L-amino acid transporter 1 ( LAT1) is a member of L-amino transporter family and an important heterodi?meric amino acid transporter that belongs to subfamily of SLC7. LAT1 mainly mediates trans-membrane transportation of those neutral amino acids that had cyclobenzene or long side chains with high molecular mass such as L-Leu, L-Met and L-Phe as well as some amino acid analogues such as melphalan, L-DOPA and thyroxine in a Na+and ATP-independent diffu?sion. As LAT1 was abnormally overexpressed in various transformed cell lines, it might be related with tumor stage and prog?nosis. It is not only a biomarker that specifically expressed in some tumor cells but also plays an important role in tumor diag?nosis and therapy. Here we demonstrate the structure of LAT1 and its mechanism in transport peculiarity. We also reviewed the development of LAT1 in tumor diagnosis and treatment.

Objective To study the inhibition of berberine on organ anion transporters (OATs) and its bidirectional trans-membrane transport.Method The transgene cell lines of the organ anion transporters including OAT1,OAT2,OAT3,OAT4,OAT7,and URAT1 were constructed and selected by animal cell transgenic method mediated by transporter Lipo 3000.Wild type (WT) cells were used as control group,and activity of OATs was verified by adding their radiolabeled substrates and inhibitors.The inhibition of 100 μmol/L berberine on the transporters was investigated in vitro.The IC50 of berberine on URAT1 was also determined.The bidirectional transport of berberine was studied through the Caco-2 model.Result The results showed that 100 μmol/L berberine inhibited the activity of OAT1,OAT2,OAT3,OAT4,OAT7 and URAT1 to (70.48±4.23)％,(69.13±1.28)％,(72.12±3.28)％,(79.77±6.49)％,(69.51 ±5.99)％ and (38.4 ± 2.67)％ respectively,the IC50 of berberine to URAT 1 was 13.19 μmol/L,the Papp (A-B) of 50 μmol/L and 100 μmol/L berberine were separately 0.28 × 10-6 and 0.40 × 10-6 cm/s,and the effiux rates were separately 3.18 and 3.15.Conclusion Berberine shows a stronger inhibition to URAT1 compared to OAT1,OAT2,OAT3,OAT4 and OAT7.Berberine may be the substrate of some effiux transporters.This study provides theoretical basis for explaining the low bioavailability ofberberine and forecasting the possible drug-drug interaction.

Objective To study the inhibitory effects ofberberine on human organic cation transporter (OCTs) including OCT1,OCT2,OCT3,OCTN1 and OCTN2.Methods Using animal cell transgenic method mediated by transporter Lipo 3000,the drug transporters over expression cell lines S2-OCT1,S2-OCT2,S2-OCT3,S2-OCTN1 and S2-OCTN2 were obtained by selective medium culture.The OCTs evaluation model was established by detecting the trans-membrane transport of radioactive substrate in vitro.Wild type (WT) cells were used as control group,activity of OCTs was verified by adding its inhibitor.The inhibition of berberine on the transporters was investigated in vitro.The IC50 of inhibitory effect of berberine on various drug transporters was also calculated.Result The transport activity of transporter cell lines was increased by more than 5 times compared to the WT cell line respectively,what's more,their transport activity decreased significantly by their corresponding inhibitor.The ICs0 of berberine to OCT1,OCT2,OCT3,OCTN1 and OCTN2 were respectively 7.63,6.80,2.25,4.66 and 210.34 μmol/L.Conclusion Berberine significant inhibition to OCT1,OCT2,OCT3,OCTN1 and OCTN2.The inhibition on OCT1,OCT2,OCT3,OCTN1 is stronger compared to OCTN2.

This study aimed to investigate the improvement of tolance and pharmacodynamics of nano-micelle irinotecan formulation compared with irinotecan hydrochloride injection(Campto). The toxic effects of the two formulations on colorectal cancer cells COLO205, HT-29, HCT-8 and SW480 were tested in vitro. COLO205 tumor-bearing mouse model was constructed. The two preparations were given via tail vein injection to investigate the maximum tolerance dose(MTD)of tumor-bearing mice to the two preparations, and then to explore the improvement of anti-tumor efficacy of nano-micelle irinotecan formulation near the MTD. The results showed that there was no significant difference in the inhibitory effect of the two formulations on the four colorectal cancer cells in vitro. The MTD of nano-micelle irinotecan formulation and Campto was 432. 0 and 276. 5 mg/m2 respectively. Both of the two formulations showed significant anti-tumor effect in vivo, and the relative tumor proliferation rate and tumor wet weight inhibition rate of nano-micelle irinotecan formulation at high dose(345. 6 mg/m2)were significantly better than those of Campto at two doses(177. 0 and 221. 2 mg/m2)(P< 0. 05).