Cis-platin responsive sequences in the human c-myc promoter

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• The c-myc gene is a proto-oncogene frequently dysregulated in cancer.
• Understanding the regulatory elements of c-myc is critical for developing targeted cancer therapies.
• Cisplatin is a widely used platinum-based chemotherapy agent.

Purpose of the Study:

• To investigate the effect of cisplatin on the expression of the c-myc gene.
• To identify specific DNA sequences within the c-myc promoter that mediate the response to cisplatin.

Main Methods:

• Transfection of rat fibroblasts with recombinant plasmids containing c-myc promoter sequences linked to reporter genes (chloramphenicol acetyl-transferase - cat).
• Generation of stable transfectant cell lines.
• Treatment of cell lines with cisplatin and measurement of cat gene expression.

Main Results:

• Cisplatin (5 x 10(-5) M) significantly stimulated cat gene expression (9- and 11-fold) in cell lines with c-myc promoter constructs truncated at -2319 and -350, respectively.
• A cell line with a c-myc/cat construct truncated at -290 showed no response to cisplatin.
• These results pinpoint a cisplatin-responsive element located between -290 and -350 on the c-myc promoter.

Conclusions:

• A specific DNA region within the c-myc promoter, between coordinates -290 and -350, contains a cisplatin-responsive element.
• This element plays a role in regulating c-myc gene expression in response to cisplatin treatment.
• The findings contribute to understanding the molecular mechanisms of cisplatin action and may inform future therapeutic strategies.