Validation and clinical discovery demonstration of breast cancer data from a real-world data extraction platform.

Objective: To validate and demonstrate the clinical discovery utility of a novel patient-mediated, medical record collection and data extraction platform developed to improve access and utilization of real-world clinical data. Materials and Methods: Clinical variables were extracted from the medical records of 1011 consented patients with breast cancer. To validate the extracted data, case report forms completed using the structured data output of the platform were compared to manual chart review for 50 randomly-selected patients with metastatic breast cancer. To demonstrate the platform's clinical discovery utility, we identified 194 patients with early-stage clinical data who went on to develop distant metastases and utilized the platform-extracted data to assess associations between time to distant metastasis (TDM) and early-stage tumor histology, molecular type, and germline BRCA status. Results: The platform-extracted data for the validation cohort had 97.6% precision (91.98%-100% by variable type) and 81.48% recall (58.15%-95.00% by variable type) compared to manual chart review. In our discovery cohort, the shortest TDM was significantly associated with metaplastic (739.0 days) and inflammatory histologies (1005.8 days), HR-/HER2- molecular types (1187.4 days), and positive BRCA status (1042.5 days) as compared to other histologies, molecular types, and negative BRCA status, respectively. Multivariable analyses did not produce statistically significant results. Discussion: The precision and recall of platform-extracted clinical data are reported, although specificity could not be assessed. The data can generate clinically-relevant insights. Conclusion: The structured real-world data produced by a novel patient-mediated, medical record-extraction platform are reliable and can power clinical discovery.

SPR-5 is a histone H3K4 demethylase with a role in meiotic double-strand break repair.

Regulation of histone methylation levels has long been implicated in multiple cellular processes, many of which involve transcription. Here, however, we report a unique role for the Caenorhabditis elegans histone demethylase SPR-5 in meiotic DNA double-strand break repair (DSBR). SPR-5 shows enzymatic activity toward H3K4me2 both in vitro and in the nematode germline, and spr-5 mutants show several phenotypes indicating a perturbation of DSBR, including increased p53-dependent germ cell apoptosis, increased levels of the DSBR marker RAD-51, and sensitivity toward DSB-inducing treatments. spr-5 mutants show no transcriptional misregulation of known DSBR involved genes. Instead, SPR-5 shows a rapid subcellular relocalization upon DSB-inducing treatment, which suggests that SPR-5 may function directly in DSBR.

A chromatin localization screen reveals poly (ADP ribose)-regulated recruitment of the repressive polycomb and NuRD complexes to sites of DNA damage.

Many proteins that respond to DNA damage are recruited to DNA lesions. We used a proteomics approach that coupled isotopic labeling with chromatin fractionation and mass spectrometry to uncover proteins that associate with damaged DNA, many of which are involved in DNA repair or nucleolar function. We show that polycomb group members are recruited by poly(ADP ribose) polymerase (PARP) to DNA lesions following UV laser microirradiation. Loss of polycomb components results in IR sensitivity of mammalian cells and Caenorhabditis elegans. PARP also recruits two components of the repressive nucleosome remodeling and deacetylase (NuRD) complex, chromodomain helicase DNA-binding protein 4 (CHD4) and metastasis associated 1 (MTA1), to DNA lesions. PARP plays a role in removing nascent RNA and elongating RNA polymerase II from sites of DNA damage. We propose that PARP sets up a transient repressive chromatin structure at sites of DNA damage to block transcription and facilitate DNA repair.

Redox sensor CtBP mediates hypoxia-induced tumor cell migration.

The rapid growth and poor vascularization of solid tumors expose cancer cells to hypoxia, which promotes the metastatic phenotype by reducing intercellular adhesion and increasing cell motility and invasiveness. In this study, we found that hypoxia increased free NADH levels in cancer cells, promoting CtBP recruitment to the E-cadherin promoter. This effect was blocked by pyruvate, which prevents the NADH increase. Furthermore, hypoxia repressed E-cadherin gene expression and increased tumor cell migration, effects that were blocked by CtBP knockdown. We propose that CtBP senses levels of free NADH to control expression of cell adhesion genes, thereby promoting tumor cell migration under hypoxic stress.

Reversal of histone lysine trimethylation by the JMJD2 family of histone demethylases.

Histone methylation regulates chromatin structure, transcription, and epigenetic state of the cell. Histone methylation is dynamically regulated by histone methylases and demethylases such as LSD1 and JHDM1, which mediate demethylation of di- and monomethylated histones. It has been unclear whether demethylases exist that reverse lysine trimethylation. We show the JmjC domain-containing protein JMJD2A reversed trimethylated H3-K9/K36 to di- but not mono- or unmethylated products. Overexpression of JMJD2A but not a catalytically inactive mutant reduced H3-K9/K36 trimethylation levels in cultured cells. In contrast, RNAi depletion of the C. elegans JMJD2A homolog resulted in an increase in general H3-K9Me3 and localized H3-K36Me3 levels on meiotic chromosomes and triggered p53-dependent germline apoptosis. Additionally, other human JMJD2 subfamily members also functioned as trimethylation-specific demethylases, converting H3-K9Me3 to H3-K9Me2 and H3-K9Me1, respectively. Our finding that this family of demethylases generates different methylated states at the same lysine residue provides a mechanism for fine-tuning histone methylation.