Targeting GRP78/BIP As An Adjunct Therapy For EGFR-positive Breast Cancer

靶向 GRP78/BIP 作为 EGFR 阳性乳腺癌的辅助治疗

• 批准号: 7611672
• 负责人: Marina V Backer
• 金额: $ 24.58万
• 依托单位: SIBTECH, INC.
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-17 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7611672
• 关键词: Address; Animal Model; Animals; Bacterial Toxins; Breast Cancer Cell; Breast Cancer Model; Breast Cancer Treatment; Catalytic Domain; Cell Survival; Cells; Characteristics; Chimeric Proteins; Cleaved cell; Clinical; Combined Modality Therapy; Critiques; Cytotoxin; Data; Development; Diphtheria Toxin; Doxorubicin; Drug resistance; EGF gene; Endopeptidases; Epidermal Growth Factor; Epidermal Growth Factor Receptor; Evaluation; Failure; Fc Receptor; Goals; Guanosine Monophosphate; Human; Immunity; Inhibitory Concentration 50; Lead; Mammalian Cell; Mammary Neoplasms; Modeling; Mus; Names; Numbers; Penetration; Peptide Hydrolases; Pharmaceutical Preparations; Phase; Phase I Clinical Trials; Production; Protein Overexpression; Proteins; Public Health; Purpose; Range; Recurrent disease; Relative (related person); Research; Resistance; Role; Safety; Side; Site; Stress; Testing; Therapeutic; Thinking; Toxic effect; Toxicology; Toxin; Treatment Protocols; base; cancer cell; cell growth; chemotherapy; experience; immunogenicity; in vivo; inhibitor/antagonist; malignant breast neoplasm; mouse model; neoplastic cell; novel; outcome forecast; protein misfolding; receptor expression; research study; response; targeted delivery; tissue culture; tumor; tumor growth; tumor progression

DESCRIPTION (provided by applicant): Drug-resistant breast cancer cells are the main cause of recurrent disease. One mechanism of cancer cell survival and drug resistance is mobilization of GRP78/BiP, master-regulator of unfolded protein response and ER stress. Because of its role, GRP78/BiP is considered as a novel predictor of responsiveness to chemotherapy in breast cancer. We hypothesize that targeted destruction of GRP78/BiP in breast cancer cells would increase the efficacy of approved chemotherapeutic drugs. To test this hypothesis, we constructed a fusion protein comprising human epidermal growth factor (EGF) and SLiP, a catalytic subunit of a novel bacterial toxin SubAB, whose unique and the only substrate is GRP78/BiP. Our preliminary results indicate that in EGFR-positive cells, EGF-SLiP cleaves GRP78/BiP and inhibits cell growth at picomolar concentrations. Critically for this project, doxorubicin-resistant cancer cells display greater sensitivity to EGF-SLiP than parental cells. Since EGFR overexpression is also associated with increased drug resistance of breast cancer cells, we expect that targeting SLiP via EGFR would be especially beneficial. We also expect that the mechanism-based complementarity between EGF-SliP and chemotherapeutic drugs, as well as the absence of pre-existing immunity against SLiP, will provide EGF-SLiP with distinct advantages relative to previous unsuccessful EGF-based cytotoxins. In response to critique of the original proposal and in view of the new data, we redesigned the proposal and focused exclusively on animal studies in an orthotopic breast cancer model. The key questions regarding potential utility of EGF-SLiP for treatment of breast cancer will be explored in this project: 1) tumor penetration and GRP78/BiP cleavage, 2) systemic toxicity and immunogenicity, and 3) efficacy of combination with doxorubicin for treatment of doxorubicin- resistant tumors. In response to the critique of the resubmission we explain in more details the master regulator role of BiP which allows EGF-SLiP to act synergistically with various insults and add additional data. Successful completion of Phase I of this project will provide critical information on key EGF- SLiP characteristics in vivo. We expect that the results of Phase I will be sufficient for rational decision on feasibility of clinical development of EGF-SLiP. Phase II of this project will include side-by-side comparison with existing EGFR-directed drugs, formal toxicology, GMP- production, and transition to Phase I clinical trials. PUBLIC HEALTH RELEVANCE: We propose to test the feasibility of using a new cytotoxin, EGF-SLiP for targeting drug-resistant cells in the course of chemotherapy of breast cancer. The toxic part of the cytotoxin, SLiP, is a recently characterized bacterial protease that cleaves only one protein in mammalian cells, GRP78/BiP, which controls cellular defenses against chemotherapeutic drugs and is a novel predictor of resistance to chemotherapy of breast cancer. EGF-SLiP targets cytotoxin to breast cancer cells that express EGF receptors, a feature that is also implicated in cancer progression and drug resistance. Using orthotopic mouse model of breast cancer, we will establish efficacy of EGF-SLiP in cleaving GRP78/BiP in tumors, assess systemic toxicity and immunogenicity, and establish its efficacy as part of a combination regimen in treating doxorubicin-resistant tumor. We expect that this data establish feasibility of clinical development for EGF-SLiP.

