1
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Lee O, Bazzi LA, Xu Y, Pearson E, Wang M, Hosseini O, Akasha AM, Choi JN, Karlan S, Pilewskie M, Kocherginsky M, Benante K, Helland T, Mellgren G, Dimond E, Perloff M, Heckman-Stoddard BM, Khan SA. A randomized Phase I pre-operative window trial of transdermal endoxifen in women planning mastectomy: Evaluation of dermal safety, intra-mammary drug distribution, and biologic effects. Biomed Pharmacother 2024; 171:116105. [PMID: 38171245 DOI: 10.1016/j.biopha.2023.116105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/17/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024] Open
Abstract
Breast cancer prevention only requires local exposure of the breast to active drug. However, oral preventive agents entail systemic exposure, causing adverse effects that limit acceptance by high-risk women. Drug-delivery through the breast skin is an attractive option, but requires demonstration of dermal safety and drug distribution throughout the breast. We formulated the tamoxifen metabolite (E/Z)-endoxifen for transdermal delivery and tested it in a placebo-controlled, double-blinded Phase I trial with dose escalation from 10 to 20 mg daily. The primary endpoint was dermal toxicity. Thirty-two women planning mastectomy were randomized (2:1) to endoxifen-gel or placebo-gel applied to both breasts for 3-5 weeks. Both doses of endoxifen-gel incurred no dermal or systemic toxicity compared to placebo. All endoxifen-treated breasts contained the drug at each of five sampling locations; the median per-person tissue concentration in the treated participants was 0.6 ng/g (IQR 0.4-1.6), significantly higher (p < 0.001) than the median plasma concentration (0.2 ng/mL, IQR 0.2-0.2). The median ratio of the more potent (Z)-isomer to (E)-isomer at each breast location was 1.50 (IQR 0.96-2.54, p < 0.05). No discernible effects of breast size or adiposity on tissue concentrations were observed. At the endoxifen doses and duration used, and the tissue concentration achieved, we observed a non-significant overall reduction of tumor proliferation (Ki67 LI) and significant downregulation of gene signatures known to promote cancer invasion (FN1, SERPINH1, PLOD2, PDGFA, ITGAV) (p = 0.03). Transdermal endoxifen is an important potential breast cancer prevention agent but formulations with better dermal penetration are needed.
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Affiliation(s)
- Oukseub Lee
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Latifa A Bazzi
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Yanfei Xu
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Erik Pearson
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Minhua Wang
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Omid Hosseini
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Azza M Akasha
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jennifer Nam Choi
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Scott Karlan
- Saul and Joyce Brandman Breast Center, Cedars-Sinai Medical Center, West Hollywood, CA, USA
| | | | - Masha Kocherginsky
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kelly Benante
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Thomas Helland
- Hormone Laboratory, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway; Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Gunnar Mellgren
- Hormone Laboratory, Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway; Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Eileen Dimond
- Division of Cancer Prevention, National Cancer Institute, Bethesda, MD, USA
| | - Marjorie Perloff
- Division of Cancer Prevention, National Cancer Institute, Bethesda, MD, USA
| | | | - Seema A Khan
- Department of Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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2
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Jayaraman S, Wu X, Kalari KR, Tang X, Kuffel MJ, Bruinsma ES, Jalali S, Peterson KL, Correia C, Kudgus RA, Kaufmann SH, Renuse S, Ingle JN, Reid JM, Ames MM, Fields AP, Schellenberg MJ, Hawse JR, Pandey A, Goetz MP. Endoxifen downregulates AKT phosphorylation through protein kinase C beta 1 inhibition in ERα+ breast cancer. NPJ Breast Cancer 2023; 9:101. [PMID: 38114522 PMCID: PMC10730845 DOI: 10.1038/s41523-023-00606-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023] Open
Abstract
Endoxifen, a secondary tamoxifen metabolite, is a potent antiestrogen exhibiting estrogen receptor alpha (ERα) binding at nanomolar concentrations. Phase I/II clinical trials identified clinical activity of Z-endoxifen (ENDX), in endocrine-refractory metastatic breast cancer as well as ERα+ solid tumors, raising the possibility that ENDX may have a second, ERα-independent, mechanism of action. An unbiased mass spectrometry approach revealed that ENDX concentrations achieved clinically with direct ENDX administration (5 µM), but not low concentrations observed during tamoxifen treatment (<0.1 µM), profoundly altered the phosphoproteome of the aromatase expressing MCF7AC1 cells with limited impact on the total proteome. Computational analysis revealed protein kinase C beta (PKCβ) and protein kinase B alpha or AKT1 as potential kinases responsible for mediating ENDX effects on protein phosphorylation. ENDX more potently inhibited PKCβ1 kinase activity compared to other PKC isoforms, and ENDX binding to PKCβ1 was confirmed using Surface Plasma Resonance. Under conditions that activated PKC/AKT signaling, ENDX induced PKCβ1 degradation, attenuated PKCβ1-activated AKTSer473 phosphorylation, diminished AKT substrate phosphorylation, and induced apoptosis. ENDX's effects on AKT were phenocopied by siRNA-mediated PKCβ1 knockdown or treatment with the pan-AKT inhibitor, MK-2206, while overexpression of constitutively active AKT diminished ENDX-induced apoptosis. These findings, which identify PKCβ1 as an ENDX target, indicate that PKCβ1/ENDX interactions suppress AKT signaling and induce apoptosis in breast cancer.
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Affiliation(s)
| | - Xinyan Wu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Krishna R Kalari
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Xiaojia Tang
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Mary J Kuffel
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Elizabeth S Bruinsma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Shahrzad Jalali
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | | | - Cristina Correia
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Rachel A Kudgus
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Scott H Kaufmann
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Santosh Renuse
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, 55905, USA
| | - James N Ingle
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Joel M Reid
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Matthew M Ames
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Alan P Fields
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Jacksonville, FL, 32224, USA
| | - Matthew J Schellenberg
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Cancer Biology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Akhilesh Pandey
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Matthew P Goetz
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.
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3
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Lee O, Wang M, Hosseini O, Bosland MC, Muzzio M, Helenowski I, Khan SA. Z-Endoxifen prevents aggressive mammary cancers in mice by inhibiting cell proliferation and creating a tumor suppressive microenvironment. Biomed Pharmacother 2023; 162:114607. [PMID: 37001185 DOI: 10.1016/j.biopha.2023.114607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/31/2023] Open
Abstract
Aggressive estrogen receptor (ER) positive breast cancer is frequently tamoxifen-resistant; alternative endocrine approaches exist for therapy, but not for prevention, particularly in premenopausal women. We examined the efficacy of the selective ER modulator (Z-endoxifen) as monotherapy and in combination with the selective progesterone receptor modulators (onapristone and ulipristal acetate) in the tamoxifen-insensitive C3(1)/SV40TAg mouse mammary tumorigenesis model. Unlike tamoxifen at human equivalent dose (HED) 101 mg/day, endoxifen at HED 24 mg/day significantly increased latency and reduced tumor growth relative to untreated controls. Ulipristal acetate (UPA) at HED 81 mg/day also significantly increased latency however failed to inhibit tumor growth, while onapristone (HED 98 mg/day) had no tumor prevention efficacy in this model. Addition of UPA to endoxifen did not enhance preventive efficacy over endoxifen alone. The expression of genes associated with cell cycle, cell proliferation and extracellular matrix remodeling was similarly repressed by endoxifen and UPA however only endoxifen significantly downregulated prominent genes associated with poor prognosis (Col11a1, Il17b, Pdgfa, Tnfrsf11a). Our results indicate that endoxifen can prevent breast cancers, even when tamoxifen-resistant, through its role in favorable tissue remodeling and immunomodulation.
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Affiliation(s)
- Oukseub Lee
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
| | - Minhua Wang
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Omid Hosseini
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Maarten C Bosland
- Department of Pathology, University of Illinois at Chicago, Chicago, IL, USA
| | - Miguel Muzzio
- Analytical Chemistry Division, Illinois Institute of Technology Research Institute, Chicago, IL, USA
| | - Irene Helenowski
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Seema A Khan
- Department of Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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4
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Jayaraman S, Reid JM, Hawse JR, Goetz MP. Endoxifen, an Estrogen Receptor Targeted Therapy: From Bench to Bedside. Endocrinology 2021; 162:6364076. [PMID: 34480554 PMCID: PMC8787422 DOI: 10.1210/endocr/bqab191] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 11/19/2022]
Abstract
The selective estrogen receptor (ER) modulator, tamoxifen, is the only endocrine agent with approvals for both the prevention and treatment of premenopausal and postmenopausal estrogen-receptor positive breast cancer as well as for the treatment of male breast cancer. Endoxifen, a secondary metabolite resulting from CYP2D6-dependent biotransformation of the primary tamoxifen metabolite, N-desmethyltamoxifen (NDT), is a more potent antiestrogen than either NDT or the parent drug, tamoxifen. However, endoxifen's antitumor effects may be related to additional molecular mechanisms of action, apart from its effects on ER. In phase 1/2 clinical studies, the efficacy of Z-endoxifen, the active isomer of endoxifen, was evaluated in patients with endocrine-refractory metastatic breast cancer as well as in patients with gynecologic, desmoid, and hormone-receptor positive solid tumors, and demonstrated substantial oral bioavailability and promising antitumor activity. Apart from its potent anticancer effects, Z-endoxifen appears to result in similar or even greater bone agonistic effects while resulting in little or no endometrial proliferative effects compared with tamoxifen. In this review, we summarize the preclinical and clinical studies evaluating endoxifen in the context of breast and other solid tumors, the potential benefits of endoxifen in bone, as well as its emerging role as an antimanic agent in bipolar disorder. In total, the summarized body of literature provides compelling arguments for the ongoing development of Z-endoxifen as a novel drug for multiple indications.
