Ataxia Telangiectasia Mutated Gene Research Articles

Pharmacodynamic (PD) and immunophenotyping analyses of ATR inhibitor (ATRi) tuvusertib + ATM inhibitor (ATMi) lartesertib in a phase Ib study in patients with advanced unresectable solid tumors.

2612 Background: Ataxia telangiectasia-mutated (ATM) and Rad3-related (ATR) protein kinases orchestrate the DNA damage response. A synthetic lethal relationship between ATR and ATM genes in cancer has been described1 and ATMi synergistically potentiate the efficacy of ATRi in vitro and in vivo.2 The combination of tuvusertib + lartesertib was investigated in Part A1 of the open-label, multicenter study DDRiver Solid Tumors 320 in patients with advanced unresectable solid tumors. Here, we report results of the PD and immunophenotyping analyses. Methods: PD analysis comprised γ-H2AX in serial blood samples, stimulated ex vivowith 4-NQO, bleomycin, or controls. Flow cytometry was used to measure target inhibition via γ-H2AX modulation in the CD45+ lymphocytes fraction and to explore the effect of tuvusertib + lartesertib on the immunophenotype (myeloid-derived suppressor cells, T and B lymphocytes, monocytes, and natural killer cells subsets) in serial blood samples. Pharmacokinetic samples were analyzed by a validated bioanalytical liquid chromatography/mass spectrometry method. Time-matched blood samples were collected at baseline, 1, 3, 6, and 24 hours after first tuvusertib and lartesertib administration on days 1 and 8 of cycle 1 for the γ-H2AX analysis, and on days 1 and 15 of cycles 1 and 2 before treatment for immunophenotyping. Results: Immunophenotyping data and γ-H2AX levels were obtained from 41 and 34 patients, respectively. For tuvusertib, complete or almost complete target inhibition was seen at 1–6 hours after treatment, followed by a rebound above baseline after 24 hours, on both days 1 and 8 at doses of 130 and 180 mg once daily (QD). For lartesertib, a variable target inhibition of approximately 50 % on average was seen across all time points at doses of 100, 150 and 200 mg QD. No target inhibition was seen for tuvusertib at 90 mg QD and lartesertib at 50 mg QD (cohort 1). Tuvusertib + lartesertib induced a transient decrease of monocytes and natural killer (NK) cells, with partial or complete recovery to baseline levels during treatment breaks in schedules of 2 weeks on treatment followed by a treatment break of 1 or 2 weeks, respectively. Conclusions: Tuvusertib and lartesertib combination PD outcomes were in line with respective monotherapy observations.3,4 The combination did not cause any consistent change in the levels of immune cell subsets at all dose levels tested, except a mild, transient decrease in monocytes and NK cells, in line with the tuvusertib monotherapy observations. 1. Kantidze et al., Trends Cancer 2018;4(11):755–68. 2. Turchick et al., Mol Cancer Ther 2023;22(7):859–72. 3. Yap et al., Ann Oncol 2022;33(suppl_7):S197–S224. 4. Siu et al., Cancer Res 2023;83(8_Suppl):CT171. Clinical trial information: NCT05396833 .

Abstract PO1-22-03: Radiation Toxicity and Treatment Outcomes in Breast Cancer Patients with ATM Pathogenic and VUS Mutations: Implications for Personalized Therapy

Abstract Introduction: Previous studies have shown that ATM (ataxia-telangiectasia mutated) mutations may be associated with increased radiation sensitivity and altered treatment response. However, there is a limited understanding of the clinical implications and optimal management strategies for breast cancer patients with ATM mutations receiving radiotherapy (RT). The aim of our study is to assess the impact of ATM mutations on radiation response and treatment outcomes in breast cancer patients undergoing RT. Material and Methods: A total of 79 female patients diagnosed with breast cancer were included in the study, with 31 (39.3%) having pathogenic (P) and likely pathogenic (LP) variants (all of the variants were heterozygous) and 48 (60.8%) having VUS variants detected through whole ATM gene sequencing screening for patients in accordance with NCCN clinical practice guideline. Statistical analysis, including descriptive, graphical, and inferential methods, such as the Kolmogorov-Smirnov test, Mann-Whitney U Test, and Chi-square tests, was conducted using SPSS version 25.0 to evaluate the normal distribution of continuous variable scores and perform quantitative and qualitative comparisons between groups at a 95% confidence level (p < 0.05). Results: The median age of the patients was 44 years (range: 24-74), with 75% of them being 50 years old or younger .The rate of breast cancer in patients with VUS variants was significantly higher in those aged 50 and below compared to those with P/LP variants (83% vs. 61%, p=0.028). There was no statistically significant difference in clinical stage, tumour histological type, and molecular subtype classification based on ATM gene variant type (P/LP vs. VUS) among the patients (p>0.05), but the rate of high tumour grade was significantly higher in the VUS variant group (65% vs. 40%, p=0.034). The rate of patients who received RT was 87%, with 26 patients receiving radiation to the breast or chest wall and 43 patients receiving additional regional lymph node irradiation. There were no statistically significant differences in surgical and systemic treatment types and RT dose based on ATM gene variant type (P/LP vs. VUS) (p>0.05). Among the patients who received RT, 33 (48%) experienced early-stage skin reactions, and 15 (22%) experienced late-stage skin reactions according to Common Terminology Criteria for Adverse Events (CTCAE) v5. No Grade 3, 4 and 5 early and late toxicity were observed . The rate of early (83% vs. 23%; p< 0.001) and late (35% vs. 13%; p=0.029) skin reactions was significantly higher in the P/LP variant group compared to the VUS variant group. Grade I lymphedema was observed in 2 (2.5%) patients, 1 (3.2%) in the P/LP group and 1 (2.1%) in the VUS group (p>0.05). Among the 23 patients who underwent breast reconstruction, 1 (4%) had implant revision and 1 (4%) experienced implant loss, both of which were observed in the pathogenic variant group (p>0.05). Conclusion: Limited clinical data exists on RT toxicity in breast cancer patients with ATM gene mutations, and clear guidelines for decision-making are lacking. Our study revealed higher rates of acute and chronic skin reactions in the P/LP variant group, highlighting the need for further investigation into the impact of these variants on treatment outcomes and patient management. However, it is crucial to manage these reactions effectively and not allow them to hinder treatment. Additional research and interventions are warranted to better understand and address these reactions, aiming to enhance the overall treatment experience and outcomes for patients with ATM gene mutations. Citation Format: Evrim Tezcanli, Seda Eroz, Ugur Ozbek, Ahmet Yesilyurt, CIHAN URAS, Nuran Bese. Radiation Toxicity and Treatment Outcomes in Breast Cancer Patients with ATM Pathogenic and VUS Mutations: Implications for Personalized Therapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-22-03.

