Role of p21WAF1 in green tea polyphenol-induced growth arrest and apoptosis of oral carcinoma cells

Stephen Hsu, Kajuana Farrey, John Wataha, Jill Lewis, James Borke, Baldev Singh, Haiyan Qin, Carol Lapp, David Lapp, Tuan Nguyen, George Schuster

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The cyclin-dependent kinase inhibitor p21WAF1 participates in cell growth, differentiation and apoptosis. p21WAF1 can be induced by green tea polyphenol EGCG in several cancer cell types, but its role in the oral cancer cell response to EGCG is not known. We found that EGCG upregulates p21WAF1 in an oral carcinoma cell line, OSC2, by cDNA microarray. The current study determined the impact of siRNA-suppressed p21WAF1 and its response to EGCG on cell growth, DNA synthesis and apoptosis by RT-PCR, Western blot, BrdU incorporation, MTT and caspase 3 activity assays. Suppression of p21WAF1 by siRNA resulted in an accelerated cell growth and DNA synthesis, and increased cell viability. However, caspase 3 activity was not significantly inhibited. The evidence showed that p21WAF1 is involved in EGCG-induced growth arrest of OSC2 cells, which may facilitate caspase 3-mediated apoptosis. Thus, expression of functional p21WAF1 may promote phytochemical-mediated growth arrest and apoptosis in oral carcinoma cells.

Original languageEnglish (US)
Pages (from-to)63-67
Number of pages5
JournalAnticancer research
Issue number1 A
StatePublished - Jan 2005


  • Apoptosis
  • EGCG
  • Green tea
  • Oral cancer
  • Polyphenol
  • p21

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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