Checkpoint Kinase-Dependent Regulation of DNA Repair and Genome Instability in Breast Cancer

2009 ◽  
Author(s):  
Courtney A. Lovejoy
Keyword(s):  
Breast Cancer ◽  
Dna Repair ◽  
Genome Instability ◽  
Checkpoint Kinase

scholarly journals Genome Instability and Pressure on Non-Homologous end Joining drives Chemotherapy Resistance via a DNA Repair Crisis Switch in Triple Negative Breast Cancer.

2020 ◽  
Author(s):  
Adrian Wiegmans ◽  
Ambber Ward ◽  
Ekaterina Ivanova ◽  
Pascal H G Duijf ◽  
Romy VanOosterhout ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Genome Instability ◽  
Chemotherapy Resistance ◽  
End Joining ◽  
Repair Pathways ◽  
Non Homologous End Joining

Abstract Background: Chemotherapy intensifies pressure on the DNA repair pathways that can lead to deregulation. There is an urgent clinical need to be able to track the emergence of chemotherapy resistance and tailor patient staging appropriately. This is especially evident in the triple negative breast cancer (TNBC) subtype, of which standard of care is chemotherapy with tumours displaying high levels of inherent genome instability. TNBC has an overall poor prognosis for survival. There have been numerous studies into single agent chemoresistance but to date no study has elucidated in detail the roles of the key DNA repair components in resistance associated with the frontline clinical combination of anthracyclines and taxanes together. Methods: In this study, we hypothesized that the emergence of chemotherapy resistance is driven by changes in functional signaling in the DNA repair pathways. We identified the importance of the DNA repair pathways in chemoresistant clinical samples and characterized the emergence of chemoresistance in TNBC cell lines. We utilized classical DNA repair assays and specific targeting of key DNA repair proteins to elucidate a new mechanism for adaptation to the combination of doxorubicin and docetaxel. Results: We identified that consistent pressure on the non-homologous end joining pathway in the presence of genome instability causes failure of the key kinase DNA-PK, loss of p53 and compensation by p73. In-turn a switch to reliance on the homologous recombination pathway and RAD51 recombinase occurs to repair residual double strand DNA breaks. Conclusions: We demonstrate that RAD51 is an actionable target for resensitization to chemotherapy in resistant cells with a matched gene expression profile of resistance highlighted by homologous recombination.

scholarly journals Genome instability and pressure on non-homologous end joining drives chemotherapy resistance via a DNA repair crisis switch in triple negative breast cancer

NAR Cancer ◽  
2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Adrian P Wiegmans ◽  
Ambber Ward ◽  
Ekaterina Ivanova ◽  
Pascal H G Duijf ◽  
Mark N Adams ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Genome Instability ◽  
Chemotherapy Resistance ◽  
End Joining ◽  
Repair Pathways ◽  
Non Homologous End Joining

Abstract Chemotherapy is used as a standard-of-care against cancers that display high levels of inherent genome instability. Chemotherapy induces DNA damage and intensifies pressure on the DNA repair pathways that can lead to deregulation. There is an urgent clinical need to be able to track the emergence of DNA repair driven chemotherapy resistance and tailor patient staging appropriately. There have been numerous studies into chemoresistance but to date no study has elucidated in detail the roles of the key DNA repair components in resistance associated with the frontline clinical combination of anthracyclines and taxanes together. In this study, we hypothesized that the emergence of chemotherapy resistance in triple negative breast cancer was driven by changes in functional signaling in the DNA repair pathways. We identified that consistent pressure on the non-homologous end joining pathway in the presence of genome instability causes failure of the key kinase DNA-PK, loss of p53 and compensation by p73. In-turn a switch to reliance on the homologous recombination pathway and RAD51 recombinase occurred to repair residual double strand DNA breaks. Further we demonstrate that RAD51 is an actionable target for resensitization to chemotherapy in resistant cells with a matched gene expression profile of resistance highlighted by homologous recombination in clinical samples.

Truncating variants in DNA-repair genes and their effect on AAO of hereditary breast cancer

2018 ◽  
Author(s):  
I Sepahi ◽  
U Faust ◽  
M Sturm ◽  
K Bosse ◽  
M Kehrer ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Dna Repair ◽  
Hereditary Breast Cancer ◽  
Dna Repair Genes ◽  
Repair Genes

scholarly journals Single Cell Genetic Profiling of Tumors of Breast Cancer Patients Aged 50 Years and Older Reveals Enormous Intratumor Heterogeneity Independent of Individual Prognosis

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3366
Author(s):  
Anna-Sophie Liegmann ◽  
Kerstin Heselmeyer-Haddad ◽  
Annette Lischka ◽  
Daniela Hirsch ◽  
Wei-Dong Chen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Copy Number ◽  
Genome Instability ◽  
Single Cells ◽  
Gene Mutations ◽  
Intratumor Heterogeneity ◽  
Breast Cancer Patients ◽  
Luminal A ◽  
Pik3ca Mutations

Purpose: Older breast cancer patients are underrepresented in cancer research even though the majority (81.4%) of women dying of breast cancer are 55 years and older. Here we study a common phenomenon observed in breast cancer which is a large inter- and intratumor heterogeneity; this poses a tremendous clinical challenge, for example with respect to treatment stratification. To further elucidate genomic instability and tumor heterogeneity in older patients, we analyzed the genetic aberration profiles of 39 breast cancer patients aged 50 years and older (median 67 years) with either short (median 2.4 years) or long survival (median 19 years). The analysis was based on copy number enumeration of eight breast cancer-associated genes using multiplex interphase fluorescence in situ hybridization (miFISH) of single cells, and by targeted next-generation sequencing of 563 cancer-related genes. Results: We detected enormous inter- and intratumor heterogeneity, yet maintenance of common cancer gene mutations and breast cancer specific chromosomal gains and losses. The gain of COX2 was most common (72%), followed by MYC (69%); losses were most prevalent for CDH1 (74%) and TP53 (69%). The degree of intratumor heterogeneity did not correlate with disease outcome. Comparing the miFISH results of diploid with aneuploid tumor samples significant differences were found: aneuploid tumors showed significantly higher average signal numbers, copy number alterations (CNAs) and instability indices. Mutations in PIKC3A were mostly restricted to luminal A tumors. Furthermore, a significant co-occurrence of CNAs of DBC2/MYC, HER2/DBC2 and HER2/TP53 and mutual exclusivity of CNAs of HER2 and PIK3CA mutations and CNAs of CCND1 and PIK3CA mutations were revealed. Conclusion: Our results provide a comprehensive picture of genome instability profiles with a large variety of inter- and intratumor heterogeneity in breast cancer patients aged 50 years and older. In most cases, the distribution of chromosomal aneuploidies was consistent with previous results; however, striking exceptions, such as tumors driven by exclusive loss of chromosomes, were identified.

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