Abstract PO1-10-01: Racial/Ethnic Disparities in Rates of Pathological Complete Response and Survival in Patients with Inflammatory Breast Cancer

Abstract Radiation Therapy Toxicities and Survival Outcomes in Monoallelic ATM Variant Carriers with Non-Metastatic Breast Cancer: A Retrospective Analysis Rayan Bensenane1 MD, Arnaud Beddok1,2,3 MD, Nadine Andrieu4 PhD, Fabienne Lesueur4 PhD, Eve Cavaciuti 4 MSc, Dorothee Le Gal4 MSc, Eon-Marchais Severine4 PhD, Dominique Stoppa Lyonnet 5MD PhD, Youlia Kirova1 MD 1. Institut Curie, PSL Research University, Radiation Oncology Department, Paris/Saint-Cloud/Orsay, France. 2. Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, 125 Nashua St., Boston, MA, 02114, USA 3. Institut Curie, PSL Research University, University Paris Saclay, Inserm LITO U1288 Orsay, France 4. Inserm, U900, Institut Curie, PSL Research University, Mines ParisTech, Paris, France 5.Department of Genetics, Institut Curie; Inserm U830, Institut Curie; Paris-Cité University Abstract (characters: 2952; max 3400 characters, not include spaces) Background: The Ataxia-Telangiectasia Mutated (ATM) gene, involved in the repair of DNA double-strand breaks, can contribute to radiosensitivity when a bi-allelic variant is present and lead to Ataxia-Telangiectasia syndrome. Moreover, monoallelic ATM pathologic variant (PV) carriers, especially women, has an estimated occurrence rate of 0.5-1% globally and face a 2 to 3-fold increased risk of developing breast cancer. Despite evidence of in vitro radiosensitivity in cells derived from monoallelic variant carriers, there is a dearth of patient studies examining the risk of radiation-induced toxicity. This study aims to explore radiation therapy (RT) toxicities in non-metastatic breast cancer women carrying a germline monoallelic ATM variant, compared to non-carriers. Methods: A retrospective study was conducted on patients treated at Institut Curie, Paris from 1999 to 2014 and participating to CoF-AT (a French national study) and GENESIS database. ATM variant screenings encompassed both PV and non-PV, with toxicities evaluated using CTCAE v.5. Variants were classified as pathogenic, variant of unknown significance (VUS), or benign. Follow-up started from age/date at breast cancer to acute, late toxicities, disease recurrence or last news. Survival and toxicity comparisons were made using Kaplan-Meier survival analysis and Chi-square tests, respectively, with a significance level of α set at 0.05. Results: Among 50 patients, nine were ATM variant carriers (3 PV/5 VUS/1 benign), and 41 were non-carriers. Most patients had no smoking history (68%), and invasive ductal carcinoma was the predominant diagnosis (82%). The majority underwent breast-conservative surgery (80%), and the dominant RT techniques were 3D-Conformational Radiation Therapy (70%) and Isocentric Lateral Decubitus (30%). The median RT dose was 50 Gy over an average period of 36.5 days. With a median follow-up of 12 years post-diagnosis, no significant difference in acute dermatitis, esophagitis, lymphedema, cutaneous fibrosis, telangiectasia, or heart disease was observed between the groups. Analysis of overall survival (OS) showed a 5-year OS of 98%, decreasing to 89% at 10 years. For ATM variant carriers, the OS at 5, 10, and 15 years was 100%, 89%, and 89%, respectively, similar to non-carriers. Kaplan-Meier analysis revealed no significant differences in 5, 10, and 15-year overall survival, progression-free survival, local failure-specific survival, and contralateral breast cancer rates between the groups. Conclusion: In non-metastatic breast cancer patients, monoallelic ATM variant carrier status does not significantly influence acute or late RT toxicities and survival outcomes. These findings, derived from a small cohort, highlight the need for prospective studies for further validation. Table: Acute and Late Toxicities Post-Radiation Therapy in Monoallelic ATM Variant Carriers vs Non-Carriers Citation Format: Rebecca Zasloff, Samantha Thomas, Kendra Parrish, Astrid Botty van de Bruele, Gayle DiLalla, Maggie DiNome, Laura Rosenberger, Hannah Woriax, E Shelley Hwang, Jennifer Plichta, Akiko Chiba. Racial/Ethnic Disparities in Rates of Pathological Complete Response and Survival in Patients with Inflammatory Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-10-01.

