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Tao L, Xia X, Kong S, Wang T, Fan F, Wang W. Natural pentacyclic triterpenoid from Pristimerin sensitizes p53-deficient tumor to PARP inhibitor by ubiquitination of Chk1. Pharmacol Res 2024; 201:107091. [PMID: 38316371 DOI: 10.1016/j.phrs.2024.107091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 02/07/2024]
Abstract
Inhibition of checkpoint kinase 1 (Chk1) has shown to overcome resistance to poly (ADP-ribose) polymerase (PARP) inhibitors and expand the clinical utility of PARP inhibitors in a broad range of human cancers. Pristimerin, a naturally occurring pentacyclic triterpenoid, has been the focus of intensive studies for its anticancer potential. However, it is not yet known whether low dose of pristimerin can be combined with PARP inhibitors by targeting Chk1 signaling pathway. In this study, we investigated the efficacy, safety and molecular mechanisms of the synergistic effect produced by the combination olaparib and pristimerin in TP53-deficient and BRCA-proficient cell models. As a result, an increased expression of Chk1 was correlated with TP53 mutation, and pristimerin preferentially sensitized p53-defective cells to olaparib. The combination of olaparib and pristimerin resulted in a more pronounced abrogation of DNA synthesis and induction of DNA double-strand breaks (DSBs). Moreover, pristimerin disrupted the constitutional levels of Chk1 and DSB repair activities. Mechanistically, pristimerin promoted K48-linked polyubiquitination and proteasomal degradation of Chk1 while not affecting its kinase domain and activity. Importantly, combinatorial therapy led to a higher rate of tumor growth inhibition without apparent hematological toxicities. In addition, pristimerin suppressed olaparib-induced upregulation of Chk1 and enhanced olaparib-induced DSB marker γΗ2ΑΧ in vivo. Taken together, inhibition of Chk1 by pristimerin has been observed to induce DNA repair deficiency, which may expand the application of olaparib in BRCA-proficient cancers harboring TP53 mutations. Thus, pristimerin can be combined for PARP inhibitor-based therapy.
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Affiliation(s)
- Li Tao
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu 225009, China.
| | - Xiangyu Xia
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Shujing Kong
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Tingye Wang
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Fangtian Fan
- Anhui Engineering Technology Research Center of Biochemical Pharmaceuticals, School of Pharmacy, Bengbu Medical College, Bengbu, Anhui 233003, China
| | - Weimin Wang
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu 225009, China; Department of Oncology, Yixing Hospital Affiliated to Medical College of Yangzhou University, Yixing, Jiangsu 214200, China.
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Tao L, Zhou K, Zhao Y, Xia X, Guo Y, Gao Y, Peng G, Liu Y. Betulinic acid, a major therapeutic triterpene of Celastrus orbiculatus Thunb., acts as a chemosensitizer of gemcitabine by promoting Chk1 degradation. JOURNAL OF ETHNOPHARMACOLOGY 2023; 309:116295. [PMID: 36813244 DOI: 10.1016/j.jep.2023.116295] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/01/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Celastrus orbiculatus Thunb., also called as oriental bittersweet vine or climbing spindle berry, a traditional Chinese herbal medicine has been used to treat a spectrum of painful and inflammatory diseases for centuries. Explored for their unique medicinal properties, C.orbiculatus offers additional therapeutic effects on cancerous diseases. The effect of single-agent gemcitabine on survival has not long been encouraging, combination therapies provide patients multiple chances of benefit for improved clinical response. AIMS OF THIS STUDY This study aims at expounding the chemopotentiating effects and underlying mechanisms of betulinic acid, a primary therapeutic triterpene of C. orbiculatus in combination with gemcitabine chemotherapy. MATERIALS AND METHODS The preparation of betulinic acid was optimized using ultrasonic-assisted extraction method. Gemcitabine-resistant cell model was established by induction of the cytidine deaminase. MTT, colony formation, EdU incorporation and Annexin V/PI staining assays were used to evaluate cytotoxicity, cell proliferation and apoptosis in BxPC-3 pancreatic cancer cell line and H1299 non-small cell lung carcinoma cell line. Comet assay, metaphase chromosome spread and γH2AX immunostaining were applied for DNA damage assessment. Western blot and co-immunoprecipitation was used to detect the phosphorylation and ubiquitination of Chk1. Mode of action of gemcitabine in combination with betulinic acid was further captured in BxPC-3-derived mouse xenograft model. RESULTS We noticed that the extraction method had an impact on the thermal stability of C. orbiculatus. Ultrasound-assisted extraction at room temperature in shorter processing time could maximize the overall yields and biological activities of C. orbiculatus. The major constituent was identified as betulinic acid, and the pentacyclic triterpene represented the prominent anticancer activity of C. orbiculatus. Forced expression of cytidine deaminase conferred acquired resistance to gemcitabine, while betulinic acid displayed equivalent cytotoxicity toward gemcitabine-resistant and sensitive cells. A combination therapy of gemcitabine with betulinic acid produced synergistic pharmacologic interaction on cell viability, apoptosis and DNA double-strand breaks. Moreover, betulinic acid abrogated gemcitabine-triggered Chk1 activation by destabilizing Chk1 loading via proteasomal degradation. The combination of gemcitabine and betulinic acid significantly retarded BxPC-3 tumor growth in vivo compared to single-agent gemcitabine treatment alone, accompanied with reduced Chk1 expression. CONCLUSIONS These data provide evidence that betulinic acid is a potential candidate for chemosensitization as a naturally occurring Chk1 inhibitor and warrants further preclinical evaluation.
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Affiliation(s)
- Li Tao
- Department of Pharmacy, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China; The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
| | - Kehui Zhou
- Department of Pharmacy, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China; The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yang Zhao
- Department of Pharmacy, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China; The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China; Department of Medicine, Linfen Vocational and Technical College, Linfen, Shanxi, 041000, China
| | - Xiangyu Xia
- Department of Pharmacy, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China; The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yajie Guo
- Department of Pharmacy, School of Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China; The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Yang Gao
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210046, China
| | - Guoping Peng
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210046, China.
| | - Yanqing Liu
- The State Administration of Traditional Chinese Medicine Key Laboratory of Toxic Pathogens-Based Therapeutic Approaches of Gastric Cancer, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
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