A245 THE ROLE OF P53 ON P2Y6R EXPRESSION IN COLORECTAL CANCER.
Bibliographic record
Abstract
The G protein-coupled P2Y6 receptor (P2Y6R) is activated by extracellular UDP. In the colonic epithelium, it participates in the maintenance of the hydric balance by regulating NaCl secretion. More recently, P2Y6R activity was reported to worsen inflammatory symptoms in a mouse model of inflammatory bowel diseases (IBD). Long-term IBD-suffering patients are at higher risk of developing colorectal cancer (CRC). In response to chronic exposure to inflammatory stressors, p53 is one of the first mutated oncogene, which leads to colitis-associated CRC. We focused on the potential role of p53 in the regulation of P2Y6R expression in CRC. The hypothesis is that the presence of a mutant form of p53 will differentially regulate P2Y6R expression as compared to the wild-type protein. The general aim of our work is to characterize the molecular mechanisms associated with p53-dependent regulation of P2Y6R in CRC. More specifically, we will 1) determine and characterize the P2RY6 promoter in cancerous intestinal epithelial cells (cIEC) and 2) study the role of wild-type or mutant p53 on P2Y6R expression. The P2RY6 gene encodes for 8 messenger RNA (mRNA) variants. Most of them are encoding for the P2Y6R isoform 1 which is well characterized. However, mRNA variant 9 codes for an uncharacterized form of the receptor: isoform 2. We used 5’RACE experiments to identify the different transcription start sites (TSS) corresponding to the several mRNA variants and determined the amount of each variant in cIECs. We then cloned four consensus regions (R1, R2, R3 and R4) of the P2RY6 promoter encompassing the four previously identified TSS upstream of the luciferase reporter gene in the pGL4.10 vector. The pGL4.10-P2RY6 promoter constructs were cotransfected with wild-type p53 and mutant forms and transcription activity measured by luciferase assays. Chromatin immunoprecipitation (ChIP) assays were used to confirm the luciferase results. We identified four TSS in the P2RY6 promoter region and showed that Caco-2 cells expressed predominantly mRNA variant 9. Using luciferase assays, we showed that wild-type p53 can activate the promoter R1 and R4 regions, whereas p53 R273H mutant (p53R273H) has no effect on the transcriptional activity of the R1 region but significantly stimulated the R4 promoter region. The ChIP experiments showed that p53R273H could occupy the R4 but not the R1 region; whereas wild-type p53 could bind both R1 and R4 regions. Finally, AlphaScreen Surefire assays suggest that UDP also activates P2Y6R isoform 2. We showed that wild-type p53 and p53R273H mutant differently regulate P2Y6R expression in cIEC. Hence, p53R273H mutant seems to favor the expression of P2Y6R isoform 2 for which the function is not yet identified but are likely linked to stimulation of cell proliferation and resistance to apoptosis. CIHR
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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 | 0.000 |
| 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".