- Regulation of cancer cell membrane proteases, namely "Dipeptidyl peptidase IV activity and/or structure homologues“ (DASH) in cells of neuroectodermal origin
- Role of membrane proteases in glial tumour oncogenesis, namely in the regulation of cell proliferation, differentiation, invasion and tumour progression
- Role of membrane proteases in cell signaling. Prereceptor proteolytic modification of biologically active peptides by DASH molecules and its role in signal transduction diversification
- Morphological and cytochemical changes evoked by tumoricide factors used in medical practice (hyperoxidation due to the photodynamic effect; effects of cytostatics, neutron -capture reaction etc.)
- Pathogenetic role of local and systemic DASH molecules and their functional partners in rheumatoid arthritis
Our work demonstrated existence of cell specific expression patterns of DASH molecules in transformed neuroectodermal cells of differing degree of malignity and under varying growth conditions. The results of other authors also support the importance of the "DASH system" (comprising DASH molecules, namely those localized in the plasma membrane, their biologically active substrates and corresponding receptors) in the processes of cancer development (Wesley et al. 2004, Chen and Kelly 2003). Our results, obtained using human bioptic material, original cell clones with regulated expression of some DASH molecules and their mutated variants and animal studies suggest the coregulation of DASH molecules and receptors of their biologically active substrates. As an example, we described codistribution of DPP-IV and FAP as well as DPP-IV and chemokine receptor CXCR4 in human glioblastoma (Stremenova et al. 2007).
A phylogenetic tree of DPP-IV family protein sequence relationships. Distances represent relationship predicted after alignment using the CLUSTAL2 algorithm followed by PHYLIP analysis (Genbank accession numbers: DPP4: NP_001926;DPP6.1: NP_570629; DPP6.2: NP_001927; DPP7/DPPII/QPP: NP_037511; DPP8.1: NP_569118; DPP8.2: NP_060213; DPP8.3: NP_932064;DPP8.4: NP_932065; DPP9: NP_631898; DPP10-S: NP_001004360; DPP10-L: NP_065919; FAP-alpha/seprase: NP_004451). The blue boxes indicate enzymatically active proteins and the brown boxes indicate members with no dipeptidyl peptidase-IV enzymatic activity. All proteins are members of the SC clan representing enzymes with an alpha/beta-hydrolase fold; family S9B represents the dipeptidyl peptidase-IV family, whereas peptidase family S28 contains the DPP-IV-sequence divergent DPP7/DPPII/QPP. DPP6 and DPP10 are classified as S9 homologs with no peptidase activity. The Family descriptor is followed by the unique family identifier under which the general substrate specificity is indicated (http://merops.sanger.ac.uk/cgi-bin/name_index?id = P;action = A). To the right of each colored box are listed known interactions/functionalities believed to be independent of enzymatic activity (Sedo et al, 2008).
Our hypothesis about the possible role of the novel group of DASH molecules in cancer biology is reviewed in Int J Biochem Cell Biol. 36, 408-421, 2004 and Front Biosci. 2008 Jan 1;13:2319-26. Some of our results also suggest potential use of DASH molecules for clinical medicine and diagnostics, including nonmalignant diseases (Stremenova et al. 2007 and 2010, Sedo et al. 2008, Sromova et al. 2010, Stulc and Sedo 2010).
A complex portfolio of biochemical, immunochemical and cell and molecular biology methods, including regulated expression of transgenic products, mutation studies, confocal microscopy, flow cytometry and homotopic xenotransplantations under stereotactic control.
|In vivo imaging of orthotopically implanted glioma cells transfected with a fluorescent protein mKate2. Images were taken at 1 (figure A) and 5 weeks (figure B) after implantation
Localization of DPP-IV and FAP in U87 (A) and U138 cell lines (B).
- The diagnostic and therapeutic potential of fibroblast activation protein (FAP) in human astrocytic tumors. (2011-2015, Internal Grant Agency of the Ministry of Health of the Czech Republic, project NT12237-5)
- Complex oncological program. (2012-2016, Charles University Research Development Schemes, project P27/LF1/1)
- Molecular heterogeneity of dipeptidyl peptidase-IV (DPP-IV) and fibroblast activation protein alpha (FAP) and its association with WHO grade of human astrocytic tumors. (2012-2014 Charles University Grant Agency, project 671612)
- Novel concepts for the therapeutic targeting of tumor microenvironment in human glioblastomas. (2015-18; Agency for Medical Research of the Ministry of Health of the Czech Republic, project …)
- Early Diagnosis of Pancreatic Adenocarcinoma: Surface Proteases and Specific Biomarkers. (2013-2015, Internal Grant Agency of the Ministry of Health of the Czech Republic, project NT14254-3)
- Mechanisms of reprogramming of complex cellular processes. (2012-2017, University Research Centers, project UNCE 204013)
- The importance of the tumor microenvironment in gliomagenesis. (2014-2016, Charles University Grant Agency, project 44214)