Newly discovered mechanisms that mediate tumorigenesis and tumour progression: circRNA-encoded proteins

Abstract

Proteins produced by cap-independent translation mediated by an internal ribosome entry site (IRES) in circular RNAs (circRNAs) play important roles in tumour progression. To date, numerous studies have been performed on circRNAs and the proteins they encode. In this review, we summarize the biogenesis of circRNAs and the mechanisms regulating circRNA-encoded proteins expression. We also describe relevant research methods and their applications to biological processes such as tumour cell proliferation, metastasis, epithelial-mesenchymal transition (EMT), apoptosis, autophagy and chemoresistance. This paper offers deeper insights into the roles that circRNA-encoded proteins play in tumours. It also provides a theoretical basis for the use of circRNA-encoded proteins as biomarkers of tumorigenesis and for the development of new targets for tumour therapy.

Keywords: circRNA; circRNA-encoded protein; research methods; translational medicine; tumour malignancy progression.

FIGURE 1

(A) Biogenesis of circRNAs. (B) IRES/MIRES driven translation. (C) Three types of translation.

FIGURE 2

(A–D) circEIF6‐224aa, circAXIN1‐295aa, circHER2‐103aa, circGGNBP2‐184aa promote tumour proliferation and metastasis. (E–H) circMAPK1‐109aa, circMAPK14‐175aa, circPLCE1‐411aa, circSEMA4B‐211aa inhibit tumour proliferation and metastasis.

FIGURE 3

(A) circDIDO1‐529aa promotes tumour apoptosis. (B) circGSPT1‐238aa inhibits tumour autophagy. (C) circFNDC3B‐218aa inhibits tumour EMT. (D) CORO1C‐47aa affects the tumour microenvironment by suppressing tumour angiogenesis.

FIGURE 4

(A, B) circMRPS35‐168aa and circMAP3K4‐455aa promote tumour chemoresistance by inhibiting apoptosis. (C) circASK1‐272aa inhibits tumour chemoresistance by promoting apoptosis. (D) circATG4B‐222aa promotes tumour chemoresistance by promoting autophagy.