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Biology subjects

Adil, M.

Publications and source records attributed to Adil, M..

6 recordsLinked to original sources

Evidence that the protein phosphatase activity of PTEN contributes to embryonic development and tumour suppression in mice

PTEN (phosphatase and tensin homologue deleted on chromosome ten) is a tumour suppressor, the function of which is impaired in many diverse cancers. It has phosphoinositide lipid phosphatase activity by which it suppresses activation of the oncogenic PI3K signalling network but in vitro also displays activity against protein substrates and is able to auto-dephosphorylate its Thr366 residue. Here we generate germline knock-in mice expressing PTEN-Y138L, a mutant enzyme which selectively lacks protein phosphatase activity and retains lipid phosphatase activity. Homozygous PtenY138L/Y138L mice die in utero before E10.5. Primary MEFs and thymocytes with only a single PtenY138L allele display normal low levels of AKT phosphorylation indicating effective regulation of PI3K signalling by endogenous PTEN-Y138L in vivo. Heterozygous Pten+/Y138L mice have reduced overall survival compared to wild type littermates and develop tumours in multiple organs. Our data imply that in addition to its lipid phosphatase activity, the protein phosphatase activity of PTEN is also required for normal embryonic development and tumour suppression.

cancer biology↗

Deep learning-based non-invasive profiling of tumor transcriptomes from cell-free DNA for precision oncology

Tumor gene expression profiling provides crucial diagnostic information for guiding therapy, but standard tissue biopsies are invasive, spatially biased, and may inadequately sample metastatic disease. Cell-free DNA (cfDNA) provides a minimally invasive alternative for tumor genotyping, yet reconstructing robust, transcriptome-wide expression from standard-depth cfDNA whole-genome sequencing (WGS) remains a major challenge. We developed a deep learning framework comprising Triton, for comprehensive cfDNA feature extraction, and Proteus, a probabilistic model that infers single-gene expression from standard-depth cfDNA WGS. Proteus outperformed prior cfDNA approaches in reconstructing molecular phenotypes from matched tumor transcriptomes across multiple cancer types, including prostate, lung, and bladder cancer cohorts, with uncertainty-guided withholding improving model reliability. Proteus further enabled assessment of therapeutic target activity, prognostic transcriptional programs, and candidate treatment-emergent resistance states, establishing a generalizable framework for minimally invasive functional genomics in precision oncology.

bioinformatics↗

A mouse model of PTEN Hamartoma Tumour Syndrome reveals that loss of the nuclear function of PTEN drives macrocephaly, lymphoid overgrowth, and late-onset cancer

PTEN Hamartoma Tumour Syndrome (PHTS) is a rare disorder characterized by germline heterozygous mutations in the PTEN tumour suppressor gene, leading to multi-organ/tissue overgrowth, autism spectrum disorder and increased cancer risk. PHTS individuals display heterogeneity in phenotypes, which has been linked in part to the diverse genetic alterations in the PTEN gene and the multifaceted functions of this protein. Indeed, while PTEN primarily functions as a PIP3 lipid phosphatase in the cytosol, regulating PI3K/AKT signalling, a pathway commonly deregulated in cancer, it also plays crucial roles in maintaining chromosomal stability through nuclear activities such as double strand (ds) DNA damage repair. Recent studies have identified a subset of missense PHTS variants that cause nuclear exclusion of PTEN, impairing its nuclear functions. Here, we present our findings from one such pathogenic variant, PTEN-R173C, frequently found in PHTS and somatic cancers. Using cell biological and mouse modelling approaches, we show that PTEN-R173C has higher PIP3 phosphatase activity than wild-type PTEN, resulting in effective regulation of canonical PI3K/AKT signalling. However, PTEN-R173C is unstable and excluded from the nucleus. Aligning with their near normal PI3K/AKT signalling, Pten+/R173Cmice display a low incidence of solid tumours compared to Pten+/-mice. Pten+/R173C mice also exhibit lymphoid hyperplasia and macrocephaly which correlates with compromised nuclear functions of PTEN-R173C. That nuclear functions are compromised is demonstrated by reduced dsDNA damage repair in Pten+/R173Cmice. Integrating PHTS patient data with findings from our mouse model, our study indicates that nuclear dysfunction of pathogenic PTEN variants is a key factor in predicting the onset of the different PHTS-associated phenotypes. We speculate that late-onset cancer in individuals with nuclear-excluded PTEN results from genetic alterations unrelated to PTEN itself, facilitated by impaired PTEN-mediated dsDNA damage repair.

