• Ca

      Wong, Vincent K-W.; Qiu, Congling; Xu, Su-Wei; Law, Betty Yuen Kwan; Zeng, Wu; Wang, Hui; Michelangeli, Francesco; Dias, Ivo Ricardo De Seabra Rodrigues; Qu, Yuan Qing; Chan, Tsz Wai; et al. (2019-05-23)
      Celastrol exhibits anti-arthritic effect in rheumatoid arthritis (RA), but the role of celastrol-mediated Ca mobilization in treatment of RA remains unelucidated. Here, we illustrate the regulatory role of celastrol-induced Ca signalling in synovial fibroblasts of RA patients and adjuvant-induced arthritis (AIA) in rats. Molecular target of celastrol was determined by computational docking, Ca dynamic and functional assays on SERCA. Ca -mediated autophagy in RASFs/RAFLS and the underlying mechanism were verified by quantification of endogenous LC3-II puncta, immunoblotting, and flow cytometry with the Ca chelator (BAPTA/AM) or suitable inhibitors. The anti-arthritic effect of celastrol, autophagy induction and growth rate of synovial fibroblasts in AIA rats were monitored by microCT and immunofluorescence staining. mRNA from joint tissues of AIA rats was isolated for transcriptional analysis of inflammatory genes. The role of Ca in regulating the identified genes was investigated by knockdown of calmodulin, calpains, and calcineurin. Celastrol inhibited SERCA to induce autophagy-dependent cytotoxicity in RASFs/RAFLS via CaMKKβ-AMPK-mTOR pathway and repressed arthritis symptoms in AIA rats. BAPTA/AM hampered the in vitro and in vivo effectiveness of celastrol. Inflammatory- and autoimmunity-associated genes downregulated by celastrol in joint tissues of AIA rat were restored by BAPTA/AM. Knockdown of calmodulin, calpains, and calcineurin in RAFLS confirmed the role of Ca in celastrol-regulated gene expression. Celastrol triggered Ca signalling to induce autophagic cell death in RASFs/RAFLS and ameliorated arthritis in AIA rats mediated by calcium-dependent/-binding proteins facilitating the exploitation of anti-arthritic drugs based on manipulation of Ca signalling. [Abstract copyright: This article is protected by copyright. All rights reserved.]
    • (Z)3,4,5,4'-trans-tetramethoxystilbene, a new analogue of resveratrol, inhibits gefitinb-resistant non-small cell lung cancer via selectively elevating intracellular calcium level.

      Fan, Xing-Xing; Yao, Xiao-Jun; Xu, Su-Wei; Wong, Vincent K-W.; He, Jian-Xing; Ding, Jian; Xue, Wei-Wei; Mujtaba, Tahira; Michelangeli, Francesco; Huang, Min; et al. (Nature Publishing Group, 2015-11-06)
      Calcium is a second messenger which is required for regulation of many cellular processes. However, excessive elevation or prolonged activation of calcium signaling would lead to cell death. As such, selectively regulating calcium signaling could be an alternative approach for anti-cancer therapy. Recently, we have identified an effective analogue of resveratrol, (Z)3,4,5,4′-trans-tetramethoxystilbene (TMS) which selectively elevated the intracellular calcium level in gefitinib-resistant (G-R) non-small-cell lung cancer (NSCLC) cells. TMS exhibited significant inhibitory effect on G-R NSCLC cells, but not other NSCLC cells and normal lung epithelial cells. The phosphorylation and activation of EGFR were inhibited by TMS in G-R cells. TMS induced caspase-independent apoptosis and autophagy by directly binding to SERCA and causing endoplasmic reticulum (ER) stress and AMPK activation. Proteomics analysis also further confirmed that mTOR pathway, which is the downstream of AMPK, was significantly suppressed by TMS. JNK, the cross-linker of ER stress and mTOR pathway was significantly activated by TMS. In addition, the inhibition of JNK activation can partially block the effect of TMS. Taken together, TMS showed promising anti-cancer activity by mediating calcium signaling pathway and inducing apoptosis as well as autophagy in G-R NSCLC cells, providing strategy in designing multi-targeting drug for treating G-R patients.