Surface Modification of Additively Fabricated Titanium-Based Implants by Means of Bioactive Micro-Arc Oxidation Coatings for Bone Replacement.

In this work, the micro-arc oxidation method is used to fabricate surface-modified complex-structured titanium implant coatings to improve biocompatibility. Depending on the utilized electrolyte solution and micro-arc oxidation process parameters, three different types of coatings (one of them-oxide, another two-calcium phosphates) were obtained, differing in their coating thickness, crystallite phase composition and, thus, with a significantly different biocompatibility. An analytical approach based on X-ray computed tomography utilizing software-aided coating recognition is employed in this work to reveal their structural uniformity. Electrochemical studies prove that the coatings exhibit varying levels of corrosion protection. In vitro and in vivo experiments of the three different micro-arc oxidation coatings prove high biocompatibility towards adult stem cells (investigation of cell adhesion, proliferation and osteogenic differentiation), as well as in vivo biocompatibility (including histological analysis). These results demonstrate superior biological properties compared to unmodified titanium surfaces. The ratio of calcium and phosphorus in coatings, as well as their phase composition, have a great influence on the biological response of the coatings.

Nanoparticles in Gastric Cancer Management.

Gastric cancer is the second most common cause of cancer-related deaths in the world. The surgical management of the tumor is the best therapeutic option for gastric cancer patients. A combination of a heterogeneous distribution of genetic and environmental factors appears to be required to explain patients' poor prognosis. A search for targeted and molecular-based approaches is affected by the optimal gastric cancer drug management. The modern multidisciplinary approach to treating the pathology used worldwide prolongs the overall patient survival and decreases the rate of recurrence. An understanding of the mechanisms that underlie therapies will provide new insights into gastric cancer treatment. The improvement in medicine will probably be associated with a study of tumor biology, followed by a personalized and molecular-based approach development in anticancer drugs administration. The modern perspective in gastric cancer detection and treatment is the application of nanoparticles. Nanoparticles affecting the intensity of biological processes in cancer cells can be used to treat cancers to increase the effectiveness of anti-tumor therapy. Their cytotoxicity involves a wide range of pathological events. Their targets are the extracellular matrix degradation, epithelial-mesenchymal transition, tumor angiogenesis, tumor microenvironment modulation. These are accompanied by lipid peroxidation, apoptosis, and autophagic flux. Preliminary studies on the efficacy of the use of nanoparticles in cultured gastric cancers open new opportunities for anti-tumor treatment to overcome the toxicity of therapeutic agents and decrease the rate of resistance to anticancer drugs and therapies.

Molecular Mechanism of Resistance to Chemotherapy in Gastric Cancers, the Role of Autophagy.

Gastric cancer (GC) is biologically and genetically heterogeneous with complex carcinogenesis at the molecular level. Despite the application of multiple approaches in the GC treatment, its 5-year survival is poor. A major limitation of anti-cancer drugs application is intrinsic or acquired resistance, especially to chemotherapeutical agents. It is known that the effectiveness of chemotherapy remains debatable and varies according to the molecular type of GC. Chemotherapy has an established role in the management of GC. Perioperative chemotherapy or postoperative chemotherapy is applied for localized ones. Most of the advanced GC patients have a poor response to treatment and unfavorable outcomes with standard therapies. Resistance substantially limits the depth and duration of clinical responses to targeted anticancer therapies. Through the use of complementary experimental approaches, investigators have revealed that cancer cells can achieve resistance through adaptation or selection driven by specific genetic, epigenetic, or microenvironmental alterations. Ultimately, these diverse alterations often lead to the activation of MAPK, AKT/mTOR, and Wnt/ß-catenin signaling pathways that, when co-opted, enable cancer cells to survive drug treatments. We have summarized the mechanisms of resistance development to cisplatin, 5-fluorouracil, and multidrug resistance in the GC management. The complexity of molecular targets and components of signaling cascades altered in the resistance development results in the absence of significant benefits in GC treatment, and its efficacy remains low. The universal process responsible for the failure in the multimodal approach in GC treatment is autophagy. Its dual role in oncogenesis is the most unexplored issue. We have discussed the possible mechanism of autophagy regulation upon the action of endogenous factors and drugs. The experimental data obtained in the cultured GC cells need further verification. To overcome the cancer resistance and to prevent autophagy as the main reason of ineffective treatment, it is suggested the concept of the direct influence of autophagy molecular markers followed by the standard chemotherapy. Dozen of studies have focused on finding the rationale for the benefits of such complex therapy. The perspectives in the molecular-based management of GC are associated with the development of molecular markers predicting the protective autophagy initiation and search for novel targets of effective anticancer therapy.

