The antitumor activities of ethaselen （BBSKE） in combination with cisplatin （CDDP） in vitro have been investigated in human stomach cancer cell line BGC 823 and human lung cancer cell line PG-BE1. MTT method was used to assess the individual effects of ethaselen and cisplatin and their combined effects on cell proliferation of BGC 823 cells and PG-BE1 cells. Additionally, we used the classic median effect theory to calculate the combination index （CI） of ethaselen and cisplatin with different dose regimes in combination, and compared the effective dosages of cisplatin in individual treatment and combination treatment. When ethaselen and cisplatin were used in combination, a synergistic effect was observed. The most remarkable synergistic effect was observed when the dose ratio of cisplatin to ethaselen was 2：3 in BGC 823 cell line and 1：3 in PG-BE1 cell line. The dose of cisplatin could be decreased markedly in combination group to reach the same inhibitory effect, and this effect was gradually raised with the increase of the concentration of drugs.
Ethaselen, an organoselenium compound designed and synthesized in the School of Pharmaceutical Sciences, Peking University, has been entitled to independent intellectual property rights both at home and abroad. As one of the novel antitumor drugs, ethaselen has been extensively studied in Phase I clinical trial, and its biological target is thioredoxin reductase. In this review, we focus on the ethaselen＇s efficacy and pharmacological actions, including antitumor effects both in vitro and in vivo, and immunologic functions. These research findings not only provide the theoretical basis for the anticancer study of ethaselen, but also guide the clinical trial of ethaselen.
