Abstract 4104: Protease-activated receptor 2, a KLK14 target in colon cancer cells
Bibliographic record
Abstract
Abstract Serine proteinases signal through proteinase-activated receptors (PARs). Our studies have implicated PAR1 and PAR4 (thrombin receptors) and PAR2 (trypsin receptor) in human colon cancer growth. However, endogenous activators of PARs in colon tumors are still unknown. Recently, members of the kallikrein-related peptidase (KLK) family have been shown to activate PARs in many cell systems. Thus, our aim was to determine if KLK14, a KLK family member, is expressed in colonic tumors and to see if this KLK can activate PARs in human colon cancer cells. The presence of KLK14 in colon cancer cell lines was assessed by RT-PCR, ELISA and immunofluorescence, and its expression in human colonic tissue was assessed by immunohistochemistry. The effects of recombinant KLK14 in parallel with PAR1/2 agonists (SFLLRN-NH2, an activating peptide for both PAR1 and PAR2; TFLLR-NH2, a selective activating peptide for PAR1 and the selective PAR2 agonists, 2-furoyl-LIGRLO-NH2; SLIGRL-NH2) were assessed for calcium flux, receptor internalization and ERK1/2 phosphorylation in a human colon cancer-derived HT29 cell line that expresses PAR1 and PAR2. We found that: a) KLK14 mRNA (RT-PCR) was present in 16 out of 16 human colon cancer cell lines, b) KLK14 protein is present (ELISA) in HT29 conditioned media and other colon cancer cell lines; c) there was strong staining of KLK14 in the cytoplasmic compartment of HT29 cells and of human colonic tumors (immunofluorescence and immunohistochemistry; paraffin sections) d) KLK14 (0.1 µM) caused prompt increases in intracellular calcium ([Ca2+]i) in HT29 cells (Microspectrofluorimetry with Fura 2/fluo-3). The KLK14-induced Ca2+-flux was abrogated after an initial challenge of the cells with SFLLRN-NH2 (100 µM), which desensitizes PAR1 and PAR2 simultaneously. Desensitization with 2-furoyl-LIGRLO-NH2 (10 µM) a potent PAR2 agonist, attenuated most of the Ca2+ flux induced by KLK14, whereas responses to TFLLR-NH2, the PAR1 agonist, were minimally affected. Consistently, a first challenge with thrombin did not affect KLK14-induced Ca2+ flux. These results strongly suggest that KLK14 activates preferentially PAR2 in HT29 cells. e) KLK14 initiates a dramatic loss of cell surface PAR2 (microscopic analysis) due to its internalization and f) KLK14 induces a rapid (within 5-10 min) and significant ERK1/2 phosphorylation in HT29 cells. This KLK14-PAR signaling pathway may represent a novel therapeutic target for colon tumorigenesis. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4104.
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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) | 0.004 | 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".