Crizotinib Has Preclinical Efficacy in Philadelphia-Negative Myeloproliferative Neoplasms.

PURPOSE: The Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) polycythemia vera, essential thrombocythemia, and primary myelofibrosis are characterized by JAK/STAT pathway activation. JAK inhibitors are approved for MPN treatment, but persistence has been observed, due to JAK/STAT reactivation. EXPERIMENTAL DESIGN: Using MPN patient samples, JAK2-mutated cell lines, and MPN mouse models, we examined both the efficacy and mechanism by which crizotinib, the ALK/MET/RON/ROS1 inhibitor approved for the treatment of non-small cell lung cancer, alters MPN cell proliferation and JAK/STAT activation. RESULTS: We found that crizotinib suppresses proliferation and activation of JAK/STAT signaling, and decreases the disease burden in the JAK2V617F mouse model of MPN. Furthermore, we found that crizotinib could overcome JAK inhibitor persistence to ruxolitinib. Interestingly, phosphorylation of the crizotinib target RON kinase was enhanced in ruxolitinib-persistent cells. We show that phospho-JAK2 and phospho-RON can physically interact to sustain JAK/STAT signaling, and that the combination of crizotinib and ruxolitinib disrupts this interaction. Furthermore, RON knockdown suppresses proliferation and activation of JAK/STAT signaling in JAK2-mutated cells, and RON deletion in a JAK2V617F mouse MPN model decreases the disease burden. We also observed RON hyperactivation in MPN patient cells, suggesting that RON may be an important target of crizotinib in MPN. CONCLUSIONS: In summary, we demonstrate that crizotinib has preclinical efficacy in MPN patient cells, JAK2-mutated cell lines, and a JAK2-mutated mouse model, and that the combination of crizotinib with JAK inhibitors suppresses JAK inhibitor persistence. Our work suggests that crizotinib should be investigated for the treatment of patients with MPN.

Effect of protease supplementation on apparent ileal crude protein and amino acid digestibility of over-processed soybean meals in broilers.

BACKGROUND: Nutritional value of proteins in feed ingredients can be negatively affected by hydrothermal processing, which causes large variation in the bioavailability of amino acids (AA) and negatively affects animal productive performance. Supplementation of exogenous proteases could increase the rate of digestion of damaged proteins, thereby increasing overall AA digestibility and bioavailability. The aim was to determine the effect of exogenous protease supplementation on the apparent ileal digestibility (AID) of crude protein (CP) and AA of soybean meals (SBM) with different degrees of hydrothermal processing in broilers. METHODS: The experiment involved a 3 × 2 factorial arrangement, with SBM processing time (commercial SBM or autoclaved for 30 or 60 min at 120 °C) and protease supplementation (not supplemented and supplemented) as factors. Protease was included at three times the recommended dose (0.06%) and the experimental diets were fed from 15 to 21 d. RESULTS: The interaction between the effects of SBM processing and protease supplementation was significant for the AID of CP (P = 0.01), Trp (P = 0.01), Gly (P = 0.03) and Pro (P = 0.03), and also for the average daily gain (P = 0.01) and feed conversion ratio (P = 0.04). Increasing the processing time of SBM decreased (P < 0.0001) the AID of all amino acids, whilst the effect of protease supplementation was only significant for the AID of Phe (P = 0.02) and Tyr (P = 0.01). CONCLUSIONS: Exogenous protease supplementation at three times the commercial dose does not seem to offset the negative effects of hydrothermal processing of SBM on the apparent ileal digestibility of CP and amino acids or performance of broilers. Whilst positive numerical improvements of digestibility and performance (ADG and FCR) were noticed with protease supplementation at relatively mild processing levels, negative results were obtained with the harsh-processed meals.