Autoantibodies to tumor-derived neoepitopes as biomarkers and immunoPET agents for the early detection of small cell lung cancer

项目总结/摘要 小细胞肺癌（SCLC）每年杀死超过30，000名美国人，并且总体上有令人沮丧的5年 存活率低于7%。然而，通过早期发现和干预，SCLC的结果大大改善， 早期诊断的患者5年生存率接近50%。这些不一致的结果 这表明，到目前为止，大多数SCLC病例是在肿瘤迅速变得 对治疗有抵抗力很快就会死亡因此，有效的早期检测策略是必要的， 既能识别高危人群的癌症，又能促进非侵入性成像， 小肿瘤，以指导手术切除和治疗。我们已经发现，自身抗体（AAb）存在于 基本上所有SCLC患者的血浆（比其他主要癌症更常见），并已验证 至少7种由SCLC肿瘤表达的AAb鉴定的新抗原，其可以作为高度癌症特异性的 早期检测生物标志物和/或成像靶。我们设想一个早期检测/诊断平台， 在推荐的年度低剂量计算机断层扫描（LD-CT）肺癌筛查期间， 吸烟者。然而，LD-CT和所有目前的成像方式不适合SCLC的早期检测，即使在 由于低于所需的敏感性/特异性和风险/获益分析，吸烟人群富集。在这里， 我们提出了一个两层的方法，通过血液测试检测小细胞肺癌特异性AAb的存在， 将触发利用放射免疫缀合物的免疫正电子发射断层扫描（immunoPET 其特异性靶向仅在SCLC肿瘤上表达的自身抗原蛋白。验血可以确保 仅筛查高危个体，免疫PET确认并定位肿瘤，以便将来治疗。 因此，在目的1中，我们提出确定SCLC特异性自身抗原（AAg）的作用，分离人B细胞特异性抗原，并将其与SCLC特异性自身抗原结合。 检测AAg作为高度敏感和特异的早期检测生物标志物，并对AAb进行测序 可变区，并将其克隆到表达载体中以产生人单克隆重组抗体 用于成像目的。在目标2中，我们提出使用荧光团和荧光素对SCLC肿瘤进行免疫成像。 放射性核素标记的AAb免疫缀合物对这些癌症靶向新抗原/表位具有特异性。 我们迄今为止测试的2种抗体的初步数据显示，它们特异性结合SCLC肿瘤， 在临床前模型中，强调了整个管道的可行性。综上所述，我们将联合收割机AAb-AAg 通过免疫PET成像进行风险分层的早期检测，以确认和定位肿瘤，从而建立 一种能够降低这种高度侵袭性癌症死亡率的早期检测途径。

Project Summary/Abstract Small-cell lung cancer (SCLC) kills over 30,000 Americans every year and has a dismal 5-year overall survival rate of less than 7%. However, SCLC outcomes are greatly improved by early detection and intervention, with a nearly 50% 5-year survival rate for patients diagnosed at an early stage. These discrepant outcomes indicate that, by far, the majority of SCLC cases are diagnosed at later stages at which tumors rapidly become resistant to therapy, with death quickly following. Thus, an effective early detection strategy is necessary that both identifies cancer in people at high risk and facilitates non-invasive imaging that can confirm and delineate small tumors to guide surgical resection and treatment. We have found that autoantibodies (AAb) are present in the plasma of essentially all SCLC patients (much more common than in other major cancers) and have validated at least 7 AAb-identified neoantigens expressed by SCLC tumors that can be exploited as highly cancer-specific early detection biomarkers and/or imaging targets. We envision an early detection/diagnosis platform performed during the recommended annual low-dose computed tomography (LD-CT) lung cancer screenings for heavy smokers. However, LD-CT and all current imaging modalities are not suitable for SCLC early detection even in smoking enriched populations due to lower than required sensitivity/specificity and risk/benefit analyses. Here, we propose a two-tiered approach, with a blood test that detects the presence of AAb specific for SCLC that would trigger immuno-positron emission tomography (immunoPET) imaging utilizing a radioimmunoconjugate that specifically targets the autoantigenic proteins expressed only on SCLC tumors. The blood test ensures that only high-risk individuals are screened and the immunoPET confirms and localizes the tumor for future treatment. Thus, in Aim 1, we propose to define the role of SCLC-specific autoantigens (AAg), isolate human B cells specific to the AAg, test the AAg as highly sensitive and specific early detection biomarkers, and sequence the AAb variable regions and clone them into expression vectors to produce human monoclonal recombinant antibodies for imaging purposes. In Aim 2, we propose to perform immunoimaging of SCLC tumors using fluorophore- and radionuclide-labeled AAb immunoconjugates specific for these cancer targeted neoantigens/epitopes. Preliminary data for the 2 antibodies that we have tested so far show that they specifically bind to SCLC tumors in preclinical models, underscoring the feasibility of the entire pipeline. In summary, we will combine AAb-AAg early detection for risk stratification with immunoPET imaging to confirm and localize tumors, thereby establishing an early detection pathway capable of reducing the mortality of this highly aggressive cancer.