Dysregulation of gap junction intercellular communication (GJIC) is recognized as one of the key hallmarks for identifying non-genotoxic carcinogens (NGTxC). Currently, there is a demand for in vitro assays addressing the gap junction hallmark, which would have the potential to eventually become an integral part of an integrated approach to the testing and assessment (IATA) of NGTxC. The scrape loading-dye transfer (SL-DT) technique is a simple assay for the functional evaluation of GJIC in various in vitro cultured mammalian cells and represents an interesting candidate assay. Out of the various techniques for evaluating GJIC, the SL-DT assay has been used frequently to assess the effects of various chemicals on GJIC in toxicological and tumor promotion research. In this review, we systematically searched the existing literature to gather papers assessing GJIC using the SL-DT assay in a rat liver epithelial cell line, WB-F344, after treating with chemicals, especially environmental and food toxicants, drugs, reproductive-, cardio- and neuro-toxicants and chemical tumor promoters. We discuss findings derived from the SL-DT assay with the known knowledge about the tumor-promoting activity and carcinogenicity of the assessed chemicals to evaluate the predictive capacity of the SL-DT assay in terms of its sensitivity, specificity and accuracy for identifying carcinogens. These data represent important information with respect to the applicability of the SL-DT assay for the testing of NGTxC within the IATA framework.
- Keywords
- carcinogenesis, carcinogens, gap junction intercellular communication, scrape loading-dye transfer,
- MeSH
- Coloring Agents metabolism MeSH
- Biological Assay methods MeSH
- Cell Line MeSH
- Microscopy, Fluorescence methods MeSH
- Liver pathology MeSH
- Carcinogens MeSH
- Rats MeSH
- Cells, Cultured MeSH
- Gap Junctions metabolism MeSH
- Cell Communication drug effects physiology MeSH
- Carcinogenicity Tests methods MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Names of Substances
- Coloring Agents MeSH
- Carcinogens MeSH
In the last decade, it has become evident that complex mixtures of cyanobacterial bioactive substances, simultaneously present in blooms, often exert adverse effects that are different from those of pure cyanotoxins, and awareness has been raised on the importance of studying complex mixtures and chemical interactions. We aimed to investigate cytotoxic and genotoxic effects of complex extracts from laboratory cultures of cyanobacterial species from different orders (Cylindrospermopsis raciborskii, Aphanizomenon gracile, Microcystis aeruginosa, M. viridis, M. ichtyoblabe, Planktothrix agardhii, Limnothrix redekei) and algae (Desmodesmus quadricauda), and examine possible relationships between the observed effects and toxin and retinoic acid (RA) content in the extracts. The cytotoxic and genotoxic effects of the extracts were studied in the human hepatocellular carcinoma HepG2 cell line, using the MTT assay, and the comet and cytokinesis-block micronucleus (cytome) assays, respectively. Liquid chromatography electrospray ionization mass spectrometry (LC/ESI-MS) was used to detect toxins (microcystins (MC-LR, MC-RR, MC-YR) and cylindrospermopsin) and RAs (ATRA and 9cis-RA) in the extracts. Six out of eight extracts were cytotoxic (0.04-2 mgDM/mL), and five induced DNA strand breaks at non-cytotoxic concentrations (0.2-2 mgDM/mL). The extracts with genotoxic activity also had the highest content of RAs and there was a linear association between RA content and genotoxicity, indicating their possible involvement; however further research is needed to identify and confirm the compounds involved and to elucidate possible genotoxic effects of RAs.
- Keywords
- algae, chemical analysis, complex mixtures, cyanobacteria, cyanotoxins, cytotoxicity, extracts, genotoxicity, microcystins, retinoic acids,
- MeSH
- Alkaloids isolation & purification toxicity MeSH
- Hep G2 Cells MeSH
- Chlorophyta metabolism MeSH
- Chromatography, Liquid MeSH
- Spectrometry, Mass, Electrospray Ionization MeSH
- Comet Assay MeSH
- Humans MeSH
- Microcystins isolation & purification toxicity MeSH
- Micronucleus Tests MeSH
- Micronuclei, Chromosome-Defective chemically induced MeSH
- DNA Damage * MeSH
- Cyanobacteria metabolism MeSH
- Tandem Mass Spectrometry MeSH
- Cyanobacteria Toxins MeSH
- Tretinoin isolation & purification toxicity MeSH
- Cell Survival drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Alkaloids MeSH
- cylindrospermopsin MeSH Browser
- microcystin MeSH Browser
- Microcystins MeSH
- Cyanobacteria Toxins MeSH
- Tretinoin MeSH
