Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B(Cuc B) is a natural triterpenoid with potent anticancer activ...Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B(Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear. In the present study, the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells. The cells were treated with or without Cuc B, and the cytotoxicity was determined by MTT assay. The effect of Cuc B on metastasis was evaluated with wound healing, transwell, and adhesion assays. Furthermore, the adhesion of cancer cells to endothelial cells was determined. The protein expression was determined by Western blotting. Cuc B(< 100 nmol·L~^(-1)) showed no obvious cytotoxicity to MDA-MB-231 cells, but significantly inhibited migration, invasion, and adhesion to Matrigel, fibronectin, type I collagen, and endothelial cells. Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase(FAK) and paxillin in dose-and time-dependent manners. Furthermore, Cuc B induced intracellular reactive oxygen species(ROS) generation, which could be reduced by N-acetyl-l-cysteine(NAC). In addition, NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion, expression of FAK, but showed no effect on paxillin expression. In summary, Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells, demonstrating novel mechanisms for the anticancer effects of Cuc B.展开更多
Conjunctival melanoma(CM) is a rare and fatal malignant eye tumor. In this study, we deciphered a novel anti-CM mechanism of a natural tetracyclic compound named as cucurbitacin B(CuB). We found that CuB remarkably in...Conjunctival melanoma(CM) is a rare and fatal malignant eye tumor. In this study, we deciphered a novel anti-CM mechanism of a natural tetracyclic compound named as cucurbitacin B(CuB). We found that CuB remarkably inhibited the proliferation of CM cells including CM-AS16,CRMM1, CRMM2 and CM2005.1, without toxicity to normal cells. CuB can also induce CM cells G2/M cell cycle arrest. RNA-seq screening identified KIF20A, a key downstream effector of FOXM1 pathway, was abolished by CuB treatment. Further target identification by activity-based protein profiling chemoproteomic approach revealed that GRP78 is a potential target of CuB. Several lines of evidence demonstrated that CuB interacted with GRP78 and bound with a Kdvalue of0.11 μmol/L. Furthermore, ATPase activity evaluation showed that CuB suppressed GRP78 both in human recombinant GRP78 protein and cellular lysates. Knockdown of the GRP78 gene significantly induced the downregulation of FOXM1 and related pathway proteins including KIF20A, underlying an interesting therapeutic perspective. Finally, CuB significantly inhibited tumor progression in NCG mice without causing obvious side effects in vivo. Taken together, our current work proved that GRP78-FOXM1-KIF20A as a promising pathway for CM therapy, and the traditional medicine CuB as a candidate drug to hinder this pathway.展开更多
The natural product cucurbitacin B has been widely studied because of its multiple biological activities,especially its potent antitumor effects.However,modifications of cucurbitacin B are mainly focused on the C2 and...The natural product cucurbitacin B has been widely studied because of its multiple biological activities,especially its potent antitumor effects.However,modifications of cucurbitacin B are mainly focused on the C2 and C16 site,studies on the C25 acetoxy group are still limited.We successfully developed a palladium-catalyzed allylic coupling of cucurbitacin B with boronic acids,providing a one-step approach to expand the chemical diversity of the C25 position.Our method was protecting-group-free,showing a good functional group tolerance and a wide substrate scope under mild reaction conditions.A library of 29 derivatives was prepared,compounds 2q and 2u showed higher cytotoxicity against A549 cells than cucurbitacin B,compounds 2n and 2o maintained potency,and the introduced hydroxyl and amino groups could be further derived.展开更多
基金supported by the Science and Technology Development Fund,Macao S.A.R(FDCT)(No.039/2014/A1)the Research Fund of University of Macao(Nos.CPG2014-00012-ICMS,MYRG2016-00043-ICMS-QRCM,and MYRG2015-00091-ICMS-QRCM)
