CYP3A4, CYP2C9 and CYP2B6 expression and ifosfamide turnover in breast cancer tissue microsomes

Schmidt, Renate; Baumann, Frank; Knüpfer, Heike; Brauckhoff, Michael; Lc, Horn; Schönfelder, Martin; Köhler, Uwe; Preiss, R

doi:10.1038/sj.bjc.6601492

Cited by 37 publications

(31 citation statements)

References 16 publications

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“…CYP3A4 plays an important role in converting tamoxifen to N‐desmethyl‐4‐hydroxytamoxifen, which has a 30‐ to 100‐fold higher affinity for estrogen receptor than tamoxifen 34. CYP3A4, measured by immnuohistochemistry in normal and cancer breast tissue biopsies was found to be prognostic for patient response to docetaxel 35, 36 and by activity assay and western blot to correlate with ifosfamide activation 37. The presence of CYP3A4 in NAF provides a unique opportunity to screen for patients who are most likely to respond to prophylactic tamoxifen treatment.…”

Section: Resultsmentioning

confidence: 99%

Nipple aspirate fluid—A liquid biopsy for diagnosing breast health

Shaheed

Tait

Kyriacou

et al. 2017

Proteomics Clinical Apps

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PurposeNipple secretions are protein‐rich and a potential source of breast cancer biomarkers for breast cancer screening. Previous studies of specific proteins have shown limited correlation with clinicopathological features. Our aim, in this pilot study, was to investigate the intra‐ and interpatient protein composition of nipple secretions and the implications for their use as liquid biopsies.Experimental designMatched pairs of nipple discharge/nipple aspirate fluid (NAF, n = 15) were characterized for physicochemical properties and SDS‐PAGE. Four pairs were selected for semiquantitative proteomic profiling and trypsin‐digested peptides analyzed using 2D‐LC Orbitrap Fusion MS. The resulting data were subject to bioinformatics analysis and statistical evaluation for functional significance.ResultsA total of 1990 unique proteins were identified many of which are established cancer‐associated markers. Matched pairs shared the greatest similarity (average Pearson correlation coefficient of 0.94), but significant variations between individuals were observed.Conclusions and clinical relevanceThis was the most complete proteomic study of nipple discharge/nipple aspirate fluid to date providing a valuable source for biomarker discovery. The high level of milk proteins in healthy volunteer samples compared to the cancer patients was associated with galactorrhoea. Using matched pairs increased confidence in patient‐specific protein levels but changes relating to cancer stage require investigation of a larger cohort.

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Section: Resultsmentioning

confidence: 99%

Nipple aspirate fluid—A liquid biopsy for diagnosing breast health

Shaheed

Tait

Kyriacou

et al. 2017

Proteomics Clinical Apps

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“…More recent studies have shown that tumor cells also express drug-metabolizing P450 enzymes, including CYP2B6 (Nakajima et al, 1996;Standop et al, 2003) and CYP3A4 (Huang et al, 1996;Murray et al, 1999;Schmidt et al, 2004). The levels of tumor cell P450 are low but may nevertheless be an important factor in the metabolism and activity of these anticancer agents.…”