genetics↗

Nucleosome patterns in circulating tumor DNA reveal transcriptional regulation of advanced prostate cancer phenotypes

Advanced prostate cancers comprise distinct phenotypes, but tumor classification remains clinically challenging. Here, we harnessed circulating tumor DNA (ctDNA) to study tumor phenotypes by ascertaining nucleosome positioning patterns associated with transcription regulation. We sequenced plasma ctDNA whole genomes from patient-derived xenografts representing a spectrum of androgen receptor active (ARPC) and neuroendocrine (NEPC) prostate cancers. Nucleosome patterns associated with transcriptional activity were reflected in ctDNA at regions of genes, promoters, histone modifications, transcription factor binding, and accessible chromatin. We identified the activity of key phenotype-defining transcriptional regulators from ctDNA, including AR, ASCL1, HOXB13, HNF4G, and NR3C1. Using these features, we designed a prediction model which distinguished NEPC from ARPC in patient plasma samples across three clinical cohorts with 97-100% sensitivity and 85-100% specificity. While phenotype classification is typically assessed by immunohistochemistry or transcriptome profiling, we demonstrate that ctDNA provides comparable results with numerous diagnostic advantages for precision oncology. STATEMENT OF SIGNIFICANCEThis study provides key insights into the dynamics of nucleosome positioning and gene regulation associated with cancer phenotypes that can be ascertained from ctDNA. The new methods established for phenotype classification extend the utility of ctDNA beyond assessments of DNA alterations with important implications for molecular diagnostics and precision oncology.

cancer biology↗

Multi-omic Characterization of Human Tubular Epithelial Cell Response to Serum

Proteinuria, the spillage of serum proteins into the urine, is a feature of glomerulonephritides, podocyte disorders and diabetic nephropathy. However, the response of tubular epithelial cells to serum protein exposure has not been systematically characterized. Using transcriptomic profiling we studied serum-induced changes in primary human tubular epithelial cells cultured in 3D microphysiological devices. Serum proteins induced cellular proliferation, cytokine secretion and activated a coordinated stress response. We orthogonally confirmed our findings by comparing the transcriptomic and epigenomic landscapes of intact human kidney cortex and isolated tubular epithelial cells cultured in fetal bovine serum. Importantly, key transcriptomic programs in response to either type of serum exposure remained consistent, including comparisons to an established mouse model of kidney injury. This serum-induced transcriptional response was dominated by switching off of nuclear receptor-driven programs and activation of AP-1 and NF-{kappa}B signatures in the tubular epigenomic landscape. These features of active regulation were seen at canonical kidney injury genes (HAVCR1) and genes associated with COVID-19 (ACE2, IL6). Our data provide a reference map for dissecting the regulatory and transcriptional response of kidney tubular epithelial cells injury induced by serum.

cell biology↗

Towards the human cellular microRNAome

microRNAs are short RNAs that serve as master regulators of gene expression and are essential components of normal development as well as modulators of disease. MicroRNAs generally act cell autonomously and thus their localization to specific cell types is needed to guide our understanding of microRNA activity. Current tissue-level data has caused considerable confusion and comprehensive cell-level data does not yet exist. Here we establish the landscape of human cell-specific microRNA expression. This project evaluated 8 billion small RNA-seq reads from 46 primary cell types, 42 cancer or immortalized cell lines, and 26 tissues. It identified both specific and ubiquitous patterns of expression that strongly correlate with adjacent super-enhancer activity. Analysis of unaligned RNA reads uncovered 207 unknown minor strand (passenger) microRNAs of known microRNA loci and 2,632 novel putative microRNA loci. Although cancer cell lines generally recapitulated the expression patterns of matched primary cells, their isomiR sequence families exhibited increased disorder suggesting Drosha and Dicer-dependent microRNA processing variability. Cell-specific patterns of microRNA expression were used to deconvolute variable cellular composition of adipose tissue samples highlighting one use of this cell-specific microRNA expression data. Characterization of cellular microRNA expression across a wide variety of cell types provides a new understanding of this critical regulatory RNA species.

genomics↗