate

BACKGROUNDHypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha (HIF-1α) plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D (Sema4D) also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages (TAMs) can increase the expression of HIF-1α and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-1α and the impact of biologic behavior in colon cancer cells.

METHODSImmunohistochemistry was used to analyze HIF-1α and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software (SPSS Inc., USA). Differences between two groups were analyzed with Student's t test.

RESULTSHIF-1α (58%) and Sema4D (60%) were expressed at a significantly higher level in tumors than in normal tissues (P < 0.01, for both). Furthermore, HIF-1α and Sema4D expression was significantly correlated with lymphatic metastasis, specific histological types and TNM stages (P < 0.05), but not with age and tumor size (P > 0.05). Sema4D expression was correlated with that of HIF-1α (r = 0.567, P < 0.01). TAMs markedly induced HIF-1α and Sema4D expression in colon cancer cells and subsequently increased their migration and invasion.

CONCLUSIONSHIF-1α and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-1α and Sema4D.

Adult ; Aged ; Antigens, CD ; genetics ; metabolism ; Cell Line, Tumor ; Colonic Neoplasms ; genetics ; metabolism ; Female ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Immunohistochemistry ; Macrophages ; immunology ; metabolism ; Male ; Middle Aged ; Neoplasm Metastasis ; genetics ; pathology ; Semaphorins ; genetics ; metabolism

OBJECTIVESTo study the change of ability to transform from 5'-deoxy-fluorouracil monophosphate (5'-DFUR) to fluorouracil (5-FU) in human colon cancer cell lines SW480 and LOVO which transfected with thymidine phosphorylase (TP) gene. And to discuss the anti-cancer activity of 5'-DFUR to SW480 and LOVO cells.

METHODSTP cDNA were transfected into human colorectal cancer cell lines SW480 and LOVO with the lentiviral vector, pLenti6.3_MCS_IRES2-EGFP. The transfection efficiency was analyzed by flow cytometer, the mRNA expression of TP was detected by RT-PCR, and the TP protein expression was detected by Western blot, and the volumes of 5-FU converted from 5'-DFUR both in 2 cells and medium were detected by high performance liquid chromatography (HPLC). The 50% inhibitory concentration (IC50) of 5'-DFUR on these 2 colon cancer cell lines both wild type and TP-transfected cells were evaluated by MTT assay.

RESULTSThe colorectal cancer cell lines SW480 and LOVO transfected with human TP cDNA were monitored 5 generations, and the transfections efficiency rate wea about 95%. Compared with wild type cell SW480 and LOVO, the RQ values of mRNA expression of SW480-TP and LOVO-TP were (695 ± 171) folds (t = -7.00, P = 0.002) and (282 ± 87) folds (t = -5.61, P = 0.030), respectively. Also TP protein expression in SW480-TP and LOVO-TP were higher than their parent cells shown by Western blot. The volume of 5-FU converted from 5'-DFUR in the medium cultured SW480-TP and LOVO-TP were increased compared with their parent cells, respectively (t = 19.406-66.921, P < 0.01), whereas few of 5-FU was detected both in wild, and TP-transfected cells. After transfected with TP cDNA, the IC50 of 5'-DFUR on SW480-TP and LOVO-TP were (587 ± 17) µmol/L and (1088 ± 89) µmol/L respectively, and there were significantly less than their parent cells (t = -32.59 and -8.52, P < 0.01).

CONCLUSIONSThe stabilized transfections of SW480 and LOVO with higher TP expression could be built with lentiviral vector. Transfected TP cDNA into SW480 and LOVO, could improve the expression both of TP mRNA and TP protein, increase the volume of 5-FU converted from 5'-DFUR in medium, and result in an enhancement of anticancer effect on these 2 cells.

Cell Line, Tumor ; Colonic Neoplasms ; pathology ; Floxuridine ; metabolism ; Fluorouracil ; metabolism ; Humans ; Thymidine Phosphorylase ; genetics ; Transcription, Genetic ; Transfection

OBJECTIVETo explore the expression of hsa-mir-186 in colorectal cancer and study its role in regulating the biological behaviors of human colorectal cancer SW620 cells in vitro.

METHODSThe expression of hsa-miR-186 in colon cancer tissue and the adjacent tissues as well as 5 colon carcinoma cells were analyzed using real-time quantitative RT-PCR. The precursor sequence of miR-186 gene was amplified from the genomic DNA by PCR and cloned into the lentiviral vector PLVTHM labeled with GFP. The colorectal cancer cell line SW620 was transfected with PLVTHM-miR186 vector and the lentivirus-infected cells were sorted with flow cytometry. Cell counting kit-8 (CCK-8) assay was used to detect the proliferation of the cells. The migration and invasion of SW620 cells were investigated using Transwell assay and scratch test. Western blotting was used to detect the expression of YY1 protein in SW620 cell lines.

