The renin-angiotensin system blockers and survival in digestive system malignancies: A systematic review and meta-analysis.

BACKGROUND: Accumulating pre-clinical and clinical studies suggested that the renin-angiotensin system blockers (RASBs) possess anti-carcinogenic properties, and their use is associated with favorable outcomes in many types of cancers. METHODS: A systematic literature search of relevant databases through January 2019 was conducted to identify studies assessing the RASBs on prognostic outcomes in digestive system malignancies patients on the basis of predetermined selection criteria for pooled hazard ratio (HR) with 95% confidence intervals (CIs). A total of 13 studies were included in the meta-analysis. RESULTS: The meta-analysis showed that the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) resulted in a significant improvement in overall survival (HR 0.79; 95%CI 0.70-0.89; P < .000), cancer-specific survival (HR 0.81; 95%CI 0.73-0.90; P < .000) and recurrence-free survival (HR 0.68; 95%CI 0.54-0.85; P = .001), but not progression-free survival (HR 0.88; 95%CI 0.73-1.07; P = .183) and disease-free survival (HR 0.50; 95%CI 0.11-2.39; P = .103). Subgroup analysis indicated that the use of RASBs has a significant improvement of overall survival (OS) in pancreatic cancer, liver cancer, and gastric cancer. Two studies evaluated the dose-response relationship between ACEIs/ARBs therapy and survival and showed higher doses and better survival [(1-364 defined daily doses: odds ratio (OR) 0.89, 95%CI 0.78-1.01, P = .076), (≥365 defined daily doses: OR 0.54, 95%CI: 0.24-1.24, P = .148]. CONCLUSIONS: Meta-analysis of studies supports a beneficial association between use of RASBs and survival of digestive system malignancies.

DNA-methylation-mediated silencing of miR-7-5p promotes gastric cancer stem cell invasion via increasing Smo and Hes1.

Cancer stem cells are undifferentiated cancer cells that have self-renewal ability, a high tumorigenic activity, and a multilineage differentiation potential. MicroRNAs play a critical role in regulating gene expression during carcinogenesis. Here, we investigated the role of miR-7 and the mechanism by which it is dysregulated in gastric cancer stem cells (GCSCs). The stem cell marker, CD44, was used to sort GCSCs by fluorescence-activated cell sorting. We found that CD44 (+) cells have higher invasiveness and form more number of sphere colonies than CD44 (-) cells. Quantitative real-time polymerase chain reaction (PCR) revealed that the miR-7-5p expression was remarkably downregulated in GCSCs but was significantly increased in the methionine-deprived medium. The downregulation of miR-7-5p results from the increased DNA methylation in the promoter region using the methylation-specific PCR. Overexpression of miR-7-5p reduced the formation of colony and decreased the invasion of GCSCs through targeting Smo and Hes1 and subsequent repressing Notch and Hedgehog signaling pathways in vitro. Notably, upregulating miR-7-5p inhibited the growth of tumor in the xenograft model. Hence, these data demonstrated that miR-7-5p represses GCSC invasion through inhibition of Smo and Hes1, which provides a potential therapeutic target of gastric cancer treatment.

METase promotes cell autophagy via promoting SNHG5 and suppressing miR-20a in gastric cancer.

BACKGROUND: Gastric cancer (GC) severely threatens human life, and METase seemed to inhibit tumor growth. However, the potential mechanism underlying it is still unclear. METHODS: Both clinical tissues and cell lines were used in the present study. SNHG5 and miR-20a expressions were determined using real-time PCR. Western blot was performed to determine the expression of autophagy-related proteins. The interaction between miR-20a and SNHG5 was determined using luciferase reporter assay and RNA immunoprecipitation (RIP). RESULTS: The expression of SNHG5 was decreased in GC tissues and cell lines. Overexpressed METase significantly promoted cell apoptosis and autophagy, as well as the expression of SNHG5. SNHG5 directly regulated the expression of miR-20a. GC cells transfected with pcDNA-SNHG5 significantly promoted cell apoptosis and autophagy, while the co-transfected with miR-20a mimic dramatically reversed the effects of pcDNA-SNHG5. Overexpressed METase significantly promoted cell autophagy, which was abolished by down-regulated SNHG5. CONCLUSION: Overexpressed METase promoted cell apoptosis and autophagy via up-regulating the expression of SNHG5 and down-regulating miR-20a in GC.

Hyaluronic acid-modified polyamidoamine dendrimer G5-entrapped gold nanoparticles delivering METase gene inhibits gastric tumor growth via targeting CD44+ gastric cancer cells.

BACKGROUND: Gastric cancer (GC) is the second most common leading cause of cancer-related death. Cancer stem cell (CSC) with the mark of CD44 played an important role in GC. rMETase was wildly exploited as chemotherapeutic option for GC. Polymers synthetic nanoparticle drug delivery systems have been commonly used for cancer therapy. With the decorating of Hyaluronic acid (HA), a receptor of CD44, nanoparticles exhibit with good biocompatibility and aqueous solubility. METHODS: The characteristic of nanoparticles (NPs) was analyzed by TEM and DLS. The viability and proliferation of GC cells were examined by MTT assays. The levels of CD44, Cyt C, and c-caspase 3 were examined by Western blot. The level of ROS was measured by DCFH-DA assays. The morphology of tissues was detected using hematoxylin-eosin (H&E) stain. Nude mice xenograft models were used to evaluate the effect of HA-PAMAM-Au-METase on GC. RESULTS: The transfection of rMETase carried by HA-G5 PAMAM-Au visibly inhibited the proliferation and tumorsphere formation of GC cells through obviously enhancing METase activity. Elevation of METase activity suppressed the proliferation of CD44(+) GC cells through down-regulating MET in cellular supernatant that resulted in the increase of Cyc C and ROS levels. The number of CD44(+) GC cells in nude mice injected with G5 PAMAM-Au-METase decorated by HA was markly declined resulting in the inhibition of tumor growth. CONCLUSION: HA-G5 PAMAM-Au-METase significantly suppressed tumor growth of GC by targeted damaging the mitochondrial function of CD44(+) gastric CSCs.