描述（由申请人提供）：耐药性乳腺癌细胞是复发性疾病的主要原因。癌细胞存活和耐药性的一种机制是动员GRP78/BIP，这是展开的蛋白质反应和ER应激的主调节剂。由于其作用，GRP78/BIP被认为是对乳腺癌化学疗法反应性的新预测指标。我们假设有针对性地破坏GRP78/BIP在乳腺癌细胞中会增加认可的化学治疗药物的功效。为了检验这一假设，我们构建了一个包含人表皮生长因子（EGF）和Slip的融合蛋白，这是一种新型细菌毒素Subab的催化亚基，其独特和唯一的底物是GRP78/BIP。我们的初步结果表明，在EGFR阳性细胞中，EGF-SLIP裂解GRP78/BIP，并抑制皮摩尔浓度下的细胞生长。对于该项目，耐霉素抗性癌细胞对EGF滑移的敏感性比亲本细胞更大。由于EGFR的过表达也与乳腺癌细胞的耐药性升高有关，因此我们预计通过EGFR靶向滑移特别有益。我们还期望EGF-SLIP和化学治疗药物之间基于机制的互补性，以及缺乏对滑移的预先存在免疫力，将提供EGF-SLIP，相对于先前的不成功EGF基于EGF的细胞毒素，EGF-SLIP具有明显的优势。为了响应对原始建议和新数据的批评，我们重新设计了该提案，并专注于原位乳腺癌模型中的动物研究。该项目将探讨有关EGF-SPLIP治疗乳腺癌的潜在用途的关键问题：1）肿瘤渗透和GRP78/BIP裂解，2）全身毒性和免疫原性，以及3）与阿霉素结合治疗女耐纤维蛋白抵抗肿瘤的功效。为了回应对重新提交的批评，我们在更多详细信息中解释了BIP的主调节器角色，该角色允许EGF-SLIP通过各种侮辱协同行动并添加其他数据。该项目的第一阶段的成功完成将提供有关体内关键EGF-滑动特征的关键信息。我们预计，第一阶段的结果将足以合理地决定EGF-SLIP临床发展的可行性。该项目的第二阶段将包括与现有的EGFR指导药物，正式毒理学，GMP生产以及过渡到I期临床试验的并排比较。公共卫生相关性：我们建议测试在乳腺癌化学疗法过程中使用新的细胞毒素，EGF-SLIP来靶向耐药细胞的可行性。细胞毒素Slip的有毒部分是最近表征的细菌蛋白酶，仅在哺乳动物细胞中切割一种蛋白GRP78/BIP，它控制了针对化学治疗药物的细胞防御措施，并且是对乳腺癌化学疗法抗性的新预测指标。 EGF-SLIP将细胞毒素靶向表达EGF受体的乳腺癌细胞，该特征也与癌症进展和耐药性有关。使用乳腺癌的原位小鼠模型，我们将在肿瘤中裂解GRP78/BIP，评估全身毒性和免疫原性，并确立其作为治疗阿霉素耐药性肿瘤的组合方案的一部分。我们预计该数据可以确定临床发展的EGF-SLIP的可行性。