Molecular mechanism behind the synergistic activity of diphenylmethyl selenocyanate and Cisplatin against murine tumor model.

Various preclinical, clinical and epidemiological studies have already well established the cancer chemopreventive and chemoprotective potential of selenium compounds. In addition to its protective efficacy, recent studies have also proved the abilities of selenium compounds to induce cell death specifically in malignant cells. Therefore, our intention is to improve the therapeutic efficacy of an alkylating agent, cisplatin, by the adjuvant use of an organoselenium compound, diphenylmethyl selenocyanate (DMSE). It was observed that combined treatment decreased the tumor burden significantly through reactive oxygen species generation and modulation of antioxidant and detoxifying enzyme system in tumor cells. These activities ultimately led to significant DNA damage and apoptosis in tumor cells. Study of the molecular pathway disclosed that the adjuvant treatment caused induction of p53, Bax and suppressed Bcl-2 followed by the activation of caspase cascade. Furthermore, a concomitant decrease in cisplatin-induced nephrotoxicity and hematopoietic toxicity by DMSE might also have enhanced the efficacy of cisplatin and provided survival advantage to the host. Results suggested that the combination treatment with DMSE and cisplatin may offer potential therapeutic benefit, and utilization of cisplatin in cancer chemotherapy exempt of its limitations.

Intervention in cyclophosphamide induced oxidative stress and DNA damage by a flavonyl-thiazolidinedione based organoselenocyanate and evaluation of its efficacy during adjuvant therapy in tumor bearing mice.

A novel flavonyl-thiazolidinedione based organoselenocyanate compound was synthesized and established as nontoxic at the doses of 2.5 and 5 mg/kg b.w. in mice. Oral administration of the compound in combination with cyclophosphamide (CP) resulted in an improved therapeutic efficacy which was mostly evidenced in terms of tumor burden and protection of normal cells. The adjuvant therapy was proved to be immensely significant in increasing the mean survivability of the tumor bearing hosts. Reduction in the tumor volume was manifested through the induction of apoptosis and generation of ROS in transformed cells. Moreover, the organoselenium compound could efficiently suppress CP-induced DNA damage, chromosomal aberration, hepatic damage and enhanced the activities of various antioxidant enzymes in normal cells.

Naphthalimide based novel organoselenocyanates: finding less toxic forms of selenium that would retain protective efficacy.

A series of naphthalimide based organoselenocyanates were synthesized and screened for their toxicity as well as their ability to modulate several detoxifying/antioxidative enzyme levels at a primary screening dose of 3 mg/kg b.w. in normal Swiss albino mice for 30 days. Compound 4d showed highest activity in elevating the detoxifying/antioxidant enzymes levels.