Abstract C031: Ras processing by RRSP protease as a strategy to inhibit Ras-driven tumors
Notice bibliographique
Résumé
Abstract RAS genes are the most frequently mutated oncogenes in human cancers encoding four highly-related proteins that are critical molecular hubs for cancer cell proliferation and survival. Although promising results have been recently reported in early trials for KRas G12C inhibitors, there are no FDA-approved drugs that are effective against Ras-driven cancers, and Ras is still considered one of the most elusive targets in cancer research. We discovered the Ras-Rap1-Specific Protease (RRSP) from bacterium Vibrio vulnificus. RRSP is a naturally occurring endopeptidase that site-specifically cleaves the major Ras isoforms (H, N and K) and the most common mutated Ras oncoproteins (G12V, G13D and Q61R) within the Switch I region. In order to bring RRSP into cancer cells, RRSP was fused to diphtheria toxin binding subunit B (DTB). DTB delivers RRSP into the cytosol of targeted cells via binding to its receptor hHB-EGF (human heparin-binding epidermal growth factor-like growth factor). KRAS mutations occur in up to 50% of colorectal cancer (CRC) and in approximately 2% of triple-negative breast cancer (TNBC). However, 50% of TNBC show Ras upregulation via mutation-independent activation mechanisms. We investigated the anticancer potential of RRSP in CRC HCT-116 KRAS G13D as well as TNBC MDA-MB-231 KRAS G13D and MDA-MB-436 KRAS WT cell lines. RRSP was successfully delivered via DTB into CRC and TNBC cancer cell lines as indicated by Ras cleavage and pERK1/2 dephosphorylation at concentrations as low as 10 pM. As a consequence of Ras processing, a strong decrease in cell viability and proliferation was observed in all cell lines tested as per crystal violet staining and CellTiter Glo assay. A catalytically-dead mutant of RRSP carrying an amino acid substitution in its active site (RRSP*-DTB) did not show Ras processing nor reduced cell viability. Interestingly, our in vivo xenograft data demonstrated that, unlike RRSP*-DTB, RRSP-DTB effectively inhibited TNBC MDA-MB-436 and MDA-MB-231 tumor growth with no obvious toxicity. Proof of RRSP-target engagement was confirmed by loss of pERK1/2 phosphorylation via immunohistochemical analysis of tumor sections. We also found that RRSP-DTB strongly reduced the size and viability of 3-dimensional CRC HCT-116 spheroids in a time and dose-dependent manner. Moreover, an independent experiment at Charles River showed significant inhibition of tumor growth in a CRC HCT-116 xenograft model. Altogether our results revealed that, by physically processing Ras, RRSP strongly inhibits tumor growth in subcutaneously implanted human CRC and TNBC Ras-dependent tumors bearing either mutant or wild-type KRAS. This work supports further development of RRSP as an anticancer therapeutic for a broad spectrum of Ras-driven tumors and has the potential to take anti-Ras therapy to the next level. Citation Format: Vania Vidimar, Greg L Beilhartz, Roman A Melnyk, Karla JF Satchell. Ras processing by RRSP protease as a strategy to inhibit Ras-driven tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C031. doi:10.1158/1535-7163.TARG-19-C031
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».