FIGURE 5.

Luteolin suppresses apoB secretion from HepG2 cells and differentiated Caco2 cells. HepG2 cells (A–C) or Caco2 cells (E and F) were cultured with the indicated concentration of luteolin for 12 h (A, E, and F) or 3 h (B and C), and total RNA, whole cell extracts, and media were isolated. A, B, and F, the samples were subjected to SDS-PAGE and immunoblotting (IB) with anti-apoB or anti-β-actin antibodies. The same results were obtained in three separate experiments. C and E, real-time PCR analysis was performed, and relative mRNA levels were obtained after normalization of 36B4 mRNA. The mRNA levels without luteolin addition are represented as 1. All data are expressed as means ± S.E. (error bars) (n = 3). *, p < 0.05. D, HepG2 cells were transfected with either control (siCon) or HNF4α siRNA oligonucleotides (siHNF4α), cultured with medium A for 48 h, and re-fed the medium containing luteolin (50 μm) for 9 h before harvest. The whole cell extracts and media were isolated and subjected to SDS-PAGE and immunoblotting with anti-apoB, anti-HNF4α, or anti-β-actin antibodies. The same results were obtained in three separate experiments.