HDAC4 promotes the growth and metastasis of gastric cancer via autophagic degradation of MEKK3.

BACKGROUND: Histone deacetylases (HDACs) have been shown to be involved in tumorigenesis, but their precise role and molecular mechanisms in gastric cancer (GC) have not yet been fully elucidated. METHODS: Bioinformatics screening analysis, qRT-PCR, and immunohistochemistry (IHC) were used to identify the expression of HDAC4 in GC. In vitro and in vivo functional assays illustrated the biological function of HDAC4. RNA-seq, GSEA pathway analysis, and western blot revealed that HDAC4 activated p38 MAPK signalling. Immunofluorescence, western blot, and IHC verified the effect of HDAC4 on autophagy. ChIP and dual-luciferase reporter assays demonstrated that the transcriptional regulation mechanism of HDAC4 and ATG4B. RESULTS: HDAC4 is upregulated in GC and correlates with poor prognosis. In vitro and in vivo assays showed that HDAC4 contributes to the malignant phenotype of GC cells. HDAC4 inhibited the MEF2A-driven transcription of ATG4B and prevented MEKK3 from p62-dependent autophagic degradation, thus activating p38 MAPK signalling. Reciprocally, the downstream transcription factor USF1 enhanced HDAC4 expression by regulating HDAC4 promoter activity, forming a positive feedback loop and continuously stimulating HDAC4 expression and p38 MAPK signalling activation. CONCLUSION: HDAC4 plays an oncogenic role in GC, and HDAC4-based targeted therapy would represent a novel strategy for GC treatment.

Expression of Fatty Acid-Binding Protein-3 in Gastrointestinal Stromal Tumors and Its Significance for Prognosis.

BACKGROUND: FABP3 is a member of the fatty acid-binding protein (FABP) family, whose role in various cancers has been reported in the past. However, little is known about the role that FABP3 plays in gastrointestinal stromal tumors (GISTs). METHODS: FABP3 expression was analyzed in 119 patients with GISTs using immunohistochemistry and tissue microarrays to interrogate the relationship between expression and prognosis. Kaplan-Meier analysis was used to calculate patient survival rates using complete follow-up data and to evaluate the potential prognostic value of FABP3 using Cox regression analysis. RESULTS: FABP3-positive signals were detected as brown particles located in the cytoplasm using immunohistochemistry. Among the 119 tissue samples, we observed high FABP3 expression in 64 and low or negative expression in 55. Immunohistochemical analyses suggested that FABP3 expression was significantly correlated with tumor size (P = 0.006), mitotic index (P = 0.016), gross classification (P = 0.048), and AFIP-Miettinen risk classification (P = 0.007). Multiple logistic regression analysis showed that the expression of FABP3 was significantly associated with tumor size (P = 0.021). Kaplan-Meier survival curves showed that patients with GISTs with low expression of FABP3 and classified with a very low to moderate AFIP-Miettinen risk had better prognosis. Multivariate analysis further showed that high expression of FABP3 (P = 0.017) was significantly associated with poor 5-year overall survival. CONCLUSIONS: High FABP3 expression has a prognostic value for patients with GISTs.

SNHG16/miR-605-3p/TRAF6/NF-κB feedback loop regulates hepatocellular carcinoma metastasis.

The mechanism by which miR-605-3p regulates hepatocellular carcinoma (HCC) metastasis has not been clarified. In this study, we found that miR-605-3p was down-regulated in HCC and that low miR-605-3p expression was associated with tumour thrombus and tumour satellites. HCC patients with low miR-605-3p expression showed shorter overall survival and disease-free survival after surgery. Overexpression of miR-605-3p inhibited epithelial-mesenchymal transition and metastasis of HCC through NF-κB signalling by directly inhibiting expression of TRAF6, while silencing of miR-605-3p had the opposite effect. We also found that SNHG16 directly bound to miR-605-3p as a competing endogenous RNA. Mechanistically, high expression of SNHG16 promoted binding to miR-605-3p and inhibited its activity, which led to up-regulation of TRAF6 and sustained activation of the NF-κB pathway, which in turn promoted epithelial-mesenchymal transition and metastasis of HCC. TRAF6 increased SNHG16 promoter activity by activating NF-κB, thereby promoting the transcriptional expression of SNHG16 and forming a positive feedback loop that aggravated HCC malignancy. Our findings reveal a mechanism for the sustained activation of the SNHG16/miR-605-3p/TRAF6/NF-κB feedback loop in HCC and provide a potential target for a new HCC treatment strategy.

