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Sakon K, Sasaki M, Tanaka K, Mizunaga T, Yano K, Kawamura Y, Okada A, Ikeda T, Tanabe S, Takamori A, Yamada N, Morioka K, Koshiji T. Intratumoral gene expression of dihydrofolate reductase and folylpoly-c-glutamate synthetase affects the sensitivity to 5-fluorouracil in non-small cell lung cancer. Discov Oncol 2021; 12:19. [PMID: 35201464 PMCID: PMC8777502 DOI: 10.1007/s12672-021-00413-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/16/2021] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Various factors related to the sensitivity of non-small cell lung carcinoma (NSCLC) to 5-fluorouracil (5-FU) have been reported, and some of them have been clinically applied. In this single-institutional prospective analysis, the mRNA expression level of five folic acid-associated enzymes was evaluated in surgical specimens of NSCLC. We investigated the correlation between the antitumor effect of 5-FU in NSCLC using an anticancer drug sensitivity test and the gene expression levels of five enzymes. MATERIALS AND METHODS Forty patients who underwent surgery for NSCLC were enrolled, and the antitumor effect was measured using an in vitro anticancer drug sensitivity test (histoculture drug response assay) using freshly resected specimens. In the same sample, the mRNA expression levels of five enzymes involved in the sensitivity to 5-FU were measured in the tumor using real-time PCR. The expression levels and the result of the sensitivity test were compared. RESULTS No correlation was found between dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), or DPD/OPRT expression and the antitumor effects of 5-FU. On the other hand, a correlation was found between thymidylate synthase (TS), folylpoly-c-glutamate synthetase (FPGS), and dihydrofolate reductase (DHFR) expression and 5-FU sensitivity. CONCLUSION Expression of FPGS and DHFR may be useful for predicting the efficacy of 5-FU-based chemotherapy for NSCLC.
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Affiliation(s)
- Kayo Sakon
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Masato Sasaki
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Kaede Tanaka
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Tae Mizunaga
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Keita Yano
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Yuuko Kawamura
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Akitoshi Okada
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Takeshi Ikeda
- Department of Thoracic Surgery, National Center for Global Health and Medicine, 1-21-1 Toyama Shinjyuku-ku, Tokyo, 162-8655 Japan
| | - Sawaka Tanabe
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Atsushi Takamori
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Narihisa Yamada
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Kouichi Morioka
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
| | - Takaaki Koshiji
- Department of Surgery (II), Faculty of Medical Sciences, University of Fukui, 23-3 Shimoaizuki, Matsuoka Eiheijichou, Fukui, 910-1193 Japan
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Skariyachan S, Muddebihalkar AG, Badrinath V, Umashankar B, Eram D, Uttarkar A, Niranjan V. Natural epiestriol-16 act as potential lead molecule against prospective molecular targets of multidrug resistant Acinetobacter baumannii-Insight from in silico modelling and in vitro investigations. Infect Genet Evol 2020; 82:104314. [PMID: 32268193 DOI: 10.1016/j.meegid.2020.104314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 03/05/2020] [Accepted: 04/01/2020] [Indexed: 01/09/2023]
Abstract
The current study aimed to identify putative drug targets of multidrug resistant Acinetobacter baumannii (MDRAb) and study the therapeutic potential of natural epiestriol-16 by computer aided virtual screening and in vitro studies. The clinical isolates (n = 5) showed extreme dug resistance to carbapenems and colistins (p ≤ .05). Computational screening suggested that out of 236 natural molecules selected, 06 leads were qualified for drug likeliness, pharmacokinetic features and one potential molecule namely natural epiestriol-16 (16b-Hydroxy-17a-estradiol) exhibited significant binding potential towards four prioritised drug targets in comparison with the binding of faropenem to their usual target. Natural epiestriol demonstrated profound binding to the outer membrane protein (Omp38), protein RecA (RecA), orotate phosphoribosyltransferase (PyrE) and orotidine 5'-phosphate decarboxylase (PyrF) with binding energy of -6.0, -7.3, -7.3 and -8.0 kcal/mol respectively. MD simulations suggested that 16-epiestriol-receptor complexes demonstrated stability throughout the simulation. The growth curve and time kill assays revealed that MDRAb showed resistance to faropenem and polymyxin-B and the pure epiestriol-16 showed significant inhibitory properties at a concentration of 200 μg/mL (p ≤ .5). Thus, natural epiestriol-16 can be used as potential inhibitor against the prioritised targets of MDRAb and this study provide insight for drug development against carbapenem and colistin resistant A. baumannii.
