Critical shifts in lipid metabolism promote megakaryocyte differentiation and proplatelet formation.

During megakaryopoiesis, megakaryocytes (MK) undergo cellular morphological changes with strong modification of membrane composition and lipid signaling. Here we adopt a lipid-centric multiomics approach to create a quantitative map of the MK lipidome during maturation and proplatelet formation. Data reveal that MK differentiation is driven by an increased fatty acyl import and de novo lipid synthesis, resulting in an anionic membrane phenotype. Pharmacological perturbation of fatty acid import and phospholipid synthesis blocked membrane remodeling and directly reduced MK polyploidization and proplatelet formation resulting in thrombocytopenia. The anionic lipid shift during megakaryopoiesis was paralleled by lipid-dependent relocalization of the scaffold protein CKIP-1 and recruitment of the kinase CK2α to the plasma membrane, which seems to be essential for sufficient platelet biogenesis. Overall, this study provides a framework to understand how the MK lipidome is altered during maturation and the impact of MK membrane lipid remodeling on MK kinase signaling involved in thrombopoiesis.

Stability of African Swine Fever Virus in Carcasses of Domestic Pigs and Wild Boar Experimentally Infected with the ASFV "Estonia 2014" Isolate.

Europe is currently experiencing a long-lasting African swine fever (ASF) epidemic, both in domestic pigs and wild boar. There is great concern that carcasses of infected wild boar may act as long-term virus reservoirs in the environment. We evaluated the tenacity of ASF virus (ASFV) in tissues and body fluids from experimentally infected domestic pigs and wild boar, which were stored on different matrices and at different temperatures. Samples were analysed at regular intervals for viral genome and infectious virus. ASFV was most stable in spleen or muscles stored at -20 °C and in blood stored at 4 °C. In bones stored at -20 °C, infectious virus was detected for up to three months, and at 4 °C for up to one month, while at room temperature (RT), no infectious virus could be recovered after one week. Skin stored at -20 °C, 4 °C and RT remained infectious for up to three, six and three months, respectively. In urine and faeces, no infectious virus was recovered after one week, irrespective of the matrix. In conclusion, tissues and organs from decomposing carcasses that persist in the environment for a long time can be a source of infection for several months, especially at low temperatures.

Targeting the proteasome as a promising therapeutic strategy in thyroid cancer.

BACKGROUND AND OBJECTIVES: Targeting the ubiquitin-proteasome system by using proteasome inhibitors represents a novel approach for cancer therapy. Anaplastic thyroid cancer (ATC), a subtype of thyroid cancer (TC), fails to respond to conventional TC treatment. Here we investigated the effects of bortezomib on TC in vitro. Further, the study aimed to evaluate its potential for TC treatment in vivo. METHODS: Three anaplastic (Hth74, C643, Kat4), one follicular (FTC133), and one papillary (TPC1) TC cell lines were used. Antiproliferative, proapoptotic, and transcriptional effects of bortezomib treatment were analyzed in vitro and growth inhibition of ATC xenografts in vivo. Tumor samples were analyzed by Ki67, CD31, caspase-3, and NF-κB immunohistochemistry. RESULTS: In vitro, bortezomib inhibited proliferation of TC cells (IC(50) 4-10 nM), increased caspase-3 activity and induced cell cycle arrest. NF-κB activity was affected differently. In vivo, bortezomib treatment was effective in reducing tumor volume (up to 74%), accompanied by reduced proliferation (Ki67) and 57% reduced tumor vascularity. CONCLUSION: Proteasome inhibition is effective in reducing cell growth and inducing apoptosis of ATC in vitro and inhibiting tumor growth and vascularity in vivo. However, the impact on nuclear transcription remains controversial. Clinical evaluation of bortezomib treatment in ATC is warranted.

Evaluation of Aurora kinase inhibition as a new therapeutic strategy in anaplastic and poorly differentiated follicular thyroid cancer.

Due to an unfavorable prognosis using the usual therapy, patients with anaplastic thyroid cancer (ATC) are in desperate need of new therapeutic strategies. The objective of this study was to evaluate the effects of MLN8054, an inhibitor of the Aurora serine/threonine kinases, on ATC cells in vitro and on ATC xenografts as a new therapeutic strategy for ATC. Three anaplastic (Hth74, C643, Kat4) and one follicular (FTC133) thyroid cancer cell lines were evaluated in vitro and Kat4 xenografts in vivo. The antiproliferative effect of MLN8054 (0.1-10 µM) on thyroid cancer cells was quantified by sulphorhodamine B-assay. The proapoptotic effect and the effects on the cell cycle were evaluated by flow cytometry after Annexin-V-FITC staining. Further Histone H3 phosphorylation was analysed. In vivo, antiproliferative and antiangiogenic effects were assessed by tumor volume and morphometric analysis following immunohistochemical staining (Ki-67, pHisH3, CD31). Treatment of the different TC cells with MLN8054 inhibited proliferation in a time- and dose-dependent manner, with IC(50) values between 0.1 and 10 µM. Administration of MLN8054 resulted in an increase of apoptotic cells, decreased Histone H3 phosphorylation and induced cell cycle arrest. In vivo, treatment of ATC by MLN8054 resulted in an up to 86% reduced tumor volume and 89% reduced tumor vascularity. In conclusion, our data demonstrated that Aurora kinase inhibition is effective in reducing cell growth and inducing apoptosis of ATC in vitro and tumor growth and vascularity in vivo. Controlled clinical studies on MLN8054 or comparable compounds would be worthwhile to evaluate its potential therapeutic value for treatment of ATC.