Assessment of the effect of trichostatin A on HeLa cells through FT-IR spectroscopy.

Trichostatin A (TSA) is one of histone deacetylase (HDAC) inhibitor drugs which can suppress the enzymatic activity of deacytylases and promote the acetylation of both histone and nonhistone proteins in cells. Investigation of the effect of TSA on cellular acetylation is critical for better understanding of the antitumor drug's mechanism interacting with cancer cells. As Fourier transform infrared spectroscopy (FT-IR) is a powerful analytical tool which can detect nondestructively and quantitatively biological samples without biotagging and biolabeling, here we employed FT-IR spectroscopy to probe the chemical and structural changes of proteins in the TSA treated cells, and with the aid of fluorescent microscopy, we could scrutinize the time-dependent and dose effects on the acetylation level promoted by TSA. Our results showed that TSA caused an elevated level of cellular acetylation and conformational/structural changes of proteins in the cells, and a higher dosage of TSA caused a higher percent of α-helix structure accompanied by an increment of acetylation level in both histones and cytoskeleton proteins. This work therefore not only validates the usefulness of FT-IR spectroscopy in the quantitative assessment of cellular acetylation but also may open an avenue to the in-depth investigation of the effect of HDAC inhibitor drugs such as TSA on cancer cells.