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Affiliation(s)
| | - Joel M Reid
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew P Goetz
- Correspondence: Matthew P. Goetz, MD, Department of Medical Oncology and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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5
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Braal CL, Jager A, Hoop EOD, Westenberg JD, Lommen KMWT, de Bruijn P, Vastbinder MB, van Rossum-Schornagel QC, Thijs-Visser MF, van Alphen RJ, Struik LEM, Zuetenhorst HJM, Mathijssen RHJ, Koolen SLW. Therapeutic Drug Monitoring of Endoxifen for Tamoxifen Precision Dosing: Feasible in Patients with Hormone-Sensitive Breast Cancer. Clin Pharmacokinet 2021; 61:527-537. [PMID: 34786650 PMCID: PMC8975771 DOI: 10.1007/s40262-021-01077-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2021] [Indexed: 02/08/2023]
Abstract
Background Endoxifen is the most important active metabolite of tamoxifen. Several retrospective studies have suggested a minimal or threshold endoxifen systemic concentration of 14–16 nM is required for a lower recurrence rate. The aim of this study was to investigate the feasibility of reaching a predefined endoxifen level of ≥ 16 nM (5.97 ng/mL) over time using therapeutic drug monitoring (TDM). Methods This prospective open-label intervention study enrolled patients who started treatment with a standard dose of tamoxifen 20 mg once daily for early breast cancer. An outpatient visit was combined with a TDM sample at 3, 4.5, and 6 months after initiation of the tamoxifen treatment. The tamoxifen dose was escalated to a maximum of 40 mg if patients had an endoxifen concentration < 16 nM. The primary endpoint of the study was the percentage of patients with an endoxifen level ≥ 16 nM at 6 months after the start of therapy compared with historical data, in other words, 80% of patients with endoxifen levels ≥ 16 nM with standard therapy. Results In total, 145 patients were included. After 6 months, 89% of the patients had endoxifen levels ≥ 16 nM, compared with a literature-based 80% of patients with endoxifen levels ≥ 16 nM at baseline (95% confidence interval 82–94; P = 0.007). In patients with an affected CYP2D6 allele, it was not always feasible to reach the predefined endoxifen level of ≥ 16 nM. No increase in tamoxifen-related adverse events was reported after dose escalation. Conclusion This study demonstrated that it is feasible to increase the percentage of patients with endoxifen levels ≥ 16 nM using TDM. TDM is a safe strategy that offers the possibility of nearly halving the number of patients with endoxifen levels < 16 nM.
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Affiliation(s)
- C Louwrens Braal
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Agnes Jager
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Esther Oomen-de Hoop
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Justin D Westenberg
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Koen M W T Lommen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Peter de Bruijn
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Mijntje B Vastbinder
- Department of Internal Medicine, IJsselland Hospital, Capelle aan den IJssel, The Netherlands
| | | | - Martine F Thijs-Visser
- Department of Internal Medicine, Ikazia Hospital, Rotterdam, The Netherlands.,Department of Internal Medicine, Spijkenisse MC, Spijkenisse, The Netherlands
| | - Robbert J van Alphen
- Department of Internal Medicine, Elisabeth Tweesteden Hospital, Tilburg, The Netherlands
| | - Liesbeth E M Struik
- Department of Internal Medicine, Ikazia Hospital, Rotterdam, The Netherlands
| | | | - Ron H J Mathijssen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Stijn L W Koolen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands. .,Department of Hospital Pharmacy, Erasmus University Medical Center, Rotterdam, The Netherlands.
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6
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Jones CJ, Subramaniam M, Emch MJ, Bruinsma ES, Ingle JN, Goetz MP, Hawse JR. Development and Characterization of Novel Endoxifen-Resistant Breast Cancer Cell Lines Highlight Numerous Differences from Tamoxifen-Resistant Models. Mol Cancer Res 2021; 19:1026-1039. [PMID: 33627502 DOI: 10.1158/1541-7786.mcr-20-0872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/25/2021] [Accepted: 02/19/2021] [Indexed: 12/24/2022]
Abstract
Despite the availability of drugs that target ERα-positive breast cancer, resistance commonly occurs, resulting in relapse, metastasis, and death. Tamoxifen remains the most commonly-prescribed endocrine therapy worldwide, and "tamoxifen resistance" has been extensively studied. However, little consideration has been given to the role of endoxifen, the most abundant active tamoxifen metabolite detected in patients, in driving resistance mechanisms. Endoxifen functions differently from the parent drug and other primary metabolites, including 4-hydroxy-tamoxifen (4HT). Many studies have shown that patients who extensively metabolize tamoxifen into endoxifen have superior outcomes relative to patients who do not, supporting a primary role for endoxifen in driving tamoxifen responses. Therefore, "tamoxifen resistance" may be better modeled by "endoxifen resistance" for some patients. Here, we report the development of novel endoxifen-resistant breast cancer cell lines and have extensively compared these models to 4HT and fulvestrant (ICI)-resistant models. Endoxifen-resistant cells were phenotypically and molecularly distinct from 4HT-resistant cells and more closely resembled ICI-resistant cells overall. Specifically, endoxifen resistance was associated with ERα and PR loss, estrogen insensitivity, unique gene signatures, and striking resistance to most FDA-approved second- and third-line therapies. Given these findings, and the importance of endoxifen in the efficacy of tamoxifen therapy, our data indicate that endoxifen-resistant models may be more clinically relevant than existing models and suggest that a better understanding of endoxifen resistance could substantially improve patient care. IMPLICATIONS: Here we report on the development and characterization of the first endoxifen-resistant models and demonstrate that endoxifen resistance may better model tamoxifen resistance in a subset of patients.
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Affiliation(s)
- Calley J Jones
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | | | - Michael J Emch
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Elizabeth S Bruinsma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - James N Ingle
- Department of Oncology, Mayo Clinic, Rochester, Minnesota
| | | | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
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7
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Takebe N, Coyne GO, Kummar S, Collins J, Reid JM, Piekarz R, Moore N, Juwara L, Johnson BC, Bishop R, Lin FI, Mena E, Choyke PL, Lindenberg ML, Rubinstein LV, Bonilla CM, Goetz MP, Ames MM, McGovern RM, Streicher H, Covey JM, Doroshow JH, Chen AP. Phase 1 study of Z-endoxifen in patients with advanced gynecologic, desmoid, and hormone receptor-positive solid tumors. Oncotarget 2021; 12:268-277. [PMID: 33659039 PMCID: PMC7899551 DOI: 10.18632/oncotarget.27887] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/19/2021] [Indexed: 12/21/2022] Open
Abstract
Background: Differential responses to tamoxifen may be due to inter-patient variability in tamoxifen metabolism into pharmacologically active Z-endoxifen. Z-endoxifen administration was anticipated to bypass these variations, increasing active drug levels, and potentially benefitting patients responding sub-optimally to tamoxifen. Materials and Methods: Patients with treatment-refractory gynecologic malignancies, desmoid tumors, or hormone receptor-positive solid tumors took oral Z-endoxifen daily with a 3+3 phase 1 dose escalation format over 8 dose levels (DLs). Safety, pharmacokinetics/pharmacodynamics, and clinical outcomes were evaluated. Results: Thirty-four of 40 patients were evaluable. No maximum tolerated dose was established. DL8, 360 mg/day, was used for the expansion phase and is higher than doses administered in any previous study; it also yielded higher plasma Z-endoxifen concentrations. Three patients had partial responses and 8 had prolonged stable disease (≥ 6 cycles); 44.4% (8/18) of patients at dose levels 6–8 achieved one of these outcomes. Six patients who progressed after tamoxifen therapy experienced partial response or stable disease for ≥ 6 cycles with Z-endoxifen; one with desmoid tumor remains on study after 62 cycles (nearly 5 years). Conclusions: Evidence of antitumor activity and prolonged stable disease are achieved with Z-endoxifen despite prior tamoxifen therapy, supporting further study of Z-endoxifen, particularly in patients with desmoid tumors.
