MicroRNAs (miRNAs) are a type of small non-coding RNAs that are often play important roles in carcinogenesis, but the carcinogenic mechanism of miRNAs is still unclear. This study will investigate the function and the mechanism of miR-638 in carcinoma (GC). The expression of miR-638 in GC and the DNA copy number of miR-638 were detected by real-time PCR. The effect of miR-638 on cell proliferation was measured by counting kit-8 assay. Different assays, including bioinformatics algorithms (TargetScan and miRanda), luciferase report assay and Western blotting, were used to identify the target gene of miR-638 in GC. The expression of miR-638 target gene in clinical CRC tissues was also validated by immunohistochemical assay. From this research, we found that miR-638 was downregulated in GC tissues compared with corresponding noncancerous tissues (NCTs), and the DNA copy number of miR-638 was lower in GC than NCTs, which may induce the corresponding downregulation of miR-638 in GC. Ectopic expression of miR-638 inhibited GC cell growth in vitro. Subsequently, we identified that PLD1 is the target gene of miR-638 in GC, and silencing PLD1 expression phenocopied the inhibitory effect of miR-638 on GC cell proliferation. Furthermore, we observed that PLD1 was overexpressed in GC tissues, and high expression of PLD1 in GC predicted poor overall survival. In summary, we revealed that miR-638 functions as a tumor suppressor in GC through inhibiting PLD1.
3' Untranslated Regions ; genetics ; Apoptosis ; genetics ; Base Sequence ; Cell Line, Tumor ; Cell Proliferation ; genetics ; Down-Regulation ; genetics ; Humans ; MicroRNAs ; genetics ; Phospholipase D ; genetics ; Prognosis ; Stomach Neoplasms ; diagnosis ; enzymology ; genetics ; pathology

Although medical treatment has been shown to improve quality of life and prolong survival, no significant progress has been made in the treatment of advanced gastric cancer (AGC) within the last two decades. Thus, the optimum standard first-line chemotherapy regimen for AGC remains debatable, and most responses to chemotherapy are partial and of short duration; the median survival is approximately 7 to 11 months, and survival at 2 years is exceptionally > 10%. Recently, remarkable progress in tumor biology has led to the development of new agents that target critical aspects of oncogenic pathways. For AGC, many molecular targeting agents have been evaluated in international randomized studies, and trastuzumab, an anti-HER-2 monoclonal antibody, has shown antitumor activity against HER-2-positive AGC. However, this benefit is limited to only ~20% of patients with AGC (patients with HER-2-positive AGC). Therefore, there remains a critical need for both the development of more effective agents and the identification of molecular predictive and prognostic markers to select those patients who will benefit most from specific chemotherapeutic regimens and targeted therapies.
Angiogenesis Inhibitors/therapeutic use ; Animals ; Antineoplastic Agents/*therapeutic use ; Humans ; *Molecular Targeted Therapy ; Protein Kinase Inhibitors/therapeutic use ; Receptor, Epidermal Growth Factor/antagonists & inhibitors/metabolism ; Receptor, erbB-2/antagonists & inhibitors/metabolism ; Signal Transduction/drug effects ; Stomach Neoplasms/*drug therapy/enzymology/genetics/pathology ; Treatment Outcome

OBJECTIVETo investigate the association of AKR1B10 expression in gastric cancer tissues with clinicopathologic features and prognosis of gastric cancer patients.

METHODSReal-time polymerase chain reaction (RT-PCR) was conducted to detect AKR1B10 mRNA expression in gastric cancer and adjacent gastric mucosa tissues (n=36). AKR1B10 protein expression was measured by immunohistochemistry in primary gastric cancer tissues (n=100) and non-tumorous gastric mucosa tissues (n=70).

RESULTSRT-PCR results confirmed that AKR1B10 was significantly down-regulated in gastric cancer tissues compared with that in paired adjacent mucosa [8.3% (3/36) vs. 91.7% (33/36), P=0.000]. Immunohistochemistry revealed that the percentage of AKR1B10 positive specimens in gastric carcinoma was lower than that in normal specimens [33.0% (33/100) vs. 92.9% (65/70), P=0.000]. The frequencies of positive AKR1B10 in patients was significantly correlated with tumor size (P=0.000), invasive depth (P=0.004), lymph node metastasis (P=0.028), distant metastasis (P=0.031) and TNM stages (P=0.000). The 5-year survival rate of positive AKR1B10 group was significantly higher as compared to negative group (60.6% vs. 32.8%, P<0.01).

CONCLUSIONThe down-regulation of AKR1B10 expression in gastric cancer may be associated with the progress of gastric cancer is suggestive of poor prognosis.

