Quinacrine Induces Nucleolar Stress in Treatment-Refractory Ovarian Cancer Cell Lines

A considerable subset of gynecologic cancer patients experience disease recurrence or acquired resistance, which contributes to high mortality rates in ovarian cancer (OC). Our prior studies showed that quinacrine (QC), an antimalarial drug, enhanced chemotherapy sensitivity in treatment-refractory OC cells, including artificially generated chemoresistant and high-grade serous OC cells. In this study, we investigated QC-induced transcriptomic changes to uncover its cytotoxic mechanisms of action. Isogenic pairs of OC cells generated to be chemoresistant and their chemosensitive counterparts were treated with QC followed by RNA-seq analysis. Validation of selected expression results and database comparison analyses indicated the ribosomal biogenesis (RBG) pathway is inhibited by QC. RBG is commonly upregulated in cancer cells and is emerging as a drug target. We found that QC attenuates the in vitro and in vivo expression of nucleostemin (NS/GNL3), a nucleolar RBG and DNA repair protein, and the RPA194 catalytic subunit of Pol I that results in RBG inhibition and nucleolar stress. QC promotes the redistribution of fibrillarin in the form of extranuclear foci and nucleolar caps, an indicator of nucleolar stress conditions. In addition, we found that QC-induced downregulation of NS disrupted homologous recombination repair both by reducing NS protein levels and PARylation resulting in reduced RAD51 recruitment to DNA damage. Our data suggest that QC inhibits RBG and this inhibition promotes DNA damage by directly downregulating the NS–RAD51 interaction. Additionally, QC showed strong synergy with PARP inhibitors in OC cells. Overall, we found that QC downregulates the RBG pathway, induces nucleolar stress, supports the increase of DNA damage, and sensitizes cells to PARP inhibition, which supports new therapeutic stratagems for treatment-refractory OC. Our work offers support for targeting RBG in OC and determines NS to be a novel target for QC.

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Emerging Roles for Ion Channels in Ovarian Cancer: Pathomechanisms and Pharmacological Treatment

Cancers ◽

10.3390/cancers13040668 ◽

2021 ◽

Vol 13 (4) ◽

pp. 668

Author(s):

Concetta Altamura ◽

Maria Raffaella Greco ◽

Maria Rosaria Carratù ◽

Rosa Angela Cardone ◽

Jean-François Desaphy

Keyword(s):

Ovarian Cancer ◽

Ion Channels ◽

Transient Receptor Potential ◽

Critical Role ◽

Gynecologic Cancer ◽

Receptor Potential ◽

Transient Receptor Potential Channels ◽

Platinum Resistance

Ovarian cancer (OC) is the deadliest gynecologic cancer, due to late diagnosis, development of platinum resistance, and inadequate alternative therapy. It has been demonstrated that membrane ion channels play important roles in cancer processes, including cell proliferation, apoptosis, motility, and invasion. Here, we review the contribution of ion channels in the development and progression of OC, evaluating their potential in clinical management. Increased expression of voltage-gated and epithelial sodium channels has been detected in OC cells and tissues and shown to be involved in cancer proliferation and invasion. Potassium and calcium channels have been found to play a critical role in the control of cell cycle and in the resistance to apoptosis, promoting tumor growth and recurrence. Overexpression of chloride and transient receptor potential channels was found both in vitro and in vivo, supporting their contribution to OC. Furthermore, ion channels have been shown to influence the sensitivity of OC cells to neoplastic drugs, suggesting a critical role in chemotherapy resistance. The study of ion channels expression and function in OC can improve our understanding of pathophysiology and pave the way for identifying ion channels as potential targets for tumor diagnosis and treatment.

