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Glioblastoma stem-like cells (GSCs) are critical for the aggressiveness and progression of glioblastoma (GBM) and contribute to its resistance to adjuvant treatment. MicroRNAs (miRNAs) are small, non-coding RNAs controlling gene expression at the post-transcriptional level, which are known to be important regulators of the stem-like features. Moreover, miRNAs have been previously proved to be promising diagnostic biomarkers in several cancers including GBM. Using global expression analysis of miRNAs in 10 paired in-vitro as well as in-vivo characterized primary GSC and non-stem glioblastoma cultures, we identified a miRNA signature associated with the stem-like phenotype in GBM. 51 most deregulated miRNAs classified the cell cultures into GSC and non-stem cell clusters and identified a subgroup of GSC cultures with more pronounced stem-cell characteristics. The importance of the identified miRNA signature was further supported by demonstrating that a Risk Score based on the expression of seven miRNAs overexpressed in GSC predicted overall survival in GBM patients in the TCGA dataset independently of the IDH1 status. In summary, we identified miRNAs differentially expressed in GSCs and described their association with GBM patient survival. We propose that these miRNAs participate on GSC features and could represent helpful prognostic markers and potential therapeutic targets in GBM.

Dipeptidyl peptidase-IV (DPP-IV) and fibroblast activation protein-α (FAP) are speculated to participate in the regulation of multiple biological processes, because of their unique enzymatic activity, as well as by non-hydrolytic molecular interactions. At present, the role of DPP-IV and FAP in the development and progression of various types of tumors, including glioblastoma, is intensively studied, and their functional crosstalk is hypothesized. In this article, we describe the correlative expression of DPP-IV and FAP mRNA in primary cell cultures derived from human glioblastoma and associated expression dynamics of both molecules in astrocytoma cell lines depending on culture conditions. Although the molecular mechanisms of DPP-IV and FAP co-regulations remain unclear, uncoupled expression of transgenic DPP-IV and the endogenous FAP suggests that it occurs rather at the transcriptional than at the posttranscriptional level. Understanding of the expressional and functional coordinations of DPP-IV and FAP may help clarify the mechanisms of biological roles of both molecules in transformed astrocytic cells.

Proteases are directly involved in cancer pathogenesis. Expression of fibroblast activation protein (FAP) is upregulated in stromal fibroblasts in more than 90% of epithelial cancers and is associated with tumor progression. FAP expression is minimal or absent in most normal adult tissues, suggesting its promise as a target for the diagnosis or treatment of various cancers. Here, we report preparation of a polymer conjugate (an iBody) containing a FAP-specific inhibitor as the targeting ligand. The iBody inhibits both human and mouse FAP with low nanomolar inhibition constants but does not inhibit close FAP homologues dipeptidyl peptidase IV, dipeptidyl peptidase 9, and prolyl oligopeptidase. We demonstrate the applicability of this iBody for the isolation of FAP from cell lysates and blood serum as well as for its detection by ELISA, Western blot, flow cytometry, and confocal microscopy. Our results show the iBody is a useful tool for FAP targeting in vitro and potentially also for specific anticancer drug delivery.

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BackgroundDipeptidyl peptidase-IV (DPP-IV) is suggested to contribute to the pathogenesis of several autoimmune diseases. The aim of this study was to evaluate the association of DPP-IV presence in blood plasma and mononuclear cells with the disease activity in rheumatoid arthritis (RA).MethodsPatients with active RA (n = 27) were examined at the study enrolment and a follow-up examination was performed after the regression of the joint effusions and at least 6 months after the first investigation. The control group comprised patients with a noninflammatory joint disease, i.e. osteoarthritis (OA; n = 15). The DPP-IV-like enzymatic activity was measured by a kinetic fluorimetric method, the concentration of DPP-IV in the blood plasma was determined using ELISA and the expression of DPP-IV in leukocytes was assayed by flow cytometry.ResultsBlood plasma DPP-IV-like enzymatic activity (median ± SD 220.15 ± 83.6 pkat/mL in RA vs. 376.9 ± 144.9 pkat/mL in OA, p < 0.001) and concentrations (median ± SD 465.1 ± 215.6 ng/mL in RA vs. 953.3 ± 368.4 ng/mL in OA, p < 0.001) were lower in patients with active RA compared to OA. In RA patients, the blood plasma DPP-IV-like enzymatic activity negatively correlated with the CRP concentration (r = −0.39, p = 0.044). No significant differences were observed in the DPP-IV-like enzymatic activity and DPP-IV expression in blood mononuclear cells between the RA and OA groups. At follow-up, 18 RA patients had a less active disease as demonstrated by an improved DAS28 score. In this group, comparison of the entry and the follow-up values in individual patients revealed an increase of the blood plasma DPP-IV-like enzymatic activity (median ± SD 141 ± 46 % of the patient’s entry values, p = 0.011) and DPP-IV concentration (median ± SD 168 ± 25 %, of the patient’s entry values, p = 0.033). In contrast to the blood plasma, the DPP-IV expression in blood mononuclear cells was reduced in these patients as evidenced by a decrease in the cell surface DPP-IV-like enzymatic activity as well as the median fluorescence intensity of DPP-IV staining in lymphocytes (median ± SD 66 ± 56 %, p = 0.018 and 63 ± 31 % of the patient’s entry values, p = 0.005, respectively).ConclusionsThe association between RA activity and the changes in blood plasma and blood mononuclear cell DPP-IV in individual patients supports the possible relationship of DPP-IV to RA pathophysiology.

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