Journal: bioRxiv
Article Title: Apurinic/apyrimidinic nuclease 1 drives genomic evolution contributing to chemoresistance and tumorigenesis in solid tumor
doi: 10.1101/2022.04.20.488830
Figure Lengend Snippet: (A) Chemical or transgenic suppression of APE1 reduces cisplatin-induced DNA breaks in solid cancer cells. (I) Cancer cell lines (FLO-1, esophageal adenocarcinoma; A549, epithelial lung carcinoma; MCF7, breast cancer) were treated with APE1 inhibitor (API3; 1.5 ⍰M), cisplatin (5 ⍰M) or combination of both and live cell fractions evaluated for expression of APE1 and γ -H2AX (marker of DNA breaks) by Western blotting. Lanes: 1, control; 2, API3; 3, cisplatin; 4, API3+cisplatin. (II) Control and APE1-knockdown cancer cells (OE19, esophageal adenocarcinoma; A549, epithelial lung carcinoma) were treated with cisplatin (15 ⍰M) and expression of APE1 and γ -H2AX assessed by Western blotting. Lanes: 1, control shRNA; 2, control shRNA treated with cisplatin; 3, APE1-shRNA; 4, APE1-shRNA treated with cisplatin; (B-C) Chemical or transgenic inhibition of APE1 inhibits RAD51 expression and HR activity. (B) EAC ( FLO-1) cells treated with API3 were evaluated for RAD51 expression by Western blotting (I), RAD51 promoter activity using a plasmid in which RAD51 drives luciferase expression (II), and HR activity using the plasmidbased assay (III). (C) EAC (FLO-1) cells were treated with shRNAs (CS, control shRNAs; KD, cells treated with APE1-targeting shRNAs). Panels: (I) APE1 expression evaluated by Western blotting; (II) HR activity assessed by plasmid-based assay; (III) Expression of RAD51 (top panel) and its phosphorylated form (bottom panel) evaluated by Western blotting; (D) Dose-dependent inhibition of HR activity by APE1 inhibitor in solid tumor cell lines. Cancer cell lines (OE19, esophageal adenocarcinoma; MCF7, breast cancer; A549, epithelial lung carcinoma; PC3, prostate adenocarcinoma) were treated with APE1 inhibitor (API3) at different concentrations for 48 HR and impact of HR activity determined using plasmid-based functional assay described in Methods.
Article Snippet: Affinity purified human APE1 antibody (NB100-101), Novus Biologicals LLC, Centennial, CO; FEN1 Antibody (2746s), Cell Signaling Technology, Inc., Danvers, MA; EXO1 antibody (A302-639A), Bethyl Laboratories, Montgomery, TX, USA; EME1 antibody (PA5-101988), Invitrogen, Carlsbad, CA, USA; RAD51 antibody (ab176458), Abcam, Cambridge, MA, USA; RPA32(A300-244A), Bethyl Laboratories, Montgomery, TX, USA; RPA32 (phospho Ser4 and phospho Ser8) antibody, Novus Biologicals LLC, Centennial, CO; Anti-phospho-H2A.X (Ser139) antibody, (07-164), Sigma-Aldrich, St. Louis, MO, USA; GAPDH (14C10) rabbit monoclonal antibody ( #2118), Cell Signaling Technology, Inc., Danvers, MA; ß-Tubulin antibody (#2146), Cell Signaling Technology, Inc., Danvers, MA.
Techniques: Transgenic Assay, Expressing, Marker, Western Blot, Control, Knockdown, shRNA, Inhibition, Activity Assay, Plasmid Preparation, Luciferase, Functional Assay