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Lim S, Choi S, Lee JK, Choi E, Lee S, Chun K, Baek M, Park J, Kim J, Kang A, Kim Y, Kim N, Cho B, Sim T, Lee K. Abstract 4006: TRX-221, a novel 4th-generation EGFR inhibitor for overcoming C797S mutation-mediated acquired resistance in NSCLC. Cancer Res 2023. [DOI: 10.1158/1538-7445.am2023-4006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Abstract
Targeting mutated EGFR is a clinically validated approach for tackling non-small cell lung cancer (NSCLC). Approximately 20% of patients with advanced NSCLC harbor an EGFR mutation. Osimertinib is a 3rd-generation oral EGFR-TKI targeting the EGFR sensitizing mutations Del19 and L858R, as well as an acquired mutation, T790M. Despite osimertinib's efficacy in NSCLC, resistance develops and the mechanisms of resistance to osimertinib are complex. Development of another mutation, C797S is the most common mechanism of acquired resistance following osimertinib treatment. This mutation occurs with about 12% frequency after a 1L therapy of osimertinib, and with approximately 17% frequency after a 2L therapy. Here, we report TRX-221 as a novel 4th-generation EGFR-TKI that can overcome C797S-mediated acquired resistance in NSCLC models in vitro and in vivo. TRX-221 exhibited potent inhibitory activity against multiple EGFR mutant kinases, including Del19/T790M/C797S, L858R/T790M/C797S, Del19/C797S, L858R/C797S, Del19/T790M, L858R/T790M, Del19, and L858R. Likewise, TRX-221 potently inhibited the proliferation of Ba/F3 cells stably overexpressing these eight EGFR mutants. TRX-221 however showed sparing activity against EGFR wild-type kinase and cell lines. TRX-221 also demonstrated marked anti-proliferative activity against osimertinib-resistant patient-derived cancer cell lines (PDCs). With favorable DMPK profiles, once-daily oral dosing of TRX-221 induced strong anti-tumor effects in a dose-dependent manner in a variety of osimertinib-resistant CDX and PDX models. As a reversible, selective, and broad-spectrum 4th-generation EGFR-TKI, TRX-221 is currently undergoing IND-enabling studies and shows strong potential as a therapeutic solution to treat advanced NSCLC patients harboring EGFR mutations.
Citation Format: Sumin Lim, Seulgi Choi, Ju-Kyung Lee, Eunhyun Choi, Sungwon Lee, Kwangwoo Chun, Myoungki Baek, Jiyeon Park, Jihyun Kim, Areum Kang, Younghoon Kim, Namkyoung Kim, Byoungchul Cho, Taebo Sim, Koo Lee. TRX-221, a novel 4th-generation EGFR inhibitor for overcoming C797S mutation-mediated acquired resistance in NSCLC. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4006.
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Affiliation(s)
- Sumin Lim
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | - Seulgi Choi
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | | | | | - Sungwon Lee
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | | | | | - Jiyeon Park
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | - Jihyun Kim
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | - Areum Kang
- 1Therapex Co., Ltd, Seoul, Republic of Korea
| | - Younghoon Kim
- 2Sevrance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Namkyoung Kim
- 2Sevrance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Byoungchul Cho
- 3Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Taebo Sim
- 2Sevrance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Koo Lee
- 1Therapex Co., Ltd, Seoul, Republic of Korea
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Wicky BIM, Milles LF, Courbet A, Ragotte RJ, Dauparas J, Kinfu E, Tipps S, Kibler RD, Baek M, DiMaio F, Li X, Carter L, Kang A, Nguyen H, Bera AK, Baker D. Hallucinating symmetric protein assemblies. Science 2022; 378:56-61. [PMID: 36108048 PMCID: PMC9724707 DOI: 10.1126/science.add1964] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Deep learning generative approaches provide an opportunity to broadly explore protein structure space beyond the sequences and structures of natural proteins. Here, we use deep network hallucination to generate a wide range of symmetric protein homo-oligomers given only a specification of the number of protomers and the protomer length. Crystal structures of seven designs are very similar to the computational models (median root mean square deviation: 0.6 angstroms), as are three cryo-electron microscopy structures of giant 10-nanometer rings with up to 1550 residues and C33 symmetry; all differ considerably from previously solved structures. Our results highlight the rich diversity of new protein structures that can be generated using deep learning and pave the way for the design of increasingly complex components for nanomachines and biomaterials.
