January 23, 2012. In an article published today in the journal BMC Gastroenterology, Korean researchers report a benefit for the flavonoid luteolin, which occurs in some fruits and vegetables, in reducing the growth of cultured colon cancer cells.
In earlier research, Professor Jung Han Yoon Park of Hallym University in Chuncheon and colleagues found that luteolin decreases the growth of colon cancer cells by stimulating programmed cell death (apoptosis) and cell cycle arrest. In the current study, the team cultured the cells with luteolin and/or insulin-like growth factor-1 (IGF-1), which stimulates cancer growth.
A reduction in the secretion of insulin-like growth factor II (IGF-II) occurred in colon cancer cells treated with luteolin, and a decline in levels of IGF receptor precursor protein was observed within two hours. IGF-II occurs in higher levels in colon cancer cells compared to normal colon cells, and is believed to induce uncontrolled cell division and growth in cancer. When administered with IGF-1, luteolin also inhibited IGF-1’s growth stimulatory effect, by affecting the cell signaling pathways that IGF-1 activates in cancer.
“Luteolin reduced IGF-I-dependent activation of the cell signaling pathways PI3K, Akt, and ERK1/2 and CDC25c,” stated Jung Han Yoon Park, who is also affiliated with Kangwon National University. “Blocking these pathways stops cancer cells from dividing and leads to cell death. Our study, showing that luteolin interferes with cell signaling in colon cancer cells, is a step forward in understanding how this flavonoid works. A fuller understanding of the in vivo results is essential to determine how it might be developed into an effective chemopreventive agent.”