[PCID2 is highly expressed in gastric cancer and affects the prognosis by regulating cancer cell cycle and proliferation]

OBJECTIVE

To investigate the expression of PCI Domain Containing 2 (PCID2) in gastric cancer, its effect on gastric cancer cell cycle and proliferation and the possible molecular mechanisms.

METHODS

We examined PCID2 expression levels in gastric cancer and adjacent tissues from 100 patients undergoing radical gastrectomy in our hospital between January, 2012 and December, 2016, and analyzed the correlation of PCID2 expression level with cancer progression and postoperative 5-year survival rate of the patients. GO enrichment analysis was performed to identify the possible pathways that mediated the effect of PCID2 in gastric cancer progression. The effects of lentivirus-mediated PCID2 knockdown and overexpression on cell proliferation and cell cycle were analyzed in gastric cancer MGC-803 cells and in nude mice.

RESULTS

PCID2 was highly expressed in gastric cancer tissues and positively correlated with peripheral blood levels of CA19-9 and CEA (P < 0.01). In gastric cancer patients, a high PCID2 expression was associated with a significantly lowered postoperative 5-year survival rate (P < 0.001) as an independent risk factor for postoperative survival (HR: 2.987, 95% CI: 1.616-5.519). The sensitivity, specificity, and area under the curve of PCID2 for predicting postoperative 5-year survival were 76.74%, 75.44%, and 0.755 (P < 0.001), respectively. GO enrichment analysis suggested that PCID2 was associated with gastric cancer cell cycle progression. PCID2 overexpression in MGC-803 cells significantly promoted cell proliferation, G1/S phase transition, expressions of cyclin D1 and CDK6, and the growth of transplanted xenograft in nude mice (P < 0.05). The expressions of p27 and p16 were significantly lowered in gastric cancer tissues, and their expression levels were negatively regulated by PCID2 expression in MGC-803 cells (P < 0.05).

CONCLUSION

PCID2 is highly expressed in gastric cancer tissues in close correlation with poor prognosis of the patients. High PCID2 expression promotes gastric cancer proliferation and cell cycle progression by inhibiting the expression of p27 and p16.

[Construction of a fecal protein Luminex liquid chip detection system for early diagnosis of colorectal tumors]

OBJECTIVE

To construct a stool-based human protein diagnostic system using the Luminex liquid chip system for early diagnosis of colorectal tumors.

METHODS

From January, 2021 to January, 2023, 70 patients with colorectal cancer (CRC), 42 patients with colorectal adenoma (CRA), and 38 healthy individuals were recruited from our hospital for detecting fecal protein levels of matrix metalloproteinase-9 (MMP-9), retinol-binding protein 4 (RBP4), chitinase-3-like protein 1 (CHI3L1), and complement component 3a (C3a) using Luminex liquid chip technology and serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) using chemiluminescence assay. Receiver-operating characteristic (ROC) curve analysis was used for assessing the diagnostic efficacy of the combination of MMP-9, RBP4, CHI3L1 and C3a and the combination of CEA and CA19-9 for colorectal tumors.

RESULTS

The fecal contents of MMP-9, RBP4, CHI3L1, and C3a were significantly higher in CRC patients than in healthy individuals (P < 0.05). Fecal MMP-9 and CHI3L1 levels were significantly higher in CRC than in CRA patients (P < 0.05), but RBP4 and C3a levels did not differ significantly (P>0.05). CRC patients had significantly higher serum CEA and CA19-9 levels than healthy individuals and CRA patients (P < 0.05), but the differences were not significant between the latter two groups (P>0.05). ROC analysis showed that the sensitivity and specificity of the combination of MMP-9, RBP4, CHI3L1, and C3a was 91.4% and 100.0%, for diagnosing CRC, 81.0% and 89.5% for diagnosing CRA, and 83.9% and 97.4% for a combined diagnosis of CRC and CRA, respectively. Z-test analysis indicated that fecal MMP-9, RBP4, CHI3L1, and C3a contents had a greater diagnostic efficacy than serum tumor markers CEA and CA19-9 for a combined diagnosis of colorectal tumors (P < 0.05).

