Research on Function of Exosome of miR-328-3p Secreted by Bone Marrow Mesenchymal Stem Cells (BMSCs) on Restraining the Gastric Cancer Through Being Down-Regulated with Trefoil Factor 3

Certain progress has been made in the therapeutic method against gastric cancer such as surgical operation combined with chemotherapy and radiation therapy in recent years. But the therapeutic efficacy and prognosis on gastric cancer was still not satisfactory. The function of exosome of miR-328–3p secreted by bone marrow stromal cells (BMSCs) on restraining the gastric cancer was studied in the present study. The BMSCs with highly-expressed miR-328-3p was established. The exosome in cell supernatant was collected. The exosome of BMSCs and MSCs with highlyexpressed miR-328-3p was added into SGC-7901 cells followed by analysis of miR-328-3p level by Real-time PCR and TFF3 (Trefoil Factor 3) level in exosome by Western blot, cell proliferation, expression of E-cadherin, Vimentin and Caspase-3. miR-328-39 expression was reduced and TFF3 was elevated in gastric cancer tissue (P < 0.05). miR-328-3p was upregulated and TFF3 was downregulated after addition of BMSCs exosomes along with increased cell proliferation and reduced E-cadherin and Caspase3 expression (P < 0.05). In conclusion, exosome of BMSCs could be regulated by miR-328-3p and TFF3 expression is restrained so as to regulate the biological behaviors of gastric cancer cell.

Exosomal miRNA-455 from Bone Marrow Stromal Cells (BMSCs) Promotes Macrophage Phagocytosis and Restrains Progression of Gastric Cancer (GC)

Multiple miRNAs are differentially expressed in gastric cancer (GC). Herein, this study aims to investigate miR-455’s role in GC and its mechanism. Exosomes (exo) separated from BMSCs after transfection were co-cultured with either phagocytes, GC cells (NCI-N87 cell), or macrophages combined with NCI-N87cells (mixed group) followed by analysis of the expression of PTEN, N-cadherin, E-cadherin, and PI3K, and AKT by RT-qPCR and Western blot. Increased miR-455 expression was observed in GC cells upon transfection. GC cells in the mixed group relative to NCI-N87 group exhibited a lower cell migration and invasion and impaired proliferative capacity (p < 0.05), accompanied with higher expressions of N-cadherin, E-cadherin, PI3K, and AKT, and decreased level of PTEN (p < 0.05). The combined treatment resulted in a higher phagocytic rate (12.38±0.21%) and phagocytic index (14.29±2.11%) compared to treatment with only phagocytes (p < 0.05). In conclusion, BMSC-derived exosomal miR-455 inhibits the growth of GC cells and promotes the phagocytosis through inactivating PI3K/AKT signaling pathway.

Effect of miR-206 Derived from Bone Marrow Mesenchymal Stem Cells (BMSCs) on CD8 Expression in Gastric Cancer

The BMSCs are one of the components of tumor micro-environment and participate in tumor evolution. Our study aimed to discuss the effect of exosome derived from BMSC on gastric cancer cells. Tumor and para-tumor tissues were isolated to measure miR-206 level by RT-PCR. Gastric cancer cell behaviors were analyzed using MTT assay and scratch test. Gastric cancer model was established and treated TIGIT inhibitor to assess its role in the tumor growth in vivo. The miR-206 in exosome from BMSCs in cancer tissue was detected. CD8 expression excreted by DC could be induced after miR-206 treatment possibly through regulating the signaling pathway of TIGIT/PVR. Inhibition of TIGIT decreased tumor growth, development and reversed tumor phenotype. In conclusion, miR-206 derived from BMSCs induces CD8 expression in gastric cancer through regulating the signaling pathway of TIGIT/PVR, indicating that it might be a novel target for the treatment of gastric cancer.

Stromal Cell-Derived Factor-1α (SDF-1α) Promotes Growth and Migration of Bone Marrow Stromal Cells (BMSCs) and Gastric Cancer Cells Through Phosphatidylinositol 3-Kinase/AKT (PI3K/Akt) Pathway

SDF-1α activity is closely related to information transmission and cell migration when contributing to lymphatic metastasis in various tumors. Herein, we explored the interaction among SDF-1α, CXCR4 and PI3K/Akt signaling pathway in gastric cancer (GC) and their roles in this disorder. Human GC cells KATO-III and BMSCs were co-cultured without contact. GC cells were transfected with SDF-1α, CXCR4 inhibitor, and PI3K inhibitor. After examining the efficiency of transfection, cell migration was evaluated using Transwell chamber, and expression SDF-1α, CD133, and CXCR4 was determined by RT-qPCR. With transfection rate of 98%, the number of migrated cells reduced upon inhibition of CXCR4 and PI3K. Luciferase activity in 565 nm are high than CXCR4 inhibition group. (p < 0.05). Likewise, up-regulation of SDF-1α increased the expression of SDF-1 (0.825±0.061), CD133 (0.875±0.058), CXCR4 (0.801±0.052), and Akt (0.852±0.062), compared to the blank group, CXCR4 inhibition group and PI3K inhibition group (p < 0.05). Down-regulation of CXCR4 and PI3K, however, decreased the expression insignificantly (p > 0.05). Collectively, up-regulation of SDF-1α activates CXCR4 signaling pathway of BMSCs and stimulates its downstream PI3K/Akt signaling pathway and and increases the expression of CD133, thereby promoting malignant behaviors of GC cells.

Bone Marrow Mesenchymal Stem Cell (BMSC)-Derived Exosomal miR-168-5p Inhibits Proliferation and Chemotherapy Resistance in Gastric Cancer by Downregulation of Cyclin D1 and P Glycoprotein

miR-168-5p is indicated as an upstream effector of the tumor suppressor signal pathway in ovarian cancer and bladder cancer, but the role in gastric cancer (GC) remains unknown. This study aims to reveal the expression and significance of miR-168-5p in GC. RT-qPCR analysis was used to detect the expression of miR-168-5p in GC tissues and plasma, and the relationship of miR-168-5p and CCND1 was evaluated. GC cells were co-cultured with BMSCs or transfected with miR-168-5p mimic. CCK-8 assay and flow cytometry were conducted to assess the effect of miR-168-5p in GC and the interaction between BMSCs and cancer cell progression. Animal experiment was established to explore the in vivo effect of miR-168-5p. miR-168-5p is poorly expressed in gastric cancer cells and the plasma of patients with gastric cancer. BMSC co-culture is similar to miR-168-5p mimic induced miR-168-5p expression increase. miR-168-5p overexpression decreased the proliferative, invasive and migratory capacities of GC cells, and promoted apoptosis. Mechanically, miR-168-5p targeted and decreased the expression of CCND1. Additionally, the low miR-168-5p expression in GC was closely related to poor prognosis and malignant transformation. BMSC exosomes carrying miR-168-5p suppress cell progression in GC when inhibiting the expression of CCND1 and P glycoprotein, which indicates potential diagnostic and prognostic value of miR-168-5p and helps the development of miR-168-5p-based treatment for drug-resistant GC.