With the progress of RNA research techniques, researchers found some different expressions of circular RNA in gastric cancer patients. They have important biological functions that can serve as a "sponge" adsorpting small RNA, can regulate process of alternative splicing and transcription, and can combined with proteins involved in regulating gene expression and mediating the function of protein. A fraction of circular RNA can encode proteins. The circular RNA plays an important regulatory role in tumor cells proliferation, apoptosis, and cycle, but research in gastric cancer is still in infancy. This article reviews the significance, features, biological functions and the role of circular RNA in gastric cancer.

Objective: To investigate the expression of miRNA-1 (miR-1) in colorectal cancer (CRC) tissues and its effect on proliferation and invasion of CRC cells in vitro as well as its mechanism. Methods: A total of 180 CRC tissues from the hospitalized patients who underwent excision surgery and 114 adjacent cancer tissues in the Affiliated Cancer Hospital of Shanxi Medical University between June 2015 and December 2015 were collected. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-1 in 58 cases of CRC tissues and adjacent cancer tissues. Immunohistochemistry was used to detect the expression of stromal cell-derived factor-1 (SDF-1) protein in 122 CRC tissues and effect of overexpression or knockdown of miR-1 on the proliferation, colony formation and invasiveness of DLD1 cells, respectively. Western blot was used to determine the effect of overexpression or knockdown of miR-1 on the expression of SDF-1 in DLD1 cells. Results: RT-qPCR results showed that the expression of miR-1 in CRC tissues was decreased compared with the corresponding adjacent cancer tissues (the relative expression level ratio < 0.5), and the low expression rate of miR-1 in CRC was 82.8% (48/58). Immunohistochemistry results showed that the positive expression rate of SDF-1 in CRC tissues was higher than that in adjacent cancer tissues [81.1% (99/122) vs. 8.9% (5/56), χ² = 82.415, P < 0.01]. Cell function experiment showed that, compared with the control group, the proliferative activity of DLD1 cells that transfected miR-1 mimics was decreased, meanwhile, the colony formation, invasion and SDF-1 expression were reduced (P < 0.05). The proliferative activity, colony formation, invasion and SDF-1 expression in DLD1 cells that transfected miR-1 inhibitor were improved compared with those in the control group (P < 0.05). Conclusions The expression of miR-1 in CRC tissues is low and it may act as a tumor suppressor gene through affecting proliferation and invasive potential of CRC cells by regulating the expression of SDF-1.

Objective: To investigate the expression of INPP4B in gastric cancer and its relationship with clinicopathological features and prognosis. Methods: The expressions of INPP4B mRNA in fresh cancer tissues of 36 patients with gastric cancer and the paracancerous normal gastric mucosa tissues in the Affiliated Cancer Hospital of Shanxi Medical University between July 2014 and December 2014 were detected by using real-time quantitative polymerase chain reaction (RT-qPCR). The expressions of INPP4B protein and its downstream molecule phosphorylation AKT (p-AKT) in paraffin-embedded tumor tissues and the corresponding margin tissues of 49 gastric cancer patients between January 2010 and December 2010 were detected by using immunohistochemistry. The relationship between the expression of INPP4B and clinicopathological features and prognosis was analyzed. Results: RT-qPCR results showed that the expression level of INPP4B mRNA was 0.21±0.04 compared with adjacent cancer normal tissues (t = -2.208, P < 0.05). Immunohistochemistry showed that INPP4B protein was highly expressed in normal margin tissues and lowly expressed in tumor tissues. There was a statistical difference in the positive intensity score between the two groups (u = 4.70, P < 0.01). However, p-AKT protein was overexpressed in tumor tissues and underexpressed in normal margin tissues. There was a statistical difference in the positive intensity score between the two groups (u = 5.77, P < 0.01). The expression of INPP4B and p-AKT protein was negatively correlated (r = -0.644, P < 0.01). The positive expression rate of INPP4B protein in gastric cancer patients was 34.7% (17/49). There were no statistical differences of the positive expression rate of INPP4B protein in gender, age, pathological type, depth of invasion and lymph node metastasis (all P > 0.05). The median overall survival time of patients with INPP4B negative expression was 47 months, and that of patients with INPP4B positive expression was 48 months, and there was no statistical difference (P > 0.05). Conclusion The expression of INPP4B in gastric cancer tissue is low, which may play a role of tumor suppressor in the occurrence and development of gastric cancer by affecting the activity of AKT.

