Circular RNA F-circSR derived from SLC34A2-ROS1 fusion gene promotes cell migration in non-small cell lung cancer

Ke Wu,Yong Peng,Wenchen Pu,Yu-Quan Wei,Xun Liao,Canhua Huang,Youling Gong,Jian-Kang Zhou,Shuangyan Tan,Juan He

doi:10.1186/s12943-019-1028-9

Abstract

Cancer-associated chromosomal translocations are reported to generate oncogenic circular RNA (circRNA), contributing to tumorigenesis. The fusion gene SLC34A2-ROS1 (solute carrier family 34 member 2 and ROS proto-oncogene 1) plays an important role in non-small cell lung cancer (NSCLC) progression. However, whether SLC34A2-ROS1 gene can produce circRNA remains unknown. Here, we identified two novel circRNAs (F-circSR1 and F-circSR2) generated from SLC34A2-ROS1 fusion gene, while F-circSR1 has higher expression than F-circSR2. Functional studies through gain- and loss-of-function strategies showed that both F-circSRs promote cell migration in lung cancer cells, whereas they have little effect on cell proliferation. Using the minigene GFP reporter assay, we verified that the flanking complementary sequences with canonical splicing sites are essential for F-circSR biogenesis. Therefore, our findings demonstrate the oncogenic role of F-circSR in NSCLC and highlight its therapeutic potential.

Highlights

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer worldwide, accounting for approximately 85% of lung cancers [1]
Identification of F-circSR in NSCLC cells It is reported that the NSCLC cell line HCC78 harbors two forms of solute carrier family 34 member 2 (SLC34A2)-ROS proto-oncogene 1 (ROS1) fusion genes expressing long and short transcripts
(See figure on previous page.) Fig. 2 F-circSR promotes cell migration in NSCLC cells. a Schematic representation of pCRE5-F-circSR-expressing plasmid. b Agarose gel electrophoresis and Sanger sequencing of reverse transcription polymerase chain reaction (RT-PCR) products from HEK293T cells transfected with F-circSR-expressing plasmid or empty vector. c Agarose gel electrophoresis of RT-PCR products from A549 and H1299 cells stably expressing F-circSR. d Representative images of Transwell migration assays and quantification in A549 and H1299 cells with or without F-circSR overexpression. e~f Representative images of wound healing assays in H1299 and A549 cells with or without F-circSR overexpression. g~h F-circSR knockdown attenuates the migratory ability in F-circSR1 (g) or F-circSR2 (h) overexpressing H1299 cells

Summary

Introduction

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer worldwide, accounting for approximately 85% of lung cancers [1]. We identify the novel circRNA F-circSRs generated from SLC34A2-ROS1 gene. F-circSRs, independent from SLC34A2-ROS1 fusion protein, have little effect on cell proliferation, but promote cell migration in lung cancer cells, highlighting the oncogenic role of F-circSRs in NSCLC.

Results

Conclusion