Leptomycin B (CI 940; LMB) is a potent inhibitor of the nuclear export of proteins. Leptomycin B inactivates CRM1/exportin 1 by covalent modification at a cysteine residue. Leptomycin B is a potent antifungal antibiotic blocking the eukaryotic cell cycle.
体外研究
Leptomycin B (LMB) is very potent in vitro against various cancer cell lines (IC50 values in the 0.1 to 10 nM range). Leptomycin B (LMB) inhibits SiHa, HCT-116, and SKNSH cells with IC50s of 0.4, 0.3 and 0.4 nM for a 72 hour exposure, respectively.
Leptomycin B (LMB) (0.5 nM) displays a synergistic effect on Gefitinib (0–32 μM)-induced cytotoxicity in A549 and H460 cell line. The simultaneous treatments of Gefitinib (0–32 μM) and Leptomycin B (0.5 nM) show synergistic cytotoxic effect on A549 as compared to Gefitinib alone at both 24 and 48 hours.
Cell Viability Assay
Cell Line:
The non-small cell lung cancer (NSCLC) cell lines A549 and H460
Concentration:
0.5 nM
Incubation Time:
24 and 48 hours
Result:
The IC50 of Gefitinib at 48 hours was 32.0±2.5 μM while it was significantly reduced to 25.0±2.1 μM with the combination of 0.5 nM Leptomycin B. The significant synergistic cytotoxic effect from co-treatment of 0.5 nM Leptomycin B with Gefitinib was also confirmed in H460 cell line.
Cell Viability Assay
Cell Line:
A549
Concentration:
0.5 nM
Incubation Time:
48 hours
Result:
0.5 nM Leptomycin B plus Gefitinib or Gefitinib alone had a decreased p-EGFR(Tyr1068) expressions compared with controls.
p-Akt (Ser473) was inhibited in a dose-response manner by Gefitinib treatments, but it was enhanced by gefitinib+Leptomycin B co-treatments compared with gefitinib alone.
A549 treated by Gefitinib+Leptomycin B had a higher expression of p-Erk1/2(Thr202/Tyr204) than A549 treated by Gefitinib alone.
体内研究
Leptomycin B (LMB) is poorly tolerated in vivo. Maximum tolerated dose (MTD) is 2.5 mg/kg for LMB (single i.v.) in HCT-116 tumor–bearing mice.The limited in vivo efficacy of Leptomycin B is due to off-target effects because our nuclear export inhibitors (NEIs) retain the potent inhibition of CRM1, but are clearly better tolerated in vivo.
分子式
C33H48O6
分子量
540.73
CAS号
87081-35-4
中文名称
来普霉素B;细霉素B
运输条件
Room temperature in continental US; may vary elsewhere.