Vaccine and radiation for the therapy of human cancers

使用螯合放射性核素(Sm-153-EDTMP)调节肿瘤细胞的表型和增强T细胞介导的杀伤。将肿瘤细胞暴露于亚致死剂量的外照射可上调肿瘤抗原和辅助分子的表达，使肿瘤细胞更容易受到抗原特异性细胞毒性T淋巴细胞(CTL)的杀伤。该项目探索了一种可能性，即暴露于姑息性剂量的放射性药物可以改变肿瘤细胞的表型，使它们更容易受到T细胞介导的杀伤。在这里，10个人类肿瘤细胞系(4个前列腺，2个乳腺和4个肺)暴露在剂量增加的放射性药物samarium-153-ethylenediaminetetramethylenephosphonate(153Sm-EDTMP)中，该药物用于癌症患者治疗骨转移引起的疼痛。对前列腺癌相关的5种表面分子和几种肿瘤相关抗原的表达进行了荧光激活细胞分选分析和实时定量聚合酶链式反应(PCR)分析。将人前列腺癌LNCaP细胞暴露于153Sm-EDTMP，并与肿瘤相关抗原特异性CTL孵育，进行CTL杀伤实验，以确定暴露于153Sm-EDTMP是否使LNCaP细胞对T细胞介导的杀伤更敏感。153Sm-EDTMP使肿瘤细胞表面分子Fas(100%上调Fas)、癌胚抗原(90%)、粘蛋白-1(60%)、主要组织相容性复合体(MHC)I类(50%)和细胞间黏附分子-1(40%)表达上调。实时定量聚合酶链式反应分析揭示了更多上调的肿瘤抗原。暴露于153Sm-EDTMP使LNCaP细胞更容易受到前列腺特异性抗原、癌胚抗原(CEA)和粘蛋白-1特异性CTL的杀伤。153Sm-EDTMP相当于骨内姑息性给药的剂量改变了肿瘤细胞的表型，提示153Sm-EDTMP可能与免疫治疗协同作用，增加肿瘤细胞对CTL杀伤的敏感性。使用放射性标记的单抗增强疫苗介导的T细胞反应。放射性标记的单抗(MAb)在血液系统恶性肿瘤中显示出明显的抗肿瘤作用。对于实体瘤来说，这一结果更难实现，因为很大程度上是因为难以将足够数量的单抗输送到肿瘤块中。以前的研究表明，非溶解水平的外部射线照射会使肿瘤细胞更容易受到T细胞介导的杀伤。这些研究的目的是确定选择性地向肿瘤递送放射性标记单抗是否会调节肿瘤细胞的表型，从而增强疫苗介导的T细胞杀伤。在这里，将转人CEA基因的小鼠移植到表达CEA的小鼠癌细胞系中。放射免疫治疗由Y-90标记的抗CEA单抗组成，可单独使用或与疫苗治疗联合使用。单剂量Y-90标记的抗CEA单抗与疫苗治疗相结合，与疫苗或单抗相比，在统计上显著增加了荷瘤小鼠的存活率；这被证明是通过参与Fas/Fas配体途径而实现的。与单独接种疫苗相比，接受联合治疗的小鼠的CEA特异性CD8+T细胞的活性百分比也显著增加。治愈肿瘤的小鼠表现出一种抗原级联反应，导致CD4+和CD8+T细胞不仅对CEA，而且对p53和gp70产生反应。这些发现表明，以放射性标记单抗的形式进行的全身放射治疗，与疫苗相结合，可以促进有效的抗肿瘤反应，这可能对未来临床试验的设计有一定的意义。

The use of chelated radionuclide (Samarium-153-EDTMP) to modulate phenotype of tumor cells and enhance T-cell-mediated killing. Exposing human tumor cells to sublethal doses of external beam radiation upregulates expression of tumor antigen and accessory molecules, rendering tumor cells more susceptible to killing by antigen-specific cytotoxic T lymphocytes (CTLs). This project explored the possibility that exposure to palliative doses of a radiopharmaceutical agent could alter the phenotype of tumor cells to render them more susceptible to T-ell-mediated killing. Here, 10 human tumor cell lines (4 prostate, 2 breast, and 4 lung) were exposed to increasing doses of the radiopharmaceutical samarium-153-ethylenediaminetetramethylenephosphonate (153Sm-EDTMP) used in cancer patients to treat pain due to bone metastasis. Fluorescence-activated cell sorting analysis and quantitative real-time polymerase chain reaction (PCR) analysis for expression of five surface molecules and several tumor-associated antigens involved in prostate cancer were done. LNCaP human prostate cancer cells were exposed to153Sm-EDTMPand incubated with tumor-associated antigen-specific CTL in a CTL killing assay to determine whether exposure to 153Sm-EDTMP rendered LNCaP cells more susceptible to T-cell-mediated killing. Tumor cells up-regulated the surface molecules Fas (100% of cell lines upregulated Fas), carcinoembryonic antigen (90%), mucin-1 (60%), major histocompatibility complex (MHC) class I (50%), and intercellular adhesion molecule-1 (40%) in response to 153Sm-EDTMP. Quantitative real-time PCR analysis revealed additional upregulated tumor antigens. Exposure to 153Sm-EDTMP rendered LNCaP cells more susceptible to killing by CTLs specific for prostate-specific antigen, carcinoembryonic antigen (CEA), and mucin-1. Doses of 153Sm-EDTMP equivalent to palliative doses delivered to bone alter the phenotype of tumor cells, suggesting that 153Sm-EDTMP may work synergistically with immunotherapy to increase the susceptibility of tumor cells to CTL killing. The use of radiolabeled monoclonal antibody to enhance vaccine-mediated T-cell responses. Radiolabeled monoclonal antibodies (mAb) have demonstrated measurable antitumor effects in hematologic malignancies. This outcome has been more difficult to achieve for solid tumors due, for the most part, to difficulties in delivering sufficient quantities of mAb to the tumor mass. Previous studies have shown that nonlytic levels of external beam radiation can render tumor cells more susceptible to T cell-mediated killing. The goal of these studies was to determine if the selective delivery of a radiolabeled mAb to tumors would modulate tumor cell phenotype so as to enhance vaccine-mediated T-cell killing. Here, mice transgenic for human CEA were transplanted with a CEA expressing murine carcinoma cell line. Radioimmunotherapy consisted of yttrium-90 (Y-90)-labeled anti-CEA mAb, used either alone or in combination with vaccine therapy. A single dose of Y-90-labeled anti-CEA mAb, in combination with vaccine therapy, resulted in a statistically significant increase in survival in tumor-bearing mice over vaccine or mAb alone; this was shown to be mediated by engagement of the Fas/Fas ligand pathway. Mice receiving the combination therapy also showed a significant increase in the percentage of viable tumor-infiltrating CEA-specific CD8+ T cells compared to vaccine alone. Mice cured of tumors demonstrated an antigen cascade resulting in CD4+ and CD8+ T-cell responses not only for CEA, but for p53 and gp70. These findings show that systemic radiotherapy in the form of radiolabeled mAb, in combination with vaccine, promotes effective antitumor response, which may have implications in the design of future clinical trials.