HAX-1 promotes the migration and invasion of hepatocellular carcinoma cells through the induction of epithelial-mesenchymal transition via the NF-κB pathway.

The expression of HS-1-associated protein X-1 (HAX-1) plays a major role in the development of hepatocellular carcinoma (HCC). However, the function of HAX-1 in HCC metastasis is unclear. Quantitative real-time PCR and western blotting were used to examine HAX-1 expression in HCC cell lines with different metastatic potential, and in tumor tissues with or without intrahepatic metastasis. HCC tissue arrays (n = 144) were used to assess correlations between clinicopathological parameters and HAX-1 expression. We also examined the effect of HAX-1 on promoting HCC cell metastasis in vivo and in vitro. The results showed that the expression levels of HAX-1 were higher in metastatic HCC cell lines than in non-metastatic HCC cell lines. HAX-1 was also significantly upregulated in primary HCC tissues with intrahepatic metastasis compared with those without intrahepatic metastasis. HCC in patients with high HAX-1 expression is more likely to metastasize. HAX-1 expression was associated with malignant progression and poor prognosis, and HAX1 silencing inhibited HCC cell migration and invasion in vitro and decreased HCC cell lung metastasis in vivo, whereas HAX-1 overexpression had the inverse effect. Moreover, HAX-1 increased HCC cell metastasis by promoting the epithelial-mesenchymal transition (EMT) process. Finally, we revealed that HAX-1 modulated EMT in HCC cells by increasing NF-κB/p65 nuclear translocation. In conclusion, HAX-1 promotes HCC metastasis by EMT through activating the NF-κB pathway, suggesting that HAX-1 could be a potential therapeutic target for HCC treatment.

Rafoxanide promotes apoptosis and autophagy of gastric cancer cells by suppressing PI3K /Akt/mTOR pathway.

Rafoxanide is commonly used as anti-helminthic medicine in veterinary medicine, a main compound of salicylanilide. Previous studies have reported that rafoxanide, as an inhibitor of BRAF V600E mutant protein, inhibits the growth of colorectal cancer, multiple myeloma, and skin cancer. However, its therapeutic effect on gastric cancer (GC) and the potential mechanism has not been investigated. Here, we have found that rafoxanide inhibited the proliferation of GC cells in vitro, arrested the cell cycle in the G0/G1 phase, and promoted apoptosis and autophagy in GC cells. Treatment with specific autophagy inhibitor 3-methyladenine drastically inhibited the apoptotic cell death effect by suppressing the switch from autophagy to apoptosis. Mechanistically, we found that rafoxanide inhibited the growth of GC cells in vitro by inhibiting the activity of the PI3K/Akt/mTOR signaling pathway. This process induced autophagy, which essentially resulted in the apoptosis of GC cells. Results from subcutaneous implanted tumor models in nude mice also indicated that rafoxanide inhibited the growth of GC cells in vivo. Taken together, our findings revealed that rafoxanide inhibited the growth of GC cells both in vitro and vivo, indicating a potential drug candidate for the treatment of GC.

High-level expression of PRSS3 correlates with metastasis and poor prognosis in patients with gastric cancer.

