1. Transmembrane protein CD9 is glioblastoma biomarker, relevant for maintenance of glioblastoma stem cellsNeža Podergajs, Helena Motaln, Uroš Rajčević, Urška Verbovšek, Marjan Koršič, Nina Obad, Heidi Espedal, Miloš Vittori, Christel Herold-Mende, Hrvoje Miletic, Rolf Bjerkvig, Tamara Lah Turnšek, 2016, original scientific article Abstract: The cancer stem cell model suggests that glioblastomas contain a subpopulation of stem-like tumor cells that reproduce themselves to sustain tumor growth. Targeting these cells thus represents a novel treatment strategy and therefore more specific markers that characterize glioblastoma stem cells need to be identified. In the present study, we performed transcriptomic analysis of glioblastoma tissues compared to normal brain tissues revealing sensible up-regulation of CD9 gene. CD9 encodes the transmembrane protein tetraspanin which is involved in tumor cell invasion, apoptosis and resistance to chemotherapy. 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 glioblastoma stem cells isolated from primary biopsies and in primary organotypic glioblastoma spheroids as well as in U87-MG and U373 glioblastoma cell lines. In contrast, no or low CD9 gene expression was observed in normal human astrocytes, normal brain tissue and neural stem cells. CD9 silencing in three CD133+ glioblastoma cell 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 glioblastoma stem cells showed altered activation patterns of the Akt, MapK and Stat3 signaling transducers. Orthotopic xenotransplantation of CD9-silenced glioblastoma stem cells into nude rats promoted prolonged survival. Therefore, CD9 should be further evaluated as a target for glioblastoma treatment.
Keywords: biomarker, CD9, glioblastoma stem cells, neural stem cells, tetraspanin
Published in DiRROS: 26.07.2024; Views: 110; Downloads: 83
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2. Expansive growth of two glioblastoma stem-like cell lines is mediated by bFGF and not by EGFNeža Podergajs, Narve Brekka, Bernhard Radlwimmer, Christel Herold-Mende, Krishna M. Talasila, Katja Tiemann, Uroš Rajčević, Tamara Lah Turnšek, Rolf Bjerkvig, Hrvoje Miletic, 2013, published scientific conference contribution Abstract: Background. Patient-derived glioblastoma (GBM) stem-like cells (GSCs) represent a valuable model for basic and therapeutic research. GSCs are usually propagated in serum-free Neural Basal medium supplemented with bFGF and EGF. Yet, the exact influence of these growth factors on GSCs is still unclear. Recently it was suggested that GBM stemlike cells with amplified EGFR should be cultured in stem cell medium without EGF, as the presence of EGF induced rapid loss of EGFR amplification. However, patient biopsies are usually taken into culture before their genomic profiles are defined. Thus, an important question remains whether GBM cells without EGFR amplification also can be cultured in stem cell medium without EGF.Meterials and methods. To address this question, we used two heterogeneous glioblastoma GSC lines (NCH421k and NCH644) that lack EGFR amplification.Results. Although both cell lines showed very low EGFR expression under standard growth conditions, bFGF stimulation induced higher expression of EGFR in NCH644. In both cell lines, expression of the stem cell markers nestin and CD133 was higher upon stimulation with bFGF compared to EGF. Importantly, bFGF stimulated the growth of both cell lines, whereas EGF had no effect. We verified that the growth stimulation by bFGF was either mediated by proliferation (NCH421k) or resistance to apoptosis (NCH644).Conclusions. We demonstrate that GSC cultures without EGFR amplification can be maintained and expanded with bFGF, while the addition of EGF has no significant effect and therefore can be omitted.
Keywords: glioblastoma, stem cell cultures, bFGF
Published in DiRROS: 03.04.2024; Views: 244; Downloads: 107
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3. Development and characterization of a novel mAb against bilitranslocase - a new biomarker of renal carcinomaSendi Montanič, Michela Terdoslavich, Uroš Rajčević, Luigina De Leo, Serena Bonin, Vladka Čurin-Šerbec, Sabina Passamonti, 2013, original scientific article Keywords: bilitranslocase, monoclonal antibody, peptide antigen
Published in DiRROS: 22.03.2024; Views: 243; Downloads: 67
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4. Assessment of differential expression of oncogenes in adenocarcinoma of stomach with fluorescent labeling and simultaneous amplification of gene transcriptsUroš Rajčević, Petra Hudler, Gordan Mijovski, Gregor Gorjanc, Georg Hölzl, Stanislav Repše, Robert Juvan, Milena Kovač, Christian G. Huber, Radovan Komel, 2007, original scientific article Abstract: Background. Gastric cancer is one of the leading malignancies with a poor prognosis and low survival rates. Although the mechanisms underlying its development are still unknown, there is a consensus that genetic instability, inactivation of tumor suppressor genes and over-expression of oncogenes are involved in the early and late stages of gastric carcinogenesis. In the present study we wanted to display differential expression of seven oncogenes,namely CCNE1, EGF, ERBB3, FGF4, HRG1, HGFR and TDGF1. Patients and methods. We employed a method based on the multiplex reverse transcription polymerase chain (RT-PCR) method with a fluorescence detection. Results. More than half of patients (74.3%) out of total 74 with gastric adenocarcinoma had over-expressed at least one oncogene, with the exception of FGF4, which was expressed in tumor tissue of less than one third of patients. 56.8% of the patients patients showed over-expression of two or more oncogenes. Conclusions. Patients with precancerous lesions had elevated levels of TDGF1 or cripto-1 (64.9%) and CCNE1 (57.1%), suggesting that they could be used as markers for an early detection of malignant changes in stomach. Finally, the fluorescent multiplex RT-PCR method could be of value for rapid assessment of oncogene mRNA levels in small samples of tumor or precancerous biopsies.
Published in DiRROS: 20.02.2024; Views: 310; Downloads: 86
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