[The mechanism of circ_0023990/miR-873-5p/ANXA2 axis regulating radiosensitivity and development of thyroid carcinoma]

Dual effects of circRNA in thyroid and breast cancer

CircRNA, the latest research hotspot in the field of RNA, is a special non-coding RNA molecule, which is unable to encode proteins and bind polyribosomes. As a regulatory molecule, circRNA participates in cancer cell generation and progression mainly through the mechanism of competitive endogenous RNA. In numerous regulated cancer organs, the thyroid and breast are both endocrine organs, and both are regulated by the hypothalamic pituitary gland axis. Thyroid cancer (TC) and breast cancer (BC) are both sexually prevalent in women and both are affected by hormones, thus they are intrinsically linked. In addition, recent epidemiological surveys have found that, early metastasis and recurrence of breast cancer remain the main cause of survival in breast cancer patients. Although at home and abroad, studies have shown that new targeted anti-tumor drugs with numerous tumor markers are gradually being used in the clinic, evidence for potential molecular mechanisms affecting its prognosis lacks clinical studies. Therefore, we search the relevant literature, and based on the latest domestic and international consensus, review the molecular mechanisms and regulation relevance of circRNA, compare the difference of the same circRNA in two tumors, to more deeply understand and lay the foundation for future clinical diagnostic, therapeutic and prognostic studies in large samples.

Silencing circ_0000644 inhibits papillary thyroid cancer cell malignancy by combining with miR-671-5p to release the inhibition on ANXA2

BACKGROUND

Papillary thyroid cancer (PTC) is life-threatening due to its malignant progression. Considerable evidence demonstrates that circular RNA (circRNA) regulates PTC development. This study aims to explore the mechanism of circ_0000644 modulating PTC malignant progression.

METHODS

The RNA levels of circ_0000644, microRNA-671-5p (miR-671-5p) and annexin A2 (ANXA2) were detected by quantitative real-time polymerase chain reaction. Western blot was performed to check protein expression. Cell proliferation and cell apoptosis were investigated by 5-ethynyl-29-deoxyuridine and flow cytometry. Angiogenic capacity, migration and invasion were analyzed by tube formation assay and transwell assay. The interaction between miR-671-5p and circ_0000644 or ANXA2 was identified by dual-luciferase reporter assay. Xenograft mouse model assay was performed to analyze the effect of circ_0000644 on tumor formation in vivo.

RESULTS

Circ_0000644 and ANXA2 expression was significantly upregulated, while miR-671-5p was downregulated in PTC tissues and cells when compared with control groups. Circ_0000644 knockdown inhibited PTC cell proliferation, tube formation, migration, and invasion, but induced apoptosis in vitro. Moreover, circ_0000644 knockdown led to delayed tumorigenesis in vivo. In addition, circ_0000644 acted as a miR-671-5p sponge and mediated PTC cell tumor properties through miR-671-5p. ANXA2 was identified as a target gene of miR-671-5p, and its overexpression relieved miR-671-5p-induced effects in PTC cells. Furthermore, circ_0000644 depletion inhibited ANXA2 production by combining with miR-671-5p.

CONCLUSION

Circ_0000644 depletion repressed PTC cell tumor properties through the miR-671-5p/ANXA2 axis.