BACKGROUND AND OBJECTIVES: Serine protease-3 (PRSS3) is a known contributor to the genesis and development of malignant tumors, although its role in gastric cancer (GC) is still unclear. METHODS: PRSS3 expression in GC tissue samples and its relationship with clinicopathological features were analyzed. Effects of GC cellular responses to the introduction of small interfering RNA (siRNA)-mediated and short hairpin RNA (shRNA)-mediated interference with tumor PRSS3 expression were also assessed. RESULTS: PRSS3 was significantly upregulated in GC tissues, and PRSS3 protein levels were higher in tumors that developed metastases soon after the surgery compared with those that remained metastasis-free. High expression of PRSS3 was associated with tumor N staging and independently predictive of postoperative prognosis in patients with GC. The V1 variant of PRSS3 was primarily detected in GC tissue and cell lines, the others (V2-V4) being scarcely detectable. Methylation and demethylation drugs had no impact on expression levels of any PRSS3 transcriptional variant. The downregulated PRSS3 expression suppressed GC cell growth, migration, and invasion in vitro and in vivo. CONCLUSIONS: PRSS3 appears to act as an oncogene of GC. High PRSS3 expression portends postoperative metastasis, serving as an effective biomarker of poor therapeutic outcomes.

Low expression of fibulin-1 correlates with unfavorable prognosis in gastric cancer.

The tumor-suppressing role of fibulin-1 has been described in several types of cancers. However, the expression and role of fibulin-1 in the development and progression of gastric cancer (GC) remain largely unknown. In this study, RT-PCR and immunochemistry were used to detect the fibulin-1 expression in GC samples. We have found that the fibulin-1 protein and mRNA levels were downregulated in GC. When investigating the correlation between fibulin-1 expression and clinicopathological characteristics, we have found that low fibulin-1 protein expression was associated with poor tumor differentiation and advanced N stage. Low fibulin-1 protein expression was also an independent prognostic factor for patient survival. To clarify the reason of fibulin-1 downregulation in GC, the mRNA expression and methylation status of fibulin-1 were examined in GC fresh tissue samples (n = 36). We found that the transcriptional expression of fibulin-1 was negatively associated with fibulin-1 promoter hypermethylation, and fibulin-1 hypermethylation was associated with Helicobacter pylori infection. Finally, the effects of fibulin-1 overexpression on cell proliferation and apoptosis were examined. We have found that fibulin-1 overexpression suppressed the growth of GC both in vitro and in vivo and induced apoptosis by increasing cleaved caspase-3 expression. In conclusion, fibulin-1 acts as a tumor suppressor gene, is frequently hypermethylated in GC, and can potentially serve as a useful biomarker for patient prognosis.

The value of serum RASSF10 hypermethylation as a diagnostic and prognostic tool for gastric cancer.

The tumor-suppressing role of Ras-association domain family 10 (RASSF10) has been described in several types of cancers. Here, we evaluated the potential use of the hypermethylation status of the RASSF10 promoter in serum as a new diagnostic and prognostic tool in gastric cancer (GC). We used bisulfite sequencing polymerase chain reaction to examine RASSF10 methylation levels in serum and/or tumor samples from 82 GC, 45 chronic atrophic gastritis (CAG), and 50 healthy control patients. In the serum of GC patients, the median level of RASSF10 methylation was higher at 47.84 % than those in the serum of CAG and healthy control patients at 11.89 and 11.35 %, respectively. The median level of RASSF10 methylation in GC tumor tissue was similarly high at 62.70 %. Furthermore, RASSF10 methylation levels were highly correlated between paired serum and tumor samples from GC patients. We performed receiver-operating characteristic curve analyses to verify that serum RASSF10 methylation levels could effectively distinguish GC from control patients. Moreover, multivariate analyses showed that high serum RASSF10 methylation levels in GC patients were associated with large tumors, lymph node metastasis, and high carcinoembryonic antigen (CEA) levels. Survival analyses showed that GC patients with high serum RASSF10 methylation levels had shorter overall and disease-free survival after D2 lymphadenectomy than those with low levels. High serum RASSF10 methylation levels were also an independent predictor of tumor recurrence and GC patient survival. In conclusion, serum RASSF10 promoter methylation levels can serve as a valuable indicator for the diagnosis and prognosis of GC in the clinic.

