Biology subjects

Chatila, W.

Publications and source records attributed to Chatila, W..

3 recordsLinked to original sources

bioRxiv2026

SMARCA4, STK11, and KEAP1 co-inactivation associates with poor prognosis and upregulation of the TGF-β pathway in lung adenocarcinoma

BackgroundLung adenocarcinoma (LUAD) is clinically and molecularly defined by oncogenic driver mutations, identification of which has led to the development of driver-targeted therapies and substantial improvements in prognosis for subsets of LUAD patients. Recent studies assessing clinical outcomes in the context of multigenic alterations have identified secondary mutations that might explain differential responses to targeted therapies, chemotherapies and immunotherapies. Genetic inactivation or loss of SMARCA4, which frequently co-occurs with loss-of-function mutations in STK11 and KEAP1, is especially predictive of poor prognosis and shorter overall survival in LUAD patients, regardless of driver status. We sought to examine the clinical and functional associations of SMARCA4 deficiency in LUAD, with or without co-associated STK11/KEAP1 loss-of-function. MethodsWe examined correlation between SMARCA4 loss, gene expression and prognosis through genomic and transcriptomic profiling of clinically annotated LUAD samples. We generated isogenic cell line models with genetic knockouts of SMARCA4 with or without concomitant STK11 and KEAP1 to profile mutationally-defined genotypes of interest in vitro and in vivo. Lastly, we interrogated the functional dependency of SMARCA4/STK11/KEAP1 triple mutant models on TGF-{beta} signaling to assess its potential as a therapeutic target. ResultsSMARCA4/STK11/KEAP1 triple mutant LUAD is associated with poor survival and high frequency of multisite metastasis. SMARCA4/STK11/KEAP1 triple knockout models showed enhanced migration and invasion in vitro, and diversified organotropism in an in vivo intracardiac xenograft metastasis assay. RNA-Seq and DNaseI-Seq of these in vitro models and clinical samples identified upregulation of TGF-{beta} signaling and EMT gene expression signatures, and corresponding changes in chromatin accessibility, in SMARCA4/STK11/KEAP1 triple mutant LUAD. ConclusionsWe identify SMARCA4/STK11/KEAP1 triple mutant LUAD as a prognostically significant disease subset and nominate TGF-{beta} signaling as a potential therapeutic target.

cancer biology↗

bioRxiv2023

Distinct tumor architectures for metastatic colonization of the brain

Brain metastasis is a dismal cancer complication, hinging on the initial survival and outgrowth of disseminated cancer cells. To understand these crucial early stages of colonization, we investigated two prevalent sources of cerebral relapse, triple-negative (TNBC) and HER2+ breast cancer (HER2BC). We show that these tumor types colonize the brain aggressively, yet with distinct tumor architectures, stromal interfaces, and autocrine growth programs. TNBC forms perivascular sheaths with diffusive contact with astrocytes and microglia. In contrast, HER2BC forms compact spheroids prompted by autonomous extracellular matrix components and segregating stromal cells to their periphery. Single-cell transcriptomic dissection reveals canonical Alzheimers disease-associated microglia (DAM) responses. Differential engagement of tumor-DAM signaling through the receptor AXL suggests specific pro-metastatic functions of the tumor architecture in both TNBC perivascular and HER2BC spheroidal colonies. The distinct spatial features of these two highly efficient modes of brain colonization have relevance for leveraging the stroma to treat brain metastasis.

cancer biology↗

bioRxiv2022

Oncogenic IDH mutations increase heterochromatin-related replication stress without impacting tumor mutation burden

Oncogenic mutations in the metabolic enzyme isocitrate dehydrogenase 1 and 2 (IDH1/2) have been found in a number of liquid and solid tumors. Their pathogenic mechanism of action involves production of 2-hydroxyglutarate (2HG), an oncometabolite that acts in part by inhibiting members of a family of dioxygenases that modulate chromatin dynamics. Recent work has suggested that mutant IDH (mIDH) and 2HG also impact sensitivity to inhibitors of poly-ADP ribose polymerases (PARP) but the molecular basis for this sensitivity is unclear. Unlike PARP inhibitor-sensitive BRCA1/2 tumors which exhibit impaired homologous recombination, IDH-mutant tumors have a silent mutational profile and lack mutational signatures associated with impaired homologous recombination. Instead, 2HG-producing IDH mutations lead to heterochromatin-dependent slowing of DNA replication and increased replication stress, resulting in DNA double strand breaks. This replicative stress manifests as replication fork slowing but the breaks are repaired without a significant increase in the cellular mutation burden. Faithful resolution of replicative stress in IDH-mutant cells is dependent on poly-ADP ribosylation. Treatment with PARP inhibitors restores replication fork speed but results in incomplete repair of DNA breaks. These findings provide evidence of a requirement for PARP in the replication of heterochromatin and further validate PARP as a potential therapeutic target in IDH-mutant tumors.

cancer biology↗