Biology subjects

Carrot-Zhang, J.

Publications and source records attributed to Carrot-Zhang, J..

5 recordsLinked to original sources

bioRxiv2026

SLC25A28 is a synthetic lethal vulnerability in nucleotide excision repair-deficient cancers

Approximately 10% of bladder, upper urinary tract, and endometrial cancers harbor deleterious somatic alterations in nucleotide excision repair (NER) pathway genes. Although platinum-based chemotherapy is the standard treatment for NER-deficient tumors, its utility is limited by nephrotoxicity, motivating alternative strategies that avoid direct DNA targeting. Here, we employed a genome-wide CRISPR-Cas9 screen to identify synthetic lethal vulnerabilities in NER-deficient cancer cells. An ERCC4-null RT112/84 bladder cancer cell line was generated and validated by Sanger sequencing and Western blotting, and functional NER deficiency was confirmed using a host cell reactivation assay. Parallel screens in ERCC4-deficient and isogenic wild-type cells. nominated SLC25A28 as the top-ranked synthetic lethal candidate in ERCC4-deficient cells, an interaction further supported by DepMap dependency. Clonogenic assays confirmed that loss of SLC25A28 selectively impaired cell viability in cells deficient for ERCC2, ERCC3, ERCC4, or ERCC5 and inducible knockout selectively suppressed ERCC4-deficient xenograft growth in-vivo. Mechanistically, RNA sequencing followed by gene set enrichment analysis revealed enrichment of oxidative stress-related pathways, including cellular responses to reactive oxygen species (ROS) and DNA damage signatures, upon SLC25A28 loss. These transcriptional changes are consistent with increased oxidative stress and DNA damage, placing heightened demand on NER-mediated repair. Direct measurement confirmed increased intracellular ROS. Collectively, our nominates SLC25A28 as a previously unrecognized synthetic lethal vulnerability in NER-deficient cancers and implicate mitochondrial iron homeostasis as a candidate metabolic dependency that may be targeted independently of platinum-based chemotherapy.

cancer biology↗

bioRxiv2023

Dynamic clustering of genomics cohorts beyond race, ethnicity--and ancestry

BackgroundRecent decades have witnessed a steady decrease in the use of race categories in genomic studies. While studies that still include race categories vary in goal and type, these categories already build on a history during which racial color lines have been enforced and adjusted in the service of social and political systems of power and disenfranchisement. For early modern biological classification systems, data collection was also considerably arbitrary and limited. Fixed, discrete classifications have limited the study of human biodiversity and disrupted widely spread genetic and phenotypic continuums across geographic scales. Relatedly, the use of broad and predefined classification schemes--e.g. continent-based--across traits can risk missing important trait-specific genomic signals. ResultsTo address these issues, we introduce a dynamic approach to clustering human genomics cohorts on a trait-specific level and without using a set of predefined categories. We tested the approach on whole-exome sequencing datasets in ten cancer types and partitioned them based on germline variants in cancer-relevant genes that could confer cancer type-specific disease predisposition. Results demonstrate clustering patterns that transcend discrete continent-based categories across cancer types. Functional analysis based on cancer type-specific clusterings also captures the fundamental biological processes underlying cancer, differentiates between dynamic clusters on a functional level, and identifies novel potential drivers overlooked by a continent-based clustering model. ConclusionsThrough a trait-based lens, the dynamic clustering approach reveals genomic patterns that transcend predefined classification categories. We propose that coupled with diverse data collection, new clustering approaches have the potential to draw a more complete portrait of genomic variation and to address, in parallel, technical and social aspects of studying human biodiversity.

genomics↗

bioRxiv2022

Patterns of Structural Variation Define Prostate Cancer Across Disease States

The complex genomic landscape of prostate cancer evolves across disease states under therapeutic pressure directed toward inhibiting androgen receptor (AR) signaling. While significantly altered genes in prostate cancer have been extensively defined, there have been fewer systematic analyses of how structural variation shapes the genomic landscape of this disease across disease states. We uniformly characterized structural alterations across 278 localized and 143 metastatic prostate cancers profiled by whole genome and transcriptome sequencing. We observed distinct significantly recurrent breakpoints in localized and metastatic castration-resistant prostate cancers (mCRPC), with pervasive alterations in noncoding regions flanking the AR, MYC, FOXA1, and LSAMP genes enriched in mCRPC and TMPRSS2-ERG rearrangements enriched in localized prostate cancer. We defined nine subclasses of mCRPC based on signatures of structural variation, each associated with distinct genetic features and clinical outcomes. Our results comprehensively define patterns of structural variation in prostate cancer and identify clinically actionable subgroups based on whole genome profiling.

genomics↗

bioRxiv2021

Germline Missense Variants in CDC20 Result in Aberrant Mitotic Progression and Familial Cancer

CDC20 is a co-activator of the anaphase promoting complex/cyclosome (APC/C) and is essential for mitotic progression. APC/CCDC20 is inhibited by the spindle assembly checkpoint (SAC), which prevents premature separation of sister chromatids and aneuploidy in daughter cells. Although overexpression of CDC20 is common in many cancers, oncogenic mutations have never been identified in humans. Using whole exome sequencing, we identified heterozygous missense CDC20 variants (L151R and N331K) that segregate with cancer in two families. Characterization of these mutants showed they retain APC/C activation activity but show reduced binding to BUBR1, a component of the SAC. Expression of L151R and N331K promoted mitotic slippage in HeLa cells and primary skin fibroblasts derived from carriers. CRISPR/Cas9 was used to generate mice carrying N331K. Homozygous mice carrying N331K were non-viable, however, heterozygotes displayed accelerated oncogenicity in Myc-driven cancers. These findings highlight an unappreciated role for CDC20 variants as tumor promoting genes in humans.

cancer biology↗

bioRxiv2021

Combined tumor and immune signals from genomes or transcriptomes predict outcomes of checkpoint inhibition in melanoma

Cancer immunotherapy with checkpoint blockade (CPB) leads to improved outcomes in melanoma and other tumor types, but a majority of patients do not respond. High tumor mutation burden (TMB) and high levels of tumor-infiltrating T cells have been associated with response to immunotherapy, but integrative models to predict clinical benefit using DNA or RNA alone have not been comprehensively explored. We sequenced DNA and RNA from melanoma patients receiving CPB, and aggregated previously published data, yielding whole exome sequencing data for 189 patients and bulk RNA sequencing data for 178 patients. Using these datasets, we derived genomic and transcriptomic factors that predict overall survival (OS) and response to immunotherapy. Using whole-exome DNA data alone, we calculated T cell burden (TCB) and B cell burden (BCB) based on rearranged TCR/Ig DNA sequences and found that patients whose melanomas have high TMB together with either high TCB or high BCB survived longer and had higher response rates as compared to patients with either low TMB or TCB/BCB. Next, using bulk RNA-Seq data, differential expression analysis identified 83 genes associated with high or low OS. By combining pairs of immune-expressed genes with tumor-expressed genes, we identified three gene pairs associated with response and survival (Bonferroni P<0.05). All three gene pair models were validated in an independent cohort (n=180) (Bonferroni P<0.05). The best performing gene pair model included the lymphocyte-expressed MAP4K1 (Mitogen- Activated Protein Kinase Kinase Kinase Kinase 1) combined with the transcription factor TBX3 (T-Box Transcription Factor 3) which is overexpressed in poorly differentiated melanomas. We conclude that RNA-based (MAP4K1&TBX3) or DNA-based (TCB&TMB) models combining immune and tumor measures improve predictions of outcome after checkpoint blockade in melanoma.

genomics↗