RASSF1A hypermethylation is associated with aflatoxin B1 and polycyclic aromatic hydrocarbon exposure in hepatocellular carcinoma.

BACKGROUND/AIMS: RASSF1A hypermethylation is frequently observed in hepatocellular carcinomas (HCC). But the possible related risk factors and prognosis evaluation for this epigenetic alteration are still unknown. METHODOLOGY: Methylation status, mRNA and protein expression of RASSF1A, aflatoxin B1 (AFB1) and polycyclic aromatic hydrocarbon (PAH)-DNA adducts, were examined in 103 cases of HCC. RESULTS: The expression of RASSF1A mRNA (20/103, r=-0.665) and protein (21/103, r=-0.761) were negatively related to RASSF1A hypermethylation (82/103). Multivariate analysis indicated that RASSF1A hypermethylation was related to AFB1- (p=0.046) and PAH-DNA adducts (p=0.040). Other factors including smoking, alcohol drinking, hepatitis B virus infection and clinicopathological parameters were not significantly associated with RASSF1A methylation. No difference in overall survival was observed between patients with and without RASSF1A hypermethylation (p=0.267). CONCLUSIONS: AFB1- and PAH-DNA adducts may be associated with RASSF1A hypermethylation in hepatocarcinogenesis. RASSF1A methylation status may not be a proper predictor of overall survival for HCC.

DNMT1-induced miR-378a-3p silencing promotes angiogenesis via the NF-κB signaling pathway by targeting TRAF1 in hepatocellular carcinoma.

BACKGROUND: Angiogenesis plays an important role in the occurrence, development and metastasis of hepatocellular carcinoma (HCC). According to previous studies, miR-378a participates in tumorigenesis and tumor metastasis, but its exact role in HCC angiogenesis remains poorly understood. METHODS: qRT-PCR was used to investigate the expression of miR-378a-3p in HCC tissues and cell lines. The effects of miR-378a-3p on HCC in vitro and in vivo were examined by Cell Counting Kit-8 (CCK-8), Transwell, tube formation and Matrigel plug assays, RNA sequencing, bioinformatics, luciferase reporter, immunofluorescence and chromatin immunoprecipitation (ChIP) assays were used to detect the molecular mechanism by which miR-378a-3p inhibits angiogenesis. RESULTS: We confirmed that miR-378a-3p expression was significantly downregulated and associated with higher microvascular density (MVD) in HCC; miR-378a-3p downregulation indicated a short survival time in HCC patients. miR-378a-3p knockdown led to a significant increase in angiogenesis in vitro and in vivo. We found that miR-378a-3p directly targeted TNF receptor associated factor 1 (TRAF1) to attenuate NF-κB signaling, and then downregulated secreted vascular endothelial growth factor. DNA methyltransferase 1 (DNMT1)-mediated hypermethylation of miR-378a-3p was responsible for downregulating miR-378a-3p. Moreover, a series of investigations indicated that p65 initiated a positive feedback loop that could upregulate DNMT1 to promote hypermethylation of the miR-378a-3p promoter. CONCLUSION: Our study indicates a novel DNMT1/miR-378a-3p/TRAF1/NF-κB positive feedback loop in HCC cells, which may become a potential therapeutic target for HCC.

Decellularized gastric matrix as a mesh for gastric perforation repair.

