GSM6533606: mouse breast cancer scATAC-seq; Mus musculus; ATAC-seq
Tumor tissue specimens from mouse or human specimens was minced on ice. The tissue was then digested for 3x 30 minutes in a 37C water bath agitator in 0.5 mg/mL collagenase (collagenase type IV, ThermoFisher) digest buffer in Medium 199 (HyClone, GE Healthcare) consisting of 5% fetal bovine serum (Gibco FBS, ThermoFisher), DNase I (Worthington), Poloxamer 188 (Cat. P5556-100ML, Sigma), HEPES, and CaCl2. The digest was quenched with quench media (DMEM (Gibco DMEM, ThermoFisher) with 15% FBS), then centrifuged at 300 x G for 5 minutes at 4C, resuspended in quench media, and filtered through 100, 70, and 40m cell strainers (Falcon cell strainer, ThermoFisher). Red blood cell lysis was performed using Hybri-Max (Sigma) per the manufacturer's protocol. Cells were counted and re-suspended for further processing. Single-cell ATAC sequencing (scATAC-seq) was then performed at the Stanford Genomics Facility (SGF) using the 10x Genomics platform. The relevant protocols were followed per manufacturer's guidelines. Nuclei isolation was pursued as for scATAC-seq and multiome sequencing using 0.1x lysis buffer with 3-minute incubation. Final libraries were analyzed on an Agilent Bioanalyzer High Sensitivity DNA chip for qualitative control purposes. Libraries were sequenced on a HiSeq 4000 Illumina platform targeting 50,000 reads per cell.