cytochrome-c-t and beauvericin

One known cyclic peptide, beauvericin, was isolated from the secondary metabolites of mangrove endophytic fungi Fusarium sp. (No. DZ27) in South China Sea. Its structure was determined by spectral analyses and comparisons with reference data from literatures. Beauvericin inhibited growth of KB and KBv200 cells potently with IC50 values of 5.76 ± 0.55 and 5.34 ± 0.09 μM, respectively. Furthermore, beauvericin induced apoptosis through mitochondrial pathway, including decrease of relative oxygen species generation, loss of mitochondrial membrane potential, release of cytochrome c, activation of Caspase-9 and -3, and cleavage of PARP. Additionally, regulation of Bcl-2 or Bax was not involved in the apoptosis induced by beauvericin in KB and KBv200 cells.

Topics: Antineoplastic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 9; Cell Line, Tumor; Cytochromes c; Depsipeptides; Fungi; Fusarium; Humans; KB Cells; Membrane Potential, Mitochondrial; Mitochondria; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2

Beauvericin (BEA), a cyclic hexadepsipeptide from Codyceps cicadae, possesses anti-convulsion, anti-arrhythmia, sedation, and anti-tumor activities. It has been reported that BEA induces apoptosis in several cancer cell lines. However, the molecular mechanism underlying the BEA-induced apoptotic process is not yet clearly understood. In the present study, the intracellular signaling pathways of BEA-induced apoptosis in human non-small cell lung cancer (NSCLC) A549 cells were investigated using morphological analysis and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) technique. In this study, BEA-induced apoptosis in human NSCLC A549 cells demonstrated a BEA concentration- and treatment time-dependent manner. This BEA-induced apoptosis in human NSCLC A549 cells was also accompanied by the up-regulation of Bax, Bak, and p-Bad and down-regulation of p-Bcl-2, but no effect on the levels of Bcl-X(L) or Bad proteins. Moreover, the BEA treatment resulted in a significant reduction of mitochondrial membrane potential, increase in the release of mitochondrial cytochrome c (cyt c), and activation of caspase 3. Furthermore, treatment with caspase 3 inhibitor (z-DEVD-fmk) was capable to prevent the BEA-induced caspase 3 activity and cell death. These results clearly demonstrate that the induction of apoptosis by BEA involves multiple cellular/molecular pathways and strongly suggest that pro- and anti-apoptotic Bcl-2 family proteins, mitochondrial membrane potential, mitochondrial cyt c, and caspase 3, they all participate in BEA-induced apoptotic process in human NSCLC A549 cells.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Caspase 3; Caspases; Cell Line, Tumor; Cell Survival; Cytochromes c; Depsipeptides; DNA Fragmentation; Humans; In Situ Nick-End Labeling; Lung Neoplasms; Membrane Potentials; Mitochondria; Proto-Oncogene Proteins c-bcl-2

Beauvericin (BEA), a cyclic hexadepsipeptide, induces cell death in human leukemia cells (CCRF-CEM) and the process of BEA-induced cell death has been speculated to undergo an apoptotic pathway. In the present study, several well-characterized factors, known to play important roles in apoptotic pathway, were investigated in BEA-induced CCRF-CEM cell death. CCRF-CEM cells were treated with BEA at concentrations from 1 to 10 microM for up to 24 h. The incidence of nuclear fragmentation and apoptotic body formation in the cells, cytosolic caspase-3 activity, mitochondrial membrane potential, and release of cytochrome c (Cyt c) from mitochondria in BEA-treated cells were determined and compared with that in untreated cells. Moreover, to investigate the role of intracellular Ca++ in this cell death process, CCRF-CEM cells were primed with 3 microM of BAPTA/AM, a Ca++ chelator, to exclude intracellular Ca++ prior to the BEA treatment. The data revealed that BEA-induced cell death in CCRF-CEM cells exhibited a dose- and time-dependent manner. The incidence of nuclear fragmentation and apoptotic body formation was significantly increased in CCRF-CEM cells treated with BEA at concentrations of 1 microM or greater. Increase of cytosolic caspase-3 activity was also observed in BEA-treated cells with a dose-dependent manner. In addition, increased release of Cyt c from mitochondria was also observed in the cells treated with 10 microM BEA in a time-dependent pattern. The BAPTA/AM pretreatment partially blocked BEA-induced cell death in CCRF-CEM cells, indicating that intracellular Ca++ plays an important role, maybe as a mediator in cell death signaling, in this cell death pathway. The results support the notion that BEA-induced cell death in CCRF-CEM cells likely undergo through an apoptotic pathway on the basis of increase of release of Cyt c from mitochondria, increase of caspase-3 activity, and some observed typical apoptotic cellular changes in morphology.

Topics: Apoptosis; Calcium; Caspase 3; Caspases; Cell Death; Cell Line, Tumor; Chelating Agents; Cytochromes c; Cytosol; Depsipeptides; Dose-Response Relationship, Drug; Egtazic Acid; Humans; Morpholines; Precursor Cell Lymphoblastic Leukemia-Lymphoma