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Affiliation(s)
- B. I. M. Wicky
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - L. F. Milles
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - A. Courbet
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - R. J. Ragotte
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - J. Dauparas
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - E. Kinfu
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - S. Tipps
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - R. D. Kibler
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - M. Baek
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - F. DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - X. Li
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - L. Carter
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - A. Kang
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - H. Nguyen
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - A. K. Bera
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - D. Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
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Siegel CA, Horton H, Siegel LS, Thompson KD, Mackenzie T, Stewart SK, Rice PW, Stempak JM, Dezfoli S, Haritunians T, Levy A, Baek M, Milgrom R, Dulai PS, Targan SR, Silverberg MS, Dubinsky MC, McGovern DP. A validated web-based tool to display individualised Crohn's disease predicted outcomes based on clinical, serologic and genetic variables. Aliment Pharmacol Ther 2016; 43:262-71. [PMID: 26567467 DOI: 10.1111/apt.13460] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 08/25/2015] [Accepted: 10/11/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND Early treatment for Crohn's disease (CD) with immunomodulators and/or anti-TNF agents improves outcomes in comparison to a slower 'step up' algorithm. However, there remains a limited ability to identify those who would benefit most from early intensive therapy. AIM To develop a validated, individualised, web-based tool for patients and clinicians to visualise individualised risks for developing Crohn's disease complications. METHODS A well-characterised cohort of adult patients with CD was analysed. Available data included: demographics; clinical characteristics; serologic immune responses; NOD2 status; time from diagnosis to complication; and medication exposure. Cox proportional analyses were performed to model the probability of developing a CD complication over time. The Cox model was validated externally in two independent CD cohorts. Using system dynamics analysis (SDA), these results were transformed into a simple graphical web-based display to show patients their individualised probability of developing a complication over a 3-year period. RESULTS Two hundered and forty three CD patients were included in the final model of which 142 experienced a complication. Significant variables in the multivariate Cox model included small bowel disease (HR 2.12, CI 1.05-4.29), left colonic disease (HR 0.73, CI 0.49-1.09), perianal disease (HR 4.12, CI 1.01-16.88), ASCA (HR 1.35, CI 1.16-1.58), Cbir (HR 1.29, CI 1.07-1.55), ANCA (HR 0.77, CI 0.62-0.95), and the NOD2 frameshift mutation/SNP13 (HR 2.13, CI 1.33-3.40). The Harrell's C (concordance index for predictive accuracy of the model) = 0.73. When applied to the two external validation cohorts (adult n = 109, pediatric n = 392), the concordance index was 0.73 and 0.75, respectively, for adult and pediatric patients. CONCLUSIONS A validated, web-based tool has been developed to display an individualised predicted outcome for adult patients with Crohn's disease based on clinical, serologic and genetic variables. This tool can be used to help providers and patients make personalised decisions about treatment options.
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Affiliation(s)
- C A Siegel
- Dartmouth-Hitchcock Inflammatory Bowel Disease Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.,Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - H Horton
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - L S Siegel
- Siegel Environmental Dynamics, Hanover, NH, USA.,Climate Interactive, Washington, DC, USA
| | - K D Thompson
- Dartmouth-Hitchcock Inflammatory Bowel Disease Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.,Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - T Mackenzie
- Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - S K Stewart
- Dartmouth-Hitchcock Inflammatory Bowel Disease Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - P W Rice
- Climate Interactive, Washington, DC, USA
| | - J M Stempak
- Zane Cohen Centre for Digestive Diseases, Division of Gastroenterology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - S Dezfoli
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - T Haritunians
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - A Levy
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - M Baek
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - R Milgrom
- Zane Cohen Centre for Digestive Diseases, Division of Gastroenterology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - P S Dulai
- Dartmouth-Hitchcock Inflammatory Bowel Disease Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.,Department of Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - S R Targan
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - M S Silverberg
- Zane Cohen Centre for Digestive Diseases, Division of Gastroenterology, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - M C Dubinsky
- Icahn School of Medicine at Mt. Sinai, New York, NY, USA
| | - D P McGovern
