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Fatemi N, Karimpour M, Bahrami H, Zali MR, Chaleshi V, Riccio A, Nazemalhosseini-Mojarad E, Totonchi M. Current trends and future prospects of drug repositioning in gastrointestinal oncology. Front Pharmacol 2024; 14:1329244. [PMID: 38239190 PMCID: PMC10794567 DOI: 10.3389/fphar.2023.1329244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 12/11/2023] [Indexed: 01/22/2024] Open
Abstract
Gastrointestinal (GI) cancers comprise a significant number of cancer cases worldwide and contribute to a high percentage of cancer-related deaths. To improve survival rates of GI cancer patients, it is important to find and implement more effective therapeutic strategies with better prognoses and fewer side effects. The development of new drugs can be a lengthy and expensive process, often involving clinical trials that may fail in the early stages. One strategy to address these challenges is drug repurposing (DR). Drug repurposing is a developmental strategy that involves using existing drugs approved for other diseases and leveraging their safety and pharmacological data to explore their potential use in treating different diseases. In this paper, we outline the existing therapeutic strategies and challenges associated with GI cancers and explore DR as a promising alternative approach. We have presented an extensive review of different DR methodologies, research efforts and examples of repurposed drugs within various GI cancer types, such as colorectal, pancreatic and liver cancers. Our aim is to provide a comprehensive overview of employing the DR approach in GI cancers to inform future research endeavors and clinical trials in this field.
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Affiliation(s)
- Nayeralsadat Fatemi
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mina Karimpour
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Hoda Bahrami
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Vahid Chaleshi
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Andrea Riccio
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), Università degli Studi della Campania “Luigi Vanvitelli”, Caserta, Italy
- Institute of Genetics and Biophysics (IGB) “Adriano Buzzati-Traverso”, Consiglio Nazionale delle Ricerche (CNR), Naples, Italy
| | - Ehsan Nazemalhosseini-Mojarad
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Totonchi
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies (DiSTABiF), Università degli Studi della Campania “Luigi Vanvitelli”, Caserta, Italy
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
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Kaushik I, Ramachandran S, Prasad S, Srivastava SK. Drug rechanneling: A novel paradigm for cancer treatment. Semin Cancer Biol 2020; 68:279-290. [PMID: 32437876 DOI: 10.1016/j.semcancer.2020.03.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/15/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Cancer continues to be one of the leading contributors towards global disease burden. According to NIH, cancer incidence rate per year will increase to 23.6 million by 2030. Even though cancer continues to be a major proportion of the disease burden worldwide, it has the lowest clinical trial success rate amongst other diseases. Hence, there is an unmet need for novel, affordable and effective anti-neoplastic medications. As a result, a growing interest has sparkled amongst researchers towards drug repurposing. Drug repurposing follows the principle of polypharmacology, which states, "any drug with multiple targets or off targets can present several modes of action". Drug repurposing also known as drug rechanneling, or drug repositioning is an economic and reliable approach that identifies new disease treatment of already approved drugs. Repurposing guarantees expedited access of drugs to the patients as these drugs are already FDA approved and their safety and toxicity profile is completely established. Epidemiological studies have identified the decreased occurrence of oncological or non-oncological conditions in patients undergoing treatment with FDA approved drugs. Data from multiple experimental studies and clinical observations have depicted that several non-neoplastic drugs have potential anticancer activity. In this review, we have summarized the potential anti-cancer effects of anti-psychotic, anti-malarial, anti-viral and anti-emetic drugs with a brief overview on their mechanism and pathways in different cancer types. This review highlights promising evidences for the repurposing of drugs in oncology.
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Affiliation(s)
- Itishree Kaushik
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sharavan Ramachandran
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sahdeo Prasad
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA
| | - Sanjay K Srivastava
- Department of Immunotherapeutics and Biotechnology, and Center for Tumor Immunology and Targeted Cancer Therapy, Texas Tech University Health Sciences Center, Abilene, TX 79601, USA.
