Exosomal miR-155-5p promotes proliferation and migration of gastric cancer cells by inhibiting TP53INP1 expression

Exosomal microRNA (miRNA) secreted by tumor cells plays an important biological role in tumorigenesis and development. We aimed to explore the effects of exosomal miR-155-5p in gastric cancer (GC) and understand its mechanism of action in GC progression. We isolated exosomes from the human gastric mucosal epithelial cell line GES-1 and gastric cancer cell line AGS, and then identified them according to their surface markers by flow cytometry. Later, we detected the miR-155-5p expression levels in tissues and isolated exosomes using RT-qPCR. Bioinformatics analysis showed that miR-155-5p directly binds to the 3' untranslated region (3'-UTR) of tumor protein p53-induced nuclear protein 1 (TP53INP1) mRNA. We also investigated whether the miR-155-5p-rich exosomes caused changes in cell cycle, proliferation, and migration in AGS cells. In this study, we found that the levels of miR-155-5p were significantly increased in GC tissues and AGS cells, and that the TP53INP1 protein level was downregulated in GC tissues using IHC and IFC. TP53INP1 was found to be directly regulated by miR-155-5p following a dual luciferase-based reporter assay. After co-culturing with the isolated miR-155-5p-rich exosomes, the proliferation and migration capabilities of AGS cells were enhanced. Thus, our results reveal that exosomal miR-155-5p acts as an oncogene by targeting TP53INP1 mRNA in human gastric cancer.     

Exosomes Derived from Glioma Cells under Hypoxia Promote Angiogenesis through Up-regulated Exosomal Connexin 43

Glioblastoma multiform (GBM) is a highly aggressive primary brain tumor. Exosomes derived from glioma cells under a hypoxic microenvironment play an important role in tumor biology including metastasis, angiogenesis and chemoresistance. However, the underlying mechanisms remain to be elucidated. In this study, we aimed to explore the role of connexin 43 on exosomal uptake and angiogenesis in glioma under hypoxia. U251 cells were exposed to 3% oxygen to achieve hypoxia, and the expression levels of HIF-1α and Cx43, involved in the colony formation and proliferation of cells were assessed. Exosomes were isolated by differential velocity centrifugation from U251 cells under normoxia and hypoxia (Nor-Exos and Hypo-Exos), respectively. Immunofluorescence staining, along with assays for CCK-8, tube formation and wound healing along with a transwell assay were conducted to profile exosomal uptake, proliferation, tube formation, migration and invasion of HUVECs, respectively. Our results revealed that Hypoxia significantly up-regulated the expression of HIF-1α in U251 cells as well as promoting proliferation and colony number. Hypoxia also increased the level of Cx43 in U251 cells and in the exosomes secreted. The uptake of Dio-stained Hypo-Exos by HUVECs was greater than that of Nor-Exos, and inhibition of Cx43 by ^37,43gap27 or lenti-Cx43-shRNA efficiently prevented the uptake of Hypo-Exos by recipient endothelial cells. In addition, the proliferation and total loops of HUVECs were remarkably increased at 24 h, 48 h, and 10 h after Hypo-Exos, respectively. Notably, ^37,43gap27, a specific Cx-mimetic peptide blocker of Cx37 and Cx43, efficiently alleviated Hypo-Exos-induced proliferation and tube formation by HUVECs. Finally, ^37,43gap27 also significantly attenuated Hypo-Exos-induced migration and invasion of HUVECs. These findings demonstrate that exosomal Cx43 contributes to glioma angiogenesis mediated by Hypo-Exos, and suggests that exosomal Cx43 might serve as a potential therapeutic target for glioblastoma.     

Exosomes in tumor microenvironment influence cancer progression and metastasis

Exosomes are small membrane vesicles of endocytic origin with a size of 50–100 nm. They can contain microRNAs, mRNAs, DNA fragments, and proteins, which are shuttled from a donor cell to recipient cells. Many different cell types including immune cells, mesenchymal cells, and cancer cells release exosomes. There is emerging evidence that cancer-derived exosomes contribute to the recruitment and reprogramming of constituents associated with tumor environment. Here, we discuss different mechanisms associated with biogenesis, payload, and transport of exosomes. We highlight the functional relevance of exosomes in cancer, as related to tumor microenvironment, tumor immunology, angiogenesis, and metastasis. Exosomes may exert an immunosuppressive function as well as trigger an anti-tumor response by presenting tumor antigens to dendritic cells. Exosomes may serve as cancer biomarkers and aid in the treatment of cancer.     

