Design and Synthesis of Novel Tetrapeptide Analogues as New Cytotoxic Agents

New series of compounds based on a tetrapeptide scaffold containing methyl sulfonyl group at the para position of a phenyl ring were synthesized and their cytotoxic activities were examined against several human cancer cell lines including MCF-7 (breast cancer Cell Line), HepG2 (human liver cancer Cell Line), HT-29 (Human Colorectal Adenocarcinoma Cell Line) and A549 (adenocarcinomic human alveolar basal epithelial cells) using MTT assay. Based on the results, among the synthesized peptides, 5e, 5f, 1g, and 3g were the most potent cytotoxic compounds that were more toxic than the reference compound, Celecoxib, against the tested cell lines. These compounds could be candidate for finding cytotoxic agents with new peptide scaffolds which show COX-2 inhibitory activity as well.