Diallyl trisulphide-induced apoptosis in human melanoma cells involves downregulation of Bcl-2 and Bcl-xL expression and activation of caspases.
BACKGROUND
Although diallyl trisulphide (DATS) has been found to induce apoptosis in various tumour cells, its cytotoxicity in melanoma cells has not yet been defined and the molecular pathway by which DATS induces apoptosis is not well understood.


OBJECTIVE
To determine growth inhibition of DATS in human melanoma cells (A375 and M14) by inducing apoptosis, and to investigate the mechanism underlying such effects.


METHODS
Growth inhibition by DATS was estimated by the tetrazolium assay. Apoptosis induction in DATS-treated cells was assessed by staining with 4',6-diamidino-2-phenylindole (DAPI) and double staining with annexin V and propidium iodide. Expression of Bcl-2, Bax, Bcl-xL/Bcl-xS, cytochrome c release, activation of caspase-9 and poly(ADP-ribose) polymerase (PARP) were determined by western blotting. The activity of caspase-3 was measured using a colorimetric assay.


RESULTS
DATS exerted its cytotoxic effect in a time-dependent and dose-dependent manner by inducing apoptosis in A375 and M14 cells. Expression of Bcl-2 and Bcl-xL was downregulated. Release of cytochrome c and activation of the downstream effectors caspase-3, caspase-9 and PARP were detected after DATS sensitization.


CONCLUSIONS
DATS inhibits growth of melanoma cells by inducing apoptosis in association with downregulation of Bcl-2 and Bcl-xL and activation of caspases.
Zhou
C
C
Department of Dermatology, Second Affiliated Hospital, Sun Yat-Sen University, Guangdong, China.
Mao
X-P
XP
Guo
Q
Q
Zeng
F-Q
FQ
D000498:Allyl Compounds / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation; D004789:Enzyme Activation; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008545:Melanoma / Q000235:genetics / Q000473:pathology*; D012878:Skin Neoplasms / Q000235:genetics / Q000473:pathology*; D013440:Sulfides / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*; D051020:bcl-X Protein / Q000378:metabolism
D000498:Allyl Compounds; C494826:BAX protein, human; D013440:Sulfides; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C042577:diallyl trisulfide; D045304:Cytochromes c; D020169:Caspases