Adult ; Aged ; Aged, 80 and over ; Aldehyde Reductase ; genetics ; metabolism ; Female ; Gastric Mucosa ; enzymology ; pathology ; Humans ; Male ; Middle Aged ; Prognosis ; RNA, Messenger ; genetics ; Stomach Neoplasms ; diagnosis ; enzymology ; pathology

Animals ; Carcinoma, Squamous Cell ; genetics ; Colorectal Neoplasms ; genetics ; metabolism ; Enzyme Activation ; Esophageal Neoplasms ; genetics ; Genome-Wide Association Study ; Head and Neck Neoplasms ; genetics ; Humans ; Neoplasms ; chemically induced ; enzymology ; genetics ; Phosphoinositide Phospholipase C ; chemistry ; genetics ; metabolism ; physiology ; Signal Transduction ; Skin Neoplasms ; chemically induced ; enzymology ; Stomach Neoplasms ; genetics ; Urinary Bladder Neoplasms ; metabolism ; pathology ; ras Proteins ; metabolism

OBJECTIVETo investigate the effects of silencing heparanase (HPA) on growth, angiogenesis and metastasis of human gastric carcinoma transplanted in nude mice.

METHODSHuman gastric carcinoma SGC-7901 cells and those cells with silenced HPA (gastric carcinoma SGC-7901-HPA(-)) were separately transplanted subcutaneously in 6 nude mice. The time, size and speed of tumor growth were recorded. RT-PCR and Western-blot were used to detect the expression of HPA mRNA and protein in the subcutaneous tumors of the two groups. Immunohistochemical staining was used to detect microvessel density (MVD) in the subcutaneous tumors of the two groups. Cells of the subcutaneous transplanted tumors of the two groups were separately injected into the peritoneal cavity of nude mice, 6 mice each. The growth of metastatic tumors in nude mice was observed.

RESULTSHuman gastric carcinoma SGC-7901 cells and SGC-7901-HPA(-) cells were subcutaneously inoculated in nude mice, and tumors appeared at 4 days and 7 days after inoculation, respectively. The MVD was (20.69 ± 1.20)/HP and (11.35 ± 1.94)/HP, respectively (P < 0.05). The expressions of HPA mRNA and protein of the subcutaneously transplanted SGC-7901-HPA(-) tumor were decreased. Four voluminous metastatic tumors caused by SGC-7901 cells occurred in 3 mice in the liver, right kidney, omentum and intestine. Two smaller abdominal metastatic tumors of SGC-7901-HPA(-) cells were found in the liver and right kidney.

CONCLUSIONSilencing HPA can inhibit the tumor growth, angiogenesis and metastasis of human gastric cancer in nude mice. It suggests that HPA might become a new target for prevention and treatment of gastric cancer.

Adenocarcinoma ; blood supply ; enzymology ; genetics ; pathology ; secondary ; Animals ; Cell Line, Tumor ; Gene Silencing ; Glucuronidase ; biosynthesis ; genetics ; physiology ; Humans ; Kidney Neoplasms ; secondary ; Liver Neoplasms ; secondary ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Microvessels ; pathology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; blood supply ; enzymology ; genetics ; pathology

Rebamipide a gastroprotective drug, is clinically used for the treatment of gastric ulcers and gastritis, but its actions on gastric cancer are not clearly understood. Phospholipase D (PLD) is overexpressed in various types of cancer tissues and has been implicated as a critical factor in inflammation and carcinogenesis. However, whether rebamipide is involved in the regulation of PLD in gastric cancer cells is not known. In this study, we showed that rebamipide significantly suppressed the expression of both PLD1 and PLD2 at a transcriptional level in AGS and MKN-1 gastric cancer cells. Downregulation of PLD expression by rebamipide inhibited its enzymatic activity. In addition, rebamipide inhibited the transactivation of nuclear factor kappa B (NFkappaB), which increased PLD1 expression. Rebamipide or PLD knockdown significantly suppressed the expression of genes involved in inflammation and proliferation and inhibited the proliferation of gastric cancer cells. In conclusion, rebamipide-induced downregulation of PLD may contribute to the inhibition of inflammation and proliferation in gastric cancer.
Alanine/*analogs & derivatives/pharmacology ; Cell Line, Tumor ; Cell Proliferation/drug effects ; Down-Regulation/*drug effects ; Gene Expression Regulation, Neoplastic/*drug effects ; Humans ; Inflammation/*enzymology/genetics/pathology ; Isoenzymes/genetics/metabolism ; NF-kappa B/metabolism ; Phospholipase D/*genetics/metabolism ; Promoter Regions, Genetic/genetics ; Quinolones/*pharmacology ; Stomach Neoplasms/*enzymology/genetics/*pathology ; Transcription, Genetic/drug effects

Humans ; Kisspeptins ; Lymphatic Metastasis ; genetics ; Matrix Metalloproteinase 9 ; genetics ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Stomach Neoplasms ; enzymology ; metabolism ; pathology ; Tumor Suppressor Proteins ; genetics

OBJECTIVETo observe the effect of polo-like kinase 1 (PLK1) gene depletion on mitosis phenotype and elucidate its vital role in gastric cancer cell line (MKN45) mitosis.

