1. On G-Drazin partial order in ringsGregor Dolinar, Bojan Kuzma, Janko Marovt, Dijana Mosić, 2024, original scientific article Abstract: We extend the concept of a G-Drazin inverse from the set $M_n$ of all $n \times n$ complex matrices to the set ${\cal R}^D$ of all Drazin invertible elements in a ring ${\cal R}$ with identity. We also generalize a partial order induced by G-Drazin inverses from $M_n$ to the set of all regular elements in ${\cal R}^D$, study its properties, compare it to known partial orders, and generalize some known results.
Keywords: Drazin inverse, core-nilpotent decomposition, partial order, annihilator, ring
Published in DiRROS: 05.09.2024; Views: 98; Downloads: 57
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2. Kmetijstvo in biodiverziteta z roko v rokiMojca Pibernik, Blaž Koderman, Danilo Bevk, Aleš Tolar, Janko Rode, 2019, other monographs and other completed works Abstract: Biodiverziteta je vse živo
Biodiverziteta (biotska pestrost) je pestrost življenja na Zemlji od bakterij in gliv do rastlin in živali. Nastala je v milijardah let razvoja življenja. Pomembna značilnost biodiverzitete je izjemna povezanost organizmov, ki sami ne bi mogli preživeti, skupaj pa sestavljajo edinstven preplet, ki odločilno vpliva na razmere na našem planetu.
Keywords: kmetijstvo, biodiverziteta
Published in DiRROS: 04.09.2024; Views: 110; Downloads: 72
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3. Addition of 2-(ethylamino)acetonitrile group to nitroxoline results in significantly improved anti-tumor activity in vitro and in vivoAna Mitrović, Izidor Sosič, Špela Kos, Urša Lampreht Tratar, Barbara Breznik, Simona Kranjc Brezar, Bojana Mirković, Stanislav Gobec, Tamara Lah Turnšek, Maja Čemažar, Gregor Serša, Janko Kos, 2017, original scientific article Abstract: Lysosomal cysteine peptidase cathepsin B, involved in multiple processes associated with tumor progression, is validated as a target for anti-cancer therapy. Nitroxoline, a known antimicrobial agent, is a potent and selective inhibitor of cathepsin B, hence reducing tumor progression in vitro and in vivo. In order to further improve its anti-cancer properties we developed a number of derivatives using structure-based chemical synthesis. Of these, the 7-aminomethylated derivative (compound 17) exhibited significantly improved kinetic properties over nitroxoline, inhibiting cathepsin B endopeptidase activity selectively. In the present study, we have evaluated its anti-cancer properties. It was more effective than nitroxoline in reducing tumor cell invasion and migration, as determined in vitro on two-dimensional cell models and tumor spheroids, under either endpoint or real time conditions. Moreover, it exhibited improved action over nitroxoline in impairing tumor growth in vivo in LPB mouse fibrosarcoma tumors in C57Bl/6 mice. Taken together, the addition of a 2-(ethylamino)acetonitrile group to nitroxoline at position 7 significantly improves its pharmacological characteristics and its potential for use as an anti-cancer drug.
Keywords: nitroxoline derivative, cathepsin B, inhibition, tumor invasion, cell migration
Published in DiRROS: 26.07.2024; Views: 215; Downloads: 178
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4. Localization patterns of cathepsins K and X and their predictive value in glioblastomaBarbara Breznik, Clara Limbaeck Stanic, Andrej Porčnik, Andrej Blejec, Miha Koprivnikar Krajnc, Roman Bošnjak, Janko Kos, Cornelis J. F. van Noorden, Tamara Lah Turnšek, 2018, original scientific article Abstract: Background
Glioblastoma is a highly aggressive central nervous system neoplasm characterized by extensive infiltration of malignant cells into brain parenchyma, thus preventing complete tumor eradication. Cysteine cathepsins B, S, L and K are involved in cancer progression and are overexpressed in glioblastoma. We report here for the first time that cathepsin X mRNA and protein are also abundantly present in malignant glioma.
Materials and methods
Gene expression of cathepsins K and X was analyzed using publically-available tran-scriptomic datasets and correlated with glioma grade and glioblastoma subtype. Kaplan-Maier survival analysis was performed to evaluate the predictive value of cathepsin K and X mRNA expression. Cathepsin protein expression was localized and semi-quantified in tumor tissues by immunohistochemistry.