Molecular determinants of ovarian cancer plasticity

During development, the formation and remodeling of primary vascular networks occurs by vasculogenesis and angiogenesis. Recently, the term "vasculogenic mimicry" has been used by our laboratory and collaborators to reflect the embryonic-like ability of aggressive, but not nonaggressive, melanoma tumor cells to form a pattern of matrix-rich networks (containing channels) surrounding spheroids of tumor cells in three-dimensional culture, concomitant with their expression of vascular cell markers. Ovarian cancer is usually diagnosed as advanced stage disease in most patients when widespread metastases have already been established within the peritoneal cavity. In this study, we explored whether invasive ovarian carcinoma cells could engage in molecular vasculogenic mimicry reflected by their plasticity, compared with their normal cell counterparts. The data revealed that the invasive ovarian cancer cells, but not normal ovarian surface epithelial cells, formed patterned networks containing solid and hollow matrix channels when grown in three-dimensional cultures containing Matrigel or type I collagen, in the absence of endothelial cells or fibroblasts. Immunohistochemical analysis showed that matrix metalloproteinases (MMP)-1, -2, and -9, and MT1-MMP were discretely localized to these networks, and the formation of the networks was inhibited by treatment with MMP inhibitors. Furthermore, the RNase protection assay revealed the expression of multiple vascular cell-associated markers by the invasive ovarian cancer cells. In patient tumor sections from high-stage, high-grade ovarian cancers, 7 to 10% of channels containing red blood cells were lined by tumor cells. By comparison, all vascular areas in benign tumors and low-stage cancers were endothelial lined. These results may offer new insights and molecular markers for consideration in ovarian cancer diagnosis and treatment strategies based on molecular vascular mimicry by aggressive tumor cells.     

A doxorubicin delivery platform using engineered natural membrane vesicle exosomes for targeted tumor therapy

Targeted drug delivery vehicles with low immunogenicity and toxicity are needed for cancer therapy. Here we show that exosomes, endogenous nano-sized membrane vesicles secreted by most cell types, can deliver chemotherapeutics such as doxorubicin (Dox) to tumor tissue in BALB/c nude mice. To reduce immunogenicity and toxicity, mouse immature dendritic cells (imDCs) were used for exosome production. Tumor targeting was facilitated by engineering the imDCs to express a well-characterized exosomal membrane protein (Lamp2b) fused to αv integrin-specific iRGD peptide (CRGDKGPDC). Purified exosomes from imDCs were loaded with Dox via electroporation, with an encapsulation efficiency of up to 20%. iRGD exosomes showed highly efficient targeting and Dox delivery to αv integrin-positive breast cancer cells in vitro as demonstrated by confocal imaging and flow cytometry. Intravenously injected targeted exosomes delivered Dox specifically to tumor tissues, leading to inhibition of tumor growth without overt toxicity. Our results suggest that exosomes modified by targeting ligands can be used therapeutically for the delivery of Dox to tumors, thus having great potential value for clinical applications.     

Tumor cell cross talk with tumor-associated leukocytes leads to induction of tumor exosomal fibronectin and promotes tumor progression

Exosomes participate in intercellular communication, but most data published are based on exosomes released from in vitro cultured cells that do not communicate with neighboring cells located in the same microenvironment as the exosomal-producing cells in vivo. In this study, our data show that co-culture of leukocytes isolated from breast tumor tissue leads to uptake of fibronectin (FN) on or in the tumor exosomes (Exo(fib+)). The induction of FN and exosomal uptake is tumor tissue derived and leukocyte specific, because leukocytes isolated from the peripheral blood of na?ve mice failed to induce FN uptake by tumor exosomes. Furthermore, depletion of both CD25(+) cells and Gr-1(+) cells from tumor-associated leukocytes causes a reduction of Exo(fib+), suggesting that tumor-associated CD25(+) cells and Gr-1(+) cells participate in FN production and uptake by tumor exosomes, resulting in Exo(fib+). As a result of tumor cells absorbing Exo(fib+), two major events are induced: focal adhesion kinase/Src-dependent signaling pathways are activated, and the production of proinflammatory cytokines and metalloproteinase 9 is enhanced in response to absorbing exosomes. This, in turn, enhances tumor cell invasion in vitro and in vivo. Collectively, our findings provide evidence that exosomes released from freshly excised tumor tissue cells that have communicated/interacted with immune cells gain new immune evasion capacity.     

