3,3'-thiodi(propionic acid)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

consistently negative in all tests:

Bacterial reverse mutation assay (equivalent to OECD TG 471)

in vitro chromosome aberration study in mammalian cells (equivalent to OECD TG 473)

in vitro mammalian cell gene mutation test (QSAR)

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

1. SOFTWARE
Danish (Q)SAR Database, http://qsar.food.dtu.dk, including CASE Ultra, Leadscope, SciQSAR

2. MODEL (incl. version number)
MultiCASE CASE Ultra 1.4.6.6
Leadscope Predictive Data Miner, a component of Leadscope Enterprise version 3.1.1‐10
SciQSAR version 3.1.00

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C(=O)(O)CCSCCC(=O)O

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
see attached QMRF documents

5. APPLICABILITY DOMAIN
see attached QMRF documents

6. ADEQUACY OF THE RESULT
The substance falls into the applicability domains of the models. The results of the different models were consistent (all predictions were negative). Thus, the result is considered to be reliable and adequate for hazard assessment.

Principles of method if other than guideline:

QSAR models (battery of CASE Ultra, Leadscope, SciQSAR provided by Danish (Q)SAR Database, http://qsar.food.dtu.dk)

GLP compliance:

no

Remarks:

no applicable for in silico study

Type of assay:

other: in vitro mammalian cell gene mutation tests using the thymidine kinase gene / in vitro mammalian cell gene mutation test using the Hprt gene

Target gene:

TK, HGPRT

Test concentrations with justification for top dose:

n.a.

Vehicle / solvent:

n.a.

Details on test system and experimental conditions:

n.a.

Rationale for test conditions:

n.a.

Evaluation criteria:

n.a.

Statistics:

n.a.

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

not specified

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Remarks:

in silico study

Vehicle controls validity:

not specified

Remarks:

in silico study

Untreated negative controls validity:

not specified

Remarks:

in silico study

True negative controls validity:

not specified

Remarks:

in silico study

Positive controls validity:

not specified

Remarks:

in silico study

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

not specified

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Remarks:

in silico study

Vehicle controls validity:

not specified

Remarks:

in silico study

Untreated negative controls validity:

not specified

Remarks:

in silico study

True negative controls validity:

not specified

Remarks:

in silico study

Positive controls validity:

not specified

Remarks:

in silico study

Additional information on results:

n.a.

Remarks on result:

no mutagenic potential (based on QSAR/QSPR prediction)

	Battery	CASE Ultra	Leadscope	SciQSAR
Mutations in Thymidine Kinase Locus in Mouse Lymphoma Cells	Negative (in applicability domain)	Negative (in applicability domain)	Negative (in applicability domain)	Negative (in applicability domain)
Mutations in HGPRT Locus in Chinese Hamster Ovary (CHO) Cells	Negative (in applicability domain)	Negative (in applicability domain)	Negative (in applicability domain)	Negative (in applicability domain)

Conclusions:

Interpretation of results: negative

Executive summary:

3,3'-Thiobispropanoic acid is predicted to be non-mutagenic in the in vitro mammalian cell gene mutation test using the thymidine kinase gene (in Mouse Lymphoma Cells) or the Hprt gene (Chinese Hamster Ovary (CHO) Cells). The prediction was made by QSAR using the Danish (Q)SAR Database, which uses CASE Ultra, Leadscope, SciQSAR.

The substance falls in the applicability domain of the models. The prediction was consistently negative for all models.

Reference 2

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions. Only translated summary available, actual guideline not stated.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

Only summary available, guideline not stated

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine operon for TA100, TA98,TA1535, TA1537, tryptophan operon for E. coli WP2 uvrA

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

156, 313, 625, 1250, 2500, 5000µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

with S9-mix Migrated to IUCLID6: 5µg/plate for TA 98, TA 100, TA 1537

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminanthrazene, 2µg/plate for TA 1535 and 10µg/plate for E. coli WP2 uvrA

Remarks:

with S9-mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, 0.01µg/plate for E. coli WP2 uvrA and TA 100 and 0.1µg/plate for TA 98

