In Vitro Characterization of the Bacteria-derived Hypoxia-selective Cytotoxin BE-43547.
Anticancer Res
; 43(12): 5319-5329, 2023 Dec.
Article
en En
| MEDLINE
| ID: mdl-38030202
ABSTRACT
BACKGROUND/AIM:
Hypoxia-activated pro-drugs, such as TH-302, may kill hypoxic treatment-resistant tumor cells, but have failed in clinical trials. This may be related to variable levels of drug-activating reductases. Compounds such as bacteria-derived BE-43547, which target hypoxic cells independently of reductases, may be beneficial. This study characterized the in vitro potency and hypoxia selectivity of BE-43547 and TH-302. MATERIALS ANDMETHODS:
Tumor cells were exposed to different oxygenation levels in the presence/absence of drug, and survival was quantified using total cell number (BE-43547) or clonogenic survival (BE-43547 and TH-302) assays. Half-maximal inhibitory concentration (IC50) values and the hypoxia-cytotoxicity-ratio (HCR normoxic IC50/hypoxic IC50) were determined from dose-response curves. Finally, both drugs were tested in spheroids exposed to 20% or 0% O2 for 24 h followed by assessment of clonogenic survival.RESULTS:
BE-43547 was highly potent and displayed little inter-cell line variability. Strongly enhanced cytotoxicity was observed under oxygen-restricted conditions with HCR's of ~100 and ~20 after 24 h of treatment with 0 or 0.5% O2, respectively. Reducing treatment time somewhat reduced hypoxia selectivity. Hypoxia selectivity was observed regardless of whether the drug was added before or during the hypoxic challenge. TH-302 IC50 values varied 10-fold under oxic conditions, whereas those of the anoxic-to-normoxic HCR varied from 15 to 88. Both BE-43547 and TH-302 were unable to completely sterilize anoxic incubated spheroids.CONCLUSION:
BE-43547 is highly hypoxia-selective, and unlike TH-302, displayed minimal variability between cell lines, suggesting that BE-43547 targets a fundamental feature/target that is only present, or of survival importance, during hypoxia. Spheroid experiments suggested inadequate tissue penetrability, which may be overcome by designing novel drug analogs.Palabras clave
Texto completo:
1
Colección:
01-internacional
Asunto principal:
Oxidorreductasas
/
Hipoxia
Límite:
Humans
Idioma:
En
Revista:
Anticancer Res
Año:
2023
Tipo del documento:
Article