CONCLUSION

The Luminex liquid chip detection system for detecting decal RBP4, MMP-9, CHI3L1, and C3a provides an effective means for early diagnosis of colorectal tumors with a greater diagnostic efficacy than serum CEA and CA19-9 levels.

[Prognostic Value of PCMT1 Expression in Gastric Cancer and Its Regulatory Effect on Spindle Assembly Checkpoints]

Objective

The study was conducted to investigate the expression of protein-L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) in gastric cancer and its effect on the prognosis, and to analyze its potential mechanism.

Methods

UALCAN, a cancer data analysis platform, was used to conduct online analysis of the expression of PCMT1 in gastric cancer tissues. Through the Database for Annotation, Visualization and Integrated Discovery (DAVID), Gene Ontology (GO) annotation and signaling pathway enrichment by Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to analyze the possible functions and signaling pathways. A total of 120 patients who underwent radical gastrectomy for gastric cancer between January 2014 and December 2017 in our hospital were enrolled for the study. Immunohistochemical staining was performed to determine the expression of PCMT1 and Ki67 in gastric cancer tissues. Cox regression, Kaplan-Meier curve, and receiver operating characteristic (ROC) curves were used for prognostic analysis of 5-year survival in gastric cancer patients after surgery. Lentivirus was used to construct PCMT1-interfering or PCMT1-overexpressing vectors, which were then used to transfect human gastric cancer cell lines of MGC-803 and HGC-27 cells. The interfering empty vector (sh-NC) group, the interfering PCMT1 vector (sh-PCMT1) group, the overexpressing empty vector (LV-Vec) group, and the overexpressing PCMT1 vector (LV-PCMT1) group were set up. Western blot was performed to determine the protein expression levels of PCMT1, CyclinB1, and CDC20. CCK-8 assay was performed to measure the proliferation of gastric cancer cells. Flow cytometry was performed to determine the cell cycle. MGC-803 cells were injected in four groups of nude mice to construct a subcutaneous xenograft tumor model, with three nude mice in each group. The body mass of the nude mice was measured. The nude mice were sacrificed after 14 days and the tumor volume was monitored. The expression levels of CyclinB1 and CDC20 proteins in the tumor tissues were determined by Western blot assay.

Results

Analysis with UALCAN showed that PCMT1 was highly expressed in gastric cancer tissues. Moreover, elevated expression was found in gastric tumor tissues of different pathological stages and grades and those with lymph node metastasis (P<0.05). GO and KEGG enrichment analyses showed that PCMT1 was mainly involved in the signal regulation of mitosis, spindle assembly checkpoints, and cell cycle. The immunohistochemical results showed that PCMT1 and Ki67 were highly expressed in gastric cancer tissues and that they were positively correlated with each other (P<0.05). Cox multivariate analysis showed that high PCMT1 expression (hazard ratio [HR]=2.921, 95% confidence interval [CI]:1.628-5.239) was one of the independent risk factors affecting the 5-year survival rate of gastric cancer patients after surgery. Kaplan-Meier curve showed that patients with high PCMT1 expression had a lower 5-year survival after surgery (16.7%, HR=4.651, 95% CI: 2.846-7.601) than patients with low PCMT1 expression (70.0%, HR=0.215, 95% CI: 0.132-0.351) did. The ROC curve showed that PCMT1 had an area under the curve (AUC) of 0.764 (95% CI: 0.674-0.854) for predicting 5-year patient survival after surgery. Western blot results showed that lentiviral interference or overexpression of PCMT1 cell lines was successfully constructed. The results of CCK-8 showed that the proliferative ability of MGC-803 and HGC-27 cells was weakened with the downregulation of PCMT1, and the overexpression of PCMT1 promoted cell proliferation (P<0.05). With the interference of PCMT1, the expression of CDC20 protein was decreased, the expression of CyclinB1 protein was increased, and the cell cycle was arrested in the G2/M phase. In contrast, the overexpression of PCMT1 led to the opposite trends (P<0.05). In the sh-PCMT1 group, the tumor volume and mass were decreased and the expression of CDC20 protein was decreased and the expression of CyclinB1 protein was increased in the tumor tissues of the nude mice (P<0.05, compared with those of the sh-NC group. In contrast, the LV-PCMT1 group showed the opposite trends (P<0.05, compared with those of the LV-Vec group).

