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The authors declare that they have no competing interests.
JI and MH were responsible for performing the majority of assays, discussing the study design and manuscript writing. YT and YF were responsible for performing a portion of the studies. AY was responsible for conceptualization of study ideas, study design, synthesization of liquid crystal compounds. IK was responsible for the entire project including conceptualization of study ideas, study design, evaluating results, study discussion, data analysis, manuscript writing and funding the study. All authors read and approved the final manuscript.
The aim of this study was to evaluate the biological and pharmaceutical activities of 14 amphiphilic liquid-crystalline compounds (LCs), i.e, phenylpyrimidine derivatives possessing D-glucamine and cyanobiphenyl derivatives with a terminal hydroxyl unit.
The cytotoxic properties of the LCs on the cell growth, cell cycle distribution, and cell signaling pathway of U937 human leukemic monocyte lymphoma cells were assessed by flow cytometry and western blot analysis. Some LCs showed cytostatic effects, suppressing cell growth via S-phase arrest and without apoptosis in U937 cells. To investigate the mechanisms of the LC-induced S-phase arrest, proteins relevant to cell cycle regulation were investigated by western blot analysis. The rate of LC-induced S-phase arrest was congruent with the decreased expression of MCM2, cyclin A, cyclin B, CDK2, phospho-CDK1 and Cdc25C. Observed changes in cell cycle distribution by LC treated might be caused by insufficient preparation for G2/M transition. Considering the structure of the LCs, the rod-like molecules displaying cytotoxicity against U937 cells possessed flexible spacers with no bulky polar group attached via the flexible spacer.
Our results revealed that some LCs showed cytotoxic properties against non-solid type tumor human leukemic cells via LC-induced S-phase arrest and decreasing expression of several cell cycle related proteins.