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Fatty acid binding protein 3 (FABP3) is expressed both in tumor cells and in the tumor vasculature, making it a potential target for medical imaging and therapy. In this study, we aimed to radiolabel a CooP peptide with a free amino and thiol group, and evaluate the radiolabeled product [ 18 F]FNA- N -CooP for imaging FABP3 expression in breast cancer brain metastases by positron emission tomography. [ 18 F]FNA- N -CooP was prepared by highly chemoselective N -acylation and characterized using different chemical approaches. We validated its binding to the target using in vitro tissue section autoradiography and performed stability tests in vitro and in vivo. [ 18 F]FNA- N -CooP was successfully synthesized in 16.8% decay-corrected radiochemical yield with high radiochemical purity (98.5%). It exhibited heterogeneous binding on brain metastasis tissue sections from a patient with breast cancer, with foci of radioactivity binding corresponding to FABP3 positivity. Furthermore, the tracer binding was reduced by 55% in the presence of nonradioactive FNA- N -CooP a blocker, indicating specific tracer binding and that FABP3 is a viable target for [ 18 F]FNA- N -CooP. Favorably, the tracer did not bind to necrotic tumor tissue. However, [ 18 F]FNA- N -CooP displayed limited stability both in vitro in mouse plasma or human serum and in vivo in mouse, therefore further studies are needed to improve the stability [ 18 F]FNA- N -CooP to be used for in vivo applications.

The molecular mechanisms on milk fat depression (MFD) in response to trans-10,cis-12-conjugated linoleic acid (t10,c12-CLA) supplementation in ruminants were elucidated in this research with dairy goats. A total of 30 2-year-old Xinong Saanen dairy goats [40 ± 5 days in milk (DIM)] at peak lactation stage were assigned to a 3 × 3 Latin square design (14 day treatment period, followed with 14 day washout). Three CLA treatments included (a) control, fed the basal diet only without CLA supplementation; (b) orally supplemented with 8 g/day of lipid-encapsulated CLA (low dose, CLA-1); and (c) orally supplemented with 16 g/day of lipid-encapsulated CLA (high dose, CLA-2). Expression levels of fatty acid metabolism genes in the mammary tissues were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) in three goats on day 1 and the other three goats on day 14 in each group after the discontinuation of CLA treatment in the third experimental period. Dietary supplementation of CLA led to a significant decrease of milk fat compared to the control (p < 0.05). Milk fat concentrations in CLA-1 and CLA-2 groups were 2.74 and 2.42%, respectively, while the milk fat concentration in the control group was 2.99%. Decreases in short- and medium-chain fatty acids (<16 carbons) and increases in unsaturated fatty acids were observed in the CLA-2 group (p < 0.05). The desaturation indexes of C16 and C18 fatty acids were obviously increased (p < 0.01). RT-qPCR results revealed decreases of the mRNA expression levels of SREBF1, PPARG, LPL, CD36, FABP3, ACSL1, FASN, ACACA, DGAT2, TIP47, ADRP, and BTN1A1 genes in mammary glands (p < 0.05) and an increase of the SCD gene because of CLA supplementation (p < 0.05). In conclusion, t10,c12-CLA-induced MFD was possibly the result from the downregulation of genes involved in lipogenesis in goat mammary glands.