- F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Baek M, Ahn T, Shin E, Park D, Lee S, Kim I, Kim C, Choi W. 270. AEG-1 is associated with invasion and poor prognosis in colorectal cancer. Eur J Surg Oncol 2014. [DOI: 10.1016/j.ejso.2014.08.262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Lee S, Lee T, Baek M. 273. Single port transanal minimally invasive surgery for rectal tumours under spinal anesthesia. Eur J Surg Oncol 2014. [DOI: 10.1016/j.ejso.2014.08.265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Chung HE, Yu J, Baek M, Lee JA, Kim MS, Kim SH, Maeng EH, Lee JK, Jeong J, Choi SJ. Toxicokinetics of zinc oxide nanoparticles in rats. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/429/1/012037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Baek M, Ahn T, Jung D, Park S, Kim H, Lee W, Park D. 1146 POSTER Pro-angiogenic Factor Cyr61 is Linked to Colorectal Cancer Development and Prognosis. Eur J Cancer 2011. [DOI: 10.1016/s0959-8049(11)70789-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Kim SJ, Koo TS, Ha DJ, Baek M, Lee SK, Shin DS, Moon H. Liquid chromatography-tandem mass spectrometry for quantification of lacosamide, an antiepileptic drug, in rat plasma and its application to pharmacokinetic study. Biomed Chromatogr 2011; 26:371-6. [DOI: 10.1002/bmc.1668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/04/2011] [Accepted: 05/15/2011] [Indexed: 01/04/2023]
Affiliation(s)
- Soo-Jin Kim
- Life Science R&D Park; SK Holdings Co. Ltd; Daejeon; 305-712; Korea
| | - Tae-Sung Koo
- Life Science R&D Park; SK Holdings Co. Ltd; Daejeon; 305-712; Korea
| | - Dong-Jin Ha
- Life Science R&D Park; SK Holdings Co. Ltd; Daejeon; 305-712; Korea
| | - Myoungki Baek
- Life Science R&D Park; SK Holdings Co. Ltd; Daejeon; 305-712; Korea
| | - Sang-Kil Lee
- Department of Chemistry; Changwon National University; Changwon; 641-773; Korea
| | - Dong-Soo Shin
- Department of Chemistry; Changwon National University; Changwon; 641-773; Korea
| | - Hongsik Moon
- Life Science R&D Park; SK Holdings Co. Ltd; Daejeon; 305-712; Korea
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Baek M, Kim MK, Cho HJ, Lee JA, Yu J, Chung HE, Choi SJ. Factors influencing the cytotoxicity of zinc oxide nanoparticles: particle size and surface charge. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/304/1/012044] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Koo TS, Kim SJ, Lee J, Ha DJ, Baek M, Moon H. Quantification of lurasidone, an atypical antipsychotic drug, in rat plasma with high-performance liquid chromatography with tandem mass spectrometry. Biomed Chromatogr 2011; 25:1389-94. [PMID: 21387355 DOI: 10.1002/bmc.1625] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/24/2011] [Accepted: 01/31/2011] [Indexed: 11/07/2022]
Abstract
A liquid chromatography-tandem mass spectrometric (LC/MS/MS) method was developed for the determination of an atypical antipsychotic drug, lurasidone, in rat plasma. The method involves the addition of acetonitrile and ziprasidone (internal standard) solution to plasma samples, followed by centrifugation. An aliquot of the supernatant was diluted with water and directly injected into the LC/MS/MS system. The separations were performed on a column packed with octadecylsilica (5 μm, 2.0 × 50 mm) with 0.1% formic acid and 0.1% formic acid in acetonitrile as mobile phase and the detection was performed using tandem mass spectrometry by multiple-reaction monitoring via an electrospray ionization source. The standard curve was linear (r = 0.9982) over the concentration range 0.002-1 μg/mL. The intra- and inter-assay precisions were 1.7 and 8.6%, respectively. The accuracy range was from 90.3 to 101.8%. The lower limit of quantification was 2.0 ng/mL using 50 μL of rat plasma sample. The developed analytical method was successfully applied to the pharmacokinetic study of lurasidone in rats.
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Affiliation(s)
- Tae-Sung Koo
- Life Science R&D Park, SK Holdings Co. Ltd, Daejeon, 305-712, Korea.
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Abstract
446 Background: Angiogenic factorCysteine-rich 61 (Cyr61) is a member of the CCN protein family that has been implicated in diverse biological processes such as cell adhesion, proliferation, angiogenesis, and tumorigenesis. An altered expression of Cyr61 is found to be associated with several human cancers. However, the correlation of expression of Cyr61 protein and clinical features of colorectal cancer remains unknown. Methods: Cyr61 expression in colorectal cancer and normal tissues was evaluated by Western blot analysis. Immunohistochemical staining was carried out using tissue microassay (TMA) to examine the expression status of Cyr61. Correlations of Cyr61 over-expression with various clinicopathologic factors were also determined. Statistical analysis was performed to explore the links between expression of the Cyr61 and clinicopathological parameters. Results: On Western blot analysis Cyr61 up-regulation was observed in colorectal cancer tissues (17/21, 80.9%). In 234 colorectal cancers, tumor tissue microarray revealed significantly up-regulated Cyr61 protein expression in colorectal cancer tissues versus normal tissues adjacent to tumor. Cyr61 expression was high in 136 of 234 cases of colorectal carcinomas (58.1%). Cyr61 over-expression was significantly associated with TNM stage (p=0.012) and regional lymph node involvement (p=0.018). Kaplan-Meier survival analysis showed that over-expression of Cyr61 was related to poor survival of colorectal cancer patients (p=0.031). But significant associations were not found between CYR61 expression versus tumor grade, age and gender. Conclusions: Our results suggest that Cyr61 is highly expressed in colorectal carcinomas and Cyr61 may play a role in the progression of colorectal cancers. Also, Cyr61 might be a new molecular marker to predict the prognosis and serve as valuable targets for therapeutic intervention of patients with colorectal carcinoma. No significant financial relationships to disclose.
