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Bone marrow‐derived mesenchymal stem cells (BM‐MSCs) are important precursors of tumor stromal cells. Previously, we have demonstrated that miR‐155‐5p inhibition directly induced transition of BM‐MSCs into gastric cancer‐associated MSCs. Whether miR‐155‐5p is involved in the education of BM‐MSCs by gastric cancer cells has not been established. Murine BM‐MSCs (mMSCs) were isolated and grown in conditioned medium derived from gastric cancer cell line MFC (MFC‐CM). The tumor‐promoting phenotype and function of mMSCs were detected by immunofluorescence staining, quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR), cell colony formation assay, transwell migration, and invasion assays. Luciferase reporter assays and western blot analyses were conducted to reveal the relationship between nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) p65 and mmu‐miR‐155‐5p. miRNA mimics, inhibitor, and the NF‐κB inhibitor pyrrolidine dithiocarbamic acid (PDTC) were used to evaluate the role of miR‐155‐5p‐NF‐κB signaling in the education of mMSCs by MFC‐CM. We successfully established the education model of mMSCs by MFC‐CM and found that mmu‐miR‐155‐5p expression levels were reduced in mMSCs. Mimicking this deregulation by transfecting miRNA inhibitor into mMSCs produced a similar effect as that of MFC‐CM on mMSCs. NF‐κB p65 was validated as a target of mmu‐miR‐155‐5p, which also negatively regulated NF‐κB activation. Inhibition of NF‐κB activation by PDTC abolished the effect of the miRNA inhibitor on mMSCs. mmu‐miR‐155‐5p overexpression partially blocked the effect of MFC‐CM in educating mMSCs, while PDTC treatment completely eliminated MFC‐CM activity. These results indicate that miR‐155‐5p is not the sole miRNA mediating the education of BM‐MSCs by gastric cancer cells, but downstream NF‐κB signaling is indispensable for this process.

Gastric cancer tissue-derived MSC-like cells (GC-MSC) share similar characteristics to bone marrow MSC (BM-MSC); however, the phenotypical and functional differences and the molecular mechanism of transition between the two cell types remain unclear. Compared to BM-MSC, GC-MSC exhibited the classic phenotype of reactive stroma cells, a stronger gastric cancer promoting capacity and lower expression of miR-155-5p. Inhibition of miR-155-5p by transfecting miRNA inhibitor induced a phenotypical and functional transition of BM-MSC into GC-MSC-like cells, and the reverse experiment deprived GC-MSC of tumor-promoting phenotype and function. NF-kappa B p65 (NF-κB p65) and inhibitor of NF-kappa B kinase subunit epsilon (IKBKE/IKKε) were identified as targets of miR-155-5p and important for miRNA inhibitor activating NF-κB p65 in the transition. Inactivation of NF-κB by pyrrolidine dithiocarbamic acid (PDTC) significantly blocked the effect of miR-155-5p inhibitor on BM-MSC. IKBKE, NF-κB p65 and phospho-NF-κB p65 proteins were highly enriched in MSC-like cells of gastric cancer tissues, and the latter two were correlated with the pathological progression of gastric cancer. In GC-MSC, the expression of miR-155-5p was downregulated and NF-κB p65 protein was increased and activated. NF-κB inactivation by PDTC or knockdown of its downstream cytokines reversed the phenotype and function of GC-MSC. Taken together, our findings revealed that miR-155-5p downregulation induces BM-MSC to acquire a GC-MSC-like phenotype and function depending on NF-κB p65 activation, which suggests a novel mechanism underlying the cancer associated MSC remodeling in the tumor microenvironment and offers an effective target and approach for gastric cancer therapy.

Chronic inflammation has a decisive role in tumorigenesis, particularly in gastric carcinogenesis. The CC chemokine ligand 2 (CCL2), an important inflammatory cytokine, is involved in the initiation, development and progression of various types of cancer. However, the role of CCL2 in gastric cancer remains to be elucidated. The present study demonstrated that recombinant CCL2 stimulation caused no effect on the morphology, proliferation and migration of human GES-1 gastric mucosa epithelial cells, in which the protein expression of CC-chemokine receptor 2 (CCR2) was markedly low. However, the expression of CCR2 was significantly upregulated in the GES-1 cells following pretreatment with the chemical carcinogen, N-methyl-N-nitro-N'-nitrosoguanidine (MNNG), for 12 h or transformed with MNNG (MC cells). The present study used CCL2 to stimulate MNNG pretreated GES-1 cells and MC cells, and demonstrated that CCL2 clearly promoted their migration and the epithelial-mesenchymal transition (EMT). However, no effect was observed on the proliferative ability of the cells. Taken together, these findings suggested that the CCL2/CCR2 chemokine signaling may regulate the EMT in gastric epithelial cells and resulted in gastric carcinogenesis in response to the intake of the carcinogen, MNNG.

