Regression of cervical intraepithelial neoplasia by zerumbone in female Balb/c mice prenatally exposed to diethylstilboestrol: involvement of mitochondria-regulated apoptosis.
BACKGROUND
Cervical cancer is the second most common cause of cancer death in women. We have demonstrated previously that zerumbone (ZER) has an anti-cancer effect towards human cervical cancer cells (HeLa).


METHODS
Anti-cancer properties of ZER were investigated using female Balb/c mice exposed prenatally to diethylstilboestrol. Female offspring have been treated with ZER (4, 8 and 16 mg/kg), normal saline and cisplatin (10mg/kg; positive control). The anti-cancer properties of ZER were evaluated using histopathology, TdT-mediated dUTP nick end labeling (TUNEL) Assay and immunohistochemical staining of Bcl-2-associated X protein (Bax), a key protein in mitochondrial pathway of apoptosis. In addition, laser capture microdissection microscopy isolated RNA was amplified using reverse transcriptase polymerase chain reaction (RT-PCR) based on the specific primer of B-cell lymphoma 2 (Bcl-2).


RESULTS
Treatment with ZER resulted (P<0.05, chi(2) statistics) in the regression of cervical intraepithelial neoplasia (CIN) resembling cisplatin effect (10mg/kg). TUNEL micrographs showed the absence of apoptosis in cancerous tissues treated with normal saline compared to ZER and cisplatin where abundant apoptotic cells were noticed. A post hoc analysis showed a significant (P<0.01) difference in mean percentage of apoptosis between normal saline treatment (0%), ZER (15.7%) and cisplatin (21.7%). Immunohistochemical staining of Bax protein revealed that ZER modulates the expression of this apoptosis marker. Administration of ZER has also modulated the expression of Bcl-2 gene.


CONCLUSIONS
These findings showed that ZER induces apoptosis efficiently in cervical tissues from female Balb/c mice treated prenatally with diethylstilboestrol. This suggested that ZER, a plant-derived compound, could be introduced as a new chemo-preventive agent for CIN in future.
Abdelwahab
Siddig Ibrahim
SI
MAKNA-UPM Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia. siddigroa@yahoo.com
Abdul
Ahmad Bustamam
AB
Devi
Nirmala
N
Taha
Manal Mohamed Ehassan
MM
Al-zubairi
Adel Sharaf
AS
Mohan
Syam
S
Mariod
Abdelbasit Adam
AA
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D002273:Carcinogens / Q000633:toxicity; D004054:Diethylstilbestrol / Q000633:toxicity; D005260:Female; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012717:Sesquiterpenes / Q000627:therapeutic use*; D002583:Uterine Cervical Neoplasms / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D002578:Uterine Cervical Dysplasia / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*
D000970:Antineoplastic Agents; D002273:Carcinogens; D012717:Sesquiterpenes; C403304:zerumbone; D004054:Diethylstilbestrol