Related Experiment Video
Updated: Jun 9, 2026
09:36
Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 16, 2010
Mammary carcinogen-protein binding potentials: novel and biologically relevant structure-activity relationship model
A R Cunningham1, S Qamar, C A Carrasquer
1James Graham Brown Cancer Center, University of Louisville, KY, USA. al.cunningham@louisville.edu
SAR and QSAR in Environmental Research
|September 7, 2010
Summary
This study introduces novel carcinogen prediction models using biological descriptors like ligand-receptor interactions, improving accuracy over traditional chemical descriptors for rat mammary carcinogens.
Area of Science:
- Toxicology
- Computational Chemistry
- Molecular Biology
Background:
- Structure-activity relationship (SAR) models for carcinogenesis traditionally rely on chemical descriptors.
- A gap exists in understanding the link between chemical structure and carcinogenic activity via biological targets.
Purpose of the Study:
- To develop and validate new SAR models for rat mammary carcinogens using biological descriptors.
- To investigate ligand-receptor interactions as predictors of carcinogenic potential.
- To enhance the predictivity of carcinogenicity models by incorporating biological insights.
Main Methods:
- Utilized the cat-SAR expert system to develop models based on biological descriptors (ligand-receptor interactions).
- Performed virtual screening of carcinogens, non-carcinogens, and mammary carcinogens against 5494 target proteins.
- Employed leave-one-out and external validation techniques for model assessment.
- Developed hybrid fragment-ligand models to improve predictive accuracy.
Main Results:
- Ligand-based models achieved 71% (carcinogen-non-carcinogen) and 72% (carcinogen-non-mammary carcinogen) concordance.
- Hybrid fragment-ligand models significantly improved concordance to 85% and 83% in internal validation.
- External validation of hybrid models showed concordances of 81% and 76%.
- Identified biologically relevant protein targets for known rat mammary carcinogens (PhIP, atrazine, indomethacin).
Conclusions:
- Biological descriptors, specifically ligand-receptor interactions, offer enhanced predictivity for carcinogenicity compared to chemical descriptors.
- The cat-SAR system with biological descriptors provides a valuable tool for understanding carcinogen mechanisms.
- This approach bridges the gap between chemical structure and carcinogenic activity by focusing on molecular targets.
- The developed models show promise for improving risk assessment and drug development by identifying potential carcinogens.
Related Concept Videos
01:25Mutagenicity and Carcinogenicity
Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...
01:28Structure-Activity Relationships and Drug Design
Drug design is a dynamic field that involves discovering and developing new medications based on specific biological targets. This process heavily relies on structure-activity relationships (SAR) and quantitative structure-activity relationships (QSAR) to guide the design and optimization of efficient drugs.
SAR studies the intricate relationship between a drug's chemical structure and biological activity. It focuses on understanding how modifications to a drug's structure can influence its...
SAR studies the intricate relationship between a drug's chemical structure and biological activity. It focuses on understanding how modifications to a drug's structure can influence its...
01:25Bioactivation and Tissue Toxicity
Bioactivation is a metabolic process that transforms less reactive substances into highly reactive metabolites, initiating tissue toxicity. This transformation can lead to various toxic effects, including carcinogenesis and teratogenesis. Reactive metabolites are classified into two main types: electrophiles and free radicals.Electrophiles are electron-deficient species and are produced primarily by the enzyme cytochrome P-450 during the metabolism of compounds containing carbon, nitrogen, or...
01:24Protein Organization
Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
The primary structure of a protein is its amino acid sequence.
02:40Ligand Binding Sites
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
00:49Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...