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Effect of therapeutic GAS6/AXL inhibition of tumor and stromal cells on DNA damage and response to chemotherapy in ovarian cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.e14676 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. e14676-e14676 ◽

Cited By ~ 2

Author(s):

Mary M Mullen ◽

Elena Lomonosova ◽

Hollie M Noia ◽

Lei Guo ◽

Lindsay Midori Kuroki ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Neoadjuvant Chemotherapy ◽

Cell Viability ◽

Mouse Models ◽

Stromal Cells ◽

Predictive Biomarker ◽

Response To Chemotherapy

e14676 Background: Ovarian cancer is the leading cause of death due to gynecologic malignancy. Biomarkers to predict chemoresponse and novel therapies to target these proteins would be practice changing. We aim to establish serum and tissue GAS6 as a predictive biomarker of chemoresponse and to determine if AXL inhibition through sequestration of its ligand, GAS6, with AVB-S6-500 (AVB) can improve chemoresponse. Methods: AVB was supplied by Aravive Biologics. High grade serous ovarian cancer (HGSOC) tumor samples were obtained pre- and post-neoadjuvant chemotherapy. AXL and GAS6 expression were evaluated by immunohistochemistry and serum concentration. In vitro viability and clonogenic assays were performed on chemoresistant tumor (OVCAR8, OVCAR5, COV62, and POV71-hTERT) and stromal cells (CAF86) treated with chemotherapy +/- AVB. Mouse models (OVCAR8, PDX, OVCAR5) were used to determine if the combination of chemotherapy + AVB reduced tumor burden. Immunofluorescent assays targeting ɣH2AX were used to evaluate DNA damage. Results: Patients with high pretreatment tumor GAS6 expression ( > 85%, n = 7) or serum GAS6 concentrations ( > 25ng/mL, n = 13) were more likely to be resistant to neoadjuvant chemotherapy than those with low tumor GAS6 expression ( < 45%, n = 4) (P = 0.010) or low serum GAS6 concentrations ( < 15ng/mL, n = 5) (P = 0.002). Carboplatin plus AVB (2µM, 5µM) and paclitaxel plus AVB (1µM) resulted in decreased cell viability and clonogenic growth compared to chemotherapy alone (p < 0.05) in all tumor and stromal cell lines. Synergism was seen between carboplatin+AVB and paclitaxel+AVB with a weighted combination index < 1. In vivo tumor mouse models treated with chemotherapy+AVB had significantly smaller subcutaneous and intraperitoneal (IP) tumors than those treated with chemotherapy alone (3.1mg vs 64mg, P = 0.003 OVCAR8; 62mg vs 157mg, P = 0.0108 PDX subcutaneous model; 0.05mg vs 0.3669mg, P < 0.001 OVCAR5 IP model). Increased DNA damage was noted in tumor and stromal cells treated with carboplatin+AVB compared to carboplatin alone (OVCAR8, COV362, CAF86 P < 0.001). Conclusions: High GAS6 is associated with lack of neoadjuvant chemoresponse in HGSOC patients. The combination of chemotherapy with AVB decreases tumor cell viability, tumor growth, and an increase in DNA damage response.

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CYT-Rx20 inhibits ovarian cancer cells in vitro and in vivo through oxidative stress-induced DNA damage and cell apoptosis

Cancer Chemotherapy and Pharmacology ◽

10.1007/s00280-017-3330-9 ◽

2017 ◽

Vol 79 (6) ◽

pp. 1129-1140 ◽

Cited By ~ 4

Author(s):

Yen-Yun Wang ◽

Yuk-Kwan Chen ◽

Stephen Chu-Sung Hu ◽

Ya-Ling Hsu ◽

Chun-Hao Tsai ◽

...

Keyword(s):

Oxidative Stress ◽

Ovarian Cancer ◽

Dna Damage ◽

Cancer Cells ◽

Cell Apoptosis ◽

Ovarian Cancer Cells

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Efficacy of a Covalent Microtubule Stabilizer in Taxane-Resistant Ovarian Cancer Models

Molecules ◽

10.3390/molecules26134077 ◽

2021 ◽

Vol 26 (13) ◽

pp. 4077

Author(s):

Samantha S. Yee ◽

April L. Risinger

Keyword(s):

