title: Targeting NF-κB RelA/p65 phosphorylation overcomes RITA resistance.
abstract: Inactivation of p53 occurs frequently in various cancers. RITA is a promising anticancer small molecule that dissociates p53-MDM2 interaction, reactivates p53 and induces exclusive apoptosis in cancer cells, but acquired RITA resistance remains a major drawback. This study found that the site-differential phosphorylation of nuclear factor-κB (NF-κB) RelA/p65 creates a barcode for RITA chemosensitivity in cancer cells. In naïve MCF7 and HCT116 cells where RITA triggered vast apoptosis, phosphorylation of RelA/p65 increased at Ser536, but decreased at Ser276 and Ser468; oppositely, in RITA-resistant cells, RelA/p65 phosphorylation decreased at Ser536, but increased at Ser276 and Ser468. A phosphomimetic mutation at Ser536 (p65/S536D) or silencing of endogenous RelA/p65 resensitized the RITA-resistant cells to RITA while the phosphomimetic mutant at Ser276 (p65/S276D) led to RITA resistance of naïve cells. In mouse xenografts, intratumoral delivery of the phosphomimetic p65/S536D mutant increased the antitumor activity of RITA. Furthermore, in the RITA-resistant cells ATP-binding cassette transporter ABCC6 was upregulated, and silencing of ABCC6 expression in these cells restored RITA sensitivity. In the naïve cells, ABCC6 delivery led to RITA resistance and blockage of p65/S536D mutant-induced RITA sensitivity. Taken together, these data suggest that the site-differential phosphorylation of RelA/p65 modulates RITA sensitivity in cancer cells, which may provide an avenue to manipulate RITA resistance.
authors.affiliation: Department of Medical Microbiology, Immunology & Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Bu
authors.affiliation: Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA.
authors.forename: Guoshuai
authors.initials: G
authors.lastname: Cai
authors.affiliation: Department of Medical Microbiology, Immunology & Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Medical Microbiology, Immunology & Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA.
authors.forename: Chenfei
authors.initials: C
authors.lastname: Huang
authors.affiliation: Cancer Research Institute, University of South China, Hengyang, Hunan 421001, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Medical Microbiology, Immunology & Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (Incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Cai
authors.affiliation: Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (Incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (Incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Huang
authors.affiliation: Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (Incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China. Electronic address: dfliao66@aliyun.com.
authors.forename: Duan-Fang
authors.initials: DF
authors.lastname: Liao
authors.affiliation: Department of Medical Microbiology, Immunology & Cell Biology, Simmons Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62794, USA; Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (Incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China. Electronic address: dcao@siumed.edu.
authors.forename: Deliang
authors.initials: D
authors.lastname: Cao
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005260:Female; D005663:Furans / Q000494:pharmacology*; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D061986:MCF-7 Cells; D008819:Mice, Nude; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D034622:RNA Interference; D012694:Serine; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D005663:Furans; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012694:Serine; D051996:Transcription Factor RelA; C102029:ABCC6 protein, human; C118989:NSC 652287; C498143:RELA protein, human
keywords: ABCC6; Chemoresistance; NF-κB RelA/p65; RITA