Conclusion

The high expression of PCMT1 in gastric cancer tissues is associated with poor prognosis in patients and may affect tumor cell malignant proliferation via regulating spindle checkpoints in the process of mitosis.

[High expression of RAB7A is associated with poor prognosis of gastric cancer by promoting tumor invasion]

OBJECTIVE

To explore the expression level of Ras-related protein 7A (RAB7A) in gastric cancer and its prognostic implications.

METHODS

Based on data from public databases and a cohort of 104 patients undergoing radical gastrectomy for gastric cancer in our hospital, we analyzed RAB7A expression level in gastric cancer and adjacent tissues and its association with clinicopathological parameters and prognosis of the patients. Bioinformatic analysis was performed to predict the pathways of RAB7A to affect gastric cancer invasion. In gastric cancer MGC803 cells with lentivirus-mediated interference or overexpression of RAB7A, the changes in extracellular matrix (ECM) degradation and cell migration and invasion were analyzed using immunoblotting, wound healing assay and Transwell experiments.

RESULTS

The data from public cancer databases and clinical samples showed a significantly higher expression of RAB7A in gastric cancer tissues than in normal or adjacent tissues (P<0.01) with a close correlation with a poorer patient survival (P<0.01) and a positive correlation with serum carcinoembryonic antigen and carbohydrate antigen 19-9 levels (P<0.001). Univariate and multivariate Cox regression analyses suggested that a high RAB7A expression was an independent risk factor affecting the 5-year survival rate of gastric cancer patients (HR: 2.882; 95% CI: 1.459-5.693). ROC curve analysis showed that at the cut-off value of 2.625, RAB7A expression level had a sensitivity of 84.62% and a specificity of 71.15% for predicting postoperative 5-year mortality of the patients. Bioinformatic analysis suggested that RAB7A was involved in ECM degradation and activation of PI3K/AKT signaling in gastric cancer. MGC803 cells with RAB7A overexpression showed activation of the PI3K/AKT signaling pathway (P<0.01) with enhanced expressions of MMP-2 and MMP-9 (P<0.01) and cell migration and invasion capacities (P<0.01).

CONCLUSION

RAB7A is highly expressed in gastric cancer tissues and affects the patients' prognosis possibly by activating the PI3K/AKT signaling pathway and enhancing ECM degradation to promote tumor invasion.

[High expression of CAMSAP2 promotes invasion and metastasis of gastric cancer cells by upregulating TGF-β signaling]

OBJECTIVE

To investigate the expression of calmodulin-regulated spectrin-associated protein 2 (CAMSAP2) in gastric cancer and its effect on gastric cancer cell invasion and metastasis.

METHODS

The association of CAMSAP2 expression levels with progression and prognosis of gastric cancer was analyzed using public cancer data and in 106 patients receiving radical gastrectomy in our hospital from October, 2013 to October, 2017. The biological functions of CAMSAP2 were predicted using bioinformatics analysis. Gastric cancer MGC803 cells with CAMSAP2 overexpression and knockdown were observed for epithelial-mesenchymal transition (EMT), migration and invasion. A nude mouse model bearing orthotopic gastric cancer cell xenografts was established for verifying the results and exploring the underlying molecular mechanism.

