Development of diagnositic and therapeutic methods using frameshift mutated peptides for colorectal cancers with microsatellite instability

使用移码突变肽开发微卫星不稳定性结直肠癌的诊断和治疗方法

基本信息

批准号：
12557109
负责人：
KAWAKAMI Yutaka
金额：
$ 8.45万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Microsatellite instability positive colorectal cancers (MSI+CRC) caused by malfunction of DNA mismatch repair has unique characteristics including good prognosis with T-cell infiltrates, suggesting immune responses against tumor specific peptides generated by frameshift mutations. In this study, we have attempted to identify tumor antigens involved in MSI+CRC. We first applied SEREX to identify tumor antigens that induced IgG in MSI+CRC patients, then, immunogenicity of the antigens was evaluated by detecting IgG among sera from various cancer patients and healthy individuals. 150 antigens including 75 antigens for that IgG were detected only in MSI+CRC patients, were identified. The frameshift mutation in the repetitive sequence in the isolated CDX2 antigen was found in the tumor tissue of the patient with antrCDX2 antibody. Using recombinant frameshift CDX2 proteins, the antibody was found to recognize the C-terminal unique peptide caused by the frameshift mutation. This antibody was disappeared 7 years after the curative resection, suggesting that the immune responses may be useful as tumor markers. Although in vitro induction of T-cells specific for the mutated CDX2 was attempted, specific T cells were not induced possibly because of the use of lymphocytes from the 7 year disease free patient. We have also evaluated whether IgG were detected against possible frameshift peptides from the known MSI target genes. However, no IgG was detected against any recombinant peptides tested. In summary, we demonstrated for the first time that tumor specific immune response against the frameshift peptides caused by MSI could be induced in MSI+CRC patients. These tumor specific mutated peptides may be useful for the development of diagnostic and therapeutic methods for patients with MSI+ CRC. SEREX using autologous tumors and analysis of immune responses against the frameshift peptides using patient's T-cells should be performed in the further study.

由DNA不匹配维修故障引起的微卫星不稳定性阳性结直肠癌（MSI+CRC）具有独特的特征，包括对T细胞浸润的良好预后，表明对frameshift突变产生的肿瘤特异性肽的免疫反应。在这项研究中，我们试图鉴定与MSI+CRC有关的肿瘤抗原。我们首先应用了SEREX来鉴定在MSI+CRC患者中诱导IgG的肿瘤抗原，然后，通过检测来自各种癌症患者和健康个体的血清中的IgG来评估抗原的免疫原性。仅在MSI+CRC患者中检测到150种包括75种IgG的抗原。在AntrCDX2抗体的患者的肿瘤组织中发现了分离的CDX2抗原中重复序列中的移码突变。使用重组射击CDX2蛋白，发现该抗体识别由移除突变引起的C末端独特肽。治疗切除术后7年消失了该抗体，这表明免疫反应可能可作为肿瘤标记物有用。尽管尝试在体外诱导针对突变的CDX2特异性的T细胞，但由于使用了无7年无疾病患者的淋巴细胞，因此未诱导特定的T细胞。我们还评估了是否检测到来自已知MSI靶基因的可能的移状肽的IgG。但是，针对测试的任何重组肽检测到IgG。总而言之，我们首次证明了MSI+CRC患者可以诱导肿瘤特异性免疫反应针对由MSI引起的移状肽。这些肿瘤特异性突变肽可能有助于开发MSI+ CRC患者的诊断和治疗方法。在进一步的研究中，应使用自体肿瘤的SEREX使用自体肿瘤分析使用患者的T细胞对移状肽的免疫反应。