Comprehensive Multiomics Analyses Establish the Optimal Prognostic Model for Resectable Gastric Cancer : Prognosis Prediction for Resectable GC.

BACKGROUND: Prognostic models based on multiomics data may provide better predictive capability than those established at the single-omics level. Here we aimed to establish a prognostic model for resectable gastric cancer (GC) with multiomics information involving mutational, copy number, transcriptional, methylation, and clinicopathological alterations. PATIENTS AND METHODS: The mutational, copy number, transcriptional, methylation data of 268, 265, 226, and 252 patients with stages I-III GC were downloaded from the TCGA database, respectively. Alterations from all omics were characterized, and prognostic models were established at the individual omics level and optimized at the multiomics level. All models were validated with a cohort of 99 patients with stages I-III GC. RESULTS: TTN, TP53, and MUC16 were among the genes with the highest mutational frequency, while UBR5, ZFHX4, PREX2, and ARID1A exhibited the most prominent copy number variations (CNVs). Upregulated COL10A1, CST1, and HOXC10 and downregulated GAST represented the biggest transcriptional alterations. Aberrant methylation of some well-known genes was revealed, including CLDN18, NDRG4, and SDC2. Many alterations were found to predict the patient prognosis by univariate analysis, while four mutant genes, two CNVs, five transcriptionally altered genes, and seven aberrantly methylated genes were identified as independent risk factors in multivariate analysis. Prognostic models at the single-omics level were established with these alterations, and optimized combination of selected alterations with clinicopathological factors was used to establish a final multiomics model. All single-omics models and the final multiomics model were validated by an independent cohort. The optimal area under the curve (AUC) was 0.73, 0.71, 0.71, and 0.85 for mutational, CNV, transcriptional, and methylation models, respectively. The final multiomics model significantly increased the AUC to 0.92 (P < 0.05). CONCLUSIONS: Multiomics model exhibited significantly better capability in predicting the prognosis of resectable GC than single-omics models.

A 5-serum miRNA panel for the early detection of colorectal cancer.

OBJECTIVE: The study aimed to screen microRNAs (miRNAs) that can be used for the early detection of colorectal cancer (CRC) based on differential expression of miRNA in serum. MATERIALS AND METHODS: A three-stage study was designed with a total of 217 CRCs, 168 colorectal adenomas (CRAs), and 190 healthy controls (HCs). A quantitative reverse transcription polymerase chain reaction was performed in three stages. We screened 528 miRNA expression profiles in the sera of 40 patients (CRC n=20, CRA n=10, and HC n=10) for candidate miRNAs, then 210 serum samples (CRC n=90, CRA n=60, and HC n=60) were used for screening of candidate miRNAs. Three hundred and twenty-five independent individual samples (CRC n=107, CRA n=98, and HC n=120) were used to validate the most differentially-expressed miRNAs in the screening stage, and binary logistic regression was used in the validation stage. A receiver operating characteristic curve was drawn to evaluate the diagnostic accuracy. RESULTS: A 5-serum miRNA panel (miRNA-1246, miRNA-202-3p, miRNA-21-3p, miRNA-1229-3p, and miRNA-532-3p) effectively distinguished CRCs from HCs with 91.6% sensitivity and 91.7% specificity. The area under the curve (AUC) was 0.960 (95% confidence interval [CI]: 0.937-0.983). In addition, the panel also accurately distinguished CRCs from CRAs with 94.4% sensitivity and 84.7% specificity. The AUC was 0.951 (95% CI: 0.922-0.980). CONCLUSION: Our 5-serum miRNA panel accurately distinguished CRCs from CRAs and HCs with high sensitivity and specificity. The 5-serum miRNA panel may be a promising prospect for application as a nonintrusive and inexpensive method for the early detection of CRC.

RKIP promotes cisplatin-induced gastric cancer cell death through NF-κB/Snail pathway.

