Exatecan Mesylate is a DNA topoisomerase I inhibitor, with an IC₅₀ of 2.2 μM (0.975 μg/mL), and can be used in cancer research. IC50 & Target: IC50: 2.2 μM (topoisomerase I)^[1] In Vitro: Exatecan Mesylate is a potent topoisomerase I inhibitor, with an IC₅₀ of 0.975 μg/mL. Exatecan Mesylate (DX-8951f) significantly inhibits the proliferation of several cancer cell lines, with mean GI₅₀s of 2.02 ng/mL, 2.92 ng/mL, 1.53 ng/mL, and 0.877 ng/mL for breast cancer cells, colon cancer cells, stomach cancer cells and lung cancer cells, respectively^[1]. Exatecan Mesylate (DX-8951f) displays cytotoxic activities against PC-6, PC-6/SN2-5 cells, with mean GI₅₀s of 0.186 and 0.395 ng/mL, respctively. Exatecan Mesylate (34 nM) stabilizes DNA-TopoI complexes in PC-6 and PC-6/SN2-5 cells^[3]. In Vivo: Exatecan Mesylate (DX-8951f, 3.325-50 mg/kg, i.v.) exhibits antitumor activities in the mice model bearing tumor cells, without toxic death^[1]. Exatecan Mesylate (15, 25 mg/kg, i.v.) hightly inhibits MIA-PaCa, BxPC-3 primary tumor growth in the MIA-PaCa-2 early-stage model and early-stage model of BxPC-3. Exatecan Mesylate (15, 25 mg/kg, i.v.) also significantly suppresses BxPC-3 lymphatic metastasis and completely eliminates lung metastasis in the BxPC-3 late-stage cancer model^[2].