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Affiliation(s)
- Naoko Takebe
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Shivaani Kummar
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA.,Division of Hematology and Medical Oncology, Knight Cancer Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jerry Collins
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Joel M Reid
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Richard Piekarz
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Nancy Moore
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Lamin Juwara
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Barry C Johnson
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Rachel Bishop
- Consult Services Section, National Eye Institute, Bethesda, MD 20892, USA
| | - Frank I Lin
- Molecular Imaging Program, National Cancer Institute, Bethesda, MD 20892, USA
| | - Esther Mena
- Molecular Imaging Program, National Cancer Institute, Bethesda, MD 20892, USA
| | - Peter L Choyke
- Molecular Imaging Program, National Cancer Institute, Bethesda, MD 20892, USA
| | - M Liza Lindenberg
- Molecular Imaging Program, National Cancer Institute, Bethesda, MD 20892, USA
| | - Larry V Rubinstein
- Biometric Research Program, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Matthew P Goetz
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew M Ames
- Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Howard Streicher
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - Joseph M Covey
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
| | - James H Doroshow
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA.,Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Alice P Chen
- Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, MD 20892, USA
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8
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Sanchez-Spitman AB, Moes DJAR, Swen JJ, Dezentjé VO, Lambrechts D, Neven P, Gelderblom H, Guchelaar HJ. Exposure-response analysis of endoxifen serum concentrations in early-breast cancer. Cancer Chemother Pharmacol 2020; 85:1141-1152. [PMID: 32468081 PMCID: PMC7305085 DOI: 10.1007/s00280-020-04089-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/19/2020] [Indexed: 12/14/2022]
Abstract
Purpose
Tamoxifen is part of endocrine therapy in breast cancer treatment. Studies have indicated the use of endoxifen concentrations, tamoxifen active metabolite, to guide tamoxifen efficacy. Three endoxifen thresholds have been suggested (5.9 ng/ml, 5.2 ng/ml and 3.3 ng/ml) for therapeutic drug monitoring (TDM). Our aim was to validate these thresholds and to examine endoxifen exposure with clinical outcome in early-breast cancer patients using tamoxifen. Methods Data from 667 patients from the CYPTAM study (NTR1509) were available. Patients were stratified (above or below), according to the endoxifen threshold values for tamoxifen efficacy and tested by Cox regression. Logistic regressions to estimate the probability of relapse and tamoxifen discontinuation were performed. Results None of the thresholds showed a statistically significant difference in relapse-free survival: 5.2 ng/ml threshold: hazard ratio (HR): 2.545, 95% confidence interval (CI) 0.912–7.096, p value: 0.074; 3.3 ng/ml threshold: HR: 0.728; 95% CI 0.421–1.258, p value: 0.255. Logistic regression did not show a statistically significant association between the risk of relapse (odds ratio (OR): 0.971 (95% CI 0.923–1.021, p value: 0.248) and the risk for tamoxifen discontinuation (OR: 1.006 95% CI 0.961–1.053, p value: 0.798) with endoxifen concentrations. Conclusion Our findings do not confirm the endoxifen threshold values for TDM nor does it allow definition of a novel threshold. These findings indicate a limited value of TDM to guide tamoxifen efficacy.
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Affiliation(s)
- Anabel Beatriz Sanchez-Spitman
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Albinusdreef 2, 2300 RC, Leiden, The Netherlands.,Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
| | - Dirk-Jan A R Moes
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Albinusdreef 2, 2300 RC, Leiden, The Netherlands.,Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
| | - Jesse J Swen
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Albinusdreef 2, 2300 RC, Leiden, The Netherlands.,Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
| | - Vincent O Dezentjé
- Department of Medical Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - Diether Lambrechts
- Center for Cancer Biology, VIB, Leuven, Belgium.,Laboratory for Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Patrick Neven
- Department of Medical Oncology, University Hospital Leuven, Leuven, Belgium
| | - Hans Gelderblom
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands.,Department of Medical Oncology, Leiden University Medical Center, Leiden, The Netherlands
| | - Henk-Jan Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Albinusdreef 2, 2300 RC, Leiden, The Netherlands. .,Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands.
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9
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Arafah A, Yakout K, Rehman MU, Mohammed Alsharif A, AlJawadi MH, Al-Omar HA. Prevalence of the co-prescription of tamoxifen and CYP2D6 inhibitors in Saudi population: A cross sectional study. Saudi Pharm J 2020; 28:440-444. [PMID: 32273802 PMCID: PMC7132831 DOI: 10.1016/j.jsps.2020.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 02/10/2020] [Indexed: 01/15/2023] Open
Abstract
Consumption of Cytochrome P450 2D6 (CYP2D6) inhibiting drugs along with tamoxifen treatment results in decrease in plasma concentration of endoxifen, the major active tamoxifen metabolite. Simultaneous use of CYP2D6 inhibitors, such as selective serotonin reuptake inhibitors (SSIs), as well as lesser tamoxifen adherence may negatively impact tamoxifen efficacy in patients with breast cancer. The objective of our study was to assess the co-prescription of CYP2D6 inhibitors and tamoxifen use and also to relate concomitant CYP2D6 inhibitor use and tamoxifen adherence to breast cancer in Riyadh, Saudi Arabia. All patients treated for breast cancer who had at least one tamoxifen prescription in their electronic medical records (EMRs) from June 2015 to June 2017 were included. Patients who had other adjuvant hormonal therapy were excluded from the study. In total, 499 patients (25 males and 474 females) with breast cancer using tamoxifen were included. Our study was purely observational study revealed that prescription of weak inhibitors with tamoxifen increased in the second year as opposed to decrease in the prescription of strong inhibitors. Also, a substantial percentage of patient population were found to be non-adherent to the tamoxifen therapy in this study.
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Affiliation(s)
- Azher Arafah
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
- Corresponding author.
| | - Khalid Yakout
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
- College of Pharmacy, AlMaarefa University, Dariyah, PO Box No 71666, Riyadh 11597, Saudi Arabia
| | - Muneeb U. Rehman
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
| | - Ammar Mohammed Alsharif
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
- SERVIER Saudi Arabia, AlSalama District, PO Box No 112744, Jeddah 21371, Saudi Arabia
| | - Mohammad H. AlJawadi
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
| | - Hussain Abdulrahman Al-Omar
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, PO Box No 2457, Riyadh 11451, Saudi Arabia
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10
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Hennig EE, Piątkowska M, Goryca K, Pośpiech E, Paziewska A, Karczmarski J, Kluska A, Brewczyńska E, Ostrowski J. Non- CYP2D6 Variants Selected by a GWAS Improve the Prediction of Impaired Tamoxifen Metabolism in Patients with Breast Cancer. J Clin Med 2019; 8:jcm8081087. [PMID: 31344832 PMCID: PMC6722498 DOI: 10.3390/jcm8081087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/28/2019] [Accepted: 07/10/2019] [Indexed: 12/25/2022] Open
Abstract
A certain minimum plasma concentration of (Z)-endoxifen is presumably required for breast cancer patients to benefit from tamoxifen therapy. In this study, we searched for DNA variants that could aid in the prediction of risk for insufficient (Z)-endoxifen exposure. A metabolic ratio (MR) corresponding to the (Z)-endoxifen efficacy threshold level was adopted as a cutoff value for a genome-wide association study comprised of 287 breast cancer patients. Multivariate regression was used to preselect variables exhibiting an independent impact on the MR and develop models to predict below-threshold MR values. In total, 15 single-nucleotide polymorphisms (SNPs) were significantly associated with below-threshold MR values. The strongest association was with rs8138080 (WBP2NL). Two alternative models for MR prediction were developed. The predictive accuracy of Model 1, including rs7245, rs6950784, rs1320308, and the CYP2D6 genotype, was considerably higher than that of the CYP2D6 genotype alone (AUC 0.879 vs 0.758). Model 2, which was developed using the same three SNPs as for Model 1 plus rs8138080, appeared as an interesting alternative to the full CYP2D6 genotype testing. In conclusion, the four novel SNPs, tested alone or in combination with the CYP2D6 genotype, improved the prediction of impaired tamoxifen-to-endoxifen metabolism, potentially allowing for treatment optimization.
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Affiliation(s)
- Ewa E Hennig
- Department of Gastroenterology, Hepatology and Clinical Oncology, Centre of Postgraduate Medical Education, 01-813 Warsaw, Poland.
