National Toxicology Program

Overview

U.S. Federal agencies have agreed with ICCVAM recommendations on the use of human cell-based test methods to screen for substances with the potential to interact with the estrogen receptor. ICCVAM evaluated the scientific validity of the BG1Luc estrogen receptor (ER) transactivation (TA) agonist and antagonist assays and recommended how they could be used to identify substances that induce or inhibit human ER activity in vitro. The U.S. Environmental Protection Agency (EPA) responded that they regard the BG1Luc ER TA test method as an alternative to the ER TA test method currently used in their Endocrine Disruptor Screening Program. Several other Federal agencies also indicated that they would communicate the ICCVAM recommendations to stakeholders and encourage appropriate use of the recommended methods.

ICCVAM developed the recommendations on the BG1Luc ER TA assays after considering the comments of an international independent peer review panel that met in 2011, as well as comments from the public and the Scientific Advisory Committee on Alternative Toxicological Methods. ICCVAM recommended that the BG1Luc ER TA test methods may be used as screening tests to identify substances with in vitro ER agonist or antagonist activity.

ICCVAM concluded that the accuracy of the BG1 ER TA agonist assay is at least equivalent to the only ER TA test method currently in a U.S. regulatory test guideline, the EPA’s “OPPTS 890.1300: Estrogen Receptor Transcriptional Activation (Human Cell Line (HeLa-9903))”. The BG1Luc ER TA test method was found to offer several advantages over the existing ER TA method, including (1) validation for use over a wider concentration range of test substances, (2) potential to detect a wider range of ER-active substances, (3) ability to identify both substances that induce and inhibit the estrogen receptor, and (4) availability of the cell line used for the test from more than one source.

See below for letters to Federal agencies communicating ICCVAM recommendations and agency responses

Background on the BG1Luc ER TA Test Method Validation Study

In 2003, ICCVAM evaluated the validation status of in vitro ER and androgen receptor (AR) binding and TA test methods for potential use in the EPA's Endocrine Disruptor Screening Program. The evaluation indicated that there were no in vitro ER- or AR-based test methods that were adequately validated for this purpose. In response to an ICCVAM request for nominations of test methods, the BG1Luc ER TA was nominated to ICCVAM for a validation study.

The BG1Luc ER TA test method (also known as the LUMI-CELL^® test method) was developed by Xenobiotic Detection Systems, Inc., with support from a Small Business Innovation Research grant from the National Institute of Environmental Health Sciences. The test method measures the extent to which a substance induces or inhibits TA activity via ER-mediated pathways in recombinant BG1Luc4E2 cells.

The BG1Luc4E2 cell line was derived from BG-1 immortalized adenocarcinoma cells that endogenously express both human ER forms, ERα and ERβ and that have been stably transfected with the plasmid pGudLuc7.ERE. This plasmid contains four copies of a synthetic oligonucleotide containing the estrogen response element upstream of the mouse mammary tumor viral promoter and the firefly luciferase gene. BG-1Luc4E2 cells emit measurable light in response to estrogen and estrogen-like substances.

NICEATM coordinated an international interlaboratory validation study of the BG1Luc ER TA test method. The goal of the validation study, which was completed in 2010, was to evaluate the usefulness of the BG1Luc ER TA test method as a screening test to identify substances with in vitro ER agonist and antagonist activity. The international validation study of the BG1Luc ER TA test method included participating laboratories located in Italy, the U.S., and Japan. It was the first validation study sponsored jointly by ICCVAM, the European Centre for the Validation of Alternative Methods (now known as the European Union Reference Laboratory for Alternatives to Animal Testing), and the Japanese Center for the Validation of Alternative Methods.

Peer Review of the BG1Luc ER TA Validation Study

In a March 2011 public meeting, an independent international peer review panel agreed with ICCVAM draft test method recommendations stating that an in vitro test method may be used as an initial screen to identify substances with the potential to enhance or inhibit activation of the estrogen receptor. The panel of 16 expert scientists from six countries reviewed data from the validation study, made recommendations on future studies that could further enhance the usefulness of this test method, and commented on draft performance standards that could be used to expedite the evaluation of similar test methods.

Read the peer review panel report (May 2011)

Corrections to the Peer Review Panel Report (August 2011)
This document lists changes made to the report by the peer review panel members that were inadvertently omitted in the printed version of the report. The electronic version of the report available above includes these corrections. If you have a printed copy of this report, please print this document and keep it with the printed report. We apologize for any inconvenience.

