Abstract PR006: ARID1A/B mutations retarget mSWI/SNF chromatin remodeler activity and define a spectrum of dedifferentiation in endometrial carcinoma
Bibliographic record
Abstract
Abstract Dedifferentiated/undifferentiated endometrial carcinoma (DEC/UEC) is a highly aggressive histologic subtype of uterine cancer with a higher incidence among non-Hispanic Black women. Recent exome-wide sequencing studies have revealed frequent and often concomitant mutations in the ARID1A and ARID1B genes in over 50% of DEC/UEC cases and 30% of all endometrial carcinomas. The mSWI/SNF family of chromatin remodelers are critical regulators of cell type-specific chromatin accessibility and gene expression, existing in three distinct forms: canonical BAF (cBAF), Poly bromodomain-associated BAF (PBAF), and non-canonical BAF (ncBAF). The paralog subunits, ARID1A and ARID1B, specifically nucleate the assembly of cBAF complexes. However, the precise role ARID1A/ARID1B mutations (cBAF loss) play in the development of dedifferentiated endometrial carcinoma remains unclear. In this study, we define an expression signature associated with endometrial “dedifferentiation” by profiling the well-differentiated and dedifferentiated components of cBAF loss DEC cases through laser capture microdissection followed by RNA sequencing. Introduction of ARID1A or ARID1B in cBAF loss DEC cell lines demonstrated the restoration of cBAF assembly, confirmed by glycerol gradient and IP mass spectrometry. Upon the expression of ARID1A or ARID1B, we observed widespread chromatin occupancy and DNA accessibility at distinct paralog-specific sites, along with common sites associated with epithelial lineage differentiation, estrogen receptor, and PI3K/AKT pathway signaling. These findings align with the differentiation signature, defined in DEC cases demonstrating downregulation of genes associated with Myc targets, cell cycle checkpoint pathways, and DNA repair, suggesting these pathways represent potential therapeutic avenues for targeting DEC/UEC. Collectively, these data establish that well-differentiated endometrial carcinoma and DEC/UEC with mSWI/SNF mutations represent a spectrum of cBAF loss, defining the unique roles of ARID1A and ARID1B in endometrial carcinoma development. Furthermore, these findings imply that cBAF loss drives the widespread changes in DEC morphology, gene expression, and clinical behavior, enhancing our understanding of the etiology and therapeutic options for these cancers. Citation Format: Jessica D. St. Laurent, Grace Xu, Kasey Cervantas, Ajinkya Patil, Akshay Sankar, Shary Chen, David Kolin, Yemin Wang, David G. Huntsman, Cigall Kadoch. ARID1A/B mutations retarget mSWI/SNF chromatin remodeler activity and define a spectrum of dedifferentiation in endometrial carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Endometrial Cancer: Transforming Care through Science; 2023 Nov 16-18; Boston, Massachusetts. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(5_Suppl):Abstract nr PR006.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".