Results
Highest gene expression of cathepsins K and X was found in glioblastoma, in particular in the mesenchymal subtype. Overall, high mRNA expression of cathepsin X, but not that of cathepsin K, correlated with poor patients’ survival. Cathepsin K and X proteins were abundantly and heterogeneously expressed in glioblastoma tissue. Immuno-labeling of cathepsins K and X was observed in areas of CD133-positive glioblastoma stem cells, localized around arterioles in their niches that also expressed SDF-1α and CD68. mRNA levels of both cathepsins K and X correlated with mRNA levels of markers of glioblastoma stem cells and their niches.
Conclusions
The presence of both cathepsins in glioblastoma stem cell niche regions indicates their possible role in regulation of glioblastoma stem cell homing in their niches. The clinical relevance of this data needs to be elaborated in further prospective studies.
Keywords: cathepsins, glioblastoma, immunohistochemistry, patient survival, cancer stem cell niches
Published in DiRROS: 24.07.2024; Views: 250; Downloads: 178
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5. Cysteine cathepsins B, X and K expression in peri-arteriolar glioblastoma stem cell nichesBarbara Breznik, Clara Limbaeck Stanic, Janko Kos, Mohammed Khurshed, Vashendriya V. V. Hira, Roman Bošnjak, Tamara Lah Turnšek, Cornelis J. F. van Noorden, 2018, original scientific article Abstract: Glioblastoma (GBM) is the most lethal brain tumor also due to malignant and therapy-resistant GBM stem cells (GSCs) that are localized in protecting hypoxic GSC niches. Some members of the cysteine cathepsin family of proteases have been found to be upregulated in GBM. Cathepsin K gene expression is highly elevated in GBM tissue versus normal brain and it has been suggested to regulate GSC migration out of the niches. Here, we investigated the cellular distribution of cathepsins B, X and K in GBM tissue and whether these cathepsins are co-localized in GSC niches. Therefore, we determined expression of these cathepsins in serial paraffin sections of 14 human GBM samples and serial cryostat sections of two samples using immunohistochemistry and metabolic mapping of cathepsin activity using selective fluorogenic substrates. We detected cathepsins B, X and K in peri-arteriolar GSC niches in 9 out of 16 GBM samples, which were defined by co-expression of the GSC marker CD133, the niche marker stromal-derived factor-1α (SDF-1α) and smooth muscle actin as a marker for arterioles. The expression of cathepsin B and X was detected in stromal cells and cancer cells throughout the GBM sections, whereas cathepsin K expression was more restricted to arteriole-rich regions in the GBM sections. Metabolic mapping showed that cathepsin B, but not cathepsin K is active in GSC niches. On the basis of these findings, it is concluded that cathepsins B, X and K have distinct functions in GBM and that cathepsin K is the most likely GSC niche-related cathepsin of the three cathepsins investigated.
Keywords: cysteine cathepsins, glioblastoma stem cells, niches, stroma, proteolytic activity
Published in DiRROS: 24.07.2024; Views: 225; Downloads: 167
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7. Upregulation of cathepsin X in glioblastoma : interplay with γ-enolase and the effects of selective cathepsin X inhibitorsBernarda Majc, Anamarija Habič, Metka Novak, Ana Rotter, Andrej Porčnik, Jernej Mlakar, Vera Župunski, Urša Pečar Fonović, Damijan Knez, Nace Zidar, Stanislav Gobec, Janko Kos, Tamara Lah Turnšek, Anja Pišlar, Barbara Breznik, 2022, original scientific article Keywords: glioblastoma, cathepsin X, γ-enolase, tumor microenvironment, glioblastoma stem cells, cathepsin X inhibitors
Published in DiRROS: 16.07.2024; Views: 213; Downloads: 162
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9. DNA barcoding insufficiently identifies European wild bees (Hymenoptera, Anthophila) due to undefined species diversity, genus-specific barcoding gaps and database errorsJanko Šet, Rok Šturm, Blaž Koderman, Danilo Bevk, Andrej Gogala, Denis Kutnjak, Klemen Čandek, Matjaž Gregorič, 2024, original scientific article Keywords: insect pollinators, wild bees, DNA, biodiversity, databases
Published in DiRROS: 19.06.2024; Views: 291; Downloads: 152
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10. Localization patterns of cathepsins K and X and their predictive value in glioblastomaBarbara Breznik, Clara Limbaeck Stanic, Andrej Porčnik, Andrej Blejec, Miha Koprivnikar Krajnc, Roman Bošnjak, Janko Kos, Cornelis J. F. van Noorden, Tamara Lah Turnšek, 2018, original scientific article Keywords: cathepsins, glioblastoma, immunohistochemistry, patient survival, cancer stem cell niches
Published in DiRROS: 11.06.2024; Views: 193; Downloads: 142
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