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland.
| | - Magdalena Piątkowska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
| | - Krzysztof Goryca
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
| | - Ewelina Pośpiech
- Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland
| | - Agnieszka Paziewska
- Department of Gastroenterology, Hepatology and Clinical Oncology, Centre of Postgraduate Medical Education, 01-813 Warsaw, Poland
| | - Jakub Karczmarski
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
| | - Anna Kluska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
| | - Elżbieta Brewczyńska
- Department of Breast Cancer and Reconstructive Surgery, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
| | - Jerzy Ostrowski
- Department of Gastroenterology, Hepatology and Clinical Oncology, Centre of Postgraduate Medical Education, 01-813 Warsaw, Poland
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, 02-781 Warsaw, Poland
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11
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Sanchez-Spitman A, Swen J, Dezentje V, Moes D, Gelderblom H, Guchelaar H. Clinical pharmacokinetics and pharmacogenetics of tamoxifen and endoxifen. Expert Rev Clin Pharmacol 2019; 12:523-536. [DOI: 10.1080/17512433.2019.1610390] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- A.B. Sanchez-Spitman
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - J.J. Swen
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - V.O. Dezentje
- Department of Medical Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek, Amsterdam, The Netherlands
| | - D.J.A.R. Moes
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - H. Gelderblom
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Medical Oncology, Leiden University Medical Center, Leiden, The Netherlands
| | - H.J. Guchelaar
- Leiden Network for Personalised Therapeutics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
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12
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Jansen LE, Teft WA, Rose RV, Lizotte DJ, Kim RB. CYP2D6 genotype and endoxifen plasma concentration do not predict hot flash severity during tamoxifen therapy. Breast Cancer Res Treat 2018; 171:701-708. [PMID: 29980881 DOI: 10.1007/s10549-018-4876-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE Tamoxifen is frequently prescribed to prevent breast cancer recurrence. Tamoxifen is a prodrug and requires bioactivation by CYP2D6. Tamoxifen use is often limited by adverse effects including severe hot flashes. There is paucity of prospectively collected data in terms of CYP2D6 genotype and measured tamoxifen, 4-hydroxytamoxifen and endoxifen concentrations in relation to hot flash severity during tamoxifen therapy. METHODS We conducted a longitudinal prospective study of breast cancer patients on tamoxifen (n = 410). At each visit, blood samples were collected, and patients completed a standardized hot flash survey (n = 1144) that reflected hot flash severity during the 7 days prior to the visit. Plasma concentrations of tamoxifen, 4-hydroxytamoxifen, and endoxifen were measured using liquid chromatography-tandem mass spectrometry and genotyping was carried out for CYP2D6. A linear mixed-effects regression analysis assessed the association of covariates in relation to the hot flash severity score (HFSS). RESULTS Median age at first assessment was 50 years with 61.9% of patients considered peri-menopausal. Most patients (92.2%) experienced hot flash symptoms with 51.0% having low HFSS (0-4) and 7.32% experiencing HFSS > 25. Age was significantly associated with hot flash severity, with patients aged 45-59 more likely to have higher HFSS. Neither duration of tamoxifen therapy nor observed tamoxifen, endoxifen and 4-hydroxy tamoxifen plasma concentration predicted hot flash severity. Genetic variation in CYP2D6 or CYP3A4 was not predictive of hot flash severity. CONCLUSIONS Hot flash severity during tamoxifen therapy can not be accounted for by CYP2D6 genotype or observed plasma concentration of tamoxifen, 4-hydroxytamoxifen, or endoxifen.
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Affiliation(s)
- Laura E Jansen
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada
| | - Wendy A Teft
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada
| | - Rhiannon V Rose
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5K5, Canada
| | - Daniel J Lizotte
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5K5, Canada
| | - Richard B Kim
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada. .,Department of Oncology, Western University, London, ON, N6A 5K5, Canada. .,Department of Medicine, LHSC-University Hospital, Room A-LL-152, 339 Windermere Road, London, ON, N6A 5A5, Canada.
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13
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Pharmacogenomics Guided-Personalization of Warfarin and Tamoxifen. J Pers Med 2017; 7:jpm7040020. [PMID: 29236081 PMCID: PMC5748632 DOI: 10.3390/jpm7040020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/23/2017] [Accepted: 12/07/2017] [Indexed: 02/07/2023] Open
Abstract
The use of pharmacogenomics to personalize drug therapy has been a long-sought goal for warfarin and tamoxifen. However, conflicting evidence has created reason for hesitation in recommending pharmacogenomics-guided care for both drugs. This review will provide a summary of the evidence to date on the association between cytochrome P450 enzymes and the clinical end points of warfarin and tamoxifen therapy. Further, highlighting the clinical experiences that we have gained over the past ten years of running a personalized medicine program, we will offer our perspectives on the utility and the limitations of pharmacogenomics-guided care for warfarin and tamoxifen therapy.
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14
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Reese JM, Bruinsma ES, Monroe DG, Negron V, Suman VJ, Ingle JN, Goetz MP, Hawse JR. ERβ inhibits cyclin dependent kinases 1 and 7 in triple negative breast cancer. Oncotarget 2017; 8:96506-96521. [PMID: 29228549 PMCID: PMC5722501 DOI: 10.18632/oncotarget.21787] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 09/16/2017] [Indexed: 12/31/2022] Open
Abstract
Triple negative breast cancer (TNBC), which comprises approximately 15% of all primary breast cancer diagnoses, lacks estrogen receptor alpha, progesterone receptor and human epidermal growth factor receptor 2 expression. However, we, and others, have demonstrated that approximately 30% of TNBCs express estrogen receptor beta (ERβ), a nuclear hormone receptor and potential drug target. Treatment of ERβ expressing MDA-MB-231 cells with estrogen or the ERβ selective agonist, LY500307, was shown to result in suppression of cell proliferation. This inhibitory effect was due to blockade of cell cycle progression. In vivo, estrogen treatment significantly repressed the growth of ERβ expressing MDA-MB-231 cell line xenografts. Gene expression studies and ingenuity pathway analysis identified a network of ERβ down-regulated genes involved in cell cycle progression including CDK1, cyclin B and cyclin H. siRNA mediated knockdown or drug inhibition of CDK1 and CDK7 in TNBC cells resulted in substantial decreases in proliferation regardless of ERβ expression. These data suggest that the tumor suppressive effects of ERβ in TNBC result from inhibition of cell cycle progression, effects that are in part mediated by suppression of CDK1/7. Furthermore, these data indicate that blockade of CDK1/7 activity in TNBC may be of therapeutic benefit, an area of study that has yet to be explored.
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Affiliation(s)
- Jordan M Reese
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Elizabeth S Bruinsma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - David G Monroe
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Vivian Negron
- Department of Pathology, Mayo Clinic, Rochester, MN, USA
| | - Vera J Suman
- Department of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA
| | - James N Ingle
- Department of Oncology, Mayo Clinic, Rochester, MN, USA
| | - Matthew P Goetz
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Department of Oncology, Mayo Clinic, Rochester, MN, USA
| | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
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15
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Gingery A, Iwaniec UT, Subramaniam M, Turner RT, Pitel KS, McGovern RM, Reid JM, Marler RJ, Ingle JN, Goetz MP, Hawse JR. Skeletal and Uterotrophic Effects of Endoxifen in Female Rats. Endocrinology 2017; 158:3354-3368. [PMID: 28977607 PMCID: PMC5659691 DOI: 10.1210/en.2016-1871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 07/31/2017] [Indexed: 12/24/2022]
Abstract
Endoxifen, the primary active metabolite of tamoxifen, is currently being investigated as a novel endocrine therapy for the treatment of breast cancer. Tamoxifen is a selective estrogen receptor modulator that elicits potent anti-breast cancer effects. However, long-term use of tamoxifen also induces bone loss in premenopausal women and is associated with an increased risk of endometrial cancer in postmenopausal women. For these reasons, we have used a rat model system to comprehensively characterize the impact of endoxifen on the skeleton and uterus. Our results demonstrate that endoxifen elicits beneficial effects on bone in ovary-intact rats and protects against bone loss following ovariectomy. Endoxifen is also shown to reduce bone turnover in both ovary-intact and ovariectomized rats at the cellular and biochemical levels. With regard to the uterus, endoxifen decreased uterine weight but maintained luminal epithelial cell height in ovariectomized animals. Within luminal epithelial cells, endoxifen resulted in differential effects on the expression levels of estrogen receptors α and β as well as multiple other genes previously implicated in regulating epithelial cell proliferation and hypertrophy. These studies analyze the impact of extended endoxifen exposure on both bone and uterus using a Food and Drug Administration-recommended animal model. Although endoxifen is a more potent breast cancer agent than tamoxifen, the results of the present study demonstrate that endoxifen does not induce bone loss in ovary-intact rats and that it elicits partial agonistic effects on the uterus and skeleton in ovariectomized animals.
