Multidimensional Screening Platform for Simultaneously Targeting Oncogenic KRAS and Hypoxia-Inducible Factors Pathways in Colorectal Cancer

ACS Chem Biol. 2016 May 20;11(5):1322-31. doi: 10.1021/acschembio.5b00860. Epub 2016 Mar 3.

Abstract

Colorectal cancer (CRC) is a genetic disease, due to progressive accumulation of mutations in oncogenes and tumor suppressor genes. Large scale genomic sequencing projects revealed >100 mutations in any individual CRC. Many of these mutations are likely passenger mutations, and fewer are driver mutations. Of these, activating mutations in RAS proteins are essential for cancer initiation, progression, and/or resistance to therapy. There has been significant interest in developing drugs targeting mutated cancer gene products or downstream signaling pathways. Due to the number of mutations involved and inherent redundancy in intracellular signaling, drugs targeting one mutation or pathway have been either ineffective or led to rapid resistance. We have devised a strategy whereby multiple cancer pathways may be simultaneously targeted for drug discovery. For proof-of-concept, we targeted the oncogenic KRAS and HIF pathways, since oncogenic KRAS has been shown to be required for cancer initiation and progression, and HIF-1α and HIF-2α are induced by the majority of mutated oncogenes and tumor suppressor genes in CRC. We have generated isogenic cell lines defective in either oncogenic KRAS or both HIF-1α and HIF-2α and subjected them to multiplex genomic, siRNA, and high-throughput small molecule screening. We have identified potential drug targets and compounds for preclinical and clinical development. Screening of our marine natural product library led to the rediscovery of the microtubule agent dolastatin 10 and the class I histone deacetylase (HDAC) inhibitor largazole to inhibit oncogenic KRAS and HIF pathways. Largazole was further validated as an antiangiogenic agent in a HIF-dependent manner in human cells and in vivo in zebrafish using a genetic model with activated HIF. Our general strategy, coupling functional genomics with drug susceptibility or chemical-genetic interaction screens, enables the identification of potential drug targets and candidates with requisite selectivity. Molecules prioritized in this manner can easily be validated in suitable zebrafish models due to the genetic tractability of the system. Our multidimensional platform with cellular and organismal components can be extended to larger scale multiplex screens that include other mutations and pathways.

Publication types

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

MeSH terms

  • Angiogenesis Inhibitors / chemistry
  • Angiogenesis Inhibitors / pharmacology
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Basic Helix-Loop-Helix Transcription Factors / antagonists & inhibitors
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Biological Products / chemistry
  • Biological Products / pharmacology
  • Colon / drug effects
  • Colon / metabolism
  • Colon / pathology
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology
  • Drug Screening Assays, Antitumor / methods
  • Gene Knockout Techniques
  • HCT116 Cells
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / antagonists & inhibitors
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • RNA Interference
  • RNA, Small Interfering / genetics
  • Rectum / drug effects
  • Rectum / metabolism
  • Rectum / pathology
  • Signal Transduction / drug effects
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*
  • Transcriptome / drug effects
  • Zebrafish

Substances

  • Angiogenesis Inhibitors
  • Antineoplastic Agents
  • Basic Helix-Loop-Helix Transcription Factors
  • Biological Products
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • KRAS protein, human
  • RNA, Small Interfering
  • Small Molecule Libraries
  • endothelial PAS domain-containing protein 1
  • Proto-Oncogene Proteins p21(ras)