Abstract 4093: Prostate apoptosis response-4 (Par-4): A novel substrate of caspase-3 during apoptosis
Bibliographic record
Abstract
Abstract Prostate apoptosis response-4 (Par-4) is a ubiquitously expressed pro-apoptotic tumor suppressor protein. Par-4 is known to selectively induce apoptosis in cancer cells either by activating apoptosis or by inhibiting cell survival. Here, we show, for the first time, that Par-4 is a novel substrate of caspase-3 during apoptosis. We found that Par-4 is cleaved during cisplatin-induced apoptosis in human normal and cancer cell lines. Caspase-3-deficient MCF-7 cells did not show Par-4 cleavage in response to cisplatin treatment. This Par-4 cleavage was concomitant with Parp cleavage and generated a C-terminal fragment of approx. 25kDa. The cleavage of Par-4 was completely inhibited by Z-VAD-fmk (an inhibitor of caspase like protease) suggesting that caspase-3 like activity is involved in the cleavage of Par-4. Consistently, recombinant caspase-3 efficiently cleaved Par-4 in vitro for all cell lines tested, suggesting the involvement of this protease in Par-4 processing in vivo. Overexpression of caspase-3 in PC-3 cells increased caspase-3 activity, which further resulted in the cleavage of Par-4 in these cells. However, overexpression of a catalytic mutant caspase-3 (C163A) failed to induce Par-4 cleavage. Further, restoration of caspase-3 in MCF-7 cells showed a decrease in Par-4 levels with the appearance of the cleaved fragment. The cleavage of Par-4 in caspase-3 expressing MCF-7 cells was efficiently blocked by a caspase-3 inhibitor. These results establish for the first time that Par-4 is a novel substrate of caspase-3 both in vitro and in vivo. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4093. doi:10.1158/1538-7445.AM2011-4093
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.003 |
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".