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Pivotal Role of the Chromatin Protein Nupr1 in Kras-Induced Senescence and Transformation.

Grasso D, Bintz J, Lomberk G, Molejon MI, Loncle C, Garcia MN, Lopez MB, Urrutia R, Iovanna JL - Sci Rep (2015)

Bottom Line: In the current study, we report that Nupr1 acts as a gene modifier of the effect of Kras(G12D)-induced senescence by regulating Dnmt1 expression and consequently genome-wide levels of DNA methylation.This requirement of Nupr1 expression, however, is not restricted to the pancreas since in lung of Nupr1(-/-) mice the expression of Kras(G12D) induces senescence instead of transformation.Therefore, mechanistically this data reveals that epigenetic events, at least at the level of DNA methylation, modulate the functional outcome of common genetic mutations, such as Kras(G12D), during carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, Marseille, France.

ABSTRACT
Nupr1 is a chromatin protein, which cooperates with Kras(G12D) to induce PanIN formation and pancreatic cancer development in mice, though the molecular mechanisms underlying this effect remain to be fully characterized. In the current study, we report that Nupr1 acts as a gene modifier of the effect of Kras(G12D)-induced senescence by regulating Dnmt1 expression and consequently genome-wide levels of DNA methylation. Congruently, 5-aza-2'-deoxycytydine, a general inhibitor of DNA methylation, reverses the Kras(G12D)-induced PanIN development by promoting senescence. This requirement of Nupr1 expression, however, is not restricted to the pancreas since in lung of Nupr1(-/-) mice the expression of Kras(G12D) induces senescence instead of transformation. Therefore, mechanistically this data reveals that epigenetic events, at least at the level of DNA methylation, modulate the functional outcome of common genetic mutations, such as Kras(G12D), during carcinogenesis. The biomedical relevance of these findings lies in that they support the rational for developing similar therapeutic interventions in human aimed at controlling either the initiation or progression of cancer.

No MeSH data available.


Related in: MedlinePlus

Inhibition of DNA methylation prevents PanINs development.(A) 6 weeks old Nupr1+/+ KrasG12D expressing mice were treated with the inhibitor of DNA methylation 5-aza-dC during three cycles of two weeks as represented by the scheme. Several PanINs lesions were found in pancreas tissue from vehicle-treated animals in contrast to 5-aza-dC-treated animals where almost no lesion was detected. (B) Nupr1+/+ KrasG12D expressing mice were submitted to a cerulein-induced pancreatitis treatment to increases the oncogenic Kras transforming pressure. Compared to vehicle-treated mice, pancreatic from DNA methylation inhibitor-treated animals were resistant to PanINs development with a significant reduction in PanINs development. Means ± SD; **p < 0.01.
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f4: Inhibition of DNA methylation prevents PanINs development.(A) 6 weeks old Nupr1+/+ KrasG12D expressing mice were treated with the inhibitor of DNA methylation 5-aza-dC during three cycles of two weeks as represented by the scheme. Several PanINs lesions were found in pancreas tissue from vehicle-treated animals in contrast to 5-aza-dC-treated animals where almost no lesion was detected. (B) Nupr1+/+ KrasG12D expressing mice were submitted to a cerulein-induced pancreatitis treatment to increases the oncogenic Kras transforming pressure. Compared to vehicle-treated mice, pancreatic from DNA methylation inhibitor-treated animals were resistant to PanINs development with a significant reduction in PanINs development. Means ± SD; **p < 0.01.

Mentions: Based on the fact that inactivation of Nupr1 impairs KrasG12D-associated changes in DNA methylation to establish senescence (oncogene-induced senescence, OIS) through downregulation of Dnmt1, we hypothesized that treatment of KrasG12D expressing Nupr1+/+ animals with inhibitors of DNA methylation should mimic this effect. To explore this concept, we randomized 12 KrasG12D expressing Nupr1+/+ mice into two groups. One of these groups was treated with the DNA methyltransferase inhibitor 5-aza-dC (24 injections of 250 μg/kg of body weight following the protocol described in Fig. 4A) while the control group received vehicle alone. Figure 4 demonstrates that treatment with 5-aza-dC significantly reduces KrasG12D induced development of PanIN lesions (2 ± 1 vs. 27 ± 17 lesions; p < 0.005; n = 6) (Fig. 4A). Moreover, since oncogenic mutations in KRAS cooperate with pancreatitis to give rise to pancreatic cancer with high penetrance, we also investigated whether treatment with 5-aza-dC prevents pancreatitis-enhanced PanIN development. Accordingly, 6 week-old KrasG12D expressing mice, which carry wild type Nupr1 alleles, were treated with either 5-aza-dC or vehicle for 3 weeks. At the end of the first week of 5-aza-dC treatment, mice were also injected with cerulein for 5 days (Fig. 4B). Through these experiments, we found that 5-aza-dC-treated mice were resistant to cerulein-enhanced PanIN induction (3 ± 3 vs. 23 ± 9 lesions in 5-aza-dC and vehicle groups respectively, p < 0.005; n = 6) (Fig. 4B). Thus, pharmacological inhibition of DNA methylation can antagonize the formation of PanINs under both, basal or cerulein-stimulated conditions.


