National Toxicology Program

Overview

NICEATM coordinated an international interlaboratory validation study of the BG1Luc estrogen receptor (ER) transcriptional activation (TA) test method developed by Xenobiotic Detection Systems, Inc. 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.

An ICCVAM-sponsored independent peer review panel met in March 2011 to review the results of the BG1Luc ER TA test method validation study. After considering the recommendations of the independent peer review panel, as well as comments from the public and the Scientific Advisory Committee on Alternative Toxicological Methods, ICCVAM recommended that the BG1Luc ER TA test method may be used as a screening test to identify substances with in vitro ER agonist and/or antagonist activity. ICCVAM concluded that the accuracy of this assay is at least equivalent to the only ER TA test method currently in a U.S. regulatory test guideline, the Environmental Protection Agency’s “OPPTS 890.1300: Estrogen Receptor Transcriptional Activation (Human Cell Line (HeLa-9903))”. In addition, 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.

The ICCVAM recommendations on the BG1Luc ER TA test method were formally transmitted to U.S. Federal agencies in February 2012. The ICCVAM Authorization Act of 2000 requires agencies to review the recommendations and respond to ICCVAM within 180 days.

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

Read the Federal Register notice announcing the transmittal of ICCVAM recommendations on the BG1Luc ER TA test method to Federal agencies [PDF - HTM]

Read a summary of the March 29-30 Peer Review Panel meeting [PDF]

View information about the Panel meeting and draft documents reviewed by the Panel

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 U.S. Environmental Protection Agency (EPA) 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., as part of a Small Business Innovation Research grant from the National Institute of Environmental Health Sciences. The test method measures whether and to what extent 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 express luciferase activity in response to estrogen and estrogen-like substances.

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 NICEATM-ICCVAM, the European Centre for the Validation of Alternative Methods, and the Japanese Center for the Validation of Alternative Methods.

The specific objectives of the validation study of the BG1Luc ER TA test method were to:

• Further standardize and optimize the BG1Luc ER TA test method using the agonist and antagonist protocols to test 78 ICCVAM-recommended substances for the validation of in vitro ER TA test methods in three laboratories to maximize test method reliability (intralaboratory repeatability, intra- and inter-laboratory reproducibility)
• Use the results from the testing of the 78 ICCVAM recommended substances to develop a high quality in vitro ER TA database that can be used to characterize the extent to which other individual in vitro endocrine disruptor test methods (or test method batteries) might be used to further reduce the expected requirements for animal use in the screening of potential endocrine disruptors

BG1Luc ER TA Submitted to Tox21

As we move towards the Toxicology in the 21st Century (Tox21) goal of pathways-based in vitro screens, the ability of test methods to be run on a high-throughput screening (HTS) platform is an important aspect of their potential utility. The BG1Luc ER TA test method has been adapted to a HTS format using 1536-well plates by the NIH Center for Translational Therapeutics (NCTT; formerly the NIH Chemical Genomics Center). Preliminary results are promising, and it is expected that this method will be incorporated into the Tox21 screening paradigm in 2012.

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]


• Consumer Product Safety Commission (CPSC)
  
  • Letter from Dr. Birnbaum to Inez Moore Tenenbaum, Chairman, CPSC [PDF]


• Environmental Protection Agency (EPA)
  
  • Letter from Dr. Birnbaum to Lisa P. Jackson, Administrator, EPA [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]


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


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


• U.S. Department of Agriculture
  
  • Letter from Dr. Birnbaum to Tom Vilsack, Secretary of Agriculture [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]


• U.S. Department of Transportation
  
  • Letter from Dr. Birnbaum to Ray LaHood, Secretary of Transportation [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]

The links listed below connect to pages outside the NICEATM-ICCVAM website. These links are for the convenience of visitors to this page, who may find them useful. NICEATM-ICCVAM is not responsible for the availability or content of these external sites, nor do we endorse, warrant or guarantee any information or any products or services described or offered at these other sites.