Abstract PO1-22-05: Radiation Therapy Toxicities and Survival Outcomes in Monoallelic ATM Variant Carriers with Non-Metastatic Breast Cancer: A Retrospective Analysis

Abstract Radiation Therapy Toxicities and Survival Outcomes in Monoallelic ATM Variant Carriers with Non-Metastatic Breast Cancer: A Retrospective Analysis Rayan Bensenane1 MD, Arnaud Beddok1,2,3 MD, Nadine Andrieu4 PhD, Fabienne Lesueur4 PhD, Eve Cavaciuti 4 MSc, Dorothee Le Gal4 MSc, Eon-Marchais Severine4 PhD, Dominique Stoppa Lyonnet 5MD PhD, Youlia Kirova1 MD 1. Institut Curie, PSL Research University, Radiation Oncology Department, Paris/Saint-Cloud/Orsay, France. 2. Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, 125 Nashua St., Boston, MA, 02114, USA 3. Institut Curie, PSL Research University, University Paris Saclay, Inserm LITO U1288 Orsay, France 4. Inserm, U900, Institut Curie, PSL Research University, Mines ParisTech, Paris, France Abstract (characters: 2952; max 3400 characters, not include spaces) Background: The Ataxia-Telangiectasia Mutated (ATM) gene, involved in the repair of DNA double-strand breaks, can contribute to radiosensitivity when a bi-allelic variant is present and lead to Ataxia-Telangiectasia syndrome. Moreover, monoallelic ATM pathologic variant (PV) carriers, especially women, has an estimated occurrence rate of 0.5-1% globally and face a 2 to 3-fold increased risk of developing breast cancer. Despite evidence of in vitro radiosensitivity in cells derived from monoallelic variant carriers, there is a dearth of patient studies examining the risk of radiation-induced toxicity. This study aims to explore radiation therapy (RT) toxicities in non-metastatic breast cancer women carrying a germline monoallelic ATM variant, compared to non-carriers. Methods: A retrospective study was conducted on patients treated at Institut Curie, Paris from 1999 to 2014 and participating to CoF-AT (a French national study) and GENESIS database. ATM variant screenings encompassed both PV and non-PV, with toxicities evaluated using CTCAE v.5. Variants were classified as pathogenic, variant of unknown significance (VUS), or benign. Follow-up started from age/date at breast cancer to acute, late toxicities, disease recurrence or last news. Survival and toxicity comparisons were made using Kaplan-Meier survival analysis and Chi-square tests, respectively, with a significance level of α set at 0.05. Results: Among 50 patients, nine were ATM variant carriers (3 PV/5 VUS/1 benign), and 41 were non-carriers. Most patients had no smoking history (68%), and invasive ductal carcinoma was the predominant diagnosis (82%). The majority underwent breast-conservative surgery (80%), and the dominant RT techniques were 3D-Conformational Radiation Therapy (70%) and Isocentric Lateral Decubitus (30%). The median RT dose was 50 Gy over an average period of 36.5 days. With a median follow-up of 12 years post-diagnosis, no significant difference in acute dermatitis, esophagitis, lymphedema, cutaneous fibrosis, telangiectasia, or heart disease was observed between the groups. Analysis of overall survival (OS) showed a 5-year OS of 98%, decreasing to 89% at 10 years. For ATM variant carriers, the OS at 5, 10, and 15 years was 100%, 89%, and 89%, respectively, similar to non-carriers. Kaplan-Meier analysis revealed no significant differences in 5, 10, and 15-year overall survival, progression-free survival, local failure-specific survival, and contralateral breast cancer rates between the groups. Conclusion: In non-metastatic breast cancer patients, monoallelic ATM variant carrier status does not significantly influence acute or late RT toxicities and survival outcomes. These findings, derived from a small cohort, highlight the need for prospective studies for further validation. Table: Acute and Late Toxicities Post-Radiation Therapy in Monoallelic ATM Variant Carriers vs Non-Carriers * Pearson/Chi2 test ; NS: non significant at α=0.05; ATM +/+: wild type for ATM; ATM +/- : ATM monoallelic germline variant carrier Citation Format: Rayan BENSENANE, Youlia Kirova, Arnaud BEDDOK, Andine ANDRIEU, Fabienne Lesueur, Eve CAVACIUTI, Dorothée Le GAL, Severine EON-MARCHAIS, Dominique STOPPA LYONNET. Radiation Therapy Toxicities and Survival Outcomes in Monoallelic ATM Variant Carriers with Non-Metastatic Breast Cancer: A Retrospective Analysis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-22-05.

Safety of the Breast Cancer Adjuvant Radiotherapy in Ataxia-Telangiectasia Mutated Variant Carriers.

