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Retinoic acid synergizes with cyclic AMP to enhance MMP-2 basal promoter activity
1Discovery Research, Takarazuka Research Institute, Novartis Pharma K. K., 10-66 Miyuki-cho, Takarazuka, 665-8666, Japan.
Abstract:
Matrix metalloproteinase-2 (MMP-2) degrades basement membrane collagen and its abnormal expression is associated with the enhanced malignancy of metastasizing cancer cells. Retinoids and cyclic AMP analogs have been shown to affect MMP-2 production. Here we demonstrate that the expression of the human MMP-2 gene is enhanced by a synergistic action of retinoic acid (RA) and dibutyryl cyclic AMP (Bt2cAMP). RA also synergizes with Bt2cAMP in enhancing the basal promoter activity when the MMP-2 proximal promoter activity is induced by transient transfection and RA/Bt2cAMP treatment in human fibrosarcoma HT1080 cells. Deletions beyond -315 bp from the transcription initiation site drastically reduce the synergistic enhancement. A search for a cis-element in the MMP-2 proximal promoter shows the presence of a CRE-like sequence (TGACGTCCC) at position -292 bp in the opposite strand. The CRE-like sequence makes complexes with two DNA binding proteins. The results demonstrate that the RA/Bt2cAMP-enhanced transcription of the MMP-2 gene is dependent on the general transcription machinery and suggest that the basal promoter may be a potential target for gene-specific activators.
Insights
Retinoic acid (RA) and dibutyryl cyclic AMP (Bt2cAMP) synergistically enhance matrix metalloproteinase-2 (MMP-2) gene expression. This synergistic action involves a CRE-like sequence in the MMP-2 promoter, crucial for increased cancer cell malignancy.
Area of Science:
- Molecular Biology
- Cancer Research
- Gene Regulation
Background:
- Matrix metalloproteinase-2 (MMP-2) plays a critical role in degrading the basement membrane, facilitating cancer cell metastasis.
- Abnormal MMP-2 expression is linked to increased malignancy in metastasizing cancers.
- Retinoids and cyclic AMP analogs are known modulators of MMP-2 production.
Purpose of the Study:
- To investigate the synergistic effect of retinoic acid (RA) and dibutyryl cyclic AMP (Bt2cAMP) on human MMP-2 gene expression.
- To identify the specific promoter regions and cis-elements involved in this synergistic transcriptional enhancement.
- To elucidate the mechanism by which RA and Bt2cAMP co-regulate MMP-2 transcription.
Main Methods:
- Transient transfection assays using human fibrosarcoma HT1080 cells.
- Reporter gene assays with deletions in the MMP-2 proximal promoter.
- Analysis of DNA-protein interactions at a CRE-like sequence within the MMP-2 promoter.
Main Results:
- RA and Bt2cAMP exhibit a synergistic action in enhancing human MMP-2 gene expression.
- Synergistic enhancement of MMP-2 promoter activity is observed, particularly with deletions beyond -315 bp.
- A CRE-like sequence (TGACGTCCC) at -292 bp in the MMP-2 promoter binds two DNA-binding proteins.
- The RA/Bt2cAMP-enhanced transcription is dependent on the general transcription machinery.
Conclusions:
- The synergistic action of RA and Bt2cAMP significantly enhances MMP-2 gene transcription.
- The MMP-2 basal promoter, specifically a CRE-like element, is a key target for these synergistic activators.
- These findings suggest potential therapeutic strategies targeting MMP-2 for controlling cancer metastasis.