[Correlation between Gli1 expression and clinicopathological significance in human pancreatic cancer]

To study the clinicopathological significance and relationship of Gli1, MDM2 and p53 expression in human pancreatic cancer.

The expression of Gli1, MDM2 and p53 proteins in 57 paired paraffin embedded pancreatic ductal adenocarcinoma (PDAC) specimens and adjacent non-cancerous pancreatic tissues was detected by immunohistochemistry. The relationship between their expression and clinicopathological characters was analyzed. Quantitative real-time PCR (qRT-PCR) was used to examine the expression of Gli1 mRNA level in 14 paired fresh PDAC specimens and adjacent non-cancerous pancreatic tissues. siRNA interference were used to further detect the close relationship among them.

IHC showed the expression of Gli1 (50.9%), MDM2 (57.9%) and p53 (56.1%) was increased in 57 cases of pancreatic cancer compared to that in paired normal pancreatic tissues (33.3%, 26.3% and 17.5% respectively, t = 2.413, 2.848 and 2.960, all P < 0.05). Gli1 expression was positively associated with tumor TNM stage (χ(2) = 8.211, P = 0.004), invasion depth (χ(2) = 4.247, P = 0.039) and MDM2 expression (r = 0.299, χ(2) = 5.105, P = 0.024), while expression of MDM2 and p53 was associated with tumor invasion depth (χ(2) = 5.182, P = 0.023) and TNM stage (χ(2) = 5.696, P = 0.017), respectively. Univariate and multivariate analysis revealed that Gli1 was an independent adverse prognostic indicator for patients with PDAC (RR = 2.290, 95%CI: 1.051-4.992, P = 0.037), and patients with Gli1 and MDM2 co-expression had a significantly poorer overall survival than patients with their negative expression (P = 0.034). Gli1 mRNA expression was much higher in 14 cases of PDAC than that in adjacent normal pancreatic tissues (t = 2.926, P = 0.012). In p53 mutant AsPC-1 cells, Gli1 knockdown down regulated MDM2, but had no effect on p53 expression, whereas Gli1 knockdown down regulated MDM2 and up regulated p53 protein levels in p53 wild-type Capan-2 cells.

Gli1, MDM2 and p53 are overexpressed in PDAC, and are benefit for predicting patients' prognosis. Gli1can regulate MDM2 and wild-type p53 expression. Their co-expression might coordinately contribute to the development and progression of PDAC.