The Ataxia-Telangiectasia Mutated (ATM) gene is implicated in DNA double-strand break repair. Controversies in clinical radiosensitivity remain known for monoallelic carriers of the ATM pathogenic variant (PV). An evaluation of the single-nucleotide polymorphism (SNP) rs1801516 (G-A) showed different results regarding late subcutaneous fibrosis after breast radiation therapy (RT). The main objective of this study was to evaluate acute and late toxicities in carriers of a rare ATM PV or predicted PV and in carriers of minor allele A of rs1801516 facing breast RT. Fifty women with localized breast cancer treated with adjuvant RT between 2000 and 2014 at Institut Curie were selected. Acute and late toxicities in carriers of a rare PV or predicted PV (n= 9), in noncarriers (n = 41) and in carriers of SNP rs1801516 (G-A) (n = 8), were examined. The median age at diagnosis was 53 years old and 82% of patients had an invasive ductal carcinoma and 84% were at clinical stage I-IIB. With a median follow-up of 13 years, no significant difference between carriers and noncarriers was found for acute toxicities (p > 0.05). The same results were observed for late toxicities without an effect from the rs1801516 genotype on toxicities. No significant difference in acute or late toxicities was observed between rare ATM variant carriers and noncarriers after breast RT for localized breast cancer.

Altered Ataxia-Telangiectasia Mutated Gene as a cause of endometriosis-associated ovarian clear cell carcinoma, novel pathogenic variant

Altered Ataxia-Telangiectasia Mutated Gene as a cause of endometriosis-associated ovarian clear cell carcinoma, novel pathogenic variant

Integrated network pharmacology and comprehensive bioinformatics identifying the mechanisms and molecular targets of Jieyu Anshen Granules for treating comorbidity with Alzheimer's disease and depression

Jieyu Anshen Granules (JY) is a traditional Chinese medicine formula commonly used as an adjuvant treatment for Alzheimer's disease (AD) complicated with depression. However, the specific underlying mechanisms and therapeutic targets of JY remain unclear. We used the TCMSP, TCMID, BATMAN-TCM, and other databases to screen the components and assumed targets of JY. Next, the GEO and DisGeNET databases were used to identify the related targets of both AD and Major Depressive Disorder (MDD). Enrichment analyses of core targets were performed, and the main components and core targets of JY for the comorbidity of AD and MDD were identified via protein–protein interaction (PPI) network construction and machine learning algorithms. Lastly, we verified binding affinity using the AutoDock software and molecular docking was performed. A total of 171 components were identified from JY, and 979 targets were obtained from the screening process. Bioinformatics analysis displayed 397 differentially expressed genes (DEGs) were shared by AD and MDD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis revealed significant enrichment of genes associated with neurotransmitter receptor activity, G protein-coupled amine receptor activity, as well as signaling pathways such as the cAMP signaling pathway, PI3K-Akt signaling pathway, and cholinergic synapses. Through the PPI network and machine learning, we identified three hub genes (Ataxia telangiectasia-mutated gene [ATM], Colony stimulating factor 1 receptor [CSF1R], EPH receptor B2 [EPHB2]) as potential therapeutic targets. Molecular docking confirmed that the components of JY (Mairin, Hederagenin, 3-Epioleanolic Acid) could effectively bind to multiple key targets. This study revealed the effective components and potential mechanisms associated with JY treatment regarding AD and MDD comorbidities, offering valuable insights into promising therapeutic targets for subsequent studies.

Generation of four gene-edited human induced pluripotent stem cell lines with mutations in the ATM gene to model Ataxia-Telangiectasia

Ataxia-Telangiectasia (A-T) is an autosomal recessive multi-system disorder caused by mutations in the ataxia-telangiectasia mutated (ATM) gene, resulting, among other symptoms, in neurological dysfunction. ATM is known to be a master controller of signal transduction for DNA damage response, with additional functions that are poorly understood. CRISPR/Cas9 technology was used to introduce biallelic mutations at selected sites of the ATM gene in human induced pluripotent stem cells (hiPSCs). This panel of hiPSCs with nonsense and missense mutations in ATM can help understand the molecular basis of A-T.

Progeroid syndromes : Aging, skin aging, and mechanisms of progeroid syndromes

Progeroid syndromes (PSs) are characterized by the premature onset of age-related pathologies. PSs display awide range of heterogeneous pathological symptoms that also manifest during natural aging, including vision and hearing loss, atrophy, hair loss, progressive neurodegeneration, and cardiovascular defects. Recent advances in molecular pathology have led to abetter understanding of the underlying mechanisms of these diseases. The genetic mutations underlying PSs are functionally linked to genome maintenance and repair, supporting the causative role of DNA damage accumulation in aging. While some of those genes encode proteins with adirect involvement in aDNA repair machinery, such as nucleotide excision repair (NER), others destabilize the genome by compromising the stability of the nuclear envelope, when laminA is dysfunctional in Hutchinson-Gilford progeria syndrome (HGPS) or regulate the DNA damage response (DDR) such as the ataxia telangiectasia-mutated (ATM) gene. Understanding the molecular pathology of progeroid diseases is crucial in developing potential treatments to manage and prevent the onset of symptoms. This knowledge provides insight into the underlying mechanisms of premature aging and could lead to improved quality of life for individuals affected by progeroid diseases.