Long noncoding RNAs have been reported to be essential regulators in several human diseases, including tumorigenesis. A recent report revealed that FLVCR1-AS1 promotes the progression of hepatocellular carcinoma. However, whether FLVCR1-AS1 is involved in lung cancer remains unclear. In this study, we found that the expression of FLVCR1-AS1 was increased in lung cancer tissues according to The Cancer Genome Atlas database. Similarly, FLVCR1-AS1 was significantly upregulated in lung cancer cell lines. Knockdown of FLVCR1-AS1 dramatically reduced the cell proliferation, migration, and invasion of SPCA1 and A549. Mechanistically, we found that the expression levels of CTNNB1, SOX4, CCND1, CCND2, c-MYC, as well as nucleus β-catenin were decreased in lung cancer cells after FLVCR1-AS1 silencing. Thus, FLVCR1-AS1 positively regulates the activation of the Wnt/β-catenin pathway. Overexpression of CTNNB1 reversed the effect of FLVCR1-AS1 knockdown on A549 cells. In sum, FLVCR1-AS1 silencing inhibited the proliferation, migration, and invasion of lung cancer cells by inhibiting the activity of the Wnt/β-catenin signaling pathway.

Injury of hippocampal neurons in status epilepticus (SE) SD rats kindled by pentylenetetrazol (PTZ) were studied, and the changes of apoptosis neurons, protein expression of Bad and Bcl-2 alone and combined application of phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002 and recombinant human erythropoietin (rHuEpo) were evaluated for the possible mechanisms of rHuEpo. The SE rats kindled by the PTZ were randomly divided into normal control group [normal saline (NS)], model group (PTZ + NS), rHuEpo treated group (PTZ + rHuEpo), LY294002 treated group (PTZ + LY294002 + rHuEpo) and LY294002 control group (rHuEpo + PTZ + DMSO). Apoptosis of hippocampal neurons was detected by TUNEL method; expression of phosphorylation protein kinase B (p-PKB/p-Akt), Bcl-2 and Bad were detected by immunohistochemistry; the expression of Bcl-2 mRNA, Bad mRNA in hippocampal neurons of rats were detected through reverse transcription polymerase chain reaction (RT-PCR); the expression of Akt, p-Akt and Bcl-2, Bad protein in hippocampal neurons of rats were detected by western blotting. The amount of apoptotic neurons was less in the rHuEpo treated group and the LY294002 control group than in the LY294002 treated group (P

The inflammatory microenvironment contributes to cancer development and progression. Mesenchymal stem cells (MSCs), as important stromal cells, may be 'educated' by the inflammatory microenvironment to support the development of gastric cancer. Cytokines are a key component of cancer-related inflammation. Interleukin (IL)-6, as an inflammatory cytokine, has multiple roles in cancer. However, whether MSCs can be 'educated' by IL-6 to support gastric cancer remains unknown. In the present study, we focused on the phenotype and function of human umbilical cord-derived MSCs hUC‑MSCs pre-treated with IL-6 in gastric cancer. We found that the protein levels of α-smooth muscle actin (α-SMA) were upregulated, and phosphorylated nuclear factor (NF)-κB protein levels were downregulated in the hUC‑MSCs pre-treated with IL-6, as shown by western blot analysis. The levels of tumor‑promoting cytokines, including chemokine (C-C motif) ligand 5 (CCL5), platelet-derived growth factor‑BB (PDGF‑BB), monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor α(TNFα), were markedly reduced in the hUC‑MSCs following treatment with IL-6, as shown by RT-qPCR. In in vitro experiments, we co-cultured MSCs with N-methyl‑N'‑nitro‑N‑nitrosoguanidine (MNNG)‑transformed GES-1 gastric epithelial cells or SGC-7901 gastric cancer cells. Transwell and colony-forming cell assays revealed that the hUC-MSCs significantly promoted gastric cellular migration and proliferation. However, following treatment with IL-6, the hUC-MSCs had no growth-promoting effect on the gastric epithelial cells and gastric cancer cells. In in vivo experiments, we co-transplanted MSCs and SGC-7901 cells into nude mice in order to establish a nude mouse model of gastric cancer. The hUC-MSCs significantly promoted the growth gastric tumors through the promotion of cell proliferation and the inhibition of cell apoptosis. On the contrary, pre-treatment with IL-6 provided the hUC‑MSCs with the ability to inhibit cell proliferation and significantly induce cell apoptosis. Taken together, our findings indicate that pre-treatment with IL-6 significantly abolishes the ability of hUC-MSCs to promote gastric epithelial cell proliferation and migration and provide new insight into the effects of the inflammatory cytokine, IL-6, on the tumor-promoting ability of MSCs and its role in gastric cancer.

In some refineries, storage tanks are located at two different sites, one for low-fusion-point crude oil and the other for high one. Two pipelines are used to transport different oil types. Due to the constraints resulting from the high-fusion-point oil transportation, it is challenging to schedule such a system. This work studies the scheduling problem from a control-theoretic perspective. It proposes to use a hybrid Petri net method to model the system. It then finds the schedulability conditions by analysing the dynamic behaviour of the net model. Next, it proposes an efficient scheduling method to minimize the cost of high-fusion-point oil transportation. Finally, it gives a complex industrial case study to show its application.