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Hypoxia promotes angiogenesis, proliferation, invasion, and metastasis of pancreatic cancer. Essentially, all studies of the hypoxia pathway in pancreatic cancer research to date have focused on fully malignant tumors or cancer cell lines, but the potential role of hypoxia inducible factors (HIF) in the progression of premalignant lesions has not been critically examined. Here, we show that HIF2α is expressed early in pancreatic lesions both in human and in a mouse model of pancreatic cancer. HIF2α is a potent oncogenic stimulus, but its role in Kras-induced pancreatic neoplasia has not been discerned. We used the Ptf1aCre transgene to activate KrasG12D and delete Hif2α solely within the pancreas. Surprisingly, loss of Hif2α in this model led to markedly higher, rather than reduced, number of low-grade pancreatic intraepithelial neoplasia (mPanIN) lesions. These lesions, however, failed to progress to high-grade mPanINs, and displayed exclusive loss of β-catenin and SMAD4. The relationship among HIF2α, β-catenin, and Smad4 was further confirmed in vitro, where silencing of Hif2α resulted in reduced β-catenin and Smad4 transcript levels. Thus, with oncogenic Ras expressed in the pancreas, HIF2α modulates Wnt-signaling during mPanIN progression by maintaining appropriate levels of both Smad4 and β-catenin. Cancer Res; 73(15); 4781–90. ©2013 AACR.

Supplementry Figure 4 - PDF file 812K, HIF2� promotes B-catenin and Smad4 expression

Supplementary Figure 2 - PDF file 2100K, Normal pancreas development in Ptf1Cre;Hif2�f/f mice

Supplementary Figure 5 - PDF file 5613 K, Loss of Smad4 in PKH2 mPanINs

Supplementary Materials and Methods- PDF file 100K, Additional experimental procedures including Generation of Hif2�-floxed mouse line, Tissue processing and Immunostaining, Western Blot, and Small Interfering RNA transfection

Supplementary Figure 1 - PDF file 2170K, Generation of the Hif2�-floxed strain, and validation of Hif2� inactivation in the pancreas

Supplementary Tables S1-S2 - PDF file 73K, List of primary antibodies, along with the sources and working dilutions (S1); primers used in RT-PCR analyses (S2)

Supplementary Figure and Table Legends�- PDF file 93K, Legend for Supplemental Tables S1-S2 and Supplemental Figures S1-S5