The circular RNA Ataxia Telangiectasia Mutated regulates oxidative stress in smooth muscle cells in expanding abdominal aortic aneurysms

An abdominal aortic aneurysm (AAA) is a pathological widening of the aortic wall characterized by loss of smooth muscle cells (SMCs), extracellular matrix degradation, and local inflammation. This condition is often asymptomatic until rupture occurs, leading to high morbidity and mortality rates. Diagnosis is mostly accidental and the only currently available treatment option remains surgical intervention. Circular RNAs (circRNAs) represent a novel class of regulatory non-coding RNAs that originate from backsplicing. Their highly stable loop structure, combined with a remarkable enrichment in body fluids, make circRNAs promising disease biomarkers. We investigated the contribution of circRNAs to AAA pathogenesis and their potential application to improve AAA diagnostics. Gene expression analysis revealed the presence of deregulated circular transcripts stemming from AAA-relevant gene loci. Among these, the circRNA to the Ataxia Telangiectasia Mutated gene (cATM) was upregulated in human AAA specimens, in AAA-derived SMCs, and serum samples collected from aneurysm patients. In primary aortic SMCs, cATM increased upon angiotensin II and doxorubicin stimulation, while its silencing triggered apoptosis. Higher cATM levels made AAA-derived SMCs less vulnerable to oxidative stress, compared with control SMCs. These data suggest that cATM contributes to elicit an adaptive oxidative-stress response in SMCs and provides a reliable AAA disease signature.

Analysis of ATM germline mutations in solid tumors from Chinese patients.

10586 Background: Ataxia-telangiectasia mutated (ATM) is a tumor suppressor genes and plays an important role in the repair of DNA double-strand breaks (DSBs). Germ-line mutations of ATM gene result in the well-characterized ataxia telangiectasia syndrome, which manifests with an increased cancer predisposition, including a 20% to 30% lifetime risk of lymphoid, gastric, breast, central nervous system, skin, and other cancers. Novel therapies are in development that may improve the response to therapy of patients with ATM-deficient cancers including targeted therapy and immunotherapy. Nevertheless, the knowledge of incidence of ATM germline mutations in solid tumor remains poorly understood. Methods: We identified 19248 malignant solid tumors patients without selecting age or family history in a retrospective cohort. The pathogenicity of germline mutations was categorized based on American College of Medical Genetics and Genomics (ACMG) guidelines.The patients were divided into two groups, P/ LP group (with pathogenic or likely-pathogenic mutations), and Non-P/LP group (neither pathogenic nor likely-pathogenic mutation). Results: In 19248 patients with pan-cancer, 76 patients were found 76 heterozygous pathogenic or likely pathogenic germline mutations in ATM gene and the mutation frequency was 0.39%.Among these 76 carriers, 71 (93.4%) carried frameshift, nonsense or splice mutations (33 for frameshift,21 for missense and 17 for splice mutations). 4 carried missense mutations and 1 carried intron mutations. Eliminated a few types of cancers that had a smaller number (less than 50), the higher frequency of mutations contained cancers were pancreatic cancer (1.0%,7/692), breast cancer (0.71%,3/423), gastric cancer (0.6%,7/1094), The median age of group P/LP and non-P/LP group was 64 and 63 in pancreatic cancer，62 and 53 in breast cancer and 62 and 61 in gastric cancer. The three genes with the most somatic mutations were TP53, MUC16 and KRAS in P/LP group and were TP53, MUC16 and EGFR in non-P/LP group. There was no significant difference in mutation frequency of the four genes. The media TMB in P/LP group and non-P/LP group were 3.55 and 2.84 respectively and there was no statistical difference. In P/LP group，only one patients is high microsatellite instability who carryied a MLH1 and a ATM pathogenic mutation. Conclusions: This was the first report of the incidence of ATM germline mutations in Chinese solid tumors which expanded the understanding of ATM and provided a direction for clinical trial design of novel therapies. The relationship between germline mutations and cancer susceptibility will be studied in the future.

The landscape of ATM alteration in Chinese solid tumor patients.

e15147 Background: The Ataxia-telangiectasia mutated (ATM) gene is an oncosuppressor, which plays an important role in the repair of DNA double-strand breaks (DSBs). The mutation profiles of ATM gene in Chinese solid tumor patients can help understand pathogenesis, prognosis, and identify targets for therapy. Methods: Using commercial NGS assays, we retrospectively analyzed genomic DNA alterations in normal-paired samples from 1351 patients with malignancies from January 2021 to October 2022, and alterations including single base substitution, short and long insertion/deletions, copy number variations, gene fusions and rearrangements. Results: ATM gene was altered in 6.8% (92 of 1351) of all solid tumors. The frequency of ATM variations was assessed in multiple cancer types, including non-small cell lung cancer 22% (35/159), endometrial carcinoma 15% (2/13), biliary tract tumor 12.1% (7/58), gastric cancer 10.7% (3/28), prostatic cancer 8.3% (1/12), breast cancer 6.7% (2/30), colorectal cancer 6.5% (11/168), thyroid cancer 6.2% (5/80), cervical carcinoma 5.7% (2/35), prostatic cancer 3.9% (2/51), liver cancer 3% (2/66). A total 102 genetic alterations were identified in 92 patients, including 70 missense mutations (69%), 14 nonsense (14%), 9 splicing (9%), 3 frameshift (3%), 2 deletion (2%), 2 copy number variation (2%). Among these patients, 2 had pathogenic germline ATM heterozygous mutations, including one lung adenocarcinoma and one pancreatic cancer. Furthermore, in our cohort, ATM mutation carriers also owned other actionable mutation, the most frequent one was TP53 (41%), followed by APC (29%), KRAS (23%), MLL3 (22%) and BRCA2 (20%). Conclusions: Our findings indicate that ATM alterations are widely mutated in Chinese multiple cancer types, with specific mutations differing largely among different tumor types. ATM alterations warrant further investigation as predictive biomarkers of response to PARP inhibitors or platinum-based therapy.

