Biology subjects

Lipkin, S.

Publications and source records attributed to Lipkin, S..

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↗

bioRxiv2022

Neuron- and microglial specific immunoexpression in steroid-independent male sexual behaviour in castrated B6D2F1 male mice

Sexual behaviour is necessary for procreation for several species and is traditionally viewed to be regulated by sex steroid hormones. However, several species exhibit steroid-independent sexual behaviour, and its molecular understanding is only beginning to be uncovered. The main goal of our experiment was to provide new insight into cell-specific roles that both neuronal and non-neuronal cells may play in steroid-independent male sexual behaviour. Forty B6D2F1 hybrid male mice underwent orchidectomy and were tested for reinstatement of steroid-independent male sexual behaviour after an extended period of social isolation caused by the COVID-19-mandated laboratory shutdown. After 62 weeks post-orchidectomy, 20.59% demonstrated reinstatement of steroid-independent male sexual behaviour (identified as steroid-independent persistent maters), while 23.53% of the males did not display steroid-independent male sexual behaviour (identified as steroid-independent non-maters). Using flow cytometry, we compared the preoptic area immunoexpression in NeuN+ neurons and Iba1+ microglia between steroid-independent persistent maters and steroid-independent non-maters (N = 5-6 per group). We found neuronal immunoexpression up-regulated for amyloid precursor protein and androgen receptor, as well as down-regulated for glucocorticoid receptor in steroid-independent persistent maters compared to steroid-independent non-maters. In conjunction, microglial immunoexpression of amyloid precursor protein was up-regulated in steroid-independent persistent maters compared to steroid-independent non-maters. These data suggest there are cell-specific immunoexpression differences, including the role of non-neuronal cells in steroid-independent male sexual behaviour.

neuroscience↗

bioRxiv2018

Towards automation of germline variant curation inclinical cancer genetics

Cancer care professionals are confronted with interpreting results from multiplexed gene sequencing of patients at hereditary risk for cancer. Assessments for variant classification now require orthogonal data searches, requiring aggregation of multiple lines of evidence from diverse resources. The burden of evidence for each variant to meet thresholds for pathogenicity or actionability now poses a growing challenge for those seeking to counsel patients and families following germline genetic testing. A computational algorithm that automates, provides uniformity and significantly accelerates this interpretive process is needed. The tool described here, Pathogenicity of Mutation Analyzer (PathoMAN) automates germline genomic variant curation from clinical sequencing based on ACMG guidelines. PathoMAN aggregates multiple tracks of genomic, protein and disease specific information from public sources. We compared expert manually curated variant data from studies on (i) prostate cancer (ii) breast cancer and (iii) ClinVar to assess performance. PathoMAN achieves high concordance (83.1% pathogenic, 75.5% benign) and negligible discordance (0.04% pathogenic, 0.9% benign) when contrasted against expert curation. Some loss of resolution (8.6% pathogenic, 23.64% benign) and gain of resolution (6.6% pathogenic, 1.6% benign) was also observed. We highlight the advantages and weaknesses related to the programmable automation of variant classification. We also propose a new nosology for the five ACMG classes to facilitate more accurate reporting to ClinVar. The proposed refinements will enhance utility of ClinVar to allow further automation in cancer genetics. PathoMAN will reduce the manual workload of domain level experts. It provides a substantial advance in rapid classification of genetic variants by generating robust models using a knowledge-base of diverse genetic data https://pathoman.mskcc.org.

genetics↗

bioRxiv2017

High-depth whole genome sequencing of a large population-specific reference panel: Enhancing sensitivity, accuracy, and imputation

BackgroundWhile increasingly large reference panels for genome-wide imputation have been recently made available, the degree to which imputation accuracy can be enhanced by population-specific reference panels remains an open question. In the present study, we sequenced at full-depth ([≥]30x) a moderately large (n=738) cohort of samples drawn from the Ashkenazi Jewish population across two platforms (Illumina X Ten and Complete Genomics, Inc.). We developed and refined a series of quality control steps to optimize sensitivity, specificity, and comprehensiveness of variant calls in the reference panel, and then tested the accuracy of imputation against target cohorts drawn from the same population.\n\nResultsFor samples sequenced on the Illumina X Ten platform, quality thresholds were identified that permitted highly accurate calling of single nucleotide variants across 94% of the genome. The Complete Genomics, Inc. platform was more conservative (fewer variants called) compared to the Illumina platform, but also demonstrated relatively greater numbers of false positives that needed to be filtered. Quality control procedures also permitted detection of novel genome reads that are not mapped to current reference or alternate assemblies. After stringent quality control, the population-specific reference panel produced more accurate and comprehensive imputation results relative to publicly available, large cosmopolitan reference panels. The population-specific reference panel also permitted enhanced filtering of clinically irrelevant variants from personal genomes.\n\nConclusionsOur primary results demonstrate enhanced accuracy of a population-specific imputation panel relative to cosmopolitan panels, especially in the range of infrequent (<5% non-reference allele frequency) and rare (<1% non-reference allele frequency) variants that may be most critical to further progress in mapping of complex phenotypes.

genomics↗

bioRxiv2017

A Strategy for Large-Scale Systematic Pan-Cancer Germline Rare Variation Analysis

Traditionally, genetic studies in cancer are focused on somatic mutations found in tumors and absent from the normal tissue. Identification of shared attributes in germline variation could aid discrimination of high-risk from likely benign mutations and narrow the search space for new cancer predisposing genes. Extraordinary progress made in analysis of common variation with GWAS methodology does not provide sufficient resolution to understand rare variation. To fulfil missing classification for rare germline variation we assembled datasets of whole exome sequences from >2,000 patients with different types of cancers: breast cancer, colon cancer and cutaneous and ocular melanomas matched to more than 7,000 non-cancer controls and analyzed germline variation in known cancer predisposing genes to identify common properties of disease associated mutations and new candidate cancer susceptibility genes. Lists of all cancer predisposing genes were divided into subclasses according to the mode of inheritance of the related cancer syndrome or contribution to known major cancer pathways. Out of all subclasses only genes linked to dominant syndromes presented significant rare germline variants enrichment in cases. Separate analysis of protein-truncating and missense variation in this subclass of genes confirmed significant prevalence of protein-truncating variants in cases only in loss-of-function tolerant genes (pLI<0.1), while ultra-rare missense mutations were significantly overrepresented in cases only in constrained genes (pLI>0.9). Taken together, our findings provide insights into the distribution and types of mutations underlying inherited cancer predisposition.

genetics↗