Enhanced Cytotoxic Effects of Arenite in Combination with Active Bufadienolide Compounds against Human Glioblastoma Cell Line U-87

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 19; p. 6577
• Main Authors: Yuan, Bo, Li, Jingmei, Miyashita, Shin-Ich, Kikuchi, Hidetomo, Xuan, Meiyan, Matsuzaki, Hirokazu, Iwata, Naohiro, Kamiuchi, Shinya, Sunaga, Katsuyoshi, Sakamoto, Takeshi, Hibino, Yasuhide, Okazaki, Mari
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2022; MDPI
• Subjects: Analysis; Apoptosis; arenobufagin; Arsenic; Arsenite; Autophagy; Blood-brain barrier; Brain cancer; Care and treatment; Caspase-8; Caspase-9; Cell cycle; Cell death; Confidence intervals; Cytotoxicity; Development and progression; DNA damage; Drug dosages; Drug therapy, Combination; gamabufotalin; Gene expression; Glioblastoma; Glioblastoma cells; Glioblastoma multiforme; Inactivation; Jagged1 protein; Metabolites; Patient outcomes; Japan
• DOI: 10.3390/molecules27196577
• ISSN: 1420-3049

The cytotoxicity of a trivalent arsenic derivative (arsenite, AsIII) combined with arenobufagin or gamabufotalin was evaluated in human U-87 glioblastoma cells. Synergistic cytotoxicity with upregulated intracellular arsenic levels was observed, when treated with AsIII combined with arenobufagin instead of gamabufotalin. Apoptosis and the activation of caspase-9/-8/-3 were induced by AsIII and further strengthened by arenobufagin. The magnitude of increase in the activities of caspase-9/-3 was much greater than that of caspase-8, suggesting that the intrinsic pathway played a much more important role in the apoptosis. An increase in the number of necrotic cells, enhanced LDH leakage, and intensified G2/M phase arrest were observed. A remarkable increase in the expression level of γH2AX, a DNA damage marker, was induced by AsIII+arenobufagin. Concomitantly, the activation of autophagy was observed, suggesting that autophagic cell death associated with DNA damage was partially attributed to the cytotoxicity of AsIII+arenobufagin. Suppression of Notch signaling was confirmed in the combined regimen-treated cells, suggesting that inactivation of Jagged1/Notch signaling would probably contribute to the synergistic cytotoxic effect of AsIII+arenobufagin. Given that both AsIII and arenobufagin are capable of penetrating into the blood–brain barrier, our findings may provide fundamental insight into the clinical application of the combined regimen for glioblastoma.