Ovarian Cancer ◽

Acquired Resistance ◽

Disease Model ◽

Intraperitoneal Administration ◽

Metastatic Progression ◽

Clinical Prognosis ◽

Microtubule Stabilization ◽

Cancer Models

Ovarian cancer often has a poor clinical prognosis because of late detection, frequently after metastatic progression, as well as acquired resistance to taxane-based therapy. Herein, we evaluate a novel class of covalent microtubule stabilizers, the C-22,23-epoxytaccalonolides, for their efficacy against taxane-resistant ovarian cancer models in vitro and in vivo. Taccalonolide AF, which covalently binds β-tubulin through its C-22,23-epoxide moiety, demonstrates efficacy against taxane-resistant models and shows superior persistence in clonogenic assays after drug washout due to irreversible target engagement. In vivo, intraperitoneal administration of taccalonolide AF demonstrated efficacy against the taxane-resistant NCI/ADR-RES ovarian cancer model both as a flank xenograft, as well as in a disseminated orthotopic disease model representing localized metastasis. Taccalonolide-treated animals had a significant decrease in micrometastasis of NCI/ADR-RES cells to the spleen, as detected by quantitative RT-PCR, without any evidence of systemic toxicity. Together, these findings demonstrate that taccalonolide AF retains efficacy in taxane-resistant ovarian cancer models in vitro and in vivo and that its irreversible mechanism of microtubule stabilization has the unique potential for intraperitoneal treatment of locally disseminated taxane-resistant disease, which represents a significant unmet clinical need in the treatment of ovarian cancer patients.

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Ubiquitination-mediated degradation of TRDMT1 regulates homologous recombination and therapeutic response

NAR Cancer ◽

10.1093/narcan/zcab010 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Xiaolan Zhu ◽

Xiangyu Wang ◽

Wei Yan ◽

Haibo Yang ◽

Yufei Xiang ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Homologous Recombination ◽

Tumor Cells ◽

Therapeutic Response ◽

3D Structure ◽

Platinum Resistance ◽

Promising Therapeutic Target

Abstract The RNA methyltransferase TRDMT1 has recently emerged as a key regulator of homologous recombination (HR) in the transcribed regions of the genome, but how it is regulated and its relevance in cancer remain unknown. Here, we identified that TRDMT1 is poly-ubiquitinated at K251 by the E3 ligase TRIM28, removing TRDMT1 from DNA damage sites and allowing completion of HR. Interestingly, K251 is adjacent to G155 in the 3D structure, and the G155V mutation leads to hyper ubiquitination of TRDMT1, reduced TRDMT1 levels and impaired HR. Accordingly, a TRDMT1 G155V mutation in an ovarian cancer super responder to platinum treatment. Cells expressing TRDMT1-G155V are sensitive to cisplatin in vitro and in vivo. In contrast, high expression of TRDMT1 in patients with ovarian cancer correlates with platinum resistance. A potent TRDMT1 inhibitor resensitizes TRDMT1-high tumor cells to cisplatin. These results suggest that TRDMT1 is a promising therapeutic target to sensitize ovarian tumors to platinum therapy.

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Targeting dormant ovarian cancer cells in vitro and in an in vivo model of platinum resistance

10.1101/716464 ◽

2019 ◽

Cited By ~ 1

Author(s):

Zhiqing Huang ◽

Eiji Kondoh ◽

Zachary Visco ◽

Tsukasa Baba ◽

Noriomi Matsumura ◽

...

Keyword(s):