TYPE OF ATM ABERRATION HAS A DIFFERENT IMPACT ON SURVIVAL PARAMETERS IN MANTLE CELL LYMPHOMA

Introduction: The ataxia–telangiectasia mutated (ATM) gene plays an important role in the cellular response to DNA damage. Whether different types of ATM aberrations (mutation and/or deletion of (del)11q) differentially affect survival in mantle cell lymphoma (MCL) has not yet been reported. Methods: We analyzed 160 consecutive MCL patients (pts) treated in two Czech university centers (Prague, Olomouc) from 11/2006 to 12/2021. Both fluorescence in situ hybridization (FISH) and next generation sequencing (NGS, Illumina), were performed in all pts to identify ATM and TP53 gene aberrations on tumoral tissue (peripheral blood, bone marrow); the cutoff value for ATM and TP53 mutation was 3% variant allele frequency. Peripheral blood and/or bone marrow had at least 5% MCL involvement as analyzed by flow cytometry. Variables were compared by chi-squared test. Kaplan-Meier method was used to calculate the probabilities of progression and overall survival (PFS, OS); the log rank test was used for univariate comparisons of survival curves. PFS and OS were calculated from the date of diagnosis. Results: The median age at diagnosis was 67 (30-87) years. All pts had advanced disease (IV). MIPI score was low, intermediate and high in 15.6%, 26.3% and 58.1% pts, respectively. Treatment approaches used were as follows: watch and wait in 5.0%, R-CHOP/R-CHOP-like in 50.6%, intensive R-HDAC-containing in 34.4% and non-anthracycline/palliative regimen in 10.0% of pts. Complete and partial response was achieved in 56.3% and 21.9% of pts, respectively. Stable and progressive disease was observed in 13.1% of pts. Almost 29% of pts underwent autologous stem cell transplant. Sixty percent of pts received rituximab maintenance. Overall, 71 (44.4%) and 68 (42.5%) pts had ATM and TP53 aberration(s) (del/mut/del+mut), respectively. Of these, 20 (12.5%) pts had aberrations in both genes. Disruption of ATM gene was related to B-symptoms (p≤0.005). Age, sex, ECOG PS, cytomorphology, Ki67 index, MIPI and treatment response did not correlate with ATM aberration. With a median follow-up of 3.8 years, 2-year PFS and 2-year OS in all pts was 58.1% and 74.6%, respectively. Median PFS in pts with ATM mutation, ATM deletion and ATM+TP53 aberration was not reached, 3.3 and 0.7 years, respectively (p ≤ 0.005). Median OS in pts with ATM mutation, ATM deletion and ATM+TP53 aberration was not reached, 5.6 and 0.9 years, respectively (p ≤ 0.005). No significant difference in OS was found between ATM mutated and wild-type pts. (Survival graph below) Keywords: aggressive B-cell non-Hodgkin lymphoma, diagnostic and prognostic biomarkers, indolent non-Hodgkin lymphoma The research was funded by: IGA_LF_2023_005, MH CZ DRO-VFN64165, IGA_LF_2023_010, MH_CZ-DRO (FNOL, 00098892) No conflicts of interests pertinent to the abstract.

Germline ATM Mutations Detected by Somatic DNA Sequencing in Lethal Prostate Cancer

BackgroundGermline mutations in the ataxia telangiectasia mutated (ATM) gene occur in 0.5–1% of the overall population and are associated with tumour predisposition. The clinical and pathological features of ATM-mutated prostate cancer (PC) are poorly defined but have been associated with lethal PC. ObjectiveTo report on the clinical characteristics including family history and clinical outcomes of a cohort of patients with advanced metastatic castration-resistant PC (CRPC) who were found to have germline ATM mutations after mutation detection by initial tumour DNA sequencing. Design, setting, and participantsWe acquired germline ATM mutation data by saliva next-generation sequencing from patients with ATM mutations in PC biopsies sequenced between January 2014 and January 2022. Demographics, family history, and clinical data were collected retrospectively. Outcome measurements and statistical analysisOutcome endpoints were based on overall survival (OS) and time from diagnosis to CRPC. Data were analysed using R version 3.6.2 (R Foundation for Statistical Computing, Vienna, Austria). Results and limitationsOverall, seven patients (n = 7/1217; 0.6%) had germline ATM mutations detected, with five of them having a family history of malignancies, including breast, prostate, pancreas, and gastric cancer; leukaemia; and lymphoma. Two patients had concomitant somatic mutations in tumour biopsies in genes other than ATM, while two patients were found to carry more than one ATM pathogenic mutation. Five tumours in germline ATM variant carriers had loss of ATM by immunohistochemistry. The median OS from diagnosis was 7.1 yr (range 2.9–14 yr) and the median OS from CRPC was 5.3 yr (range 2.2–7.3 yr). When comparing these data with PC patients sequenced by The Cancer Genome Atlas, we found that the spatial localisation of mutations was similar, with distribution of alterations occurring on similar positions in the ATM gene. Interestingly, these include a mutation within the FRAP-ATM-TRRAP (FAT) domain, suggesting that this represents a mutational hotspot for ATM. ConclusionsGermline ATM mutations are rare in patients with lethal PC but occur at mutational hotspots; further research is warranted to better characterise the family histories of these men and PC clinical course. Patient summaryIn this report, we studied the clinical and pathological features of advanced prostate cancers associated with germline mutations in the ATM gene. We found that most patients had a strong family history of cancer and that this mutation might predict the course of these prostate cancers, as well as response to specific treatments.

