Liquid crystal-related compound-induced cell growth suppression and apoptosis in the chronic myelogenous leukemia...

Liquid crystals are the state of matter existing between the liquid and the crystalline phase, and there is a recent surging interest in its biological effects. Our previous study showed that liquid crystal-related compounds (LCRCs), which are precursors of the liquid crystal, enhanced hematopoietic differentiation at a relatively low concentration (Biol Pharm Bull, 32, 2009). However, biological potentials of LCRCs on tumor cells are unclear. In this study, the biological activity of 16 LCRCs to a chronic myelogenous leukemia cell line, K562, was evaluated. As a result, two compounds, 2-(4-butoxyphenyl)-5-(4-hydroxyphenyl)pyrimidine (compound 7) and 2-{4-(4-hexyloxyphenyl)phenyl}-5-hydroxypyrimidine (compound 9) showed marked growth suppression of K562 cells at μM range. These compounds are similar in structure with a core of three aromatic rings including a pyrimidine ring and residues of one alkyl chain and one hydroxide on either side. In addition, only compound 7 induced the activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, and apoptosis of K562 cells. The contrasting results between compounds 7 and 9 indicate different mechanisms to suppress the cell proliferation between the two compounds. These results suggest the possibility of LCRCs for application as new antitumor drugs.