Gene Expression ◽

Ovarian Cancer ◽

Cancer Cells ◽

Cell Lines ◽

Disease Recurrence ◽

Mitochondrial Pathway ◽

Ovarian Cancer Cells ◽

Serum Free

ABSTRACTObjectiveOvarian cancer cells often exist in vivo as multicellular spheroids. Spheroid formation in vitro has been used to enrich for cancer stem cell populations from primary tumors. Such spheroids exhibit drug resistance and slow proliferation, suggesting involvement in disease recurrence. Our objectives were to characterize cancer spheroid phenotypes, determine gene expression profiles associated with spheroid forming capacity and to evaluate the responsiveness of spheroids to commonly used and novel therapeutic agents.MethodsTumorigenic potential was assessed using anchorage independent growth assays in 24 cell lines. Spheroids from cell lines (N=12) and from primary cancers (N=8) were grown on non-adherent tissue culture plates in serum-free media. Cell proliferation was measured using MTT assays and Ki67 immunostaining. Affymetrix HT U133A gene expression data was used to identify differentially expressed genes based on spheroid forming capacity. Matched monolayers and spheroids (N=7 pairs) were tested for response to cisplatin, paclitaxel and 7-hydroxystaurosporine (UCN-01) while mitochondrial inhibition was performed using oligomycin. Xenograft tumors from intraperitoneal injection of CAOV2-GFP/LUC ovarian cancer cells into nude mice were treated with carboplatin to reduce tumor burden followed by secondary treatment with carboplatin, UCN-01, or Oltipraz. Tumor formation and response was monitored using live imaging.ResultsOf 12 cell lines with increased anchorage-independent growth, 8 also formed spheroids under serum-free spheroid culture conditions. Spheroids showed reduced proliferation (p<0.0001) and Ki67 immunostaining (8% versus 87%) relative to monolayer cells. Spheroid forming capacity was associated with increased mitochondrial pathway activity (p ≤ 0.001). The mitochondrial inhibitors, UCN-01 and Oligomycin, demonstrated effectiveness against spheroids, while spheroids were refractory to cisplatin and paclitaxel. By live in vivo imaging, ovarian cancer xenograft tumors were reduced after primary treatment with carboplatin. Continued treatment with carboplatin was accompanied by an increase in tumor signal while there was little or no increase in tumor signal observed with subsequent treatment with UCN-01 or Oltipraz.ConclusionsOur findings suggest that the mitochondrial pathway in spheroids may be an important therapeutic target in preventing disease recurrence.

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CircCRIM1 promotes ovarian cancer progression by working as ceRNAs of CRIM1 and targeting miR-383-5p/ZEB2 axis

Reproductive Biology and Endocrinology ◽

10.1186/s12958-021-00857-3 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Yuping Du ◽

Xin Liu ◽

Song Zhang ◽

Shuo Chen ◽

Xue Guan ◽

...

Keyword(s):

Ovarian Cancer ◽

Cancer Progression ◽

Gynecologic Cancer ◽

Luciferase Assay ◽

Luciferase Reporter ◽

Circular Rnas ◽

Reporter System ◽

Correlation Relationship

Abstract Background Ovarian cancer is the leading cause of death in patients with gynecologic cancer, and circular RNAs (circRNAs) are involved in cancer progression. However, there are limited studies on the roles of circRNAs in ovarian cancer. Methods We designed divergent and convergent primers, used sanger sequencing and RNase R digestion to verify the source of circCRIM1. We detected the expression of circCRIM1 and its parental gene cysteine rich transmembrane BMP regulator 1 (CRIM1) in ovarian cancer and normal ovarian samples via qRT-PCR. MTT viability assay, apoptosis assay, wound healing assay and invasion assay were used to investigate the function of circCRIM1 and CRIM1 in ovarian cancer cell lines OVCAR3 and CAOV3. Mice xenografts experiment was performed. Bioinformatics predicted the microRNAs that bond with circCRIM1 and CRIM1, and dual luciferase reporter system confirmed it. Rescue experiments of microRNAs mimics transfection on the basis of circCRIM1 over-expression were carried out to uncover the mechanism by which circCRIM1 played cancer-promoting roles in ovarian cancer. Results CircCRIM1 was derived from CRIM1 by back-splicing. CircCRIM1 and CRIM1 had higher expression in ovarian cancer than in normal ovarian tissues, and both of them promoted ovarian cancer progression in vitro. In vivo circCRIM1 promoted the growth of tumors. CircCRIM1 and CRIM1 had a positive correlation relationship in the same cohort of ovarian cancer tissues. Bioinformatics predicted and dual luciferase assay confirmed circCRIM1 and CRIM1 bond with miR-145-5p, and circCRIM1 bond with miR-383-5p additionally. CircCRIM1 positively affected the expression of CRIM1. After circCRIM1 was over-expressed, miR-145-5p mimics transfection reversed the expression of CRIM1. Western blot discovered circCRIM1 positively affected the expression of zinc finger E-box binding homeobox 2 (ZEB2). Rescue experiments found miR-383-5p mimics reversed ZEB2 expression and the cancer-promoting effects of circCRIM1. Conclusions CircCRIM1 bond with miR-145-5p to work as competing endogenous RNA (ceRNA) of CRIM1, and circCRIM1 bond with miR-383-5p to improve the expression of ZEB2 in ovarian cancer. CircCRIM1 and CRIM1 promoted the ovarian cancer progression and supplied a novel insight into the researches of ovarian cancer.

