Circ_0,007,331 Promotes the PTX Resistance and Progression of Breast Cancer via miR-200b-3p/ANLN.

INTRODUCTION: The objective of our study was to explore the expression pattern of circular ribonucleic acid (RNA)_0,007,331 (circ_0,007,331) in breast cancer (BC) and its functional association with cellular paclitaxel (PTX) resistance and proliferation, migration, invasion and apoptosis.

METHODS: Real-time quantitative polymerase chain reaction was applied to measure RNA expression. The PTX resistance of BC cells was analyzed by cell counting kit-8 assay. Flow cytometry was applied to assess cell cycle progression and cell apoptosis. Transwell assays were utilized to analyze cell migration and invasion abilities. Protein expression was determined by Western blot assay. The target relationship between microRNA-200b-3p (miR-200b-3p) and circ_0,007,331 or Anillin (ANLN) was verified by dual-luciferase reporter assay and RNA-pull down assay. The in vivo role of circ_0,007,331 was analyzed using xenograft tumor model.

RESULTS: Circ_0,007,331 expression was elevated in PTX-resistant BC cell lines relative to parental BC cell lines. Circ_0,007,331 contributed to the PTX resistance, proliferation, migration, invasion and suppressed the apoptosis of BC cells. Circ_0,007,331 interacted with miR-200b-3p in BC cells. Circ_0,007,331 silencing-mediated effects in BC cells were largely overturned by the knockdown of miR-200b-3p. ANLN was a target of miR-200b-3p in BC cells. Circ_0,007,331 silencing reduced ANLN expression partly through upregulating miR-200b-3p in BC cells. miR-200b-3p overexpression-induced effects in BC cells were largely counteracted by the accumulation of ANLN. Circ_0,007,331 silencing aggravated PTX-mediated inhibitory effect on tumor growth in vivo.

CONCLUSIONS: Circ_0,007,331 contributed to the PTX resistance, proliferation and motility and inhibited the apoptosis of BC cells through mediating miR-200b-3p/ANLN signaling.