Publications by authors named "Evzen Krepela"

Brain metastases are a very common and serious complication of oncological diseases. Despite the vast progress in multimodality treatment, brain metastases significantly decrease the quality of life and prognosis of patients. Therefore, identifying new targets in the microenvironment of brain metastases is desirable.

View Article and Find Full Text PDF

The proline-specific serine protease fibroblast activation protein (FAP) can participate in the progression of malignant tumors and represents a potential diagnostic and therapeutic target. Recently, we demonstrated an increased expression of FAP in glioblastomas, particularly those of the mesenchymal subtype. Factors controlling FAP expression in glioblastomas are unknown, but evidence suggests that transforming growth factor beta (TGFbeta) can trigger mesenchymal changes in these tumors.

View Article and Find Full Text PDF

As the genomic region containing the Bcl-2-related ovarian killer (BOK) locus is frequently deleted in certain human cancers, BOK is hypothesized to have a tumor suppressor function. In the present study, we analyzed primary non-small-cell lung carcinoma (NSCLC) tumors and matched lung tissues from 102 surgically treated patients. We show that BOK protein levels are significantly downregulated in NSCLC tumors as compared to lung tissues (p < 0.

View Article and Find Full Text PDF

Human tumor xenografts in mice together with the species-specific analysis of expressed genes allow to study the molecular processes driving tumor growth and progression in vivo and help to develop and evaluate anticancer therapies. In the present work, we designed and validated species-specific real-time RT-PCR assays for discrimination and quantitation of expression of human and mouse transcripts in cancer and stromal cells including dipeptidyl peptidase (DPP) 4, DPP8, DPP9, fibroblast activation protein (FAP) and CXC chemokine receptor 4 in mixed human-mouse biological samples. Using single species RNA samples and mixed human-mouse RNA samples, we formulated and characterized two-step real-time RT-PCR assays to quantitate expression of the indicated transcripts and described analytical performance of the assays.

View Article and Find Full Text PDF

Glioblastomas are deadly neoplasms resistant to current treatment modalities. Fibroblast activation protein (FAP) is a protease which is not expressed in most of the normal adult tissues but is characteristically present in the stroma of extracranial malignancies. FAP is considered a potential therapeutic target and is associated with a worse patient outcome in some cancers.

View Article and Find Full Text PDF

The intrinsic apoptosis pathway represents an important mechanism of stress-induced death of cancer cells. To gain insight into the functional status of the apoptosome apparatus in non-small cell lung carcinoma (NSCLC), we studied its sensitivity to activation, the assembly of apoptosome complexes and stability of their precursors, and the importance of X-linked inhibitor of apoptosis (XIAP) in the regulation of apoptosome activity, using cell-free cytosols from NSCLC cell lines and NSCLC tumours and lungs from 62 surgically treated patients. Treatment of cytosol samples with cytochrome c (cyt-c) and dATP induced proteolytic processing of procaspase-9 to caspase-9, which was followed by procaspase-3 processing to caspase-3, and by generation of caspase-3-like activity in 5 of 7 studied NSCLC cell lines.

View Article and Find Full Text PDF

The Apaf-1 interacting protein (APIP) and the uveal autoantigen with coiled coil domains and ankyrin repeats (UACA) belong to endogenous regulators of the apoptosome apparatus, but their role in tumourigenesis and progression of non-small cell lung carcinoma (NSCLC) is not known. Previous studies demonstrated that APIP inhibits the apoptosome-mediated procaspase-9 activation while UACA induces translocation of Apaf-1 from the cytoplasm into the nucleus. Here, we report for the first time that the expression of APIP and UACA genes is down-regulated on the level of both mRNA and protein in NSCLC cells and tumours.

View Article and Find Full Text PDF

Malignant gliomas exhibit abnormal expression of proteolytic enzymes that may participate in the uncontrolled cell proliferation and aberrant interactions with the brain extracellular matrix. The multifunctional membrane bound serine aminopeptidase dipeptidyl peptidase (DPP)-IV has been linked to the development and progression of several malignancies, possibly both through the enzymatic and nonenzymatic mechanisms. In this report we demonstrate the expression of DPP-IV and homologous proteases fibroblast activation protein, DPP8 and DPP9 in primary cell cultures derived from high-grade gliomas, and show that the DPP-IV-like enzymatic activity is negatively associated with their in vitro growth.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

The granzyme B-induced cell death has been traditionally viewed as a primary mechanism that is used by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells to eliminate harmful target cells including allogeneic, virally infected and tumour cells. Granzyme B (GrB) is the most abundant serine protease which is stored in secretory granules of CTLs and NK cells. After recognition of the target cell, the engaged CTLs and NK cells vectorially secrete GrB along with other granule proteins including perforin into the immunological synapse.