Stereotactic Radiosurgery for Brain Metastases in Patients With a Heterozygous Germline Ataxia Telangiectasia Mutated Gene

Germline mutations in the ataxia telangiectasia mutated (ATM) gene are associated with increased radiation sensitivity. Present literature lacks consensus on whether patients with heterozygous germline ATM mutations may be at greater risk of radiation-associated toxicities when treated with radiation therapy (RT), and there is little data considering more modern and conformal RT techniques such as stereotactic radiosurgery (SRS). Our report presents two cases of patients with heterozygous germline ATM mutations treated with SRS for brain metastases. One patient developed grade 3 radiation necrosis (RN) of an irradiated 16.3 cm3 resection cavity, but did not develop RN at other sites of punctate brain metastases treated with SRS. Similarly, the second report describes a patient who did not develop RN at any of the 31 irradiated sites of sub-centimeter (all ≤5 mm) brain metastases. The described cases demonstrate that some patients with germline ATM variants can safely undergo SRS for smaller brain metastases; however, clinical caution should be considered for patients with larger targets or a history of prior radiation toxicity. Given these findings and the lingering uncertainty surrounding the degree of radiosensitivity across ATM variants, future research is needed to determine whether more conservative dose-volume limits would potentially mitigate the risk of RN when treating larger brain metastases in this radiosensitive population.

Abstract 6208: Targeting DNA polymerase theta and ATM leads to synergistic killing of mantle cell lymphoma cells

Abstract Introduction: Rapid cell proliferation requires intact and faithful DNA damage repair mechanisms. DNA polymerase theta (POLQ) plays a key role in repairing DNA double-strand breaks through the microhomology-mediated end-joining (MMEJ), which is one of the three main pathways involved in repairing replication-induced double-strand breaks. Limited data have suggested that concurrent depletion of POLQ and ataxia-telangiectasia mutated (ATM) could be embryonic lethal. Hence, this phenomenon has the potential to be exploited for therapeutic benefit in cancers where ATM mutations are commonly seen. Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma marked by (11;14) translocation with ATM alterations seen in 40-50% of patients. There is an unmet need to find novel therapeutic strategies, especially in relapsed and/or refractory (R/R) MCL. Here, we investigated whether targeting POLQ and ATM could be a potential therapeutic strategy in MCL. Methods: In vitro studies were conducted by using MCL cell lines. CRISPR-Cas9 system was used to genetically deplete POLQ and ATM genes and sgRNAs co-expressing fluorescence markers were used to track the cell population with respective genotypes over time. Cell viability was assessed by CellTiter-Glo assay and flow cytometry. All cell lines were profiled for ATM expression and activity. A p-value of < 0.05 was considered statistically significant. The combination index of <1 was defined as synergistic. Results: CRISPR-Cas9-mediated depletion of POLQ significantly decreased cell proliferation in multiple MCL cell lines. In particular, Granta-519, which possesses a single copy of kinase-dead ATM that is reduced in expression, was most sensitive to POLQ depletion. Concurrent genetic depletion of ATM and POLQ resulted in a synergistic antiproliferative effect in ATM-proficient MCL cell lines. Subsequently, this cellular phenotype caused by the genetic intervention was recapitulated by using two POLQ inhibitors (novobiocin and ART558) and an ATM inhibitor (AZD0156). In vitro, single-agent treatment with novobiocin or ART558 caused a significant cytotoxic effect at physiologically relevant concentrations in ATM-deficient cells and co-treatment of novobiocin or ART558 with AZD0156 was synergistic in killing ATM-proficient MCL cells. Importantly, POLQ inhibitors significantly decreased the cell viability of MCIR1, which is an ibrutinib-resistant MCL cell line. Mechanistically, novobiocin or ART558 treatment induced gH2AX and cleaved PARP upregulation, which was further enhanced by ATM depletion, suggesting that co-inhibition of POLQ and ATM caused apoptosis due to the accumulation of unrepaired DNA damage. Conclusion: POLQ is a promising target in MCL, especially in ATM-deficient setting. In ATM-proficient MCL, targeting ATM and POLQ is synergistic. Our data has the potential to uncover novel biomarker-driven drug therapy of POLQ inhibitors in R/R MCL. Citation Format: Jithma Prasad Abeykoon, Shuhei Asada, Kalindi Parmar, Xiaosheng Wu, Thomas Witzig, Geoffrey Shapiro, Alan D. D'Andrea. Targeting DNA polymerase theta and ATM leads to synergistic killing of mantle cell lymphoma cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6208.

Breast cancer and mutation in the ataxia telangiectasia mutated gene: a case report

Among women, breast cancer is the most common cancer in the world, accounting for 25.7 % of all cancers and thus making it a topic of interest in public health. Breast cancer is a complex, heterogeneous genetic disease and, in the vast majority of cases, of unknown etiology. Around 7 % of breast cancer cases in the general population present a susceptibility gene mutation of Mendelian inheritance. The ataxia telangiectasia mutated (ATM) gene mutation is found inless than 1 % of the general population, and association studies conducted with controls have shown that these alleles are characterized by a moderate risk (RR: 2 ‐ 4) for hereditary cancer. Mutations in ATM incompletely cosegregate the disease, with an estimated 15 % of mutation carriers in this gene developing cancer. The incomplete penetrance of ATM, as wellas other moderate‐risk genes, supports that they follow a polygenic model of cancer susceptibility. We report the case of a 35‐year‐old woman diagnosed with metachronous bilateral breast carcinoma—T4b N1 M0 stage IIIB left breast and T1c N0 stage I right breast, intrinsic luminal B subtype, HER2 overexpression and pathogenic variant of ATM gene c.7913 G>A, p. Trp2638*—who was treated with neoadjuvant chemotherapy, followed by mastectomy, sentinel node biopsy and radiotherapy. The objective of this case report is to describe the clinicopathological characteristics of breast cancer and its association with moderate‐risk gene mutations.