METHODSThe PLK1 expression in MKN45 cells was blocked by RNA interference (RNAi), the expression level of PLK1 mRNA and protein were measured by real-time quantitative PCR and Western blot, respectively. The morphological change of microtubules and mitosis phenotype in MKN45 cells were observed by immunofluorescence staining and laser confocal microscopy, the morphological changes of cells were observed by reverse microscopy, the variation of cell cycle distribution was detected by flow-cytometry.

RESULTSAfter RNAi targeting PLK1, PLK1 mRNA and protein level decreased obviously, the cell microtubules became obscure and lost cohesiveness, the mitosis phenotype also varied substantially (P < 0.05), more gastric cancer cells became rounded and showed G(2) phase cell DNA content (P < 0.05).

CONCLUSIONPLK1 gene plays a key role in mitosis and its inhibition can lead to mitosis arrest in MKN45 cells.

Adenocarcinoma ; enzymology ; metabolism ; pathology ; Cell Cycle Proteins ; biosynthesis ; genetics ; Cell Line, Tumor ; G2 Phase ; drug effects ; Humans ; Mitosis ; drug effects ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; Proto-Oncogene Proteins ; biosynthesis ; genetics ; RNA Interference ; RNA, Messenger ; biosynthesis ; genetics ; RNA, Small Interfering ; genetics ; pharmacology ; Stomach Neoplasms ; enzymology ; metabolism ; pathology ; Transfection

OBJECTIVETo observe the effect of polo like kinase 1 (plk1) gene depletion on the growth of gastric cancer cell line-MKN45 cells in vitro and vivo and discuss the feasibility and effectiveness of arranging plk1 as gene therapeutic target for gastric cancer.

METHODSThe plk1 expression of MKN45 cells was inhibited by RNA interference (RNAi). The plk1 mRNA and protein level were measured by real-time quantitative PCR and western blotting, and the change of cell cycle distribution and apoptosis rate were detected by flow-cytometry, and the MKN45 cells proliferation was measured by MTT method. MKN45 cells treated with plk1 siRNA were transplanted subcutaneously in nude mice and their tumorgenesis ability were observed, the plk1 protein levels of the samples from nude mice in different groups were compared.

RESULTSAfter treatment with plk1 siRNA, plk1 mRNA and protein level decreased obviously in certain time, more MKN45 cells accumulated at G(2)/M (P < 0.05). Apoptosis rate of MKN45 cells treated with plk1 siRNA was higher than that of control cells at 48 h and 72 h (P < 0.05), and MKN45 cells proliferated slowly than control groups (P < 0.05), while the tumorgenesis ability obviously decreased, but the plk1 protein levels of the samples from nude mice in different groups were not different.

CONCLUSIONSsiRNA targeting plk1 can inhibit the proliferation of MKN45 cells in vitro and vivo. Plk1 may be a novel therapeutic target for gastric cancer.

Animals ; Apoptosis ; drug effects ; Cell Cycle Proteins ; drug effects ; genetics ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Male ; Mice ; Mice, Nude ; Protein-Serine-Threonine Kinases ; drug effects ; genetics ; Proto-Oncogene Proteins ; drug effects ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; pharmacology ; Stomach Neoplasms ; drug therapy ; enzymology ; pathology ; Transfection

OBJECTIVETo study the correlation between expression of urokinase-type plasminogen activator (uPA) and capability of tumor cell seeding to the peritoneal membrane by different gastric cancer lines.

METHODSExpression of uPA in 4 human gastric cancer cell lines was examined by semi-quantitative RT-PCR, ELISA and Western blot. uPA activity was determined by an assay kit. After ip inoculation of cancer cells to nude mice, tumors on peritoneal membrane was grossly examined for tumor cell seedings.

RESULTSSGC7901 was the highest in uPA expression among human gastric cancer cell lines AGS, SGC7901, MKN45, and MKN28. MKN45 had the strongest uPA activity, while AGS was lowest in both uPA expression and activity. Peritoneal seeding tumors of various sizes were observed in mice inoculated with SGC7901 and MKN45 cells. In addition to peritoneal seedings, bloody ascites was present in mice inoculated with MKN28. The MKN45-inoculated mice took the least time to develop tumors and had the shortest surviving period. No peritoneal seeding was seen in mice inoculated with AGS cells.

CONCLUSIONThree of 4 human gastric cancer cell lines studied express uPA mRNA and activity, which correlate with their peritoneal seeding potentials.

Adenocarcinoma ; enzymology ; secondary ; Animals ; Cell Line, Tumor ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Seeding ; Peritoneal Neoplasms ; secondary ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; enzymology ; pathology ; Urokinase-Type Plasminogen Activator ; biosynthesis ; genetics