View Article and Find Full Text PDF

Meningiomas are tumors derived from arachnoid cap cells that represent approximately 30% of all intracranial tumors. In this study, we investigated 22 human meningiomas for the expression of dipeptidyl peptidase (DPP)-IV activity and/or structure homologs (DASH), including canonical DPP-IV/CD26, fibroblast activation protein-alpha (FAPalpha), DPP8 and DPP9. DPP-IV-like enzymatic activity, including all enzymatically-active DASH molecules, was found in all 18 benign meningiomas WHO grade I and IV atypical meningiomas WHO grade II by continuous rate fluorimetric assay in tissue homogenates and catalytic enzyme histochemistry in situ.

View Article and Find Full Text PDF

Human proteinase inhibitor-9 (PI-9)/serpinB9 is an intracellular ovalbumin-family serpin with nucleocytoplasmic distribution which is expressed in certain normal cell types and cancer cells of different origin. Due to binding and inactivating of granzyme B (GrB), PI-9 can protect the cells from GrB-mediated apoptosis. High levels of PI-9 expression in certain cancer cells may contribute to their resistance against the immune mediated killing.

View Article and Find Full Text PDF

Members of the inhibitor of apoptosis protein (IAP) family, survivin and X-chromosome-linked IAP (XIAP), contribute to apoptosis resistance of cancer cells, and an increase in their expression may elevate the apoptotic threshold of malignant tumours during their growth and progression. In the present study, we investigated the expression status of survivin and its interactants hepatitis B X-interacting protein (HBXIP) and XIAP in non-small cell lung carcinoma (NSCLC) cell lines and NSCLC tumours and matched lungs from surgically treated patients in relation to their clinicopathological data. The expression of survivin, HBXIP and XIAP mRNAs was quantitated by real-time RT-PCR.

View Article and Find Full Text PDF

Alterations in dipeptidyl peptidase-IV (DPP-IV) enzymatic activity are characteristic of malignant transformation. Through its well-characterized functionality in regulating the activity of bioactive peptides by removal of the N-terminal dipeptide, DPP-IV activity may have profound effects upon metastatic potential and cell growth. Although DPP-IV/CD26 (EC 3.

View Article and Find Full Text PDF

Purpose: Tumour cells killing by cytotoxic therapies largely depends on triggering the intrinsic apoptosome-mediated caspase activation pathway but it had never been evaluated whether the expression of transcripts encoding the core components of apoptosome pathway is altered in non-small cell lung carcinoma (NSCLC).

Methods: We investigated the expression status of several apoptosome pathway-related transcripts including Apaf-1, procaspase-9, -3, -6, -7 and Smac in tumour and lung tissue samples from 65 surgically treated NSCLC patients and in 10 NSCLC cell lines with using real time RT-PCR.

Results: NSCLC tissues and cell lines showed significantly increased expression of procaspase-9, -3, -6 and Smac mRNAs as compared to the lungs and expression of these transcripts was simultaneously upregulated in a subset of NSCLCs belonging to different histopathological type, grade and stage categories.

View Article and Find Full Text PDF

Lung cancer is one of the most important avoidable causes of death around the world, it is the most widespread carcinoma with a very poor prognosis, and is the leading cause of cancer death in both developed and developing countries. At present more men than women die each year from lung cancer, but in recent years a rapid increase in lung cancer mortality has been observed among women in developed countries, contrasting with a levelling off or decrease among men. The rising trend in female lung cancer mortality has been observed to parallel with the past and current prevalence of cigarette smoking among women in the United States and elsewhere.

View Article and Find Full Text PDF

Purpose: The superiority of chemoradiotherapy (CRT) over radiation alone in locally advanced non-small cell lung cancer (NSCLC) has been proven, but the relative merits of a concurrent schedule versus their sequential administration are less clear. This study compared the safety and efficacy of concurrent and sequential CRT, with chemotherapy (CT) consisting of a cisplatin and vinorelbine regimen, in patients with locally advanced NSCLC.

Patients And Methods: One hundred and two previously untreated patients (aged 42-75 years) with locally advanced, stage IIIA (n = 15) or stage IIIB (n = 87) NSCLC were entered into the study.

View Article and Find Full Text PDF

The intrinsic apoptosis apparatus plays a significant role in generating and amplifying cell death signals. In this study we examined whether there are differences in the expression of its components and in its functioning in non-small cell lung carcinoma (NSCLC) and the lung. We show that NSCLC cell lines express Apaf-1 and procaspase-9 and -3 proteins and that the expression of Apaf-1 and procaspase-3, but not of procaspase-9 and -7, is frequently up-regulated in NSCLC tissues as compared to the lung.

View Article and Find Full Text PDF