Abstract 4381: The novel direct-acting vascular targeting agent NGR-TNF exerts <i>in vivo</i> antitumor activity by inducing endothelial and tumor cell death in the absence of proangiogenic bone-marrow derived cell recruitment
Bibliographic record
Abstract
Abstract Treatment with either certain chemotherapy drugs at maximum tolerated dose (e.g. paclitaxel, cyclophosphamide, 5-FU), vascular-disrupting agents (VDAs; e.g. fosbretabulin, Oxi4503), or local irradiation can rapidly induce mobilization and subsequent tumor homing of proangiogenic bone marrow derived cells (BMDCs), such as circulating endothelial progenitor cells (CEPs), CD11b/Tie-2-expressing monocytes (TEMs), CD11b+Gr1+ neutrophils and myeloid-derived suppressor cells (MDSCs). Increase in several growth factors and chemokines, such as SDF-1, G-CSF as well as osteopontin, contribute to the mobilization of these BMDCs that can colonize the drug treated tumors preferentially at the viable tumor rim that characteristically remains after treatment with drugs such as VDAs. This process promotes angiogenesis and rapid tumor regrowth, thus diminishing the overall antitumor activities of the aforementioned treatments. NGR-TNF, presently in advanced clinical development, is a direct-acting vascular targeting agent coupling the CNGRCG peptide (NGR), homing to angiogenic blood vessels, and tumor necrosis factor alpha (TNF). Experiments performed in the Lewis lung carcinoma (LLC) model, suggested that when administrated at low doses, NGR-TNF causes a decrease of tumor blood vessels density and induces apoptosis of tumor cells without inducing cytokine-rebound and recruitment of pro-angiogenic BMDC. In order to extend these results, we investigated whether NGR-TNF fails to mobilize proangiogenic BMDC even after repeated treatments and in a highly aggressive and metastatic tumor model. LLC and 4T1 mammary gland carcinoma cells were subcutaneously implanted respectively into immunocompetent C57BL/6J or Balb/C mice. Blood was obtained by cardiac puncture or retro-orbital sinus bleeding, 4, 24 hours or 1 week after single or repeated treatments with either NGR-TNF at low and high dose or saline. Using flow cytometry CEPs were defined as CD45−/CD13+/flk-1+/CD117+/7AAD−, TEMs as CD45+/CD11b+/Tie2+ and MDSCs as CD45+/CD11b+/Gr1+ cells. At low doses, NGR-TNF exerts a control of 4T1 primary tumor growth, without inducing cytokine rebound and pro-angiogenic BMDCs mobilization. In addition, even after repeated administrations at low doses, NGR-TNF fails to mobilize or recruit to the tumor site different subtypes of BMDCs. Therefore, low doses of NGR-TNF exert an antitumor activity without inducing a reactive pro-angiogenic host response, and as such provide an explanation and the rationale for the successful use of lower dose NGR-TNF administration protocols in the clinic. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4381. doi:1538-7445.AM2012-4381
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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) | 0.005 | 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".