Exosomes/microvesicles: mediators of cancer-associated immunosuppressive microenvironments

Cancer cells, both in vivo and in vitro, have been demonstrated to release membranous structures, defined as microvesicles or exosomes, consisting of an array of macromolecules derived from the originating cells, including proteins, lipids, and nucleic acids. While only recently have the roles of these vesicular components in intercellular communication become elucidated, significant evidence has demonstrated that tumor exosomes can exert a broad array of detrimental effects on the immune system—ranging from apoptosis of activated cytotoxic T cells to impairment of monocyte differentiation into dendritic cells, to induction of myeloid-suppressive cells and T regulatory cells. Immunosuppressive exosomes of tumor origin can be found within neoplastic lesions and in biologic fluids from cancer patients, implying a potential role of these pathways in in vivo tumor progression and systemic paraneoplastic syndromes. Through the expression of molecules involved in angiogenesis promotion, stromal remodeling, signaling pathway activation through growth factor/receptor transfer, chemoresistance, and genetic intercellular exchange, tumor exosomes could represent a central mediator of the tumor microenvironment. By understanding the nature of these tumor-derived exosomes/microvesicles and their roles in mediating cancer progression and modulating the host immune response will significantly impact therapeutic approaches targeting exosomes.     

Expression of Rsf-1, a chromatin-remodeling gene, in ovarian and breast carcinoma

Rsf-1 protein is a member of a chromatin-remodeling complex that plays an important role in regulating gene expression and cell proliferation. Our previous study showed that Rsf-1 was an amplified gene that participated in the development of ovarian serous carcinoma. To further elucidate the role of Rsf-1 in ovarian cancer, we studied Rsf-1 immunoreactivity in 294 ovarian tumors of various histologic types. Because the Rsf-1 amplicon overlaps an amplified region reported in breast cancer, we included 782 neoplastic and normal breast tissues for comparison. Immunohistochemistry was performed on tissue microarrays using a 4-tiered scoring system. Overexpression of Rsf-1 was defined as a nuclear immunointensity of 3+ to 4+ because of a strong correlation between 3+ and 4+ immunointensity and Rsf-1 gene amplification, based on our previous fluorescence in situ hybridization analysis. Rsf-1 overexpression was observed in 25% of high-grade ovarian serous carcinomas and in only rare cases (<7%) of low-grade ovarian serous, ovarian endometrioid, and invasive breast carcinomas but not in any ovarian serous borderline tumors, ovarian clear cell carcinomas, ovarian mucinous carcinomas, intraductal carcinomas of the breast, and normal ovaries and breast tissues. Thus, overexpression of Rsf-1 was significantly associated with high-grade ovarian serous carcinoma (P < .05), as compared with other types of ovarian tumors and breast carcinomas. Our results provide evidence that Rsf-1 expression is primarily confined to high-grade serous carcinoma, the most aggressive ovarian cancer. Because Rsf-1 overexpression occurs in only a small number of breast carcinomas, it is unlikely that Rsf-1 is a critical gene in the development of breast carcinoma.     