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Affiliation(s)
- Anne Gingery
- Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331
| | - Malayannan Subramaniam
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon 97331
| | - Kevin S. Pitel
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Renee M. McGovern
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905
| | - Joel M. Reid
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota 55905
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905
| | - Ronald J. Marler
- Department of Comparative Medicine, Mayo Clinic, Scottsdale, Arizona 85259
| | - James N. Ingle
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905
| | | | - John R. Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
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16
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Tapia-Moreno A, Juarez-Moreno K, Gonzalez-Davis O, Cadena-Nava RD, Vazquez-Duhalt R. Biocatalytic virus capsid as nanovehicle for enzymatic activation of Tamoxifen in tumor cells. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201600706] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/28/2017] [Accepted: 03/31/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Alejandro Tapia-Moreno
- Centro de Nanociencias y Nanotecnología; Universidad Nacional Autónoma de México; Ensenada Baja California Mexico
| | - Karla Juarez-Moreno
- Centro de Nanociencias y Nanotecnología; Universidad Nacional Autónoma de México; Ensenada Baja California Mexico
| | - Oscar Gonzalez-Davis
- Centro de Nanociencias y Nanotecnología; Universidad Nacional Autónoma de México; Ensenada Baja California Mexico
| | - Ruben D. Cadena-Nava
- Centro de Nanociencias y Nanotecnología; Universidad Nacional Autónoma de México; Ensenada Baja California Mexico
| | - Rafael Vazquez-Duhalt
- Centro de Nanociencias y Nanotecnología; Universidad Nacional Autónoma de México; Ensenada Baja California Mexico
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17
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Paramita P, Louisa M, Nafrialdi N. Increased vimentin mRNA expression in MCF-7 breast cancer cell line after repeated endoxifen-treatment. MEDICAL JOURNAL OF INDONESIA 2017. [DOI: 10.13181/mji.v25i4.1397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Background: Epithelial mesenchymal transition (EMT) plays a significant role in the development of cancer cell resistance to drugs. Vimentin, a type III intermediate filament protein, is a marker of EMT. Vimentin's over-expression in cancer correlates well with increased tumor growth, change in cell shape and poor prognosis. Endoxifen is an active metabolite of tamoxifen and has become a new potent agent in the treatment of breast cancer. This is a study that aimed to investigate the effect of endoxifen exposure with or without estradiol on cell viability, cell morphology and EMT progression through the analysis of vimentin mRNA expression after 4-week treatment.
Methods: Endoxifen, 100 nM or 1,000 nM, with or without beta-estradiol were given repeatedly to MCF-7 cells. Cells treated with dimethyl sulfoxide (DMSO) 0.001% were used as control. After 2- and 4-week exposure, the cells were counted, analyzed for mRNA vimentin expression, and observed for morphological changes.
Results: Compared to control, there were significant decreases in vimentin mRNA expressions in endoxifen and endoxifen+β-estradiol treated cells after 2-weeks, which then significantly increased after 4-week compared with the 2-week exposure. We found no change in morphology of MCF-7 cells.
Conclusion: Repeated exposure of endoxifen might induce EMT progression through increased expression of vimentin in MCF-7 breast cancer cell line.
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18
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Tamoxifen metabolite endoxifen interferes with the polyamine pathway in breast cancer. Amino Acids 2016; 48:2293-302. [PMID: 27438264 DOI: 10.1007/s00726-016-2300-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 07/11/2016] [Indexed: 12/27/2022]
Abstract
Tamoxifen is the most widely used drug to treat women with estrogen receptor α (ERα)-positive breast cancer. Endoxifen is recognized as the active metabolite of tamoxifen in humans. We studied endoxifen effects on ERα-positive MCF-7 breast cancer cells. Estradiol increased the proliferation of MCF-7 cells by two- to threefold and endoxifen suppressed its effects. Endoxifen suppressed c-myc, c-fos and Tff1 oncogene expression, as revealed by RT-PCR. Estradiol increased the activity of ornithine decarboxylase (ODC) and adenosyl methioninedecarboxylase (AdoMetDC), whereas endoxifen suppressed these enzyme activities. Endoxifen increased activities of spermine oxidase (SMO) and acetyl polyamine oxidase (APAO) significantly, and reduced the levels of putrescine and spermidine. These data suggest a possible mechanism for the antiestrogenic effects of tamoxifen/endoxifen, involving the stimulation of polyamine oxidase enzymes. Therefore, SMO and APAO stimulation might be useful biomarkers for the efficacy of endoxifen treatment of breast cancer.
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19
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Fox P, Balleine RL, Lee C, Gao B, Balakrishnar B, Menzies AM, Yeap SH, Ali SS, Gebski V, Provan P, Coulter S, Liddle C, Hui R, Kefford R, Lynch J, Wong M, Wilcken N, Gurney H. Dose Escalation of Tamoxifen in Patients with Low Endoxifen Level: Evidence for Therapeutic Drug Monitoring-The TADE Study. Clin Cancer Res 2016; 22:3164-71. [PMID: 26847054 DOI: 10.1158/1078-0432.ccr-15-1470] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/17/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Endoxifen is the major mediator of tamoxifen effect and endoxifen levels <15 nmol/L may be associated with increased risk of breast cancer recurrence. We increased tamoxifen dose in breast cancer patients with low endoxifen levels and assessed the influence of various parameters on reaching 15 nmol/L and 30 nmol/L endoxifen levels. EXPERIMENTAL DESIGN Tamoxifen dose was increased in those with endoxifen levels below 30 nmol/L. Toxicity, including hot flash score, was measured. CYP2D6 metabolizer status was classified as ultra-rapid (UM), extensive (EM), intermediate (IM), or poor (PM) based genotype of somatic DNA. RESULTS Dosage was escalated in 68 of 122 participants. On 20 mg tamoxifen, 24% had endoxifen levels below 15 nmol/L and this reduced to 6% following dose escalation. In over 50% of cases, there was no identified cause for low endoxifen. Low baseline endoxifen level, and not CYP2D6 metabolizer status, independently predicted reaching threshold targets for both the 15 nmol/L and 30 nmol/L targets (P = 0.04 and 0.003 respectively). The 15 nmol/L target was reached in all UM/EM and IM patients, 63% of PM patients, and 58% of those with baseline endoxifen of <10 nmol/L. There was no correlation between hot flash score and genotype or any tamoxifen metabolite level including endoxifen (R = 0.07). CONCLUSIONS Low endoxifen on standard dose tamoxifen was the only independent predictor of failure to achieve potentially therapeutic levels. Trials examining tamoxifen dose escalation and breast cancer outcome should be guided by endoxifen levels alone, without reference to CYP2D6 genotype or presence of hot flashes. Clin Cancer Res; 22(13); 3164-71. ©2016 AACRSee related commentary by Hertz and Rae, p. 3121.
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Affiliation(s)
- Peter Fox
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Rosemary L Balleine
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Pathology West, Institute for Clinical Pathology and Medical Research, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Westmead Millennium Institute for Medical Research, Westmead, Australia
| | - Clara Lee
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Bo Gao
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | | | | | - Shang Heng Yeap
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | | | - Val Gebski
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Pamela Provan
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Sally Coulter
- Westmead Millennium Institute for Medical Research, Westmead, Australia
| | - Christopher Liddle
- Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Westmead Millennium Institute for Medical Research, Westmead, Australia. Storr Liver Centre, Westmead Hospital, Westmead, Australia
| | - Rina Hui
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Richard Kefford
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | | | - Mark Wong
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Nicholas Wilcken
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Howard Gurney
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Faculty of Medicine and Health Sciences, Macquarie University, Sydney Australia.
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20
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Safgren SL, Suman VJ, Kosel ML, Gilbert JA, Buhrow SA, Black JL, Northfelt DW, Modak AS, Rosen D, Ingle JN, Ames MM, Reid JM, Goetz MP. Evaluation of CYP2D6 enzyme activity using a 13C-dextromethorphan breath test in women receiving adjuvant tamoxifen. Pharmacogenet Genomics 2015; 25:157-63. [PMID: 25714002 DOI: 10.1097/fpc.0000000000000121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND In tamoxifen-treated patients, breast cancer recurrence differs according to CYP2D6 genotype and endoxifen steady-state concentrations (Endx Css). The ¹³C-dextromethorphan breath test (DM-BT), labeled with ¹³C at the O-CH3 moiety, measures CYP2D6 enzyme activity. We sought to examine the ability of the DM-BT to identify known CYP2D6 genotypic poor metabolizers and examine the correlation between DM-BT and Endx Css. METHODS DM-BT and tamoxifen pharmacokinetics were obtained at baseline, 3, and 6 months following tamoxifen initiation. Potent CYP2D6 inhibitors were prohibited. The correlation between baseline DM-BT with CYP2D6 genotype and Endx Css was determined. The association between baseline DM-BT (where values ≤0.9 is an indicator of poor in vivo CYP2D6 metabolism) and Endx Css (using values≤11.2 known to be associated with poorer recurrence free survival) was explored. RESULTS A total of 91 patients were enrolled and 77 were eligible. CYP2D6 genotype was positively correlated with baseline, 3, and 6 months DM-BT (r ranging from 0.457-0. 60; P<0.001). Both CYP2D6 genotype (r=0.47, 0.56, P<0.0001), and baseline DM-BT (r=0.60, 0.54, P<0.001) were associated with 3 and 6 months Endx Css, respectively. Seven (78%) of nine patients with low (≤11.2 nmol/l) 3 month Endx Css also had low DM-BT (≤0.9) including 2/2 CYP2D6 PM/PM and 5/5 IM/PM. In contrast, one (2%) of 48 patients with a low DM-BT had Endx Css more than 11.2 nmol/l. CONCLUSION In patients not taking potent CYP2D6 inhibitors, DM-BT was associated with CYP2D6 genotype and 3 and 6 months Endx Css but did not provide better discrimination of Endx Css compared with CYP2D6 genotype alone. Further studies are needed to identify additional factors which alter Endx Css.
