The Effects of Selenium-Enriched Yeast on the Proliferation and Apoptosis of Human Breast Cancer Cells MCF-7

• Main Author: 謝芳琴
• Other Authors: 陳伯中
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/92856181408460720455

碩士 === 弘光科技大學 === 營養醫學研究所 === 99 === Abstract Breast cancer with estrogen receptor (ER) were treated by hormone therapy, like tamoxifen (Tam). Tam competed for ER with estrogen (E2) could induce apoptosis of breast cancer and drug-resistance under a long-term take was found recently. Studies reported that selenium (Se) compounds, methylseleninic acid (MSA) or methylselenocysteine (MSC) may cause apoptosis induction for cancer cells and prevent production of chemical drug-resistance. Selenium-enriched yeast (YSe) have multiple Se forms and provides Se as a supplement. The effects of ER-positive breast cancer by selenium-enriched yeast (YSe) or combination with Tam in vitro still remains unclear. Therefore, the present investigation aimed to compare the anti-proliferation and apoptosis of ER-positive breast cancer cell line MCF-7 treatment with YSe, MSC and MSA, respectively. Cell viability, apoptosis, apoptotic body formation were observed in the condition of E2 or Tam+E2. Our results showed that YSe (100, 750, 1500ng Se/ ml) caused a time- and dose-dependent increased in early-stage and late-stage apoptosis on MCF-7 cells. 100ng Se/ ml of YSe markedly increased early-stage apoptosis compared to 1500ng Se/ ml of MSA and MSC. However, more late-stage apoptosis of cells were observed by MSA than by YSe and MSC at the same concentration of 1500ng Se/ ml. On the other hand, YSe (100ng Se/ ml) had higher cell proportion of early-stage apoptosis than MSA and MSC (1500ng Se/ ml) did in the Tam+E2 condition. Comparison of MSA and MSC (1500ng Se/ ml), obvious increase of late-stage apoptosis was found in combination of Tam+E2 with YSe (1500ng Se/ ml). therefore, no matter in which conditions of E2 or Tam+E2 is, treatment with YSe (100, 750, 1500ng Se/ ml) could cause MCF-7 cells apoptosis in early stage better than with MSA or MSC. It suggested that YSe may make MCF-7 cells apoptosis in the early stage first, then enter in the late stage or necrosis. By contrast, induction of late-stage apoptosis or necrosis for MCF-7 cells may cause by MSA or MSC directly. In conclusion, the effects of anti-proliferation and apoptosis on MCF-7 cells treated by YSe were found. Furthermore, the activity of Tam on inhibition growth of MCF-7 cells were enhanced in combination with YSe. Thus, Se-enriched yeast has much greater potential as a adjuvants for anti-hormone therapy to ER-positive breast cancer. Key word: MCF-7 cells, selenium-enriched yeast, estrogen, tamoxifen, proliferation, apoptosis, necrosis