文摘Metastasis is responsible for the majority of cancer-related deaths and prevention of metastasis remains a big challenge for cancer therapy. Cucurbitacin B(Cuc B) is a natural triterpenoid with potent anticancer activities while its effect on metastasis remains unclear. In the present study, the inhibitory effect and mechanisms of Cuc B on metastasis were investigated in MDA-MB-231 breast cancer cells. The cells were treated with or without Cuc B, and the cytotoxicity was determined by MTT assay. The effect of Cuc B on metastasis was evaluated with wound healing, transwell, and adhesion assays. Furthermore, the adhesion of cancer cells to endothelial cells was determined. The protein expression was determined by Western blotting. Cuc B(< 100 nmol·L~^(-1)) showed no obvious cytotoxicity to MDA-MB-231 cells, but significantly inhibited migration, invasion, and adhesion to Matrigel, fibronectin, type I collagen, and endothelial cells. Cuc B dramatically inhibited the phosphorylation of focal adhesion kinase(FAK) and paxillin in dose-and time-dependent manners. Furthermore, Cuc B induced intracellular reactive oxygen species(ROS) generation, which could be reduced by N-acetyl-l-cysteine(NAC). In addition, NAC pretreatment could reverse Cuc B-induced suppression of migration and adhesion, expression of FAK, but showed no effect on paxillin expression. In summary, Cuc B suppressed ROS-dependent metastasis through FAK pathway in breast cancer MDA-MB-231 cells, demonstrating novel mechanisms for the anticancer effects of Cuc B.
基金supported by the National Mega-project for Innovative Drugs of China(2019ZX09721001-004-003)the National Natural Science Foundation of China(82003603 and 81872747)+1 种基金the Innovative Research Team of High-level Local Universities in Shanghai,the National Special Fund for State Key Laboratory of Bioreactor Engineering(2060204,China)Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism(2021 Sci&Tech 03-28,China).
文摘Conjunctival melanoma(CM) is a rare and fatal malignant eye tumor. In this study, we deciphered a novel anti-CM mechanism of a natural tetracyclic compound named as cucurbitacin B(CuB). We found that CuB remarkably inhibited the proliferation of CM cells including CM-AS16,CRMM1, CRMM2 and CM2005.1, without toxicity to normal cells. CuB can also induce CM cells G2/M cell cycle arrest. RNA-seq screening identified KIF20A, a key downstream effector of FOXM1 pathway, was abolished by CuB treatment. Further target identification by activity-based protein profiling chemoproteomic approach revealed that GRP78 is a potential target of CuB. Several lines of evidence demonstrated that CuB interacted with GRP78 and bound with a Kdvalue of0.11 μmol/L. Furthermore, ATPase activity evaluation showed that CuB suppressed GRP78 both in human recombinant GRP78 protein and cellular lysates. Knockdown of the GRP78 gene significantly induced the downregulation of FOXM1 and related pathway proteins including KIF20A, underlying an interesting therapeutic perspective. Finally, CuB significantly inhibited tumor progression in NCG mice without causing obvious side effects in vivo. Taken together, our current work proved that GRP78-FOXM1-KIF20A as a promising pathway for CM therapy, and the traditional medicine CuB as a candidate drug to hinder this pathway.
文摘The natural product cucurbitacin B has been widely studied because of its multiple biological activities,especially its potent antitumor effects.However,modifications of cucurbitacin B are mainly focused on the C2 and C16 site,studies on the C25 acetoxy group are still limited.We successfully developed a palladium-catalyzed allylic coupling of cucurbitacin B with boronic acids,providing a one-step approach to expand the chemical diversity of the C25 position.Our method was protecting-group-free,showing a good functional group tolerance and a wide substrate scope under mild reaction conditions.A library of 29 derivatives was prepared,compounds 2q and 2u showed higher cytotoxicity against A549 cells than cucurbitacin B,compounds 2n and 2o maintained potency,and the introduced hydroxyl and amino groups could be further derived.
