Toxicity of areca nut ingredients: activation of CHK1/CHK2, induction of cell cycle arrest, and regulation of MMP-9 and TIMPs production in SAS epithelial cells.
BACKGROUND
There are 600 million betel quid chewers around the world. betel quid chewing is a major risk factor of oral cancer. Why betel quid components induce oral cancer is not clear.


METHODS
Cytotoxicity of areca nut extract and arecoline (an areca nut alkaloid) to SAS oral epithelial cell line was evaluated by trypan blue dye exclusion and MTT assays. Cell cycle distribution and apoptosis was analyzed by propidium iodide staining flow cytometry. Chk1 and chk2 activation was analyzed by Pathscan phospho-enzyme-linked immunosorbent assay. Metalloproteinase-9 (MMP-9), tissue inhibitors of metalloproteinase (TIMPs) production was measured by enzyme-linked immunosorbent assay.


RESULTS
Areca nut extract (800 μg/mL) and arecoline (>0.4 mmol/L) caused cell death, apoptosis, and cell cycle arrest of SAS cells. Areca nut extract and arecoline stimulated Chk1 and Chk2 phosphorylation in SAS cells. Areca nut extract stimulated cellular MMP-9 but suppressed TIMP-1 and TIMP-2 production.


CONCLUSIONS
Areca nut components activate Chk1/Chk2, alter cell cycle regulation/apoptosis, MMP-9, and TIMPs production, contributing to the pathogenesis of oral carcinogenesis.
Biomedical Science Team, Chang Gung University of Science and Technology, Kwei-Shan, Taoyuan, Taiwan.
Mei-Chi
MC
Chang
Chiu-Po
CP
Chan
Wei-Ting
WT
Wang
Bei-En
BE
Chang
Jang-Jaer
JJ
Lee
Shuei-Kuen
SK
Tseng
Sin-Yuet
SY
Yeung
Liang-Jiunn
LJ
Hahn
Jiiang-Huei
JH
Jeng
D001114:Areca / Q000737:chemistry*; D001115:Arecoline / Q000633:toxicity; D002453:Cell Cycle / Q000187:drug effects*; D002478:Cells, Cultured; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2 / Q000378:metabolism*; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology; D005434:Flow Cytometry; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009754:Nuts / Q000737:chemistry; D010936:Plant Extracts / Q000633:toxicity*; D011494:Protein Kinases / Q000378:metabolism*; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism*; D014062:Tongue Neoplasms / Q000188:drug therapy / Q000201:enzymology
D010936:Plant Extracts; D019714:Tissue Inhibitor of Metalloproteinases; D001115:Arecoline; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C000605867:CHEK1 protein, human; C578634:CHEK2 protein, human; D000071877:Checkpoint Kinase 1; D020780:Matrix Metalloproteinase 9