Chemical Activated LUciferase gene eXpression

Commonly used acronym: CALUX

Scope of the method

The Method relates to
  • Environment
  • Human health
The Method is situated in
  • Basic Research
  • Education and training
  • Regulatory use - Routine production
  • Translational - Applied Research
Type of method
  • In vitro - Ex vivo
This method makes use of
  • Human derived cells / tissues / organs
Specify the type of cells/tissues/organs
Both human (breast cancer) and animal (mouse hepatoma)

Description

Method keywords
  • in vitro bioassay
  • endocrine activity
  • bio-equivalent concentration
  • estrogen receptor
  • androgen receptor
  • aryl hydrocarbon receptor
  • mixture effects
  • Endocrine disrupting chemicals
Scientific area keywords
  • Toxicology
  • Environmental health
  • human health
  • Endocrine disrupting chemicals
Method description

The CALUX method is an in vitro bioassay that uses reporter gene cell lines that have been stably transfected with a luciferase reporter gene under the control of relevant receptor specific DNA response element. This enables the screening for chemicals that can bind to specific receptors and activate transcription. This activation will lead to the production of luciferase, and the amount of induced luciferase is directly proportional to the concentration and potency of the inducing chemical(s)/samples to which the cells have been exposed. CALUX is a semi-quantitative method, where a BEQ (bio-equivalent concentration) can be determined relative to a standard.

Lab equipment
  • - Class II microbiological Safety cabinet,
  • - Incubator (humidity 80%, 5%CO2),
  • - Luminometer to measure luciferase activity.

Pros, cons & Future potential

Advantages
  • - You measure the overall activity, so you take mixture effects into account ;
  • - Relatively cheap ;
  • - Can be used as a quick screening method for endocrine activity.
Challenges
  • - No identification, you measure the overall activity of a sample ;
  • - You measure the activity on a receptor, you don't know anything about endocrine disruption in vivo.

References, associated documents and other information

References
  • Boonen, I., Van Heyst, A., Van Langenhove, K., Van Hoeck, E., Mertens, B., Denison, M. S., ... & Demaegdt, H. (2020). Assessing the receptor-mediated activity of PAHs using AhR-, ERα-and PPARγ-CALUX bioassays. Food and Chemical Toxicology, 111602.
  • Guo, W., Van Langenhove, K., Vandermarken, T., Denison, M. S., Elskens, M., Baeyens, W., & Gao, Y. (2019). In situ measurement of estrogenic activity in various aquatic systems using organic diffusive gradients in thin-film coupled with ERE-CALUX bioassay. Environment international, 127, 13-20.
  • Vandermarken, T., Croes, K., Van Langenhove, K., Boonen, I., Servais, P., Garcia-Armisen, T., ... & Elskens, M. (2018). Endocrine activity in an urban river system and the biodegradation of estrogen-like endocrine disrupting chemicals through a bio-analytical approach using DRE-and ERE-CALUX bioassays. Chemosphere, 201, 540-549.
  • Croes, K., Van den Heuvel, R., Van den Bril, B., Staelens, J., Denison, M. S., Van Langenhove, K., ... & Elskens, M. (2016). Assessment of estrogenic and androgenic activity in PM10 air samples from an urban, industrial and rural area in Flanders (Belgium) using the CALUX bioassay. Environmental research, 150, 66-72.
  • Van Langenhove, K., Croes, K., Denison, M. S., Elskens, M., & Baeyens, W. (2011). The CALUX bio-assay: analytical comparison between mouse hepatoma cell lines with a low (H1L6. 1c3) and high (H1L7. 5c1) number of dioxin response elements. Talanta, 85(4), 2039-2046.
  • Elskens, M., Baston, D. S., Stumpf, C., Haedrich, J., Keupers, I., Croes, K., ... & Goeyens, L. (2011). CALUX measurements: Statistical inferences for the dose–response curve. Talanta, 85(4), 1966-1973.
  • Vandermarken, T., Boonen, I., Gryspeirt, C., Croes, K., Van Den Houwe, K., Denison, M. S., ... & Elskens, M. (2019). Assessment of estrogenic compounds in paperboard for dry food packaging with the ERE-CALUX bioassay. Chemosphere, 221, 99-106.
  • Vandermarken, T., De Galan, S., Croes, K., Van Langenhove, K., Vercammen, J., Sanctorum, H., ... & Baeyens, W. (2016). Characterisation and implementation of the ERE-CALUX bioassay on indoor dust samples of kindergartens to assess estrogenic potencies. The Journal of steroid biochemistry and molecular biology, 155, 182-189.
Associated documents

Contact person

Imke Boonen

Organisations

Vrije Universiteit Brussel
Analytical Environmental and Geo-chemistry
Belgium
Brussels Region