title: Four clinically utilized drugs were identified and validated for treatment of adrenocortical cancer using quantitative high-throughput screening.
abstract: BACKGROUND
  Drug repurposing for cancer treatment is an emerging approach to discover clinically approved drugs that demonstrate antineoplastic effect. The effective therapeutics for patients with advanced adrenocortical carcinoma(ACC) are greatly needed. The objective of this study was to identify and validate drugs with antineoplastic effect in ACC cells using a novel quantitative high-throughput drug screening (qHTS) technique.
  
  
  METHODS
  A quantitative high-throughput proliferation assay of 2,816 clinically approved drugs was performed in the NCI-H295R ACC cell line. We validated the antiproliferative effect of candidate compounds in NCI-H295R cells. Further validation was performed in 3-dimensional multicellular aggregates (MCA) of NCI-H295R and SW-13 cell lines.
  
  
  RESULTS
  We identified 79 active compounds against ACC cells; 21 had an efficacy ≥ 60% and IC50 <1 μM. The top drug categories enriched were cardiotonic, antiseptic, and antineoplastic. We selected Bortezomib, ouabain, Methotrexate, pyrimethamine for validation. All had an antiproliferative effect in monolayer culture of NCI-H295R cells at clinical achievable serum level. Bortezomib and ouabain inhibited growth of MCA in both cell lines at a low concentration (10 fold below IC50). Methotrexate inhibited growth and caused disintegration of MCA in both cell lines at concentrations well below the maximum serum level (10 to 100 fold of IC50). Pyrimethamine caused growth inhibition in both cell lines at 10 fold of IC50 concentration.
  
  
  CONCLUSIONS
  qHTS of previously approved compounds is an effective and efficient method to identify anticancer drugs for a rare cancer such as ACC. We have validated the antineoplastic effect of Bortezomib, ouabain, Methotrexate and pyrimethamine, which could be translated into clinical trials in patients with locally advanced and/or metastatic ACC.
authors.affiliation: Endocrine Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 10 Center Drive, MSC 1201, Bethesda, MD 20892, USA. niluboln@mail.nih.gov
authors.forename: Naris
authors.initials: N
authors.lastname: Nilubol
authors.forename: Lisa
authors.initials: L
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Shen
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Mei
authors.initials: M
authors.lastname: He
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Austin
authors.forename: Electron
authors.initials: E
authors.lastname: Kebebew
mesh_terms: D000306:Adrenal Cortex Neoplasms / Q000188:drug therapy*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D057166:High-Throughput Screening Assays; D006801:Humans
chemical_list: D000970:Antineoplastic Agents; D053148:Caspase 3; D053179:Caspase 7