Evaluation of Ataxia-Telangiectasia Mutated IVS10 Mutation in Breast Cancer Along with Clinicopathological Parameters.

Breast cancer is the most common cancer in women worldwide, with an estimated 2.26 million new cases diagnosed in 2020. The important genes associated include BRCA1, BRCA2, CHEK2, PTEN, TP53, and ataxia-telangiectasia mutated (ATM). ATM is responsible for repairing double-strand breaks in DNA making it a significant candidate in breast cancer predisposition. ATM variant, c.1066-6T>G, has been associated with an increased risk of breast cancer in some but not all studies. The Indian studies on the allele IVS10-6T>G are very limited. The present study was undertaken to evaluate the associations between c.1066-6T>G ATM gene variant and breast cancer incidence in Indian women and its correlation with histological grade, stage, and surrogate molecular classification. Routine histopathological processing was done after adequate fixation of the specimen followed by staining with hematoxylin and eosin and immunohistochemistry for ER, PR, Her2neu, and Ki67. Single-nucleotide polymorphism for ATM allele IVS10-6T>G was studied after DNA extraction, polymerase chain reaction amplification, and restriction enzyme digestion. All cases were found to be negative for ATM allele IVS10-6T>G mutation. Maximum number of patients (19 cases; 52.78%) had pT2 stage tumor followed by 11 patients (30.56%) with pT3. Majority of cases were luminal B (11; 30.56%) followed by triple negative (10; 27.78%). Although the results obtained by mutational analysis in the present study are not in agreement with the previous study on Indian women it agrees with the numerous previous studies and meta-analyses done on women with breast carcinoma in the Western world.

A Novel ATM Antisense Transcript ATM-AS Positively Regulates ATM Expression in Normal and Breast Cancer Cells

ObjectiveThe ataxia telangiectasia mutated (ATM) gene is a master regulator in cellular DNA damage response. The dysregulation of ATM expression is frequent in breast cancer, and is known to be involved in the carcinogenesis and prognosis of cancer. However, the underlying mechanism remains unclear. The bioinformatic analysis predicted a potential antisense transcript ATM-antisense (AS) from the opposite strand of the ATM gene. The purpose of this study was to identify ATM-AS and investigate the possible effect of ATM-AS on the ATM gene regulation.MethodsSingle strand-specific RT-PCR was performed to verify the predicted antisense transcript ATM-AS within the ATM gene locus. qRT-PCR and Western blotting were used to detect the expression levels of ATM-AS and ATM in normal and breast cancer cell lines as well as in tissue samples. Luciferase reporter gene assays, biological mass spectrometry, ChIP-qPCR and RIP were used to explore the function of ATM-AS in regulating the ATM expression. Immunofluorescence and host-cell reactivation (HCR) assay were performed to evaluate the biological significance of ATM-AS in ATM-mediated DNA damage repair. Breast cancer tissue samples were used for evaluating the correlation of the ATM-AS level with the ATM expression as well as prognosis of the patients.ResultsThe ATM-AS significantly upregulated the ATM gene activity by recruiting KAT5 histone acetyltransferase to the gene promoter. The reduced ATM-AS level led to the abnormal downregulation of ATM expression, and impaired the ATM-mediated DNA damage repair in normal breast cells in vitro. The ATM-AS level was positively correlated with the ATM expression in the examined breast cancer tissue samples, and the patient prognosis.ConclusionThe present study demonstrated that ATM-AS, an antisense transcript located within the ATM gene body, is an essential positive regulator of ATM expression, and functions by mediating the binding of KAT5 to the ATM promoter. These findings uncover the novel mechanism underlying the dysregulation of the ATM gene in breast cancer, and enrich our understanding of how an antisense transcript regulates its host gene.

Hexavalent chromium triggers hepatocytes premature senescence via the GATA4/NF-κB signaling pathway mediated by the DNA damage response

Hexavalent chromium [Cr(VI)] is a proven toxin, carcinogen and environmental pollutant. Oral intake of Cr(VI) has been shown to lead to an increasing incidence of primary hepatic carcinoma in the population. Cellular senescence is thought to be a natural barrier to malignant transformation of cells, but senescence-associated secretory phenotype (SASP) is secreted and regulated by senescent cells links cellular senescence to malignant transformation in a dynamic way. In the present research, we demonstrated novel mechanisms of premature hepatocytes senescence induced by Cr(VI). Continuous Cr(VI) stimulation led to DNA damaged in hepatocytes, and DNA damage response (DDR) signals were transmitted by ataxia telangiectasia-mutated gene (ATM)/ataxia telangiectasia and Rad-3-related protein (ATR), resulting in zinc finger transcription factor GATA4 escaping p62-mediated selective autophagy, thereby regulating nuclear factor kappa-B (NF-κB) to induce premature senescence in hepatocytes. In contrast to the classical senescence pathway p53-p21WAF1 /CIP1 and Rb/p16INK4a, GATA4 can directly regulate the secretion of SASP during premature senescence. The results will provide valuable clues for targeted prevention and further individualized treatment of Cr(VI)-associated cancers.