Introduction

Sunitinib is indicated as first-line treatment of metastatic renal cell carcinoma (mRCC) and suppress angiogenesis and tumor cell proliferation through binding to vascular endothelial growth factor receptor and platelet-derived growth factor receptor. However, the clinical benefit in progression free survival is limited and almost patients have a relapse of disease due to acquired resistance. MicroRNA, which are non-protein-coding small RNAs, are involved in cancer progression and regulate gene expression at the post-transcriptional level by binding to the untranslated region (3`UTR) of target mRNAs. The purposes of this study were to generate sunitinib resistant RCC cell lines and to detect candidate miRNAs for regulating sunitinib resistance.

Methods

The renal cell carcinoma cell line ACHN and RCC23 were cultured in RPMI1640 with 10% Fetal Bovine Serum and 1% of Penicillin-Streptomycin. Sunitinib resistant cells were generated by continuous exposure for three months and gradually increasing doses of sunitinib up to IC50% (inhibitory concentration) of each cell. We used these cells as sunitinib resistant ACHN and RCC23 cell lines (SR-ACHN, SR-RCC23) for the subsequent verification. For microarray analysis, total RNA was labeled using a 3D-Gene miRNA labeling kit. Reverse transcription was performed with a stem-loop RT Megaplex Primer Pool and the Taqman MicroRNA Reverse Transcription Kit.

Results

According to previous MTT assay, the IC50% of ACHN cell was 10µM and that of RCC23 cell was 14µM. SR-ACHN and SR-RCC23 cells exhibited significantly higher resistance to sunitinib treatment compared with that of these sunitinib sensitive cells. Microarray analysis was performed comparing ACHN vs SR-ACHN and RCC23 vs SR-RCC23, respectively, to evaluate the miRNA profiles of each cells. In SR-ACHN and SR-RCC23 cells as compared with ACHN and RCC23 cells, the CT values of miR-575, -642b-3p and -4430 have significantly increased, while the CT values of miR-18a-5p, -29b-1-5p, -431-3p and -4521 have significantly decreased with real-time RT-PCR.

Conclusions

We created sunitinib resistant cell lines SR-ACHN and SR-RCC23 and identified microRNAs considering related with sunitnib resistant by performing microarray. By regulating these microRNAs may contribute to the improvement of sunitinib resistance.

Funding

none