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Armando RG, Gómez DLM, Gomez DE. New drugs are not enough‑drug repositioning in oncology: An update. Int J Oncol 2020; 56:651-684. [PMID: 32124955 PMCID: PMC7010222 DOI: 10.3892/ijo.2020.4966] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/16/2019] [Indexed: 11/24/2022] Open
Abstract
Drug repositioning refers to the concept of discovering novel clinical benefits of drugs that are already known for use treating other diseases. The advantages of this are that several important drug characteristics are already established (including efficacy, pharmacokinetics, pharmacodynamics and toxicity), making the process of research for a putative drug quicker and less costly. Drug repositioning in oncology has received extensive focus. The present review summarizes the most prominent examples of drug repositioning for the treatment of cancer, taking into consideration their primary use, proposed anticancer mechanisms and current development status.
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Affiliation(s)
- Romina Gabriela Armando
- Laboratory of Molecular Oncology, Science and Technology Department, National University of Quilmes, Bernal B1876, Argentina
| | - Diego Luis Mengual Gómez
- Laboratory of Molecular Oncology, Science and Technology Department, National University of Quilmes, Bernal B1876, Argentina
| | - Daniel Eduardo Gomez
- Laboratory of Molecular Oncology, Science and Technology Department, National University of Quilmes, Bernal B1876, Argentina
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Zhao C, Wang M, Liu Y, Liang Y, Han L, Chen C. Effects of the combination of As 2O 3 and AZT on proliferation inhibition and apoptosis induction of hepatoma HepG2 cells following silencing of Egr-1. Onco Targets Ther 2018; 11:3293-3301. [PMID: 29910624 PMCID: PMC5987793 DOI: 10.2147/ott.s155169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Context Previous studies have demonstrated that 3′-azido-3′-deoxythymidine (AZT) and arsenic trioxide (As2O3), traditional chemotherapy agents, can synergically inhibit the growth of hepatocellular carcinoma cells. However, the molecular mechanisms underlying As2O3 and AZT anti-hepatoma activity are unknown. Objective This study aimed to investigate the role of early growth response protein 1 (Egr-1) in the process of As2O3 combined with AZT inhibiting proliferation and inducing apoptosis of human hepatocellular carcinoma HepG2 cells, and explore the possible mechanism. Materials and methods The expression of Egr-1 was silenced using siRNA, and then HepG2 cells were treated with As2O3 (2 μM) and AZT (20 μM). The rates of cell inhibition and apoptosis were determined by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) method and flow cytometry, respectively. The mRNA and protein expression of p53, caspase-3, and Egr-1 were detected by real-time quantitative polymerase chain reaction and Western blotting, respectively. Results The inhibitory rate of As2O3 (2 μM) combined with AZT (20 μM) on proliferation of HepG2 cells was significantly higher than that of As2O3 alone. The combination index (CI) values were 0.2<CI<0.4, showing strong synergic effect. After silencing Egr-1, the proliferation inhibition and proapoptotic ability of As2O3 combined with AZT on HepG2 cells were decreased, and the CI value was greater than 1, showing antagonistic effect. In addition, the expression of p53 and caspase-3 mRNA/protein was also significantly decreased. Conclusion The present results show that AZT could increase the sensitization of As2O3 for inhibiting proliferation and promoting apoptosis of HepG2 cells through regulating the expression of Egr-1, which may control the expression of p53 and caspase-3.
