Reoxygenation from chronic hypoxia promotes metastatic processes in pancreatic cancer through the Hedgehog signaling.
Bottom Line: A Hedgehog (Hh) signaling component, Gli1, was significantly increased by reoxygenation.Gli1 knockdown inhibited reoxygenation-induced increases in proliferation and tumorigenicity and decreased invasiveness through suppression of matrix metalloproteinase (MMP) 2 and MMP9.These results suggest that metastatic processes in PDAC are induced through activation of the Hh signaling pathway.
Affiliation: Department of Cancer Therapy and Research, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.Show MeSH
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Mentions: Next, the correlation between activation of Hh signaling and reoxygenation-induced proliferation and invasiveness was investigated. Transfection with Gli1 siRNA in reoxygenated Ch-H-R cells led to an 80–90% decrease in Gli1 mRNA expression (Fig. S10). Gli1 siRNA-transfected reoxygenated cells showed significant decreases in anchorage-dependent proliferation and invasion (Fig.3a,b). To investigate the effect of MMP on invasiveness, MMP siRNA was used. MMP2 and MMP9 knockdown efficiencies were approximately 70–90 and 60–80%, respectively (Fig. S11). The invasiveness of MMP2 and MMP9 siRNA-transfected reoxygenated Ch-H-R cells was significantly lower than that of the control cells (Fig.3c). MMP2 and MMP9 co-knockdown significantly inhibited invasion compared with MMP2 or MMP9 knockdown alone (Fig.3c). In addition, Gli1 knockdown significantly decreased the expression of MMP2 and MMP9 (Fig.3d). Next, to investigate whether the upregulation of Gli1 was through Hh signaling, Shh and Smo knockdown experiments were performed. Shh and Smo knockdown efficiencies were over 90% (Fig. S12). Shh siRNA and Smo siRNA transfected-reoxygenated Ch-H-R cells showed lower anchorage-dependent proliferative (Fig.4a,b) and invasive (Fig.4c,d) abilities than the control in both cell lines. These results suggest that enhanced cell proliferation and invasion by reoxygenation are induced through the activation of Hh signaling.
Affiliation: Department of Cancer Therapy and Research, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.