The development of novel materials with effective defect-repairing properties will help avoid subtotal gastrectomy in patients with large gastric perforations. We prepared perfused decellularized gastric matrix (PDGM) and analyzed its components, spatial structure, biomechanics, cytotoxicity, and histocompatibility to validate its efficacy in the repair of gastric perforation. PDGM retained large amounts of gastric extracellular matrix, while residual glandular cells and muscle fibers were not found. The spatial structure of the tissue was well preserved, while the DNA and glycosaminoglycan contents were significantly decreased compared with normal gastric tissue (p < .01). There was no obvious deformation of the spatial structure and tissue elasticity of PDGM after sterilization by Cobalt-60 irradiation. The PDGM had good histocompatibility. PDGM was then used to repair a rat gastric perforation model. Radiography of the upper gastrointestinal tract at 24 hr postoperatively revealed no contrast agent leakage. There was evidence of early fibroblast proliferation, which was complicated by capillary regeneration. The hyperplastic gastric gland was slightly disarranged after repair. Defects of the muscular layer also healed a little with the regeneration process. PDGM is a nontoxic biocompatible biological mesh that may be useful for repairing relatively large gastric defects.

Diagnostic and prognostic value of the peripheral natural killer cell levels in gastric cancer.

Peripheral blood lymphocyte subsets have been reported to be useful as prognostic and/or diagnostic markers for patients with cancer. However, the clinical value of peripheral blood lymphocyte subsets in gastric cancer (GC) has remained elusive. In the present study, peripheral CD3+, CD4+ and CD8+ T lymphocytes, B cells (CD19+), regulatory T cells (Tregs; CD4+CD25+CD127-) and natural killer (NK) cells (CD3-CDl6+CD56+) were detected by flow cytometry in 122 patients with GC, 80 healthy donors (HDs) and 80 patients with gastric ulcer (GU). NK cells (CD56+) were detected by immunohistochemical (IHC) analysis in 20 GC and three GU tissue samples. A receiver-operating characteristic (ROC) curve was used to determine the threshold of the peripheral NK cell level and survival analysis was performed to assess its prognostic value in patients with GC. The results indicated that the peripheral NK cell proportion in patients with GC (18.77%) was significantly higher than that in the HD (12.19%) and GU (12.74%) groups. IHC analysis suggested that the NK level in GC tumor samples was correlated with that in paired serum samples. ROC curve analysis indicated that the peripheral NK cell level (15.16%) was able to effectively identify patients with GC, a diagnostic sensitivity of 75.41% and a specificity of 77.45% were determined. Multivariate logistic regression analysis revealed that the peripheral NK cell level was independently associated with the T stage and survival analysis demonstrated that high levels of peripheral NK cells were associated with poor prognosis of patients with GC. In conclusion, the peripheral NK cell level may be a diagnostic and prognostic marker for patients with GC.

High expression of G protein subunit gamma 13 is associated with poor prognosis of gastrointestinal stromal tumor.

The G protein subunit gamma 13 (GNG13) plays an important role in olfaction, vision, and biological behavior. However, our knowledge of the relationship between GNG13 expression and the clinicopathological features of gastrointestinal tumors is insufficient. Therefore, we used the Oncomine database to evaluate the expression of GNG13 mRNA in gastric cancer, the result showed that there was no significant difference in the expression of GNG13 between gastric cancer and adjacent normal tissues, and GNG13 mRNA expression was assessed in 32 matched pairs of Gastrointestinal adenocarcinoma tissues and adjacent normal tissues as well as 32 matched pairs of gastrointestinal stromal tumor (GIST) and adjacent normal tissues by quantitative reverse transcription-polymerase chain reaction analysis. The results suggested that GNG13 is upregulated in gastrointestinal stromal tumors. Immunohistochemical analysis was used to detect the GNG13 in the tissues of 123 patients with GIST. High cytoplasmic expression of GNG13, which was observed in 65.85 % of GIST patients, significantly correlated with mitotic index(P = 0.036) and tumor size(P = 0.024). Multiple logistic regression analysis showed that the expression of GNG13 was significantly associated with tumor size. Kaplan-Meier analysis indicated that high GNG13 expression was associated with poor prognosis of GIST. Multivariate Cox regression analysis indicated that the expression of GNG13, mitotic index and tumor size were independent adverse prognostic factors of GIST. These findings suggest that GNG13 is associated with the malignant phenotype of GIST and may serve as a marker of poor prognosis.