Objective To analyze the effect of miR-497 high expression on the gene expression profile of colon cancer cell line HCT116. Methods MiR-497 high expressing colon cancer cell model HCT116-497 and negative control HCT116-CON were established by lentiviral transduction. The human (V2) gene expression microarray was used to identify genes that were differentially expressed between colon cancer cells overexpressing miR-497 and the controls. The candidates were subjected to the gene ontology (GO) and KEGG pathway enrichment analysis by Molecule Annotation System 3.0 (MAS3.0). The differential expression of representative genes relative to inflammation were confirmed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results Of all the differently expressed genes, 582 genes were down-regulated by at least 3-folds, which were enriched in inflammation-related signaling pathways in colon cancer cells overexpressing miR-497. The decrease in 15 representative genes was validated by qPCR. Compared with those in HCT116-CON cells, expressions of 10 genes in HCT116-497 cells, including CACNB1, FOS, IL-29, RPS6KA2, TNFSF15, IL-11, INHBC, CSF1R, JAK3 and IL-2Rβ, were decreased significantly, and there were statistical differences (all P< 0.05) Conclusion MiR-497 inhibits the mRNA expression of inflammation-related genes in colon cancer cell line HCT116.

Objective To explore the effect of Ginkgo biloba extract (EGb761) on apoptosis of K-ras mutational human colon cancer cells DLD1(DLD1/G13D)and its mechanism. Methods Human colon cancer cell lines DLD1/G13D and DLD1 with K-ras wild type(DLD1/WT)were cultured in vitro,the cell proliferation and apoptosis after 24 h of EGb761 were measured. Proteins involved in related signal pathway were detected by Western blot or ELISA. Results EGb761 reduced cell proliferation and induced cell apoptosis in a concentration-dependent manner in DLD1/WT and DLD1/G13D cells. EGb761 downregulated the expression of RIP1, impaired the phosphorylation of IκB and decreased the level of NF-κB in DLD1/WT and DLD1/G13D cells[DLD1/G13D: (24±4)%, DLD1/WT: (29±9)%(P<0.05). Conclusion EGb761 restrains the proliferation and induces the apoptosis of DLD1/WT and DLD1/G13D cells. The mechanism may be related to the degradation of RIP-1 and inhibition of activation of NF-κB signaling pathway.

Objective To explore the application of serum SELDI proteomic patterns to screen breast cancer biomarkers.Methods Serum protein profiles of 110 breast cancer patients and 100 healthy controls were analyzed with surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOFMS).The spectra were generated on weak cation exchange (WCX2) chips and protein peaks clustering and classification analyses were made using Biomaker Wizard software.Differences in protein intensity between breast cancer cases and controls were measured with the Mann-Whitney U test and adjusted for confounding in a multivariate logistic regression model.Results Forty-nine of these proteins were found to have statistically differential expression levels between breast cancer and normal control sera (P ＜ 0.05).Based on literatures reported,six protein biomarkers,with mass-to-charge ratio (M/Z) (4376,8126,8924,3264,3968,and 9180) were selected.Proteins with M/Z 4376,4126,and 8924 were statistically significantly decreased in breast cancer cases compared to those in healthy controls (P ＜ 0.05).Proteins with M/Z 3264,3968,and 9180 were significantly increased in breast cancer cases compared to those in healthy controls,Protein with M/Z 9180 was associated with TNM stage and Her-2 expression in breast cancer (P ＜ 0.05).Protein with M/Z 8926 was related with lymph node metastasis (P ＜0.05).Conclusion These results suggest that serum SELDI protein profiling can distinguish breast cancer patients from normal subjects with relatively high sensitivity and specificity.SELDI-TOF-MS plays a valuable role in the diagnosis of breast cancer and the discovery of new tumor-specific protein biomarkers.