RESULTSThe relative expression of miR-186 in the cancer tissues was 0.0024∓0.0027, significantly lower than that in the adjacent tissues (0.066∓0.068, P=0.008); the relative expression level of hsa-miR-186 in SW620 and LoVo cells with a high metastatic potential was 0.118∓0.138 and 0.157∓0.001, respectively, significantly lower than that in HT-29 cells with a low metastatic potential (1.000∓0.00, P<0.05). The recombinant lentiviral vector PLVTHM-miR186, verified by enzyme digestion, sequencing and qPCR, caused significant inhibition of cell proliferation, migration and invasion and suppressed the expression of YY1 protein in SW620 cells.

CONCLUSIONAs a tumor suppressor gene, Hsa-miR-186 is down-regulated in colon carcinoma tissues and in highly metastatic SW620 and LoVo cells. Has-miR-186 can inhibit the cell proliferation, migration and invasion of colon carcinoma cells in vitro possibly by suppressing YY1 expression.

Adult ; Aged ; Aged, 80 and over ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Colonic Neoplasms ; genetics ; pathology ; Gene Expression Regulation, Neoplastic ; Genes, Tumor Suppressor ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; MicroRNAs ; Middle Aged ; Transfection ; YY1 Transcription Factor ; metabolism

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

OBJECTIVETo study the role of BH3-only gene in oxaliplatin-induced apoptosis of human colon cancer cell line, and to explore the associated mechanisms.

METHODSTwo strains of human colon cancer cell line SW480 and HT29 were selected, and treated respectively with different concentrations of oxaliplatin (0.3, 0.6, 1.25, 2.5, 5, 10 and 20 mg/L). Cell growth and inhibition were detected by MTT method. Apoptosis was measured by flow cytometry. Bim and PUMA expressions were examined by fluorescence quantitative PCR.

RESULTSAfter treatment of different oxaliplatin concentrations in human colon carcinoma cells SW480 line, the cell growth was inhibited in a dose-dependent manner, while Bim and PUMA expressions were significantly up-regulated. While HT29 cell lines received the same treatment, no obvious inhibition of cell growth and up-regulation of Bim and PUMA expression were found. When SW480 cells were exposed to 5 mg/L and 10 mg/L of oxaliplatin for 24 h, the early apoptotic rates were (4.87±0.55)% and (12.10±1.04)%; for 48 h, the early apoptotic rates were (11.47±0.85)% and (30.07±2.01)%; for 72 h, the early apoptotic rates were (28.99±2.12)% and (38.32±3.15)% respectively, which were all significantly higher than those in control group [(0.30±0.10)%, (0.40±0.10)% and (0.50±0.20)%, all P<0.01]. In HT29 cells, the differences of apoptotic rates between oxaliplatin treatment group and control group were not statistically significant (all P>0.05).

CONCLUSIONSOxaliplatin can inhibit colon cancer cell line SW480 growth and induce apoptosis. Induction of apoptosis of colon cancer cells by oxaliplatin may be associated with the up-regulation of BH3-only proteins, Bim and PUMA.

Apoptosis ; drug effects ; Apoptosis Regulatory Proteins ; metabolism ; Bcl-2-Like Protein 11 ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; pathology ; Humans ; Membrane Proteins ; metabolism ; Organoplatinum Compounds ; pharmacology ; Proto-Oncogene Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism

OBJECTIVETo detect the expression of PSF1 (partner of Sld five 1) in colon cancer specimens, and to explore the effect of RNA interference targeting PSF1 on the proliferation of colon cancer cells and its mechanism.

METHODSExpression level of PSF1 protein in colon cancer specimens was detected by Western blot in 40 patients with colon cancer from May 2004 to December 2006. The short hairpin RNA (shRNA) plasmid targeting PSF1 was transfected into LOVO, HT-29 and HCT116 cells with liposome, then the expression level of PSF1 protein was measured by Western blot, the effect of PSF1 shRNA plasmid transfection on cell proliferation by MTT assay, anchorage-independent growth by soft agar colomy-formation assay, and PSF2, PSF3 and SLD5 mRNA expression by quantitative reverse transcription polymerase chain reaction.

RESULTSThe relative expression level of PSF1 protein in colon cancer tissues was 0.485±0.113, which was significantly higher than that in adjacent normal mucosa tissues (0.056±0.014, P<0.01). Western blot showed that the expression level of PSF1 protein was significantly decreased in colon cancer cells transfected with PSF1 shRNA plasmid. After PSF1 shRNA plasmid transfection, cell proliferation was significantly suppressed, the soft agar colony-forming rates of LOVO, HT-29 and HCT116 cells were significantly lower than those in control groups (P<0.05), meanwhile the expression levels of PSF2, PSF3 and SLD5 mRNA were significantly decreased (P<0.05).

CONCLUSIONSPSF1 is significantly up-regulated in colon cancer tissues compared with adjacent normal mucosa tissues. ShRNA plasmid targeting PSF1 can inhibit the expression of PSF1 gene, suppress the proliferation of colon cancer cells, suggesting that it may be a new therapeutic target for colon cancer.

ATP-Binding Cassette Sub-Family B Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; Adult ; Aged ; Cell Line, Tumor ; Cell Proliferation ; Colonic Neoplasms ; metabolism ; pathology ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Middle Aged ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection