Abstract 1991: PDCD4 de-repression of Bcl-xl IRES-mediated translation leads to enhanced chemo-resistance of glioblastoma multiforme tumors.
Bibliographic record
Abstract
Abstract Glioblastoma multiforme (GBM) is the most prevalent form of tumor of the central nervous system with an average survival time of less than one year. Given the location and characteristics of GBM only limited treatment options are available, thus understanding the mechanisms of GBM formation or progression may lead to the development of novel treatment options. Strikingly, a common feature of GBM is the loss of expression of the tumor suppressor programmed cell death 4 (PDCD4) which correlates with adverse outcomes for patients in response to chemo- or radiation therapy. Through both transcriptional and translational regulation, PDCD4 has been shown to regulate many proteins within the cell, although the precise mechanism of target selection is not known. We have hypothesised that silencing of PDCD4 in glioblastomas leads to an altered expression of apoptosis-regulating proteins resulting in the suppression of apoptotic signals and enhanced chemo-resistance. Indeed, we show that low levels of PDCD4 correlate with an increase in the anti-apoptotic Bcl-xL protein. Importantly, Bcl-xL is regulated at the level of protein synthesis through the internal ribosome entry site (IRES) in its 5’ untranslated region (UTR). We further show that PDCD4 regulates the activity of the Bcl-xL IRES, and is therefore an IRES specific translational regulator. Importantly, reintroduction of PDCD4 into glioblastoma cells or directly inhibiting Bcl-xL with the chemical inhibitor ABT-737 sensitizes these cells to doxorubicin, thus enhancing cell death. In summary, our work provides a novel role for PDCD4 as a translational regulator of Bcl-xL as well as a potential therapeutic option for the treatment of GBM. Citation Format: Urszula Liwak, Lindsay E. Jordan, Federico Roncaroli, Martin Holcik. PDCD4 de-repression of Bcl-xl IRES-mediated translation leads to enhanced chemo-resistance of glioblastoma multiforme tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1991. doi:10.1158/1538-7445.AM2013-1991
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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) | 0.002 | 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".