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Affiliation(s)
- M. Baek
- Department of Surgery, Soonchunhyang University, Cheonan, South Korea; Department of Internal Medicine, Soonchunhyang University, Cheonan, South Korea; Department of Pathology, Soonchunhyang University, Cheonan, South Korea
| | - S. Bae
- Department of Surgery, Soonchunhyang University, Cheonan, South Korea; Department of Internal Medicine, Soonchunhyang University, Cheonan, South Korea; Department of Pathology, Soonchunhyang University, Cheonan, South Korea
| | - D. Jeong
- Department of Surgery, Soonchunhyang University, Cheonan, South Korea; Department of Internal Medicine, Soonchunhyang University, Cheonan, South Korea; Department of Pathology, Soonchunhyang University, Cheonan, South Korea
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Bae S, Baek M, Jeong D, Kim C, Kim E, Shin E, Park D. Expression changes of angiogenic factors in rectal carcinomas after neoadjuvant chemoradiotherapy. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.e14061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Paick S, Lho Y, Baek M, Lee B, Kim H, Choi H. MP-12.10: The Effect of Orchiectomy on Contralateral Testicular Injury after Testicular Torsion in the Rat. Urology 2009. [DOI: 10.1016/j.urology.2009.07.897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Baek M, Ahn T, Jeong D, Cho S, Kim J, Shin E, Song O. 6103 Expression and role of placenta growth factor (PlGF) on colorectal carcinomas. EJC Suppl 2009. [DOI: 10.1016/s1359-6349(09)71198-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Baek M, Chu C, Song O, Shin E, Park D. The association of expression level of PRL-3 mRNA and liver metastasis in primary colorectal cancer. EJC Suppl 2008. [DOI: 10.1016/s1359-6349(08)71653-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Lho Y, Paick S, Baek M, Park W, Kim H. POS-02.67: The efficacy of transurethral resection of the prostate in patients with large prostate (over 80 g). Urology 2007. [DOI: 10.1016/j.urology.2007.06.708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Sermsappasuk P, Baek M, Weiss M. Kinetic analysis of myocardial uptake and negative inotropic effect of amiodarone in rat heart. Eur J Pharm Sci 2006; 28:243-8. [PMID: 16574386 DOI: 10.1016/j.ejps.2006.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 02/02/2006] [Accepted: 02/20/2006] [Indexed: 10/24/2022]
Abstract
The distribution kinetics of the highly lipophilic antiarrhythmic agent amiodarone is not well understood. The purpose of the present investigation was to develop a pharmacokinetic-pharmacodynamic (PK/PD) model to describe cardiac uptake and the negative inotropic effect of amiodarone in the isolated perfused rat heart. Amiodarone (10 microM) was infused for 15 min to 6 hearts. The time course of outflow concentration and left ventricular developed pressure were measured and analyzed by the model. The uptake of amiodarone by the heart was flow limited and characterized by an extremely high partition coefficient with a predicted tissue washout half-live of 17 h. Only 36.8% of input amount to heart recovered within 45 min after start of the 15 min infusion. The negative inotropic effect was delayed with a time constant of 11 min and the maximal decrease in left ventricular developed pressure was described by a sigmoid E(max) model with an E(max) of 37.7% and an EC(50) of 0.53 microM. Our results suggest a rapid tissue uptake and a moderate negative inotropic effect of amiodarone after intravenous injection.
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Affiliation(s)
- Pakawadee Sermsappasuk
- Section of Pharmacokinetics, Department of Pharmacology, Martin Luther University Halle-Wittenberg, D-06097 Halle, Germany
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Seo HR, Lee DH, Lee HJ, Baek M, Bae S, Soh JW, Lee SJ, Kim J, Lee YS. Cyclin G1 overcomes radiation-induced G2 arrest and increases cell death through transcriptional activation of cyclin B1. Cell Death Differ 2005; 13:1475-84. [PMID: 16322753 DOI: 10.1038/sj.cdd.4401822] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Although cyclin G1 has been implicated in certain p53-related biological phenomena, other aspects of its function remain unclear. Here we report hitherto unknown mechanism by which cyclin G1 increases radiation sensitivity by regulating the level of cyclin B1. Overexpression of cyclin G1 was observable in lung carcinoma tissues. Irradiation of human lung cells with cyclin G1 overexpression resulted in increased cell death and gamma-H2AX foci suggesting that cyclin G1 rendered the cells more susceptible to DNA damage. Enhanced radiosensitivity by cyclin G1 was correlated with increased cyclin B1, CDC2/cyclin B1 complex, and MPM2. Cell cycle synchronization clearly showed coexpression of cyclin G1 and cyclin B1 in G2/M phase. Depletion of cyclin G1 by interference RNA revealed that cyclin G1 regulated transcription of cyclin B1 in a p53-independent manner, and confirmed that the increased mitotic cells and cell death by cyclin G1 were dependent upon cyclin B1. Therefore, our data suggest that cyclin G1 enhanced radiation sensitivity by overriding radiation-induced G2 arrest through transcriptional upregulation of cyclin B1.
