PMA synergistically enhances apicularen A-induced cytotoxicity by disrupting microtubule networks in HeLa cells.
BMC Cancer
; 14: 36, 2014 Jan 22.
Article
en En
| MEDLINE
| ID: mdl-24447339
ABSTRACT
BACKGROUND:
Combination therapy is key to improving cancer treatment efficacy. Phorbol 12-myristate 13-acetate (PMA), a well-known PKC activator, increases the cytotoxicity of several anticancer drugs. Apicularen A induces cytotoxicity in tumor cells through disrupting microtubule networks by tubulin down-regulation. In this study, we examined whether PMA increases apicularen A-induced cytotoxicity in HeLa cells.METHODS:
Cell viability was examined by thiazolyl blue tetrazolium (MTT) assays. To investigate apoptotic potential of apicularen A, DNA fragmentation assays were performed followed by extracting genomic DNA, and caspase-3 activity assays were performed by fluorescence assays using fluorogenic substrate. The cell cycle distribution induced by combination with PMA and apicularen A was examined by flow cytometry after staining with propidium iodide (PI). The expression levels of target proteins were measured by Western blotting analysis using specific antibodies, and α-tubulin mRNA levels were assessed by reverse transcription polymerase chain reaction (RT-PCR). To examine the effect of combination of PMA and apicularen A on the microtubule architecture, α-tubulin protein and nuclei were visualized by immunofluorescence staining using an anti-α-tubulin antibody and PI, respectively.RESULTS:
We found that apicularen A induced caspase-dependent apoptosis in HeLa cells. PMA synergistically increased cytotoxicity and apoptotic sub-G1 population induced by apicularen A. These effects were completely blocked by the PKC inhibitors Ro31-8220 and Go6983, while caspase inhibition by Z-VAD-fmk did not prevent cytotoxicity. RNA interference using siRNA against PKCα, but not PKCß and PKCγ, inhibited cytotoxicity induced by combination PMA and apicularen A. PMA increased the apicularen A-induced disruption of microtubule networks by further decreasing α- and ß-tubulin protein levels in a PKC-dependent manner.CONCLUSIONS:
These results suggest that the synergy between PMA and apicularen A is involved by PKCα activation and microtubule disruption, and that may inform the development of novel approaches to treat cancer.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Protocolos de Quimioterapia Combinada Antineoplásica
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Neoplasias del Cuello Uterino
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Microtúbulos
Límite:
Female
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Humans
Idioma:
En
Revista:
BMC Cancer
Asunto de la revista:
NEOPLASIAS
Año:
2014
Tipo del documento:
Article