Single-cell analysis reveals inter- and intra-tumor heterogeneity in metastatic breast cancer

The plasticity and heterogeneity of cancer cells are known to play a major role in malignant progression, yet the precise molecular drivers of metastases remain elusive. We performed single-cell RNA-Seq (scRNA-Seq) on tumours and matched lung macrometastases of patient-derived xenografts (PDXs) of breast cancer to identify molecular mechanisms of metastasis during colonization. Overall design: Tumors and matched lung metastases from PDX models grown in NSG mice were dissociated and human cells purified by FACS . PDX models cells selection relied on the CD298 human-specific marker. Samples derived from a cell line MDA-MB-231 expressing a GFP-Luciferase construct were selected based on GFP expression. Single cell isolation was performed on the Fluidigm C1 platform. mRNA was isolated with the Takara SMART-Seq Ultra Low RNA kit. Libraries for Illumina sequencing were prepared with the Nextera XT DNA Library Preparation Kit.