Objective To find differential expression proteins in patients with T cell non-Hodgkin’ s lymphoma (T-NHL) by using surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF-MS) technique and study their related clinical application value and prospect.Methods Serum protein of 36 T-NHL patients and 30 DLBCL patients were detected by the SELD1-TOF-MS technique and weak cation exchange (wcx-2) chip.Lactate dehydrogenase (LDH) was detected by biochemistry method.Beta2-microglobulin (β2-MG) was detected by enzyme-linked immunesorbent assay (ELISA).The significant different protein spectrometry were analyzed between DLBCL patients and T-NHL patients.The correlation analysis with protein spectrometry,disease staging,LDH and β2-MG were analyzed with Spearman.Results Nine potential candidate proteins,including the peak intensity of M/Z 1142.67,1451.43,1472.49,1512.03,3194.22,3267.41,3933.86,4593.12 and 9182.24,were identified in T-NHL patients.The 9 protein markers had no contact with disease staging of T-NHL (P ＞ 0.05).The protein markers of 4593.12 and 9182.24 were high level in T-NHL patients.LDH in these two protein markers’ positive group [(290.82±29.95) U/L,(283.94±100.94) U/L] was higher than that in negative group [(169.22±55.42) U/L,(169.50±59.25) U/L](t =-3.199,P =0.004; t =-2.378,P =0.026),and LDH was positive correlation with these two protein spectrometry (r =0.265,r =0.178,P ＜ 0.01).There was no statistically significant difference ofβ2-MG between these two protein markers’ positive group and negative group (P ＞ 0.05).The other 7 protein markers were low level in T-NHL patients,and there was no statistically significant difference of LDH and β2-MG in these 7 protein markers (P ＞ 0.05).Conclusion The protein marker of 4593.12 and 9182.24 may be the specific serological markers to identify T-NHL.The combination of these two protein markers and LDH may assess the tumor load,and provide guiding value for clinical treatment.

Objective To explore the application of serum SELDI proteomic patterns to distinguish breast cancer patients from healthy individuals.Methods All serum samples from 101 breast cancer patients and 45 healthy individuals were analyzed by surface-enhanced laser desorption/ionization time-of-fight mass spectrometry (SELDI-TOF-MS).The spectra were generated on weak cation exchange (WCX2) chips,and protein peaks clustering and classification analysis were made using Biomaker Wizard software and Biomarker Pattern software (BPS).Then the pattern was evaluated by blinded test.Results 49 different proteins were found to have statistically differential expression levels between breast cancer and normal control sera (P ＜ 0.05).A diagnostic model consisting of three protein peaks (M/Z 5627,8124 and 2864) could do the best in the diagnosis between breast cancer and healthy individual.When the diagnostic model was tested with the blinded test set,it yielded a positive value of 95 ％ (139/146),a sensitivity of 97 ％ (98/101) and a specificity of 91％ (41/45).Conclusion These results suggested that serum SELDI protein profiling can distinguish breast cancer patients from normal subjects with relatively high sensitivity and specificity.SELDI-TOF-MS plays a valuable role in the diagnosis of breast cancer and the discovery of new tumor-specific protein biomarkers.

Objective To search for differentially expressed proteins in normal ovaries,benign,borderline and malignant ovarian tumor protein. Methods The protein from ovarial carcinoma tissue and benign ovary was drawn, and analyzed with SELDI-TOF MS. Results There are some high expression proteins in ovarian cancer tissues: M/Z 15 112.15, 15 296.79, 7560.78, 16 049.39, 7682.06, 7932.30,15 851.32, 4619.68 and 8052.10. Borderline ovarian tumor protein peak were between benign and malignant:M/Z 15 112.15, 15 851.32, 7560.78, 7682.06 and 7932.30. Conclusion There were some differentially expressed proteins in different ovarian tissue. They might lay the molecular basis for the clinical diagnosis and therapy of ovarian cancer.

Objective To study the expression levels of SCCA1 and SCCA2 mRNA in tissues of cervical squamous cell carcinoma. To investigate the role of this gene in the clinical diagnosis, evaluation of treatment and observation of prognosis of cervical squamous cell carcinoma. Methods Quantitative real-time RT-PCR was used to detect the expression of SCCA1 and SCCA2 mRNA in tissues of 60 cases of cervical squamous cell carcinoma and those of 30 cases of normal cervical tissues. Results The expression level of SCCA2 mRNA in tissues of 30 cases of cervical squamous cell carcinoma was higher than in those of 15 cases of normal cervical tissues (4.405 ± 2.310, 9.088 ± 2.195) (t =-6.513, P ＜0.001), while the expression level of SCCA 1 mRNA did not significantly differ between normal and malignant tissues (P ＞0.05). The expression of SCCA2 mRNA was relevant to FIGO stages and there was a tendency for this gene to increase with the stage getting worse (F =8.313, P ＜0.05). Moreover, the overexpression of SCCA2 mRNA was significantly correlated with lymph node metastases (t =2.853, P ＜0.05). The expression of SCCA2 mRNA was not correlated with age and pathological grading (P ＞0.05). However, the expression of SCCA1 mRNA was not correlated with age,FIGO stages, lymph node metastases and histological grade (P ＞0.05). Conclusion The expression of SCCA2 mRNA may provide help for more accurate diagnosis on the clinical stages and lymph node metastases of cervical squamous cell carcinoma.