Autoreactive B cell-derived antibodies form immune complexes that likely play a pathogenic role in autoimmune diseases. In systemic lupus erythematosus (SLE), these antibodies bind Fc receptors on myeloid cells and induce proinflammatory cytokine production by monocytes and NETosis by neutrophils. Bruton’s tyrosine kinase (BTK) is a non-receptor tyrosine kinase that signals downstream of Fc receptors and plays a transduction role in antibody expression following B cell activation. Given the roles of BTK in both the production and sensing of autoreactive antibodies, inhibitors of BTK kinase activity may provide therapeutic value to patients suffering from autoantibody-driven immune disorders. Starting from an in-house proprietary screening hit followed by structure-based rational design, we have identified a potent, reversible BTK inhibitor, BIIB068 (1), which demonstrated good kinome selectivity with good overall drug-like properties for oral dosing, was well tolerated across preclinical species at pharmacologically relevant doses with good ADME properties, and achieved >90% inhibition of BTK phosphorylation (pBTK) in humans.

Micro RNA (miRNA) and its regulatory effect on messenger RNA (mRNA) gene expression are a major focus in cancer research. Disruption in the normal miRNA-mRNA regulation network can result in serious cascading biological repercussions. In this study, we curated miRNA-related variants from major genomic consortiums and thoroughly evaluated how these variants could exert their effects by cross-validating with independent functional knowledge bases. Nearly all known variants (more than 664 million) categorized by type (germline, somatic, epigenetic) were mapped to the genomic regions involved in miRNA-mRNA binding (miRNA seeds and miRNA-mRNA 3'-UTR binding sequence). Subsets of miRNA-related variants supported by additional functional evidence, such as expression Quantitative Trait Loci (eQTL) and Genome-Wide Association Study (GWAS), were identified and scrutinized. Our results show that variants in miRNA seeds can substantially alter the composition of a miRNA's target mRNA set. Various functional analyses converged to reveal a post-transcriptional complex regulatory network where miRNA, eQTL, and RNA-binding protein intertwined to disseminate the impact of genomic variants. These results may potentially explain how certain variants affect disease/trait risks in genome wide association studies.

Background: Cancer has been disproportionally affecting minorities in the US due to socioeconomic, environmental, and genetic disparities. Cancer disparities are usually measured in incidence, mortality, survival, etc. Genomic-based cancer disparity analyses have been less common. In the past decade, mutational signatures were proposed as characteristic footprints of endogenous or exogenous carcinogens, which remarkably propelled the progress of genomic cancer research. The disparities caused by uneven exposure to environmental pollutants may be recorded in mutational signatures. Method: The Cancer Genome Altas is one of the richest genomic cancer datasets, empowering hundreds of secondary and tertiary cancer studies. One aspect of TCGA data that is seldomly utilized is geospatial information. Based on the contribution hospital location, we estimated the patients’ approximate location. Furthermore, utilizing data on 450 pollutants released by the Environmental Protection Agency from 2007-2017, we were able to establish associations between mutational signatures and certain pollutants. To remove the noise introduced by approximating the location and average pollution level, stringent statistical procedures were applied. Results: First, we showed that mutation frequencies varied substantially between different races. For example, TP53 was mutated in 46% of Black breast cancer patients, compared to 31% in Whites. Such differences in single genes translated to the level of mutational signatures. Liver cancer has aflatoxin as an affirmed carcinogen, and we compared the quantities of aflatoxin signature across races. It was found that aflatoxin contributed significantly higher (FDR = 0.002) to mutations in Asian than in Caucasians. In-depth analyses revealed that aflatoxin had a strong effect on hepatitis C virus infection in addition to the previously reported effect on hepatitis B virus infection. Similarly, as a known critical player in head and neck tumors, APOBEC signature was found at a significantly higher level (FDR = 0.01) in patients with positive infection of human papillomavirus. Furthermore, analyses from the geospatial perspective revealed several potential associations between pollutants and mutational signatures. For example, the pollutant carbofuran is positively associated with mutational signature SBS10a with the etiology of Polymerase epsilon exonuclease domain mutations (FDR = 0.02). Summary: We conducted a thorough mutational signature-based cancer disparity analysis. Our results reinforced previously known facts and expectations of oncogene mutations. The novel results demonstrated representative links between various forms of cancer disparity and genomic mutation footprints. Most importantly, such disparities can be interrogated at the mutational signature level and correlated to environmental pollutants. Citation Format: Yan Guo, Judy Bai, Katherine Ma, Shangyang Xia, Shuguang Leng, Hui Yu, Xi Gong. Cancer disparities in race exposed through geospatial analysis of mutational signatures and environmental exposure [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3505.