Abstract AP10: REAL-TIME ASSESSMENT OF HGSC DNA DAMAGE REPAIR DEFECTS AND DEFECT-INDUCED RESPONSE TO THERAPY IN OVARIAN CANCER ORGANOIDS

DNA damage-inducing therapies are of tremendous value for cancer treatment and function by the direct or indirect formation of DNA lesions and subsequent inhibition of cellular proliferation. Of central importance in the cellular response to therapy-induced DNA damage is the DNA damage response (DDR), a protein network guiding both DNA damage repair and the induction of cancer-eradicating mechanisms such as apoptosis. A detailed understanding of DNA damage induction and the DDR has greatly improved our knowledge of the classical DNA damage-inducing therapies, radiotherapy and cytotoxic chemotherapy, and has paved the way for rational improvement of these treatments. Moreover, compounds targeting specific DDR proteins, selectively impairing DNA damage repair in cancer cells, form a promising novel therapy class that is now entering the clinic. In this review, we give an overview of the current state and ongoing developments, and discuss potential avenues for improvement for DNA damage-inducing therapies, with a central focus on the role of the DDR in therapy response, toxicity and resistance. Furthermore, we describe the relevance of using combination regimens containing DNA damage-inducing therapies and how they can be utilized to potentiate other anticancer strategies such as immunotherapy.

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Tumor Cell–Accelerated Senescence Is Associated With DNA-PKcs Status and Telomere Dysfunction Induced by Radiation

Dose-Response ◽

10.1177/1559325818771527 ◽

2018 ◽

Vol 16 (2) ◽

pp. 155932581877152 ◽

Cited By ~ 3

Author(s):

Miaomiao Zhang ◽

Xiaopeng Guo ◽

Yue Gao ◽

Dong Lu ◽

Wenjian Li

Keyword(s):

Dna Damage ◽

Real Time ◽

Genome Instability ◽

Dna Damage Repair ◽

Cancer Cell Line ◽

Histochemical Staining ◽

Damage Repair ◽

Radiation Induced ◽

Accelerated Senescence ◽

Mcf 7

Whether telomere structure integrity is related to radiosensitivity is not well investigated thus far. In this study, we investigated the relation between telomere instability and radiation-induced accelerated senescence. Partial knockdown of DNA-dependent catalytic subunit of protein kinase (DNA-PKcs) in human breast cancer cell line MCF-7 was established by small interfering RNA. Radiosensitivity of control and DNA-PKcs knockdown MCF-7 cells was analyzed by clonogenetic assay. Cell growth was measured by real-time cell electronic sensing. Senescence and apoptosis were evaluated by β-galactosidase histochemical staining and fluorescence-activated cell sorting, respectively. DNA damage was determined by long polymerase chain reaction (PCR). Telomere length and integrity were analyzed by real-time PCR and cytogenetic assay, respectively. DNA-PKcs knockdown MCF-7 cells were more sensitive to X-irradiation than control cells. Further investigation revealed that accelerated senescence is more pronounced than apoptosis in cells after radiation, particularly in DNA-PKcs knockdown cells. The cytogenetic assay and kinetics of DNA damage repair revealed that the role of telomere end-capping in DNA-PKcs, rather than DNA damage repair, was more relevant to radiosensitivity. To our knowledge, this is the first study to show that DNA-PKcs plays an important role in radiation-induced accelerated senescence via maintenance of telomere integrity in MCF-7 cells. These results could be useful for future understanding of the radiation-induced genome instability and its consequences.

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Genomic characterization of brain metastases (BM) in high-grade serous ovarian cancer (HGSOC).

