Towards minimal residual disease-directed therapy in melanoma

Many patients with advanced cancers achieve dramatic responses to a panoply of therapeutics, yet retain minimal residual disease (MRD), which ultimately results in relapse. To gain insights into the biology of MRD we applied single-cell RNA-sequencing to malignant cells isolated from BRAF-mutant patient-derived xenograft (PDX) melanoma cohorts exposed to concurrent RAF/MEK-inhibition. We performed single cell RNA and single cell DNA sequencing from a PDX melanoma model before and on treatment (BRAF&MEK inhibitors). Furthermore, we performed bulk RNAseq of in vitro cultures that were derived from our PDX model, which were treated with BRAF and MEK inhibitors and FACS sorted for GFRA2high and low cells.许多晚期癌症患者虽可对多种治疗手段产生显著应答，但仍会残留微小残留病（minimal residual disease, MRD），最终引发肿瘤复发。为深入解析MRD的生物学特性，我们对接受联合RAF/MEK抑制治疗的BRAF突变型患者来源异种移植（patient-derived xenograft, PDX）黑色素瘤队列中分离的恶性细胞开展了单细胞RNA测序（single-cell RNA-sequencing）。我们还针对某一PDX黑色素瘤模型，在治疗前后（施加BRAF与MEK抑制剂）分别进行了单细胞RNA测序与单细胞DNA测序。此外，我们对源自该PDX模型的体外培养体系开展了批量RNA测序（bulk RNAseq）：该培养体系经BRAF和MEK抑制剂处理后，通过荧光激活细胞分选（fluorescence-activated cell sorting, FACS）分选出GFRA2高表达与低表达细胞群。