The objectives of this study were to explore the expression profiles of Raf kinase inhibitor protein (RKIP) in human gastric cancer cell line (SGC-7901) and cisplatin-resistant cell line (SGC-7901/DDP) and investigate the role of RKIP in the sensitivity of human gastric cancer cells to cisplatin and its signaling pathways, with an attempt to identify new approaches and strategies for the management of gastric cancer. The human gastric cancer cell line (SGC-7901) and cisplatin-resistant cell line (SGC-7901/DDP) were separately cultured in vitro. The expression profiles of RKIP in these two cell lines were detected by Western blotting. Forty-eight hours after the transfection of RKIP siRNA in SGC-7901 cells, the change of RKIP expression in the cells was detected using Western blotting, and the change of cell viability after the interference of RKIP expression was determined using 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) method. The effect of the ectopic expression of RKIP on the cisplatin-induced viability of gastric cancer cell was detected using MTT method. The effect of the ectopic expression of RKIP on the cisplatin-induced apoptosis of gastric cancer cell was detected using flow cytometry after having been double stained with Annexin V/PI. The effect of the ectopic expression of RKIP on the NF-κB and Snail expressions in cisplatin-induced gastric cancer cells was detected using Western blotting. As shown by the Western blotting, the expression of RKIP in SGC-7901/DDP cells significantly decreased when compared with that in SGC-7901 cells (P < 0.05). Compared with the control group, the expression of RKIP in SGC-7901 cells significantly decreased 48 h after the transfection of RKIP siRNA (P < 0.01). After the SGC-7901 cells were transfected with RKIP siRNA, the cell viability was significantly increased (P < 0.05); after the SGC-7901/DDP cells were transfected with RKIP recombinant plasmid, the cell viability was significantly decreased (P < 0.05). After the RKIP expression was suppressed in the cisplatin-treated SGC-7901 cells, the cell viability significantly increased (P < 0.05), and the amount of apoptotic cells significantly decreased (P < 0.05). In contrast, after the RKIP overexpression in the cisplatin-treated SGC-7901/DDP cells, the cell viability significantly decreased (P < 0.05), and the amount of apoptotic cells significantly increased (P < 0.05). The suppression of RKIP expression in SGC-7901 cells could significantly promote the increase of NF-κB expression (P < 0.05); in contrast, the increased expression of RKIP in SGC-7901/DDP cells significantly inhibited the expression of Snail (P < 0.05). The expression of RKIP is downregulated in cisplatin-resistant cell line (SGC-7901/DDP). The overexpression of RKIP can enhance the sensitivity of human gastric cancer cells to cisplatin, which may be achieved via the NF-κB/Snail signaling pathway.

RKIP inhibits gastric cancer cell survival and invasion by regulating the expression of HMGA2 and OPN.

The objective of this study was to explore the mechanism via which Raf kinase inhibitor protein (RKIP) suppresses the invasion of gastric cancer cells and promote apoptosis, with an attempt to provide evidences for the application of RKIP in treating gastric cancer. The recombinant plasmid pcDNA3.1-RKIP or RKIP-shRNA was transfected into the gastric cancer cell line SGC-7901 using liposome. Then, the messenger RNA (mRNA) and protein expressions of RKIP, HMGA2, and OPN were detected using qPCR and Western blotting. The effects of HMGA2 on the proliferation, apoptosis, and invasion of SGC-7901 cells were detected using flow cytometry and Transwell assay. To further explore the regulatory effect of PKIP on the biological activities of HMGA2, we over-expressed or knock down RKIP and HMGA2 simultaneously and detected its effects on the proliferation, apoptosis, and invasion of SGC-7901 cells. As shown by qPCR and Western blotting, after over-expression of RKIP in SGC-7901 cells, the mRNA and protein expressions of RKIP significantly increased (P < 0.01), whereas the mRNA and protein expressions of HMGA2 and OPN significantly decreased (P < 0.01). In contrast, the transfection of RKIP-shRNA in the SGC-7901 cells resulted in opposite results. After over-expression of HMGA2 in SGC-7901 cells, the protein expression of HMGA2 significantly increased (P < 0.01); however, it significantly decreased after the transfection of HMGA2-shRNA (P < 0.01). As shown by Transwell assay and flow cytometry, After the over-expression of HMGA2 in SGC-7901 cells, the (G2 + S) phase fraction significantly increased (P < 0.01); also, the percentage of the apoptotic cells significantly declined (P < 0.05) and the number of invasive cells significantly increased (P < 0.05). However, the interference of the expression of HMGA2 resulted in opposite results. The simultaneous over-expression of RKIP and HMGA2 in SGC-7901 cells or the simultaneous interference of RKIP and HMGA2 showed no significant difference with the control group in terms of (G2 + S) phase fraction, percentage of apoptotic cells, and number of invasive cells (P > 0.05). In conclusion, RKIP can inhibit the survival and invasion of gastric cancer cells and promote apoptosis, possibly by regulating the expression of HMGA2 or OPN.

