Molecular Effects of Bortezomib in Mantle Cell Lymphoma

硼替佐米对套细胞淋巴瘤的分子作用

• 批准号: 7969093
• 负责人: adrian u wiestner
• 金额: $ 56.66万
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7969093
• 关键词: Apoptosis; Apoptotic; Biological Markers; Bortezomib; Cell Death; Cell Line; Cells; Clinical Trials; Cyclin D1; Defect; Disease Progression; Disease Resistance; Dominant Genes; Drug resistance; Enzymes; Event; Gene Expression; Gene Expression Profile; Gene Expression Profiling; Genes; Heat shock proteins; Homeostasis; Lead; Lymphoma; Mantle Cell Lymphoma; Measures; Mediating; Molecular; Molecular Chaperones; Noxae; PMAIP1 gene; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phase II Clinical Trials; Physiological; Proteasome Inhibition; Proteasome Inhibitor; Proteins; Proto-Oncogene Proteins c-akt; RNA Interference; Regulation; Relative (related person); Resistance; Role; Sampling; Signal Transduction; Stress; Systems Biology; Tumor Biology; Up-Regulation; base; biological adaptation to stress; chemotherapy; drug mechanism; endoplasmic reticulum stress; improved; in vivo; multicatalytic endopeptidase complex; neoplastic cell; research clinical testing; resistance mechanism; response; transcription factor; treatment response

Mantle cell lymphoma (MCL), characterized by a t(11;14) translocation that results in up-regulation of cyclin D1, is incurable with standard chemotherapy. Several new drugs are currently undergoing early clinical testing in MCL. Recent phase II studies have shown that bortezomib (BZM), an inhibitor of the proteasome, can induce responses in about 50% of pre-treated patients. Bortezomib is more active against Mantle Cell Lymphoma than against most other lymphoma subtypes. Nevertheless, up to half of patients with MCL have bortezomib resistant disease. Factors contributing to intrinsic resistance to bortezomib have not been determined. We used a panel of 8 bortezomib sensitive and 3 relatively bortezomib resistant cell lines to investigate differences in tumor biology that could determine sensitivity to bortezomib. Bortezomib effectively inhibited high baseline proteasome activity and induced a comparable degree of proteasome inhibition in both sensitive and resistant cells. At 10nM bortezomib induced the pro-apoptotic BH3 only protein NOXA in sensitive but not resistant cells. However, at higher concentrations NOXA was upregulated in relative resistant cells and was sufficient to induce apoptosis arguing against a defect in NOXA regulation or function as the basis of bortezomib resistance. Bortezomib was equally effective against cells with high and low constitutive NF-B signaling. Also, sensitive and resistant MCL cell lines showed comparable activation of the AKT pathway. We conclude that bortezomib can overcome classic mechanisms of resistance to apoptosis and that determinants of bortezomib sensitivity in MCL are due to differences in signaling or stress pathways upstream of Noxa. To investigate the molecular effects of BZM on tumor biology in vivo we analyzed gene expression changes in patients with the leukemic form of MCL during treatment with BZM. Distinct functional gene expression signatures induced by BZM contained numerous genes encoding proteasome components, heat shock proteins, chaperones, detoxifying enzymes and pro-apoptotic factors. The dominant gene expression signatures were those driven by transcription factors that can mediate the endoplasmic reticulum (ER) stress response also known as the unfolded protein response. Under physiologic conditions, the ER stress response can help restore homeostasis and protect from apoptosis, while an overwhelming insult can lead to activation of pro-apoptotic mechanism. To define these effects in more detail, we used MCL cell lines characterized for their sensitivity to BZM. In these cell lines BZM induced the same gene expression signatures as observed in patient samples. Strong up-regulation of the ER-stress response was evident in BZM sensitive cells and correlated with induction of the pro-apoptotic BH3 only protein Noxa. Inhibition of Noxa up-regulation by RNAi protected cells from BZM induced apoptosis indicating that Noxa is a major effector mechanism of BZM induced cell death. Ongoing studies aim to identify the molecular basis for the observed variability in the activation of pro-apoptotic mechanisms by BZM.

套细胞淋巴瘤 (MCL) 的特点是 t(11;14) 易位导致细胞周期蛋白 D1 上调，标准化疗无法治愈。 目前有几种新药正在进行 MCL 的早期临床测试。 最近的 II 期研究表明，蛋白酶体抑制剂硼替佐米 (BZM) 可以在约 50% 的接受过治疗的患者中诱导缓解。 硼替佐米对套细胞淋巴瘤的活性比对大多数其他淋巴瘤亚型的活性更强。 然而，多达一半的 MCL 患者患有硼替佐米耐药性疾病。 导致硼替佐米内在耐药性的因素尚未确定。 我们使用一组 8 个硼替佐米敏感细胞系和 3 个相对硼替佐米耐药细胞系来研究可以确定对硼替佐米敏感性的肿瘤生物学差异。 硼替佐米有效抑制高基线蛋白酶体活性，并在敏感细胞和耐药细胞中诱导相当程度的蛋白酶体抑制。 10nM 硼替佐米在敏感但不耐药的细胞中诱导促凋亡 BH3 蛋白 NOXA。 然而，在较高浓度下，NOXA 在相对耐药的细胞中上调，并足以诱导细胞凋亡，反对 NOXA 调节或功能缺陷作为硼替佐米耐药的基础。 硼替佐米对具有高和低组成型 NF-B 信号传导的细胞同样有效。 此外，敏感和耐药 MCL 细胞系显示出类似的 AKT 通路激活。 我们的结论是，硼替佐米可以克服抗细胞凋亡的经典机制，并且 MCL 中硼替佐米敏感性的决定因素是由于 Noxa 上游信号或应激途径的差异。 为了研究 BZM 对体内肿瘤生物学的分子影响，我们分析了 MCL 白血病患者在 BZM 治疗期间的基因表达变化。 BZM 诱导的独特功能基因表达特征包含许多编码蛋白酶体成分、热休克蛋白、分子伴侣、解毒酶和促凋亡因子的基因。 显性基因表达特征是由转录因子驱动的，这些转录因子可以介导内质网（ER）应激反应，也称为未折叠蛋白反应。 在生理条件下，内质网应激反应可以帮助恢复体内平衡并防止细胞凋亡，而压倒性的损伤可以导致促凋亡机制的激活。 为了更详细地定义这些效应，我们使用了对 BZM 敏感的 MCL 细胞系。 在这些细胞系中，BZM 诱导了与患者样本中观察到的相同的基因表达特征。 BZM 敏感细胞中 ER 应激反应的强烈上调是明显的，并且与促凋亡 BH3 蛋白 Noxa 的诱导相关。 RNAi 抑制 Noxa 上调可保护细胞免受 BZM 诱导的细胞凋亡，表明 Noxa 是 BZM 诱导的细胞死亡的主要效应机制。正在进行的研究旨在确定 BZM 激活促凋亡机制中观察到的变异性的分子基础。