Glioblastoma (GBM), as the most aggressive brain tumor, displays a high expression of Src tyrosine kinase, which is involved in the survival, migration, and invasiveness of tumor cells. Thus, Src emerged as a potential target for GBM therapy. The effects of Src inhibitors pyrazolo[3,4-d]pyrimidines, Si306 and its prodrug pro-Si306 were investigated in human GBM cell lines (U87 and U87-TxR) and three primary GBM cell cultures. Primary GBM cells were more resistant to Si306 and pro-Si306 according to the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. However, the ability of all GBM cells to degrade the extracellular matrix was considerably compromised after Si306 and pro-Si306 applications. Besides reducing the phosphorylation of Src and its downstream signaling pathway components, both compounds decreased the phosphorylated form of focal adhesion kinase (FAK) and epidermal growth factor receptor (EGFR) expression, showing the potential to suppress the aggressiveness of GBM. In vivo, Si306 and pro-Si306 displayed an anti-invasive effect against U87 xenografts in the zebrafish embryo model. Considering that Si306 and pro-Si306 are able to cross the blood–brain barrier and suppress the spread of GBM cells, we anticipate their clinical testing in the near future. Moreover, the prodrug showed similar efficacy to the drug, implying the rationality of its use in clinical settings.

Cancer drug resistance and poor selectivity towards cancer cells demand the constant search for new therapeutics. PI3K-Akt-mTOR and RAS-MAPK-ERK signaling pathways are key mechanisms involved in cell survival, proliferation, differentiation, and metabolism and their deregulation in cancer can promote development of therapy resistance. We investigated the effects of targeted inhibitors (wortmannin, GSK690693, AZD2014 and tipifarnib) towards these two pathways on early zebrafish and sea urchin development to assess their toxicity in normal, fast proliferating cells. PI3K inhibitor wortmannin and RAS inhibitor tipifarnib displayed highest toxicity while GSK690693, a pan-Akt kinase inhibitor, exhibited a less significant impact on embryo survival and development. Moreover, inhibition of the upstream part of the PI3K-Akt-mTOR pathway (wortmannin/GSK690693 co-treatment) produced a synergistic effect and impacted zebrafish embryo survival and development at much lower concentrations. Dual mTORC1/mTORC2 inhibitor...

Tussilago farfara (coltsfoot) and Verbascum thapsus (mullein) have been used as folk remedies for treating respiratory disorders. The aim of this study was to test the toxicity of the water extracts of T. farfara and V. thapsus in vivo in zebrafish and in vitro in BEAS 2B epithelial bronchial cells. To the best of our knowledge, this is the first study to investigate the antioxidative properties of T. farfara and V. thapsus extracts in cell culture. Our results show that the T. farfara leaf extract does not produce toxic effects on zebrafish embryos or BEAS 2B cells, and that it has a protective effect in BEAS 2B after induction of oxidative stress. The water extract from V. thapsus displayed pronounced toxic effects on zebrafish embryos and BEAS 2B cells and did not exhibit a significant antioxidative effect on BEAS 2B cells exposed to oxidative stress. Our results suggest that the use of T. farfara water leaf extract is potentially safe and effective in treating respiratory disorders, whereas the use of V. thapsus needs further investigation. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON173008]

Background: High heterogeneity levels of cystic fibrosis transmembrane regulator (CFTR) are manifested in different populations. The aim of this study was to analyze comprehensively all mutations in the CFTR gene in Serbian patients with cystic fibrosis (CF) and to use the findings to propose a testing algorithm for the Serbian population. Materials and Methods: Cascade screening was employed to detect mutations in the CFTR gene of 90 patients suspected of having CF, using polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism or PCR-mediated site directed mutagenesis, Sanger sequencing, and/or next-generation sequencing. Results: This is the first report for the Serbian CF population where single nucleotide polymorphisms, small insertions and deletions, large genome rearrangements, and copy number variants were analyzed in detail. A high degree of heterogeneity within the CFTR was documented among our cohort of 90 patients. We identified 19 CF-causing mutations and 3 with varying consequences, including a previously unreported deletion of the entire exon 11. Conclusion: Considering the spectrum and frequency of mutations found, we recommend a multistep sequencing algorithm in combination with evaluation of large rearrangements for future analyses of the CFTR gene in the Serbian population.

Tunneling nanotubes (TNTs) are transient actin-based structures that allow direct communication between distant cells. TNTs are found in many cell types and serve as a mode of transport of various cellular components including organelles such as mitochondria, autophagosomes and endosome but also pathogens such as protein aggregates and viruses and therefore have diverse functions, both physiological and pathological. We aimed to test the effect of electronic cigarette liquids (ECL) on cell-cell communication and formation of TNTs in human bronchial epithelial cell line BEAS2B. We used commercialy available ECL with and without nicotine at concentration previosly shown not to affect cell survival. The number of TNTs was quantified at 4h, 24h and 48h. ECL treatment induced increase in formation of tunneling nanotubes starting from 4h and continuing for the duration of the treatment, independent of nicotine composition. TNTs can be induced under various stress conditions to facilitate homeostasis and surpass stress and we showed that both ECLs induced oxidative stress in BEAS2B cells, which could be potential trigger for the formation of TNTs. We hypothesized that TNTs might promote mitochondrial transfer to ECL exposed cells thus mitigating effects of oxidative stress, however, confocal imaging did not reveal significant difference in mitochondria transfer between co-culture of treated and untreated cells compared to co-culture of untreated cells. It is possible that other molecules and organelles are transported under these conditions which remains to be determined as well as the physiological significance of TNT formation under these conditions.