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Affiliation(s)
- H R Seo
- Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, 215-4 Gongneung-Dong, Nowon-Ku, Seoul 139-706, Korea
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Lee HW, Won KJ, Cho SH, Ha YH, Park WS, Yim HT, Baek M, Rew JH, Yoon SH, Yim SV, Chung JH, Lee KT. Quantitation of niflumic acid in human plasma by high-performance liquid chromatography with ultraviolet absorbance detection and its application to a bioequivalence study of talniflumate tablets. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 821:215-20. [PMID: 15921965 DOI: 10.1016/j.jchromb.2005.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 05/11/2005] [Indexed: 11/18/2022]
Abstract
A rapid and simple HPLC method with UV detection (288 nm) was developed and validated for quantitation of niflumic acid in human plasma, the active metabolite of talniflumate. After precipitation with 100% methanol containing the internal standard, indomethacin, the analysis of the niflumic acid level in the plasma samples was carried out using a reverse phase C18 CAPCELL PAK (5 microm, 4.6 mm x 250 mm) column. The chromatographic separation was accomplished with an isocratic mobile phase consisting of a mixture of 0.1M sodium acetate in water and acetonitrile (37:63, v/v), adjusted to pH 6.4. This HPLC method was validated by examining its precision and accuracy for inter- and intra-day runs in a linear concentration range of 0.02-5.00 microg/mL. Stability of niflumic acid in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method was successfully applied to the bioequivalence study of talniflunate in healthy volunteers.
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Affiliation(s)
- H W Lee
- Department of Biochemistry, College of Pharmacy, Kyung Hee University, Hoegi-Dong, Dongdaemun-Ku, Seoul 130-701, Republic of Korea
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23
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Li JH, Sicard F, Salam MA, Baek M, LePrince J, Vaudry H, Kim K, Kwon HB, Seong JY. Molecular cloning and functional characterization of a type-I neurotensin receptor (NTR) and a novel NTR from the bullfrog brain. J Mol Endocrinol 2005; 34:793-807. [PMID: 15956348 DOI: 10.1677/jme.1.01709] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neurotensin (NT) is a tridecapeptide that functions as a neurotransmitter and neuromodulator in the nervous system. To date, three different types of NT receptor (NTR), NTR1, NTR2 and NTR3, have been identified only in mammalian species. In the present study we isolated the cDNAs for an NTR1 and a novel NTR in the bullfrog brain, designated bfNTR1 and bfNTR4 respectively. bfNTR1 and bfNTR4 encode 422- and 399-amino acid residue proteins respectively. bfNTR1 has a 64% amino acid identity with mammalian NTR1, and 34-37% identity with mammalian NTR2. bfNTR4 exhibits 43% and 45-47% identity with mammalian NTR1 and NTR2 respectively. Both receptors are mainly expressed in the brain and pituitary. bfNTR1 triggers both CRE-luc, a protein kinase A (PKA)-specific reporter, and c-fos-luc, a PKC-specific reporter, activities, indicating that bfNTR1 can activate PKA- and PKC-linked signaling pathways. However, bfNTR4 appears to be preferentially coupled to the PKA-linked pathway as it induces a higher CRE-luc activity than c-fos-luc activity. bfNTRs exhibit different pharmacological properties as compared with mammalian NTRs. Mammalian NTR1 but not NTR2 responds to NT, whereas both bfNTR1 and bfNTR4 show a high sensitivity to NT. SR 48692 and SR 142948A, antagonists for mammalian NTR1 but agonists for mammalian NTR2, function as antagonists for both bfNTR1 and bfNTR4. In conclusion, this report provides the first molecular, pharmacological and functional characterization of two NTRs in a non-mammalian vertebrate. These data should help to elucidate the phylogenetic history of the G protein-coupled NTRs in the vertebrate lineage as well as the structural features that determine their pharmacological properties.
