In this two generation study with zebrafish (Danio rerio) we showed that exposure to 5-Fluorouracil (5FU), which is one of the most extensively used antineoplastic drugs in cancer therapy, induced histopathological changes in liver and kidney, DNA damage, micronuclei formation and upregulation of several DNA damage responsive genes and oncogenes (i.e., jun, myca) at concentrations relevant for environmental contamination. Although this chronic exposure to environmentally relevant concentrations of 5FU did not affect the reproduction of the exposed zebrafish, it cannot be excluded that 5FU can lead to degenerative changes, including cancers, which over longterm exposure of several generations might affect fish populations.
COBISS.SI-ID: 3417935
In this study we tested the toxicities of four anti-neoplastic drugs with different mechanisms of action (5-fluorouracil [5-FU], cisplatin [CDDP], etoposide [ET], and imatinib mesylate [IM]), and some of their binary mixtures, against two phytoplankton species: the alga Pseudokirchneriella subcapitata, and the cyanobacterium Synechococcus leopoliensis. These four drugs showed different toxic potential, and the two species examined also showed differences in their susceptibilities towards the tested drugs and their mixtures. The toxicities of the binary mixtures tested were predicted by the concepts of ‘concentration addition’ and ‘independent action’, and are compared to the experimentally determined toxicities. The data show that these mixtures can have compound-specific and species-specific synergistic or antagonistic effects, and they suggest that single compound toxicity data are not sufficient for the prediction of the aquatic toxicities of such anticancer drug mixtures.
COBISS.SI-ID: 3027791
In the study for the first time the influence of natural clay montmorillonite (CNa+), which is used in food packaging in order to give new materials and to improve polymer properties, on genomic stability and expression of genes involved in toxicity mechanisms was described in HepG2 cells. The results revealed that in HepG2 cells CNa+ increased the number of micronuclei and it deregulated many genes involved in the metabolism, immediate-early response/signaling, DNA damage response, oxidative stress and programmed cell death providing the evidence that CNa+is potentially genotoxic.
COBISS.SI-ID: 3645007
In the study a modification of ERCalux ® bioassay, which is used for testing of estrogenic activity of substances, was described. We successfully modified the assay (NE(ERCalux®) assay) for measuring estrogenic potential of environmental water samples without sample extraction. The results obtained were compared to chemical analysis (GC–MSD) and showed very good correlation between both methods.
COBISS.SI-ID: 2813007
In the present study, we generated metabolically active differentiated hepatic progenies (hDHP) from human adipose tissue derived mesenchymal stem cells (hASC) that can be used for genotoxicity testing. For this purpose, we applied s three-step hepatic differentiation procedure and obtained cells that express hepatic properties such as glycogen storage and albumin secretion. The results demonstrated high sensitivity of hDHP towards detection of DNA damage induced by indirect model genotoxic compounds, while non-differentiated hASC were insensitive. The gene and protein expression analysis confirmed the presence of key enzymes involved in metabolism of the three genotoxins (BaP, AFB1 and PhIP) in hDHP cells. Further, we successfully immortalized hDHP cells with hTERT transfection, resulting in a stable cell line with a great potential for the application in the routine genotoxicity testing.
COBISS.SI-ID: 4650575
In this study, we performed transcriptomic analysis of glioblastoma (GBM) tissues compared to normal brain tissues and revealed upregulation of CD9 gene, encoding for transmembrane protein tetraspanin, known to be involved in tumor progression. Using the public REMBRANDT database for brain tumors, we confirmed the prognostic value of CD9, whereby a more than two fold up-regulation correlates with shorter patient survival. We validated CD9 gene and protein expression showing selective up-regulation in GBM stem cells isolated from primary biopsies and in primary organotypic spheroids as well as in U87-MG and U373 GBM cell lines. In contrast, no or low CD9 gene expression was observed in normal human astrocytes, neural stem cells in normal brain tissues. CD9 silencing in three CD133+ GMB lines (NCH644, NCH421k and NCH660h) led to decreased cell proliferation, survival, invasion, and self-renewal ability, and altered expression of the stem-cell markers CD133, nestin and SOX2. Moreover, CD9-silenced GBM stem cells showed altered activation patterns of the Akt, MapK and Stat3 signaling transducers. Orthotopic xenotransplantation of CD9-silenced GBM stem cells into nude rats promoted prolonged survival. Therefore, the biomarker CD9 should be further evaluated as a target molecule for GBM treatment.
