Limits...
Aspartate-modified doxorubicin on its N-terminal increases drug accumulation in LAT1-overexpressing tumors.

Wu W, Dong Y, Gao J, Gong M, Zhang X, Kong W, Li Y, Zeng Y, Si D, Wei Z, Ci X, Jiang L, Li W, Li Q, Yi X, Liu C - Cancer Sci. (2015)

Bottom Line: In vitro, Asp-DOX exerted stronger inhibition on the cancer cells overexpressing LAT1 and the uptake of Asp-DOX was approximately 3.5-fold higher than that of DOX in HepG2 cells.Pharmacokinetic data also showed that Asp-DOX was expressed over a longer circulation time (t1/2 = 49.14 min) in the blood compared to DOX alone (t1/2 = 15.12 min).Furthermore, after Asp modification, Asp-DOX avoided MDR mediated by P-glycoprotein.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.

Show MeSH

Related in: MedlinePlus

Inhibitory effects of different amino acid-modified compounds on the uptake of L-[H3] leucine by the S2-LAT1 transgene cell line. (a) Uptake of L-[3H] Leu (2Ā Ī¼mol/L) in S2-LAT1 with or without tested compounds at a concentration of 100Ā Ī¼mol/L (*PĀ <Ā 0.05; **PĀ <Ā 0.01). (b) Inhibition of aspartate-modified doxorubicin (Asp-DOX) at different concentrations on the uptake of L-[3H] Leu (2Ā Ī¼mol/L). (c, d) Inhibition of different amino acids (100Ā Ī¼mol/L) on the uptake of Asp-DOX (20Ā Ī¼mol/L) (c) or DOX (20Ā Ī¼mol/L) (d) by S2-LAT1 cells. (e) Curve of the Michaelisā€“Menten equation through Eadieā€“Hofstee linear regression to obtain the Michaelis constant (Km).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4471785&req=5

fig01: Inhibitory effects of different amino acid-modified compounds on the uptake of L-[H3] leucine by the S2-LAT1 transgene cell line. (a) Uptake of L-[3H] Leu (2Ā Ī¼mol/L) in S2-LAT1 with or without tested compounds at a concentration of 100Ā Ī¼mol/L (*PĀ <Ā 0.05; **PĀ <Ā 0.01). (b) Inhibition of aspartate-modified doxorubicin (Asp-DOX) at different concentrations on the uptake of L-[3H] Leu (2Ā Ī¼mol/L). (c, d) Inhibition of different amino acids (100Ā Ī¼mol/L) on the uptake of Asp-DOX (20Ā Ī¼mol/L) (c) or DOX (20Ā Ī¼mol/L) (d) by S2-LAT1 cells. (e) Curve of the Michaelisā€“Menten equation through Eadieā€“Hofstee linear regression to obtain the Michaelis constant (Km).

Mentions: LAT1-mediated L-[3H] leucine uptake (2Ā Ī¼mol/L) was measured in the presence of 100Ā Ī¼mol/L concentrations of non-labeled compounds (Fig.1). As shown in Figure1(a), L-[3H] leucine uptake was markedly inhibited by Asp-DOX and Tyr-DOX, especially Asp-DOX, whereas the other compounds (Leu-DOX, Val-DOX, Met-DOX, Phe-DOX, and Ile-DOX) barely inhibited the uptake of L-[3H] leucine by S2-LAT1. Furthermore, in order to check the inhibition of Asp-DOX to the uptake of L-leucine, we inspected its IC50 (Fig.1b). Asp-DOX exerted high inhibition on the uptake of L-leucine and its IC50 to L-leucine was determined to be approximately 30.12Ā Ī¼mol/L. In order to check whether the internalization of Asp-DOX was mediated by LAT1, the inhibition to the uptake of Asp-DOX by different amino acids (Leu, Met, and Phe, substrates of LAT1; Ala, Glu, and Gly, non-substrates of LAT1) was determined with or without 100Ā Ī¼mol/L amino acids. The results showed that 100Ā Ī¼mol/L Leu, Met, and Phe strongly inhibited the uptake of Asp-DOX, whereas 100Ā Ī¼mol/L Ala, Glu, and Gly had no inhibition (Fig.1c). However, neither 100Ā Ī¼mol/L Leu, Met, or Phe, nor 100Ā Ī¼mol/L Ala, Glu, or Gly inhibited the uptake of DOX by S2-LAT1 cells (Fig.1d). In order to check the affinity of Asp-DOX to LAT1, the Michaelisā€“Menten curve was plotted. The results showed that the Km of Asp-DOX with LAT1 was determined as 41.423Ā Ī¼mol/L (Fig.1e). These results suggested that the internalization of Asp-DOX into S2-LAT1 cells was mainly mediated by LAT1.


