Hydroxylated Metabolites of Thalidomide: Formation In-vitro and In-vivo in Man

Eriksson, Tommy; Björkman, Sven; Roth, Bodil; Björk, Henrik; Höglund, Peter

doi:10.1111/j.2042-7158.1998.tb03368.x

Cited by 53 publications

(46 citation statements)

References 21 publications

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“…39) Further, both 5-and 5Ј-hydrox analogs of thalidomide were isolated after activated with S9 fraction of human liver cells. 57) Thus the differential response of rats versus rabbits and humans to thalidomide could be explained by this difference in hydroxylation. Our finding that 5-hydroxy thalidomide, a product of the epoxide intermediate, has an active anti-angiogenic effect in the CAM assay implies that the reactive arene intermediate is not the only active thalidomide metabolite.…”

Section: Discussionmentioning

confidence: 99%

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Effects of Putative Hydroxylated Thalidomide Metabolites on Blood Vessel Density in the Chorioallantoic Membrane (CAM) Assay and on Tumor and Endothelial Cell Proliferation.

Marks

Shi

Fry

et al. 2002

Biological & Pharmaceutical Bulletin

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Angiogenesis, the process of blood vessel formation from pre-formed vessels, has recently become a primary target of anticancer therapy. This is due in part to the finding that removing the blood supply to a tumor can not only prevent further growth but can also starve the existing cells to death.2) In the past several years there have been many potential anti-angiogenic agents developed acting by many mechanisms including interruption of growth factor receptor phosphorylation, [3][4][5] growth factor-receptor binding, 6,7) cell adhesion molecule expression and signaling 8,9) and alterations in endothelial cell apoptosis. 10,11) In addition, several agents such as thalidomide have been shown to inhibit angiogenesis by an as yet not fully understood mechanism.12-18) Furthermore, thalidomide has been shown to reduce tumor growth both in model systems [19][20][21] and in patients. [22][23][24][25][26][27][28] Clinically, however, thalidomide has a fairly weak effect as a monotherapy in patients with solid tumors [22][23][24] but is showing tremendous promise against multiple myeloma.25-28) It has been shown that activation of thalidomide by human or rabbit liver enzymes, but not by rat liver enzymes, significantly enhances the anti-angiogenic effect of the drug in rat aortic sections or isolated endothelial cells.29) This is very interesting because thalidomide is virtually non-toxic to rats when given orally (PO). Intraperitoneal (IP), administration however, commonly associated with "first-pass" hepatic metabolism, 30) recapitulates the teratogenic effect of thalidomide in rats. 31)Kenyon et al. 19) also showed that thalidomide given IP was effective as an anti-angiogenic agent in the mouse corneal model, whereas thalidomide given PO was inactive. In addition, thalidomide teratogenesis was only found to occur after activation of the drug by liver enzymes. 13,[32][33][34][35] Furthermore, in a Xenopus oocyte assay of teratogenesis, activation of thalidomide by a single cytochrome P450 enzyme, CYP2E1, lead to a teratogenic compound whereas unactivated thalidomide was non-teratogenic.35) Thus metabolism of thalidomide is critical to its anti-angiogenic and teratogenic activity. However, the identity of the active anti-angiogenic and teratogenic moiety or moieties of thalidomide are still unknown.The goal of this work was to explore the effect of putative hydroxylated thalidomide metabolites on blood vessel density and target cell proliferation. Since the anti-angiogenic activity of thalidomide was first reported, 36) only a limited number of thalidomide metabolites have been tested for antiangiogenic activity. Figure 1 shows known and hypothesized metabolites of thalidomide (structures M1-M8) based on extensive literature review. [37][38][39][40][41][42][43][44][45] Thalidomide can be metabolized through hydrolysis at the glutarimide and/or phthalimide ring to yield metabolites such as M6-M8. Its hydroxylation can occur on glutarimide or phthalimide ring to yield metabolites M1-M5. Interestingly, only metabolites M5...

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Section: Discussionmentioning

confidence: 99%

“…1) were then synthesized. 47) The purity of all putative metabolites was determined by NMR and by HPLC 57,58) and found to be over 95% in all cases. Figure 3 represents data from the eight putative thalidomide metabolites tested in the CAM assay.…”

Section: Effect Of Microsomal Incubation Of Thalidomide Onmentioning

confidence: 99%

Effects of Putative Hydroxylated Thalidomide Metabolites on Blood Vessel Density in the Chorioallantoic Membrane (CAM) Assay and on Tumor and Endothelial Cell Proliferation.

Marks

Shi

Fry

et al. 2002

Biological & Pharmaceutical Bulletin

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“…20 The molecular form of thalidomide derivatives responsible for its antimyeloma efficacy, whether hydrolysis products or metabolites, is another unsolved dilemma. 10,21,22 We have used the myelomatous severe combined immunodeficiency-human (SCID-hu) model to further investigate the antimyeloma efficacy of thalidomide. In the SCID-hu model, fresh human myeloma cells grow in, interact with, and depend on a human microenvironment, as well as produce typical myeloma manifestations.…”