Pivotal Role of the Chromatin Protein Nupr1 in Kras-Induced Senescence and Transformation.

Grasso D, Bintz J, Lomberk G, Molejon MI, Loncle C, Garcia MN, Lopez MB, Urrutia R, Iovanna JL - Sci Rep (2015)

Inhibition of DNA methylation prevents PanINs development.(A) 6 weeks old Nupr1+/+ KrasG12D expressing mice were treated with the inhibitor of DNA methylation 5-aza-dC during three cycles of two weeks as represented by the scheme. Several PanINs lesions were found in pancreas tissue from vehicle-treated animals in contrast to 5-aza-dC-treated animals where almost no lesion was detected. (B) Nupr1+/+ KrasG12D expressing mice were submitted to a cerulein-induced pancreatitis treatment to increases the oncogenic Kras transforming pressure. Compared to vehicle-treated mice, pancreatic from DNA methylation inhibitor-treated animals were resistant to PanINs development with a significant reduction in PanINs development. Means ± SD; **p < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4663475&req=5

f4: Inhibition of DNA methylation prevents PanINs development.(A) 6 weeks old Nupr1+/+ KrasG12D expressing mice were treated with the inhibitor of DNA methylation 5-aza-dC during three cycles of two weeks as represented by the scheme. Several PanINs lesions were found in pancreas tissue from vehicle-treated animals in contrast to 5-aza-dC-treated animals where almost no lesion was detected. (B) Nupr1+/+ KrasG12D expressing mice were submitted to a cerulein-induced pancreatitis treatment to increases the oncogenic Kras transforming pressure. Compared to vehicle-treated mice, pancreatic from DNA methylation inhibitor-treated animals were resistant to PanINs development with a significant reduction in PanINs development. Means ± SD; **p < 0.01.
Mentions: Based on the fact that inactivation of Nupr1 impairs KrasG12D-associated changes in DNA methylation to establish senescence (oncogene-induced senescence, OIS) through downregulation of Dnmt1, we hypothesized that treatment of KrasG12D expressing Nupr1+/+ animals with inhibitors of DNA methylation should mimic this effect. To explore this concept, we randomized 12 KrasG12D expressing Nupr1+/+ mice into two groups. One of these groups was treated with the DNA methyltransferase inhibitor 5-aza-dC (24 injections of 250 μg/kg of body weight following the protocol described in Fig. 4A) while the control group received vehicle alone. Figure 4 demonstrates that treatment with 5-aza-dC significantly reduces KrasG12D induced development of PanIN lesions (2 ± 1 vs. 27 ± 17 lesions; p < 0.005; n = 6) (Fig. 4A). Moreover, since oncogenic mutations in KRAS cooperate with pancreatitis to give rise to pancreatic cancer with high penetrance, we also investigated whether treatment with 5-aza-dC prevents pancreatitis-enhanced PanIN development. Accordingly, 6 week-old KrasG12D expressing mice, which carry wild type Nupr1 alleles, were treated with either 5-aza-dC or vehicle for 3 weeks. At the end of the first week of 5-aza-dC treatment, mice were also injected with cerulein for 5 days (Fig. 4B). Through these experiments, we found that 5-aza-dC-treated mice were resistant to cerulein-enhanced PanIN induction (3 ± 3 vs. 23 ± 9 lesions in 5-aza-dC and vehicle groups respectively, p < 0.005; n = 6) (Fig. 4B). Thus, pharmacological inhibition of DNA methylation can antagonize the formation of PanINs under both, basal or cerulein-stimulated conditions.

Bottom Line: In the current study, we report that Nupr1 acts as a gene modifier of the effect of Kras(G12D)-induced senescence by regulating Dnmt1 expression and consequently genome-wide levels of DNA methylation.This requirement of Nupr1 expression, however, is not restricted to the pancreas since in lung of Nupr1(-/-) mice the expression of Kras(G12D) induces senescence instead of transformation.Therefore, mechanistically this data reveals that epigenetic events, at least at the level of DNA methylation, modulate the functional outcome of common genetic mutations, such as Kras(G12D), during carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, Marseille, France.

ABSTRACT
Nupr1 is a chromatin protein, which cooperates with Kras(G12D) to induce PanIN formation and pancreatic cancer development in mice, though the molecular mechanisms underlying this effect remain to be fully characterized. In the current study, we report that Nupr1 acts as a gene modifier of the effect of Kras(G12D)-induced senescence by regulating Dnmt1 expression and consequently genome-wide levels of DNA methylation. Congruently, 5-aza-2'-deoxycytydine, a general inhibitor of DNA methylation, reverses the Kras(G12D)-induced PanIN development by promoting senescence. This requirement of Nupr1 expression, however, is not restricted to the pancreas since in lung of Nupr1(-/-) mice the expression of Kras(G12D) induces senescence instead of transformation. Therefore, mechanistically this data reveals that epigenetic events, at least at the level of DNA methylation, modulate the functional outcome of common genetic mutations, such as Kras(G12D), during carcinogenesis. The biomedical relevance of these findings lies in that they support the rational for developing similar therapeutic interventions in human aimed at controlling either the initiation or progression of cancer.

No MeSH data available.


Related in: MedlinePlus