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The acinar differentiation determinant PTF1A inhibits initiation of pancreatic ductal adenocarcinoma.

Krah NM, De La O JP, Swift GH, Hoang CQ, Willet SG, Chen Pan F, Cash GM, Bronner MP, Wright CV, MacDonald RJ, Murtaugh LC - Elife (2015)

Bottom Line: Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile.As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC.Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Genetics, University of Utah, Salt Lake City, United States.

ABSTRACT
Understanding the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) may provide therapeutic strategies for this deadly disease. Recently, we and others made the surprising finding that PDAC and its preinvasive precursors, pancreatic intraepithelial neoplasia (PanIN), arise via reprogramming of mature acinar cells. We therefore hypothesized that the master regulator of acinar differentiation, PTF1A, could play a central role in suppressing PDAC initiation. In this study, we demonstrate that PTF1A expression is lost in both mouse and human PanINs, and that this downregulation is functionally imperative in mice for acinar reprogramming by oncogenic KRAS. Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile. As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC. Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.

No MeSH data available.


Related in: MedlinePlus

Ptf1aCreERT deletion efficiency following tamoxifen treatment.6–8-week-old mice of indicated genotypes were administered according to low- or high-dose regimens (1 × 0.17 mg/g or 0.25 mg/g, respectively), and pancreata were harvested 2 weeks (A–E) or 3 days (F–J) after the last dose. (A–D) Immunofluorescence for amylase (red) and the Cre reporter R26REYFP (green) on pancreata from low-TM treated mice of the indicated genotypes. For Ptf1a cKO; KrasG12D pancreata, efforts were made to find histologically normal areas to provide an accurate quantification of Cre-mediated recombination. (E) The proportion of EYFP expression among amylase+ acinar cells was quantified for all genotypes. No significant difference was noted between any groups (n = 3–6 per genotype). (F–H) Immunofluorescence for PTF1A (red), the Cre reporter EYFP (green), and DAPI (blue) in Ptf1aCreERT/lox; KrasG12D; R26REYFP/+ mice 3 days after no TM administration (A), low dose TM (B), or high dose TM (C). (I) Quantification of the percentage of EYFP+ (green) and Ptf1a+ (red) pancreatic cells in each indicated treatment group 3 days after final TM administration (n = 3 per group). (J) Quantification of total EYFP+ acinar cells that no longer express Ptf1a (green) or retain Ptf1a protein expression (red) 3 days following low and high TM treatment (n = 3 per group). Scale bars: (A–D) 100 μm, (F–H) 50 μm.DOI:http://dx.doi.org/10.7554/eLife.07125.008
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fig2s2: Ptf1aCreERT deletion efficiency following tamoxifen treatment.6–8-week-old mice of indicated genotypes were administered according to low- or high-dose regimens (1 × 0.17 mg/g or 0.25 mg/g, respectively), and pancreata were harvested 2 weeks (A–E) or 3 days (F–J) after the last dose. (A–D) Immunofluorescence for amylase (red) and the Cre reporter R26REYFP (green) on pancreata from low-TM treated mice of the indicated genotypes. For Ptf1a cKO; KrasG12D pancreata, efforts were made to find histologically normal areas to provide an accurate quantification of Cre-mediated recombination. (E) The proportion of EYFP expression among amylase+ acinar cells was quantified for all genotypes. No significant difference was noted between any groups (n = 3–6 per genotype). (F–H) Immunofluorescence for PTF1A (red), the Cre reporter EYFP (green), and DAPI (blue) in Ptf1aCreERT/lox; KrasG12D; R26REYFP/+ mice 3 days after no TM administration (A), low dose TM (B), or high dose TM (C). (I) Quantification of the percentage of EYFP+ (green) and Ptf1a+ (red) pancreatic cells in each indicated treatment group 3 days after final TM administration (n = 3 per group). (J) Quantification of total EYFP+ acinar cells that no longer express Ptf1a (green) or retain Ptf1a protein expression (red) 3 days following low and high TM treatment (n = 3 per group). Scale bars: (A–D) 100 μm, (F–H) 50 μm.DOI:http://dx.doi.org/10.7554/eLife.07125.008

Mentions: Given the severity and robustness of PanIN formation in Ptf1a cKO; KrasG12D mice 9 months after TM administration, we next determined if loss of Ptf1a had a more acute effect on acinar cell transformation. To address this issue, 6- to 8-week-old mice were administered TM (0.17 mg/g) and pancreata were harvested 2 or 6 weeks thereafter (Figure 3A). To ensure that Cre-mediated recombination rates were comparable between genotypes, we determined the percentage of acinar cells expressing the R26REYFP reporter at 2 weeks post-TM administration. We found similar acinar recombination rates of 21–25% between genotypes (Figure 2—figure supplement 1). As the efficiency of Cre-mediated recombination can vary between different target loci (Liu et al., 2013), we additionally compared the extent and distribution of PTF1A ablation to that of R26REYFP activation. 3 days after TM administration (0.17 mg/g), there was a ∼20% decrease in the number of PTF1A+ cells detected by immunofluorescence (Figure 2—figure supplement 2). Importantly, the majority (∼75%) of EYFP+ cells were PTF1A-negative at this dose of TM (Figure 2—figure supplement 2), indicating that activation of EYFP provides an approximate surrogate for deletion of Ptf1a.10.7554/eLife.07125.009Figure 3.Loss of Ptf1a is a rate-limiting step in PanIN initiation.


The acinar differentiation determinant PTF1A inhibits initiation of pancreatic ductal adenocarcinoma.

