Synergistic inhibition of glioma cell proliferation by Withaferin A and tumor treating fields.
Glioblastoma (GBM) is the most aggressive and lethal form of brain cancer. Standard therapies are non-specific and often of limited effectiveness; thus, efforts are underway to uncover novel, unorthodox therapies against GBM. In previous studies, we investigated Withaferin A, a steroidal lactone from Ayurvedic medicine that inhibits proliferation in cancers including GBM. Another novel approach, tumor treating fields (TTFields), is thought to disrupt mitotic spindle formation and stymie proliferation of actively dividing cells. We hypothesized that combining TTFields with Withaferin A would synergistically inhibit proliferation in glioblastoma. Human glioblastoma cells (GBM2, GBM39, U87-MG) and human breast adenocarcinoma cells (MDA-MB-231) were isolated from primary tumors. The glioma cell lines were genetically engineered to express firefly luciferase. Proliferative potential was assessed either by bioluminescence imaging or cell counting via hemocytometer. TTFields (4 V/cm) significantly inhibited growth of the four cancer cell lines tested (n = 3 experiments per time point, four measurements per sample, p < 0.02 at least; 2-way ANOVA, control vs. treatment). The combination of Withaferin A (10-100 nM) with TTFields significantly inhibited the growth of the glioma cells to a degree beyond that of Withaferin A or TTFields alone. The interaction of the Withaferin A and TTFields on glioma cells was found to be synergistic in nature (p < 0.01, n = 3 experiments). These findings were validated by both bioluminescence and hemocytometric measurements. The combination of Withaferin A with TTFields represents a novel approach to treat GBM in a manner that is likely better than either treatment alone and that is synergistic.
['Chang|Edwin|E|http://orcid.org/0000-0002-5672-0520', 'Pohling|Christoph|C|', 'Beygui|Nooshin|N|', 'Patel|Chirag B|CB|', 'Rosenberg|Jarrett|J|', 'Ha|Dong Ho|DH|', 'Gambhir|Sanjiv S|SS|']
D000230:Adenocarcinoma D000970:Antineoplastic Agents D001932:Brain Neoplasms D001943:Breast Neoplasms D045744:Cell Line, Tumor D049109:Cell Proliferation D003131:Combined Modality Therapy D004317:Doxorubicin D004599:Electric Stimulation Therapy D005910:Glioma D006801:Humans D049409:Luciferases, Firefly D013696:Temperature D054358:Withanolides
Withaferin A Tumor treating fields Glioblastoma Alternating electric fields Combination therapy Synergy