RT Journal Article SR Electronic T1 Phenothiazines and Selenocompounds: A Potential Novel Combination Therapy of Multidrug Resistant Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 4921 OP 4928 DO 10.21873/anticanres.14495 VO 40 IS 9 A1 MÁRIÓ GAJDÁCS A1 MÁRTA NOVÉ A1 ÁKOS CSONKA A1 BORISZ VARGA A1 CARMEN SANMARTÍN A1 ENRIQUE DOMÍNGUEZ-ÁLVAREZ A1 GABRIELLA SPENGLER YR 2020 UL http://ar.iiarjournals.org/content/40/9/4921.abstract AB Background/Aim: Phenothiazines constitute a versatile family of compounds in terms of biological activity, which have also gained a considerable attention in cancer research. Materials and Methods: Three phenothiazines (promethazine, chlorpromazine and thioridazine) have been tested in combination with 11 active selenocompounds against MDR (ABCB1-overexpressing) mouse T-lymphoma cells to investigate their activity as combination chemotherapy and as antitumor adjuvants in vitro with a checkerboard combination assay. Results: Seven selenocompounds showed toxicity on mouse embryonic fibroblasts, while three showed selectivity towards tumor cells. Two compounds showed synergism with all tested phenothiazines in low concentration ranges (1.46-11.25 μM). Thioridazine was the most potent among the three phenothiazines. Conclusion: Phenothiazines belonging to different generations showed different levels of adjuvant activities. All the tested phenothiazines are already approved medicines with known pharmacological and toxicity profiles, therefore, their use as adjuvants in cancer may be considered as a potential drug repurposing strategy.