TY - JOUR T1 - Evaluation of the amino acid transporter: comparison study between FBPA and BPA in vitro. JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1112 LP - 1112 VL - 56 IS - supplement 3 AU - Hayato Ikeda AU - Tadashi Watabe AU - Shushi Nagamori AU - Yoko Tanaka AU - Pattama Wiriyasermkul AU - Yasukazu Kanai AU - Sadahiro Naka AU - Eku Shimosegawa AU - Yoshikatsu Kanai AU - Jun Hatazawa Y1 - 2015/05/01 UR - http://jnm.snmjournals.org/content/56/supplement_3/1112.abstract N2 - 1112 Objectives 4-borono-phenylalanine (BPA) has been used as carrier of 10B into the tumor for boron neutron capture therapy. The PET tracer 18F-FBPA is used to estimate uptake of BPA. In this work, we compared the accumulation FBPA and BPA to evaluate the contribution of L-type amino acid transporter (LAT), focusing on the LAT1 which is highly expressed in the many types of tumors.Methods In vitro assay was performed using two cell lines: HEK293-LAT1 (high expression of LAT1) and HEK293-LAT2 (high expression of LAT2). We evaluated affinity of LATs by uptake inhibitory effects of 14C-leucine for LAT1 and 14C-alanine for LAT2 in the presence of BCH (LAT inhibiter), BPA, and cold FBPA, respectively. To evaluate transport capacity of LATs, the efflux analysis was performed by counting the extracellular 14C-leucine for LAT1 and 14C-alanine for LAT2 after the addition of tyrosine, BPA, and cold FBPA, respectively.Results Inhibitory effects were 49.5±1.0% with FBPA and 48.1±2.9% with BPA in HEK293-LAT1, 70.8±3.3% with FBPA and 37.4±2.2% with BPA in HEK293-LAT2. Effluxes were 28.9±1.7%/min with FBPA and 30.9%/min with BPA in HEK293-LAT1, 30.8%/min with FBPA and 42.7%/min with BPA in HEK293-LAT2. No significant difference was observed between FBPA and BPA in the affinities and transport capacities for LAT1, whereas those for LAT2 were significantly lower in FBPA than in BPA (p<0.01 and p<0.05, respectively).Conclusions This study demonstrated both FBPA and BPA showed the same selectivity and transport property for LAT1, suggesting the effectiveness of 18F-FBPA-PET to estimate BPA accumulation in the tumor. However, attention must be paid for the 18F-FBPA-PET evaluation of normal organs rich in LAT2. ER -