[Experimental study on the influence of Gynostemma pentaphyllam Mak upon point mutation of Ha-ras oncogene in blocking leukoplakia from canceration].
OBJECTIVE
To study the influence of Gynostemma pentaphyllam Mak (GP) upon point mutation of Ha-ras oncogene the molecular mechanism of GP in blocking canceration, and the relationship between Ha-ras oncogene and canceration of leukoplakia.


METHODS
DMBA induced carcinogeneses of the buccal pouch mucosa of the hamsters were divided into leukoplakia model group(LKG) and GP treated group(GPG). Point mutation (codon 61) of Ha-ras oncogene was detected by PCR-SSCP in both groups.


RESULTS
The mutation incidence of LKG was 22.96%, while the mean incidence of GPG was 7.59% (The incidences of C20-OH group, glucoside group and aglucon group were 5.32%, 6.25% and 11.00% respectively). When treated with DMBA for 4 to 8 weeks, the mutation incidence of LKG ranged from 11.10% to 40.00%, while GPG ranged from 0 to 10.70%.


CONCLUSIONS
GP has outstanding cancer blocking effect chiefly affected by free C20-OH. Mutation of Ha-ras oncogene plays an important role in leukoplakia canceration.
Zhou
Z
Z
Department of Oral Medicine, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
Tang
G
G
Zhong
W
W
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000008:administration & dosage; D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D011905:Genes, ras / Q000235:genetics*; D029774:Gynostemma; D007972:Leukoplakia, Oral / Q000235:genetics / Q000517:prevention & control*; D009061:Mouth Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy; D028321:Plant Preparations / Q000494:pharmacology* / Q000627:therapeutic use; D017354:Point Mutation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational
D002273:Carcinogens; D028321:Plant Preparations; D015127:9,10-Dimethyl-1,2-benzanthracene; D004247:DNA