The mechanism study of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin.

BACKGROUND: To investigate the mechanism of lentiviral vector carrying methioninase enhances the sensitivity of drug-resistant gastric cancer cells to Cisplatin. METHODS: Death receptors, anti-apoptotic protein, NF-κB, and TRAIL pathway-related factors were detected. The influence of LV-METase transfection on cell viability and pathway-related proteins were assessed by MTT method and western blot, respectively. Different treatments (NF-κB or caspase-3 inhibitor induction, TRAIL supplement, etc.) were performed in gastric cancer cells and the above parameters were analysed. Moreover, the connection between miR-21 and NF-κB or caspase-8 was determined by Chip and luciferase assay, respectively. LV-METase transfection drug-resistant gastric cancer cells were injected subcutaneously into mice. RESULTS: The expression of free MET, miR-21-5p, MDR1, P-gp, and DR5 was significantly increased in drug-resistant gastric cancer cell lines. When cells were transfected with LV-METase, intracellular TRAIL signalling was activated while NF-κB pathway was inhibited. Besides, enhanced TRAIL signalling or repressed NF-κB pathway can promote the sensitivity of drug-resistant strains to Cisplatin, and the combination shows more sensitive to sensitisation. LV-METase promoted TRAIL expression by reducing NF-κB, thereby contributing to the downregulation of P-gp and enhancing the susceptibility of drug-resistant gastric cancer cells to Cisplatin. Furthermore, miR-21 regulated by NF-κB mediated the expression of P-gp protein via inhibiting caspase-8, thus regulating Cisplatin-induced cell death. CONCLUSIONS: Our results suggest that LV-METase has potential as a therapeutic agent for gastric cancer treatment.

Evaluation of METase-pemetrexed-loaded PEG-PLGA nanoparticles modified with anti-CD133-scFV for treatment of gastric carcinoma.

PEG-PLGA nanoparticles (NPs) modified with anti-CD133 and tumor-targeting single-chain antibody fragment (scFV-NPs) for systemic delivery of methioninase (METase) and pemetrexed for gastric carcinoma were successfully formulated. The structure characterization and biological functions of METase-pemetrexed-loaded scFV-PEG-PLGA NPs (scFV-METase/pemetrexed-NPs) in vitro were investigated. Functional scFV-PEG-PLGA NPs or PEG-PLGA NPs present low cell cytoxicity in CD133+ SGC7901 cells. scFV-METase/pemetrexed-NPs (scFv-M/P-NP) was more effective in inhibiting tumor growth (including cell growth and migration ability) in CD133 positive expressed gastric cancer cells than METase/pemetrexed-NPs (M/P-NP). Moreover, METase enhanced the inhibitory effect of pemetrexed on thymidylate synthase (TS) synthesis and cell apoptosis. We have demonstrated the application of scFV-targeted PEG-PLGA NPs as a new potential strategy to enhance treatment benefits for gastric carcinoma.

Using a Novel CD133+ Immune Magnetic Particle to Separate Gastric Adenocarcinoma Stem Cells from Peripheral Blood and the Pluripotency Study About the Separated Cells.

Background: Stem cells isolated from peripheral blood of gastric adenocarcinoma patients have noninvasive advantages. However, at present, there is no simple and effective separation technique. Purpose: In this study, CD133+ cells were isolated from peripheral blood of patients with gastric adenocarcinoma by using specific immunomagnetic particles, and the immunology of subcultured cells was identified to evaluate whether the immune magnetic particle separation had any effect on the cells themselves. Methods: Immune magnetic particles, made by a specific technique, are used to sort out the cells whose membrane could express CD133 from peripheral blood of gastric adenocarcinoma patients. By observing the sorted cells within serum-free culturing, we compare the differences in morphology and proliferation ability between the collected cells and cells from a standard tumor cell line. At the same time, an immunofluorescence method is used to detect the expression of the CD133 antibody. Moreover, this study explores the inhibition effect on gastric adenocarcinoma stem cell growth when combining 5-fluorouracil and methionine enzymes. Results and Conclusions: The specific immunomagnetic particles have a small diameter and strong sorting characteristics. In the experiment, there were 20 patients with gastric adenocarcinoma. CD133+ cells were separated successfully from peripheral blood of 13 patients (65%), among which subcultured cells of 9 cases (69.2%) were found to express CD44+ antigens. The sorted cells grew vigorously with a variety of morphologies in non-inducing culture, while the cells induced by ß transforming growth factor presented slow growth and uniform morphology. There was a significant difference (P < 0.05) in cell proliferation between these two groups and the standard tumor cell line. In addition, 5-fluorouracil combined with methionine enzyme inhibited the growth of gastric adenocarcinoma stem cells significantly (P < 0.05). Accordingly, the CD133+/CD44+ cells from peripheral blood of gastric adenocarcinoma patients, sorted by specific immune magnetic particles, had clear stem cell properties as determined by cell function and structure. This lays a foundation for gastric adenocarcinoma stem cell extraction, culture and further research on stem cell characteristics.