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Affiliation(s)
- J H Li
- Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
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24
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Baek M, Weiss M. Mechanism-based modeling of reduced inotropic responsiveness to digoxin in endotoxemic rat hearts. Eur J Pharmacol 2005; 514:43-51. [PMID: 15878323 DOI: 10.1016/j.ejphar.2005.03.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/15/2005] [Accepted: 03/18/2005] [Indexed: 10/25/2022]
Abstract
The mechanisms by which endotoxemia affects myocardial contractility and responsiveness to inotropic drugs are not well understood. We examined the positive inotropic effect of digoxin in single-pass Langendorff-perfused hearts from rats after in vivo pretreatment with lipopolysaccharide (LPS, 4 mg/kg, i.p., 4 h before heart isolation). Using a mathematical modeling approach that allows differentiation between effects elicited at the receptor and postreceptor level, we studied uptake, receptor binding and effectuation kinetics after three consecutive digoxin doses (15, 30, and 45 microg) in the absence and presence of the reverse mode Na(+)/Ca(2+) exchange (NCX) inhibitor KB-R7943 (0.1 microM) in perfusate. LPS significantly depressed baseline contractility and the inotropic response to digoxin without affecting its uptake mechanism. Compared with the control group, the slope of the functional receptor occupancy (stimulus)-to-response relationship was reduced by 44% in the LPS group. Model analysis revealed a significant correlation between changes in digoxin action and LPS-induced febrile response: digoxin receptor affinity increased and the response/stimulus ratio decreased with rise in body temperature, respectively. In contrast, the diminished responsiveness to digoxin observed after NCX inhibition in the control group was not further attenuated in the LPS group. These results support the hypothesis that postreceptor events may be responsible for the diminished contractile response to digoxin during endotoxemia.
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Affiliation(s)
- Myoungki Baek
- Section of Pharmacokinetics, Department of Pharmacology, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
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25
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Baek M, Weiss M. Down-Regulation of Na+Pump α2Isoform in Isoprenaline-Induced Cardiac Hypertrophy in Rat: Evidence for Increased Receptor Binding Affinity but Reduced Inotropic Potency of Digoxin. J Pharmacol Exp Ther 2005; 313:731-9. [PMID: 15644428 DOI: 10.1124/jpet.104.078345] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cardiac hypertrophy in rats induces a down-regulation of Na(+),K(+)-ATPase alpha(2) isoform, although its functional consequences are poorly understood. Using a mathematical modeling approach that allows differentiation between effects elicited at the receptor and postreceptor level, we studied uptake, receptor binding kinetics, and positive inotropism of digoxin in single-pass Langendorff-perfused hearts of vehicle- and isoprenaline-pretreated rats (2.4 mg/kg per day over 4 days). Digoxin outflow concentration and left ventricular developed pressure data were measured for three consecutive doses (15, 30, and 45 microg) in the absence and presence of the reverse mode Na(+)/Ca(2+) exchange inhibitor 2-[2-[4-(4-nitrobenzyloxyl-)phenyl]ethyl isothiourea methansulfonate] (KB-R7943) (0.1 microM) in perfusate. In hypertrophied hearts, 1) the amount of alpha(2) receptors was reduced to 52% of control levels; 2) the digoxin binding affinity was increased 12-fold due to a decrease in dissociation rate constants of alpha(1) and alpha(2) receptors, and 3) inotropic responsiveness to digoxin the was attenuated on the stimulus-response level, where the coupling ratio of stimulus to response was reduced to 38% of control values. Only in the lowest dose level (15 microg) was this decrease in inotropic potency counterbalanced by the increase in receptor affinity. The Na(+),K(+)-ATPase isoform shift was not responsible for the diminished inotropic effect of digoxin. Coadministration of KB-R7943 significantly reduced cellular response generation at higher digoxin doses to the same limiting stimulus-response relationship in both the vehicle and isoprenaline group.
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Affiliation(s)
- Myoungki Baek
- Section of Pharmacokinetics, Department of Pharmacology, Martin Luther University Halle-Wittenberg, Germany
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26
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Abstract
To gain more insight into the mechanistic processes controlling the kinetics of inotropic response of digoxin in the perfused whole heart, an integrated kinetic model was developed incorporating digoxin uptake, receptor binding (Na(+)-K(+)-ATPase inhibition), and cellular events linking receptor occupation and response. The model was applied to data obtained in the single-pass Langendorff-perfused rat heart for external [Ca(2+)] of 0.5 and 1.5 mM under control conditions and in the presence of the reverse-mode Na(+)/Ca(2+) exchange inhibitor KB-R7943 (0.1 microM) in perfusate. Outflow concentration and left ventricular developed pressure data measured for three consecutive doses (15, 30, and 45 microg) in each heart were analyzed simultaneously. While disposition kinetics of digoxin was determined by interaction with a heterogeneous receptor population consisting of a high-affinity/low-capacity and a low-affinity/high- capacity binding site, response generation was >80% mediated by binding to the high-affinity receptor. Digoxin sensitivity increased at lower external [Ca(2+)] due to higher stimulus amplification. Coadministration of KB-R7943 significantly reduced the positive inotropic effect of digoxin at higher doses (30 and 45 microg) and led to a saturated and delayed receptor occupancy-response relationship in the cellular effectuation model. The results provide further evidence for the functional heterogeneity of the Na(+)-K(+)-ATPase and suggest that in the presence of KB-R7943 a reduction of the Ca(2+) influx rate via the reverse mode Na(+)/Ca(2+) exchanger might become the limiting factor in digoxin response generation.
