Eugenol induces apoptosis and inhibits invasion and angiogenesis in a rat model of gastric carcinogenesis induced by MNNG.
OBJECTIVE
Combining apoptosis induction with anti-invasive and anti-angiogenic treatment is gaining increasing attention as a promising strategy for cancer chemoprevention. In the present study, eugenol (4-allyl-2-methoxyphenol) was evaluated for its chemopreventive effects on N-methyl-N(')-nitro-N-nitrosoguanidine (MNNG)-induced gastric carcinogenesis in Wistar rats by analyzing markers of apoptosis, invasion and angiogenesis.


METHODS
The expressions of markers of apoptosis (Bcl-2, Bcl-xL, Bax, Apaf-1, cytochrome C, caspase-9, caspase-3 and poly(ADP-ribose)polymerase; PARP), invasion (matrix metalloproteinase-2; MMP-2, matrix metalloproteinase-9; MMP-9, reversion-inducing cysteine rich protein with Kazal motifs; RECK and tissue inhibitors of metalloproteinase-2; TIMP-2) and angiogenesis (vascular endothelial growth factor; VEGF and VEGF receptor1; VEGFR1) in stomach tissue of experimental and control animals were measured by gelatin zymogram, immunohistochemical, Western blot and RT-PCR analysis.


RESULTS
Rats administered MNNG developed gastric carcinomas that displayed apoptosis avoidance coupled to upregulation of pro-invasive and angiogenic factors. Administration of eugenol induced apoptosis via the mitochondrial pathway by modulating the Bcl-2 family proteins, Apaf-1, cytochrome C, and caspases and inhibiting invasion, and angiogenesis as evidenced by changes in the activities of MMPs and the expression of MMP-2 and -9, VEGF, VEGFR1, TIMP-2 and RECK.


CONCLUSIONS
Phytochemicals such as eugenol that are capable of manipulating the equilibrium between pro- and anti-apoptotic proteins as well as the delicate balance between stimulators and inhibitors of invasion and angiogenesis are attractive candidates for preventing tumour progression.
Manikandan
Palrasu
P
Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar-608 002, Tamil Nadu, India.
Murugan
Ramalingam Senthil
RS
Priyadarsini
Ramamurthi Vidya
RV
Vinothini
Govindarajah
G
Nagini
Siddavaram
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D003720:Densitometry; D004195:Disease Models, Animal; D005054:Eugenol / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D007150:Immunohistochemistry; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D008769:Methylnitronitrosoguanidine; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000098:blood supply* / Q000139:chemically induced* / Q000235:genetics / Q000473:pathology
D009363:Neoplasm Proteins; D008769:Methylnitronitrosoguanidine; D005054:Eugenol; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9