Cross talk, mediated by exosomes, between normal stem cells and cancer stem cells (CSCs) in the tumor microenvironment has been given less attention so far. In addition, no publications are available in the literature that address the in vivo impact of exosomes derived from CSCs and mesenchymal stem cells (MSCs) on progression of long-term hepatocellular carcinoma (HCC). Herein, we hypothesized that transfer of exosomes among the cells in the HCC microenvironment could either induce or inhibit tumor growth and metastasis depending on their source. To check this hypothesis, we investigated the effect of exosomes coming from two different stem cell populations, hepatic CSCs and bone marrow (BM) MSCs, on progression of long-term DEN-induced HCC in rats and the involved underlying mechanisms. CSCs-exosomes induced a significant increase in liver relative weight and serum levels of cancer markers (AFP and GGT) and liver enzymes (ALT, AST, and ALP), intensive immunostaining for the HCC marker GST-P, and an increased number and area of tumor nodules as compared to HCC rats injected by PBS. CSCs-exosomes also decreased apoptosis (marked by downregulation of Bax and p53 and upregulation of Bcl2, and increased immunostaining of PCNA), increased angiogenetic activity (revealed by upregulation of VEGF), enhanced metastasis and invasiveness (indicated by upregulation of P13K and ERK proteins and their downstream target MMP9 and downregulation of TIMP1), and induced epithelial mesenchymal transition (marked by increased serum and hepatic level of TGFβ1 mRNA and protein). Notably, CSCs-exosomes also elevated HCC exosomal microRNA (miR) 21, exosomal long noncoding (lnc) RNA Tuc339, lncHEIH, and the HCC lncHOTAIR and decreased liver miR122 and HCC miRs (miR148a, miR16, and miR125b). All these cellular, functional, and molecular changes were reversed following injection of BM-MSCs-exosomes. However, both CSCs- and MSCs-exosomes failed to change the elevated oxidative stress or the inhibited antioxidant activities induced by HCC. Collectively, our results revealed a tumor stimulatory effect (induction of tumor growth, progression, and metastasis) for exosomes derived from CSCs and an inhibitory effect for exosomes derived from MSCs. These results provide valuable insight on the effect of CSCs- and MSCs-exosomes on HCC growth and progression in vivo, which may be helpful to understand the mechanism of HCC development.

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BackgroundMeningioma tumors arise in arachnoid membranes, and are the most reported central nervous system (CNS) tumors worldwide. Up to 20% of grade I meningioma tumors reoccur and currently predictive cancer stem cells (CSCs) markers for aggressive and drug resistant meningiomas are scarce.MethodsMeningioma tissues and primary cell lines were investigated using whole transcriptome microarray analysis, immunofluorescence staining of CSCs markers (including CD133, Sox2, Nestin, and Frizzled 9), and drug treatment with cisplatin or etoposide.ResultsUnsupervised hierarchical clustering of six meningioma samples separated tissues into two groups. Analysis identified stem cells related pathways to be differential between the two groups and indicated the de-regulation of the stem cell associated genes Reelin (RELN), Calbindin 1 (CALB1) and Anterior Gradient 2 Homolog (AGR2). Immunofluorescence staining for four tissues confirmed stemness variation in situ. Biological characterization of fifteen meningioma primary cell lines concordantly separated cells into two functionally distinct sub-groups. Pleomorphic cell lines (NG type) grew significantly faster than monomorphic cell lines (G type), had a higher number of cells that express Ki67, and were able to migrate aggressively in vitro. In addition, NG type cell lines had a lower expression of nuclear Caspase-3, and had a significantly higher number of CSCs co-positive for CD133+ Sox2+ or AGR2+ BMI1+. Importantly, these cells were more tolerant to cisplatin and etoposide treatment, showed a lower level of nuclear Caspase-3 in treated cells and harbored drug resistant CSCs.ConclusionCollectively, analyses of tissues and primary cell lines revealed stem cell associated genes as potential targets for aggressive and drug resistant meningiomas.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-017-0441-7) contains supplementary material, which is available to authorized users.

Tumor comprises of heterogeneous population of cells where not all the disseminated cancer cells have the prerogative and “in-build genetic cues” to form secondary tumors. Cells with stem like properties complemented by key signaling molecules clearly have shown to exhibit selective growth advantage to form tumors at distant metastatic sites. Thus, defining the role of cancer stem cells (CSC) in tumorigenesis and metastasis is emerging as a major thrust area for therapeutic intervention. Precise relationship and regulatory mechanisms operating in various signal transduction pathways during cancer dissemination, extravasation and angiogenesis still remain largely enigmatic. How the crosstalk amongst circulating tumor cells (CTC), epithelial mesenchymal transition (EMT) process and CSC is coordinated for initiating the metastasis at secondary tissues, and during cancer relapse could be of great therapeutic interest. The signal transduction mechanisms facilitating the dissemination, infiltration of CSC into blood stream, extravasations, progression of metastasis phenotype and angiogenesis, at distant organs, are the key pathologically important vulnerabilities being elucidated. Therefore, current new drug discovery focus has shifted towards finding “key driver genes” operating in parallel signaling pathways, during quiescence, survival and maintenance of stemness in CSC. Understanding these mechanisms could open new horizons for tackling the issue of cancer recurrence and metastasis-the cause of ~90% cancer associated mortality. To design futuristic & targeted therapies, we propose a multi-pronged strategy involving small molecules, RNA interference, vaccines, antibodies and other biotechnological modalities against CSC and the metastatic signal transduction cascade.

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Introduction. Spinal cord injury (SCI) is a life-disrupting condition in which the first few days are the most critical. Secondary conditions remain the main causes of death for people with SCI. The response of different cell types to SCI and their role at different times in the progression of secondary degeneration are not well understood. The aim of this study was to study the histopathological changes of compressed spinal cord injury (CSCI) in a rat model. Material and methods. Forty adult male Sprague-Dawley rats were divided into four groups. In group I, the rats were left without any surgical intervention (control). In group II, the rats were subjected to laminectomy without spinal cord compression (sham-operated). In group III, the rats were sacrificed one day after CSCI. In group IV, the rats were sacrificed seven days after CSCI. The light microscopy was employed to study the morphology using H&E, osmic acid staining and immunohistochemistry to detect glial fibrillary acidic protein (GFAP). The electron microscopy was applied for ultrastructure study. Results. Histopathological examination of the posterior funiculus of the white matter revealed minute hemorrhages and localized necrotic areas on day 1, which transformed to areas of cavitation and fibrinoid necrosis surrounded by a demarcating rim of numerous astrocytes by day 7. The mean percentage of area of GFAP expression increased significantly by day 7. Osmic acid staining revealed swollen nerve fibers after one day, while numerous fibers had been lost by day 7. An ultrastructure study revealed swollen redundant thinned myelin and myelin splitting, as well as degeneration of axoplasm on day 1. On day 7, layers of the myelin sheath were folded and wrinkled with partial or complete demyelination areas. The myelin lamellae were disorganized and loose. The G-ratio was significantly greater on day 1 than day 7 after CSCI. Conclusions. In the rat model of CSCI details of the progressive spinal cord injury can be analyzed by morphological methods and may be helpful in the identification of the onset and type of clinical intervention.