Abstract B081: EWS::FLI1 alters DNA damage induced protein dynamics at the RNAPII CTD
Bibliographic record
Abstract
Abstract Ewing sarcoma (EwS) is an aggressive pediatric bone cancer with limited treatment options, highlighting a drastic need for novel therapeutics. EwS is driven by translocation of the EWSR1 low complexity domain and most often the DNA binding domain of FLI1, making up the oncogenic fusion protein EWS::FLI1. Accumulating evidence suggests that EWS::FLI1 alters the biophysical properties of EWS and EWS::FLI1 phase separated condensates. We have previously shown that EWS::FLI1 prevents the release of the double strand break (DSB) repair protein BRCA1 from RNA Polymerase II (RNAPII) complexes, inhibiting BRCA1 mediated DSB repair. However, how EWS::FLI1 alters protein dynamics at the RNAPII complexes is not understood. In this work we show that EWS::FLI1 co-localization to RNAPII C-Terminal Domain (CTD) protein hubs causes enhanced phase separation, imitating a hardening of RNAPII CTD condensates. Additionally, we find that treatment with DNA damaging agents decreases BRCA1 occupancy at RNAPII CTD protein hubs. Expression of EWS::FLI1 in this in cellulo system suggests inhibition of BRCA1 release from RNAPII phase separated entities upon DNA damage. Overall, this data indicates that EWS::FLI1 mediated changes in phase state alters heterotypic protein-protein interactions at the RNAPII complexes. Furthermore, we find that RNAPII CTD phase separated entities are refractory to THZ1 drug treatment. This underscores the physiological significance condensate biology plays in drug efficacy and drug resistance. In conclusion, our results prompt further investigation into EWS::FLI1 affects on protein-protein interactions at RNAPII condensates. Our findings are novel as we look at heterotypic phase condensate biology in cellulo, whereas most phase studies are conducted in vitro and focus on homotypic interactions. Moreover, though much work was conducted on BRCA1 and RNAPII interaction and damage-induced release in the 1990s and early 2000s, little is understood about the relationship of BRCA1 and RNAPII and certainly not in the context of EWS::FLI1. Importantly, this work provides a basis for the physiological role of condensate biology in EWS::FLI1 mediated BRCA1 and RNAPII protein-protein dynamics. Citation Format: Aiola Stoja, Xiaoping Xu, David S Libich, Alexander J. R. Bishop. EWS::FLI1 alters DNA damage induced protein dynamics at the RNAPII CTD [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pediatric Cancer Research; 2024 Sep 5-8; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl):Abstract nr B081.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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) | 0.004 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".