RESULTS

Gastric cancer tissues expressed high levels of CAMSAP2, which were positively correlated with CEA and CA19-9 (P<0.001). Cox regression analysis showed that CAMSAP2 expression level was an independent risk factor affecting the 5-year survival rate of gastric cancer patients (HR=2.969, 95% CI: 1.031-8.548). Enrichment analysis suggested that CAMSAP2 was involved in epithelialmesenchymal transition (EMT) and TGF-β signaling. In gastric cancer cells, CAMSAP2 overexpression significantly increased the expressions of vimentin and N-cadherin, inhibited the expression of E-cadherin, and enhanced cell migration and invasion (P<0.05); CAMSAP2 knockdown produced the opposite effects in the cells (P<0.05). In the tumor- bearing mice, xenografts overexpressing CAMSAP2 showed enhanced metastasis (P<0.05), increased vimentin and N-cadherin expressions and lowered E-cadherin expression (P<0.05), and the xenografts with CAMSAP2 knockdown showed the opposite changes (P<0.05). Both the in vivo and in vitro experiments showed that CAMSAP2 overexpression increased and CAMSAP2 knockdown lowered the levels of TGF-β and p-Smad2/3 in the gastric cancer cells (P<0.05).

CONCLUSION

The high expression of CAMSAP2 contributes to disease progression and poor prognosis of gastric cancer possibly by upregulating TGF-β signaling to promote EMT.

[High expression of MRPL13 promotes cell cycle progression and proliferation of gastric cancer cells by inhibiting p53 signaling to affect long-term prognosis]

OBJECTIVE

To determine the expression of mitochondrial ribosomal protein L13 (MRPL13) in gastric cancer and its impact on long-term prognosis and explore the possible mechanism.

METHODS

We analyzed MRPL13 expression level in gastric cancer and its association with the patients' prognosis based on the public cancer database the data of 100 gastric cancer patients undergoing radical gastrectomy in our hospital from January, 2014 to October, 2017. We further assessed the effects of MRPL13 overexpression and knockdown on proliferation and cell cycle of gastric cancer MGC-803 and SGC-7901 cells in vitro and on subcutaneous xenograft growth in nude mice.

RESULTS

Both bioinformatic analysis and the patients' data demonstrated that the expression level of MRPL13 was significantly higher in gastric cancer than in adjacent tissues (P<0.05) and positively correlated with peripheral blood Ki67, CEA and CA19-9 levels (P<0.05). High expression of MRPL13 was an independent risk factor affecting the 5-year survival rate of gastric cancer patients (HR: 3.284; 95% CI: 1.537-7.016). Gene set enrichment analysis suggested that MRPL13 was involved in cell cycle and p53 signaling. In cultured gastric cancer cells, MRPL13 overexpression significantly promoted cell proliferation, G1/S phase transition and the expressions of cyclin D1 and CDK6 (P<0.05), and MRPL13 knockdown produced the opposite effects (P<0.05). MRPL13 overexpression significantly promoted gastric cancer cell xenograft growth (P<0.05), and MRPL13 knockdown obviously inhibited tumor growth in nude mice (P<0.05). In both cultured gastric cancer cells and the xenografts in nude mice, MRPL13 overexpression significantly decreased while MRPL13 knockdown enhanced the expressions of p53 and p21 (P<0.05).

CONCLUSION

MRPL13 is highly expressed in gastric cancer and affects the long- term prognosis of the patients possibly by inhibiting p53 signaling to promote cancer cell proliferation and cell cycle progression.

[Acetylcorynoline relieves 2, 4, 6-trinitrobenesulfonic acid-induced Crohn's disease-like colitis in mice by regulating intestinal epithelial cell apoptosis]

OBJECTIVE

To explore the effect of acetylcorynoline for relieving 2, 4, 6-trinitrobenzenesulfonic acid (TNBS)-induced Crohn's disease (CD)-like colitis in mice and explore the underlying mechanism.

