New insights into molecular mechanisms underlying malignant transformation of endometriosis: BANCR promotes miR-612/CPNE3 pathway activity

RESEARCH QUESTION: Does LncRNA BANCR promote the malignant transformation of endometriosis by activating the miR-612/CPNE3 pathway? DESIGN: The expression patterns of BANCR, miR-612 and CPNE3 in normal endometrium, eutopic endometrium from endometriosis, eutopic endometrium or malignant tissues from endometriosis-associated ovarian cancer. On the basis of primary normal endometrial stromal cells (NESC) and eutopic endometrial stromal cells (EESC), the regulatory relationships between BANCR, miR-612 and CPNE3, and the potential mechanisms that promote the malignant transformation of endometriosis, were elucidated in vitro and in vivo. RESULTS: The expression levels of BANCR and CPNE3 were lowest in normal endometrium, significantly increased in eutopic endometrium (P < 0.05) and was significantly increased in eutopic endometrium (P < 0.05). During the malignant transformation of endometriosis, the expression levels of BANCR and CPNE3 were significantly upregulated (P < 0.05), whereas those of miR-612 were significantly downregulated (P < 0.05). miRNA-612 was found to target BANCR and CPNE3. The overexpression and knockdown of BANCR in NESC and EESC upregulated and downregulated the expression of CPNE3 and promoted or prevented cell proliferation and migration, respectively; these effects were reversed by miR-612 mimics and inhibitor. These changes were all statistically significant (P < 0.05). In-vivo experiments revealed that BANCR significantly increased the survival of subcutaneous endometrial cells by regulating miR-612/CPNE3 (P < 0.05). CONCLUSION: The expression of BANCR gradually increased with the progression of endometriosis during malignant transformation, and promoted the proliferation and migration of endometrial cells via the miR-612/CPNE3 pathway. BANCR may represent a novel target for monitoring the malignant transformation of endometriosis.