ALBERT

Description: Licensed medicines available in the U.K. for treating Atlantic salmon infested with sea lice, dichlorvos, azamethiphos, and hydrogen peroxide, can only be administered by bath application. Adverse reactions have been reported to bath treatments including mortalities, inappetance, reduction in growth and reduced louse sensitivity to dichlorvos. The physical constraints of bath treatments are examined and improvements recommended. Oxygen saturation was adequate during treatments but declined rapidly when the tarpaulin was removed. A chemical marker dispersed uniformally both horizontally and vertically in a cage within 5 mins of dispensing indicating dispersal of a medicine is rapid and adequate during treatment. The range in enclosed volumes in 86 treatments was 46 to 146% of theoretical, suggesting potential toxicity due to high concentrations at low volumes and the risk of reduced sensitivity at high volumes. Residual concentrations of hydrogen peroxide varied from 50 to 400 ppm from 5 to 15 mins after the tarpaulin was removed. Water exchange should be encouraged by aerating the cage and flushing at the end of treatment.

Description: Licensed medicines available in the U.K. for treating Atlantic salmon infested with sea lice, dichlorvos, azamethiphos, and hydrogen peroxide, can only be administered by bath application. Adverse reactions have been reported to bath treatments including mortalities, inappetance, reduction in growth and reduced louse sensitivity to dichlorvos. The physical constraints of bath treatments are examined and improvements recommended. Oxygen saturation was adequate during treatments but declined rapidly when the tarpaulin was removed. A chemical marker dispersed uniformally both horizontally and vertically in a cage within 5 mins of dispensing indicating dispersal of a medicine is rapid and adequate during treatment. The range in enclosed volumes in 86 treatments was 46 to 146% of theoretical, suggesting potential toxicity due to high concentrations at low volumes and the risk of reduced sensitivity at high volumes. Residual concentrations of hydrogen peroxide varied from 50 to 400 ppm from 5 to 15 mins after the tarpaulin was removed. Water exchange should be encouraged by aerating the cage and flushing at the end of treatment.

Description: The clinical behavior of thyroid cancers is seen to reflect inherent transcriptional activities of mutated genes and trophic effects on tumors of circulating pituitary thyrotropin (TSH). The thyroid hormone, L-thyroxine (T4), has been shown to stimulate proliferation of a large number of different forms of cancer. This activity of T4 is mediated by a cell surface receptor on the extracellular domain of integrin αvβ3. In this brief review, we describe what is known about T4 as a circulating trophic factor for differentiated (papillary and follicular) thyroid cancers. Given T4′s cancer-stimulating activity in differentiated thyroid cancers, it was not surprising to find that genomic actions of T4 were anti-apoptotic. Transduction of the T4-generated signal at the integrin primarily involved mitogen-activated protein kinase (MAPK). In thyroid C cell-origin medullary carcinoma of the thyroid (MTC), effects of thyroid hormone analogues, such as tetraiodothyroacetic acid (tetrac), include pro-angiogenic and apoptosis-linked genes. Tetrac is an inhibitor of the actions of T4 at αvβ3, and it is assumed, but not yet proved, that the anti-angiogenic and pro-apoptotic actions of tetrac in MTC cells are matched by T4 effects that are pro-angiogenic and anti-apoptotic. We also note that papillary thyroid carcinoma cells may express the leptin receptor, and circulating leptin from adipocytes may stimulate tumor cell proliferation. Transcription was stimulated by leptin in anaplastic, papillary, and follicular carcinomas of genes involved in invasion, such as matrix metalloproteinases (MMPs). In summary, thyroid hormone analogues may act at their receptor on integrin αvβ3 in a variety of types of thyroid cancer to modulate transcription of genes relevant to tumor invasiveness, apoptosis, and angiogenesis. These effects are independent of TSH.

Description: Abstract 2867 Background: Multiple myeloma (MM) is a highly resistant hematological neoplasia that remains an incurable disease. A leading drug in MM treatment is bortezomib, a selective proteasome inhibitor. Current treatment protocols have extended the overall survival of patients with MM, however, ultimately the disease becomes refractory to all forms of treatments and therefore drugs with new mechanisms of action are urgently needed. Experimental and clinical observations suggest that thyroid hormones (T3 and T4) modulate neoplastic cells and activate MAPK pathway through binding to αv β3 integrin, commonly overexpressed in cancer. Tetraiodothyroacetic acid (tetrac), a non-agonist T4 analog, selectively blocks T3 and T4 binding to αv β3 receptor site. MM cells interact with αv β3 for invasion/growth and thyroid diseases were associated with increased MM risk. We recently demonstrated the thyroid hormones- αv β3-MAPK axis in myeloma cells. In the current study we further show that T3 and T4 antagonize bortezomib action via MAPK activation and that in the presence of tetrac bortezomib action is significantly enhanced. Methods: Cell lines: MM cell lines (RPMI-8226, ARK, ARP-1, U266 and CAG) are cultured in RPMI 1640 supplemented with 10% heat-inactivated FBS/antibiotics. Before addition of T3 or T4, cells are grown for 48 hours without serum. Bone marrow (BM) aspirates were obtained from patients with MM treated at the Meir Medical Center. Signed institutional review board–approved written informed consent was obtained from all patients. Primary MM cells were separated on Ficoll gradient and were cultured in RPMI 1640. Reagents and chemicals: T3, T4, tetrac, MAPK inhibitor (U0126), autophagy inhibitor (3MA) and pan caspase inhibitor, Z-VAD. Cells were treated with T3 or T4 (1nM-100nM and 1μM) in the presence/absence of tetrac (100nM and 1μM) and/or bortezomib (25nM) and tested by several methods: Cell number. Cell proliferation assay: WST-1 (10% final concentration) is incubated at 37°C for 2 h and read using microELISA reader at 440nm. Cell cycle: Cells are harvested, fixed and stained with DNA propidium iodide (PI) (50 μg/ml) /RNAse A (10mg/ml) and analyzed for DNA content by FACS. Analysis of apoptosis/necrosis: Cells (105) are incubated with 5 μl Annexin V (FITC conjugated)/5 μl PI and analyzed by FACS. Expression of apoptotic genes (real-time PCR). Results were repeated 2–3 times in triplicates and were analyzed using unpaired students t test. Results and discussion: Results demonstrate that T3 and T4 at near physiological and supra physiological levels, increased myeloma cell viability by 15–50% and cell number by 30%-60%. This increased viability was blocked by U0126, indicating involvement of the MAPK pathway. In parallel a 20–25% reduction in cell death and of pro-apoptotic genes expression was documented following treatment with the hormones. Co-treatment of myeloma cell lines with T3 or T4 reduced bortezomib cytotoxicity and increased cell survival in a MAPK-dependent manner. Pretreatment of MM cell lines and primary cells from MM patients with tetrac, 48 hours before the addition of bortezomib, resulted in a synergistic cytotoxic effect. The effect of tetrac was blocked using a pan-caspase inhibitor (Z-VAD) but not by an autophagy inhibitor (3MA), suggesting apoptosis-related cell death. Conclusions: We present here novel data demonstrating that T3 and T4 may oppose bortezomib action via MAPK activation. Blocking the thyroid hormones- αv β3 axis using tetrac, promotes bortezomib cytotoxicity, suggesting this approach as a promising adjunct therapy in MM. Disclosures: No relevant conflicts of interest to declare.