Cytoplasmic mislocalization and aggregation of nuclear RNA binding proteins are of the hallmark pathological features of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) and suggests perturbance of nuclear transport mechanisms in their aetiology. In 95% of all ALS and 60% of FTLD patients the aggregating protein is TDP-43, thus defining the major part of the disease spectrum as TDP-43 proteinopathies. Compromised nucleocytoplasmic shuttling has recently also been associated with a hexanucleotide repeat expansion mutation in C9orf72, which is the most common genetic cause of ALS and FTLD, and leads to accumulation of cytoplasmic TDP-43 inclusions. Mutation in C9orf72 may disrupt nucleocytoplasmic shuttling on the level of C9ORF72 protein, the transcribed hexanucleotide repeat RNA, and/or dipeptide repeat proteins translated form the hexanucleotide repeat RNA. These defects of nucleocytoplasmic shuttling may therefore, constitute the common ground of the underlying disease mechanisms in different molecular subtypes of ALS and FTLD.
COBISS.SI-ID: 29663527
Cystatin F has been suggested to regulate the cytotoxicity of NK cells by inhibiting the major granzyme convertases, cathepsins C and H. To test this hypothesis, we prepared variants of cystatin F and analyzed their uptake, subcellular trafficking, peptidase inhibition, and the impact on the cytotoxicity of NK-92 cells and primary NK cells. We found that the glycosylation pattern is responsible for the secretion, uptake, and subcellular sorting of cystatin F. Active, N-terminally truncated, monomeric cystatin F can also be internalized by recipient cells and targeted to endo/lysosomes, affecting also cells lacking the activating peptidase. Cystatin F mutants capable of cell internalization and trafficking through the endo/lysosomal pathway significantly decreased cathepsin C and H activities, both in situ, following transfection and in trans, using conditioned media. Further, incubation of IL-2 stimulated NK-92 and primary NK cells with full-length and N-terminally truncated cystatin F mutants led to suppression of their granule-mediated cytotoxicity.
COBISS.SI-ID: 30930471
Lectins have been recognized as promising carrier molecules for targeted drug delivery. We tested fungal lectin MpL as potential cystatin delivery carrier. MpL is endocytosed in a clathrin-dependent manner and accumulates initially in the Golgi apparatus and, finally, in the lysosomes. We constructed fusion protein consisting of MpL and the cysteine peptidase inhibitors cystatin C. It impaired both the intracellular degradation of extracellular matrix and the invasiveness of cancer cells due to cystatin's intracellular function. MpL thus enable protein drugs to enter cancer cells, enhance their internalization and sort them to lysosomes and the Golgi apparatus.
COBISS.SI-ID: 30318887
Cathepsin X is a cysteine peptidase involved in the progression of cancer and neurodegenerative diseases. In this study triazole-based reversible and selective inhibitors of cathepsin X have been identified. Of a series of selected triazole-benzodioxine derivatives, compound 22 is the most potent inhibitor of cathepsin X carboxypeptidase activity (Ki 2.45microM) with at least 100-fold greater selectivity in comparison to cathepsin B or other related cysteine peptidases. Compound 22 significantly inhibits the migration of tumor cells and increases the outgrowth of neurites, both processes being under the control of cathepsin X carboxypeptidase activity.
COBISS.SI-ID: 4382065
Cathepsin B 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. 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. Moreover, it exhibited improved action over nitroxoline in impairing tumor growth in vivo in LPB mouse fibrosarcoma tumors in C57Bl/6 mice.
COBISS.SI-ID: 4360305