Page 4 - V. Proteomics

[V. Proteomics-3]

Quantitative Analysis Method for Posttranslational

Modifications of p53 in Colon Cancer Cell

Eda Ates¹˙², Young Sook Yoo¹, Min Jung Kang¹˙²

¹Molecular Recognition Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5,

Seongbuk-gu, Seoul 136-791, Republic of Korea, ²Division of Bio-Medical Science and Technology (Biological
Chemistry), KIST School, Korea University of Science and Technology , Seoul 02792, Republic of Korea

The tumor suppressor p53 plays a critical role in the response to cellular stress including DNA damage, hypoxia,

oncogene activation and ribosomal stress. The p53 protein, which is transcriptionally modified by posttranslational

modifications (PTMs), regulates hundreds of genes that control cell cycle arrest, apoptosis and senescence. Our
study’s aim is to develop a quantitative detection method for PTMs of p53 in colon cancer cell using capillary
electrophoresis-laser-induced fluorescence (CE-LIF). We have analyzed fluorescein isothiocyanate (FITC) labelled

phosphorylated p53 peptides and colon cancer cell line HCT116 which was treated with different concentrations of
doxorubicin. We developed a quantitative CE-LIF method for analysis of phosphorylated peptides of trypsin/Asp-

N digested p53 in HCT116 cells compared with human colon epithelial cell line. Compared with normal colon
epithelial cell line, results showed that HCT116 cells had an increased PTM levels as the concentration of doxorubicin

increase. Consequently, we have developed a sensitive, reproducible, cost effective and quantitative method for
analysis of PTMs in p53.