Brusa Davide, Garetto Stefano, Chiorino Giovanna, Scatolini Maria, Migliore Elisa, Camussi Giovanni, Matera Lina
Laboratory of Tumor Immunology, Department of Internal Medicine, University of Turin, Turin, Italy.
Vaccine. 2008 Nov 25;26(50):6422-32. doi: 10.1016/j.vaccine.2008.08.063. Epub 2008 Oct 9.
Critical issues for cytotoxic lymphocyte (CTL) cross-priming are (a) the maturation state of dendritic cells (DC), (b) the source of the tumor-associated antigens (TAA) and (c) the context in which they are delivered to DCs. Drug-induced apoptosis has recently been implicated in CTL cross-priming. However, since drug-treatment produces in vivo more tumor cells than the DC default apoptotic clearance program can cope with, they are expected to proceed to secondary necrosis and change their molecular pattern. Here we have addressed this issue on renal carcinoma cells (RCC) by using different apoptotic stimuli. UVC, but not gamma-irradiation or anthracyclins, induced after 4h treatment of the RCC cell line K1 a combination of apoptotic (phosphatydilserine and calreticulin plasma membrane mobilization) and necrotic (membrane incompetence) features. Heat shock protein (Hsp)-70 and chromatin-bound high mobility box 1 HMGB1 protein, typical of necrosis, were released during the further 20h and thus made accessible to co-cultured monocyte-derived immature (i) DC. UVC-treated, secondary necrotic RCC cell lines were cross-presented with higher efficiency by cytokine-matured (m) DC than their early apoptotic (i.e. gamma-irradiated) counterpart. Upstream events such as increased tumor uptake, activation of genes involved in the antigen-processing machinery, and increased expression of costimulatory and maturation molecules were also observed after loading iDC with secondary necrotic, but not apoptotic, tumor cells. These data offer a description of the molecular and immunogenic characteristics of post-apoptotic tumors which can be exploited to increase the efficiency of in vivo and ex vivo TAA delivery to the DC cross-presentation pathway.
细胞毒性淋巴细胞（CTL）交叉启动的关键问题包括：（a）树突状细胞（DC）的成熟状态；（b）肿瘤相关抗原（TAA）的来源；以及（c）将它们递送至DC的背景。药物诱导的凋亡最近与CTL交叉启动有关。然而，由于药物治疗在体内产生的肿瘤细胞比DC默认的凋亡清除程序所能处理的更多，预计它们会进入继发性坏死并改变其分子模式。在这里，我们通过使用不同的凋亡刺激来研究肾癌细胞（RCC）的这个问题。对RCC细胞系K1进行4小时处理后，紫外线C（UVC）而非γ射线照射或蒽环类药物诱导了凋亡（磷脂酰丝氨酸和钙网蛋白质膜动员）和坏死（膜功能障碍）特征的组合。热休克蛋白（Hsp）-70和与染色质结合的高迁移率族蛋白盒1（HMGB1）蛋白（坏死的典型特征）在接下来的20小时内释放，从而使共培养的单核细胞衍生的未成熟（i）DC能够接触到。与早期凋亡（即γ射线照射）的对应物相比，细胞因子成熟的（m）DC对UVC处理的继发性坏死RCC细胞系的交叉呈递效率更高。在用继发性坏死而非凋亡的肿瘤细胞负载iDC后，还观察到了诸如肿瘤摄取增加、参与抗原加工机制的基因激活以及共刺激和成熟分子表达增加等上游事件。这些数据描述了凋亡后肿瘤的分子和免疫原性特征，可用于提高体内和体外将TAA递送至DC交叉呈递途径的效率。
