Biology subjects

Thirmanne, H. N.

Publications and source records attributed to Thirmanne, H. N..

4 recordsLinked to original sources

bioRxiv2026

Beyond Histology: A Unified Transcriptomic Atlas Defines Lung Cancer Biologic States and Subtypes

Lung cancer encompasses multiple histological entities with substantial molecular heterogeneity that remain incompletely resolved at population scale. Here, we constructed a unified reference landscape of lung cancer by analyzing raw RNA sequencing data from 1,824 tumors spanning adenocarcinoma (n=966), squamous cell carcinoma (n=628), small cell lung cancer (n=150), and unclassified non small cell lung cancer (n=80). Following batch correction, samples were analyzed using consensus clustering and visualized with PaCMAP to generate a molecular atlas annotated with clinical and biological metadata. Rather than segregating by pathological diagnosis, tumors organized along conserved transcriptional axes defined by tumor-intrinsic biology including proliferative or metabolic programs and immune-infiltrated states. Consensus clustering resolved nine robust molecular clusters, including an adenocarcinoma-associated subgroup, a neuroendocrine-like adenocarcinoma marked by ASCL1 activation, immune-associated regions, and bifurcation of both small cell and squamous carcinomas into biologically distinct states. Spatially restricted expression of selected clinically relevant transcripts nominated state-specific therapeutic hypotheses requiring future functional and clinical validation. Projection of patient tumors and patient-derived xenografts onto the atlas demonstrated preservation of transcriptional identity and enabled quantitative assessment of model fidelity. This integrated framework organizes lung cancer as a structured continuum of transcriptional states and provides a reference resource for biological interpretation and future translational studies.

bioinformatics↗

bioRxiv2025

PTEN deficiency linked to chromosome 10q loss leads to aggressive NF2mutant meningioma biology

While most meningiomas are benign and can be surgically removed, a subset behaves aggressively, recurs quickly, and can ultimately be fatal. Recent work has focused on defining this aggressive group. To better characterize this clinically distinct, high-risk group, we analyzed bulk RNA sequencing (RNA-seq) from human meningiomas using a dimension-reduced reference landscape. We identified an NF2 mutant subtype enriched for chromosome 10q loss and low PTEN expression, both of which were strongly associated with shorter time to recurrence. To directly test causality, we engineered several genetically accurate, immunocompetent in vitro and in vivo mouse models with Pten knockdown or knockout. Across models, Pten loss markedly accelerated YAP1-driven tumorigenesis. Projection of Pten-deficient mouse tumors onto bulk and single-cell RNA-seq datasets from human meningiomas revealed that mouse tumors faithfully recapitulate the transcriptional programs of aggressive NF2 mutant meningiomas and robustly predicted clinical outcomes. Collectively, these findings demonstrate that PTEN loss cooperates with YAP1 activation to drive aggressive NF2 mutant meningioma biology, and that the high fidelity of this model to human disease establishes it as a robust platform for mechanistic investigation and therapeutic testing. More broadly, this work highlights the power of cross-species integration in both validating preclinical models and enhancing the translational relevance and utility of dimension-reduced reference landscapes across diverse disease types. One Sentence SummaryPTEN loss causally drives aggressive NF2 mutant meningiomas, and cross-species integration provides a novel, high-fidelity system to validate preclinical models to human disease.

cancer biology↗

bioRxiv2024

Aggressive high-grade NF2 mutant meningiomas downregulate oncogenic YAP signaling via the upregulation of VGLL4 and FAT3/4.

Meningiomas are the most common primary brain tumors in adults. Although generally benign, a subset of meningiomas is of higher grade, shows aggressive growth behavior and recurs even after multiple surgeries. Around half of all meningiomas harbor inactivating mutations in NF2. While benign low-grade NF2 mutant meningiomas exhibit few genetic events in addition to NF2 inactivation, aggressive high-grade NF2 mutant meningiomas frequently harbor a highly aberrant genome. We and others have previously shown that NF2 inactivation leads to YAP1 activation and that YAP1 acts as the pivotal oncogenic driver in benign NF2 mutant meningiomas. Using bulk and single-cell RNA-Seq data from a large cohort of human meningiomas, we show that aggressive NF2 mutant meningiomas harbor decreased levels YAP1 activity compared to their benign counterparts. Decreased expression levels of YAP target genes are significantly associated with an increased risk of recurrence. We then identify the increased expression of the YAP1 competitor VGLL4 as well as the YAP1 upstream regulators FAT3/4 as a potential mechanism for the downregulation of YAP activity in aggressive NF2 mutant meningiomas. High expression of these genes is significantly associated with an increased risk of recurrence. In vitro, overexpression of VGLL4 resulted in the downregulation of YAP activity in benign NF2 mutant meningioma cells, confirming the direct link between VGLL4 expression and decreased levels of YAP activity observed in aggressive NF2 mutant meningiomas. Our results shed new insight on the biology of benign and aggressive NF2 mutant meningiomas and may have important implications for the efficacy of therapies targeting oncogenic YAP1 activity in NF2 mutant meningiomas.

molecular biology↗

bioRxiv2021

Global and context-specific transcriptional consequences of oncogenic Fbw7 mutations

Fbw7 is a ubiquitin ligase substrate receptor that targets proteins for proteasomal degradation. Most known Fbw7 substrates are transcription factors (TFs) and many are also oncoproteins (e.g., c-Myc, c-Jun, Notch). Fbw7 is an important tumor suppressor and FBXW7 mutations drive tumorigenesis through activation of oncogenic Fbw7 substrates. Defining the mechanisms of Fbw7-associated tumorigenesis is critical for developing targeted therapies. We thus determined the transcriptional consequences of oncogenic Fbw7 mutations by studying isogenic colorectal cancer cell lines with engineered FBXW7 null and heterozygous missense mutations. We used an integrated approach employing RNA-Seq and high-resolution mapping (CUT&RUN) of histone modifications and TF occupancy (c-Jun and c-Myc) to examine the combinatorial effects of mis-regulated Fbw7 substrates. Fbw7 mutations caused widespread transcriptional changes associated with active chromatin and altered TF occupancy at distal regulatory regions. Some regulatory changes were common to both FBXW7-mutant cell lines whereas others were FBXW7 mutation-specific. By comparing c-Jun and c-Myc binding sites, we also identified co-regulated elements, suggesting that Fbw7 substrates may have synergistic effects. One co-regulated gene was CIITA, a master regulator of MHC Class II gene expression, and Fbw7 loss increased CIITA and MHC Class II gene expression in colorectal cancer cells. Fbw7 mutations were also correlated with increased CIITA expression in TCGA colorectal tumors and cell lines, which may have immunologic implications for progression and treatment of Fbw7-associated cancers. This integrative analysis provides a framework for understanding normal and neoplastic context-specific Fbw7 functions.

cancer biology↗