DNA Repair and Genome Stability
Wioletta Czaja, PhD
Nearly all forms of cancer (~90%) contain significant levels of genomic instability (high frequency of mutations, chromosomal rearrangements), largely resulting from deficient or dysregulated DNA repair processes. The molecular events leading to genomic instability are not well understood. We investigate the fundamental mechanisms protecting genomic integrity, with a special focus on the epigenetic and chromatin-based regulation of DNA damage and repair. The long-term objective of our research is to understand how stability of the human genome is maintained and regulated in various cellular and tissue contexts to promote advances in novel anticancer therapy and personalized medicine. We employ modern approaches in biochemistry, cell and molecular biology, genetics and genomics using fungal model organisms and human cell lines.
New tools in cancer risk identification and prevention. Alkyl DNA adducts are cytotoxic and mutagenic DNA lesions that arise from exposure of cells to numerous environmental carcinogens and cellular metabolites. Some of the most toxic alkyl DNA adducts are induced by commonly used anti-cancer drugs. DNA modifications induced by alkylating agents play significant roles in both the development and treatment of cancer. To understand how alkyl DNA adducts contribute to mutagenesis, cancer development and treatment, it is imperative to be able to examine complete, genome-wide profiles of these lesions and investigate how factors (such as modifications of chemotherapy agents, or the genomic and epigenomic landscape of the cell) influence initial adduct formation and repair. We are working on development of ADA-SMRT, a new methodology enabling direct detection of carcinogenic alkyl DNA adducts (ADA) by using SMRT DNA sequencing. The development of ADA-SMRT sequencing will enable, for the first time, direct and simultaneous high throughput mapping of various alkyl DNA adducts in eukaryotic genomes. This research will provide a framework for future investigation of the human genome and better understanding of the individual differences in cancer predisposition and response to chemotherapy.
Role of HELLS chromatin remodeler in genome maintenance and cancer. Identification of novel regulators of genome stability is highly relevant for advancing fundamental understanding of cancer biology and development of more effective treatments. DNA alkylation damage is the major threat to genome stability and human health. Cellular responses to alkylation DNA damage are poorly understood in human cells. Human HELLS (Helicase Lymphoid Specific) is a member of conserved SNF2-like family of ATP-dependent chromatin remodelers. HELLS has been implicated in many cancers (glioblastoma, hepatocellular carcinoma, leukemia) and human ICF syndrome (immunodeficiency, centromeric instability, facial abnormalities). Our data suggest that HELLS is chromatin-based regulator of alkylation DNA damage response and genome stability. Our preliminary work with human cells suggests the important role of HELLS in response to alkylation DNA damage and implies new role in the repair/ stability of centromeres following DNA damage. The goals of this research are to elucidate the molecular and cellular mechanisms of HELLS-dependent genome maintenance by combining complementary approaches in fungal epigenetic model organism and human cells.
R21 NIH NIEHS 1R21ES02854901A1 (active)
GIA Grants in aid, HI-UMN equipment grant for purchase of BioRad ChemiDoc MP imaging system