Abstract 923: Human embryonic stem cells exhibit altruistic cell death that release death signals having potent anti-cancer activity
Notice bibliographique
Résumé
Abstract Background: We recently described the altruistic stem cell (ASC) phenotype in human embryonic stem cells (hESCs) as well as in mesenchymal stem cells (1, 2). The ASC phenotype was characterized by altered state of p53/MDM2 feedback system that permitted the cells to transiently acquire an unstable state of low p53 allowing the cells to survive in extreme microenvironment (1). Interestingly, we noted that ASCs spontaneously returned to its basal state of high p53 after a period of two weeks (1, 2). In this study, we speculate that this return of p53 levels to basal state could be a safety mechanism to prevent malignant transformation of ASCs. We also speculate that ASCs may release soluble factors like high mobility group protein B1 (HMGB-1) that could selectively target the cells exhibiting abnormal p53 e.g. cancer cells. Here, we further characterized ASC phenotype and its fate. Methods: hESC, BG01 cells were exposed to extreme hypoxia followed by reoxygenation and then ABCG2+/SSEA3+ cells were flow cytometry sorted. This specific subpopulation is enriched in ASCs and could be cultured in vitro for two weeks (1). The post- hypoxia treated ABCG2+/SSEA3+ cells were maintained in serum free media, and subjected to apoptosis, and senescence assays. The conditioned media (CM) of these cells and subjected to HMGB-1 measurement by ELISA. To measure bystander apoptosis, teratocarcinoma cells (Tera-2) were treated with the CM followed by measurement of apoptosis. Results: Here we confirmed that p53 and MDM2 in ABCG2+/SSEA3+ cells exhibited return of oscillation between days 19-24. This was associated increase in apoptosis, and senescence of these cells. Apoptosis/senescence was decreased when treated with either Pifithrin α, an inhibitor of p53, or by siRNA silencing of p53, suggesting p53-dependent apoptosis. Additionally, treatment with Nutlin-3, an inhibitor of MDM2 (1) led to a 10-fold increase in apoptosis indicating that high MDM2 was required to prevent the apoptosis of ASCs. Thus, ASCs underwent spontaneous apoptosis (altruistic cell death) due to the return of p53/MDMD2 oscillation. We suggest that this return of p53 and associated apoptosis could be a safety mechanism to prevent malignant transformation of ASCs. Next, we found that the CM of ABCG2+/SSEA3+ cells contained high levels of HMGB-1 compared to the parental BG01 cells. Importantly, CM treatment led to p53 dependent apoptosis of Tera-2 cells. Furthermore, CM treatment also inhibited the growth of Tera-2 xenografts in NOD/SCID mice. Conclusion: Our results indicate that ASCs undergoes altruistic cell death, and releases death signal mediated by HMGB1 that can target neighboring cells exhibiting abnormal p53 including cancer cells. We suggest that this unique property of ASCs could be exploited as a novel cancer therapeutic. 1. Das B et al, Stem Cells, 2012; 30(8):1685-95. 2. Pal B et al, Cancer Research, 2016; Volume 76, Issue 14 Supplement, pp. 251 Note: This abstract was not presented at the meeting. Citation Format: Bidisha Pal, Seema Bhuyan, Jaishree Garhyan, Herman Yeger, Bikul Das. Human embryonic stem cells exhibit altruistic cell death that release death signals having potent anti-cancer activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 923. doi:10.1158/1538-7445.AM2017-923
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 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».