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.e13580 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. e13580-e13580

Author(s):

Renata Duchnowska ◽

Anna Maria Supernat ◽

Rafał Pęksa ◽

Marta Łukasiewicz ◽

Tomasz Stokowy ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Somatic Mutations ◽

Dna Damage Repair ◽

Genetic Alterations ◽

High Grade ◽

Serous Ovarian Cancer ◽

Primary Tumors ◽

Tp53 Mutations ◽

Damage Repair

e13580 Background: BM are a rare occurrence in ovarian cancer (OC) and their molecular characteristics is virtually unknown. DNA damage repair (DDR) deficiency is prevalent in OC, and co-mutated TP53 and any DDR denotes high tumor mutation burden (TMB). We genetically characterized a unique series of high-grade serous ovarian cancer (HGSOC) patients who developed BM to identify alterations of potential clinical relevance. Methods: Whole-exome sequencing (2x150bp, SureSelectXT Library Prep Kit, Illumina’s NovaSeq platform) was performed in matched BM, primary tumors (PT) and normal tissue. DNA was extracted from FFPE samples using QIAamp DNA FFPE Tissue Kit (Qiagen, Germany). All mutations were checked with Catalogue of Somatic Mutations in Cancer (COSMIC) and Integrative Genomics Viewer (IGV). Results: Study group included 10 HGSOC patients (International Federation of Gynecology and Obstetrics classification (FIGO) II-IV, mean age at diagnosis 48 years, range 35-59). Median time from primary HGSOC diagnosis to BM was 38 months (range, 18 to 149). TP53 somatic mutations were found in both primary tumor (PT) and BM in 8 patients. The other 2 cases harbored TP53 mutations not reported in COSMIC catalogue: p.S60L and intronic TP53 mutation preceding p.I322 (IGV). In 9 cases TP53 mutations coexisted with germline or somatic DNA damage repair deficiency. Four cases contained BRCA1 mutations (all germline), and none harbored germline BRCA2 mutation. Other mutated genes included MLH1 (2 somatic, 2 germline), ATR (4 germline, 1 somatic), AMT (1 somatic), RAD50 (1 somatic), ERCC4 (1 somatic), FANCD2 (1 somatic) and RPA1 (1 germline). Three mutation signatures defined in the COSMIC database were indentified in BM: 6, 20 and 30. In 6 cases these mutations were shared in PT, and in another 4 their presence in PT could not be determined due to technical reasons. Median survival from BM was 31 months (range, 5 to 184). Conclusions: Genomic analysis of BM provides an opportunity to identify potentially clinically informative alterations. Mutational profiles in PT are generally reflected in BM. Detected genetic alterations suggest their potential sensitivity to PARP inhibitors and immunotherapy.

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Bruceine D and Afatinib Combination Inhibits Ovarian Cancer Cells Proliferation and Migration Through DNA Damage Repair and EGFR Pathway

10.21203/rs.3.rs-1052397/v1 ◽

2021 ◽

Author(s):

Feng Lin ◽

Ju-fan Zhu ◽

Luo Wang ◽

Yuan-jun Yang ◽

Ru-ru Zheng ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Cancer Patients ◽

Cancer Cell ◽

Ovarian Cancer Cell ◽

Dna Damage Repair ◽

Egfr Signaling ◽

Damage Repair ◽

And Migration ◽

Proliferation And Migration

Abstract Owing to the high rates of relapse and migration, ovarian cancer has been recognized as the most lethal gynecological malignancy worldwide. The activity of the EGFR signaling pathway is frequently associated with ovarian cancer cell proliferation and migration. Despite this knowledge, inhibition of EGFR signaling in ovarian cancer patients failed to achieve satisfactory therapeutic effects. In this study, we identified that Bruceine D and EGFR inhibitor, afatinib, combination resulted in synergistic anti- ovarian cancer effects. The results indicated that compared with one of both drugs alone, the combination of Bruceine D and afatinib slowed the DNA replication rate, inhibition of cell viability, and proliferation and clone formation. This resulted in cell cycle arrest and cell apoptosis. In addition, the combination of Bruceine D and afatinib possessed a stronger ability to inhibit the ovarian cancer cell adhesion and migration than treatment with Bruceine D or afatinib alone. Mechanistically, the combined treatment triggered intense DNA damage, suppressed DNA damage repair, and enhanced the inhibition of the EGFR pathway. These results demonstrated that compared with each pathway inhibition, combined blocking of both DNA damage repair and the EGFR pathway appears to more effective against ovarian cancer treatment. The results support the potential of Bruceine D and afatinib combination as a therapeutic strategy for ovarian cancer patients.

