title: Resistance mechanisms to TP53-MDM2 inhibition identified by in vivo piggyBac transposon mutagenesis screen in an Arf-/-mouse model.
abstract: Inhibitors of double minute 2 protein (MDM2)-tumor protein 53 (TP53) interaction are predicted to be effective in tumors in which theTP53gene is wild type, by preventing TP53 protein degradation. One such setting is represented by the frequentCDKN2Adeletion in human cancer that, through inactivation ofp14ARF, activates MDM2 protein, which in turn degrades TP53 tumor suppressor. Here we used piggyBac (PB) transposon insertional mutagenesis to anticipate resistance mechanisms occurring during treatment with the MDM2-TP53 inhibitor HDM201. Constitutive PB mutagenesis inArf-/-mice provided a collection of spontaneous tumors with characterized insertional genetic landscapes. Tumors were allografted in large cohorts of mice to assess the pharmacologic effects of HDM201. Sixteen out of 21 allograft models were sensitive to HDM201 but ultimately relapsed under treatment. A comparison of tumors with acquired resistance to HDM201 and untreated tumors identified 87 genes that were differentially and significantly targeted by the PB transposon. Resistant tumors displayed a complex clonality pattern suggesting the emergence of several resistant subclones. Among the most frequent alterations conferring resistance, we observed somatic and insertional loss-of-function mutations in transformation-related protein 53 (Trp53) in 54% of tumors and transposon-mediated gain-of-function alterations in B-cell lymphoma-extra large (Bcl-xL),Mdm4, and twoTP53family members, resulting in expression of the TP53 dominant negative truncationsΔNTrp63andΔNTrp73.Enhanced BCL-xL and MDM4 protein expression was confirmed in resistant tumors, as well as in HDM201-resistant patient-derived tumor xenografts. Interestingly, concomitant inhibition of MDM2 and BCL-xL demonstrated significant synergy in p53 wild-type cell lines in vitro. Collectively, our findings identify several potential mechanisms by whichTP53wild-type tumors may escape MDM2-targeted therapy.
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland; emilie.chapeau@novartis.com.
authors.forename: Emilie A
authors.initials: EA
authors.lastname: Chapeau
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Gembarska
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Eric Y
authors.initials: EY
authors.lastname: Durand
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Emeline
authors.initials: E
authors.lastname: Mandon
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Claire
authors.initials: C
authors.lastname: Estadieu
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Romanet
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Marion
authors.initials: M
authors.lastname: Wiesmann
authors.affiliation: Oncology Translational Research, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Ralph
authors.initials: R
authors.lastname: Tiedt
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, Cambridge, MA 02139.
authors.forename: Joseph
authors.initials: J
authors.lastname: Lehar
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Antoine
authors.initials: A
authors.lastname: de Weck
authors.affiliation: Department of Medicine II, Klinikum Rechts der Isar, Technische Universität München, 81675 Munich, Germany.|German Cancer Research Center (DKFZ) and German Cancer Consortium, 69120 Heidelberg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Rad
authors.affiliation: Oncology Translational Research, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Louise
authors.initials: L
authors.lastname: Barys
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Jeay
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Stephane
authors.initials: S
authors.lastname: Ferretti
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Audrey
authors.initials: A
authors.lastname: Kauffmann
authors.affiliation: Preclinical Safety, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Esther
authors.initials: E
authors.lastname: Sutter
authors.affiliation: Preclinical Safety, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Armelle
authors.initials: A
authors.lastname: Grevot
authors.affiliation: Preclinical Safety, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Pierre
authors.initials: P
authors.lastname: Moulin
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Masato
authors.initials: M
authors.lastname: Murakami
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, Cambridge, MA 02139.
authors.forename: William R
authors.initials: WR
authors.lastname: Sellers
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Francesco
authors.initials: F
authors.lastname: Hofmann
authors.affiliation: Oncology Disease Area, Novartis Institutes for BioMedical Research, 4056 Basel, Switzerland.
authors.forename: Michael Rugaard
authors.initials: MR
authors.lastname: Jensen
mesh_terms: D064591:Allografts; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D014408:Biomarkers, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D004251:DNA Transposable Elements; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D040961:Genetic Drift; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D053208:Kaplan-Meier Estimate; D051379:Mice; D018345:Mice, Knockout; D016254:Mutagenesis, Insertional; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D051736:Proto-Oncogene Proteins c-mdm2 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004251:DNA Transposable Elements; D016159:Tumor Suppressor Protein p53; D051020:bcl-X Protein; D051736:Proto-Oncogene Proteins c-mdm2
keywords: MDM2 inhibitor; cancer; drug resistance; piggyBac screen