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Affiliation(s)
- Chuan Zhao
- Department of Clinical Laboratory Diagnostics and Molecular Biology, Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou, Gansu, China
| | - Mei Wang
- Department of Clinical Laboratory Diagnostics and Molecular Biology, Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou, Gansu, China
| | - Yu Liu
- Department of Clinical Laboratory Diagnostics and Molecular Biology, Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou, Gansu, China
| | - Yongjuan Liang
- Department of Clinical Laboratory Diagnostics and Molecular Biology, Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou, Gansu, China
| | - Li Han
- Emergency Research Institution, Lanzhou University Second Hospital, Lanzhou, Gansu, China
| | - Che Chen
- Department of Clinical Laboratory Diagnostics and Molecular Biology, Clinical Medical College, Gansu University of Chinese Medicine, Lanzhou, Gansu, China
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Wang H, Zhou J, He Q, Dong Y, Liu Y. Azidothymidine inhibits cell growth and telomerase activity and induces DNA damage in human esophageal cancer. Mol Med Rep 2017; 15:4055-4060. [PMID: 28487971 PMCID: PMC5436214 DOI: 10.3892/mmr.2017.6549] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 02/27/2017] [Indexed: 12/26/2022] Open
Abstract
Esophageal cancer is one of the most common type of malignancies. Telomerase activity, which is absent or weakly detected in the majority of human somatic cells, is elevated in esophageal cancer. Although azidothymidine (AZT), a reverse transcriptase inhibitor, has been utilized as a treatment for tumors, its role in treating esophageal cancer has not been confirmed. The aim of the present study was to determine the effect of AZT on telomerase activity and the proliferation of the human esophageal cancer cell line TE-11. A telomeric repeat amplification assay was utilized to detect telomerase activity following treatment of TE-11 cells with AZT. The effect of AZT on TE-11 cell cycle distribution was determined by flow cytometry. Cellular DNA damage was evaluated by a comet assay and an MTT assay demonstrated that AZT significantly inhibited the viability of TE-11 cells, in a time-and dose-dependent manner. In addition, TE-11 cells treated with various concentrations of AZT exhibited a significant reduction in telomerase activity and percentage of cells in the G1/G0 phase, and an increase in the percentage of cells in the S phase. High doses of AZT caused DNA damage, and enhanced the expression levels of γ-H2A histone family member X and phosphorylated checkpoint kinase 2 in TE-11 cells. These results demonstrated that AZT effectively inhibits proliferation of the TE-11 human esophageal cancer cell line in vitro. The growth inhibitory effects were associated with a reduction in telomerase activity, S and G2/M phase cell cycle arrest, and enhanced DNA damage, suggesting that AZT may be utilized in the clinic for the treatment of esophageal cancer.
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Affiliation(s)
- Haoli Wang
- Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong 510080, P.R. China
| | - Jianwen Zhou
- Department of Pathology, First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Qiong He
- Department of Pathology, First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yu Dong
- Department of Pathology, First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yanhui Liu
- Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong 510080, P.R. China
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Gomez DLM, Armando RG, Cerrudo CS, Ghiringhelli PD, Gomez DE. Telomerase as a Cancer Target. Development of New Molecules. Curr Top Med Chem 2017; 16:2432-40. [PMID: 26873194 PMCID: PMC4997958 DOI: 10.2174/1568026616666160212122425] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 09/15/2015] [Accepted: 10/25/2015] [Indexed: 12/26/2022]
Abstract
Telomeres are the terminal part of the chromosome containing a long repetitive and non-codifying sequence that has as function protecting the chromosomes. In normal cells, telomeres lost part of such repetitive sequence in each mitosis, until telomeres reach a critical point, triggering at that time senescence and cell death. However, in most of tumor cells in each cell division a part of the telomere is lost, however the appearance of an enzyme called telomerase synthetize the segment that just has been lost, therefore conferring to tumor cells the immortality hallmark. Telomerase is significantly overexpressed in 80–95% of all malignant tumors, being present at low levels in few normal cells, mostly stem cells. Due to these characteristics, telomerase has become an attractive target for new and more effective anticancer agents. The capability of inhibiting telomerase in tumor cells should lead to telomere shortening, senescence and apoptosis. In this work, we analyze the different strategies for telomerase inhibition, either in development, preclinical or clinical stages taking into account their strong points and their caveats. We covered strategies such as nucleosides analogs, oligonucleotides, small molecule inhibitors, G-quadruplex stabilizers, immunotherapy, gene therapy, molecules that affect the telomere/telomerase associated proteins, agents from microbial sources, among others, providing a balanced evaluation of the status of the inhibitors of this powerful target together with an analysis of the challenges ahead.