Clinical and prognostic significance of CC chemokine receptor type 8 protein expression in gastrointestinal stromal tumors.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Surgical resection and tyrosine kinase inhibitors are defined as the main treatments but cannot cure patients with advanced GIST, which eventually develops into recurrence and acquired drug resistance. Therefore, it is necessary to identify prognostic biomarkers and new therapeutic targets for GISTs. CC chemokine receptor type 8 (CCR8) protein participates in regulation of immune responses. Recent studies on CCR8 in non-small cell lung cancer and colorectal cancer showed that it was highly expressed in tumor-infiltrating regulatory T cells and correlated with a poor prognosis. AIM: To detect CCR8 expression in GIST tissues and analyze its relationships with clinicopathological features and prognosis in patients with GISTs. METHODS: Tissue samples were used for the tissue microarrays construction. The microarrays were then subjected to immunohistochemical analyses to detect CCR8 expression. Next, Kaplan-Meier analysis was utilized to calculate the survival rate of patients with complete follow-up data, and the potential prognostic value of CCR8 was evaluated by Cox regression analysis. Finally, a Gene Ontology/Kyoto Encyclopedia of Genes and Genomes single-gene enrichment chart of CCR8 was constructed using the STRING database. RESULTS: CCR8-positive signals were detected as brown or brown-yellow particles by immunohistochemistry located in the cytoplasm. Among 125 tissue samples, 74 had CCR8 high expression and 51 had low or negative expression. Statistical analyses suggested CCR8 was significantly correlated with tumor size, mitotic index, AFIP-Miettinen risk classification and tumor location. Kaplan-Meier and multivariate analyses showed that patients with low or negative CCR8 expression, mitotic index < 5/high-power fields (HPF) and tumor diameter < 5 cm had a better prognosis. Based on the STRING database, CCR8 was significantly enriched in biological processes such as tumor immunity, T lymphocyte chemotaxis, migration and pathways like the nuclear factor-κB and tumor necrosis factor pathways as well as intestinal immune regulation networks. CONCLUSION: CCR8 is a prognostic biomarker for malignant potential of GISTs, with high expression correlated with malignancy and poor prognosis.

BDH2 triggers ROS-induced cell death and autophagy by promoting Nrf2 ubiquitination in gastric cancer.

BACKGROUND: 3-Hydroxy butyrate dehydrogenase 2 (BDH2) is a short-chain dehydrogenase/reductase family member that plays a key role in the development and pathogenesis of human cancers. However, the role of BDH2 in gastric cancer (GC) remains largely unclear. Our study aimed to ascertain the regulatory mechanisms of BDH2 in GC, which could be used to develop new therapeutic strategies. METHODS: Western blotting, immunohistochemistry, and RT-PCR were used to investigate the expression of BDH2 in GC specimens and cell lines. Its correlation with the clinicopathological characteristics and prognosis of GC patients was analysed. Functional assays, such as CCK-8 and TUNEL assays, transmission electron microscopy, and an in vivo tumour growth assay, were performed to examine the proliferation, apoptosis, and autophagy of GC cells. Related molecular mechanisms were clarified by luciferase reporter, coimmunoprecipitation, and ubiquitination assays. RESULTS: BDH2 was markedly downregulated in GC tissues and cells, and the low expression of BDH2 was associated with poor survival of GC patients. Functionally, BDH2 overexpression significantly induced apoptosis and autophagy in vitro and in vivo. Mechanistically, BDH2 promoted Keap1 interaction with Nrf2 to increase the ubiquitination level of Nrf2. Ubiquitination/degradation of Nrf2 inhibited the activity of ARE to increase accumulation of reactive oxygen species (ROS), thereby inhibiting the phosphorylation levels of AktSer473 and mTORSer2448. CONCLUSIONS: Our study indicates that BDH2 is an important tumour suppressor in GC. BDH2 regulates intracellular ROS levels to mediate the PI3K/Akt/mTOR pathway through Keap1/Nrf2/ARE signalling, thereby inhibiting the growth of GC.

