title: Nutlin-3a efficacy in sarcoma predicted by transcriptomic and epigenetic profiling.
abstract: Nutlin-3a is a small-molecule antagonist of p53/MDM2 that is being explored as a treatment for sarcoma. In this study, we examined the molecular mechanisms underlying the sensitivity of sarcomas to Nutlin-3a. In an ex vivo tissue explant system, we found that TP53 pathway alterations (TP53 status, MDM2/MDM4 genomic amplification/mRNA overexpression, MDM2 SNP309, and TP53 SNP72) did not confer apoptotic or cytostatic responses in sarcoma tissue biopsies (n = 24). Unexpectedly, MDM2 status did not predict Nutlin-3a sensitivity. RNA sequencing revealed that the global transcriptomic profiles of these sarcomas provided a more robust prediction of apoptotic responses to Nutlin-3a. Expression profiling revealed a subset of TP53 target genes that were transactivated specifically in sarcomas that were highly sensitive to Nutlin-3a. Of these target genes, the GADD45A promoter region was shown to be hypermethylated in 82% of wild-type TP53 sarcomas that did not respond to Nutlin-3a, thereby providing mechanistic insight into the innate ability of sarcomas to resist apoptotic death following Nutlin-3a treatment. Collectively, our findings argue that the existing benchmark biomarker for MDM2 antagonist efficacy (MDM2 amplification) should not be used to predict outcome but rather global gene expression profiles and epigenetic status of sarcomas dictate their sensitivity to p53/MDM2 antagonists.
authors: Authors' Affiliations: Sarcoma Research Group, Discipline of Medicine, Centre for Personalised Cancer Medicine, Faculty of Health Sciences, School of Molecular and Biomedical Science, Departments of Orthopaedics and Trauma and Haematology, Cancer Clinical Trials Unit, Royal Adelaide Hospital; Department of Surgery, Royal Adelaide Hospital and University of Adelaide; ACRF Cancer Genomics Facility, Centre for Cancer Biology, Division of Tissue Pathology, SA Pathology; Centre for Neurological Diseases, Hanson Institute and SA Pathology; Department of Radiology, Queen Elizabeth Hospital; Department of Haematology and Oncology, Basil Hetzel Institute and Queen Elizabeth Hospital; University of Adelaide, Discipline of Surgery, Basil Hetzel Institute, Adelaide; Sarcoma Genomics and Genetics Laboratory, Peter MacCallum Cancer Centre, Melbourne, Australia; and Department of Medical Oncology, The Royal Melbourne Hospital, Parkville, Australia.
authors: Kathleen I
authors: KI
authors: Pishas
authors: Susan J
authors: SJ
authors: Neuhaus
authors: Mark T
authors: MT
authors: Clayer
authors: Andreas W
authors: AW
authors: Schreiber
authors: David M
authors: DM
authors: Lawrence
authors: Michelle
authors: M
authors: Perugini
authors: Robert J
authors: RJ
authors: Whitfield
authors: Gelareh
authors: G
authors: Farshid
authors: Jim
authors: J
authors: Manavis
authors: Steve
authors: S
authors: Chryssidis
authors: Bronwen J
authors: BJ
authors: Mayo
authors: Rebecca C
authors: RC
authors: Haycox
authors: Kristen
authors: K
authors: Ho
authors: Michael P
authors: MP
authors: Brown
authors: Richard J
authors: RJ
authors: D'Andrea
authors: Andreas
authors: A
authors: Evdokiou
authors: David M
authors: DM
authors: Thomas
authors: Jayesh
authors: J
authors: Desai
authors: David F
authors: DF
authors: Callen
authors: Paul M
authors: PM
authors: Neilsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D019175:DNA Methylation; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D044127:Epigenesis, Genetic; D057890:Epigenomics; D005260:Female; D005784:Gene Amplification; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics; D010879:Piperazines / Q000494:pharmacology* / Q000627:therapeutic use; D020641:Polymorphism, Single Nucleotide; D011379:Prognosis; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics; D012509:Sarcoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D059467:Transcriptome; D016896:Treatment Outcome; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D055815:Young Adult; D000097642:GADD45 Proteins
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D007093:Imidazoles; D009687:Nuclear Proteins; D010879:Piperazines; D051736:Proto-Oncogene Proteins c-mdm2; D016159:Tumor Suppressor Protein p53; C439070:GADD45A protein, human; D000097642:GADD45 Proteins; C482205:nutlin 3