Figure 2.

Knockdown of PARP9 inhibits the malignant phenotypes and chemoresistance of FUL-resistant breast cancer cells. Sh-PARP9 or sh-NC was transfected into MCF-7/FUL cells, A – qRT-PCR and western blot to measure PARP9 expression; B – drug resistance assessment of cells after FUL treatment; C – Western blot to examine the expression of drug resistance-related proteins MRP1 and MDR1; D – plate clone formation assay to monitor cell proliferation; E – scratch test to observe cell migration; F – transwell assay to assess cell invasion; G – flow cytometry to detect cycle distribution of cells; H – flow cytometry to test cell apoptosis; I – Western blot to measure cyclin D1, p-Cdc2, and cleaved caspase 3 expression. Data were displayed in the form of mean ± standard deviation and experiments were repeated 3 times

*p < 0.05 compared with the sh-NC group.

PARP – poly-ADP-ribose polymerase, CT – chemotherapy, DR – drug-resistant, FUL – fulvestrant, sh – short hairpin, qRT-PCR – quantitative reverse transcription-polymerase chain reaction, MRP – multidrug resistance protein, MDR – multiple drug resistance, Cdc – cell division cycle, NC – negative control.