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Affiliation(s)
- Michael Weiss
- Section of Pharmacokinetics, Dept. of Pharmacology, Martin Luther Univ. Halle-Wittenberg, D-06097 Halle, Germany.
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27
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Patten L, Belaguli N, Baek M, Berger D. Serum response factor is alternatively spliced in colon cancer. J Surg Res 2003. [DOI: 10.1016/j.jss.2003.08.168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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28
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Kim JY, Baek M, Lee S, Kim SO, Dong MS, Kim BR, Kim DH. Characterization of the selectivity and mechanism of cytochrome P450 inhibition by dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate. Drug Metab Dispos 2001; 29:1555-60. [PMID: 11717174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
In vitro studies with human liver microsomes and cytochrome P450 (P450) prototype substrates were performed to characterize the selectivity and mechanism of inhibition of P450 by dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate (DDB). DDB was found to be a strong inhibitor of testosterone 6beta-hydroxylation activity (CYP3A4) with a K(i) value of 0.27 +/- 0.21 microM. At higher concentrations, DDB marginally inhibited caffeine N(3)-demethylation (CYP1A2), diclofenac 4'-hydroxylation (CYP2C9), and dextromethorphan O-demethylation (CYP2D6) activities, but this compound had no effect on CYP2A6-, CYP2C19-, and CYP2E1-mediated reactions. Spectral analysis indicated that the formation of metabolite-P450 complex having absorbance at 456 nm was concentration-dependent; 5 to 33% of the total P450 was complexed in rat and human liver microsomes after a 5-min incubation with DDB. In addition, microsomal incubations with DDB in the presence of NADPH resulted in a loss of spectral P450 content, which was restored after adding K(3)Fe(CN)(6). This complex formation resulted in a time-dependent loss of CYP3A-catalyzed marker activity (testosterone 6beta-hydroxylation) in human liver microsomes. The inhibition was only partially restored upon dialysis. These results collectively suggest that formation of a metabolite-CYP3A complex with DDB was responsible for the CYP3A-selective time-dependent loss of catalytic function of CYP3A.
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Affiliation(s)
- J Y Kim
- Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, Chungryang, Seoul, Korea
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29
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Bae Y, Kim H, Namgoong H, Baek M, Lee J, Hwang D, Hwang Y, Ahn C, Kang S. Characterization of microsatellite markers adjacent to AP-4 on chromosome 16p13.3. Mol Cell Probes 2001; 15:313-5. [PMID: 11735304 DOI: 10.1006/mcpr.2001.0375] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 1400 kb genomic sequence between the markers D16S406 and D16S423 on chromosome 16p13.3 has been recently sequenced and the interval contains a transcription factor, AP-4, that was identified as a ligand for immunoglobulin-kappa promoter E-box elements,(1)suggesting that AP-4 may be related to immunodeficiency diseases. In addition, chromosome 16p13.3 includes a number of genes including the PKD1 gene,(2,3)the autosomal dominant polycystic kidney disease (ADPKD) gene. ADPKD is characterized by progressive development and enlargement of renal cysts.(4)The size and genomic complexity of the PKD1 gene makes it impractical to detect mutations for prenatal diagnosis. Therefore, pedigree-based linkage analysis remains useful for diagnosis of ADPKD. To increase the number of polymorphic markers in the region around AP-4 gene, we performed database searches of 1400 kb of genomic sequence (from contig NT000677 to NT001573: http://www.ncbi.gov/genome/seq.cgi) across the 16p13.3. A number of dinucleotide or tetranucleotide repeats were found, and 20 microsatellites that contain more than 15 contiguous repeats were chosen for further investigation.
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Affiliation(s)
- Y Bae
- Graduate School of Biotechnology, Korea University, Seoul 136-701, Korea
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30
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Abstract
In this genomics and proteomics age, highly functionalized natural products or natural-product-like compounds are likely to play important roles in understanding the functions of emerging biological targets because they serve as small-molecule chemical probes in modulating a target's specific actions (i.e. activation or deactivation). Development of stereoselective reaction-derived methods on solid phase provides a means of obtaining functionalized chiral core structures that may be used for high-throughout syntheses.