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Affiliation(s)
- Stephanie L Safgren
- Departments of aOncology bMolecular Pharmacology and Experimental Therapeutics cBiostatistics dLaboratory Medicine, Mayo Clinic, Rochester, Minnesota eDepartment of Hematology and Oncology, Mayo Clinic, Scottsdale, Arizona fCambridge Isotope Laboratories Inc. gPhysical Sciences Inc., Andover, Massachusetts, USA
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Activity of the antiestrogenic cajanin stilbene acid towards breast cancer. J Nutr Biochem 2015; 26:1273-82. [DOI: 10.1016/j.jnutbio.2015.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 06/03/2015] [Accepted: 06/10/2015] [Indexed: 02/07/2023]
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Hennig EE, Piatkowska M, Karczmarski J, Goryca K, Brewczynska E, Jazwiec R, Kluska A, Omiotek R, Paziewska A, Dadlez M, Ostrowski J. Limited predictive value of achieving beneficial plasma (Z)-endoxifen threshold level by CYP2D6 genotyping in tamoxifen-treated Polish women with breast cancer. BMC Cancer 2015; 15:570. [PMID: 26232141 PMCID: PMC4522133 DOI: 10.1186/s12885-015-1575-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/27/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Tamoxifen, the most frequently used drug for treating estrogen receptor-positive breast cancer, must be converted into active metabolites to exert its therapeutic efficacy, mainly through CYP2D6 enzymes. The objective of this study was to investigate the impact of CYP2D6 polymorphisms on (Z)-endoxifen-directed tamoxifen metabolism and to assess the usefulness of CYP2D6 genotyping for identifying patients who are likely to have insufficient (Z)-endoxifen concentrations to benefit from standard therapy. METHODS Blood samples from 279 Polish women with breast cancer receiving tamoxifen 20 mg daily were analyzed for CYP2D6 genotype and drug metabolite concentration. Steady-state plasma levels of tamoxifen and its 14 metabolites were measured by using the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. RESULTS In nearly 60 % of patients, including over 30 % of patients with fully functional CYP2D6, (Z)-endoxifen concentration was below the predefined threshold of therapeutic efficacy. The most frequently observed CYP2D6 genotype was EM/PM (34.8 %), among which 83.5 % of patients had a combination of wild-type and *4 alleles. Plasma concentration of five metabolites was significantly correlated with CYP2D6 genotype. For the first time, we identified an association between decreased (E/Z)-4-OH-N-desmethyl-tamoxifen-β-D-glucuronide levels (r (2) = 0.23; p < 10(-16)) and increased CYP2D6 functional impairment. The strongest correlation was observed for (Z)-endoxifen, whose concentration was significantly lower in groups of patients carrying at least one CYP2D6 null allele, compared with EM/EM patients. The CYP2D6 genotype accounted for plasma level variability of (Z)-endoxifen by 27 % (p < 10(-16)) and for the variability of metabolic ratio indicating (Z)-endoxifen-directed metabolism of tamoxifen by 51 % (p < 10(-43)). CONCLUSIONS The majority of breast cancer patients in Poland may not achieve a therapeutic level of (Z)-endoxifen upon receiving a standard dose of tamoxifen. This finding emphasizes the limited value of CYP2D6 genotyping in routine clinical practice for identifying patients who might not benefit from the therapy. In its place, direct monitoring of plasma steady-state (Z)-endoxifen concentration should be performed to personalize and optimize the treatment.
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Affiliation(s)
- Ewa E Hennig
- Department of Gastroenterology, Hepatology and Clinical Oncology, Medical Center for Postgraduate Education, Warsaw, Poland. .,Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland. .,Cancer Center-Institute, Roentgena 5, 02-781, Warsaw, Poland.
| | - Magdalena Piatkowska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Jakub Karczmarski
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Krzysztof Goryca
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Elzbieta Brewczynska
- Department of Breast Cancer and Reconstructive Surgery, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Radoslaw Jazwiec
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
| | - Anna Kluska
- Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Robert Omiotek
- Department of Internal Medicine and Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
| | - Agnieszka Paziewska
- Department of Gastroenterology, Hepatology and Clinical Oncology, Medical Center for Postgraduate Education, Warsaw, Poland.
| | - Michal Dadlez
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
| | - Jerzy Ostrowski
- Department of Gastroenterology, Hepatology and Clinical Oncology, Medical Center for Postgraduate Education, Warsaw, Poland. .,Department of Genetics, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland.
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Maximov PY, McDaniel RE, Fernandes DJ, Korostyshevskiy VR, Bhatta P, Mürdter TE, Flockhart DA, Jordan VC. Simulation with cells in vitro of tamoxifen treatment in premenopausal breast cancer patients with different CYP2D6 genotypes. Br J Pharmacol 2015; 171:5624-35. [PMID: 25073551 DOI: 10.1111/bph.12864] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/25/2014] [Accepted: 07/22/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Tamoxifen is a prodrug that is metabolically activated by 4-hydroxylation to the potent primary metabolite 4-hydroxytamoxifen (4OHT) or via another primary metabolite N-desmethyltamoxifen (NDMTAM) to a biologically active secondary metabolite endoxifen through a cytochrome P450 2D6 variant system (CYP2D6). To elucidate the mechanism of action of tamoxifen and the importance of endoxifen for its effect, we determined the anti-oestrogenic efficacy of tamoxifen and its metabolites, including endoxifen, at concentrations corresponding to serum levels measured in breast cancer patients with various CYP2D6 genotypes (simulating tamoxifen treatment). EXPERIMENTAL APPROACH The biological effects of tamoxifen and its metabolites on cell growth and oestrogen-responsive gene modulation were evaluated in a panel of oestrogen receptor-positive breast cancer cell lines. Actual clinical levels of tamoxifen metabolites in breast cancer patients were used in vitro along with actual levels of oestrogens observed in premenopausal patients taking tamoxifen. KEY RESULTS Tamoxifen and its primary metabolites (4OHT and NDMTAM) only partially inhibited the stimulant effects of oestrogen on cells. The addition of endoxifen at concentrations corresponding to different CYP2D6 genotypes was found to enhance the anti-oestrogenic effect of tamoxifen and its metabolites with an efficacy that correlated with the concentration of endoxifen; at concentrations corresponding to the extensive metabolizer genotype it further inhibited the actions of oestrogen. In contrast, lower concentrations of endoxifen (intermediate and poor metabolizers) had little or no anti-oestrogenic effects. CONCLUSIONS AND IMPLICATIONS Endoxifen may be a clinically relevant metabolite in premenopausal patients as it provides additional anti-oestrogenic actions during tamoxifen treatment.
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Affiliation(s)
- Philipp Y Maximov
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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Jager NGL, Linn SC, Schellens JHM, Beijnen JH. Tailored Tamoxifen Treatment for Breast Cancer Patients: A Perspective. Clin Breast Cancer 2015; 15:241-4. [PMID: 25997856 DOI: 10.1016/j.clbc.2015.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/01/2015] [Accepted: 04/16/2015] [Indexed: 11/20/2022]
Abstract
Tamoxifen, an endocrine agent, is widely used in the treatment of estrogen receptor-positive breast cancer. It has greatly reduced disease recurrence and mortality rates of breast cancer patients, however, not all patients benefit from tamoxifen treatment because in approximately 25% to 30% of the patients the disease recurs. Many researchers have sought to find factors associated with endocrine treatment outcome in the past years, however, this quest has not been finished. In this article, we focus on a factor that might influence outcome of tamoxifen treatment: interpatient variability in tamoxifen pharmacokinetics. In recent years it has become clear that tamoxifen undergoes extensive metabolism and that some of the formed metabolites are much more pharmacologically active than tamoxifen itself. Despite the wide interpatient variability in tamoxifen pharmacokinetics and pharmacodynamics, all patients receive a standard dose of 20 mg tamoxifen per day. Different approaches can be pursued to individualize tamoxifen dosing: genotyping, phenotyping, and therapeutic drug monitoring. Therapeutic drug monitoring seems to be the most direct and promising approach, however, further clinical research is warranted to establish the added value of individual dosing in tamoxifen treatment optimization.