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Association of high tumor mutation (TMB) with DNA damage repair (DDR) alterations and better prognosis in ovarian cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.15_suppl.5512 ◽

2018 ◽

Vol 36 (15_suppl) ◽

pp. 5512-5512 ◽

Cited By ~ 4

Author(s):

Wenjuan Tian ◽

Boer Shan ◽

Yuzi Zhang ◽

Yulan Ren ◽

Shanhui Liang ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Dna Damage Repair ◽

Damage Repair

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EPV007/#582 DNA damage repair is altered by inhibition of discoidin domain receptor 2 (DDR2) through metabolic rewiring in homologous-recombination proficient ovarian cancer models

10.1136/ijgc-2021-igcs.74 ◽

2021 ◽

Author(s):

E Stock ◽

K Cho ◽

E Lomonosova ◽

A Schab ◽

A Oplt ◽

...

Keyword(s):

Ovarian Cancer ◽

Dna Damage ◽

Homologous Recombination ◽

Dna Damage Repair ◽

Discoidin Domain Receptor ◽

Damage Repair ◽

Cancer Models ◽

Discoidin Domain Receptor 2

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EPCO-04. RADIOTHERAPY IS ASSOCIATED WITH GLOBAL METHYLATION ALTERATIONS IN PATIENT DERIVED GLIOBLASTOMA CELL LINES

Neuro-Oncology ◽

10.1093/neuonc/noab196.003 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi2-vi2

Author(s):

Aram Modrek ◽

David Byun ◽

Ravesanker Ezhilarasan ◽

Matija Snuderl ◽

Erik Sulman

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Dna Damage ◽

Radiation Treatment ◽

Cpg Islands ◽

Dna Damage Repair ◽

Differential Methylation ◽

Response To Therapy ◽

Damage Repair ◽

Genomic Regions

Abstract PURPOSE/OBJECTIVE(S) In glioblastoma, DNA methylation states are the most predictive marker of overall survival and response to therapy. Our understanding of how epigenetic states, such as DNA methylation, are “mis-repaired” after DNA damage repair is scant, hampering our ability to understand how treatment associated DNA methylation alterations may drive tumor resistance and growth. MATERIALS AND METHODS Three different patient derived IDH wild-type glioma stem cell (GSC) lines, in duplicates, were treated with radiation (20 Gray in 10 fractions vs. sham control) and allowed to recover prior to DNA methylation analysis with 850K methylation arrays. To analyze the methylation array data via bioinformatic methods we used RnBeads (version 2.4.0) and R (version 3.6.1) packages. We further focused our analysis to specific genomic regions, including CpG islands, promoters, gene bodies and CTCF motifs to understand how methylation alterations may differ between these and other genomic contexts following radiation. RESULTS There were widespread differential methylation (pre-treatment vs. radiation treatment) changes among the genomic regions examined. Interestingly, we found differential methylation changes at CTCF motifs, which play important DNA-methylation dependent roles in gene expression and chromatin architecture regulation. Hierarchical clustering, PCA and MDS analysis of DNA methylation status amongst CpG islands, promoters, gene bodies and CTCF domains revealed strong intra-sample differences, but not inter-sample differences (between GSC lines), suggesting radiation associated methylation alterations maybe loci and context dependent. CONCLUSION Radiation treatment is associated with wide-spread alterations of DNA methylation states in this patient derived glioblastoma model. Such alterations may drive gene expression changes or genomic architecture alterations that lead to treatment resistance, warranting further mechanistic investigation of the interplay between radiation induced DNA damage and local epigenetic state restoration following DNA damage repair.

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