Abstract 1183: Targeting the DNA repair pathway with BOLD-100 in <i>BRAF</i> mutant colorectal cancer
Bibliographic record
Abstract
Abstract Background: BRAF mutations (BRAFMT) occur in ∼10-15% of metastatic colorectal cancer (mCRC) and have a poor clinical outcome, in particular those with microsatellite stable (MSS) disease. Anti-BRAF/EGFR combinations have shown some increases in response rate, but this is associated with minor increases in overall survival. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC. Using publicly available gene expression data from 155 CRC cell lines (GSE59857), we recently identified that unfolded protein response (UPR) and DNA repair are dominant pathways deregulated in the consensus molecular subgroup 1/BRAFMT subgroup. The aim of this study was to investigate the role of BOLD-100, an inhibitor of the UPR regulator GRP78, in regulating the survival of CRC cells. Methods: A panel of isogenic paired and non-isogenic V600E BRAFMT and BRAFWT cells were used. BOLD-100, a ruthenium-based small molecule inhibitor, was obtained from BOLD Therapeutics. Cell Titre Glo, Flow Cytometry, Western blotting, Caspase 8, 3/7 activity, RNAi assays were used. RNA seq and IPA bioinformatic analyses were performed on BOLD-100-treated BRAFMT/WT CRC cells. A compound library including small molecules approved by the FDA was used. Results: In vitro CellTitre-Glo® and Annexin V/PI sensitivity studies showed that the BRAFMT, MSS CRC cells were highly sensitive to BOLD-100 with IC50 values between 9.25-31μM. Treatment with BOLD-100 resulted in early decreases in GRP78 levels and increases in expression levels of the endoplasmic reticulum stress protein CHOP, and this was associated with caspase-8 dependent cell death in the BRAFMT CRC cells. Notably, silencing of CHOP did not abrogate BOLD-100-induced cell death in BRAFMT CRC cells, indicating that the UPR pathway played no role in the cell death following BOLD-100. RNA seq and IPA analysis showed that cell cycle regulation and DNA repair were the most significant deregulated pathways following BOLD-100 treatment. Further mechanistic studies revealed that BOLD-100 induced rapid and potent increases in pATRT1989, pChk1S345 and γH2AX expression levels in BRAFMT cells. Using a small molecule compound library, we found that the ATR inhibitors AZD6783 and M4344 resulted in strong synergy and apoptosis when combined with BOLD-100, in particular in BRAFMT CRC cells. Moreover, we found that the ROS scavenger NAC abrogated BOLD-100 induced CHOP, pATRT1989, pChk1S345 and γH2AX levels and rescued cell death following BOLD-100 treatment in BRAFMT CRC cells. Conclusions: Taken together, we have identified a role for BOLD-100 in regulating the survival of BRAFMT CRC cells. Our data support further studies with BOLD-100, in particular in combination with ATRi, for the treatment of BRAFMT CRC tumours. Citation Format: Robbie Carson, Shivaali Karelia, Deborah Lavin, Vijay Tiwari, Richard Kennedy, Kienan Savage, Adam Carie, Jim Pankovich, Mark Bazett, Sandra Van Schaeybroeck. Targeting the DNA repair pathway with BOLD-100 in BRAF mutant colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1183.
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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) | 0.003 | 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".