p22 Is a Novel Plasminogen Fragment with Antiangiogenic Activity
Bibliographic record
Abstract
Tumor or tumor-associated cells cleave circulating plasminogen into three or four kringle-containing antiangiogenic fragments, collectively referred to as angiostatin. Angiostatin blocks tumor growth and metastasis by preventing the growth of endothelial cells that are critical for tumor vascularization. Here, we show that cancer and normal cells convert plasminogen into a novel 22 kDa fragment (p22). Production of this plasminogen fragment in a cell-free system has allowed characterization of the structure and activity of the protein. p22 consists of amino acid residues 78-180 of plasminogen and therefore embodies the first plasminogen kringle (residues 84-162) as well as additional N- and C-terminal residues. Circular dichroism and intrinsic fluorescence spectrum analysis have defined structural differences between p22 and recombinant plasminogen kringle 1 (rK1), therefore suggesting a unique conformation for kringle 1 within p22. Proliferation of capillary endothelial cells but not cells of other lineages was selectively inhibited by p22 in vitro. In addition, p22 prevented vascular growth of chick chorioallantoic membranes (CAMs) in vivo. Furthermore, administration of p22 at low dose suppressed the growth of murine Lewis lung carcinoma (LLC) metastatic foci in vivo. This is the first identification of a single kringle-containing antiangiogenic plasminogen fragment produced under physiological conditions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".