Circular RNAs act as regulators of autophagy in cancer

Abstract

Circular RNAs (circRNAs) are a large class of noncoding RNAs that are emerging as critical regulators of various cellular processes that are involved in the physiopathological mechanism of many human diseases, such as cardiovascular disease, atherosclerosis, diabetes mellitus, and carcinogenesis. Autophagy is a conserved and catabolic cellular process that degrades unfolded, misfolded, or damaged protein aggregates or organelles to maintain cellular homeostasis under physiological and pathological conditions. Increasing evidence has shown a link between circRNAs and autophagy that is closely related to the occurrence and development of human diseases, including cancer. In this review, we highlight recent advances in understanding the functions and mechanisms of circRNAs in the regulation of autophagy in cancer. These autophagy-related circRNAs contribute to cancer development and progression in various types of human cancer by activating or inhibiting autophagy. Cumulative research on the relationship between circRNAs and autophagy regulation provides critical insight into the essential role that circRNAs play in carcinogenesis and suggests new targets for tumor therapy.

Circular RNA-regulated autophagy is involved in cancer progression

“…Meanwhile, autophagy widely existed in almost all eukaryotes, playing essential roles in the material homeostasis in cancer cells ( Chang et al, 2021 ; Kitada and Koya, 2021 ). A growing number of articles demonstrate the associations between these two processes, which may break a novel research ground ( Zhou et al, 2021a ; Wang et al, 2021b ).…”

“…Previous evidence proved that both circRNAs and autophagy possess high conservation and whether the circRNA–autophagy network plays pro- or anti-neoplasm effects is dependent on cancer type, pathological grade, clinical stage, and even exogenous stimuli ( Kristensen et al, 2019 ; Zhou et al, 2021a ). Hence, we believe it is essential to illustrate the circRNA–autophagy regulative system in specific malignancies, which was overviewed in Figure 3 .…”

Use of Circular RNAs in Diagnosis, Prognosis and Therapeutics of Renal Cell Carcinoma

“…Autophagy is a catabolic conserved cellular process for homeostasis maintenance, through damaged protein aggregates or organelles degradation under physiological and pathological conditions. In fact, in many types of human cancers, circRNAs have been related to cancer development and progression by activation or inhibition of autophagy and/or apoptosis ( Du et al, 2017 ; Jin et al, 2018 ; Cui et al, 2021 ; Zhou et al, 2021 ) ( Table 1 ).…”

CircRNAs in Malignant Tumor Radiation: The New Frontier as Radiotherapy Biomarkers

“…During this process, some damaged proteins or organelles are encapsulated by autophagic vesicles with a double-layer membrane structure, and then transferred to lysosomes for degradation and recycling. Accruing reports show that circRNAs facilitate radiotherapy and chemotherapy tolerance by inducing autophagy ( 65 , 66 ). The crosstalk between circRNAs and radiation-mediated autophagy provides a new strategy for the regulation of tumors.…”