Irinotecan is a topoisomerase I inhibitor for LoVo cells and HT-29 cells with IC50 of 15.8 μM and 5.17 μM, respectively
(+)-Irinotecan is a Topo I inhibitor.
ChEBI: A member of the class of pyranoindolizinoquinolines that is the carbamate ester obtained by formal condensation of the carboxy group of [1,4'-bipiperidine]-1'-carboxylic acid with the phenolic hydroxy group of (4S)-4,11-diethyl-4,9-dihydro
y-1H-pyrano[3',4':6,7]indolizino[1,2- hydrochloride]quinoline-3,14-dione. Used (in the form of its hydrochloride salt trihydrate) in combination with fluorouracil and leucovorin, for the treatment of patients with metastatic adenocarcino
a of the pancreas after disease progression following gemcitabine-based therapy. It is converted via hydrolysis of the carbamate linkage to its active metabolite, SN-38, which is ~1000 times more active.
Camptosar (Pharmacia &Upjohn)
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irinotecan (cpt-11), a prodrug for treating metastatic colorectal cancer, is a topoisomerase i inhibitor for lovo cells and ht-29 cells with ic50 of 15.8 μm and 5.17 μm, respectively [1].in vivo, irinotecan is converted to sn-38, its most active metabolite, by carboxylesterase converting enzyme (cce) [2].
irinotecan induced similar amounts of cleavable complexes in lovocells and ht-29 cell lines with the ic50 of 15.8 μm and 5.17 μm, respectively [1].after addition of 157 mm irinotecan to plasma, sn-38 concentration showed linear increase during the first 60-min period, followed by a plateau.in the first 60 min, mean and standard deviation of the conversion rate were 515.9 ± 50.1 pmol/ml/h (n = 69), with a coefficient of variation of 0.097 [2]. irinotecan (cpt-11) was significantly more active in sclc than in nsclccelllines (p = 0.0036). ce activity appeared to be associated with higher sensitivity to cpt-11 in human lung cancercelllines and may partly explain the difference in the in vitro sensitivity to cpt-11 between sclc and nsclccells [3].in vitro, the sensitivity to cpt-11 and sn-38 was highest in ls174t and colo 320cells, intermediate in sw1398cellsand lowest in colo 205 and widr cells. the activity of sn-38 was 130 to 570 times than cpt-11[4].
in colo 320 xenografts, irinotecan induced a maximum growth inhibition of 92% [4].a single dose of irinotecan significantly increased amounts of topoisomerase i covalently bound to dna in stomach, duodenum, colon and liver. concomitantly, the irinotecan-treated group exihibited significantly higher amounts of dna strand breaks in colon mucosa cells compared to the control group [5].
[1]. tobin p, clarke s, seale j p, et al. the in vitro metabolism of irinotecan (cpt‐11) by carboxylesterase and β‐glucuronidase in human colorectal tumours[j]. british journal of clinical pharmacology, 2006, 62(1): 122-129.
[2]. shingyoji m, takiguchi y, watanabe‐uruma r, et al. in vitro conversion of irinotecan to sn‐38 in human plasma[j]. cancer science, 2004, 95(6): 537-540.
[3]. van ark-otte j, kedde m a, van der vijgh w j, et al. determinants of cpt-11 and sn-38 activities in human lung cancer cells[j]. british journal of cancer, 1998, 77(12): 2171.
[4]. jansen w j m, zwart b, hulscher s t m, et al. cpt-11 in human colon-cancer cell lines and xenografts: characterization of cellular sensitivity determinants[j]. international journal of cancer, 1997, 70(3): 335-340.
[5]. na y s, jung k a, kim s m, et al. the histone deacetylase inhibitor pxd101 increases the efficacy of irinotecan in in vitro and in vivo colon cancer models[j]. cancer chemotherapy and pharmacology, 2011, 68(2): 389-398.