Read a summary of the March 2011 peer review panel meeting

View agenda for the peer review panel meeting

BG1Luc ER TA Submitted to Tox21

NICEATM also nominated the BG1Luc ER TA test methods for evaluation in Tox21. The assays have now been adapted to a high throughput format using 1536-well plates by the National Center for Advancing Translational Sciences and have been used to screen all compounds in the Tox21 10K chemical library.
Read more about the Tox21 program

Transmittal of Recommendations to Federal Agencies

• National Institute of Environmental Health Sciences (NIEHS)
  
  • Letter from Linda Birnbaum, Ph.D., DABT, ATS, Director, NIEHS, to the ICCVAM Committee (April 18, 2012) [PDF]


• Agency for Toxic Substances and Disease Registry (ATSDR)
  
  • Letter from Linda Birnbaum, Ph.D., Director of NIEHS and NTP, to Thomas R. Frieden, M.D., M.P.H., Director, Centers for Disease Control, and Administrator, ATSDR [PDF]
  • Response from Dr. Frieden (received August 3, 2012) [PDF]


• Consumer Product Safety Commission (CPSC)
  
  • Letter from Dr. Birnbaum to Inez Moore Tenenbaum, Chairman, CPSC [PDF]
  • Response from Kenneth R. Hinson, Executive Director (received July 23, 2012) [PDF]


• Environmental Protection Agency (EPA)
  
  • Letter from Dr. Birnbaum to Lisa P. Jackson, Administrator, EPA [PDF]
  • Response from Frank T. Sanders, Director, Office of Science Coordination and Policy (received July 17, 2012) [PDF]


• Food and Drug Administration (FDA)
  
  • Letter from Dr. Birnbaum to Margaret Hamburg, M.D., Commissioner [PDF]
  • Response from Jesse L. Goodman, M.D., M.P.H. , Chief Scientist and Deputy Commissioner for Science and Public Health (received March 9, 2012) [PDF]


• National Cancer Institute (NCI)
  
  • Letter from Dr. Birnbaum to Harold Varmus, M.D., Director, NCI [PDF]
  • Response from Dr. Varmus (received February 7, 2012) [PDF]


• National Institutes of Health (NIH)
  
  • Letter from Dr. Birnbaum to Francis S. Collins, M.D., Ph.D., Director, NIH [PDF]
  • Response from Dr. Collins (received June 26, 2012) [PDF]


• National Institute for Occupational Safety and Health (NIOSH)
  
  • Letter from Dr. Birnbaum to John Howard, M.D., Director, NIOSH [PDF]
  • Response from Dr. Howard (received June 26, 2012) [PDF]


• National Library of Medicine (NLM)
  
  • Letter from Dr. Birnbaum to Donald A.B. Lindberg, M.D., Director, NLM [PDF]
  • Response from Dr. Lindberg (received June 2012) [PDF]


• Occupational Safety and Health Administration (OSHA)
  
  • Letter from Dr. Birnbaum to David Michaels, Ph.D., M.P.H., Assistant Secretary of Labor for Occupational Safety and Health, OSHA [PDF]
  • Response from Dr. Michaels (received July 17, 2012) [PDF]


• U.S. Department of Agriculture
  
  • Letter from Dr. Birnbaum to Tom Vilsack, Secretary of Agriculture [PDF]
  • Response from Kevin Shea, Acting Administrator, Animal and Plant Health Inspection Service (received July 17, 2012) [PDF]


• U.S. Department of Defense
  
  • Letter from Dr. Birnbaum to Leon E. Panetta, Secretary of Defense [PDF]
  • Response from Patrick Mason, Ph.D., SES, Director, Human Performance, Training, and BioSystems (received April 30, 2012) [PDF]


• U.S. Department of Energy
  
  • Letter from Dr. Birnbaum to Steven Chu, Secretary of Energy [PDF]
  • Response from Dr. Michael Kuperberg, Office of Biological and Environmental Research (received March 19, 2012) [PDF]


• U.S. Department of the Interior
  
  • Letter from Dr. Birnbaum to Ken Salazar, Secretary of the Interior [PDF]
  • Response from David Russ, Regional Executive, Northeast Area, U.S. Geological Survey (received July 9, 2012) [PDF]


• U.S. Department of Transportation
  
  • Letter from Dr. Birnbaum to Ray LaHood, Secretary of Transportation [PDF]
  • Response from Cynthia Quarterman, Pipeline and Hazardous Materials Safety Administration (received July 3, 2012) [PDF]

Other Materials Relevant to the BG1Luc ER TA Test Method Validation Study

• Submission Package [PDF]
• Letter Accompanying Submission Package from Drs. George Clark and John Gordon, XDS, Inc. [PDF]

• LUMI-CELL^® ER Agonist Protocol (updated March 2009) [PDF]
• LUMI-CELL^® ER Antagonist Protocol (updated March 2009) [PDF]

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