METHODS

Male C57BL/6 mice were subjected to TNBS treatment to establish models of TNBS-induced CD-like colitis, followed by treatment with saline or 10, 20, or 40 mg/kg acetylcorynoline by gavage. The protective effect of acetylcorynoline against colitis was evaluated by monitoring body weight changes, measurement of DAI and colon length, and histological examination. The colon tissues and cultured colon organoids treated with LPS and acetylcorynoline were examined for expressions of tight junction proteins and apoptosis-related proteins using immunofluorescence assay, Western blotting, and TUNEL staining. The mechanism of acetylcorynoline-induced inhibition of intestinal epithelial cell apoptosis was predicted by network pharmacology and verified by Western blotting.

RESULTS

Acetylcorynoline treatment significantly alleviated weight loss and colon length shortening and reduced DAI score and inflammation score in TNBS mice (P < 0.05). Claudin-1 was significantly upregulated in the colon tissue of acetylcorynolinetreated mice (P < 0.05), where the protein levels of claudin-1, ZO-1, and Bcl-2 were increased and C-caspase3 and Bax were reduced (P < 0.05) and the number of apoptotic intestinal epithelial cells decreased (P < 0.05). In cultured colon organoids, acetylcorynoline significantly increased ZO-1, claudin-1 and Bcl-2 expressions and decreased C-caspase3 and Bax expressions (P < 0.05). KEGG pathway enrichment analysis suggested that the PI3K- AKT signaling pathway was correlated with acetylcorynoline treatment for CD, and the expressions of p-AKT and p-PI3K decreased significantly after the treatment in both the in vivo and in vitro models (P < 0.05). The PI3K-AKT activator (740Y-P) significantly promoted the expressions of p-PI3K, p-AKT, C-caspase3 and Bax and inhibited Bcl-2 in the colon organoids (P < 0.05).

CONCLUSION

Acetylcorynoline protects against TNBS-induced CDlike colitis in mice possibly by suppressing the activation of the PI3K/AKT signaling pathway, thereby inhibiting apoptosis of the intestinal epithelial cells.

[High expression of death-associated protein 5 promotes glucose metabolism in gastric cancer cells and correlates with poor survival outcomes]

OBJECTIVE

To investigate the prognostic value of death-associated protein 5 (DAP5) in gastric cancer (GC) and its regulatory effect on aerobic glycolysis in GC cells.

METHODS

We analyzed DAP5 expression levels in GC and adjacent tissues and its association with survival outcomes of GC patients using public databases. We collected paired samples of GC and adjacent tissues from 102 patients undergoing radical resection of GC in our hospital from June, 2012 to July, 2017, and analyzed the correlation of DAP5 expression level detected immunohistochemically with the clinicopathological parameters of the patients. Cox regression analysis, Kaplan-Meier analysis, and ROC curves were used to explore the independent risk factors and the predictive value of DAP5 expression for 5-year survival of the patients. In the cell experiments, we observed the changes in aerobic glycolysis in MGC-803 cells following lentivirus-mediated DAP5 knockdown or overexpression by measuring glucose uptake and cellular lactate level and using qRT-PCR and Western blotting.

RESULTS

Analysis using the public databases showed that DAP5 was highly expressed in GC and correlated with tumor progression and poor survival outcomes of the patients (P < 0.05). In the clinical samples, DAP5 expression was significantly higher in GC than in the adjacent tissues (3.19±0.60 vs 1.00±0.12; t=36.863, P < 0.01), and a high expression of DAP5 was associated with a reduced 5-year survival rate of the patients (17.6% vs 72.5%; χ2=29.921, P < 0.05). A high DAP5 expression, T3-4, N2-3, and CEA≥5 ng/mL were identified as independent risk factors affecting 5-year survival outcomes of GC (P < 0.05), for which DAP5 expression showed a prediction sensitivity, specificity and accuracy of 73.2%, 80.4% and 79.0%, respectively. In MGC-803 cells, DAP5 knockdown significantly reduced glucose uptake, lactate level and the expressions of GLUT1, HK2 and LDHA, and DAP5 overexpression produced the opposite effects (P < 0.05).

