Changes in cell membrane morphology of colon cancer cells (HCT116) after treatment with azurin derived hexapeptide 4 by AFM and STEM.

A6-amino acid peptide fragment of the azurin molecule was observed to act on HCT116 cancerous cells
and cell death was brought by apoptosis in vitro. Integrity of the cell membrane is an indispensable prerequisite for
preserving the biological characteristics of a cell. In this study, changes in the morphology and ultrastructure of
HCT116 (human colon carcinoma) was studied by atomic force microscopy (AFM) and Scanning Transmissiom
Electron Microscope (STEM) before and after treatment with the azurin derived hexapeptide. In response to
hexapeptide addition, the microstructure of the cell membrane of HCT116 cell displayed changes. With increase in
reaction time, the degree of morphological changes on the surface of cell membrane increased. These changes included
increase in the fluctuation of the surface components of the cell membrane, and roughness of cell. Cell viability was
done by MTT assay. Analysis of the cell membrane root-mean-square (RMS) roughness showed that under the action
of hexa peptide, RMS values for the cell membranes of HCT 116 cell type increased with time thus positively
correlating to the reaction time. This work is of high significance for the visual diagnosis of early stage of apoptosis in
colon cancer cells in response to azurin derived hexapeptide, The use of AFM and STEM can be a rapid and sensitive
visual method for studying the interaction between cells and drug.