A new epithelial cell subpopulation predicts response to surgery, chemotherapy, and immunotherapy in bladder cancer. A new epithelial cell subpopulation predicts response to surgery, chemotherapy, and immunotherapy in bladder cancer

The advent of neoadjuvant chemotherapy (NAC) prior to surgery and immune checkpoint therapy (ICT) have revolutionized bladder cancer management1-7. However, stratification of patients that would benefit most from these modalities remains a major clinical challenge. Here, we combine single nuclei RNA sequencing with spatial transcriptomics and single cell resolution spatial proteomic analysis of human bladder cancer to identify a novel epithelial subpopulation with therapeutic response prediction ability. These cells were defined by expression of Cadherin 12 (CDH12, N-Cadherin 2), catenins and other epithelial markers. CDH12-enriched tumors define patients with poor outcome following surgery with or without NAC. In contrast, CDH12-enriched tumors had a superior response to ICT. In all settings, patient stratification by tumor CDH12 enrichment offered better prediction of outcome than currently established bladder cancer subtypes. Molecularly, the CDH12 population resembles an undifferentiated state with inherent chemoresistance mediated through ALDH1A1 expression and fibroblast activation potential. Furthermore, CDH12-enriched cells express PD-L1 and PD-L2 and co-localize with exhausted T-cells, possibly mediated through CD49a (ITGA1), providing one explanation for ICT efficacy in these tumors. Altogether, this study describes a new cancer cell population with an intriguing diametric response to the major therapeutic modalities in bladder cancer. Importantly, it also provides a compelling rationale for the design of novel biomarker guided therapeutic clinical trials. Overall design: Visium spatial transcriptomics of human treatment-naïve muscle-invasive bladder cancer (n=4) fresh-frozen tissue.

新辅助化疗（neoadajuvant chemotherapy, NAC）与免疫检查点治疗（immune checkpoint therapy, ICT）的问世，彻底革新了膀胱癌的临床管理模式[1-7]。然而，筛选出可从这些治疗手段中获益最多的患者群体，仍是当前临床面临的重大挑战。本研究将单细胞核RNA测序（single nuclei RNA sequencing）、空间转录组学与单细胞分辨率空间蛋白质组学分析相结合，对人类膀胱癌样本展开研究，以期鉴定出一类具备治疗反应预测能力的新型上皮细胞亚群。这类细胞以钙粘蛋白12（Cadherin 12, CDH12，又称N-钙粘蛋白2）、连环蛋白及其他上皮标志物的表达为特征。CDH12高富集的肿瘤患者，无论是否联合新辅助化疗，术后预后均较差；与之相反，此类肿瘤患者对免疫检查点治疗的响应更为优异。在所有临床场景中，基于肿瘤CDH12富集程度进行患者分层，其预后预测效能均优于当前已确立的膀胱癌亚型分类方法。从分子层面来看，CDH12阳性细胞群呈现未分化状态，其固有化疗耐药性由ALDH1A1表达及成纤维细胞活化潜能介导。此外，CDH12高富集细胞还表达PD-L1与PD-L2，并与耗竭性T细胞共定位，这一现象可能由CD49a（ITGA1）介导，为这类肿瘤对免疫检查点治疗的有效性提供了一种合理解释。综上，本研究鉴定出一类全新的癌细胞群，该群体对膀胱癌主流治疗手段展现出引人关注的截然相反的响应特征。尤为重要的是，本研究还为设计以新型生物标志物为指导的治疗性临床试验提供了强有力的理论依据。整体研究设计：对4例未经治疗的肌肉浸润性膀胱癌（muscle-invasive bladder cancer）新鲜冰冻组织样本开展Visium空间转录组学分析。