Section: Introductionmentioning

confidence: 99%

Antimyeloma efficacy of thalidomide in the SCID-hu model

Yaccoby

Johnson

Mahaffey

et al. 2002

Blood

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To determine the mechanism of thalidomide's antimyeloma efficacy, we studied the drug's activity in our severe combined immunodeficiency-human (SCIDhu) host system for primary human myeloma. In this model, tumor cells interact with the human microenvironment to produce typical myeloma manifestations in the hosts, including stimulation of neoangiogenesis. Because mice are not able to metabolize thalidomide efficiently, SCID-hu mice received implants of fetal human liver fragments under the renal capsule in addition to subcutaneous implants of the fetal human bone. Myeloma cell growth in these mice was similar to their growth in hosts without liver implant, as assessed by change in levels of circulating human immunoglobulins and by histologic examinations. Thalidomide given daily by peritoneal injection significantly inhibited myeloma growth in 7 of 8 experiments, each with myeloma cells from a different patient, in hosts implanted with human liver. In contrast, thalidomide exerted an antimyeloma effect only in 1 of 10 mice without liver implants. Microvessel density in the untreated controls was higher than in thalidomide-responsive hosts but not different from nonresponsive ones. Expression of vascular endothelial growth factor by myeloma cells and by other cells in the human bone, determined immunohistochemically, was not affected by thalidomide treatment in any experiment. Our study suggests that thalidomide metabolism is required for its antimyeloma efficacy. Although response to thalidomide was strongly associated with decreased microvessel density, we were unable to conclude whether reduced microvessel density is a primary result of thalidomide's antiangiogenic activity or is secondary to a lessened tumor burden. (Blood. 2002;100:4162-4168)

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“…The formation of 5,6-dihydroxythalidomide was also reported, with CYP2C19 identified as responsible for the hydroxylation of Thal in humans. Another study (Eriksson et al, 1998) has compared the formation of hydroxylated metabolites in vitro using human S9 liver fractions and in vivo in healthy human volunteers: both 5-OH Thal and cis-5Ј-OH Thal were formed in vitro but only cis-5Ј-OH Thal was detected in vivo. However, Teo et al, (2000) did not detect any metabolites after incubating Thal with human liver microsomes or in the plasma of patients with Hansen's disease, although trace amounts of 5-OH Thal were detected in urine.…”

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confidence: 99%

Metabolism of Thalidomide in Liver Microsomes of Mice, Rabbits, and Humans

Lu¹,

Helsby²,

Palmer³

et al. 2004

J Pharmacol Exp Ther

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Thalidomide is increasingly important in clinical treatment, not only of various inflammatory conditions but also in multiple myeloma and other malignancies. Moreover, the metabolism of thalidomide varies considerably among different species, indicating a need to understand its mechanistic basis. Our previous in vivo studies showed the plasma half-life of thalidomide to be much shorter in mice than in humans, with rabbits showing intermediate values. We were unable to detect hydroxylated thalidomide metabolites in humans and suggested that interspecies differences in thalidomide hydroxylation might account for the differences in plasma half-life. We sought here to establish whether these species differences in the formation of hydroxylated thalidomide metabolites could be discerned from in vitro studies. Liver microsomes of mice, rabbit, and human donors were incubated with thalidomide and analyzed using liquid chromatography-mass spectrometry. Hydrolysis products were detected for all three species, and the rates of formation were similar to those for spontaneous hydrolysis, except in rabbits where phthaloylisoglutamine formation increased linearly with microsomal enzyme concentration. Multiple hydroxylation products were detected, including three dihydroxylated metabolites not observed in vivo. Thalidomide-5-O-glucuronide, detected in vivo, was absent in vitro. The amount of 5-hydroxythalidomide formed was high in mice, lower in rabbits, and barely detectable in humans. We conclude that major interspecies differences in hepatic metabolism of thalidomide relate closely to the rate of in vivo metabolite formation. The very low rate of in vitro and in vivo hydroxylation in humans strongly suggests that thalidomide hydroxylation is not a requirement for clinical anticancer activity.Thalidomide (␣-phthalimidoglutarimide, Thal), despite its teratogenicity (McBride, 1961;Lenz, 1962), is attracting increasing clinical interest, initially as an anti-inflammatory agent (Sheskin, 1965;Zwingenberger and Wnendt, 1996;Calabrese and Fleischer, 2000) and more recently for the treatment of malignancies, particularly of multiple myeloma (Singhal et al., 1999;Eisen, 2000). Differences in metabolism among different species represent an important feature of its pharmacology. It has been suggested that Thal exerts its teratogenicity through an active metabolite, which is produced by human and rabbit liver microsome preparations but not by mouse liver microsomes (Gordon et al., 1981). After in vivo administration, Thal is both hydrolyzed chemically to a series of acid derivatives and hydroxylated by liver enzymes. In a previous study , we showed that the plasma half-life of Thal in mice was much shorter than that in patients with multiple myeloma, with New Zealand White rabbits showing an intermediate half-life. We also showed that hydroxylated metabolites were not detected in multiple myeloma patients but were found in C57/Bl/6 mice and rabbits, suggesting that relative rates of Thal hydroxylation in different species could...

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Hydroxylated Metabolites of Thalidomide: Formation In-vitro and In-vivo in Man

Cited by 53 publications

References 21 publications

Effects of Putative Hydroxylated Thalidomide Metabolites on Blood Vessel Density in the Chorioallantoic Membrane (CAM) Assay and on Tumor and Endothelial Cell Proliferation.

Effects of Putative Hydroxylated Thalidomide Metabolites on Blood Vessel Density in the Chorioallantoic Membrane (CAM) Assay and on Tumor and Endothelial Cell Proliferation.

Antimyeloma efficacy of thalidomide in the SCID-hu model

Metabolism of Thalidomide in Liver Microsomes of Mice, Rabbits, and Humans

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