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Affiliation(s)
- Sinosh Skariyachan
- Department of Microbiology, St. Pius X College Rajapuram, Kasaragod, Kerala, India; Department of Biotechnology, Dayananda Sagar College of Engineering, Bangalore, Karnataka, India.
| | - Aditi G Muddebihalkar
- Department of Biotechnology, Dayananda Sagar College of Engineering, Bangalore, Karnataka, India
| | - Vaishnavi Badrinath
- Department of Biotechnology, Dayananda Sagar College of Engineering, Bangalore, Karnataka, India
| | - Bindu Umashankar
- Department of Biotechnology, Dayananda Sagar College of Engineering, Bangalore, Karnataka, India
| | - Daniya Eram
- Department of Biotechnology, Dayananda Sagar College of Engineering, Bangalore, Karnataka, India
| | - Akshay Uttarkar
- Department of Biotechnology, RV College of Engineering, Bangalore, Karnataka, India
| | - Vidya Niranjan
- Department of Biotechnology, RV College of Engineering, Bangalore, Karnataka, India
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Abstract
Computational investigation of orotate phosphoribosyltransferase (OPRT) action, an enzymatic reaction between phosphoribosyl pyrophosphate (PRPP) and orotic acid (OA) to yield orotidine 5'-monophosphate (OMP), was carried out. Insights into the pathways of the substrate attack step of the reaction were developed under the quantum mechanics/molecular mechanics framework with S. cerevisiae strain as the representative enzyme bearer. Four pathways were proposed for PRPP and OA binding differing in the sequence of PRPP, OA and Mg2+ ion complexation with OPRT. The formation of Mg2+-OPRT complex was accompanied by a small energy change while the largest stabilization was observed for the formation of Mg2+-PRPP complex supporting the experimental observation of Mg2+-PRPP complex as the true substrate for the reaction. Formation of PRPP-OPRT complex was found to be energetically not probable rendering the pathway requiring Mg2+-OA complex not probable. Further, PRPP migration towards the active site was found to be energetically not favoured rendering the pathway involving Mg2+-OA complexation improbable. Migration of OA and Mg2+-PRPP complex towards the active site was found to be energetically probable with a large stabilization of the system when Mg2+-PRPP complex bound to the OA-OPRT complex. This conclusively proved the sequential binding of OA and Mg2+-PRPP complexes during OPRT action.
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Affiliation(s)
- N N Subrahmanyeswara Rao
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Parag A Deshpande
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
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Paojinda P, Imprasittichai W, Krungkrai SR, Palacpac NMQ, Horii T, Krungkrai J. Bifunctional activity of fused Plasmodium falciparum orotate phosphoribosyltransferase and orotidine 5'-monophosphate decarboxylase. Parasitol Int 2017; 67:79-84. [PMID: 28389349 DOI: 10.1016/j.parint.2017.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 10/19/2022]
Abstract
Fusion of the last two enzymes in the pyrimidine biosynthetic pathway in the inversed order by having a COOH-terminal orotate phosphoribosyltransferase (OPRT) and an NH2-terminal orotidine 5'-monophosphate decarboxylase (OMPDC), as OMPDC-OPRT, are described in many organisms. Here, we produced gene fusions of Plasmodium falciparum OMPDC-OPRT and expressed the bifunctional protein in Escherichia coli. The enzyme was purified to homogeneity using affinity and anion-exchange chromatography, exhibited enzymatic activities and functioned as a dimer. The activities, although unstable, were stabilized by its substrate and product during purification and long-term storage. Furthermore, the enzyme expressed a perfect catalytic efficiency (kcat/Km). The kcat was selectively enhanced up to three orders of magnitude, while the Km was not much affected and remained at low μM levels when compared to the monofunctional enzymes. The fusion of the two enzymes, creating a "super-enzyme" with perfect catalytic power and more flexibility, reflects cryptic relationship of enzymatic reactivities and metabolic functions on molecular evolution.
