This study was aimed to investigate the anticancer activities and the mechanism of the anticancer activities of a novel anticancer agent - 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylthiocarbonylamino)phenylthiocarbamoylsulfanyl]propionic acid (2-AAPA). 2-AAPA was found to inhibit various human cancer cell lines with a narrow range of IC50 values (28-75 μM). These cell lines include lung (NCI-H226), prostate (PC-3), breast (MCF-7), skin (A431), melanoma (UACC-62 and SK-MEL-2), and renal (UO-31) cancers, as well as human ovarian cancers (OVCAR-3 and NCI/ADR-RES) which are resistant toward doxorubicin. Flow cytometric studies revealed that 2-AAPA induced cell cycle arrest at G2/M phase and produced significant cell apoptosis in UACC-62 cells. Through immunofluorescence studies, 2-AAPA was found to depolymerize microtubules and cause cell morphological change. An HPLC (high performance liquid chromatography) assay demonstrated that proteins were glutathionylated in both OVCAR-3 and UACC-62 cells when treated with 2-AAPA. A Western blot analysis also showed that a band corresponding to the molecular weight of tubulins was significantly glutathionylated in cell lysate obtained from UACC-62 cells treated with 2-AAPA. Considering the rich thiol content of tubulin proteins and the nature of protein glutathionylation, it is likely that microtubule function might be affected through microtubule glutathionylation resulting in cell cycle arrest at G2/M phase. Immunoprecipitation is being employed to confirm that tubulins are glutathionylated in cells treated with 2-AAPA. Together, our findings could lead to an antimitotic agent with a novel mechanism which is different than those of current antimitotic drugs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4422.