Studies on the Anticancer Effect of Apigenin in KB Cell Xenograft Nude Mouse Model

Apigenin은 과일과 야채에 들어있는 플라보노이드로 다양한 악성 세포에 항증식효과를 보여준다. 세포성장 저해효과를 확인하기 위하여 KB 구강암세포주를 96 well plate에 $6{\times}10^3$ cells/well로 분주하고 24시간 후에 apigenin을 24시간 동안 처치하여 MTT assay를 수행하였다. Apigenin은 배양 후 용량 의존적으로 세포사를 유도하였다. Apigenin 100 ${\mu}M$ 을 24시간 동안 처치하고 대조군과 세포성장을 비교하였을 때 유의적인 감소를 확인하였다. KB 구강암세포주에서의 apoptosis를 확인하기 위해 DAPI 염색을 수행하였다. Apigenin을 처치한 세포에서 핵의 응축이 존재함을 형광현미경으로 확인하였다. 우리는 누드마우스에 KB 구강암세포주를 이식하여 세포 성장 억제 효과를 알아보았다. Apigenin을 마우스에 25, 50 mg/kg을 0.2 ml의 PBS에 녹여 경구투여 하였다. 종양 사이즈는 대조군과 25, 50 mg/kg apigenin 투여군을 비교하였을 때 유의적으로 감소하였다. Apoptosis 분석을 위해 TUNEL염색을 수행하였다. 25 mg/kg apigenin 투여군과 대조군을 비교하였을 때 apoptosis의 유의적인 증가를 확인하였다. 육안적 소견을 위한 H&E 염색은 이상이 없었다. 본 연구는 apigenin이 구강암세포주 성장 억제를 apoptosis의 유도를 통하여 확인하였다. Apigenin (4', 5, 7-trihydroxyflavone), a common dietary flavonoid abundantly present in fruits and vegetables, has shown remarkable anti-proliferative effects against various malignant cell lines. To observe the anti-proliferative effects, oral cavity cancer cell lines, $6{\times}10^3$ cells/well (96 well plate) of KB oral cavity tumor cells were plated and 24 hr later treated with apigenin for one day, after which MTT assay was performed. Apigenin induced cell death in a dose-dependent manner after incubation. Cell viability was significantly decreased in the group treated with 100 ${\mu}M$ apigenin for 24 hr (p<0.05) compared to the control group. To assess apoptosis, the nuclei of KB cells were stained with DAPI. The presence of chromatin condensation in the apigenin treated cells was detected on a fluorescent microscope ( ${\times}200$ ). We investigated the in vivo growth inhibitory effects of apigenin on oral cavity cancer KB tumor xenograft subcutaneously implanted in male nude mice. Apigenin was administered to mice by gavage at doses of 25 and 50 mg/kg/day in 0.2ml of PBS. Tumor volume was significantly decreased in 25 and 50 mg/kg apigenin-administration groups compared to the control group. For apoptosis analysis, TUNEL staining was performed. A significant increase in TUNEL positive cells was found in the 25 mg/kg apigenin administration group compared to the non- apigenin administration group. Histopathological changes were not observed. These results indicate that apigenin inhibits oral cavity cancer cell growth through the induction of apoptosis.