Remarks:

without S9-mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without S9-mix Migrated to IUCLID6: 0.5µg/plate for TA 1535

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-methoxy-6-chloro-9-[3-(2-chloroethyl)-aminopropylamino] acridine·2HCl, 1µg/plate for TA 1537

Remarks:

without S9-mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium; in agar (plate incorporation) with preincubation

DURATION
- Preincubation period: 20min
- Exposure duration: 48h

NUMBER OF REPLICATIONS: 3

NUMBER OF CELLS EVALUATED: no data

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth by colonie count

Evaluation criteria:

The test was determined to be positive if the number of revertant colonies was nearly double or above that of the solvent control and this was found to be reproducible and to be dependant on the dosage of the test material.

Statistics:

Statistical methods were not used

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: no

RANGE-FINDING/SCREENING STUDIES:
The results of the dose-range finding test and main test did not find growth inhibition or deposition of precipitation/crystals in regards to the test strains at any concentration regardless of the strain type or whether or not there was metabolic activation.

Table 1: Maximum revertant counts

	Maximum number of revertants with
	solvent Control		positive control		Treatment (at dose level [µg/mL])
Strain	With S9	Without S9	With S9	Without S9	With S9	Without S9
TA 100	126	106	529	884	120 (2500)	118 (625)
TA 1535	8	13	91	1329	11 (313)	12 (313)
E. coli WP2	26	31	180	635	33 (313)	29 (1250)
TA 98	25	15	318	603	28 (313)	16 (1250)
TA 1537	12	15	93	2480	18 (313)	17 (625)

From the above results, it was determined that under these test conditions 3,3’-thiobispropanoic acid does not induce genetic mutations on bacteria.

Conclusions:

Interpretation of results: negative

Executive summary:

In a bacterial reverse mutation assay equivalent to OECD TG 471 S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A were exposed to 3,3’-thiobispropanoic acid at concentrations of 0 (control), 156, 313, 625, 1250, 2500, 5000 µg/mL in DMSO. The test was performed as plate incoporation and pre-incubation assay. Cytotoxicity was not observed. The test item did not induce revertants above background. Thus, 3,3’-thiobispropanoic acid is not mutagenic in this assay.

Reference 3

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions. Only translated summary available, actual guideline not stated.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

yes

Remarks:

translated study summary, guideline not stated

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

13.9, 27.8, 55.6, 111, 223, 445, 890, 1780µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

with S9-mix Migrated to IUCLID6: 15µg/mL

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without S9-mix Migrated to IUCLID6: 0.05µg/mL

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 6h with and without S9-mix and 24 and 48h without S9-mix
- Expression time (cells in growth medium): 18h for 6h short term exposure
- Fixation time (start of exposure up to fixation or harvest of cells): 2h

SPINDLE INHIBITOR (cytogenetic assays): colcemid 0.2 μg/mL
STAIN (for cytogenetic assays): giemsa 2%

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: 100/plate

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

OTHER EXAMINATIONS:
- Determination of polyploidy: Yes

Evaluation criteria:

In accordance with the standard of Ishidate et al, the results were negative (-) when the appearance frequency of cells with chromosomal aberrations is under 5%, pseudo-positive (±) when 5% to under 10%, and positive (+) when 10% and above. In the end, the results were determined to be positive when the appearance of abnormal cells was found to be dependent on dosage
or repeatable.

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

The 50% cell growth inhibition concentration was 1780 μg/mL (comparable to 10 mM) and above for both the short-term treatment and continuous treatment regardless of whether the S9 mix was present.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES:
The test material cell growth inhibition action was used as an index by using a monolayer culture cell density meter (Monocellater, Olympus Optical Co., Ltd.) to measure and compare the cell densities of the test material treated group to those of the negative (medium) control group. The results showed that the 50% cell growth inhibition concentration was 1,780 μg/mL (comparable to 10 mM) and above for both the short-term treatment and continuous treatment regardless of whether the S9 mix was present.

