Role of the Cyclin-Dependent Kinase Inhibitor p27<sup>Kip1</sup>in Androgen-Induced Inhibition of CAMA-1 Breast Cancer Cell Proliferation
Bibliographic record
Abstract
Androgens are known to inhibit the growth of breast cancer cells, but the molecular mechanism of androgen-induced growth inhibition remains unknown. To address this question, we examined functional and quantitative alterations in cell cycle regulators in the E-responsive CAMA-1 breast cancer cell line. We report here that the androgen 5 alpha-dihydrotestosterone inhibits the proliferation of CAMA-1 breast cancer cells. This inhibition of cell proliferation was dose dependent, and maximal inhibition of E2-stimulated proliferation was observed at the concentration of 1 nM 5 alpha-dihydrotestosterone. 5 alpha-Dihydrotestosterone-induced growth arrest was accompanied by an increase in the proportion of cells in the G(1) phase of the cell cycle. Compared with control cells, 5 alpha-dihydrotestosterone-treated cells showed an increase in the relative proportion of hypophosphorylated retinoblastoma protein consistent with G(1) arrest. In CAMA-1 cells, 5 alpha-dihydrotestosterone caused an accumulation of the cyclin-dependent kinase inhibitor p27(Kip1). Cyclin E-cyclin-dependent kinase-2-associated kinase activity was strongly inhibited in 5 alpha-dihydrotestosterone-treated cells, and immunoprecipitation-Western blot analysis showed an increase in the amount of p27(Kip1) associated with cyclin E-cyclin-dependent kinase-2 complexes. These results suggest that inhibition of breast cancer cell growth by androgens may be mediated at least in part by inactivation of the cyclin E-cyclin-dependent kinase-2 complexes by p27(Kip1).
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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) | 0.001 | 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".