巨噬细胞移动抑制因子促进新生微血管生成

目的观察巨噬细胞移动抑制因子对体外培养的人血管内皮细胞增殖的作用,以及通过体内外血管生成实验证实巨噬细胞移动抑制因子促进新生微血管生成的作用。方法采用体外培养的人血管内皮细胞株EA-hy926为实验对象,通过四甲基偶氮唑盐比色法测定血管内皮细胞增殖;利用体外血管生成分析试剂盒量化分析巨噬细胞移动抑制因子在体外对新生微血管生成的作用;利用免疫组织化学染色法检测巨噬细胞移动抑制因子作用后基底膜类似物栓子中第Ⅷ因子相关抗原观察巨噬细胞移动抑制因子在小鼠体内对新生微血管生成的作用。结果巨噬细胞移动抑制因子可以促进体外培养的人血管内皮细胞增殖,促进体外培养的人血管内皮细胞在体外形成血管腔,在小鼠体内也能促进基底膜类似物栓子中新生微血管生成。结论巨噬细胞移动抑制因子有促进新生微血管生成的作用。     

环氧合酶2抑制剂的抗胰腺癌作用及相关机制

目的探讨环氧合酶2(COX-2)抑制剂对胰腺癌细胞增殖、侵袭、迁移能力和对COX-2、基质金属蛋白酶(MMP)-14蛋白表达的影响以及可能的抗胰腺癌机制。方法不同浓度的COX-2抑制剂塞来昔布(20、60、100μmol/L)处理胰腺癌细胞后,用MTT比色法检测细胞的增殖能力;用Transwell侵袭实验和划痕实验检测细胞的侵袭能力和迁移能力;ELISA检测MMP-14和COX-2的蛋白表达情况。结果 MTT增殖实验、Transwell侵袭实验、划痕实验分别提示,COX-2抑制剂作用后胰腺癌细胞的增殖、侵袭、迁移能力均以浓度梯度形式下降(P0.05);ELISA结果显示,胰腺癌细胞中COX-2和MMP-14的蛋白表达水平相应降低(P0.05),两者表达具有显著正相关性(r=0.873,P0.05)。结论 COX-2抑制剂可能通过抑制COX-2表达下调MMP-14表达,进而以浓度梯度形式减弱胰腺癌细胞的增殖、侵袭、迁移能力,起到抗胰腺癌作用。     

Receptor protein tyrosine phosphatase beta/zeta is a functional binding partner for vascular endothelial growth factor

Background

Receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) is a chondroitin sulphate (CS) transmembrane protein tyrosine phosphatase and is a receptor for pleiotrophin (PTN). RPTPβ/ζ interacts with α_νβ₃ on the cell surface and upon binding of PTN leads to c-Src dephosphorylation at Tyr530, β₃ Tyr773 phosphorylation, cell surface nucleolin (NCL) localization and stimulation of cell migration. c-Src-mediated β₃ Tyr773 phosphorylation is also observed after vascular endothelial growth factor 165 (VEGF₁₆₅) stimulation of endothelial cells and is essential for VEGF receptor type 2 (VEGFR2) - α_νβ₃ integrin association and subsequent signaling. In the present work, we studied whether RPTPβ/ζ mediates angiogenic actions of VEGF.

Methods

Human umbilical vein endothelial, human glioma U87MG and stably transfected Chinese hamster ovary cells expressing different β₃ subunits were used. Protein-protein interactions were studied by a combination of immunoprecipitation/Western blot, immunofluorescence and proximity ligation assays, properly quantified as needed. RPTPβ/ζ expression was down-regulated using small interference RNA technology. Migration assays were performed in 24-well microchemotaxis chambers, using uncoated polycarbonate membranes with 8 μm pores.

Results

RPTPβ/ζ mediates VEGF₁₆₅-induced c-Src-dependent β₃ Tyr773 phosphorylation, which is required for VEGFR2-α_νβ₃ interaction and the downstream activation of phosphatidylinositol 3-kinase (PI3K) and cell surface NCL localization. RPTPβ/ζ directly interacts with VEGF₁₆₅, and this interaction is not affected by bevacizumab, while it is interrupted by both CS-E and PTN. Down-regulation of RPTPβ/ζ by siRNA or administration of exogenous CS-E abolishes VEGF₁₆₅-induced endothelial cell migration, while PTN inhibits the migratory effect of VEGF₁₆₅ to the levels of its own effect.

