Репозиторий Университета

© 2020 Epithelial-to-mesenchymal transition (EMT) is an essential molecular and cellular process that is part of normal embryogenesis and wound healing, and also has a ubiquitous role in various types of carcinoma and glioblastoma. EMT is activated and regulated by specific microenvironmental endogenous triggers and a complex network of signalling pathways. These mostly include epigenetic events that affect protein translation-controlling factors and proteases, altogether orchestrated by the switching on and off of oncogenes and tumour-suppressor genes in cancer cells. The hallmark of cancer-linked EMT is that the process is incomplete, as it is opposed by the reverse process of mesenchymal-to-epithelial transition, which results in a hybrid epithelial/mesenchymal phenotype that shows notable cell plasticity. This is a characteristic of cancer stem cells (CSCs), and it is of the utmost importance in their niche microenvironment, where it governs CSC migratory and invasive properties, thereby creating metastatic CSCs. These cells have high resistance to therapeutic treatments, in particular in glioblastoma.

© 2019 John Wiley  &  Sons Ltd Recent studies highlighted the role of autophagy as a cardinal regulatory system for homeostasis and cancer-related signalling pathways. In this context, the deregulated expression of p62 – Sequestosome1 (p62/SQSTM1) – a protein acting both as an autophagy receptor and signalling hub, has been associated with tumour development and chronic inflammation. Multiple clinical studies test drugs targeting autophagy, and even more research is on the way to clinical trials. However, no comparative investigations have been carried out to identify adequate preclinical models to assess p62-based medicine. In veterinary oncology the role of p62 in cancer-related pathways has been largely ignored. We compared p62 sequences in multiple organisms and found that canine p62 significantly diverges from the humans and from other animals sequences. Then, we chart by immunohistochemistry the expression levels of p62 in canine mammary tumours. A total of 66 tumours and 10 non-neoplastic mammary samples were examined. The expression of p62 was higher in normal tissue and adenomas than carcinomas, with lowest levels of p62 protein detected in high grade carcinomas. In all cases examined the tumour stroma appeared to be p62-negative. Taken together our results would suggest that in dogs the association between p62 expression and cancer cells overturns that reported in human breast carcinoma, where p62 accumulates in malignant cells as compared to normal epithelium. Thus, at least in canine mammary tumours, p62 should be not considered a tumour-rejection antigen for an anti-cancer immunotherapy.

©2018 by the authors. Licensee MDPI, Basel, Switzerland. Engineering of a “smart” drug delivery system to specifically target tumour cells has been at the forefront of cancer research, having been engineered for safer, more efficient and effective use of chemotherapy for the treatment of cancer. However, selective targeting and choosing the right cancer surface biomarker are critical for a targeted treatment to work. Currently, the available delivery systems use a two-dimensional monolayer of cancer cells to test the efficacy of the drug delivery system, but designing a “smart” drug delivery system to be specific for a tumour in vivo and to penetrate the inner core remains a major design challenge. These challenges can be overcome by using a study model that integrates the three-dimensional aspect of a tumour in a culture system. Here, we tested the efficacy of a functionalized folic acid-conjugated amphiphilic alternating copolymer poly(styrene-alt-maleic anhydride) (FA-DABA-SMA) via a biodegradable linker 2,4-diaminobutyric acid (DABA) to specifically target and penetrate the inner core of three-dimensional avascular human pancreatic and breast tumour spheroids in culture. The copolymer was quantitatively analyzed for its hydrophobic drug encapsulation efficiency using three different chemical drug structures with different molecular weights. Their release profiles and tumour targeting properties at various concentrations and pH environments were also characterized. Using the anticancer drug curcumin and two standard clinical chemotherapeutic hydrophobic drugs, paclitaxel and 5-fluorouracil, we tested the ability of FA-DABA-SMA nanoparticles to encapsulate the differently sized drugs and deliver them to kill monolayer pancreatic cancer cells using the WST-1 cell proliferation assay. The findings of this study revealed that the functionalized folic acid-conjugated amphiphilic alternating copolymer shows unique properties as an active “smart” tumor-targeting drug delivery system with the ability to internalize hydrophobic drugs and release the chemotherapeutics for effective killing of cancer cells. The novelty of the study is the first to demonstrate a functionalized “smart” drug delivery system encapsulated with a hydrophobic drug effectively targeting and penetrating the inner core of pancreatic and breast cancer spheroids and reducing their volumes in a dose-and time-dependent manner.

© 2018 Publishing House of the Union of Pediatricians. All rights reserved. Background. Solid tumors in children are one of the most common childhood malignancy, second only to hemoblastosis. Among solid tumours, about 5% are bone sarcomas: osteosarcoma (3%) and Ewing's sarcoma (2%). Atypicality of the these diseases course makes an early diagnosis a real challenge. Case Reports. The article presents six clinical observations of patients with bone sarcomas. We demonstrate the difficulties in diagnosing of this disease group which is associated with the absence of both specific symptoms and distinct clinical picture. Conclusion. Pediatricians and pediatric surgeons should take into account the possibility of atypical course of bone sarcomas in children. Low cancer alertness is the reason for a significant delay in establishing the correct diagnosis which contributes to the tumour process generalization and reduces the chances of achieving remission while increasing the cost of treating such patients.

© 2018 Bentham Science Publishers. Gastrointestinal stromal tumours are the most common mesenchymal tumours of the gastrointestinal tract. Despite similar mutation pattern of activating mutations in KIT or PDGFRA receptors in 85% of cases, they demonstrate significantly heterogeneous clinical behaviour and pathological characteristics. This heterogeneity opens the question of the role of other factors and mechanisms of regulation in the development of GIST. Additional mutations in downstream effectors of GIST related signalling pathways or aberrant expression of non-coding RNAs may be additional contributing factors, the latter being increasingly recognized in carcinogenesis in general. Recently, a substantial progress has been achieved in understanding the functional roles of lncRNAs in GIST suggesting their potential employment as biomarkers and therapeutic targets in GIST. Moreover, some miRNAs have recently been found to be able to sensitize cells to imatinib, which could be an attractive option to overcome the resistance to the drug, which hampers the efficacy of GIST treatment. Therefore, the advantage can be taken of both coding and non-coding parts of the genome in order to significantly improve prognostication and help find personalized therapy for patients, depending on a subtype of GIST and personal characteristics.