长链非编码RNA PVT1调控miR-551通过Wnt信号通路对卵巢癌迁移和侵袭的影响

目的:探讨长链非编码RNA PVT1在卵巢癌组织中的表达情况及其在卵巢癌细胞迁移和侵袭过程中的作用及机制。方法:q PCR检测卵巢癌和正常卵巢组织及不同卵巢癌细胞中PVT1的表达情况;Transwell侵袭实验和细胞划痕实验分别检测沉默PVT1后卵巢癌细胞侵袭和迁移能力的变化;双萤光素酶报告基因检测PVT1与微小RNA(miR)-551的相互作用;Transwell侵袭实验和细胞划痕实验分别检测沉默PVT1后miR-551-inhibitor对卵巢癌细胞侵袭和迁移能力的影响;Western blot法检测沉默PVT1后Wnt信号通路相关蛋白的表达情况。裸鼠皮下成瘤实验检测沉默PVT1对卵巢癌成瘤重量及体积的影响。结果:与正常卵巢组织相比,卵巢瘤组织中PVT1表达明显增高(P0.05);卵巢癌细胞株ES-2中PVT1表达水平最高(P0.05);沉默PVT1可以抑制卵巢癌细胞侵袭和迁移能力;PVT1能与miR-551的位点特异性结合;沉默PVT1后,miR-551-inhibitor可以促进卵巢癌细胞侵袭和迁移能力;沉默PVT1后Wnt信号通路蛋白的表达相应下调;与阴性对照组相比,PVT1-siRNA组荷瘤小鼠肿瘤体积和重量都明显减小(P0.05)。结论:PVT1在卵巢癌发生发展过程中起重要作用,它可以靶向调节miR-551,通过Wnt信号通路调控卵巢癌细胞的侵袭和迁移能力。     

肝细胞癌患者血清外泌体中 PD-L1 的表达及其临床意义

目的 探究肝细胞癌 ( hepatocellular carcinoma, HCC) 患者血清外泌体中程序性死亡配体-1 (programmed death ligand 1, PD-L1) 的表达水平及临床意义。 方法 采用 ExoQuick 试剂盒提取 75 例 HCC 患者和 15 名健康对照者血清样本中的外泌体, 分别利用透射电镜、 NanoSight 以及 Western 印迹对其进行鉴 定; 采用 RT-qPCR 检测血清外泌体中 PD-L1 mRNA 的表达差异; 采用卡方检验分析血清外泌体 PD-L1 mRNA 表达水平与患者临床病理学特征的关系; 采用 Kaplan-Meier 法结合 Cox 回归分析探究血清外泌体 PD-L1 mRNA 表达的预后价值。 结果 透射电镜和 NanoSight 结果显示 HCC 患者和健康对照者血清中的外泌体粒 径主要集中 100 nm 左右, Western 印迹检测可见外泌体均表达 CD9 和 TSG101 标志蛋白, 而不表达细胞骨 架蛋白 Calnexin。 RT-qPCR 检测结果显示, HCC 患者血清外泌体中 PD-L1 mRNA 的表达水平明显高于健康 对照者 (t = 11. 670, P< 0. 001), 其高表达与肿瘤直径、 肿瘤数目、 Child-Pugh 分级、 AFP 水平以及门静脉 癌栓有关 (P均 < 0. 05)。 Kaplan-Meier 生存分析显示, 血清外泌体 PD-L1 mRNA 高表达组 HCC 患者的总生 存期较低表达组明显缩短 (P = 0. 004)。 单因素和多因素 Cox 回归分析表明, 血清外泌体 PD-L1 mRNA 高 表达是 HCC 患者总生存期缩短的独立危险因素 (HR = 2. 013, 95 % CI: 1. 012 ~ 3. 669, P = 0. 015)。 结论 HCC 患者血清外泌体中 PD-L1 表达明显上调, 且与肿瘤的恶性进展和不良预后密切相关, 具有成为 HCC 预后标志物的巨大潜力。     

Proteomic analysis of exosomes isolated from human malignant pleural effusions

Exosomes are membrane vesicles from endosomal origin secreted by various cells such as hematopoietic, epithelial, and tumor cells. Exosomes secreted by tumor cells contain specific antigens potentially useful for immunotherapeutic purposes. Our aim was to determine if exosomes are present in human cancerous pleural effusions and to identify their proteomic content. Exosomes were purified by sucrose gradient ultracentrifugation, and electron microscopy was used to check both concentration and purity of exosomes. Proteins were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and protein bands were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and Western blotting. Exosomes were present in pleural fluid obtained from patients suffering from mesothelioma (n = 4), lung cancer (n = 2), breast cancer (n = 2), and ovarian cancer (n = 1). As previously reported by others, antigen-presenting molecules, cytoskeletal proteins, and signal transduction-involved proteins were present. Proteins not previously reported were identified (SNX25, BTG1, PEDF, thrombospondin 2). Different types of immunoglobulins and complement factors were abundantly present in the sucrose fractions containing exosomes. Exosome-directed specificity of these immunoglobulins was not observed. In conclusion, sucrose gradient ultracentrifugation allows isolation of exosomes from malignant pleural effusions. However, pleural fluid proteins and especially immunoglobulins are coisolated and may hamper the use of exosomes isolated from malignant effusion for immunotherapy programs.     