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Affiliation(s)
- Nynke G L Jager
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute/Slotervaart Hospital, Amsterdam, The Netherlands.
| | - Sabine C Linn
- Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jan H M Schellens
- Department of Clinical Pharmacology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Faculty of Science, Utrecht Institute of Pharmaceutical Sciences (UIPS), Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands
| | - Jos H Beijnen
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute/Slotervaart Hospital, Amsterdam, The Netherlands; Department of Clinical Pharmacology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Faculty of Science, Utrecht Institute of Pharmaceutical Sciences (UIPS), Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands
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Helland T, Gjerde J, Dankel S, Fenne IS, Skartveit L, Drangevåg A, Bozickovic O, Flågeng MH, Søiland H, Mellgren G, Lien EA. The active tamoxifen metabolite endoxifen (4OHNDtam) strongly down-regulates cytokeratin 6 (CK6) in MCF-7 breast cancer cells. PLoS One 2015; 10:e0122339. [PMID: 25867603 PMCID: PMC4395096 DOI: 10.1371/journal.pone.0122339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 02/11/2015] [Indexed: 11/19/2022] Open
Abstract
Introduction Tamoxifen is an anti-estrogen drug used in treatment of Estrogen Receptor (ER) positive breast cancer. Effects and side effects of tamoxifen is the sum of tamoxifen and all its metabolites. 4-Hydroxytamoxifen (4OHtam) and 4-hydroxy-N-demethyltamoxifen (4OHNDtam, endoxifen) both have ER affinity exceeding that of the parent drug tamoxifen. 4OHNDtam is considered the main active metabolite of tamoxifen. Ndesmethyltamoxifen (NDtam) is the major tamoxifen metabolite. It has low affinity to the ER and is not believed to influence tumor growth. However, NDtam might mediate adverse effects of tamoxifen treatment. In this study we investigated the gene regulatory effects of the three metabolites of tamoxifen in MCF-7 breast cancer cells. Material and Methods Using concentrations that mimic the clinical situation we examined effects of 4OHtam, 4OHNDtam and NDtam on global gene expression in 17β-estradiol (E2) treated MCF-7 cells. Transcriptomic responses were assessed by correspondence analysis, differential expression, gene ontology analysis and quantitative real time PCR (Q-rt-PCR). E2 deprivation and knockdown of Steroid Receptor Coactivator-3 (SRC-3)/Amplified in Breast Cancer 1 (AIB1) mRNA in MCF-7 cells were performed to further characterize specific effects on gene expression. Results 4OHNDtam and 4OHtam caused major changes in gene expression compared to treatment with E2 alone, with a stronger effect of 4OHNDtam. NDtam had nearly no effect on the global gene expression profile. Treatment of MCF-7 cells with 4OHNDtam led to a strong down-regulation of the CytoKeratin 6 isoforms (KRT6A, KRT6B and KRT6C). The CytoKeratin 6 mRNAs were also down-regulated in MCF-7 cells after E2 deprivation and after SRC-3/AIB1 knockdown. Conclusion Using concentrations that mimic the clinical situation we report global gene expression changes that were most pronounced with 4OHNDtam and minimal with NDtam. Genes encoding CytoKeratin 6, were highly down-regulated by 4OHNDtam, as well as after E2 deprivation and knockdown of SRC-3/AIB1, indicating an estrogen receptor-dependent regulation.
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Affiliation(s)
- Thomas Helland
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Jennifer Gjerde
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Simon Dankel
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ingvild S. Fenne
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Linn Skartveit
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Andreas Drangevåg
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Olivera Bozickovic
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Marianne Hauglid Flågeng
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Håvard Søiland
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Section for Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Gunnar Mellgren
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ernst A. Lien
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
- * E-mail:
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Binkhorst L, Mathijssen RH, Jager A, van Gelder T. Individualization of tamoxifen therapy: Much more than just CYP2D6 genotyping. Cancer Treat Rev 2015; 41:289-99. [DOI: 10.1016/j.ctrv.2015.01.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 12/30/2014] [Accepted: 01/07/2015] [Indexed: 12/12/2022]
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Determination of tamoxifen and endoxifen in dried blood spots using LC–MS/MS and the effect of coated DBS cards on recovery and matrix effects. Bioanalysis 2014; 6:2999-3009. [DOI: 10.4155/bio.14.157] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: We developed an HPLC-MS/MS method to quantify tamoxifen (2.5–250 ng/ml) and its metabolite (Z)-endoxifen (0.5–50 ng/ml) in dried blood spots. Results: Extraction recovery of both analytes from Whatman DMPK-A cards was 100% and consistent over time, however, recovery of (Z)-endoxifen from Whatman 903 cards was incomplete and increased upon storage. When SDS, a constituent of the DMPK-A coating, was present during the extraction, recovery improved. The method using DMPK-A cards was validated using bioanalytical guidelines. Additionally, influence of haematocrit (0.29–0.48 L/L), spot volume (20–50µl) and homogeneity was within limits and both analytes were stable in DBS for at least 4 months. Conclusions: The method for the quantification of tamoxifen and (Z)-endoxifen in DBS collected on DMPK-A cards was successfully validated.
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Reese JM, Suman VJ, Subramaniam M, Wu X, Negron V, Gingery A, Pitel KS, Shah SS, Cunliffe HE, McCullough AE, Pockaj BA, Couch FJ, Olson JE, Reynolds C, Lingle WL, Spelsberg TC, Goetz MP, Ingle JN, Hawse JR. ERβ1: characterization, prognosis, and evaluation of treatment strategies in ERα-positive and -negative breast cancer. BMC Cancer 2014; 14:749. [PMID: 25288324 PMCID: PMC4196114 DOI: 10.1186/1471-2407-14-749] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/25/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The role and clinical value of ERβ1 expression is controversial and recent data demonstrates that many ERβ antibodies are insensitive and/or non-specific. Therefore, we sought to comprehensively characterize ERβ1 expression across all sub-types of breast cancer using a validated antibody and determine the roles of this receptor in mediating response to multiple forms of endocrine therapy both in the presence and absence of ERα expression. METHODS Nuclear and cytoplasmic expression patterns of ERβ1 were analyzed in three patient cohorts, including a retrospective analysis of a prospective adjuvant tamoxifen study and a triple negative breast cancer cohort. To investigate the utility of therapeutically targeting ERβ1, we generated multiple ERβ1 expressing cell model systems and determined their proliferative responses following anti-estrogenic or ERβ-specific agonist exposure. RESULTS Nuclear ERβ1 was shown to be expressed across all major sub-types of breast cancer, including 25% of triple negative breast cancers and 33% of ER-positive tumors, and was associated with significantly improved outcomes in ERα-positive tamoxifen-treated patients. In agreement with these observations, ERβ1 expression sensitized ERα-positive breast cancer cells to the anti-cancer effects of selective estrogen receptor modulators (SERMs). However, in the absence of ERα expression, ERβ-specific agonists potently inhibited cell proliferation rates while anti-estrogenic therapies were ineffective. CONCLUSIONS Using a validated antibody, we have confirmed that nuclear ERβ1 expression is commonly present in breast cancer and is prognostic in tamoxifen-treated patients. Using multiple breast cancer cell lines, ERβ appears to be a novel therapeutic target. However, the efficacy of SERMs and ERβ-specific agonists differ as a function of ERα expression.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, 16-01B Guggenheim Building, 200 First St, SW, Rochester, MN 55905, USA.
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Maximov PY, McDaniel RE, Fernandes DJ, Bhatta P, Korostyshevskiy VR, Curpan RF, Jordan VC. Pharmacological relevance of endoxifen in a laboratory simulation of breast cancer in postmenopausal patients. J Natl Cancer Inst 2014; 106:dju283. [PMID: 25258390 DOI: 10.1093/jnci/dju283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Tamoxifen is metabolically activated via a CYP2D6 enzyme system to the more potent hydroxylated derivatives 4-hydroxytamoxifen and endoxifen. This study addresses the pharmacological importance of endoxifen by simulating clinical scenarios in vitro. METHODS Clinical levels of tamoxifen metabolites in postmenopausal breast cancer patients previously genotyped for CYP2D6 were used in vitro along with clinical estrogen levels (estrone and estradiol) in postmenopausal patients determined in previous studies. The biological effects on cell growth were evaluated in a panel of estrogen receptor-positive breast cancer cell lines via cell proliferation assays and real-time polymerase chain reaction (PCR). Data were analyzed with one- and two-way analysis of variance and Student's t test. All statistical tests were two-sided. RESULTS Postmenopausal levels of estrogen-induced proliferation of all test breast cancer cell lines (mean fold induction ± SD vs vehicle control: MCF-7 = 11 ± 1.74, P < .001; T47D = 7.52 ± 0.72, P < .001; BT474 = 1.75 ± 0.23, P < .001; ZR-75-1 = 5.5 ± 1.95, P = .001. Tamoxifen and primary metabolites completely inhibited cell growth regardless of the CYP2D6 genotype in all cell lines (mean fold induction ± SD vs vehicle control: MCF-7 = 1.57 ± 0.38, P = .54; T47D = 1.17 ± 0.23, P = .79; BT474 = 0.96 ± 0.2, P = .98; ZR-75-1 = 0.86 ± 0.67, P = .99). Interestingly, tamoxifen and its primary metabolites were not able to fully inhibit the estrogen-stimulated expression of estrogen-responsive genes in MCF-7 cells (P < .05 for all genes), but the addition of endoxifen was able to produce additional antiestrogenic effect on these genes. CONCLUSIONS The results indicate that tamoxifen and other metabolites, excluding endoxifen, completely inhibit estrogen-stimulated growth in all cell lines, but additional antiestrogenic action from endoxifen is necessary for complete blockade of estrogen-stimulated genes. Endoxifen is of supportive importance for the therapeutic effect of tamoxifen in a postmenopausal setting.