RKIP suppresses gastric cancer cell proliferation and invasion and enhances apoptosis regulated by microRNA-224.

The purposes of this study were to determine the expression profile of Raf kinase inhibitor protein (RKIP) in human gastric cancer cells and its effect on the biological characteristics of SGC-7901 cell lines, to examine the modulatory effect of microRNA-224 (miR-224) on RKIP. The research will provide novel strategies for gastric cancer treatment in the future. Quantitative real-time reverse transcription PCR (qRT-PCR) was employed to determine the expression profile of RKIP in gastric cancer cell lines (SGC-7901, MGC80-3, and MKN45). A eukaryotic expression vector, pcDNA3.1-RKIP, was constructed and transfected into SGC-7901 cells. Changes in RKIP protein expression were examined by Western blot assays, and the effect of RKIP overexpression on SCG-7901 cell viability was determined by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide (MTT) assays. The effect of RKIP overexpression on SGC-7901 cell proliferation and apoptosis was analyzed by flow cytometry and that on the migration of SGC-7901 cells was investigated by Transwell migration assays. RKIP was identified to be a regulatory target gene of miR-224 using a luciferase reporter gene system, and the effect of miR-224 on intracellular RKIP protein expression was examined by Western blot assays. The regulatory effect of miR-224 on the biological characteristics of RKIP was investigated by MTT, flow cytometry, and Transwell invasion chamber assays. The expression of RKIP in gastric cancer cells was decreased significantly in comparison to that of normal gastric mucosal epithelial cells (GES-1) (p < 0.01), as demonstrated by qRT-PCR assays. Compared with the control group, the up-regulation of RKIP intracellular expression was observed in SGC-7901 cells after transfection of pcDNA3.1-RKIP for 48 h (p < 0.01). There were significant decreases in cell viability and the S-phase fraction (p < 0.05), concomitant with a significant increase in apoptosis (p < 0.01), as well as a significant reduction in cells migrating through Transwell chambers (p < 0.05), as shown by MTT, flow cytometry, and Transwell invasion chamber assays. A significant decrease in luciferase activities in cells transfected with a miR-224 mimic was observed compared with that of the control group (p < 0.05), as suggested by the luciferase reporter gene system. As shown by Western blot assays, there was a significant decrease in RKIP expression in SGC-7901 cells transfected with the miR-224 mimic for 48 h compared with the control group (p < 0.05). As shown by MTT, flow cytometry, and Transwell invasion chamber assays, the changes in biological characteristics induced by RKIP overexpression could be suppressed in SGC-7901 cells after transfection of the miR-224 mimic. In conclusion, the down-regulation of RKIP expression was observed in human gastric cell lines, and miR-224 could negatively regulate the expression and biological characteristics of RKIP, contributing to suppress the proliferation and invasion of gastric cells.

[Effect of delayed-release 5-fluorouracil implants on colorectal cancer].

OBJECTIVE: To study the antitumor effect of peri-tumor implantation of delayed-release 5-fluorouracil implants on xenograft colorectal tumor in mice. METHODS: Fifty tumor-bearing nude mice were randomly divided into 5 groups. Group A and B were treated with peri-tumor implantation of 5-fluorouracil implants and the dose of 5-fluorouracil was 200 and 100 mg/kg, respectively. Group C and D were treated with peri-tumor injection of 5-fluorouracil solution and the dose of 5-fluorouracil was 200 and 100 mg/kg, respectively. Group E did not receive any treatment. A growth curve was plotted for changes in tumor volume, the weight of the tumor was measured and tumor inhibition rate was calculated. RESULTS: The growth curve was mild in group A and B and steep in group C, D and E. There were statistical differences in tumor volume between groups A and B and other groups and there were no statistical differences in tumor volume among group C, D and E. After 12 days, tumor inhibition rate was 72% in group A, 51% in group B, 8% in group C, and 5% in group C. There were statistical differences in inhibition rate between group A, B and C, D (P<0.05). The weight changes before and after the treatment among the 5 groups were not statistically different. During the study, 1 mouse in group A died, 4 in group C and 1 in group D. CONCLUSION: Delayed-release 5-fluorouracil implants can effectively inhibit tumor growth.