MDA-MB-231细胞在乏氧条件下通过外泌体传递miR-221、miR-222增强乳腺癌细胞侵袭和迁移能力

目的探讨乳腺癌细胞MDA-MB-231在乏氧条件下分泌的外泌体对肿瘤细胞侵袭和迁移的影响。方法利用差速离心法分离外泌体,并通过动态光散射和透射电镜对外泌体的粒径、形态进行表征。通过对外泌体进行PKH26染色,进而观察肿瘤细胞对外泌体的摄取情况。应用qRT-PCR法检测肿瘤细胞及外泌体中miR-221、miR-222的含量。Transwell侵袭实验和细胞划痕实验检测MDA-MB-231细胞的侵袭和迁移能力。Western blot法检测MDA-MB-231细胞中上皮细胞-间质转化(epithelial-mesenchymal transition,EMT)相关蛋白(E-cadherin、N-cadherin和vimentin)的表达。结果MDA-MB-231细胞经乏氧处理后,其侵袭和迁移能力增强,并且N-cadherin和vimentin的表达上调;乏氧处理的肿瘤细胞分泌的外泌体通过传递miR-221、miR-222,促进MDA-MB-231细胞的EMT进展。结论MDA-MB-231细胞在乏氧条件下,可以通过外泌体传递miR-221、miR-222增加癌细胞侵袭和迁移能力。     

Non-compliance is the predominant cause of aspirin resistance in chronic coronary arterial disease patients

Advances in cancer therapy have been substantial in terms of molecular understanding of disease mechanisms, however these advances have not translated into increased survival in the majority of cancer types. One unsolved problem in current cancer therapeutics is the substantial immune suppression seen in patients. Conventionally, investigations in this area have focused on antigen-nonspecific immune suppressive molecules such as cytokines and T cell apoptosis inducing molecules such as Fas ligand. More recently, studies have demonstrated nanovesicle particles termed exosomes are involved not only in stimulation but also inhibition of immunity in physiological conditions. Interestingly, exosomes secreted by cancer cells have been demonstrated to express tumor antigens, as well as immune suppressive molecules such as PD-1L and FasL. Concentrations of exosomes from plasma of cancer patients have been associated with spontaneous T cell apoptosis, which is associated in some situations with shortened survival. In this paper we place the "exosome-immune suppression" concept in perspective of other tumor immune evasion mechanisms. We conclude by discussing a novel therapeutic approach to cancer immune suppression by extracorporeal removal of exosomes using hollow fiber filtration technology     