HCCR-1 is a Novel Prognostic Indicator for Gastric Cancer and Promotes Cell Proliferation.

The role of the human cervical cancer oncogene (HCCR-1) in the development of various tumors has been elucidated; however, its expression and function in gastric cancer remains largely unknown. Accordingly, the expression of HCCR-1 and epidermal growth factor (EGF) were detected in paired gastric cancer tissues and cell lines by western blotting (WB) and immunohistochemistry (IHC). Furthermore, the correlations between HCCR-1 expression in 209 gastric cancer tissues and the clinicopathological features and disease prognosis were analyzed. A stable HCCR-1 overexpression cell line was established, and the influence of increased HCCR-1 expression on the growth of gastric cancer cells was observed in vivo and in vitro. The expression of HCCR-1 generally increased in gastric cancer tissues. Further, increased HCCR-1 expression in gastric cancer tissues was associated with tumor T stage and was an independent factor that influenced poor postoperative prognosis in gastric cancer patients. A positive correlation was also detected between the expression of EGF and HCCR-1 in a time- and dose-dependent manner. The overexpression of HCCR-1 might enhance the growth rate of gastric cancer cells in vitro, increase the number of colony forming units, and promote the growth, volume, and weight of subcutaneous tumors in nude mice. In conclusion, HCCR-1 is a gastric cancer oncogene, and its increased expression plays a critical role in the occurrence and development of gastric cancer. Hence, HCCR-1 could serve as a valuable marker for the postoperative prognostic assessment of gastric cancer patients.

RASSF1A expression inhibits the growth of hepatocellular carcinoma from Qidong County.

BACKGROUND AND AIM: The tumor-suppressing role of Ras-association domain family 1A (RASSF1A) has been described in several systems. In this study, we tested its tumor-suppressing ability and the potential molecular mechanisms in hepatocellular carcinoma (HCC) from Qidong County. METHODS: Reverse transcription polymerase chain reaction and Northern blotting were employed to detect the expression of RASSF1A in HCC. After establishing stable RASSF1A (wild type or mutant) expressing 'qi dong gan ai yan jiu suo' ([Qidong Institute of Liver Cancer] QGY)-7703 cell lines, we tested the effects of RASSF1A expression on cell growth by cell proliferation rate, cell colony formation, and cell cycle progression. We also tested the effects of RASSF1A expression on tumorigenesis in nude mice and on cellular sensitivity to mitomycin treatment. RESULTS: The RASSF1A transcript was not found in 75% (three of four) of HCC cell lines and 67% (32/48) of HCC primary biopsies. The stepwise regression analyses indicated that the loss of RASSF1A expression was more frequent in patients who were hepatitis B virus surface antigen positive (HBsAg+) compared to those who were HBsAg(-), both in tumor and corresponding non-cancerous tissues. The wild-type (wt)-RASSF1A expression in the QGY-7703 cell line resulted in fewer and smaller clones, decreased xenograft tumor volume and weight, and G(1)/S arrest in vitro and in vivo. The wt-RASSF1A expression also decreased the cyclin D1 protein expression, which appeared to be at the level of post-transcriptional control. In addition, the wt-RASSF1A expression increased cell growth inhibition and the percentage of cells with sub-G(1) DNA content when the cells were treated with mitomycin. CONCLUSION: RASSF1A is a tumor suppressor in HCC. The loss of RASSF1A expression may be related to HBsAg+ in hepatocarcinogenesis. Its inactivation may play an important role in the development of HCC.

Low expression of RASSF10 is associated with poor survival in patients with colorectal cancer.

