The oncogenic transcription factor c-Maf has been proposed as an ideal therapeutic target for multiple myeloma (MM), a not-yet-curable malignancy of plasma cells. In the present study, we establish a c-Maf-based luciferase screen system and apply it to screen a homemade library composed of natural products from which bruceine B (BB) is identified to display potent antimyeloma activity. BB is a key ingredient isolated from the Chinese traditional medicinal plant Brucea javanica (L.) Merr. (Simaroubaceae). BB inhibits MM cell proliferation and induces MM cell apoptosis in a caspase-3-dependent manner. The mechanism studies showed that BB inhibits c-Maf transcriptional activity and downregulates the expression of CCND2 and ITGB7, the downstream genes typically modulated by c-Maf. Moreover, BB induces c-Maf degradation via proteasomes by inducing c-Maf for K48-linked polyubiquitination in association with downregulated Otub1 and USP5, two proven deubiquitinases of c-Maf. We also found that c-Maf activates STAT3 and BB suppresses the STAT3 signaling. In the in vivo study, BB displays potent antimyeloma activity and almost suppresses the growth of myeloma xenografts in 7 days but shows no overt toxicity to mice. In conclusion, this study identifies BB as a novel inhibitor of c-Maf by promoting its degradation via the ubiquitin-proteasomal pathway. Given the safety and the successful clinical application of bruceine products in traditional medicine, BB is ensured for further investigation for the treatment of patients with MM.
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Annexin V-FITC/PI Apoptosis Kit(细胞凋亡试剂盒-适用贴壁细胞 除C6流式细胞仪以外的流式细胞仪)
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Annexin V-FITC/PI Apoptosis Kit(贴壁细胞专用)(C6流式细胞仪专用)
- ¥860.00 – ¥1,510.00
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- AP101
- 凋亡试剂盒
Annexin V-FITC/PI Apoptosis Kit(适用于除C6以外的流式细胞仪)
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Annexin V-FITC/PI Apoptosis Kit (C6专用)
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