Mingming Xiao, Rong Tang, Haoqi Pan, Jing Yang, Xuhui Tong, He Xu, Yanmei Guo, Yalan Lei, Di Wu, Yubin Lei, Yamei Han, Zhilong Ma, Wei Wang, Jin Xu, Xianjun Yu, Si Shi
{"title":"TPX2 是一个新靶点,可通过赋予合成致死率来扩大 PARPi 在胰腺癌中的应用。","authors":"Mingming Xiao, Rong Tang, Haoqi Pan, Jing Yang, Xuhui Tong, He Xu, Yanmei Guo, Yalan Lei, Di Wu, Yubin Lei, Yamei Han, Zhilong Ma, Wei Wang, Jin Xu, Xianjun Yu, Si Shi","doi":"10.1136/gutjnl-2024-332782","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>PARP inhibitors (PARPi) have been licensed for the maintenance therapy of patients with metastatic pancreatic cancer carrying pathogenic germline BRCA1/2 mutations. However, mutations in BRCA1/2 are notably rare in pancreatic cancer.</p><p><strong>Objective: </strong>There is a significant unmet clinical need to broaden the utility of PARPi.</p><p><strong>Design: </strong>RNA sequencing was performed to screen potential targets for PARPi sensitivity. The synthetic lethal effects were verified in patient-derived xenograft (PDX), xenograft and patient-derived organoid models. Mechanisms were explored via LC‒MS/MS, coimmunoprecipitation, laser microirradiation, immunofluorescence, the homologous recombination (HR) or non-homologous end joining (NHEJ) reporter system, in situ proximity ligation assay and live-cell time-lapse imaging analyses.</p><p><strong>Results: </strong>Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an exploitable vulnerability. TPX2 was downregulated in PDX models sensitive to PARPi, and TPX2 inhibition conferred synthetic lethality to PARPi both <i>in vitro</i> and <i>in vivo</i>. Mechanistically, TPX2 functions in a cell cycle-dependent manner. In the S/G2 phase, ATM-mediated TPX2 S634 phosphorylation promotes BRCA1 recruitment to double-strand breaks (DSBs) for HR repair, whereas non-phosphorylated TPX2 interacts with 53BP1 to recruit it for NHEJ. The balance between phosphorylated and non-phosphorylated TPX2 determines the DSB repair pathway choice. During mitosis, TPX2 phosphorylation enhances Aurora A activity, promoting mitotic progression and chromosomal stability. Targeting TPX2 S634 phosphorylation with a cell-penetrating peptide causes genomic instability and mitotic catastrophe and enhances PARPi sensitivity. Additionally, the inhibition of TPX2 or S634 phosphorylation combined with gemcitabine further sensitised pancreatic cancer to PARPi.</p><p><strong>Conclusions: </strong>Our findings revealed the dual-functional significance of TPX2 in controlling DNA DSB repair pathway choice and mitotic progression, suggesting a potential therapeutic strategy involving PARPi for patients with pancreatic cancer.</p>","PeriodicalId":12825,"journal":{"name":"Gut","volume":" ","pages":""},"PeriodicalIF":23.0000,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"TPX2 serves as a novel target for expanding the utility of PARPi in pancreatic cancer through conferring synthetic lethality.\",\"authors\":\"Mingming Xiao, Rong Tang, Haoqi Pan, Jing Yang, Xuhui Tong, He Xu, Yanmei Guo, Yalan Lei, Di Wu, Yubin Lei, Yamei Han, Zhilong Ma, Wei Wang, Jin Xu, Xianjun Yu, Si Shi\",\"doi\":\"10.1136/gutjnl-2024-332782\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Background: </strong>PARP inhibitors (PARPi) have been licensed for the maintenance therapy of patients with metastatic pancreatic cancer carrying pathogenic germline BRCA1/2 mutations. However, mutations in BRCA1/2 are notably rare in pancreatic cancer.</p><p><strong>Objective: </strong>There is a significant unmet clinical need to broaden the utility of PARPi.</p><p><strong>Design: </strong>RNA sequencing was performed to screen potential targets for PARPi sensitivity. The synthetic lethal effects were verified in patient-derived xenograft (PDX), xenograft and patient-derived organoid models. Mechanisms were explored via LC‒MS/MS, coimmunoprecipitation, laser microirradiation, immunofluorescence, the homologous recombination (HR) or non-homologous end joining (NHEJ) reporter system, in situ proximity ligation assay and live-cell time-lapse imaging analyses.