Naturally occurring flavonoid in herbs and vegetables found to induce cancer cell death
Being a widely studied flavonoid, luteolin’s biological activities are well-discussed in several studies. Besides having anti-inflammatory and antioxidant activities, luteolin is perhaps best-known for its anti-cancer activities.
According to a study published in the European Journal of Cancer Prevention, luteolin is able to prevent the development of tumors largely by inactivating chemical signals and gene expression pathways essential for cancer cells.
To explore the influence of luteolin on esophageal cancer cells, researchers at the Southeast University in China recently conducted an in vitro study using Eca 109 cells. Their objective was to determine the mechanisms underlying luteolin’s anti-cancer effects.
The researchers reported their findings in an article published in the journal Food Science and Human Wellness.
Luteolin stops the growth of cancer by inducing cancer cell apoptosis
For their experiment, the researchers exposed Eca 109 cells to different concentrations of luteolin (0, 40, 80, 120, 160, 200, 240 microMolar) for 24, 48 and 72 hours, respectively, and evaluated its effect on cell proliferation.
They also treated Eca 10 cells with 0, 40, 160 and 240 microMolar luteolin for 24 hours and used flow cytometry to determine its effect on cell cycle progression and apoptosis.
The researchers then analyzed the mRNA and protein expressions of caspase-9 and -3 — two enzymes involved in apoptosis — using real-time PCR and Western blot, respectively.
They found that luteolin inhibited the proliferation of Eca 109 cells at all concentrations in a time-dependent manner. The relative inhibition rate showed an inverted U-shaped association with luteolin concentration.
Luteolin also arrested the cell cycle in the S phase and induced apoptosis of Eca 109 cells at 40, 160 and 240 microMolar.
Additionally, the researchers reported that as luteolin concentration increased, its effects changed from promotional to inhibitory — that is, the effect of luteolin on the mRNA and protein expression of caspase-9 and caspase-3 first manifested as promotion, then inhibition.
Based on these findings, the researchers concluded that luteolin kills esophageal carcinoma cells by inducing cell apoptosis via increased expression of caspase-3 and -9.