Grape seed proanthocyanidins promote apoptosis in human epidermoid carcinoma A431 cells through alterations in Cdki-Cdk-cyclin cascade, and caspase-3 activation via loss of mitochondrial membrane potential

Exp Dermatol. 2007 May;16(5):405-15. doi: 10.1111/j.1600-0625.2007.00542.x.


Dietary grape seed proanthocyanidins (GSPs) prevent photocarcinogenesis in mice. Here, we report that in vitro treatment of human epidermoid carcinoma A431 cells with GSPs inhibited cellular proliferation (13-89%) and induced cell death (1-48%) in a dose (5-100 mug/ml)- and time (24, 48 and 72 h)-dependent manner. GSP-induced inhibition of cell proliferation was associated with an increase in G1-phase arrest at 24 h, which was mediated through the inhibition of cyclin-dependent kinases (Cdk) Cdk2, Cdk4, Cdk6 and cyclins D1, D2 and E and simultaneous increase in protein expression of cyclin-dependent kinase inhibitors (Cdki), Cip1/p21 and Kip1/p27, and enhanced binding of Cdki-Cdk. The treatment of A431 cells with GSPs (20-80 mug/ml) resulted in a dose-dependent increase in apoptotic cell death (26-58%), which was associated with an increased protein expression of proapoptotic Bax, decreased expression of antiapoptotic Bcl-2 and Bcl-xl, loss of mitochondrial membrane potential, and cleavage of caspase-9, caspase-3 and PARP. Pretreatment with the pan-caspase inhibitor (z-VAD-fmk) blocked the GSP-induced apoptosis in A431 cells suggesting that GSP-induced apoptosis is associated primarily with the caspase-3-dependent pathway. Together, our study suggests that GSPs possess chemotherapeutic potential against human epidermoid carcinoma cells in vitro, further in vivo mechanistic studies are required to verify the chemotherapeutic effect of GSPs in skin cancers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Apoptosis / drug effects*
  • Carcinoma, Squamous Cell / drug therapy*
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Caspase 3 / metabolism*
  • Caspase Inhibitors
  • Cell Line, Tumor
  • Cyclin-Dependent Kinase Inhibitor Proteins / metabolism
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p27
  • Cyclin-Dependent Kinases / metabolism
  • Cyclins / metabolism*
  • Cysteine Proteinase Inhibitors / pharmacology
  • Enzyme Activation / drug effects
  • G1 Phase / drug effects
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Membrane Potential, Mitochondrial / drug effects
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases / metabolism
  • Proanthocyanidins / isolation & purification
  • Proanthocyanidins / pharmacology*
  • Signal Transduction / drug effects
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / metabolism
  • Skin Neoplasms / pathology
  • Vitis / chemistry


  • Amino Acid Chloromethyl Ketones
  • CDKN1A protein, human
  • CDKN1B protein, human
  • Caspase Inhibitors
  • Cyclin-Dependent Kinase Inhibitor Proteins
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Cysteine Proteinase Inhibitors
  • Intracellular Signaling Peptides and Proteins
  • Proanthocyanidins
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • Cyclin-Dependent Kinase Inhibitor p27
  • PARP1 protein, human
  • Poly (ADP-Ribose) Polymerase-1
  • Poly(ADP-ribose) Polymerases
  • Cyclin-Dependent Kinases
  • CASP3 protein, human
  • Caspase 3