The Dual Role of TGF-β and Hypoxia on MMP14-Mediated Invasion in PC3 Cells

The MMP14 gene, which encodes the only membrane-bound collagenase, is highly expressed in malignant tumors and plays a decisive role in invasiveness. This study investigated the transcriptional regulation of MMP14 by the TGF-β cytokine and hypoxia in PC3 prostate carcinoma cells. Bioinformatic analysis confirmed the presence of key regulatory elements in the MMP14 promoter, specifically the HRE (for HIF-1α) and SMAD binding sites. Three 5' deletion fragments of the MMP14 promoter (P1: -1251/+75; P2: -649/+75; P3: -176/+75) were cloned for functional analysis. PC3 cells were treated with TGF-β, the hypoxia-mimetic CoCl₂, and the combination. Gene and protein expression were analyzed using Real-Time PCR and Immunofluorescence Cytochemistry (IFC), respectively, while promoter activities were assessed via a Luciferase reporter assay. COL1A expression was also evaluated to explore its association with MMP14-mediated extracellular matrix remodeling. Hypoxia emerged as the dominant inductive factor. MMP14 mRNA and protein levels were significantly elevated under hypoxic and combined TGF-β/CoCl₂ conditions. Promoter analysis revealed that the full-length P1 construct was consistently upregulated by all treatments. However, the shorter P2 and P3 fragments exhibited a decrease in activity with TGF-β alone, suggesting a complex, region-specific regulation predominantly influenced by hypoxic signaling. Critically, COL1A1 mRNA expression was observed in hypoxic groups with elevated MMP14 levels, indicating a possible inverse relationship between MMP14 induction and COL1A-associated extracellular matrix remodeling. Hypoxia is the primary driver of MMP14 induction and protein accumulation in PC3 cells, with TGF-β acting as a complex co-regulator whose activating effect is potentiated under low-oxygen stress. These findings highlight the contribution of the HIF/MMP14 axis to invasion-associated molecular regulation in prostate cancer.