LncRNA LINC00974 Downregulates miR-122 to Upregulate RhoA in Oral Squamous Cell Carcinoma.

Background: LncRNA LINC00974 participates in oral fibrogenesis, indicating possible involvement in other oral diseases. Results: The authors found that LINC00974 was upregulated in oral squamous cell carcinoma (OSCC) and predicted poor survival. In OSCC tissues, LINC00974 was inversely correlated with miR-122 and positively correlated with RhoA. In OSCC cells, LINC00974 overexpression resulted in upregulated, whereas overexpression of miR-122 led to downregulated RhoA. Moreover, downregulated miR-122 was observed after LINC00974 overexpression, whereas LINC00974 expression was not significantly affected by miR-122 overexpression. In invasion and migration assay, miR-122 overexpression resulted in reduced, whereas LINC00974 and RhoA overexpression resulted in increased rate of cancer cell migration and invasion. In addition, miR-122 overexpression reduced the effects of LINC00974 overexpression. Conclusion: Therefore, LINC00974 can downregulate miR-122 to upregulate RhoA in OSCC, thereby promoting cell invasion and migration.

MicroRNA-214 promotes the proliferation, migration and invasion of gastric cancer MKN28 cells by suppressing the expression of Dact2.

The present study examined the expression of Dapper, antagonist of ß-catenin 2 (Dact2) and microRNA (miR)-214 in gastric cancer at tissue and cellular levels, and to understand their biological roles. A total of 42 gastric cancer patients were enrolled in the present study. Bioinformatics tool was used to predict the miR molecule that potentially regulates Dact2 expression. To measure the expression of miR-214 and Dact2, reverse transcription-quantitative polymerase chain reaction was employed. Mixed gastric adenocarcinoma type MKN28 cells were transfected with negative control (NC), miR-214 mimics or inhibitor. The CCK-8 assay was used to investigate the proliferation of mixed gastric adenocarcinoma type MKN28 cells. To study migration and invasion abilities of mixed gastric adenocarcinoma type MKN28 cells, the Transwell assay was performed. To determine the expression of Dact2 protein, western blotting was conducted and the rescue assay was utilized to study the biological roles of miR-214 and Dact2 in mixed gastric adenocarcinoma type MKN28 cells. To test whether Dact2 is a direct target of miR-214, the dual luciferase reporter assay was performed. Results indicated that the expression of miR-214 was elevated, but expression of Dact2 mRNA was decreased in gastric cancer tissues, which was closely correlated with the invasion, metastasis, occurrence and development of gastric cancer. Notably, miR-214 promoted the proliferation of mixed gastric adenocarcinoma type MKN28 cells in vitro, whereas but Dact2 inhibited the proliferation of these cells. Downregulation of miR-214 expression or upregulation of Dact2 expression inhibited the migration and invasion of mixed gastric adenocarcinoma type MKN28 cells. Furthermore, miR-214 regulated the expression of Dact2 protein and its downstream ß-catenin protein in mixed gastric adenocarcinoma type MKN28 cells. Dact2 reversed the effect of miR-214 on the proliferation, migration and invasion of mixed gastric adenocarcinoma type MKN28 cells. In addition, miR-214 directly targeted the 3'-UTR seeding region of Dact2 mRNA to regulate its expression. The present study demonstrated that expression of miR-214 was upregulated in gastric cancer tissues, and positively correlated with lymphatic metastasis and clinical staging. In addition, expression of Dact2 was downregulated in gastric cancer tissues and negatively correlated with lymphatic metastasis and clinical staging. Notably, the present findings suggest that miR-214 promoted the proliferation, migration and invasion of mixed gastric adenocarcinoma type MKN28 cells by suppressing the expression of Dact2.

Upregulation of ID2 antagonizes arsenic trioxide-induced antitumor effects in cancer cells.

AIMS AND BACKGROUND: Arsenic trioxide (ATO) strongly induces apoptosis and differentiation in acute promyelocytic leukemia, and induces cell cycle arrest in most solid tumors. Although many signaling pathways are involved in its antitumor mechanism, a detailed investigation of the transforming growth factor beta-bone morphogenetic protein signaling pathway has not been performed. METHODS AND STUDY DESIGN: A microarray containing 113 genes associated with the pathway was used to screen important molecules that participate in the antitumor effects of ATO. The expression levels of the inhibitors of DNA binding-2 (ID2) in 4 different types of cancer cells were determined by quantitative reverse transcription PCR and Western blotting. Human esophageal squamous cell carcinoma cell line Eca109 and pancreatic carcinoma cell line BxPC3 cells were transfected with siRNAs targeting ID2 and scrambled control siRNA. Cell proliferation was evaluated by methyl thiazolyl tetrazolium assay. RESULTS: Eighteen upregulated and 12 downregulated genes were identified. After verification at the transcriptional and translational levels in 4 different cancer cells, ID2 was identified as an ATO antitumor-associated protein. In addition, specific silencing of ID2 could enhance ATO-induced cell proliferation inhibition in cancer cells. CONCLUSIONS: A combination of ATO and ID2-targeted agents may have considerable therapeutic benefits in cancers.