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Affiliation(s)
- Philipp Y Maximov
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - Russell E McDaniel
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - Daphne J Fernandes
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - Puspanjali Bhatta
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - Valeriy R Korostyshevskiy
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - Ramona F Curpan
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC)
| | - V Craig Jordan
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (PYM, REM, DJF, PB, VRK, CJ); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RFC).
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Use of dried blood spots for the determination of serum concentrations of tamoxifen and endoxifen. Breast Cancer Res Treat 2014; 146:137-44. [DOI: 10.1007/s10549-014-2999-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 05/10/2014] [Indexed: 11/25/2022]
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Gingery A, Subramaniam M, Pitel KS, Reese JM, Cicek M, Lindenmaier LB, Ingle JN, Goetz MP, Turner RT, Iwaniec UT, Spelsberg TC, Hawse JR. The effects of a novel hormonal breast cancer therapy, endoxifen, on the mouse skeleton. PLoS One 2014; 9:e98219. [PMID: 24853369 PMCID: PMC4031133 DOI: 10.1371/journal.pone.0098219] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/30/2014] [Indexed: 11/19/2022] Open
Abstract
Endoxifen has recently been identified as the predominant active metabolite of tamoxifen and is currently being developed as a novel hormonal therapy for the treatment of endocrine sensitive breast cancer. Based on past studies in breast cancer cells and model systems, endoxifen classically functions as an anti-estrogenic compound. Since estrogen and estrogen receptors play critical roles in mediating bone homeostasis, and endoxifen is currently being implemented as a novel breast cancer therapy, we sought to comprehensively characterize the in vivo effects of endoxifen on the mouse skeleton. Two month old ovariectomized C57BL/6 mice were treated with vehicle or 50 mg/kg/day endoxifen hydrochloride via oral gavage for 45 days. Animals were analyzed by dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, micro-computed tomography and histomorphometry. Serum from control and endoxifen treated mice was evaluated for bone resorption and bone formation markers. Gene expression changes were monitored in osteoblasts, osteoclasts and the cortical shells of long bones from endoxifen treated mice and in a human fetal osteoblast cell line. Endoxifen treatment led to significantly higher bone mineral density and bone mineral content throughout the skeleton relative to control animals. Endoxifen treatment also resulted in increased numbers of osteoblasts and osteoclasts per tissue area, which was corroborated by increased serum levels of bone formation and resorption markers. Finally, endoxifen induced the expression of osteoblast, osteoclast and osteocyte marker genes. These studies are the first to examine the in vivo and in vitro impacts of endoxifen on bone and our results demonstrate that endoxifen increases cancellous as well as cortical bone mass in ovariectomized mice, effects that may have implications for postmenopausal breast cancer patients.
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Affiliation(s)
- Anne Gingery
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Malayannan Subramaniam
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Kevin S. Pitel
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jordan M. Reese
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Muzaffer Cicek
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Laurence B. Lindenmaier
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - James N. Ingle
- Department of Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Matthew P. Goetz
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Oncology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Russell T. Turner
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - Urszula T. Iwaniec
- Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - Thomas C. Spelsberg
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - John R. Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
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33
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Schweikart KM, Eldridge SR, Safgren SL, Parman T, Reid JM, Ames MM, Goetz MP, Davis MA. Comparative uterotrophic effects of endoxifen and tamoxifen in ovariectomized Sprague-Dawley rats. Toxicol Pathol 2014; 42:1188-96. [PMID: 24670817 DOI: 10.1177/0192623314525688] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Endoxifen (4-hydroxy-N-desmethyl-tamoxifen), one of the major active metabolites of tamoxifen, has substantially greater estrogen antagonist properties and antiproliferative effects in breast tumor cells than tamoxifen, a mixed estrogen agonist/antagonist. An associated risk of endometrial cancer and hyperplasia has been linked to the estrogen agonist properties of tamoxifen. We evaluated endoxifen using a classic uterotrophic effects method. Rats were given endoxifen or tamoxifen orally for 3 days. Estradiol was the positive control. Endoxifen and tamoxifen plasma levels exceeded those previously observed clinically. Uterine weight was 3-fold higher in the estradiol group than in the tamoxifen or endoxifen groups, which did not differ from vehicle controls. Tamoxifen and endoxifen caused a greater increase in luminal epithelial cell height than estradiol. Both tamoxifen and endoxifen produced an increase in the stromal BrdU labeling index (LI) that was ≤ estradiol and inversely related to dose, but did not affect luminal epithelial cell BrdU LI. As expected, estradiol increased luminal epithelial cell proliferation. These results indicate that endoxifen induces uterotrophic effects, but is less potent than estradiol in eliciting these effects. Given prior preclinical observations that endoxifen has superior antitumor activity than tamoxifen, the observations of similar uterine effects suggest that the endoxifen risk/benefit ratio may be superior to tamoxifen.
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Affiliation(s)
- Karen M Schweikart
- Developmental Therapeutics Program, National Cancer Institute, Bethesda, Maryland, USA
| | - Sandy R Eldridge
- Charles River Laboratories Pathology Associates, Frederick, Maryland, USA Present address: Developmental Therapeutics Program, National Cancer Institute, Bethesda, MD, USA
| | | | | | | | | | | | - Myrtle A Davis
- Developmental Therapeutics Program, National Cancer Institute, Bethesda, Maryland, USA
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Stokes G, Conboy JC. Measuring selective estrogen receptor modulator (SERM)-membrane interactions with second harmonic generation. J Am Chem Soc 2014; 136:1409-17. [PMID: 24410282 PMCID: PMC4004268 DOI: 10.1021/ja409250y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Indexed: 12/29/2022]
Abstract
The interaction of selective estrogen receptor modulators (SERMs) with lipid membranes has been measured at clinically relevant serum concentrations using the label-free technique of second harmonic generation (SHG). The SERMs investigated in this study include raloxifene, tamoxifen, and the tamoxifen metabolites 4-hydroxytamoxifen, N-desmethyltamoxifen, and endoxifen. Equilibrium association constants (Ka) were measured for SERMs using varying lipid compositions to examine how lipid phase, packing density, and cholesterol content impact SERM-membrane interactions. Membrane-binding properties of tamoxifen and its metabolites were compared on the basis of hydroxyl group substitution and amine ionization to elucidate how the degree of drug ionization impacts membrane partitioning. SERM-membrane interactions were probed under multiple pH conditions, and drug adsorption was observed to vary with the concentration of soluble neutral species. The agreement between Ka values derived from SHG measurements of the interactions between SERMs and artificial cell membranes and independent observations of the SERMs efficacy from clinical studies suggests that quantifying membrane adsorption properties may be important for understanding SERM action in vivo.
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Affiliation(s)
- Grace
Y. Stokes
- Department
of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake
City, Utah 84112, United States
| | - John C. Conboy
- Department
of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake
City, Utah 84112, United States
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35
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Jager NGL, Rosing H, Schellens JHM, Linn SC, Beijnen JH. Tamoxifen dose and serum concentrations of tamoxifen and six of its metabolites in routine clinical outpatient care. Breast Cancer Res Treat 2014; 143:477-83. [PMID: 24390246 DOI: 10.1007/s10549-013-2826-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 12/23/2013] [Indexed: 12/01/2022]
Abstract
A sensitive and selective HPLC-MS/MS assay was used to analyze steady-state serum concentrations of tamoxifen, N-desmethyltamoxifen (E)-endoxifen, (Z)-endoxifen, N-desmethyl-4'-hydroxytamoxifen, 4-hydroxytamoxifen, and 4'-hydroxytamoxifen to support therapeutic drug monitoring (TDM) in patients treated with tamoxifen according to standard of care. When the (Z)-endoxifen serum concentration was below the predefined therapeutic threshold concentration of 5.9 ng/mL, the clinician was advised to increase the tamoxifen dose and to collect another serum sample. Paired serum samples from patients at one dose level at different time points during the tamoxifen treatment were used to assess the intra-patient variability. A total of 251 serum samples were analyzed, obtained from 205 patients. Of these patients, 197 used 20 mg tamoxifen per day and 8 patients used 10 mg/day. There was wide variability in tamoxifen and metabolite concentrations within the dosing groups. The threshold concentration for (Z)-endoxifen was reached in one patient (12 %) in the 10 mg group, in 153 patients (78 %) in the 20 mg group, and in 26 (96 %) of the patients who received a dose increase to 30 or 40 mg/day. Dose increase from 20 to 30 or 40 mg per day resulted in a significant increase in the mean serum concentrations of all analytes (p < 0.001). The mean intra-patient variability was between 10 and 20 % for all analytes. These results support the suitability of TDM for optimizing the tamoxifen treatment. It is shown that tamoxifen dose is related to (Z)-endoxifen exposure and increasing this dose leads to a higher serum concentration of tamoxifen and its metabolites. The low intra-patient variability suggests that only one serum sample is needed for TDM, making this a relatively noninvasive way to optimize the patient's treatment.
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Affiliation(s)
- N G L Jager
- Department of Pharmacy and Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute, Louwesweg 6, 1066 EC, Amsterdam, The Netherlands,
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