Combination treatment of MCF-7 spheroids by Pseudomonas aeruginosa HI1 levan and cisplatin

Abstract Treatment of cancer with chemotherapy drugs is a challenge because of drug resistance and severe side effects. This study aimed to evaluate the cytotoxicity of levan as a natural biopolymer alone and in combination with cisplatin. Consequently, honey isolate NRCA, Pseudomonas aeruginosa, recorded promising levansucrase activity and levan yield. Crude levan (CL) was dialyzed to dialyze levan (DL). Crude levan showed cytotoxicity effect by 69.5%, 74% on MCF-7 at 500 and 1000 μg/ml, respectively while it has a safe effect on normal cells. Dialyzed levan increased cancer cell viability. Combination treatment of CL and cisplatin significantly reduced the IC50 of cisplatin (9.4 μM) to 5.8 μM and 3.8 μM when combined with Levan 500 μg/ml and 1000 μg/ml, respectively. Crude levan cytotoxicity is a dose-independent with IC50 447 μg/ml. Levan did not cause DNA fragmentation in treated cells. Accordingly, treatment design to treat spheroids with a combination of both CL and cisplatin at different time intervals was suggested. This design was found to increase the cytotoxicity against MCF-7 spheroids and reduce the cytotoxicity of cisplatin on spheroids of normal cell line. It can be concluded that combination treatment of cisplatin and levan might decrease the IC50 of cisplatin and overcome side effects problems.