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EXTH-03. COMBINED TOP1 AND PARP INHIBITION ENFORCES GENOMIC INSTABILITY AND CELL DEATH IN PTEN-DEFICIENT GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noab196.642 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi163-vi164

Author(s):

Olga Kim ◽

Madison Butler ◽

Ying Pang ◽

Guangyang Yu ◽

Mythili Merchant ◽

...

Keyword(s):

Dna Damage ◽

Cell Death ◽

Topoisomerase I ◽

Parp Inhibitor ◽

Annexin V ◽

Parp Inhibition ◽

Pten Loss ◽

Tensin Homolog

Abstract BACKGROUND Glioblastoma is an aggressive brain tumor with high mortality. The development of new therapies is critical for improving patient outcomes. LMP400, a novel topoisomerase I (TOP1) inhibitor, traps TOP1 cleavage complexes, thereby generating DNA damage. Poly(ADP-ribose) polymerase (PARP) is involved in DNA repair responses triggered by TOP1 inhibition. Niraparib is a potent PARP inhibitor that can cross the blood-brain barrier. Loss of phosphatase and tensin homolog (PTEN) occurs in 40% of GBM patients and is known to promote DNA damage repair deficiency. Here, we hypothesize that PTEN loss presents a vulnerability to a combined induction of DNA damage and inhibition of repair mechanisms. METHODS Human glioblastoma cells (U251, SNB-75, SF-295, LN18) and patient-derived glioblastoma stem cells (GSC923 and GSC827) were treated with LMP400 and/or Niraparib. Cell viability and apoptosis were examined using Celigo image cytometer and Annexin V/PI assay at 72h after treatment. Single clones after PTEN knockdown using shRNA were isolated after puromycin selection. For planned studies of PTEN knockout, sgRNA plasmids targeting PTEN will be transiently transfected and GFP-positive single KO clones will be isolated. PTEN will be restored in PTEN-null cells using lentiviral transduction. RESULTS CRISPR-Cas9 KO screening in GSC923 cells suggests that LMP400 is unlikely a substrate for ABC transporters. LMP400 and Niraparib synergistically induced cytotoxic effects in U251, SF-295, GSC923, GSC827 cells lacking PTEN expression. Combined LMP400/Niraparib led to increased expression of gamma-H2AX, cleaved caspase 3 and PARP, indicative of enhanced DNA damage and cell death. CONCLUSION LMP400 and Niraparib act synergistically to target PTEN-deficient glioblastoma by inducing DNA damage and cell death. These results will be further verified in isogenic cells in vitro as well as in vivo in a mouse model driven by PTEN deletion which would strongly support a novel therapeutic strategy in a subset of glioblastoma with PTEN loss.

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Drugs Targeting Tumor-Initiating Cells Prolong Survival in a Post-Surgery, Post-Chemotherapy Ovarian Cancer Relapse Model

Cancers ◽

10.3390/cancers12061645 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1645

Author(s):

Brittney S. Harrington ◽

Michelle K. Ozaki ◽

Michael W. Caminear ◽

Lidia F. Hernandez ◽

Elizabeth Jordan ◽

...