Aspartate-modified doxorubicin on its N-terminal increases drug accumulation in LAT1-overexpressing tumors.

Wu W, Dong Y, Gao J, Gong M, Zhang X, Kong W, Li Y, Zeng Y, Si D, Wei Z, Ci X, Jiang L, Li W, Li Q, Yi X, Liu C - Cancer Sci. (2015)

Inhibitory effects of different amino acid-modified compounds on the uptake of L-[H3] leucine by the S2-LAT1 transgene cell line. (a) Uptake of L-[3H] Leu (2Ā Ī¼mol/L) in S2-LAT1 with or without tested compounds at a concentration of 100Ā Ī¼mol/L (*PĀ <Ā 0.05; **PĀ <Ā 0.01). (b) Inhibition of aspartate-modified doxorubicin (Asp-DOX) at different concentrations on the uptake of L-[3H] Leu (2Ā Ī¼mol/L). (c, d) Inhibition of different amino acids (100Ā Ī¼mol/L) on the uptake of Asp-DOX (20Ā Ī¼mol/L) (c) or DOX (20Ā Ī¼mol/L) (d) by S2-LAT1 cells. (e) Curve of the Michaelisā€“Menten equation through Eadieā€“Hofstee linear regression to obtain the Michaelis constant (Km).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4471785&req=5

fig01: Inhibitory effects of different amino acid-modified compounds on the uptake of L-[H3] leucine by the S2-LAT1 transgene cell line. (a) Uptake of L-[3H] Leu (2Ā Ī¼mol/L) in S2-LAT1 with or without tested compounds at a concentration of 100Ā Ī¼mol/L (*PĀ <Ā 0.05; **PĀ <Ā 0.01). (b) Inhibition of aspartate-modified doxorubicin (Asp-DOX) at different concentrations on the uptake of L-[3H] Leu (2Ā Ī¼mol/L). (c, d) Inhibition of different amino acids (100Ā Ī¼mol/L) on the uptake of Asp-DOX (20Ā Ī¼mol/L) (c) or DOX (20Ā Ī¼mol/L) (d) by S2-LAT1 cells. (e) Curve of the Michaelisā€“Menten equation through Eadieā€“Hofstee linear regression to obtain the Michaelis constant (Km).
Mentions: LAT1-mediated L-[3H] leucine uptake (2Ā Ī¼mol/L) was measured in the presence of 100Ā Ī¼mol/L concentrations of non-labeled compounds (Fig.1). As shown in Figure1(a), L-[3H] leucine uptake was markedly inhibited by Asp-DOX and Tyr-DOX, especially Asp-DOX, whereas the other compounds (Leu-DOX, Val-DOX, Met-DOX, Phe-DOX, and Ile-DOX) barely inhibited the uptake of L-[3H] leucine by S2-LAT1. Furthermore, in order to check the inhibition of Asp-DOX to the uptake of L-leucine, we inspected its IC50 (Fig.1b). Asp-DOX exerted high inhibition on the uptake of L-leucine and its IC50 to L-leucine was determined to be approximately 30.12Ā Ī¼mol/L. In order to check whether the internalization of Asp-DOX was mediated by LAT1, the inhibition to the uptake of Asp-DOX by different amino acids (Leu, Met, and Phe, substrates of LAT1; Ala, Glu, and Gly, non-substrates of LAT1) was determined with or without 100Ā Ī¼mol/L amino acids. The results showed that 100Ā Ī¼mol/L Leu, Met, and Phe strongly inhibited the uptake of Asp-DOX, whereas 100Ā Ī¼mol/L Ala, Glu, and Gly had no inhibition (Fig.1c). However, neither 100Ā Ī¼mol/L Leu, Met, or Phe, nor 100Ā Ī¼mol/L Ala, Glu, or Gly inhibited the uptake of DOX by S2-LAT1 cells (Fig.1d). In order to check the affinity of Asp-DOX to LAT1, the Michaelisā€“Menten curve was plotted. The results showed that the Km of Asp-DOX with LAT1 was determined as 41.423Ā Ī¼mol/L (Fig.1e). These results suggested that the internalization of Asp-DOX into S2-LAT1 cells was mainly mediated by LAT1.

Bottom Line: In vitro, Asp-DOX exerted stronger inhibition on the cancer cells overexpressing LAT1 and the uptake of Asp-DOX was approximately 3.5-fold higher than that of DOX in HepG2 cells.Pharmacokinetic data also showed that Asp-DOX was expressed over a longer circulation time (t1/2 = 49.14 min) in the blood compared to DOX alone (t1/2 = 15.12 min).Furthermore, after Asp modification, Asp-DOX avoided MDR mediated by P-glycoprotein.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.

Show MeSH
Related in: MedlinePlus