COBISS.SI-ID: 3660623
Proteases, including lysosomal cathepsins, are involved in many processes in cancer progression. Only recently, cathepsin K (CatK), originally reported as a collagenolytic protease produced by osteoclasts, appeared to be overexpressed as well in various types of cancers, including brain tumour glioma. In this review, the physiological functions of CatK are presented and compared to its potential role in pathobiolology of processes associated with tumour growth, invasion and metastasis of cancer cells and their interactions with the tumour microenvironment. CatK activity is either indirectly affecting signaling pathways, or directly degrading extracellular matrix (ECM) proteins. In glioma CatK possibly regulates cancer stem-like cell mobilisation out of their niches and modulates recently found physiological CatK substrates, including chemokines and growth factors. Finally, the application of CatK inhibitors, which are already in clinical trials for treatment of osteoporosis, has a potential to attenuate cancer aggressiveness.
COBISS.SI-ID: 3652943
We examined the U87, U251, and U373 glioblastoma (GBM) cell lines as in vitro models to determine the impact of cellular cross-talk on their phenotypic alterations in co-cultures. We were first to demonstrate the neural and mesenchymal molecular fingerprints of U87 and U373 cells, respectively. U87-cells were shown to lower the genomic stability of U373 (U251) cells, without affecting their proliferation, while oppositely, U87 cells showed increased genomic stability, decreased proliferation rates and increased invasion. Indirect and direct co-culturing of U87 and U373 cells showed mutually opposite effects on temozolomide resistance. By defining transcriptional alterations between various GBM cells we provided for better understanding of the mechanisms of glioblastoma heterogeneity, which shall provide the basis for more informed glioma treatment in the future.
COBISS.SI-ID: 3643471
Several groups, including ours, have published results showing spontaneous transformation of human mesenchymal stem cells (MSC). Recently, we reported in this journal spontaneous transformation of bone marrow-derived human MSC (hMSC), isolated and expanded independently in two laboratories (1). Inspired by the recent focus on misidentification of cell lines in which cell culture repositories indicate that between 18 to 36% of the cell lines contain misidentified species, we did DNA fingerprinting and/or short tandem repeat (STR) analysis comparing the normal MSC with their transformed counterparts. The analysis shows that the transformed mesenchymal stem cells (TMC) in one laboratory were cross-contaminated with human fibrosarcoma or osteosarcoma cell lines, whereas in the other laboratory cross-contamination was due to two glioma cell lines. Our observations underscore the need for extremely stringent cell culture procedures when it comes to the use of primary cell cultures, including MSC, for therapeutic purposes. Further, our results highlight the need for cell line verification prior to scientific publishing.
COBISS.SI-ID: 2266703
Glioblastoma multiforme are an aggressive form of brain tumors that are characterized by distinct invasion of single glioblastoma cells, which infiltrate the brain parenchyma. This appears to be stimulated by the communication between cancer and stromal cells. Mesenchymal stem cells (MSCs) are part of the glioblastoma microenvironment, and their ‘crosstalk’ with glioblastoma cells is still poorly understood. This is the first demonstration of glioblastoma cell-type-specific responses to MSCs in direct glioblastoma co-cultures, where MSCs inhibited the invasion of U87 cells and enhanced the invasion of U373. MSC-enhanced invasion of U373 cells was assisted by overexpression of selected roteases. In contrast, these proteases had no effect on U87 cell invasion under MSC coculturing. Finally, we identified differentially expressed genes, in U87 and U373 cells that could explain different response of these cell lines to MSCs. In conclusion, we demonstrated that MSC/glioblastoma cross-talk is different in the two glioblastoma cell phenotypes, which contributes to tumor heterogeneity.
COBISS.SI-ID: 4238415