lncRNA TTN‐AS1 facilitates proliferation, invasion, and epithelial‐mesenchymal transition of breast cancer cells by regulating miR‐139‐5p/ZEB1 axis

Abstract

Breast cancer is a common malignant tumor suffered predominantly by women worldwide, which results in serious levels of morbidity and mortality. To control the effects of the cancer, it is critically important to elucidate the pathophysiological processes by which it occurs and develops. Reports have demonstrated that long noncoding RNAs perform a critical role in the development and metastasis of cancers. The lncRNA TTN-AS1 is considered carcinogenic. Nevertheless, the importance and biological functions of TTN-AS1 in breast cancer require greater exploration. In the current paper, we observed that TTN-AS1 expression was significantly upregulated in breast cancer tissues/cells compared with those that are healthy. TTN-AS1 enhanced the proliferation, migration, invasion, and epithelialmesenchymal transformation of breast cancer cells. Furthermore, a direct target of TTN-AS1, miR-139-5p was negatively regulated. In addition, zinc finger E-box binding homeobox 1 (ZEB1) is an important nuclear transcription factor, the expression of which is increased in multiple tumors. Here, we also found that ZEB1 is a target of miR-139-5p, of which TTN-AS1 could regulate the expression through competition with miR-139-5p. That is, TTN-AS1 promoted proliferation and invasion of breast cancer cells by interaction with the miR-139-5p/ZEB1 axis. In conclusion, the present study aimed to illustrate the significance of TTN-AS1 in breast cancer metastasis and contribute to potentially innovative strategies for its treatment.

Circ_0072995 promotes cell carcinogenesis via up-regulating miR-149-5p-mediated SHMT2 in breast cancer

“…On a global scale, breast cancer is the most frequently diagnosed female malignancy, which seriously threatens the health of women in the word [1]. As the first leading cause among female malignancy, the overall occurrence and mortality of patients with breast cancer have not significantly reduced despite the great improvement in diagnosis and therapeutic technology [2,3]. Hence, it is paramount to investigate the mechanism underlying the progression of breast cancer for managing the clinical treatments.…”

CircRNA DNA methyltransferase 1 silence inhibits breast cancer development by regulating micoRNA‐485‐3p/zinc finger E‐box binding homeobox 1 axis

“…ZEB1 acts as an epithelial‐mesenchymal transition‐related factor, which plays an oncogenic role in breast cancer by regulating multiple processes 26 . Liang et al and Fang et al suggested ZEB1 promoted breast cancer cell proliferation and invasion 16,27 . Moreover, Jin et al suggested that ZEB1 could facilitate breast cancer cell migration and invasion and restrain apoptosis 17 .…”

Circ_0000518 contributes to breast cancer development depending on the regulation of miR-1258/ZEB1 axis

“…For instance, Jiang et al claimed that miR-203 enhanced the radio-sensitivity in gastric cancer cells via suppressing ZEB1 (Jiang et al 2019). Fang et al claimed that TTN-AS1 aggravated BC progression through up-regulating ZEB1 via sponging miR-139-5p (Fang et al 2020). Liang et al found that miR-1236-3p hampered BC development through inhibiting ZEB1 (Liang et al 2019).…”