No abstract

A simple bioassay is described for insulin-like activity (lLA) which is based on the incorporation of (3H)glucose into the lipids of isolated rat fat cells. Total lipids were extracted by adding toluene-based scintillation fluid direcdy to the incubation tlasks, and the radioactivity in the lipids measured by liquid scintillation counting. Insulin dose-response curves with (2-3H)-, (3-3H) and (6-3H)glucose were compared and those obtained with (2-3H)glucose and (3-3H) glucose were found suitable for routine use.

The incidence of colorectal cancer is higher in men than in women, amounting to 15% of cancer-related diseases as a whole. As such, undesirable effects, arising from the administration of current chemotherapeutic agents (the FOLFIRI/FOLFOX combinations), which are exerted on the remaining non-cancerous tissues and/or cells, have contributed to the occurrence of resistance to multiple drugs, thus markedly reducing their efficacy. However, the delivery of chemotherapeutic agents may be improved and their action may be more selectively targeted to diseased tissues/cells by means of developing biotechnologies and nano-techniques. Thus, the current focus is on creating biological tissue and related tumor models, by means of three-dimensional (3D) spheres, in an attempt to bridge the gap between results obtained in the pre-clinical phase and promising outcomes obtained in clinical trials. For this purpose, the characterization and use of so-called ‘multicellular tumor spheroids’, may prove to be invaluable. In this study, we focus on describing the efficacy of a model 3D system as compared to the traditional 2D tumor spheres in determining drug response, highlighting a potentially greater effect of the drugs following the encapsulation of respective liposomes. The results obtained demonstrate the successful preparation of a suspension of liposomes loaded with folinic acid, oxaliplatin and 5-fluorouracil (5-FU), and loaded with meso-tetra (4-sulfonatophenyl) porphyrin. Following its use on HT-29 colorectal cancer cells, an important comparative reduction was noted in the viability of the HT-29 cells, demonstrating the efficacy of multicellular tumor spheroids carrying liposomes loaded with therapeutic drugs. These findings indicate that the method of drug encapsulation in liposomes may improve the treatment efficacy of chemotherapeutic agents.

5-FU cytotoxicity mechanism has been assigned both to the miss-incorporation of fluoronucleotides into RNA and DNA and to the inhibition of thymidylate synthase. 5-FU is one of the most widely used chemotherapeutic drugs, although it has severe side effects that may vary between patients. Pharmacogenetic studies related to 5-FU have been traditionally focused on the rate-limiting catabolic enzyme, dihydropyrimidine dehydrogenase that breaks 80–85% of 5-FU into its inactive metabolite. Choosing the right dosing scheme and chemotherapy strategy for each individual patient remains challenging for personalized chemotherapy management. In the general effort toward reduction of colorectal cancer mortality, in vitro screening studies play a very important role. To accelerate translation research, increasing interest has been focused on using in vivo-like models such as three-dimensional spheroids. The development of higher throughput assays to quantify phenotypic changes in spheroids is an active research area. Consequently, in this study we used the microarray technology to reveal the HT-29 colorectal adenocarcinoma cells gene expression signature as response to 5-FU/OXP/FA treatment in a state of the art 3D culture system. We report here an increased reactive oxygen species production under treatment, correlated with a decrease in cell viability and proliferation potential. With respect to the HT-29 cells gene expression under the treatment with 5-FU/OXP/FA, we found 15.247 genes that were significantly differentially expressed (p < 0.05) with a fold change higher that two-fold. Among these, 7136 genes were upregulated and 8111 genes were downregulated under experimental conditions as compared to untreated cells. The most relevant and statistic significant (p < 0.01) pathways in the experiment are associated with the genes that displayed significant differential expression and are related to intracellular signaling, oxidative stress, apoptosis, and cancer.

Rheumatic diseases are highly prevalent chronic disorders and the leading cause of physical disability worldwide, with a marked socio-economic impact. Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of unknown etiology with an autoimmune pathogenesis, characterised by arthropathy with chronic, deforming, destructive evolution and multiple systemic manifestations. The management of RA has undergone significant changes as far as objectives and approaches are concerned, ending in the current strategy known as ‘treat to target’. The therapeutic array of RA includes several categories of medicinal products, of varying potential. There are several criteria for the classification of medicinal products used against this disease, one of the most important and modern of which divides such substances according to their effects on the progress of the disease: symptom-modifying antirheumatic drugs (including non-steroidal anti-inflammatory drugs and corticoids), disease-modifying antirheumatic drugs (including various substances, such as gold salts, antimalarials, sulfasalazine, D-penicillamine; non-specific immunosuppressive medication, such as methotrexate, cyclophosphamide, azathioprine and leflunomide) and biological therapy is a recent addition, providing new insight into the treatment of this disease. The selection of the optimal therapy for RA should be based on guidelines and recommendations, but also on clinical particular aspects and patient preferences.