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Affiliation(s)
| | | | | | | | - D E Gomez
- Laboratory of Molecular Oncology, Department of Science and Technology. Quilmes National University, Bernal, Buenos Aires, Argentina. R. Saenz Peña 352, (1876) Buenos Aires, Argentina.
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Gomez DE, Armando RG, Alonso DF. AZT as a telomerase inhibitor. Front Oncol 2012; 2:113. [PMID: 22973556 PMCID: PMC3434370 DOI: 10.3389/fonc.2012.00113] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 08/17/2012] [Indexed: 01/23/2023] Open
Abstract
Telomerase is a highly specialized reverse transcriptase (RT) and the maintenance of telomeric length is determined by this specific enzyme. The human holoenzyme telomerase is a ribonucleoprotein composed by a catalytic subunit, hTERT, an RNA component, hTR, and a group of associated proteins. Telomerase is normally expressed in embryonic cells and is repressed during adulthood. The enzyme is reexpressed in around 85% of solid tumors. This observation makes it a potential target for developing drugs that could be developed for therapeutic purposes. The identification of the hTERT as a functional catalytic RT prompted studies of inhibiting telomerase with the HIV RT inhibitor azidothymidine (AZT). Previously, we have demonstrated that AZT binds preferentially to telomeres, inhibits telomerase and enhances tumor cell senescence, and apoptosis after AZT treatment in breast mammary adenocarcinoma cells. Since then, several studies have considered AZT for telomerase inhibition and have led to potential clinical strategies for anticancer therapy. This review covers present thinking of the inhibition of telomerase by AZT and future treatment protocols using the drug.
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Affiliation(s)
- Daniel E Gomez
- Laboratory of Molecular Oncology, Department of Science and Technology, Quilmes National University, Bernal Buenos Aires, Argentina
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Azidothymidine enhances fluorodeoxyuridine-mediated radiosensitization. Int J Radiat Oncol Biol Phys 2010; 76:905-13. [PMID: 20159365 DOI: 10.1016/j.ijrobp.2009.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 09/11/2009] [Accepted: 09/14/2009] [Indexed: 11/24/2022]
Abstract
PURPOSE To examine the role of DNA repair and altered thymidine analogues in altering the response to radiation during thymidine deprivation. METHODS AND MATERIALS Mismatch repair-deficient and -proficient cell lines HEC59 and HC-2.4 were treated with fluorodeoxyuridine (FUdR), azidothymidine (AZT), and irradiation either alone or in combination, and outcomes of clonogenic survival and cell-cycle distributions were determined. RESULTS Survival outcomes for all treatments were similar for both cell lines, suggesting that hMSH2 does not significantly influence thymidine deprivation toxicity or radiosensitization. The chain-terminating thymidine analogue AZT increased the toxicity of FUdR and increased DNA fragmentation. The combination of FUdR and AZT afforded greater radiosensitization than either drug alone. Drug enhancement ratios, the degree of excess radiation-induced cell death in drug-treated cultures compared with radiation alone for HEC59, were 1.2, 1.4, and 1.8 for AZT, FUdR, and the combination, respectively. Enhancement ratios for HC-2.4 were 1.3, 1.5, and 1.8 for AZT, FUdR, and the combination, respectively. CONCLUSION Azidothymidine, a chain-terminating thymidine analogue, can enhance the radiosensitizing affects of thymidine deprivation. Deoxyribonucleic acid strand breaks may play an important role in the mechanism of thymidine deprivation-induced radiosensitization.
