High throughput sequencing of small cell lung cancer chemosensitive H69 and corresponding chemoresistant H69AR

Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer. Although most patients are initially sensitive to first-line chemotherapy with combined cisplatin and etoposide, chemotherapy drugs resistance easily develops and quickly leads to tumor progression. Therefore, understanding mechanisms of chemotherapy drugs resistance and how to reverse it is key to improving the prognosis of patients with SCLC. The parental SCLC cell lines H69 and corresponding doxorubicin-induced multidrug resistant variant (H69AR) were used to explore the mechanism of chemoresistance in SCLC. RNA was extracted from SCLC cells (H69 and H69AR). The RNA quality was assessed with a Bioanalyzer 2100 DNA Chip 7500 (Agilent Technologies), and samples with an RNA integrity number (RIN) of over 7 were further analyzed by RNA-seq. All sequencing reactions were performed on an Illumina HiSeq 2000 instrument (Illumina, San Diego, CA, USA). We used HISAT2 (version 2.1.0) with the default setting to map the RNA-seq data to the human reference genome (NCBI38/hg38).We aggregated the read counts at the gene level using HTSeq.