CircPTK2 (hsa_circ_0005273) as a novel therapeutic target for metastatic colorectal cancer

Abstract

Background: As a novel class of noncoding RNAs, circRNAs have been recently identified to regulate tumorigenesis and aggressiveness. However, the function of circRNAs in colorectal cancer (CRC) metastasis remains unclear. We aimed to identify circRNAs that are upregulated in CRC tissues from patients and study their function in CRC metastasis. Methods: We compared six pairs of CRC tissues and their matched adjacent non-tumor tissues by using circRNA microarray. We first evaluated the expression of circPTK2 (hsa_circ_0005273) in fresh tissues from CRC tumors and corresponding adjacent tissues by qPCR analysis. CircPTK2 expression levels in the tissue microarray with 5 years of survival information were determined by RNA-ISH analysis. Meanwhile, the expression levels of circulating circPTK2 were further analyzed according to the patients' clinical features. We analyzed cell apoptosis, colony formation, migration, and invasion in CRC cells. To further elucidate the effect of circPTK2 in CRC metastasis, we also conducted a colon cancer hepatic and pulmonary metastasis experiment. We used RNA biotin-labeled pull down and mass spectrometry to identify the target of circPTK2. We established a PDTX model to evaluate the effect of shRNA specifically targeting circPTK2 on tumor metastasis. Results: We identified a novel circRNA, circPTK2, which is back-spliced of three exons (exons 27, 28 and 29) of PTK2 by using circRNA microarray, bioinformatics and functional studies. CircPTK2 was elevated in CRC tissues and positively associated with tumor growth and metastasis. CRC patients with increased circPTK2 expression were positively correlated with poorer survival rates. Furthermore, our studies showed that circPTK2 could promote EMT of CRC cells in vitro and in vivo by binding to vimentin protein on sites Ser38, Ser55 and Ser82. We further demonstrated the interaction of circPTK2 and vimentin mediated the regulation of CRC by knockdown or overexpression of vimentin. In addition, we revealed that tail vein injection of shRNA specifically targeting circPTK2 blunt tumor metastasis in a patient-derived CRC xenograft model. Conclusions: Collectively, these results demonstrate that circPTK2 exerts critical roles in CRC growth and metastasis and may serve as a potential therapeutic target for CRC metastasis, and also a promising biomarker for early diagnosis of metastasis.

Construction of circRNA-based ceRNA Network to Reveal the Role of circRNAs in the Progression and Prognosis of Hepatocellular Carcinoma

“…The result showed that circRNA played signi cant role in occurrence and development of refractory breast cancer. Yang et al veri ed the RNA expression level of circPTK2 in colon cancer and normal colon tissues, and veri ed that the expression content of circPTK2 is related to the clinical stage of colon cancer patients, and in vitro and PDTX models, veri ed that the increase in circPTK2 expression can be Promote the metastasis of colon cancer [19]. The results of Chen et al con rmed that circSnx5 could act as a miR-544 sponge to reduce Suppressors of cytokine signaling 1 (SOCS1) target inhibition and inhibit the nuclear transport of PU.1, and regulate dendritic cell (DC) activation and function [20].…”

Hypoxia‐induced hsa_circ_0000826 is linked to liver metastasis of colorectal cancer

“…Briefly, samples were incubated with Hsa_circ_0000826 probes at 40°C for 2 hours. After hybridization, a series of single amplification procedures were performed and finally visualized with Fast Red 11 . The number of puncta was calculated in 200 cells/group.…”

CircRNAs: biogenesis, functions, and role in drug-resistant Tumours

“…In addition, the expression levels hsa_circ_0124055 and hsa_circ_0101622 in tumour tissues and plasma of patients with thyroid cancer are significantly increased, and the overall survival times of patients with a high expression level of either circRNA were shorter than those of patients with a low expression level of either circRNA. These results suggest that both of these circRNAs are helpful biomarkers for the prognosis and diagnosis of thyroid carcinoma and can be used as clinical therapeutic targets [112]. In addition, regarding drug resistance, hsa_circ_0006528 [113], circMTO1 [114], circ_0001546 [115], and circ-LARP4 [116] exhibit abnormal expression levels in drug-resistant cells, suggesting that they could be used as diagnostic markers for drug resistance in tumours.…”