Kaempferol induces apoptosis in glioblastoma cells through oxidative stress.
Despite recent advances in understanding molecular mechanisms involved in glioblastoma progression, the prognosis of the most malignant brain tumor continues to be dismal. Because the flavonoid kaempferol is known to suppress growth of a number of human malignancies, we investigated the effect of kaempferol on human glioblastoma cells. Kaempferol induced apoptosis in glioma cells by elevating intracellular oxidative stress. Heightened oxidative stress was characterized by an increased generation of reactive oxygen species (ROS) accompanied by a decrease in oxidant-scavenging agents such as superoxide dismutase (SOD-1) and thioredoxin (TRX-1). Knockdown of SOD-1 and TRX-1 expression by small interfering RNA (siRNA) increased ROS generation and sensitivity of glioma cells to kaempferol-induced apoptosis. Signs of apoptosis included decreased expression of Bcl-2 and altered mitochondrial membrane potential with elevated active caspase-3 and cleaved poly(ADP-ribose) polymerase expression. Plasma membrane potential and membrane fluidity were altered in kaempferol-treated cells. Kaempferol suppressed the expression of proinflammatory cytokine interleukin-6 and chemokines interleukin-8, monocyte chemoattractant protein-1, and regulated on activation, normal T-cell expressed and secreted. Kaempferol inhibited glioma cell migration in a ROS-dependent manner. Importantly, kaempferol potentiated the toxic effect of chemotherapeutic agent doxorubicin by amplifying ROS toxicity and decreasing the efflux of doxorubicin. Because the toxic effect of both kaempferol and doxorubicin was amplified when used in combination, this study raises the possibility of combinatorial therapy whose basis constitutes enhancing redox perturbation as a strategy to kill glioma cells.
Sharma
Vivek
V
National Brain Research Centre, near NSG Campus, Manesar, Gurgaon, Haryana-122050, India.
Joseph
Christy
C
Ghosh
Soumya
S
Agarwal
Anindita
A
Mishra
Manoj Kumar
MK
Sen
Ellora
E
D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D018932:Chemokine CCL2 / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D005909:Glioblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D044949:Kaempferols / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D013879:Thioredoxins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
C111835:CCL2 protein, human; D018932:Chemokine CCL2; D015850:Interleukin-6; D016209:Interleukin-8; D044949:Kaempferols; D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C000606290:SOD1 protein, human; D013879:Thioredoxins; C006552:kaempferol; D004317:Doxorubicin; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases