A liquid crystal-related compound induces cell cycle arrest at the G2/M phase and apoptosis in the A549 human non-small cell lung cancer cell line

Abstract

Liquid crystals are the state of matter existing between liquid and crystalline phases, and recently there has been increasing interest in their biological effects. Following our recently reported work, we investigated the cell suppressive effects of liquid crystal-related compounds (LCRCs), which are precursors of liquid crystals, in the human non-small lung cancer cell line A549. We found that 2-(4-butoxyphenyl)-5-(4-hydroxyphenyl)pyrimidine (LCRC-1) dramatically suppressed cell growth. Treatment with 12 µM LCRC-1 for 12 h induced cell cycle arrest at the G2/M phase. Furthermore, LCRC-1 increased the sub-G1 fraction and Annexin V-positive cells and activated caspase-3 in A549 cells, which showed that it can induce apoptosis in these cells. Furthermore, because the induction of apoptosis by LCRC-1 was partly inhibited by treatment with pan-caspase inhibitor, it appeared that LCRC-1 induced apoptosis by a caspase-dependent pathway. The ability of LCRC-1 to cause DNA damage was assessed, but LCRC-1 did not induce expression of γ-H2AX, which is a marker of DNA damage. Treatment with LCRC-1 did not inhibit the proliferation of WI-38 normal fibroblast cells, which makes the tumor-specific suppressive effect of LCRC-1 attractive for its application as a new antitumor drug.