CONCLUSION

A high expression of DAP5 in GC, which enhances cellular aerobic glycolysis to promote cancer progression, is correlated with a poor survival outcome and may serve as a biomarker for evaluating long-term prognosis of GC patients.

[Prognostic Value of the Expression of Myeloid Leukemia Factor 1-Interacting Protein in Gastric Cancer and Its Regulatory Role in Tumor Progression]

Objective

To investigate the prognostic value of the expression of myeloid leukemia factor 1-interacting protein (MLF1IP) in gastric cancer tissue and its regulatory role in tumor progression.

Methods

Gene Expression Omnibus (GEO) database was used to analyze the expression level of MLF1IP in tumor tissues of gastric cancer patients. Kaplan-Meier Plotter database was used to analyze the relationship between MLF1IP expression level and patient prognosis. We conducted a retrospective analysis of 108 gastric cancer patients who had undergone radical surgery at our hospital between January 2015 and December 2015. The expression of MLF1IP in gastric cancer tissue and adjacent tissues was examined. We analyzed the relationship between MLF1IP and the clinicopathological parameters of gastric cancer patients and its impact on the long-term prognosis of gastric cancer patients. Univariate and multivariate regression analyses were done to identify the risk factors affecting the long-term prognosis of gastric cancer patients. The assessment value of MLF1IP for long-term prognosis of gastric cancer was analyzed with ROC curve. The effects of MLF1IP on the proliferation, migration, and invasion of gastric cancer cells were analyzed in vitro with gastric cancer cell line (MGC803). A xenograft tumor model was established with nude mice to analyze in vivo the effect of MLF1IP on tumor growth.

Results

The results of the gastric cancer cohort GSE29272 of GEO database showed that the expression level of MLF1IP in gastric cancer tissues was significantly higher than that in normal tissues ( P<0.05). Analysis with Kaplan-Meier Plotter database indicated that high MLF1IP expression was correlated with poor prognosis in gastric cancer patients. Immunohistochemical analysis showed that the expression level of MLF1IP in gastric cancer tissues was higher than that in adjacent tissues ( P<0.05). Correlation analysis showed that the MLF1IP level in gastric cancer tissue was positively correlated with Ki67 ( r=0.609, P<0.01), peripheral blood carcinoembryonic antigen (CEA) ( r=0.572, P<0.01) and carbohydrate antigen 19-9 (CA19-9) ( r=0.623, P<0.01). Kaplan-Meier (K-M) survival analysis showed that the 5-year survival rate of patients in the MLF1IP high expression group was significantly lower than that in the MLF1IP low expression group ( P<0.01). Cox regression analysis showed that independent risk factors for 5-year survival after radical gastrectomy for gastric cancer included the expression of MLF1IP ( HR=2.508, 95% CI: 1.259-4.999), CEA≥5 μg/L ( HR=2.171, 95% CI: 1.152-4.092), CA19-9≥37 kU/L ( HR=2.401, 95% CI: 1.094-5.269), and T3-T4 stages ( HR=2.779, 95% CI: 1.049-7.358) and N2-N3 stages ( HR=2.072, 95% CI: 1.100-3.904). ROC analysis showed that the sensitivity, specificity, and accuracy of MLF1IP (the cut-off value was 3.00 relative protein expression level) in assessing the 5-year survival rate after radical gastrectomy for gastric cancer was 75.00%, 76.92%, and 76.2%, respectively ( P<0.05). CCK-8, Transwell assay, and scratch assays showed that in vitro knocking down of MLF1 IP gene expression significantly inhibited the proliferation, migration and invasion of gastric cancer cells. Subcutaneous tumor xenograft experiment in nude mice showed that knocking down MLF1 IP gene significantly inhibited tumor growth.

Conclusion

Increased expression of MLF1IP in gastric cancer tissue, which may be involved in the malignant activities of proliferation, migration, and invasion of gastric cancer cells, has a certain predictive value for poor prognosis.