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Affiliation(s)
- P Arya
- Chemical Biology Program, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, K1A 0R6, Ottawa, Ontario, Canada.
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31
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Baek M, Jeong JH, Kim DH. Determination of aloesin in rat plasma using a column-switching high-performance liquid chromatographic assay. J Chromatogr B Biomed Sci Appl 2001; 754:121-6. [PMID: 11318406 DOI: 10.1016/s0378-4347(00)00593-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A column-switching high-performance liquid chromatography (HPLC) method for the determination of aloesin in rat plasma using column-switching and ultraviolet (UV) absorbance detection is described. Plasma was directly injected onto the HPLC system consisting of a clean-up column, a concentrating column, and an analytical column, which were connected with a six-port switching valve. The determination of aloesin was accurate and repeatable, with a limit of quantitation of 10 ng/ml in plasma. The standard calibration curve for aloesin was linear (r=0.998) over the concentration range of 10-1000 ng/ml in rat plasma. The intra- and inter-day assay variabilities of aloesin ranged from 1.0 to 4.7% and 1.1 to 8.8%, respectively. This highly sensitive and simple method has been successfully applied to a pharmacokinetic study after oral administration of aloesin to rats.
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Affiliation(s)
- M Baek
- Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, Seoul, South Korea
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32
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Baek M, Rho YS, Kim DH. Column-switching high-performance liquid chromatographic assay for determination of asiaticoside in rat plasma and bile with ultraviolet absorbance detection. J Chromatogr B Biomed Sci Appl 1999; 732:357-63. [PMID: 10517358 DOI: 10.1016/s0378-4347(99)00302-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A column-switching high-performance liquid chromatography (HPLC) method is described for the determination of asiaticoside in rat plasma and bile using column-switching and ultraviolet (UV) absorbance detection. Plasma was simply deproteinated with acetonitrile prior to injection and bile was directly injected onto the HPLC system consisting of a clean-up column, a concentrating column, and an analytical column, which were connected with two six-port switching valves. Detection of asiaticoside was accurate and repeatable, with a limit of quantification of 0.125 microg/ml in plasma and 1 microg/ml in bile. The calibration curves were linear in a concentration range of 0.125-2.5 microg/ml and 1-20 microg/ml for asiaticoside in rat plasma and bile, respectively. This method has been successfully applied to determine the level of asiaticoside in rat plasma and bile samples from pharmacokinetics and biliary excretion studies.
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Affiliation(s)
- M Baek
- Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, Seoul, South Korea
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33
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Baek M, Chung HS, Kim Y, Kim DH. Disposition and metabolism of 2-(2''(1'',3''-dioxolan-2-yl)-2- methyl-4-(2'-oxopyrrolidin-1-Yl)-6-nitro-2h-1-benzopyran (SKP-450) in rats. Drug Metab Dispos 1999; 27:510-6. [PMID: 10101146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
The disposition and metabolism of the new antihypertensive agent 2-(2"(1", 3"-dioxolan-2-yl)-2-methyl-4-(2'-oxopyrrolidin-1-yl)-6-nitro -2H-1-benzopyran (SKP-450) were investigated in male rats after single oral and i.v. doses of 14C-labeled compound. After an oral 2.0 mg/kg dose, mean radiocarbon recovery was 98.2 +/- 2.3% with 31.1 +/- 7.3% in the feces and 67.1 +/- 14.3% in the urine. Biliary excretion of radioactivity for the first 24-h period was approximately 40%, suggesting that SKP-450 is cleared either by hepatobiliary excretion or by renal excretion. SKP-450 was well absorbed; bioavailability calculated on the basis of radioactivity was 68 to 97%. Tissue distribution of the radioactivity was widespread with high concentrations in the liver and kidney but low central nervous system penetration. Radio-HPLC analysis of bile and urine from rats indicated the extensive metabolism of SKP-450 into oxidative metabolites. Oxidative metabolism of the dioxolanyl ring resulted in an aldehyde intermediate, subsequently confirmed in vitro, which was further oxidized to the corresponding carboxylic acid (M1) or reduced to the corresponding alcohol (M3). No parent drug was detected in the urine or bile. Glucuronide conjugate of M3 was also detected in urine and bile, accounting for 5.8 +/- 2.1 and 8.9 +/- 3. 7% of the excreted radioactivity, respectively. Quantitative data obtained from plasma samples suggest that the majority of circulating radioactivity was associated with metabolites. Our results suggest that the long duration of pharmacological activity of SKP-450 (>10 h) is largely attributable to its metabolites.
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Affiliation(s)
- M Baek
- Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, Chungryang, Seoul, Korea
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