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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
not stated
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: similarities to OECD test guideline 476 and data are scientifically acceptable

Data source

Reference
Reference Type:
publication
Title:
Platinum-induced mutations to 8-azaguanine resistance in Chinese hamster ovary cells.
Author:
Taylor R. T. et al.
Year:
1979
Bibliographic source:
Mutation Research 67, 65-80

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
GLP compliance:
not specified
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: In [presumably aqueous] solution
Details on test material:
Potassium hexachloroplatinate (CAS 16921-30-5)
Purchased from Chemical Procurement Labs, Inc.
Stored in the dark; CAS not provided.

Method

Target gene:
HGPRT locus
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
CHO-S cells, a proline-requiring Chinese Hamster Ovary cells adapted to suspension culture
Metabolic activation:
without
Test concentrations with justification for top dose:
Including 10 and 60 uM [possibly 1-100 µM]
Vehicle / solvent:
Presumably distilled water
Controls
Untreated negative controls:
yes
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Details on test system and experimental conditions:
Briefly, the test substance (or ethyl methanesulphonate) were added to exponentially growing cells, and the cultures were incubated at 37 deg C for 20 hours in the dark. The cells were then harvested by centrifugation and resuspended in mutagen-free medium at a density of 50,000/ml to begin the expression growth in suspension. Growth was monitored, and every 48 hours the cells were centrifuged and an aliqout transferred to fresh medium (50,000/ml) containing 10 µM of the test substance. After 5, 10, 15, 20 and 30 population doublings, the cells were harvested and plated for survival, and subcultured for mutant expression growth in fresh medium to determine the 8-AGR mutant frequency at the HGPRT locus [and possibly the OUAR mutants]; results were compared to control. It seems that the test substance was also tested at 60 µM and, after 7 population doublings, the OUAR and 8-AGR mutant frequencies were evaluated.
Evaluation criteria:
Only data for 10 and 60 uM are presented.
Resistant mutant frequencies were presumably compared to control.
Statistics:
None reported.

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
without
Genotoxicity:
positive
Remarks:
weak
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
not significant at 10 uM; growth/cloning efficiency reduced by 50% at 34/50 uM, respectively
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
A 2-3-fold increase in the 8-AGR mutant frequency versus the spontneous control was seen upon repeated subculture. This increase was apparent after 10 population doublings.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive without metabolic activation, weak with prolonged exposure

In a well-conducted in vitro mammalian gene mutation test using CHO cells, dipotassium hexachloroplatinate was weakly mutagenic when tested up to cytotoxic concentrations, in the absence of metabolic activation.
Executive summary:

Dipotassium hexachloroplatinate was tested for genotoxicity in an in vitro mammalian gene mutation test using Chinese Hamster Ovary (CHO) cells deficient in HPRT (hypoxanthine-guanine phosphoribosyl transferase). Cells were tested only in the absence of a metabolic activation system.

 

A 2-3-fold increase in the 8-AGR mutant frequency versus the spontaneous control was seen upon repeated subculture [prolonged exposure] with a non-cytotoxic concentration of 10 μM. This increase was apparent after 10 population doublings; the trend towards it was observed at 5 population doublings.