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Fang JL, Beland FA. Long-term exposure to zidovudine delays cell cycle progression, induces apoptosis, and decreases telomerase activity in human hepatocytes. Toxicol Sci 2009; 111:120-30. [PMID: 19541796 DOI: 10.1093/toxsci/kfp136] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Zidovudine (3'-azido-3'-deoxythymidine; AZT), which is currently used in the treatment of acquired immunodeficiency syndrome, has been shown to have anticancer properties. In the present study, we examined the mechanisms contributing to increased sensitivity of cancer cells to the growth-inhibitory effects of AZT. This was accomplished by incubating a hepatoma cell line (HepG2) and a normal liver cell line (THLE2) with AZT in continuous culture for up to 4 weeks and evaluating the number of viable and necrotic cells, the induction of apoptosis, cell cycle alterations, and telomerase activity. In HepG2 cells, AZT (2-100 microM) caused significant dose-dependent decreases in the number of viable cells at exposures > 24 h. During a 1-week recover period, there was only a slight increase in the number of viable cells treated with AZT. The decrease in viable cells was associated with an induction of apoptosis, a decrease in telomerase activity, and S and G2/M phase arrest of the cell cycle. During the recovery period, the extent of apoptosis and telomerase activity returned to control levels, whereas the disruption of cell cycle progression persisted. Western blot analysis indicated that AZT caused a decrease in checkpoint kinase 1 (Chk1) and kinase 2 (Chk2) and an increase in phosphorylated Chk1 (Ser345) and Chk2 (Thr68). Similar effects, to lesser extent, were observed in THLE2 cells given much higher concentrations of AZT (50-2500 microM). These data show that HepG2 cells are much more sensitive than THLE2 cells to AZT. They also indicate that a combination of a delay of cell cycle progression, an induction of apoptosis, and a decrease in telomerase activity is contributing to the decrease in the number of viable cells from AZT treatment, and that checkpoint enzymes Chk1 and Chk2 may play an important role in the delay of cell cycle progression.
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Affiliation(s)
- Jia-Long Fang
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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Wu D, Ji S, Wu Y, Ju Y, Zhao Y. Design, synthesis, and antitumor activity of bile acid–polyamine–nucleoside conjugates. Bioorg Med Chem Lett 2007; 17:2983-6. [PMID: 17416522 DOI: 10.1016/j.bmcl.2007.03.067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 03/19/2007] [Accepted: 03/22/2007] [Indexed: 10/23/2022]
Abstract
A series of bile acid-polyamine amides conjugated with 3'-azido-3'-deoxythymidine (AZT) as potential antitumor prodrugs in the form of phosphoramidates were synthesized in good yields and their antitumor activities were assayed against two human cancer cells in vitro: cervix cancer HeLa cells and renal cancer 7860 cells. The improved antitumor activity probably derived from the enhanced delivery efficiency of AZT due to bile acid-polyamine conjugates.
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Affiliation(s)
- Dimao Wu
- Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, PR China
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Tsuneyoshi K, Haraguchi M, Hongye Z, Gotanda T, Tachiwada T, Sumizawa T, Furukawa T, Baba M, Akiyama SI, Nakagawa M. Induction of thymidine phosphorylase expression by AZT contributes to enhancement of 5'-DFUR cytotoxicity. Cancer Lett 2006; 244:239-46. [PMID: 16457948 DOI: 10.1016/j.canlet.2005.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 08/10/2005] [Accepted: 12/10/2005] [Indexed: 11/29/2022]
Abstract
Thymidine phosphorylase (TP) regulates intracellular thymidine metabolism and can enhance the anti-tumor effectiveness of 5'-deoxy-5-fluorouridine (5'-DFUR) by conversion of the pro-drug 5'-DFUR to 5-fluorouracil (5-FU) in tumor tissues. 5'-DFUR is an effective anti-tumor drug in cells expressing high levels of TP. 3'-Azido 3'-deoxythymidine (AZT) is a thymidine analog that has been proven useful in the treatment of acquired immunodefiency syndrome (AIDS). In this study, we found that AZT induces TP expression and enhances the sensitivity of human myeloid leukemia U937 cells to 5'-DFUR. Both the protein level and the activity of TP in U937 cells were elevated for 48h after exposure to AZT (20, 100 or 300muM). AZT enhanced TP promoter activity in a dose-dependent manner. AZT also increased TP mRNA levels in U937 cells as assayed by Real-time reverse-transcription PCR. AZT enhanced the cytotoxic effect of 5'-DFUR on U937 cells. A TP inhibitor, TPI, abrogated the cytotoxic activity of 5'-DFUR, and attenuated the combined cytotoxicity of AZT and 5'-DFUR. These results suggest that AZT enhances the cytotoxic effect of 5'-DFUR on U937 cells by upregulating TP activity in addition to its inhibition of thymidine kinase (TK) activity and reduction of intracellular dTTP pools.
