Heterodimerization of CXCR4 and CB2 Inhibits Prostate Cancer Cell Movement

CXCR4 和 CB2 的异二聚化抑制前列腺癌细胞运动

• 批准号: 8489689
• 负责人: Cimona V Hinton
• 金额: $ 29.45万
• 依托单位: CLARK ATLANTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8489689
• 关键词: AM 1241; Absence of pain sensation; Adverse effects; Affect; Agonist; Allergic Reaction; Animals; Apoptosis; Attenuated; Binding; CXCL12 gene; CXCR4 Receptors; CXCR4 gene; Cancer Control; Cannabinoids; Cell Culture Techniques; Cell Proliferation; Cells; Complement; Complex; Congenital Heart Defects; Coupled; Data; Development; Dimerization; Distal; Fc Receptor; Fluorescence Resonance Energy Transfer; GTP-Binding Proteins; Heterodimerization; Homo; Immune; Implant; In Vitro; Individual; Injection of therapeutic agent; Lead; Ligands; Limb structure; Luciferases; Malignant Neoplasms; Malignant neoplasm of cervix uteri; Malignant neoplasm of lung; Mediating; Metastatic Neoplasm to the Bone; Metastatic Prostate Cancer; Metastatic to; Modeling; Molecular; Movement; Mus; Neoplasm Metastasis; Organ; Organism; Pathway interactions; Prevention approach; Primary Neoplasm; Principal Investigator; Prostate; Prostatic Neoplasms; Proteins; Publishing; Reporting; Research Design; Signal Pathway; Signal Transduction; Stromal Cell-Derived Factor 1; Testing; Therapeutic; Tissues; base; bone; cancer cell; cancer therapy; cannabinoid receptor; cell motility; chemokine receptor; delta opioid receptor; desensitization; dimer; experience; in vivo; male; mouse model; neoplastic cell; neutralizing antibody; programs; prostate cancer cell; public health relevance; receptor; response; simulation; small hairpin RNA; tumor; tumor growth; tumor progression

DESCRIPTION (provided by applicant): Upon activation by stromal cell derived factor 1 alpha (SDF1 alpha), the G-protein-coupled chemokine receptor, CXCR4, generates signals that eventually lead to the metastatic spread and survival of primary tumor cells in distal organs. Indeed, elevated expression of CXCR4 protein in prostate tissues correlates with metastasis and overall prediction of poor survival. CXCR4 can form homodimers or can heterodimerize with unrelated receptors, such as the delta opioid receptor (DOR). Simultaneous treatment with appropriate agonists for the individual receptors that are heterodimerizing, such as the CXCR4/DOR heterodimer, results in a dimer that is unable to signal, although each receptor can bind its respective ligand. Therefore, heterodimerization can cause decreased signaling through such receptor complexes, representing functional desensitization. In the context of cancer treatment, CXCR4 signaling and subsequent functions can be silenced by desensitization through heterodimeric association with other receptors, thereby inhibiting CXCR4-generated signals that would otherwise lead to metastasis. Thus, antagonizing the function of CXCR4 through heterodimerization could be a rational approach to the prevention and management of metastatic prostate cancer, and could be an effective alternative to current therapeutics involving neutralizing antibodies or antagonists against CXCR4, both of which have undesirable consequences. Studies reported that simultaneous treatment with CXCR4 and cannabinoid receptor 2 (CB2R) agonists caused a reduction in CB2R-induced analgesia, suggesting a functional desensitization of CB2R, although dimerization was not analyzed. Given this scenario, a heterodimer of CXCR4/CB2R could potentially attenuate responses triggered individually by CXCR4 or CB2R, without the side effects experienced with the use of receptor antibodies or antagonists, especially in situations where both receptors are expressed on the same tumor cells. We will demonstrate that receptor heterodimerization could form the molecular basis for decreasing CXCR4-mediated signaling, and therefore, metastasis. Hypothesis: CXCR4 function can be abrogated by simultaneous ligand-dependent heterodimerization of CXCR4 with CB2R, resulting in decreased CXCR4 signaling, cell metastasis and overall tumor development. Specific aims: (1): To determine whether CXCR4 and CB2R physically associate in vitro; (2): To determine which signaling pathways are modulated as a result of heterodimerization of CXCR4 with CB2R; and (3): To determine whether heterodimerization of CXCR4 with CB2R antagonizes CXCR4-mediated metastasis in intact animals. Research design: Our strategy will include: (i) confirming that CXCR4 and CB2R dimerize by FRET analysis; (ii) determining whether CB2R is required as a dimer partner to abrogate signaling and known functions of CXCR4 by shRNA for CB2R; and (iii) examining whether heterodimerization of CXCR4 with CB2R will inhibit tumor growth and metastasis of prostate cancer cells to the bone in vivo.

描述（由申请人提供）：在被基质细胞衍生因子1 α (SDF1 α)激活后，g蛋白偶联趋化因子受体CXCR4产生信号，最终导致肿瘤细胞在远端器官的转移扩散和生存。事实上，前列腺组织中CXCR4蛋白的表达升高与转移和不良生存的总体预测相关。CXCR4可以形成同型二聚体，也可以与不相关的受体，如delta阿片受体（DOR）形成异源二聚体。同时用适当的激动剂治疗异源二聚体的个体受体，如CXCR4/DOR异源二聚体，导致二聚体无法发出信号，尽管每个受体都可以结合其各自的配体。因此，异源二聚化可以通过这种受体复合物导致信号传导减少，代表功能脱敏。在癌症治疗的背景下，CXCR4信号和随后的功能可以通过与其他受体的异源二聚体结合脱敏来沉默，从而抑制CXCR4产生的信号，否则会导致转移。因此，通过异源二聚化拮抗CXCR4的功能可能是预防和治疗转移性前列腺癌的一种合理方法，并且可能是目前涉及中和CXCR4抗体或拮抗剂的治疗方法的有效替代，这两种治疗方法都有不良后果。研究报道，CXCR4和大麻素受体2 （CB2R）激动剂同时治疗可导致CB2R诱导的镇痛减少，提示CB2R的功能性脱敏，尽管未分析二聚体作用。鉴于这种情况，CXCR4/CB2R的异源二聚体可能潜在地减弱CXCR4或CB2R单独触发的反应，而没有使用受体抗体或拮抗剂所经历的副作用，特别是在两种受体在同一肿瘤细胞上表达的情况下。我们将证明受体异二聚化可以形成减少cxcr4介导的信号传导的分子基础，因此，转移。