Differential Protein Expression in EC304 Gastric Cancer Cells Induced by Alphastatin

Objective: To explore the differential protein expression profile in EC304 gastric cancer cells induced byalphastatin.
Methods: Cultured EC304 cells in the exponential phase of growth were randomly divided intoalphastatin and control groups. Total proteins were extracted and the two dimensional electrophoresis (2-DE)technique was applied to analyze differences in expression with ImageMaster 2D Platinum 5.0 software. Proteinswere identified using the MASCOT database and selected differently expressed proteins were characterised bywestern blotting and immunofluorescence.
Results: 1350±90 protein spots were detected by the ImageMastersoftware in the 2-DE gel images from the control and alphastatin groups. The match rate was about 72-80% for thespectrum profiles, with 29 significantly different protein spots being identified, 10 upregulated, 16 downregulated,two new and one lost. The MASCOT search scores were 64-666 and the peptide matching numbers were 3-27 withsequence coverage of 8-62%. Twenty-three proteins were checked by mass spectrometry, including decrease inNm23 and profilin-2 isoform b associated with the regulation of actin multimerisation induced by extracellularsignals.
Conclusion: The proteome in EC304 cells is dramatically altered by alphastatin, which appears to playan important role in modulating cellular activity and anti-angiogenesis by regulating protein expression andsignal transduction pathways through Nm23 and profilin-2 isoform b, providing new research directions foranti-angiogenic therapy of gastric cancer.