Concomitant targeting of FLT3 and BTK overcomes FLT3 inhibitor resistance in acute myeloid leukemia through inhibition of autophagy

Strategies to overcome resistance to FMS-like tyrosine kinase 3 (FLT3)-targeted therapy in acute myeloid leukemia (AML) are urgently needed. We identify autophagy as one of the resistance mechanisms, induced by hypoxia and the bone marrow (BM) microenvironment via Bruton's tyrosine kinase (BTK) activation. Suppressing autophagy/BTK sensitized FLT3-mutated AML to FLT3 inhibitor-induced apoptosis. Further, co-targeting FLT3/BTK/Aurora kinases (AURKs) with a novel multi-kinase inhibitor CG-806 (luxeptinib) induced profound apoptosis induction in FLT3-mutated AML by co-suppressing FLT3/BTK, antagonizing autophagy, and causing leukemia cell death in FLT3 wild-type AML by AURK-mediated G2/M arrest and polyploidy, in addition to FLT3 inhibition. Thus, CG-806 exerted profound anti-leukemia activity against AMLs regardless of FLT3 mutation status. CG-806 further significantly reduced AML burden and extended survival in an in vivo PDX leukemia murine model of FLT3 inhibitorresistant FLT3-ITD/TKD double mutant primary AML. Taken together, CG-806 exerts a unique mechanistic action and pre-clinical activity, suggesting further development in FLT3 wild-type and mutant AML.

Dietary inclusion level effects of distillers dried grains with solubles on broiler meat quality

A completely randomized design with 7 replications (n = 7, treatments = 5 with 8 subsamples per treatment) was used to evaluate the effects of feeding various levels of distillers dried grains with solubles (DDGS; 0, 6, 12, 18, and 24%) on broiler breast and thigh meat quality. Broilers were harvested in a pilot scale processing plant with commercial prototype equipment at 42 d of age. The right half of each breast was evaluated for pH, instrumental color, cooking loss, proximate analysis, and tenderness. The left half of each breast was used for consumer acceptability testing. Thigh meat was evaluated for proximate composition, fatty acid composition, and TBA reactive substances. Breast meat from broilers that were fed DDGS had a higher (P < 0.05) pH than those from the control diet. In addition, the 18 and 24% DDGS treatments yielded breast meat with higher (P < 0.05) pH values than the 6% DDGS treatment. No differences existed (P > 0.05) among breast meat from the different treatments with respect to cooking loss, instrumental color, and consumer acceptability, but breast meat from the control (0% DDGS) treatment had slightly lower (P < 0.05) shear force than breast meat from the 18 and 24% DDGS treatments. In addition, no differences (P > 0.05) existed among proximate composition of breast and thigh meat from the control and DDGS treatments. As DDGS concentration increased, there was a linear increase (P < 0.05) in linoleic and polyunsaturated fatty acids, which indicates a greater potential for lipid oxidation. The TBA reactive substances values were greater (P < 0.05) for the 18 and 24% DDGS treatments at d 5 when compared with the control and 6% DDGS treatments, which indicates increased oxidation. Overall, data suggest that all treatments yielded high-quality breast meat and that thigh meat quality was similar among treatments containing 0 to 12% DDGS, but higher inclusion levels led to thigh meat that was more susceptible to oxidation.

Reemergence of the fetal pattern of L-type calcium channel gene expression in non infarcted myocardium during left ventricular remodeling

The cardiac L-type voltage-dependent calcium channel (VDCC) is a critical component of cardiac action potential and excitation-contraction coupling. The objective of the present study was to examine the changes in expression in Motif IV, an alternatively spliced region of the alpha-1 subunit of the VDCC channel in postmyocardial infarction (MI) remodeled rat left ventricle. RNase protection assay was used to determine alteration in isoform expression in the noninfarcted hypertrophied ventricular myocardium 21 days post myocardial infarction. Our study demonstrates that cardiac hypertrophy is associated with significant increase in the mRNA level of the fetal isoform, with the reversion of fetal:adult isoform ratio to the fetal phenotype. Changes in isoform expression in the post-MI remodeled ventricle, not previously reported, is a pertinent genetic marker of cardiac hypertrophy.