Related Experiment Video
Updated: Mar 7, 2026
Spatial and Temporal Control of Murine Melanoma Initiation from Mutant Melanocyte Stem Cells
Published on: June 7, 2019
Heat shock antagonizes UVA-induced responses in murine melanocytes and melanoma cells: an unexpected interaction
Leonardo Vinícius Monteiro de Assis1, Maria Nathália Moraes, Ana Maria de Lauro Castrucci
1Laboratory of Comparative Physiology of Pigmentation, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil. amdlcast@ib.usp.br.
Abstract:
The skin is under the influence of oscillatory factors such as light and temperature. This organ possesses a local system that controls several aspects in a time-dependent manner; moreover, the skin has a well-known set of opsins whose function is still unknown. We demonstrate that heat shock reduces Opn2 expression in normal Melan-a melanocytes, while the opposite effect is found in malignant B16-F10 cells. In both cell lines, UVA radiation increases the expression of Opn4 and melanin content. Clock genes and Xpa, a DNA repair gene, of malignant melanocytes are more responsive to UVA radiation when compared to normal cells. Most UVA-induced effects are antagonized by heat shock, a phenomenon shown for the first time. Based on our data, the heat produced during UV experiments should be carefully monitored since temperature represents, according to our results, an important confounding factor, and therefore it should, when possible, be dissociated from UV radiation. The responses displayed by murine melanoma cells, if proven to also take place in human melanoma, may represent an important step in cancer development and progression.
Insights
Skin cells respond to light and heat. Heat shock affects opsin expression differently in normal versus melanoma cells, and UVA radiation impacts DNA repair genes more in melanoma cells. Temperature is a key factor in UV response studies.
Area of Science:
- Skin biology
- Photobiology
- Melanoma research
Background:
- Skin is influenced by environmental factors like light and temperature.
- Skin possesses local time-dependent control systems and opsins of unknown function.
- Melanocytes, including normal (Melan-a) and malignant (B16-F10) cells, are key players in skin response.
Purpose of the Study:
- To investigate the effects of heat shock and UVA radiation on opsin expression and melanin content in melanocytes.
- To compare the responses of normal and malignant melanocytes to these stimuli.
- To identify the role of temperature as a confounding factor in UV radiation studies.
Main Methods:
- Treatment of Melan-a and B16-F10 cells with heat shock and/or UVA radiation.
- Measurement of Opsin 2 (Opn2) and Opsin 4 (Opn4) expression.
- Assessment of melanin content.
- Analysis of clock genes and Xpa (DNA repair gene) expression.
Main Results:
- Heat shock reduced Opn2 expression in normal melanocytes but increased it in melanoma cells.
- UVA radiation increased Opn4 expression and melanin content in both cell types.
- Malignant melanocytes showed greater responsiveness of clock genes and Xpa to UVA radiation compared to normal cells.
- Heat shock antagonized most UVA-induced effects, indicating temperature as a confounding factor.
Conclusions:
- Temperature significantly influences cellular responses to UVA radiation, acting as a confounding factor that needs careful monitoring and dissociation.
- Differential responses of normal and melanoma cells to heat and UVA suggest potential implications in melanoma development and progression.
- The findings highlight the importance of controlled environmental conditions in skin research and melanoma studies.
Related Concept Videos
02:45Responses to Heat and Cold Stress
01:35Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
01:19Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...