Table 1: Effects on chromosomes

Conc. µg/mL	Cell growth [%]	% Cells showing
		Chromosome aberrations (with gaps)	Chromosome aberrations (without gaps)	Polyploidy
6h with S9-mix
0	100	0.0	0.0	0.0
111	87	0.5	0.0	0.5
223	74	1.0	0.0	1.0
445	99	1.5	0.0	0.5
890	99	0.5	0.0	1.5
1780	74	1.0	0.0	2.5
pos. control	/	76.5	76.0	0.5
6h without S9-mix
0	100	2.0	0.5	0.5
111	99	0.5	0.0	2.0
223	99	1.5	0.5	0.0
445	87	0.5	0.0	0.5
890	99	0.5	0.0	0.5
1780	87	1.0	0.5	1.0
pos. control	/	17.0	13.5	0.5
24h without S9-mix
0	100	4.5	1.5	0.5
111	99	2.5	1.0	1.0
223	99	2.0	1.0	0.0
445	99	4.5	1.5	1.0
890	99	2.5	1.0	0.5
1780	74	3.5	1.5	0.5
pos. control	/	36.0	33.0	0.0
48h without S9-mix
0	100	3.5	1.0	0.0
111	107	1.5	0.5	0.5
223	100	3.0	0.5	0.0
445	100	1.5	1.0	0.5
890	107	3.5	2.0	0.5
1780	78	6.0	3.0	0.0
pos. control	/	52.0	49.5	0.0

From the above results, it was determined that under these test conditions 3,3’-thiobispropanoic acid does not induce chromosomal aberrations and is non-clastogenic in chinese hamster lung fibroblast.

Conclusions:

Interpretation of results: negative

Executive summary:

In an in vitro mammalian chromosome aberration test equivalent to OECD TG 473 Chinese hamster lung fibroblasts (V79) were exposed to 3,3’-thiobispropanoic acid at concentrations of 0 (control), 13.9, 27.8, 55.6, 111, 223, 445, 890, 1780 µg/mL in DMSO with and without metabolic activation (S9 mix).

Cells were exposed for 6 h with and without S9-mix and 24 and 48 h without S9-mix.

Cytotoxicity was observed at 1780 μg/mL. The test item did not induce chromosome aberrations above background. Thus, 3,3’-thiobispropanoic acid is not clastogenic in this assay when tested up to cytotoxic concentrations.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Bacterial reverse mutation assay

In a bacterial reverse mutation assay equivalent to OECD TG 471 S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A were exposed to 3,3’-thiobispropanoic acid at concentrations of 0 (control), 156, 313, 625, 1250, 2500, 5000 µg/mL in DMSO. The test was performed as plate incoporation and pre-incubation assay. Cytotoxicity was not observed. The test item did not induce revertants above background. Thus, 3,3’-thiobispropanoic acid is not mutagenic in this assay.

 

in vitro chromosome aberration study in mammalian cells

In an in vitro mammalian chromosome aberration test equivalent to OECD TG 473 Chinese hamster lung fibroblasts (V79) were exposed to 3,3’-thiobispropanoic acid at concentrations of 0 (control), 13.9, 27.8, 55.6, 111, 223, 445, 890, 1780 µg/mL in DMSO with and without metabolic activation (S9 mix).

Cells were exposed for 6 h with and without S9-mix and 24 and 48 h without S9-mix.

Cytotoxicity was observed at 1780 μg/mL. The test item did not induce chromosome aberrations above background. Thus, 3,3’-thiobispropanoic acid is not clastogenic in this assay when tested up to cytotoxic concentrations.

 

in vitro mammalian cell gene mutation test

3,3'-Thiobispropanoic acid is predicted to be non-mutagenic in the in vitro mammalian cell gene mutation test using the thymidine kinase gene (in Mouse Lymphoma Cells) or the Hprt gene (Chinese Hamster Ovary (CHO) Cells). The prediction was made by QSAR using the Danish (Q)SAR Database, which uses CASE Ultra, Leadscope, SciQSAR.

The substance falls in the applicability domain of the models. The prediction was consistently negative for all models.

Justification for classification or non-classification

Based on the available data, 3,3'-Thiobispropanoic acid does not need to be classified for genetic toxicity according to regulation (EC) 1272/2008. Thus, no labelling is required.