NFATc1对裸鼠上皮性卵巢癌移植瘤脉管生成的影响

 目的: 探讨胞浆活化T细胞核因子1(nuclear factor of activated T-cells, cytplasmic 1, NFATc1)对人卵巢癌SKOV3细胞裸鼠移植瘤生长和肿瘤脉管生成的影响及其可能机制。方法: NFATc1 siRNA转染人上皮性卵巢癌细胞株SKOV3,免疫荧光及RT-PCR测量转染效率和基因抑制率,选取效率最高的序列建立裸鼠皮下移植瘤模型, 测量各组裸鼠肿瘤体积,观察NFATc1 siRNA的体内抗肿瘤作用。免疫组织化学检测各组肿瘤组织NFATc1的表达情况,并使用细胞角蛋白染色标记上皮性来源,CD34标记微血管,podoplanin标记微淋巴管。分别计算各组微血管及微淋巴管密度并进行统计学分析。应用RT-PCR及Western blot检测各组移植瘤组织NFATc1、CXC趋化因子受体2(CXCR2)、成纤维细胞生长因子2(FGF-2)及血小板源性生长因子BB(PDGF-BB)的mRNA及蛋白表达水平。结果: 3条特异性序列均可显著降低NFATc1的表达水平,以siRNA-1169最佳。NFATc1在空白组及阴性对照组瘤组织高表达。干扰组抑瘤率为57.08%,且重量和体积均低于2个对照组。空白组和阴性对照组的微血管密度和微淋巴管密度明显高于干扰组。对照组比较,NFATc1 siRNA可以在mRNA水平上明显抑制NFATC1、CXCR2、FGF-2和PDGF-BB的转录。Western blot各组细胞在相应位置出现NFATc1、CXCR2、FGF-2和 PDGF-BB条带,空白组与阴性对照组的吸光度最强,与干扰组比较具有显著差异。结论: NFATc1 siRNA明显抑制人卵巢癌SKOV3细胞裸鼠皮下移植瘤生长和肿瘤脉管生成,下调CXCR2、FGF-2及PDGF-BB的表达可能为其途径之一。     

胰腺癌细胞外泌体通过激活线粒体凋亡途径促进β细胞凋亡

目的:探讨胰腺癌细胞分泌的外泌体(exosome)对胰岛β细胞存活率和功能的影响及作用机制。方法:采用外泌体提取试剂盒提取小鼠胰腺癌细胞Pan02和MPC-83上清液外泌体,经磷钨酸染色后于透射电镜下鉴定形态;外泌体经荧光标记后与小鼠胰岛瘤MIN6细胞共孵育48 h,检测外泌体分泌水平和MIN6细胞的摄取水平;MTT和葡萄糖刺激的胰岛素分泌(GSIS)实验分别检测各组细胞的存活率和胰岛素分泌功能;q PCR检测微小RNA-204(miR-204)和Bcl-2 mRNA的表达;Western blot检测线粒体凋亡信号通路相关蛋白Bcl-2、Bax、caspase-3和细胞色素C(Cyt-C)的表达。结果:透射电镜结果显示2种胰腺癌细胞均能分泌外泌体,且Pan02细胞分泌更多。荧光标记的外泌体与胰岛β细胞共孵育结果显示,β细胞能够大量摄取胰腺癌细胞分泌的外泌体。MTT和GSIS实验结果显示,外泌体处理组的MIN6细胞存活率和高糖刺激的胰岛素分泌量显著低于未处理组(P0.01)。q PCR结果显示胰腺癌细胞分泌的外泌体富含miR-204,且外泌体处理后的MIN6细胞内Bcl-2的mRNA表达显著下调(P0.01)。Western blot结果显示,外泌体处理的MIN6细胞内Bcl-2蛋白表达显著下调(P0.05),Bax、cleaved caspase-3和Cyt-C蛋白表达显著上调(P0.01)。结论:胰腺癌细胞能够分泌外泌体,且该外泌体能够被胰岛β细胞摄取。胰腺癌细胞分泌的外泌体可以降低β细胞存活率和β细胞胰岛素的分泌功能,其机制可能通过外源性上调β细胞内miR-204的表达,进而抑制Bcl-2的mRNA和蛋白表达,最终激活β细胞内线粒体凋亡信号通路。     

Increased tissue immunoexpression of YKL-40 protein in high grade serous ovarian cancers

YKL-40 is a glycoprotein secreted by numerous human cells, such as cartilage, synovial, and endothelial cells. The biological role of YKL-40 has not yet been fully unveiled, however, its participation is perceived in angiogenesis, growth, proliferation, differentiation, and remodeling processes. The primary goal of our study was to evaluate possible differences in tissue immunoexpression of YKL-40, assumed between high grade and low-grade ovarian cancers and between the above-mentioned cancer types and benign lesions. Another purpose was to find out whether immunoexpression of the studied protein could correlate with the tumor proliferation process, evaluated by Ki-67 immunoexpression.The analysis comprised 45 women, diagnosed and treated for epithelial ovarian tumors at the Medical University of Lodz between 1997 and 2002. YKL-40 protein immunoexpression was semiquantitatively assessed, whereas immunoexpression of Ki-67 was evaluated using a computer image analysis system. Significantly higher immunoexpression values of both examined proteins were observed in high-grade serous ovarian cancers vs. low-grade and benign tumors. Moreover, a significant positive correlation was identified between the immunoexpressions of YKL-40 and Ki-67 proteins in the studied groups of tumors.In conclusion, the obtained data suggest an overt prominence of TKL-40 tissue immunoexpression of YKL-40 in high-grade serous ovarian tumors, which could then be approached as a helpful, additional marker to identify more aggressive ovarian cancers.     

