Authors' Affiliations: Department of Microbiology and Immunology, Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina; Levine Cancer Institute, Charlotte, North Carolina; Department of Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York; and The University of Texas MD Anderson Cancer Center, Texas.
Clin Cancer Res. 2013 Nov 15;19(22):6242-51. doi: 10.1158/1078-0432.CCR-13-2083. Epub 2013 Sep 27.
gp96 (grp94) is a key downstream chaperone in the endoplasmic reticulum (ER) to mediate unfolded protein response (UPR) and the pathogenesis of multiple myeloma is closely linked to dysregulated UPR. In this study, we aimed to determine the roles of gp96 in the initiation and progression of multiple myeloma in vivo and in vitro.
We generated a mouse model with overexpression of XBP1s and conditional deletion of gp96 in B-cell compartment simultaneously to identify the roles of gp96 in the development of multiple myeloma in vivo. Using a short hairpin RNA (shRNA) system, we silenced gp96 in multiple human multiple myeloma cells and examined the effect of gp96 knockdown on multiple myeloma cells by cell proliferation, cell-cycle analysis, apoptosis assay, immunohistochemistry, and human myeloma xenograft model. The anticancer activity of gp96 selective inhibitor, WS13, was evaluated by apoptosis assay and MTT assay.
Genetic deletion of gp96 in XBP1s-Tg mice attenuates multiple myeloma. Silencing of gp96 causes severe compromise in human multiple myeloma cell growth through inhibiting Wnt-LRP-survivin pathway. We also confirmed that knockdown of gp96 decreased human multiple myeloma growth in a murine xenograft model. The targeted gp96 inhibitor induced apoptosis and blocked multiple myeloma cell growth, but did not induce apoptosis in pre-B leukemic cells. We have demonstrated that myeloma growth is dependent on gp96 both genetically and pharmacologically.
gp96 is essential for multiple myeloma cell proliferation and survival, suggesting that gp96 is a novel therapeutic target for multiple myeloma. Clin Cancer Res; 19(22); 6242-51. ©2013 AACR.
gp96（grp94）是内质网（ER）中未折叠蛋白反应（UPR）的关键下游伴侣，多发性骨髓瘤的发病机制与 UP 失调密切相关。本研究旨在确定 gp96 在体内和体外多发性骨髓瘤发病机制中的作用。
我们构建了一个同时过表达 XBP1s 和条件性缺失 B 细胞 gp96 的小鼠模型，以鉴定 gp96 在体内多发性骨髓瘤发生发展中的作用。我们利用短发夹 RNA（shRNA）系统沉默多个人类多发性骨髓瘤细胞中的 gp96，并通过细胞增殖、细胞周期分析、凋亡测定、免疫组织化学和人骨髓瘤异种移植模型检测 gp96 敲低对多发性骨髓瘤细胞的影响。通过凋亡测定和 MTT 测定评估 gp96 选择性抑制剂 WS13 的抗癌活性。
XBP1s-Tg 小鼠中 gp96 的基因缺失可减轻多发性骨髓瘤。gp96 的沉默通过抑制 Wnt-LRP-survivin 通路严重损害人类多发性骨髓瘤细胞的生长。我们还证实，gp96 的敲低降低了人多发性骨髓瘤在小鼠异种移植模型中的生长。靶向 gp96 抑制剂诱导凋亡并阻断多发性骨髓瘤细胞生长，但不会诱导前 B 白血病细胞凋亡。我们已经证明，gp96 在遗传和药理学上均对多发性骨髓瘤细胞的增殖和存活至关重要，这表明 gp96 是多发性骨髓瘤的一个新的治疗靶点。
临床癌症研究；19（22）；6242-51。©2013AACR。