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Affiliation(s)
- Patsarawadee Paojinda
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; Inter-Department Program of Biomedical Science, Faculty of Graduate School, Chulalongkorn University, Bangkok 10330, Thailand
| | - Waranya Imprasittichai
- Department of Basic Medical Science, Faculty of Medicine Vajira Hospital, Navamindradhiraj University, Bangkok 10300, Thailand
| | - Sudaratana R Krungkrai
- Unit of Biochemistry, Department of Medical Science, Faculty of Science, Rangsit University, Patumthani 12000, Thailand
| | - Nirianne Marie Q Palacpac
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Jerapan Krungkrai
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
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Eguchi K, Oyama T, Tajima A, Abiko T, Sawafuji M, Horio H, Hashizume T, Matsutani N, Kato R, Nakayama M, Kawamura M, Kobayashi K. Intratumoral gene expression of 5-fluorouracil pharmacokinetics-related enzymes in stage I and II non-small cell lung cancer patients treated with uracil-tegafur after surgery: a prospective multi-institutional study in Japan. Lung Cancer 2014; 87:53-8. [PMID: 25468199 DOI: 10.1016/j.lungcan.2014.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 09/22/2014] [Accepted: 10/23/2014] [Indexed: 11/15/2022]
Abstract
OBJECTIVES This investigation was conducted to assess the use of the intratumoral mRNA expression levels of nucleic acid-metabolizing enzymes as biomarkers of adjuvant chemotherapy for non-small cell lung cancer (NSCLC) using uracil-tegafur in a multi-institutional prospective study. MATERIALS AND METHODS 236 patients with a completely resected NSCLC (adenocarcinoma and squamous cell carcinoma) of pathological stage IA (maximum tumor diameter of 2 cm or greater), IB, and II tumors were given a dose of 250 mg of uracil-tegafur per square meter of body surface area per day orally for two years after surgery. Intratumoral mRNA levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), and thymidine phosphorylase (TP) genes relative to an internal standard, β-actin, were determined using laser-capture microdissection and fluorescence-based real time PCR detection systems. RESULTS AND CONCLUSION Among 5-FU target enzymes, TS was the only one that showed a significant difference in the level of gene expression between the high and low gene expression groups, for both disease-free survival (DFS) and overall survival (OS), when patients were divided according to median values; 5-year DFS rates in high/low TS gene expression were 60.4% and 72.6%, respectively (p=0.050), 5-year OS rates were 78.1% and 88.6%, respectively (p=0.011). Cox's proportional hazard model indicated that the pathological stage and TS gene expression level were independent values for predicting DFS. The TS gene expression level was shown to be an independent predictive factor for DFS in stage I and II NSCLC patients who were treated with uracil-tegafur following surgery.
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Affiliation(s)
- Keisuke Eguchi
- Department of General Thoracic Surgery, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama 350-8550, Japan; Department of General Thoracic Surgery, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki, Kanagawa 210-0013, Japan
| | - Takahiko Oyama
- Department of Pulmonology, National Hospital Organization, Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan
| | - Atsushi Tajima
- Department of General Thoracic Surgery, Saiseikai Utsunomiya Hospital, Tochigi, 911-1 Takebayashi, Utsunomiya, Tochigi 321-0974, Japan
| | - Tomohiro Abiko
- Department of General Thoracic Surgery, Kawasaki Municipal Ida Hospital, 1272 Ida, Nakahara-ku, Kawasaki, Kanagawa 211-0035, Japan
| | - Makoto Sawafuji
- Department of General Thoracic Surgery, Kawasaki Municipal Hospital, 12-1 Shinkawadori, Kawasaki-ku, Kawasaki, Kanagawa 210-0013, Japan
| | - Hirotoshi Horio
- Department of General Thoracic Surgery, Tokyo Metropolitan Cancer and Infectious Disease Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8677, Japan
| | - Toshinori Hashizume
- Department of General Thoracic Surgery, National Hospital Organization, Ibaraki-higashi Hospital, Ibaraki, Japan
| | - Noriyuki Matsutani
- Department of Surgery, School of Medicine Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Ryoichi Kato
- Department of Pulmonology, National Hospital Organization, Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo 152-8902, Japan
| | - Mitsuo Nakayama
- Department of General Thoracic Surgery, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama 350-8550, Japan
| | - Masafumi Kawamura
- Department of Surgery, School of Medicine Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
| | - Koichi Kobayashi
- Division of General Thoracic Surgery, School of Medicine Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Imprasittichail W, Roytrakul S, Krungkrai SR, Krungkrail J. A unique insertion of low complexity amino acid sequence underlies protein-protein interaction in human malaria parasite orotate phosphoribosyltransferase and orotidine 5'-monophosphate decarboxylase. ASIAN PAC J TROP MED 2014; 7:184-92. [PMID: 24507637 DOI: 10.1016/s1995-7645(14)60018-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 09/15/2013] [Accepted: 01/15/2014] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To investigate the multienzyme complex formation of human malaria parasite Plasmodium falciparum (P. falciparum) orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC), the fifth and sixth enzyme of the de novo pyrimidine biosynthetic pathway. Previously, we have clearly established that the two enzymes in the malaria parasite exist physically as a heterotetrameric (OPRT)2(OMPDC)2 complex containing two subunits each of OPRT and OMPDC, and that the complex have catalytic kinetic advantages over the monofunctional enzyme. METHODS Both enzymes were cloned and expressed as recombinant proteins. The protein-protein interaction in the enzyme complex was identified using bifunctional chemical cross-linker, liquid chromatography-mass spectrometric analysis and homology modeling. RESULTS The unique insertions of low complexity region at the α 2 and α 5 helices of the parasite OMPDC, characterized by single amino acid repeat sequence which was not found in homologous proteins from other organisms, was located on the OPRT-OMPDC interface. The structural models for the protein-protein interaction of the heterotetrameric (OPRT)2(OMPDC)2 multienzyme complex were proposed. CONCLUSIONS Based on the proteomic data and structural modeling, it is surmised that the human malaria parasite low complexity region is responsible for the OPRT-OMPDC interaction. The structural complex of the parasite enzymes, thus, represents an efficient functional kinetic advantage, which in line with co-localization principles of evolutional origin, and allosteric control in protein-protein-interactions.