Conclusions

These data identify RPTPβ/ζ as a cell membrane binding partner for VEGF that regulates angiogenic functions of endothelial cells and suggest that it warrants further validation as a potential target for development of additive or alternative anti-VEGF therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0287-3) contains supplementary material, which is available to authorized users.     

Gastric cancer-derived mesenchymal stem cells prompt gastric cancer progression through secretion of interleukin-8

Background

Bone marrow mesenchymal stem cells (BM-MSCs) have been identified to be closely associated with tumor growth and progression. However, the roles of tumor-resident MSCs in cancer have not been thoroughly clarified. This study was to investigate the regulating effect of gastric cancer-derived MSCs (GC-MSCs) on gastric cancer and elucidate the underlying mechanism.

Methods

GC-MSCs were isolated from primary human gastric cancer tissues and characterized. The effect of GC-MSCs on gastric cancer cell proliferation was analyzed by MTT assay and colony formation assay. Transwell migration assay was performed to evaluate the influence of GC-MSCs in gastric cancer cell migration. The regulating effects of interactions between gastric cancer cells and GC-MSCs on their pro-angiogenic abilities were analyzed in a co-culture system, with the expression, and secretion of pro-angiogenic factors detected by RT-PCR and Luminex assay. Tube formation assay was used to further validate the angiogenic capability of gastric cancer cells or GC-MSCs. Cytokine profiles in the supernatant of GC-MSCs were screened by Luminex assay and neutralizing antibody was used to identify the key effective cytokines. The activations of Akt and Erk1/2 in gastric caner cells were detected by Western blot.

Results

GC-MSC treatment enhanced the proliferation and migration of BGC-823 and MKN-28 cells, which was more potently than MSCs from adjacent non-cancerous tissues (GCN-MSCs) or bone marrow (BM-MSCs). Higher expression levels of pro-angiogenic factors were detected in GC-MSCs than GCN-MSCs or BM-MSCs. After 10 % GC-MSC-CM treatment, BGC-823, and MKN-28 cells expressed increased levels of pro-angiogenic factors and facilitated tube formation more potently than cancer cells alone. Furthermore, GC-MSCs produced an extremely higher level of interleukin-8 (IL-8) than GCN-MSCs or BM-MSCs. Blockade of IL-8 by neutralizing antibody significantly attenuated the tumor-promoting effect of GC-MSCs. In addition, 10 % CM of IL-8-secreted GC-MSCs induced the activations of Akt or Erk1/2 pathway in BGC-823 and MKN-28 cells.

Conclusion

Tumor-resident GC-MSCs promote gastric cancer growth and progression more efficiently than GCN-MSCs or BM-MSCs through a considerable secretion of IL-8, which could be a possible target for gastric cancer therapy.     

The RNA m6A methyltransferase METTL3 promotes pancreatic cancer cell proliferation and invasion

Epigenetic modifications are involved in carcinogenesis and METTL3 is involved in RNA methylation. This study aimed to explore the role of the RNA m6A methyltransferase METTL3 in pancreatic cancer cells. The m6A modification was analyzed in human pancreatic cancer and paracancerous specimens, as well as in the normal HPDE6-C7 pancreatic cell line and the MIA-PaCa-2 and BxPC-3 pancreatic cancer cell lines. Immunohistochemistry (IHC), western blotting, and RT-qPCR were used to detect the expression of METTL3. Cell lines were transfected with siRNAs against METLL3. Proliferation, invasion, and migration were examined. The functions of METTL3 were predicted by bioinformatics analysis. In the 40 patients included, high METTL3 expression was associated with high pathological stage (P = 0.02) and high N stage (P = 0.02). Survival was better in patients with low METTL3 expression compared with those with high MTTL3 expression (P < 0.01). METTL3 and CIITA expression levels were inversely correlated (r = ?0.71, P < 0.01). RNA m6A content in tumor specimens was significantly higher than that in paracancerous specimens. METTL3 protein and mRNA levels were significantly higher in tumor specimens compared with paracancerous specimens, as well as in cancerous cell lines vs. normal cells. METTL3 knockdown in MIA PaCa-2 and BxPC-3 cells decreased RNA m6A modifications. Cell proliferation, invasion, and migration were decreased by METTL3 knockdown in cancerous cell lines. A total of 673 differentially expressed genes were identified by bioinformatics: 659 were upregulated and 14 were downregulated. In conclusion, METTL3 is probably involved in pancreatic carcinogenesis. It could eventually be a prognostic marker or a treatment target.     