Keyword(s):

Oxidative Stress ◽

Ovarian Cancer ◽

Drug Metabolism ◽

Disease Recurrence ◽

Adherent Cells ◽

Sequencing Analysis ◽

Post Surgery ◽

Platinum Based Chemotherapy

Disease recurrence is the major cause of morbidity and mortality of ovarian cancer (OC). In terms of maintenance therapies after platinum-based chemotherapy, PARP inhibitors significantly improve the overall survival of patients with BRCA mutations but is of little benefit to patients without homologous recombination deficiency (HRD). The stem-like tumor-initiating cell (TIC) population within OC tumors are thought to contribute to disease recurrence and chemoresistance. Therefore, there is a need to identify drugs that target TICs to prevent relapse in OC without HRD. RNA sequencing analysis of OC cells grown in TIC conditions revealed a strong enrichment of genes involved in drug metabolism, oxidative phosphorylation and reactive oxygen species (ROS) pathways. Concurrently, a high-throughput drug screen identified drugs that showed efficacy against OC cells grown as TICs compared to adherent cells. Four drugs were chosen that affected drug metabolism and ROS response: disulfiram, bardoxolone methyl, elesclomol and salinomycin. The drugs were tested in vitro for effects on viability, sphere formation and markers of stemness CD133 and ALDH in TICs compared to adherent cells. The compounds promoted ROS accumulation and oxidative stress and disulfiram, elesclomol and salinomycin increased cell death following carboplatin treatment compared to carboplatin alone. Disulfiram and salinomycin were effective in a post-surgery, post-chemotherapy OC relapse model in vivo, demonstrating that enhancing oxidative stress in TICs can prevent OC recurrence.

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CBMT-19. THE ALTERNATIVE LENGTHENING OF TELOMERE (ALT) MECHANISM PROVIDES COLLATERAL SENSITIVITY TO LETHAL TELOMERIC FUSION INDUCED BY TRAPPING PARP INHIBITORS

Neuro-Oncology ◽

10.1093/neuonc/noz175.141 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi37-vi37

Author(s):

Joydeep Mukherjee ◽

Cecelia Dalle-Ore ◽

Tor-Christian Johanessen ◽

Ajay Pandita ◽

Shigeo Ohba ◽

...

Keyword(s):

Dna Damage ◽

Genomic Dna ◽

Parp Inhibitors ◽

Parp Inhibition ◽

Collateral Sensitivity ◽

Astrocytoma Cells ◽

Alternative Lengthening ◽

New Treatment

Abstract A subset of human tumors, including all IDH1-mutant astrocytomas, use a homologous recombination-based alternative lengthening of telomere (ALT) pathway to resolve telomeric dysfunction in the absence of TERT. Because ALT is not used by normal cells, targeting of the process may provide new therapeutic options for patients with ALT-dependent tumors. We here report that reliance on the ALT mechanism makes tumors collaterally hypersensitive to clinically-available trapping PARPi (t-PARPi). Specifically we noted that astrocytoma cells dependent on the ALT-mechanism (IDH1-mutant and ATRX-deficient genetically-modified human astrocytes and MGG119 PDX) were significantly more sensitive to trapping PARPi than matched ALT-independent isogenic ATRXWT astrocytes and MGG152 PDX cells, respectively) both in vitro and in vivo. Surprisingly this hypersensitivity was not associated with BRCA-ness, the extent of PARP inhibition, or with t-PARPi-created genomic DNA damage as is the case in most PARPi-sensitive populations. Rather the enhanced activity of t-PARPi in ALT-dependent cells was associated with a novel t-PARPi-induced, lethal telomere fusion. Furthermore, the extent of chromosomal fusion was proportional to the PARP-trapping ability of the five PARP inhibitors tested, and could be prevented by exogenous expression of TERT, which eliminated reliance on ALT but did not alter levels of PARPi-induced genomic DNA damage. The extent of tPARPi-induced telomeric fusion in ALT-dependent cells, which could be directly measured in small amounts of DNA using a q-PCR approach, was also directly proportional to tPARPi-induced cell death in vitro and to prolonged survival of tumor-bearing mice in vivo. These results therefore identify clinically available tPARPi as a new treatment modality for a select and easily genetically definable group of ALT tumors, and also define telomeric fusion as a biomarker of drug action in these tumors.

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