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Principal Investigator: ELISABETH D MARTINEZ
Organization: UT SOUTHWESTERN MEDICAL CENTER
Fiscal Year: 2024
Award: $82,000
Funding agency: National Cancer Institute
Close to 75% of all non-small cell lung cancer (NSCLC) patients receive radiation therapy at some point in their
treatment regimen whether with curative or palliative intent. Radiation, which is currently given in a highly
localized fashion, causes massive DNA damage leading to DSBs and cancer cell death, yet on its own is not yet
curative. Indeed, while some cancers are intrinsically resistant to IR, others acquire resistance by upregulating
DNA repair pathways. Given modern advances in the targeted administration of radiotherapy, a paradigm shift
leading to curing NSCLC or other tumors could occur if tumor tissue could be globally sensitized to radiation
therapy. The epigenetic susceptibilities we propose to investigate here, may be the key.
The oncogenic JARID/KDM5 histone demethylase subfamily of Jumonji enzymes, which are overexpressed in
multiple malignancies, have recently defined roles in the DNA damage pathway: they mediate DNA repair by
erasing trimethyl marks on active chromatin harboring H3K4me3 marks, thus stopping transcription and
facilitating the recruitment of both homologous recombination and non-homologous end joining repair factors.
The novel concept we propose here is that JARID enzymes must be modified post-translationally upon DNA
damage, likely by radiation-activated ATM or ATR kinases, to enhance their histone demethylating activity on
active chromatin, thus providing a mechanism to stop transcription and recruit repair factors to these sites, for
cancer-cell survival. If true, this novel oncogenic activity of JARID enzymes would have significant
implications for developing new approaches to sensitize lung tumors to ionizing radiation (IR), by selectively
inhibiting the enhanced demethylase activity of JARID enzymes on chromatin. Our specific aims are to:
1.Determine if JARID enzymes are substrates of ATM kinases during the DNA damage response to IR:
we will determine by mass spectrometry if JARID1B is phosphorylated by ATM/ATR kinases during the DNA
damage response. We will map the site of phosphorylation and will mutate it to alanine (loss of function) or
glutamic or aspartic acid (gain of function) to determine the impact on DNA repair dynamics, using isogenic
cells lines expressing endogenous wt JARID1B (as controls) or null for JARID1B (knock out cells available).
2.Define how oncogenic JARID enzyme activity is modulated by post-translational modifications: we will
measure the histone demethylase activity of unphosphorylated vs phosphorylated JARID1B enzyme in vitro
and in cells. We will also determine the genomic sites JARID1B associates with in control vs. in cells
undergoing DNA damage, and define if JARID1B recruitment to DSBs is dependent on phosphorylation.
Our study will thus have wide impact to lung cancer patients by providing the molecular and mechanistic
foundation for hypersensitizing tumors to radiation by using Jumonji inhibitors to curtail DNA repair through
blocking the histone signals that trigger this repair.
Terms: <ATM Protein><ATM Serine/Threonine Protein Kinase><ATM kinase><ATM protein kinase><Alanine><Aspartic Acid><Ataxia Telangiectasia Mutated><Ataxia Telangiectasia Protein><Ataxia-Telangiectasia-Mutated protein kinase><Cancer Patient><Cancers><Cell Body><Cell Communication and Signaling><Cell Death><Cell Line><Cell Signaling><Cell Survival><Cell Viability><CellLine><Cells><Chromatin><Consensus Sequence><DNA><DNA Damage><DNA Damage Repair><DNA Injury><DNA Repair><DNA Repair Pathway><Deoxyribonucleic Acid><Enzyme Gene><Enzymes><Epigenetic><Epigenetic Change><Epigenetic Mechanism><Epigenetic Process><Exposure to><Foundations><Gene Transcription><Generalized Growth><Genetic Transcription><Genomics><Glutamic Acid><Goals><Grant><Growth><Histones><In Vitro><Intracellular Communication and Signaling><Ionizing Electromagnetic Radiation><Ionizing radiation><JARID1B><Jumonji, AT-Rich Interactive Domain 1B><KDM5B><KDM5B gene><Kinases><Knock-out><Knockout><L-Aspartic Acid><L-Glutamic Acid><Local Therapy><Localized Therapy><Lung Neoplasms><Lung Tumor><Lysine-Specific Demethylase 5B><Malignant Cell><Malignant Neoplasms><Malignant Tumor><Malignant Tumor of the Lung><Malignant neoplasm of lung><Maps><Mass Photometry/Spectrum Analysis><Mass Spectrometry><Mass Spectroscopy><Mass Spectrum><Mass Spectrum Analyses><Mass Spectrum Analysis><Measures><Mediating><Modernization><Molecular><Mutate><NHEJ><NSCLC><NSCLC - Non-Small Cell Lung Cancer><Non-Homologous End Joining><Non-Small Cell Lung Cancer><Non-Small-Cell Lung Carcinoma><Non-homologous DNA End Joining><Nonhomologous DNA End Joining><Nonhomologous End Joining><Normal Tissue><Normal tissue morphology><Oncogenic><PLU-1 Protein><PLU1><PUT1><Pathway interactions><Phosphorylation><Phosphorylation Site><Phosphotransferase Gene><Phosphotransferases><Position><Positioning Attribute><Post-Translational Modification Protein/Amino Acid Biochemistry><Post-Translational Modifications><Post-Translational Protein Modification><Post-Translational Protein Processing><Posttranslational Modifications><Posttranslational Protein Processing><Predisposition><Protein Modification><Protein Phosphorylation><Pulmonary Cancer><Pulmonary Neoplasms><Pulmonary malignant Neoplasm><Putative DNA/Chromatin-Binding Motif 1><RBBP2H1A><RNA Expression><Radiation><Radiation therapy><Radiation-Ionizing Total><Radioresistance><Radiotherapeutics><Radiotherapy><Resistance><Resolution><Retinoblastoma-Binding Protein 2 Homolog 1A><Retinoblastoma-Binding Protein 2, Homolog 1A><Role><Signal Transduction><Signal Transduction Systems><Signaling><Site><Strains Cell Lines><Stress><Susceptibility><Therapeutic><Tissue Growth><Transcription><Transphosphorylases><Treatment Protocols><Treatment Regimen><Treatment Schedule><Tumor Tissue><Unscheduled DNA Synthesis><ataxia telangiectasia mutated protein><biological signal transduction><cancer cell><cultured cell line><demethylation><enzyme activity><enzyme substrate><epigenetically><gain of function><histone demethylase><homologous recombination><inhibitor><ionizing output><knock-down><knockdown><loss of function><lung cancer><malignancy><necrocytosis><neoplasm/cancer><new approaches><novel><novel approaches><novel strategies><novel strategy><ontogeny><overexpress><overexpression><palliative><pathway><radiation resistance><radiation treatment><radio resistance><recruit><repair><repaired><resistant><resolutions><response><social role><treatment with radiation><tumor>