Potentiation of Carboplatin-Mediated DNA Damage by the Mdm2 Modulator Nutlin-3a in a Humanized Orthotopic Breast-to-Lung Metastatic Model.
Triple-negative breast cancers (TNBC) are typically resistant to treatment, and strategies that build upon frontline therapy are needed. Targeting the murine double minute 2 (Mdm2) protein is an attractive approach, as Mdm2 levels are elevated in many therapy-refractive breast cancers. The Mdm2 protein-protein interaction inhibitor Nutlin-3a blocks the binding of Mdm2 to key signaling molecules such as p53 and p73α and can result in activation of cell death signaling pathways. In the present study, the therapeutic potential of carboplatin and Nutlin-3a to treat TNBC was investigated, as carboplatin is under evaluation in clinical trials for TNBC. In mutant p53 TMD231 TNBC cells, carboplatin and Nutlin-3a led to increased Mdm2 and was strongly synergistic in promoting cell death in vitro. Furthermore, sensitivity of TNBC cells to combination treatment was dependent on p73α. Following combination treatment, γH2AX increased and Mdm2 localized to a larger degree to chromatin compared with single-agent treatment, consistent with previous observations that Mdm2 binds to the Mre11/Rad50/Nbs1 complex associated with DNA and inhibits the DNA damage response. In vivo efficacy studies were conducted in the TMD231 orthotopic mammary fat pad model in NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ (NSG) mice. Using an intermittent dosing schedule of combined carboplatin and Nutlin-3a, there was a significant reduction in primary tumor growth and lung metastases compared with vehicle and single-agent treatments. In addition, there was minimal toxicity to the bone marrow and normal tissues. These studies demonstrate that Mdm2 holds promise as a therapeutic target in combination with conventional therapy and may lead to new clinical therapies for TNBC.
Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana.
Eva
E
Tonsing-Carter
In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana. Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Barbara J
BJ
Bailey
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana. Goodman Campbell Brain and Spine, Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana.
M Reza
MR
Saadatzadeh
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana. Goodman Campbell Brain and Spine, Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana.
Jixin
J
Ding
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Haiyan
H
Wang
In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana.
Anthony L
AL
Sinn
In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana.
Kacie M
KM
Peterman
In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana.
Tiaishia K
TK
Spragins
In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana.
Jayne M
JM
Silver
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Alyssa A
AA
Sprouse
Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
Taxiarchis M
TM
Georgiadis
Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
T Zachary
TZ
Gunter
Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
Eric C
EC
Long
Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
Robert E
RE
Minto
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Christophe C
CC
Marchal
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Christopher N
CN
Batuello
Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana.
Ahmad R
AR
Safa
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana. Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana. Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, Düsseldorf, Germany.
Helmut
H
Hanenberg
Indiana Institute for Biomedical Sciences Imaging, Department of Radiology, Indiana University School of Medicine, Indianapolis, Indiana.
Paul R
PR
Territo
Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana.
George E
GE
Sandusky
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana. Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana.
Lindsey D
LD
Mayo
Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee.
Christine M
CM
Eischen
Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana.
Harlan E
HE
Shannon
Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana. In Vivo Therapeutics Core, Indiana University Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana. Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana. kpollok@iu.edu.
Karen E
KE
Pollok
D000818:Animals; D016190:Carboplatin / Q000008:administration & dosage; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002986:Clinical Trials as Topic; D004249:DNA Damage / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000235:genetics; D004195:Disease Models, Animal; D006657:Histones / Q000096:biosynthesis; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage*; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology / Q000556:secondary; D061986:MCF-7 Cells; D051379:Mice; D009362:Neoplasm Metastasis; D009687:Nuclear Proteins / Q000235:genetics; D010879:Piperazines / Q000008:administration & dosage*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics*; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics
D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D007093:Imidazoles; D009687:Nuclear Proteins; D010879:Piperazines; C495901:TP53 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C482205:nutlin 3; D016190:Carboplatin; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2