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Affiliation(s)
- Waranya Imprasittichail
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sittiruk Roytrakul
- National Center for Genetic Engineering and Biotechnology, Pathumthani 12120, Thailand
| | - Sudaratana R Krungkrai
- Unit of Biochemistry, Department of Medical Science, Faculty of Science, Rangsit University, Pathumthani 12000, Thailand
| | - Jerapan Krungkrail
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
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Hansen MR, Barr EW, Jensen KF, Willemoës M, Grubmeyer C, Winther JR. Catalytic site interactions in yeast OMP synthase. Arch Biochem Biophys 2013; 542:28-38. [PMID: 24262852 DOI: 10.1016/j.abb.2013.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 11/15/2022]
Abstract
The enigmatic kinetics, half-of-the-sites binding, and structural asymmetry of the homodimeric microbial OMP synthases (orotate phosphoribosyltransferase, EC 2.4.2.10) have been proposed to result from an alternating site mechanism in these domain-swapped enzymes [R.W. McClard et al., Biochemistry 45 (2006) 5330-5342]. This behavior was investigated in the yeast enzyme by mutations in the conserved catalytic loop and 5-phosphoribosyl-1-diphosphate (PRPP) binding motif. Although the reaction is mechanistically sequential, the wild-type (WT) enzyme shows parallel lines in double reciprocal initial velocity plots. Replacement of Lys106, the postulated intersubunit communication device, produced intersecting lines in kinetic plots with a 2-fold reduction of kcat. Loop (R105G K109S H111G) and PRPP-binding motif (D131N D132N) mutant proteins, each without detectable enzymatic activity and ablated ability to bind PRPP, complemented to produce a heterodimer with a single fully functional active site showing intersecting initial velocity plots. Equilibrium binding of PRPP and orotidine 5'-monophosphate showed a single class of two binding sites per dimer in WT and K106S enzymes. Evidence here shows that the enzyme does not follow half-of-the-sites cooperativity; that interplay between catalytic sites is not an essential feature of the catalytic mechanism; and that parallel lines in steady-state kinetics probably arise from tight substrate binding.
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Affiliation(s)
- Michael Riis Hansen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Eric W Barr
- Department of Biochemistry, Temple University School of Medicine, 3307 N Broad St., Philadelphia, PA 19140, USA
| | - Kaj Frank Jensen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Martin Willemoës
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Charles Grubmeyer
- Department of Biochemistry, Temple University School of Medicine, 3307 N Broad St., Philadelphia, PA 19140, USA.
| | - Jakob R Winther
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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Abstract
AIM: To prove that the protein expression level of thymidylate synthase is a predictive factor for the response to S-1/cisplatin (CDDP) chemotherapy in gastric cancer.
METHODS: We measured the protein expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase (OPRT) in advanced gastric cancer. Before S-1/CDDP chemotherapy, tumor specimens from primary sites were obtained by endoscopic biopsy and analyzed by enzyme-linked immunosorbent assay. The chemotherapeutic effects on the primary sites were evaluated by endoscopic biopsy performed more than once after S-1/CDDP chemotherapy. The effects are a predictive factor for the response to S-1/CDDP chemotherapy in patients with advanced gastric cancer, as evaluated by endoscopic biopsy over time.
RESULTS: The protein expression level of TS was significantly higher (P < 0.05) in the tumor than in the normal tissue, and significantly lower (P < 0.05) in the responders than in the non-responders. We were able to evaluate the correlation between changes in the protein expression levels of TS, DPD and OPRT and chemotherapeutic responses in 7 patients by assessing tumor tissues more than twice. In the responders, the protein expression level of TS was < 40 ng/mg protein. However, there were significant increases in the protein expression levels of TS (P < 0.01) and DPD (P < 0.05) after chemotherapy in 3 patients. In these cases, the patient assessment changed from “responder” to “non-responder”. In the non-responders, the protein expression level of TS was > 40 ng/mg protein.
CONCLUSION: We have confirmed that the protein expression level of TS is a predictive factor for the response to S-1/CDDP chemotherapy in patients with advanced gastric cancer.
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