</p><p><strong>Results: </strong>Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an exploitable vulnerability. TPX2 was downregulated in PDX models sensitive to PARPi, and TPX2 inhibition conferred synthetic lethality to PARPi both <i>in vitro</i> and <i>in vivo</i>. Mechanistically, TPX2 functions in a cell cycle-dependent manner. In the S/G2 phase, ATM-mediated TPX2 S634 phosphorylation promotes BRCA1 recruitment to double-strand breaks (DSBs) for HR repair, whereas non-phosphorylated TPX2 interacts with 53BP1 to recruit it for NHEJ. The balance between phosphorylated and non-phosphorylated TPX2 determines the DSB repair pathway choice. During mitosis, TPX2 phosphorylation enhances Aurora A activity, promoting mitotic progression and chromosomal stability. Targeting TPX2 S634 phosphorylation with a cell-penetrating peptide causes genomic instability and mitotic catastrophe and enhances PARPi sensitivity. Additionally, the inhibition of TPX2 or S634 phosphorylation combined with gemcitabine further sensitised pancreatic cancer to PARPi.</p><p><strong>Conclusions: </strong>Our findings revealed the dual-functional significance of TPX2 in controlling DNA DSB repair pathway choice and mitotic progression, suggesting a potential therapeutic strategy involving PARPi for patients with pancreatic cancer.</p>\",\"PeriodicalId\":12825,\"journal\":{\"name\":\"Gut\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":23.0000,\"publicationDate\":\"2024-11-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gut\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1136/gutjnl-2024-332782\",\"RegionNum\":1,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GASTROENTEROLOGY & HEPATOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gut","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1136/gutjnl-2024-332782","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GASTROENTEROLOGY & HEPATOLOGY","Score":null,"Total":0}
TPX2 serves as a novel target for expanding the utility of PARPi in pancreatic cancer through conferring synthetic lethality.
Background: PARP inhibitors (PARPi) have been licensed for the maintenance therapy of patients with metastatic pancreatic cancer carrying pathogenic germline BRCA1/2 mutations. However, mutations in BRCA1/2 are notably rare in pancreatic cancer.
Objective: There is a significant unmet clinical need to broaden the utility of PARPi.
Design: RNA sequencing was performed to screen potential targets for PARPi sensitivity. The synthetic lethal effects were verified in patient-derived xenograft (PDX), xenograft and patient-derived organoid models. Mechanisms were explored via LC‒MS/MS, coimmunoprecipitation, laser microirradiation, immunofluorescence, the homologous recombination (HR) or non-homologous end joining (NHEJ) reporter system, in situ proximity ligation assay and live-cell time-lapse imaging analyses.
Results: Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an exploitable vulnerability. TPX2 was downregulated in PDX models sensitive to PARPi, and TPX2 inhibition conferred synthetic lethality to PARPi both in vitro and in vivo. Mechanistically, TPX2 functions in a cell cycle-dependent manner. In the S/G2 phase, ATM-mediated TPX2 S634 phosphorylation promotes BRCA1 recruitment to double-strand breaks (DSBs) for HR repair, whereas non-phosphorylated TPX2 interacts with 53BP1 to recruit it for NHEJ. The balance between phosphorylated and non-phosphorylated TPX2 determines the DSB repair pathway choice. During mitosis, TPX2 phosphorylation enhances Aurora A activity, promoting mitotic progression and chromosomal stability. Targeting TPX2 S634 phosphorylation with a cell-penetrating peptide causes genomic instability and mitotic catastrophe and enhances PARPi sensitivity. Additionally, the inhibition of TPX2 or S634 phosphorylation combined with gemcitabine further sensitised pancreatic cancer to PARPi.
Conclusions: Our findings revealed the dual-functional significance of TPX2 in controlling DNA DSB repair pathway choice and mitotic progression, suggesting a potential therapeutic strategy involving PARPi for patients with pancreatic cancer.
期刊介绍:
Gut is a renowned international journal specializing in gastroenterology and hepatology, known for its high-quality clinical research covering the alimentary tract, liver, biliary tree, and pancreas. It offers authoritative and current coverage across all aspects of gastroenterology and hepatology, featuring articles on emerging disease mechanisms and innovative diagnostic and therapeutic approaches authored by leading experts.
As the flagship journal of BMJ's gastroenterology portfolio, Gut is accompanied by two companion journals: Frontline Gastroenterology, focusing on education and practice-oriented papers, and BMJ Open Gastroenterology for open access original research.