Suppressive effects of liquid crystal compounds on the growth of the A549 human lung cancer cell line.

The aim of this study was to evaluate the biological activity and pharmacological activity of several amphiphilic liquid-crystalline compounds (LCs), i.e. phenylpyrimidine derivatives possessing D-glucamine and cyanobiphenyl derivatives with a terminal hydroxyl unit, to explore novel anti-cancer functions of the LCs. The anti-cancer properties of the LCs were investigated in A549 human lung cancer cells by assessing cell growth, cell cycle distribution, and cell signaling pathways using a flow cytometer and a Western blot analysis. In addition, the effect of LCs on the growth of WI-38 normal fibroblasts was examined. Consequently, the phenylpyrimidine derivatives and cyanobiphenyl derivatives showed cytostatic effects, causing the suppression of cell growth through G1 phase arrest in A549 cells. Further analyses using phenylpyrimidine derivatives and precursors of a cyanobiphenyl compound demonstrated the structure-activity relationships. One of the phenylpyrimidine derivatives inhibited A549 growth without any toxicity to normal fibroblasts. As a result, a novel pharmacological function was hypothesized to be inherent in the structure of the LCs themselves, and the dependence of the tumor-specific activity on the hydrophobic group of phenylpyrimidine derivatives therefore remains an interesting issue. Our results suggest the possibility that the LCs themselves may act as a novel type of chemotherapeutic agent.