2-(m-benzoylphenyl)propionitrile

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / micronucleus study

Remarks:

Type of genotoxicity: other: Test of clastogenicity and aneugenicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 1 March 2011 to 7 April 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: OECD guideline 487 but no reference on GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD guideline 487 dated 22 July 2010

Principles of method if other than guideline:

Micronuclei detected in the cytoplasm of interphase cells, result from either chromosome breakage leading to acentric fragments (clastogenicity) or impairment of the structure and/or function of the mitotic apparatus leading to lagging chromosomes (aneugenicity).

GLP compliance:

no

Type of assay:

in vitro mammalian cell micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

42872-30-3

IUPAC Name:

42872-30-3

Constituent 2

Reference substance name:

2-(m-benzoylphenyl)propionitrile

EC Number:

255-982-5

EC Name:

2-(m-benzoylphenyl)propionitrile

Cas Number:

42872-30-0

Molecular formula:

C16H13NO

IUPAC Name:

2-(3-benzoylphenyl)propanenitrile

Details on test material:

Test article identification: BPPN
Test article batch number: F-CHN-090031-01
Certificate of analysis: dated 08 February 2011

Method

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Metabolic activation system:

S9-mix from the liver of Aroclor 1254-treated rats (final percentage of S9-mix in the culture medium:1.5%)

Test concentrations with justification for top dose:

With metabolic activation:
Range of concentrations tested in the culture medium: from 1 to 50 μg/mL.
The evaluated concentrations were 10, 20 and 25 μg/mL.
Without metabolic activation
Range of concentrations tested in the culture medium: from 1 to 600 μg/mL.
The evaluated concentrations were 10, 30 and 60 μg/mL.

Vehicle / solvent:

dimethyl sulfoxide (DMSO)

Controls

Untreated negative controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

cyclophosphamide

mitomycin C

Remarks:

Without metabolic activation: Mitomycin C (MITC), 0.01 μg/mL With metabolic activation: Cyclophosphamide (CP), 1.5 μg/mL

Details on test system and experimental conditions:

L5178Y cells were treated with the substance in 96-well microtiter plates for 3 hours with metabolic activation and for 28 hours without metabolic activation. Without metabolic activation the cells were harvested directly after the treatment time and with metabolic activation 21 hours (recovery time) after the end of the treatment.

Evaluation criteria:

Experiment acceptance criteria
The experiment is considered valid when all the following criteria are fulfilled:
• the population doubling of the negative control is higher or equal to 1.5 but not higher than 2.2;
• the number of micronucleated cells per 1000 cells in the concurrent solvent control is lower than or equal to the acceptable upper value for historical solvent control data (99% percentile of our historical negative control data):
- 9 for 28-hour treatment without S9-mix;
- 11 for 3-hour treatment with S9-mix.
• the positive controls induce a marked increase in the number of micronucleated cells;
• at least three analyzable concentrations are scored;
• the highest concentration evaluated corresponds either to 5000 µg/mL (or 10mM), or to the solubility limit in the solvent, or to the lowest precipitating concentration in the culture medium or to 50% to 60% of cell cytotoxicity.

Test evaluation criteria
A test article is considered to induce a positive response in the in vitro micronucleus test if the two criteria listed below are fulfilled for at least one concentration:
• the test article induces a statistically significant increase in the number of micronucleated cells for a given concentration;
• for this concentration, this value is strictly above positive threshold value (99% percentile of our historical negative control data):
- 9 for 28-hour treatment without S9-mix;
- 11 for 3-hour treatment with S9-mix.
When none of the above criteria are fulfilled, the test article is considered negative.

Results and discussion

Test results

Test results 1

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

A significant increase in the number of micronucleated cells was observed at 20 and 25 μg/mL.

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The top concentration retained for scoring 25 μg/mL (60% of cytotoxicity) corresponded to the required cytotoxicity (50% to 60%).

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

No significant increase in the number of micronucleated cells was observed.

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The top concentration retained for scoring 60 μg/mL (55% of cytotoxicity) corresponded to the required cytotoxicity (50% to 60%).

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Additional information on results:

Preliminary test
With metabolic activation (3-hour treatment and 21-hour recovery):
Range of concentrations tested in the culture medium: from 1 to 600 μg/mL.
The evaluated concentrations were 10, 20 and 30 μg/mL.
The top concentration retained for scoring 30 μg/mL (42% of cytotoxicity) was considered as corresponding to the required cytotoxicity (50% to 60%) as the slides presented damaged cells with vacuoles attesting for cytotoxicity.
Genotoxicity
A significant increase in the number of micronucleated cells was observed at the three concentrations.
Another test was performed to confirm this result.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative without metabolic activation
positive with metabolic activation

Under the experimental conditions of this study, BPPN was found positive in the exploratory in vitro micronucleus test in mouse lymphoma cells in the presence of metabolic activation and negative in the absence of metabolic activation.