Fig 2: Enforced expression of miR-1286 enhanced drug sensitivity of PTX-resistant BC cells in vitro by down-regulating HK2. HK2 protein level by Western blot in MDA-MB-231/PTX and MCF-7/PTX cells transfected with pcDNA or HK2 overexpressing plasmid (HK2) (A), miR-NC mimic, miR-1286 mimic, miR-1286 mimic+pcDNA or miR-1286 mimic+HK2 overexpressing plasmid (B and C). (D and E) MDA-MB-231/PTX and MCF-7/PTX cells were transfected with miR-NC mimic, miR-1286 mimic, miR-1286 mimic+pcDNA or miR-1286 mimic+HK2 overexpressing plasmid and then exposed to various doses of PTX, followed by the detection of cell viability by CCK-8 assay. MDA-MB-231/PTX and MCF-7/PTX cells were transfected with miR-NC mimic, miR-1286 mimic, miR-1286 mimic+pcDNA or miR-1286 mimic+HK2 overexpressing plasmid before PTX exposure, followed by the measurement of cell colony formation by colony formation assay (F and G), cell cycle distribution by flow cytometry (H and I), cell apoptosis by flow cytometry (J). **P < 0.01 or ***P < 0.001 by a Student’s t-test or ANOVA with Tukey’s post hoc test.

Fig 3: CircHIPK3 silencing hampered tumor growth and promoted PTX sensitivity in vivo. (A) Representative images of the xenograft tumors at day 21 derived from sh-NC-infected or sh-circHIPK3-transduced MCF-7/PTX cells with NS (PBS) or PTX (3 mg/kg) administration. (B) Growth curves of the xenograft tumors formed by subcutaneous injection into the nude mice of sh-NC-infected or sh-circHIPK3-transduced MCF-7/PTX cells with NS (PBS) or PTX administration (n = 6 per group). (C) Tumor weight at day 21 of the xenograft tumors (n = 6 per group). Relative circHIPK3 (D), miR-1286 (E), HK2 mRNA (F) expression levels by qRT-PCR, HK2 protein level by Western blot (G) and immunohistochemistry (H) in the subcutaneous xenograft tumors (day 21, n = 6 per group). *P < 0.05, **P < 0.01 or ***P < 0.001 by ANOVA with Tukey’s post hoc test.