Identification of circular RNAs during colorectal cancer progression and metastasis using a preclinical mouse model during LDM topotecan chemotherapy

To find candidate circRNAs and to unravel their molecular functions during colorectal cancer progression and during LDM topotecan chemotherapy, we utilized a xenograft mouse model based on the HT29.hCG.Luc colorectal cancer cell line (referred to as HT29) implanted into SCID mice. HT29 cells were injected into the spleen and primary tumors developed. Three mice served as control group while two mice served as LDM topotecan treated group. After another 4-6 weeks, liver metastasis can be detected and resected for further investigation. For a global view on gene expression changes, we performed rRNA-depletion RNA-Seq from HT29 cells, primary tumors and liver metastases. 100 ng of total RNA from HT29 cells, primary tumors (PT) and liver metastases (LM) was used for preparation of rRNA-depleted RNA library using Ovation Human FFPE RNA-Seq Libray System according to manufacturer’s protocol. 3 mice were used for collecting RNA from C-PT and C-LM; 2 LDM topotecan treated mice were used for collecting RNA from T-LM; and 3 replicates were used for collecting RNA from HT29 cells.