Section: Discussionmentioning

confidence: 99%

ENANTIOSELECTIVE METABOLISM AND CYTOTOXICITY OFR-IFOSFAMIDE ANDS-IFOSFAMIDE BY TUMOR CELL-EXPRESSED CYTOCHROMES P450

Chen¹,

Jounaïdi²,

Waxman³

2005

Drug Metab Dispos

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ABSTRACT:The anticancer prodrug ifosfamide (IFA) contains a chiral phosphorous atom and is administered in the clinic as a racemic mixture of R-IFA and S-IFA. Hepatic cytochrome P450 (P450) enzymes exhibit enantioselective preferences in the metabolism of R-IFA and S-IFA; however, the impact of this selectivity on P450-dependent anticancer activity is not known. Presently, the metabolism and cytotoxicity of R-IFA and S-IFA were determined in 9L gliosarcoma and Chinese hamster ovary tumor cells expressing an IFA-activating P450 enzyme and by in vitro steady-state kinetic analysis using cDNA-expressed P450 enzymes. Tumor cells expressing P450 enzyme CYP3A4 were the most sensitive to R-IFA cytotoxicity, whereas tumor cells expressing CYP2B1 or CYP2B6 were most sensitive to cyclophosphamide (CPA), an isomer of IFA. Correspondingly, CYP3A4-expressing cells and cDNA-expressed CYP3A4 metabolized R-IFA to yield the active, 4-hydroxylated metabolite at a 2-to 3-fold higher rate than they metabolized S-IFA or CPA. CYP2B cells and cDNA-expressed CYP2B enzymes metabolized CPA almost exclusively by 4-hydroxylation, whereas R-IFA and S-IFA were substantially converted to inactive, N-dechloroethylated metabolites. Further investigation revealed that CYP3A1, a rat enzyme, exhibited superior kinetic properties compared with the human enzyme CYP3A4, with R-IFA and S-IFA both metabolized with high catalytic efficiency by 4-hydroxylation and with a K m value of 200 M, ϳ5-fold lower than CYP3A4. Based on these kinetic parameters and metabolic profiles, R-IFA is expected to exert greater anticancer activity than S-IFA or CPA against tumors that express CYP3A enzymes, whereas tumors expressing CYP2B enzymes may be more sensitive to CPA treatment.Ifosfamide (IFA) and its structural isomer cyclophosphamide (CPA) are clinically effective anticancer alkylating agent prodrugs used to treat a broad range of neoplasms. Both prodrugs are activated in the liver by a cytochrome P450-catalyzed 4-hydroxylation reaction. The primary 4-hydroxy metabolite exists in equilibrium with the ring-opened aldo(iso)phosphamide, which undergoes ␤-elimination to yield the therapeutically active, DNA cross-linking metabolite (iso)phosphoramide mustard and acrolein, a reactive aldehyde (Sladek, 1988;Zalupski and Baker, 1988). An alternative, P450-catalyzed N-dechloroethylation reaction inactivates the parent drug and generates the neurotoxic and nephrotoxic byproduct chloroacetaldehyde (CAA). Although CPA and IFA are very similar in chemical structure and mechanism of action, they differ strikingly with respect to their pharmacokinetic and pharmacodynamic properties. CPA is metabolized predominantly by 4-hydroxylation, catalyzed by CYP2B and CYP2C enzymes, whereas IFA undergoes extensive N-dechloroethylation, catalyzed by CYP2B and CYP3A enzymes (Huang and Waxman, 1999;Roy et al., 1999b;Chen et al., 2004). The formation of CAA as a major byproduct of IFA N-dechloroethylation is associated with the neurotoxicity and urotoxicity seen in patients treated with IFA b...

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“…This profile fits our objective criteria defined by other experimental observations. ROS production is mediated through specific isozymes of CYP450 (29,42,43). In particular, the isozyme, CYP2C9, has been shown to responsible for ROS in several cell types (44).…”

Section: Dsbs and Ssbs (mentioning

confidence: 99%

MYC Can Induce DNA Breaks In vivo and In vitro Independent of Reactive Oxygen Species

Ray¹,

Atkuri²,

Deb-Basu³

et al. 2006

Cancer Research

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MYC overexpression is thought to initiate tumorigenesis by inducing cellular proliferation and growth and to be restrained from causing tumorigenesis by inducing cell cycle arrest, cellular senescence, and/or apoptosis. Here we show that MYC can induce DNA breaks both in vitro and in vivo independent of increased production of reactive oxygen species (ROS). We provide an insight into the specific circumstances under which MYC generates ROS in vitro and propose a possible mechanism. We found that MYC induces DNA double-strand breaks (DSBs) independent of ROS production in murine lymphocytes in vivo as well as in normal human foreskin fibroblasts (NHFs) in vitro in normal (10%) serum, as measured by ;H2AX staining. However, NHFs cultured in vitro in low serum (0.05%) and/or ambient oxygen saturation resulted in ROS-associated oxidative damage and DNA single-strand breaks (SSBs), as measured by Ape-1 staining. In NHFs cultured in low versus normal serum, MYC induced increased expression of CYP2C9, a gene product well known to be associated with ROS production. Specific inhibition of CYP2C9 by small interfering RNA was shown to partially inhibit MYC-induced ROS production. Hence, MYC overexpression can induce ROS and SSBs under some conditions, but generally induces widespread DSBs in vivo and in vitro independent of ROS production. (Cancer Res 2006; 66(13): 6598-605)

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CYP3A4, CYP2C9 and CYP2B6 expression and ifosfamide turnover in breast cancer tissue microsomes

Cited by 37 publications

References 16 publications

Nipple aspirate fluid—A liquid biopsy for diagnosing breast health

Nipple aspirate fluid—A liquid biopsy for diagnosing breast health

ENANTIOSELECTIVE METABOLISM AND CYTOTOXICITY OFR-IFOSFAMIDE ANDS-IFOSFAMIDE BY TUMOR CELL-EXPRESSED CYTOCHROMES P450

MYC Can Induce DNA Breaks In vivo and In vitro Independent of Reactive Oxygen Species

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