Effect of NF-κB inhibitors on the chemotherapy-induced apoptosis of the colon cancer cell line HT-29.

This study aimed to investigate the impact of the combined use of the nuclear factor-κB (NF-κB) inhibitors pyrrolidine dithiocarbamate (PDTC), bortezomib or SN50, and the chemotherapy agents arsenic acid (As(2)O(3)), fluorouracil (5FU), oxaliplatin or paclitaxel on the growth and apoptosis of HT-29 cells. Cell morphology was observed using inverted microscopy, and cell viability and apoptosis were assessed using the MTT assay and flow cytometry, respectively. The activities of NF-κB were analyzed by western blotting and electrophoretic mobility shift assay (EMSA). Cell growth was significantly inhibited by As(2)O(3), oxaliplatin and paclitaxel in a time- and concentration-dependent manner (P<0.05), while 5FU inhibited cell growth in a time-dependent manner only (P<0.05). The growth inhibition rate and apoptosis induction ratio were increased following the combined treatment of the chemotherapy agent and NF-κB inhibitor. The expression of NF-κB p65 was upregulated when cells were treated with a chemotherapy drug, however it was downregulated following combined treatment or treatment with an NF-κB inhibitor alone. In conclusion, an NF-κB inhibitor combined with a chemotherapy drug effectively inhibited cell proliferation, induced cell apoptosis and inhibited NF-κB activity to enhance the chemotherapeutic sensitivity of HT-29 cells.

The cyclooxygenase-2 inhibitor celecoxib attenuates hepatocellular carcinoma growth and c-Met expression in an orthotopic mouse model.

To demonstrate in vivo tumor growth inhibition, the liver cancer cell lines HepG2, BEL7402, and SMMC7721 were independently inoculated into the livers of 45 6-week-old nude mice. After 24 h, mice were randomly divided into celecoxib (intragastric celecoxib suspension, 300 mg/kg), negative control (equal volume intragastric saline), and positive control (intraperitoneal injection of 6 mg/kg doxorubicin) and treated once per day for 3 days. Body weights, tumor diameters, and tumor expressions of proliferating cell nuclear antigen (PCNA) and c-Met were determined at 23 days posttreatments. Significant increases in body weight were observed in celecoxib- or doxorubicin-treated mice compared to saline-treated animals and tumor growth was significantly attenuated, accompanied by downregulation of tumor PCNA expression (p < 0.01). Weight gain, attenuated tumor growth, and reduced PCNA expression were similar following celecoxib or doxorubicin treatment. Celecoxib also significantly reduced c-Met expression in HepG2- and BEL7402-induced tumors, but not SMMC7721-induced tumors (p < 0.05). In conclusion, celecoxib effectively suppressed the in vivo growth of liver cancer in an orthotopic tumor model. Celecoxib also inhibited tumor cell PCNA expression independent of changes in c-Met expression, with some variability between different implanted cell lines. This preclinical demonstration of celecoxib efficacy and safety provides a foundation for future clinical investigations involving use of this agent alone or as a component of chemotherapeutic regimens for treatment of HCC.

Wnt/beta-catenin signaling pathway may regulate cell cycle and expression of cyclin A and cyclin E protein in hepatocellular carcinoma cells.

Wnt/beta-catenin signaling pathway and cell cycle play the key roles during the genesis and development of hepatocellular carcinoma (HCC). The cytoplasmic protein beta-catenin is a multifunctional protein and a central molecule in the Wnt signaling pathway. Cell cycle is regulated by a a series of regulatory factors. Current researches indicated that expression of cyclin D1 and c-myc decreased after silencing beta-catenin gene in HCC, but it is unclear if other cyclins are affected. To determine the relation, small interference RNA(siRNA) against beta-catenin was transfected into HCC cell line HepG(2), and cell cycle and cyclin A and cyclin E protein expression were detected. We demonstrated that cell cycle was arrested in G(0)/G(1) at 72 h after the transfection and with the time passing, the cell cycle began to transfer from G(0)/G(1) to G(2)/M through S and had a trend to revert at 96 h. In addition, beta-catenin protein expression was decreased at both 72 and 96 h, although the level was slightly higher at 96 h than that at 72 h. However, cyclin A and cyclin E protein expression increased at 72 h and decreased at 96 h. These findings suggest that silencing beta-catenin gene may induce the changes of cell cycle and cyclin A and cyclin E expression. Wnt/beta-catenin signaling pathway probably takes part in the genesis and development of HCC through regulating cell cycle and the expression of cyclin A and cyclin E.