Carrier-mediated uptake of 1-(2-methoxyethyl)-2-methyl-4,9-dioxo-3-(pyrazin-2-ylmethyl)-4,9-dihydro-1H-naphtho[2,3-d]imidazolium bromide (YM155 monobromide), a novel small-molecule survivin suppressant, into human solid tumor and lymphoma cells.
1-(2-Methoxyethyl)-2-methyl-4,9-dioxo-3-(pyrazin-2-ylmethyl)-4,9-dihydro-1H-naphtho[2,3-d]imidazolium bromide (YM155 monobromide) is a novel small-molecule survivin suppressant that induces the down-regulation of survivin and exhibits potent antitumor activity in nude mice bearing the human hormone refractory prostate carcinoma cell line PC-3. In this study, radioluminographic determination of the in vivo distribution of radioactivity after administration of [(14)C]YM155 to PC-3-xenografted nude mice revealed a relatively high level of radioactivity in the PC-3 xenograft. Therefore, the uptake of [(14)C]YM155 was further characterized in vitro using PC-3, lung cancer (Calu-6 and NCI-H358), malignant melanoma (A375 and SK-MEL-5), and non-Hodgkin's lymphoma (RL and Ramos) cell lines. The uptake of [(14)C]YM155 in these cell lines was dependent on incubation time, temperature, and drug concentration. The Michaelis-Menten constant values were similar among the seven cell lines (0.189-0.367 microM). The effects of various compounds on the uptake of [(14)C]YM155 were tested in PC-3, Calu-6, A375, RL, and Ramos cell lines. Of the compounds tested, the cationic transporter substrates/inhibitors (tetraethylammonium, 1-methyl-4-phenylpyridium, cimetidine, prazosin, corticosterone, verapamil, amantadine, procainamide, and N-methylnicotinamide) inhibited the uptake of [(14)C]YM155 to a similar extent among the five cell lines. The half-maximal inhibitory concentration values (IC(50)) of several compounds for the uptake of [(14)C]YM155 into PC-3 differed from those reported in the literature for human organic cation transporter 1 (OCT1/SLC22A1), OCT2 (SLC22A2), and OCT3 (SLC22A3). To summarize, YM155 was taken up into cancer cells in a carrier-mediated manner and with a similar affinity among all the cancer cell lines tested. An influx transporter(s) may contribute to this process.
Minematsu
Tsuyoshi
T
Drug Metabolism Research Laboratories, Astellas Pharma Inc., 1-8, Azusawa 1-chome, Itabashi-ku, Tokyo 174-8511, Japan. tsuyoshi.minematsu@jp.astellas.com
Iwai
Megumi
M
Sugimoto
Kenji
K
Shirai
Nobuaki
N
Nakahara
Takahito
T
Usui
Takashi
T
Kamimura
Hidetaka
H
D000818:Animals; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D004337:Drug Carriers; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D051034:Inhibitor of Apoptosis Proteins; D008223:Lymphoma / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors*; D009285:Naphthoquinones / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D000077022:Survivin
C107489:BIRC5 protein, human; D002250:Carbon Radioisotopes; D004337:Drug Carriers; D007093:Imidazoles; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009285:Naphthoquinones; D000077022:Survivin; C523798:sepantronium