Long Noncoding RNA UCA1 Targets miR-122 to Promote Proliferation,Migration, and Invasion of Glioma Cells

Glioma is the most common and lethal malignant intracranial tumor. Long noncoding RNAs (lncRNAs) have been identified as pivotal regulators in the tumorigenesis of glioma. However, the role of lncRNA urothelial carcinoma-associated 1 (UCA1) in glioma genesis is still unknown. The purpose of this study was to investigate the underlying function of UCA1 on glioma genesis. The results demonstrated that UCA1 was upregulated in glioma tissue and indicated a poor prognosis. UCA1 knockdown induced by si-UCA1 significantly suppressed the proliferative, migrative, and invasive activities of glioma cell lines (U87 and U251). Bioinformatics analysis and luciferase reporter assay verified the complementary binding within UCA1 and miR-122 at the 3¢-UTR. Functional experiments revealed that UCA1 acted as an miR-122 “sponge” to modulate glioma cell proliferation, migration, and invasion via downregulation of miR-122. Overall, the present study demonstrated that lncRNA UCA1 acts as an endogenous sponge of miR-122 to promote glioma cell proliferation, migration, and invasion, which provides a novel insight and therapeutic target in the tumorigenesis of glioma.     

Overexpression of IL-8 promotes cell migration via PI3K-Akt signaling pathway and EMT in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a type of malignant and heterogeneous tumor in premenopausal females with ineffective therapeutic targets. IL-8 is one of the earliest discovered chemotaxis cytokines which expression is closely related to the progress of various cancers. Previous studies showed that IL-8 determines the prognosis of TNBC patients, nevertheless how IL-8 influences the progress of TNBC is unclear. In our studies, we discovered that overexpression of IL-8 promotes TNBC cells (TNBCs) migration and tumor growth via the PI3K-Akt and MAPK signaling pathway. Cell-cycle of TNBCs arrest at S phase by overexpression of IL-8, however, there is no significant variation on the cell viability and cell apoptosis of TNBCs. Besides, overexpression of IL-8 result in the downregulation of E-cadherin and the upregulation of Cyclin B1 in MDA-MB-231 cells. Taken together, our results suggest that IL-8 performs a crucial role in the progress of TNBC, and it could be a novel therapeutic target of TNBC.     

MicroRNA-107抑制喉癌细胞的迁移及侵袭能力的临床分析

目的通过观察microRNA 107（miR 107）在喉癌及癌旁组织中的表达，并且在喉癌细胞系选择性上调及敲减miR 107，检测其对喉癌细胞迁移及侵袭能力的影响。方法收集40例喉癌及其邻近癌旁组织标本，运用RT qPCR检测miR 107的表达，并分析其在喉癌中的临床意义。在人喉癌细胞TU212及TU686中过表达或敲减miR 107，通过Transwell法检测其对喉癌细胞迁移及侵袭能力的影响。结果MiR 107在喉癌组织中的表达显著低于癌旁组织，差异具有统计学意义（P<0.05），miR 107的表达水平与肿瘤细胞分化程度、淋巴结转移及原发部位相关（P<0.05）。细胞实验显示，过表达miR 107后喉癌细胞迁移及侵袭能力明显下降（P<0.05），而敲减miR 107后细胞迁移及侵袭能力明显增强（P<0.05）。结论MiR 107在喉癌中表达显著下调，它能够抑制喉癌细胞的迁移和侵袭能力。