The RASSF10 has been identified as a tumor suppressor in human colorectal cancer (CRC). However, the expression of RASSF10 in patients with CRC has not been evaluated for its potential use as a biomarker in the diagnosis and prognosis assessment of CRC. We analyzed the expression of RASSF10 mRNA (n=30) and protein (n=205) in CRC and matched noncancerous colon tissue samples to explore the relationships among RASSF10 expression, clinicopathological factors, and prognosis in patients with CRC. Our results showed that the expression of RASSF10 mRNA and protein in CRC-adjacent tissues was higher than that in CRC tissues. Low RASSF10 expression was associated with the T stage (P=.037, odds ratio, 0.664; 95% confidence interval, 0.452-0.975) and the N stage (P<.001, odds ratio, 0.318; 95% confidence interval, 0.184-0.549) of the tumors. In addition, univariate analysis revealed that patients with CRC with lower RASSF10 expression had poorer overall survival (OS; P<.001) and disease-free survival (DFS; P<.001). The 5-year OS and DFS rates were 48.2% and 28.3%, respectively, in patients with low RASSF10 expression and 82.2% and 62.6%, respectively, in patients with high RASSF10 expression. Multivariate Cox regression analysis revealed that the strongest predictors of OS and DFS were RASSF10 expression (P<.001 and P<.001, respectively), T stage (P=.003 and P=.009, respectively), and N stage (P=.005 and P=.026, respectively). These results demonstrate that low expression of RASSF10 in CRC tissues is significantly correlated with poor survival after curative resection and may serve as a useful biomarker predictive of CRC prognosis.

Long non-coding RNA CASC2 suppresses the proliferation of gastric cancer cells by regulating the MAPK signaling pathway.

Long non-coding RNAs (lncRNAs) have been shown to play important roles in tumorigenesis. However, the biological functions and molecular mechanisms underlying aberrantly expressed lncRNAs in gastric cancer (GC) is still unclear. In this study, a novel lncRNA CASC2 was chosen to evaluate the effect on GC cell growth and the possible mechanism. Our results showed that CASC2 was significantly downregulated in human GC tissues and cell lines by quantitative RT-PCR. Overexpression of CASC2 in GC cells significantly inhibited the cell growth in vitro and in vivo. We further found that MAPK pathway especially the ERK1/2 and JNK component were involved in the CASC2 mediated GC cell proliferation. Moreover, combination treatment of CASC2 overexpression and suppression ERK1/2 or JNK produced synergistic inhibitory effects in vitro. Thus, these results indicated that CASC2 might serve as a tumor suppressor lncRNA that suppressed cell proliferation by inactivation of MAPK pathway. These findings suggested that CASC2 could be a potential therapeutic target for the treatment of GC patients.

RASSF10 is an epigenetically inactivated tumor suppressor and independent prognostic factor in hepatocellular carcinoma.

Methylation of the Ras-association domain family 10 (RASSF10) promoter region correlates with clinicopathological characteristics and poor prognosis in several human cancers. Here, we examined RASSF10 expression in hepatocellular carcinoma (HCC) and its role in hepatocarcinogenesis. RASSF10 mRNA and protein levels were downregulated in both HCC cell lines and patient tissue samples. In patient tissues, low RASSF10 levels correlated with hepatocirrhosis, poor tumor differentiation, tumor thrombus and Barcelona Clinic Liver Cancer stage, and were indicative of increased tumor recurrence and reduced patient survival. Low RASSF10 expression was associated with promoter hypermethylation, which was in turn associated with polycyclic aromatic hydrocarbon and aflatoxin B1 exposure, but not DNA methyltransferase expression. Overexpression of RASSF10 in HCC cell lines suppressed cell growth and colony formation, and induced apoptosis by up- or down-regulating specific Bcl-2 family proteins. RASSF10 overexpression increased pro-apoptotic Bax and Bad levels, but decreased anti-apoptotic Bcl-2 and Bcl-xl expression. Overexpression also inhibited tumor formation in nude mice and reduced cell migration and invasion by inhibiting the epithelial-mesenchymal transition. RASSF10 knockdown promoted cell growth. Our results show that RASSF10 is frequently hypermethylated and down-regulated in HCC and can potentially serve as a useful biomarker predictive of HCC patient prognosis.