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Affiliation(s)
- Kengo Tsuneyoshi
- Department of Molecular Oncology, Field of Oncology, Course of Advanced Therapeutics, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima 890-8520, Japan
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Macchi B, Mastino A. Pharmacological and biological aspects of basic research on nucleoside-based reverse transcriptase inhibitors. Pharmacol Res 2002; 46:473-82. [PMID: 12457619 DOI: 10.1016/s1043661802002128] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Antiretrovirals have progressively entered clinical practice since the discovery of the association between the acquired immunodeficiency syndrome (AIDS) and human immunodeficiency virus (HIV) infection. Among the classes of drugs which have shown efficacy against HIV, nucleoside-based reverse transcriptase inhibitors (NRTIs) have been extensively investigated in both their basic and therapeutic aspects. The basic mechanism of the effects of NRTIs relies on interaction with both viral and host cell functions. This implies that NRTIs could act not only by inhibiting viral genome replication, but also by interfering with some basic mechanism regulating cell growth and death. According to these characteristics, NRTIs might share several similarities with antineoplastic agents, including side effects. In this article, we have briefly reviewed the pharmacological activities of NRTIs in viral replication, neoplastic growth and cellular functions. These aspects might be involved both in the beneficial and adverse effects of NRTIs.
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Affiliation(s)
- B Macchi
- Department of Neuroscience, University of Rome Tor Vergata, Via Montpellier, 00133 Rome, Italy
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Tejera AM, Alonso DF, Gomez DE, Olivero OA. Chronic in vitro exposure to 3'-azido-2', 3'-dideoxythymidine induces senescence and apoptosis and reduces tumorigenicity of metastatic mouse mammary tumor cells. Breast Cancer Res Treat 2001; 65:93-9. [PMID: 11261835 DOI: 10.1023/a:1006477730934] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Normal cells in culture divide a certain amount of times and undergo a process termed replicative senescence. Telomere loss is thought to control entry into senescence. Activation of telomerase in tumors bypasses cellular senescence and is thus a requirement for tumor progression. We reported previously the preferential incorporation of 3'-azido-2', 3'-dideoxythymidine (AZT) in telomeric sequences of immortalized cells in culture. In this work, we have investigated the effects of chronic in vitro AZT exposure on F3II mouse mammary carcinoma cells. We demonstrate, for the first time, that AZT-treated tumor cells have a reduced tumorigenicity in syngeneic BALB/c mice. Tumor incidence was reduced and survival was prolonged in animals inoculated with AZT-treated cells when comparing with control counterparts. The number and size of spontaneous metastases were also decreased in animals inoculated with AZT-treated cells. In addition, we present evidence of morphological and biochemical signs of senescence, as shown by the staining for senescence associated beta-galactosidase activity, and induction of programmed cell death, as demonstrated by an increase of caspase-3 activity, in tumor cells exposed to AZT. These data indicate that chronic exposure of mammary carcinoma cells to AZT may be sufficient to induce a senescent phenotype and to reduce tumorigenicity.
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Affiliation(s)
- A M Tejera
- Laboratory of Molecular Oncology Quilmes National University, Buenos Aires, Argentina
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