Krah NM, De La O JP, Swift GH, Hoang CQ, Willet SG, Chen Pan F, Cash GM, Bronner MP, Wright CV, MacDonald RJ, Murtaugh LC - Elife (2015)

Ptf1aCreERT deletion efficiency following tamoxifen treatment.6–8-week-old mice of indicated genotypes were administered according to low- or high-dose regimens (1 × 0.17 mg/g or 0.25 mg/g, respectively), and pancreata were harvested 2 weeks (A–E) or 3 days (F–J) after the last dose. (A–D) Immunofluorescence for amylase (red) and the Cre reporter R26REYFP (green) on pancreata from low-TM treated mice of the indicated genotypes. For Ptf1a cKO; KrasG12D pancreata, efforts were made to find histologically normal areas to provide an accurate quantification of Cre-mediated recombination. (E) The proportion of EYFP expression among amylase+ acinar cells was quantified for all genotypes. No significant difference was noted between any groups (n = 3–6 per genotype). (F–H) Immunofluorescence for PTF1A (red), the Cre reporter EYFP (green), and DAPI (blue) in Ptf1aCreERT/lox; KrasG12D; R26REYFP/+ mice 3 days after no TM administration (A), low dose TM (B), or high dose TM (C). (I) Quantification of the percentage of EYFP+ (green) and Ptf1a+ (red) pancreatic cells in each indicated treatment group 3 days after final TM administration (n = 3 per group). (J) Quantification of total EYFP+ acinar cells that no longer express Ptf1a (green) or retain Ptf1a protein expression (red) 3 days following low and high TM treatment (n = 3 per group). Scale bars: (A–D) 100 μm, (F–H) 50 μm.DOI:http://dx.doi.org/10.7554/eLife.07125.008
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fig2s2: Ptf1aCreERT deletion efficiency following tamoxifen treatment.6–8-week-old mice of indicated genotypes were administered according to low- or high-dose regimens (1 × 0.17 mg/g or 0.25 mg/g, respectively), and pancreata were harvested 2 weeks (A–E) or 3 days (F–J) after the last dose. (A–D) Immunofluorescence for amylase (red) and the Cre reporter R26REYFP (green) on pancreata from low-TM treated mice of the indicated genotypes. For Ptf1a cKO; KrasG12D pancreata, efforts were made to find histologically normal areas to provide an accurate quantification of Cre-mediated recombination. (E) The proportion of EYFP expression among amylase+ acinar cells was quantified for all genotypes. No significant difference was noted between any groups (n = 3–6 per genotype). (F–H) Immunofluorescence for PTF1A (red), the Cre reporter EYFP (green), and DAPI (blue) in Ptf1aCreERT/lox; KrasG12D; R26REYFP/+ mice 3 days after no TM administration (A), low dose TM (B), or high dose TM (C). (I) Quantification of the percentage of EYFP+ (green) and Ptf1a+ (red) pancreatic cells in each indicated treatment group 3 days after final TM administration (n = 3 per group). (J) Quantification of total EYFP+ acinar cells that no longer express Ptf1a (green) or retain Ptf1a protein expression (red) 3 days following low and high TM treatment (n = 3 per group). Scale bars: (A–D) 100 μm, (F–H) 50 μm.DOI:http://dx.doi.org/10.7554/eLife.07125.008
Mentions: Given the severity and robustness of PanIN formation in Ptf1a cKO; KrasG12D mice 9 months after TM administration, we next determined if loss of Ptf1a had a more acute effect on acinar cell transformation. To address this issue, 6- to 8-week-old mice were administered TM (0.17 mg/g) and pancreata were harvested 2 or 6 weeks thereafter (Figure 3A). To ensure that Cre-mediated recombination rates were comparable between genotypes, we determined the percentage of acinar cells expressing the R26REYFP reporter at 2 weeks post-TM administration. We found similar acinar recombination rates of 21–25% between genotypes (Figure 2—figure supplement 1). As the efficiency of Cre-mediated recombination can vary between different target loci (Liu et al., 2013), we additionally compared the extent and distribution of PTF1A ablation to that of R26REYFP activation. 3 days after TM administration (0.17 mg/g), there was a ∼20% decrease in the number of PTF1A+ cells detected by immunofluorescence (Figure 2—figure supplement 2). Importantly, the majority (∼75%) of EYFP+ cells were PTF1A-negative at this dose of TM (Figure 2—figure supplement 2), indicating that activation of EYFP provides an approximate surrogate for deletion of Ptf1a.10.7554/eLife.07125.009Figure 3.Loss of Ptf1a is a rate-limiting step in PanIN initiation.

Bottom Line: Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile.As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC.Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Genetics, University of Utah, Salt Lake City, United States.

ABSTRACT
Understanding the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) may provide therapeutic strategies for this deadly disease. Recently, we and others made the surprising finding that PDAC and its preinvasive precursors, pancreatic intraepithelial neoplasia (PanIN), arise via reprogramming of mature acinar cells. We therefore hypothesized that the master regulator of acinar differentiation, PTF1A, could play a central role in suppressing PDAC initiation. In this study, we demonstrate that PTF1A expression is lost in both mouse and human PanINs, and that this downregulation is functionally imperative in mice for acinar reprogramming by oncogenic KRAS. Loss of Ptf1a alone is sufficient to induce acinar-to-ductal metaplasia, potentiate inflammation, and induce a KRAS-permissive, PDAC-like gene expression profile. As a result, Ptf1a-deficient acinar cells are dramatically sensitized to KRAS transformation, and reduced Ptf1a greatly accelerates development of invasive PDAC. Together, these data indicate that cell differentiation regulators constitute a new tumor suppressive mechanism in the pancreas.

No MeSH data available.


Related in: MedlinePlus