Mast cells and angiogenesis in pancreatic ductal adenocarcinoma

Mast cells are recognized as critical components of the tumor stromal microenvironment in several solid and hematological malignancies, promoting angiogenesis and tumor growth. A correlation between mast cells infiltration, angiogenesis and tumor progression has been reported for pancreatic ductal adenocarcinoma as well. Mast cells contribute to the aggressiveness of the pancreatic ductal carcinoma enhancing the expression of several pro-angiogenic factors such as vascular endothelial growth factor, fibroblast growth factor-2, platelet-derived growth factor and angiopoietin-1 as well as stimulating the pancreatic cancer cells proliferation by IL-13 and tryptase. The disruption of this pro-angiogenic and proliferative stimulation by inhibiting the mast cells migration and degranulation is under investigation as a potential therapeutic approach in pancreatic ductal adenocarcinoma patients. This review will summarize the literature concerning the mast cells infiltration in the pancreatic ductal adenocarcinoma analyzing its role in angiogenesis and tumor progression.     

Exosomes – Structure,Biogenesis and Biological Role in Non‐Small‐Cell Lung Cancer

Many different cells produce and release membraneous microvesicles (MV) or exosomes into their microenvironment. Exosomes represent a specific subtype of secreted derived vesicles which are defined as homogenous vesicles of 30–100 nm lined by a lipid bilayer, which contain a specific set of proteins, lipids, and nucleic acids. There are clear evidences that they serve as important biological signals messengers and carriers in physiological as well as in pathological processes. Those derived from tumours (tumour‐derived exosomes, TD‐exosomes) function as protumourigenic factors that can mediate intercellular communication in the tumour microenvironment and also contribute to cancer progression. The main functions of exosomes in the cancer microenvironment include the following: promotion of primary cancer growth, stimulation of angiogenesis, activation of stromal fibroblasts, sculpting the cancer ECM, generation of a premetastatic niche and suppression of host immune response. Exosomes have recently emerged as potentially promising diagnostic and prognostic biomarkers in cancer and other diseases. This article is a summary of information about the structure and origin of exosomes and also indicates the importance of exosomes and microRNAs in lung cancer. The role of exosomes in NSCLC is little known, and its explanation requires thorough research.     

Knockdown of TFPI-2 promotes migration and invasion of glioma cells

Glioblastoma is the most malignant primary brain tumor. Due to its highly promigratory and proinvasive properties, standard therapy including surgery, chemotherapy and radiation fails in eradicating this highly aggressive type of cancer. Here, we evaluated the role of TFPI-2, a Kunitz-type serine protease inhibitor, which has been previously described as a tumor suppressor gene in several types of cancer, including glioma. TFPI-2 expression was absent in five of nine investigated high-grade glioma cell lines. Lentiviral knockdown of TFPI-2 in two of the TFPI-2-expressing cell lines (MZ-18 and Hs 638) was associated with pronounced changes in the cellular behavior: glioma cell proliferation, migration and invasion were significantly increased in TFPI-2 knockdown cells in comparison to empty vector-transfected control cells. Since TFPI-2 might exert its tumor suppressor function by inhibiting MMPs, we subsequently analyzed the effects of specific MMP inhibitors on cell invasion of TFPI-2 KD cells vs. control cells. The data obtained from these experiments suggest that the anti-invasive properties of TFPI-2 are associated with inhibition of MMP-1 and MMP-2, while inhibition of MMP-9 seems to play a minor role in this context. Our findings underscore the important role of TFPI-2 as a tumor suppressor gene and indicate that TFPI-2 may be a useful diagnostic marker for the aggressive phenotype of glial tumors.