Mutated BRAF Emerges as a Major Effector of Recurrence in a Murine Melanoma Model After Treatment With Immunomodulatory Agents

Mol Ther. 2015 May;23(5):845-856. doi: 10.1038/mt.2014.253. Epub 2014 Dec 29.

Abstract

We used a VSV-cDNA library to treat recurrent melanoma, identifying immunogenic antigens, allowing us to target recurrences with immunotherapy or chemotherapy. Primary B16 melanoma tumors were induced to regress by frontline therapy. Mice with recurrent tumors were treated with VSV-cDNA immunotherapy. A Th17 recall response was used to screen the VSV-cDNA library for individual viruses encoding rejection antigens, subsequently targeted using immunotherapy or chemotherapy. Recurrent tumors were effectively treated with a VSV-cDNA library using cDNA from recurrent B16 tumors. Recurrence-associated rejection antigens identified included Topoisomerase-IIα, YB-1, cdc7 kinase, and BRAF. Fourteen out of 16 recurrent tumors carried BRAF mutations (595-605 region) following frontline therapy, even though the parental B16 tumors were BRAF wild type. The emergence of mutated BRAF-containing recurrences served as an excellent target for BRAF-specific immune-(VSV-BRAF), or chemo-(PLX-4720) therapies. Successful PLX-4720 therapy of recurrent tumors was associated with the development of a broad spectrum of T-cell responses. VSV-cDNA technology can be used to identify recurrence specific antigens. Emergence of mutated BRAF may be a major effector of melanoma recurrence which could serve as a target for chemo or immune therapy. This study suggests a rationale for offering patients with initially wild-type BRAF melanomas an additional biopsy to screen for mutant BRAF upon recurrence.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Animals
  • Antigens, Neoplasm / immunology
  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Agents / pharmacology
  • Base Sequence
  • Cancer Vaccines / genetics
  • Cancer Vaccines / immunology
  • Cell Line, Tumor
  • Disease Models, Animal
  • Drug Resistance, Neoplasm
  • Ganciclovir / pharmacology
  • Gene Expression
  • Humans
  • Immunologic Factors / administration & dosage
  • Immunologic Factors / pharmacology
  • Male
  • Melanoma / drug therapy
  • Melanoma / genetics*
  • Melanoma / immunology
  • Melanoma / pathology*
  • Melanoma, Experimental
  • Mice
  • Molecular Sequence Data
  • Mutation*
  • Neoplasm Recurrence, Local
  • Proto-Oncogene Proteins B-raf / chemistry
  • Proto-Oncogene Proteins B-raf / genetics*
  • Thymidine Kinase / genetics

Substances

  • Antigens, Neoplasm
  • Antineoplastic Agents
  • Cancer Vaccines
  • Immunologic Factors
  • Thymidine Kinase
  • Proto-Oncogene Proteins B-raf
  • Ganciclovir