Heterogeneity of Circulating Tumor Cells in Neoadjuvant Chemotherapy of Breast Cancer.

The biological properties of circulating tumor cells (CTCs), and their dynamics during neoadjuvant chemotherapy are important, both for disease progression prediction and therapeutic target determination, with the aim of preventing disease progression. The aim of our study was to estimate of different CTC subsets in breast cancer during the NACT (neoadjuvant chemotherapy). The prospective study includes 27 patients with invasive breast cancer, T2-4N0-3M0, aged 32 to 60 years. Venous heparinized blood samples, taken before and after biopsy, after each courses of chemotherapy (on days 3-7), and before surgical intervention, served as the material for this study. Different subsets of circulating tumor cells were determined on the basis of the expression of EpCAM, CD45, CD44, CD24, and N-Cadherin using flow cytometry. As the result of this study, it has been observed that significant changes in the quantity of the different subsets of circulating tumor cells in patients' blood were observed after carrying out the 3rd course of NACT. NACT causes significant changes in the quantity of six CTC subsets, with various combinations of stemness and epithelial-mesenchymal transition (EMT) properties.

Development of Novel Monoclonal Antibodies for Evaluation of Transmembrane Prostate Androgen-Induced Protein 1 (TMEPAI) Expression Patterns in Gastric Cancer.

Transmembrane prostate androgen-induced protein 1 (TMEPAI) is a single-span membrane protein, functionally involved in transforming growth factor beta signaling pathway. The particular protein presented in cells in three isoforms, which differs in the length of the soluble N-terminal extracellular domain, making it challenging for the immunochemical recognition. By using quantitative real-time polymerase chain reaction, we identified significant upregulation of PMEPA1 gene expression in malignant tissues of patients with gastric adenocarcinoma. The main part of commercially available anti-TMEPAI antibodies are having polyclonal nature or not suitable for immunocytochemical localization of target protein in tissue specimens. Hence, we decide to generate a set of novel rat monoclonal antibodies (mAb) directed against conservative C-terminal cytoplasmic epitope. Immunoblotting analysis showed that monoclonal antibodies, 2E1, 6C6, and 10A7 were able to recognize specifically target protein in transiently transfected HEK293T and CHO-K1 cells. Especially established mAb, named 10A7, showed the excellent binding ability to target protein in immunohistochemistry. By using developed antibodies, we observed pronounced expression of TMEPAI in normal gastric epithelial cells while tumor cells from gastric adenomas, and adenocarcinoma samples were mostly negative for target protein expression. Also, we found that gastric epithelium cells lose the TMEPAI expression concurrently with severe dysplasia progression, which probably caused by a mechanism involving specific microRNA.

Expression of vascular endothelial growth factor and transcription factors HIF-1, NF-kB expression in squamous cell carcinoma of head and neck; association with proteasome and calpain activities.

INTRODUCTION: The transcription factors NF-kB, HIF-1 and vascular endothelial growth factors (VEGF) are known to play an important role in pathogenesis of squamous cell carcinoma of head and neck (SCCHN). PURPOSE: The aim of the study was to determine the NF-kB, HIF-1 and VEGF, expression their characteristics in squamous cell carcinoma of head and neck. METHODS: Transcription factors and VEGF expression were measured by ELISA kits. Proteasome and calpain activity were determined using specific fluorogenic substrate. Proteasome subunits composition was measured by Western blot analysis. RESULTS: In the present study, we revealed the connection between SCCHN lymphogenous metastasis development and NF-kB p50 expression. An increase in total, 26S and 20S proteasome activities and calpain activity was observed in cancer tissues in comparison with agreed standard (non-transformed tissue). The dynamics of changes in proteasome activity and proteasome subunits content during lymph nodes metastasis development had a complex pattern. Nonparametric analysis of variance showed the connection between the extent of metastatic affection of regional lymph nodes, total proteasome activity and LMP2 expression. Proteasome and calpain systems corresponded and interacted with each other. We also revealed a positive correlation between the NF-kB p65 and p50 expression and proteasome activity. CONCLUSION: Taken together, our results suggest that above mentioned transcription factors and intracellular proteolytic systems are involved in SCCHN progression and metastasis. Moreover, the opportunity of transcription factors regulation by proteasome takes place in oncogenesis of SCCHN. The results provide a basis for new prognostic tests and development of novel targeted therapy.