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ICCVAM has invited the nomination for validation studies of in vitro test methods that meet the recommendations
outlined in the ICCVAM Evaluation of In Vitro Methods for Detecting Potential Endocrine Disruptors. In response, CertiChem, Inc.,
(CertiChem) has nominated its
MCF-7 Cell Proliferation Assay. The assay measures whether, and to what extent, a substance induces cell
proliferation via estrogen receptor (ER)-mediated pathways using MCF-7 cells, an immortalized human breast adenocarcinoma cell line that
endogenously expresses ER. Validation studies to evaluate the performance of the assay in measuring estrogenic
and anti-estrogenic activity have been initiated at CertiChem's laboratories, and NICEATM is working closely with
CertiChem to ensure that the ICCVAM recommendations are followed during the validation studies.
Background
The MCF-7 Assay was developed by CertiChem, Inc., in collaboration with laboratories
at the University of Missouri and Northwestern University. The assay was further refined
by CertiChem Inc. with the support of NIH Phase I and II Small Business Innovative
Research (SBIR) grants awarded in 2001 and 2004 respectively. A background review document (BRD) was
prepared describing the historical development and rationale
for the assay's use in detecting estrogenic activity,
and results from testing done at all three facilities were presented in support of the assay.
In accordance with the ICCVAM nomination process, a pre-screen evaluation of the CertiChem BRD was conducted
to determine the extent to which:
- The BRD addressed ICCVAM prioritization criteria
- The BRD provided the information requested in the ICCVAM Guidelines for the Nomination and Submission of
New, Revised, and Alternative Test Methods
- The proposed test method adheres to the recommendations of the ICCVAM
Evaluation of In Vitro Test Methods
for Detecting Potential Endocrine Disruptors, especially those regarding essential
test method components
- The proposed test method showed adequate performance (reliability and accuracy) during pre-validation to
warrant consideration for validation studies
The pre-screen evaluation was made available to the public in October 2006,
and ICCVAM invited comments on whether the CertiChem MCF-7 Cell Proliferation Assay of
Estrogenic Activity should be considered for additional validation studies.
Public comments and recommendations from the Scientific Advisory Committee on Alternative Toxicological Methods were
considered and ICCVAM has recommended that the assay be given a high priority for additional validation.
CertiChem was also awarded Phase I (2006) and II (2007) SBIR grants to support the development
and testing of a protocol for the detection of anti-estrogenic activity based on the MCF-7 Cell
Proliferation Assay. The Phase II SBIR grant was supplemented in early 2008 to further support
testing of the previously developed protocol for the detection of estrogenic activity. CertiChem then
submitted a proposal to NICEATM requesting
support in designing studies for the validation of the MCF-7 Cell Proliferation Assay protocols for
both the detection of estrogenic and anti-estrogenic activity.
In response to this proposal, ICCVAM recommended that NICEATM should work closely with CertiChem
in the design of their validation studies. This collaboration would ensure that each of the ICCVAM-recommended
essential test method components for ER transcriptional activation assays are included, and that the
53 ICCVAM-recommended ER reference substances are used to assess
test method accuracy and reliability. In support of this recommendation, NICEATM is providing
CertiChem with coded samples of each of the compounds in the ICCVAM recommended minimum list.
The intralaboratory validation study has been initiated at CertiChem's laboratories. The study is being
conducted in a phased manner, first evaluating reference standards and controls and then
progressively testing subsets of coded reference substances from the ICCVAM recommended minimum
list. This phased approach is expected to identify and resolve sources of variation early in the
validation process and result in reproducible test method protocols that can be further validated by
testing in multiple laboratories.
Related Documents
Test Method Nomination for the MCF-7 Cell Proliferation Assay of Estrogenic Activity (January 2006) [PDF]
NICEATM Pre-Screen Evaluation of the In Vitro Endocrine Disruptor Assay
(Robotic MCF-7 Cell Proliferation Assay of Estrogenic Activity) (October 2006) [PDF]
Federal Register notice announcing the availability of the Pre-Screen Evaluation
(Vol. 71, No. 199, pp. 60748-60749, October 16, 2006)
[PDF]
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