Gossypol decreased cell viability and down-regulated the expression of a number of genes in human colon cancer cells

Abstract

Plant polyphenol gossypol has anticancer activities. This may increase cottonseed value by using gossypol as a health intervention agent. It is necessary to understand its molecular mechanisms before human consumption. The aim was to uncover the effects of gossypol on cell viability and gene expression in cancer cells. In this study, human colon cancer cells (COLO 225) were treated with gossypol. MTT assay showed significant inhibitory effect under high concentration and longtime treatment. We analyzed the expression of 55 genes at the mRNA level in the cells; many of them are regulated by gossypol or ZFP36/TTP in cancer cells. BCL2 mRNA was the most stable among the 55 mRNAs analyzed in human colon cancer cells. GAPDH and RPL32 mRNAs were not good qPCR references for the colon cancer cells. Gossypol decreased the mRNA levels of DGAT, GLUT, TTP, IL families and a number of previously reported genes. In particular, gossypol suppressed the expression of genes coding for CLAUDIN1, ELK1, FAS, GAPDH, IL2, IL8 and ZFAND5 mRNAs, but enhanced the expression of the gene coding for GLUT3 mRNA. The results showed that gossypol inhibited cell survival with decreased expression of a number of genes in the colon cancer cells.

Figure 1

Chemical structure of gossypol (molar mass: 518.56 g/mol) (Image was from public domain Gossypol—Wikipedia).

Figure 2

Effect of gossypol on human colon cancer cell viability. Human colon cancer cells (COLO 225) were treated with various concentrations of gossypol for 2, 4, 8 and 24 h. The cell media were added with MTT assay reagent, and incubated for 2 h before adding MTT solubilization solution, shaken at room temperature overnight. “0 µg/mL” treatment corresponding to 1% DMSO in the culture medium, the vehicle control for the experiment. The color density in the wells was recorded at A570. The data represent the mean and standard deviation of 12 independent samples. “*” and “**” near the data points represent significance between the treatment and the control at p < 0.05 and p < 0.01, respectively.

Figure 3

Gossypol regulated the expression of genes coded for qPCR reference mRNAs, genes reported to be regulated by gossypol, and genes coded for DGAT and GLUT mRNAs in human colon cancer cells. Human colon cancer cells (COLO 225) were treated with gossypol for 8 h. The data represent the mean and standard deviation of three independent samples. (A) genes coded for qPCR reference mRNAs, (B) genes reported to be regulated by gossypol, (C) genes coded for DGAT mRNAs, (D) genes coded for GLUT mRNAs.

Figure 4

Gossypol regulated the expression of genes coded for TTP family, IL family, TTP-mediated proinflammatory cytokine and other mRNAs in human colon cancer cells. Human colon cancer cells (COLO 225) were treated with gossypol for 8 h. The data represent the mean and standard deviation of three independent samples. (A) genes coded for TTP family mRNAs. (B) genes coded for IL family mRNAs. (C) genes coded for TTP-mediated proinflammatory cytokine mRNAs. (D) genes coded for other TTP-mediated mRNAs.