Dataset Information

Erk1R84H is an oncoprotein that causes hepatocellular carcinoma in mice and imposes rigorous negative feedback loop on the RTK-Ras-Raf-MEK pathway

ABSTRACT: The extracellular signal-regulated kinases (Erks), Erk1 and Erk2, are crucial components of the receptor tyrosine kinase (RTK)-Ras-Raf-MEK pathway, which is frequently mutated and constitutively activated in various cancers. Despite Erk activity being commonly observed in cancer, the role of direct Erk activation in driving tumorigenesis remains unproven. This study explores the oncogenic potential of intrinsically active Erk1 mutants, particularly Erk1R84H, in both in vivo and in vitro models.We established a transgenic mouse model enabling tissue-specific and temporally controlled expression of Erk1R84H. Upon inducing Erk1R84H expression in the liver, we observed the development of hepatocellular carcinoma (HCC) characterized by increased liver weight, necrosis, and significant loss of body weight. Intriguingly, the phosphorylated/active form of Erk1R84H was dramatically downregulated during HCC development, becoming almost undetectable in mature tumors. This phenomenon was mirrored in NIH3T3 cells transformed by Erk1R84H, where TEY phosphorylation was significantly reduced as transformed foci appeared.Our proteomic and phosphoproteomic analyses of stable clones expressing Erk1R84H or Erk1R84S revealed substantial changes in protein expression and kinase activity. Key findings included the upregulation of CDK1, AURKB, and CDK2, and the downregulation of DNA repair and circadian rhythm-related kinases. Notably, Upp1, a crucial enzyme in nucleotide metabolism, was highly upregulated in clones transformed by Erk1R84S or Erk1R84H, suggesting its role in supporting the transformed phenotype.Furthermore, we demonstrated that the feedback inhibition mechanism suppressing Erk phosphorylation is dependent on Erk activity itself. Inhibition of Erk1R84H or Erk1R84S with Erk inhibitors restored TEY phosphorylation, highlighting the importance of precise rather very low Erk activity in maintaining the transformed state.In summary, Erk1R84H is confirmed as an efficient oncoprotein capable of inducing HCC in vivo and transforming cells in culture. The mechanism it uses for transformation, involving significant down regulation of its own activity underscores the notion that too high oncogenic activity is not favored by the tumor and proposes a modified therapeutic approach of targeting Erk for its activation rather than inhibition.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Spleen, Heart, Liver, Cell Culture, Muscle, Kidney

SUBMITTER: Alon Savidor

LAB HEAD: David Engelberg

PROVIDER: PXD056168 | Pride | 2025-08-04

REPOSITORIES: Pride

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			Action	DRS
	HFX_DE_17338_RH1_DAY1_12122022.raw	Raw
	HFX_DE_17338_RH1_DAY3_12122022.raw	Raw
	HFX_DE_17338_RH2_DAY1_12122022.raw	Raw
	HFX_DE_17338_RH2_DAY3_12122022.raw	Raw
	HFX_DE_17338_RH3_DAY1_12122022.raw	Raw

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Erk1<sup>R84H</sup> is an oncoprotein that causes hepatocellular carcinoma in mice and imposes a rigorous negative feedback loop.

Soudah Nadine N Baskin Alexey A Darash-Yahana Merav M Darlyuk-Saadon Ilona I Smorodinsky-Atias Karina K Shalit Tali T Yu Wei-Ping WP Savidor Alon A Pikarsky Eli E Engelberg David D

Oncogene 20250520 31

The receptor tyrosine kinase (RTK)-Ras-Raf-MEK-Erk cascade is frequently mutated in cancer, but it is not known whether Erk is a sole mediator of the pathway's oncogenicity, and what degree of Erk activity is required for oncogenicity. Also, it is assumed that high Erk activity is required to impose and maintain oncogenicity, but the exact degree of required activity is not clear. We report that induced expression of the intrinsically active variant Erk1<sup>R84H</sup> in mouse liver gave rise t ...[more]

PMID: 40394416

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Project description:The extracellular signal-regulated kinases (Erks), Erk1 and Erk2, are crucial components of the receptor tyrosine kinase (RTK)-Ras-Raf-MEK pathway, which is frequently mutated and constitutively activated in various cancers. Despite Erk activity being commonly observed in cancer, the role of direct Erk activation in driving tumorigenesis remains unproven. This study explores the oncogenic potential of intrinsically active Erk1 mutants, particularly Erk1R84H, in both in vivo and in vitro models. We established a transgenic mouse model enabling tissue-specific and temporally controlled expression of Erk1R84H. Upon inducing Erk1R84H expression in the liver, we observed the development of hepatocellular carcinoma (HCC) characterized by increased liver weight, necrosis, and significant loss of body weight. Intriguingly, the phosphorylated/active form of Erk1R84H was dramatically downregulated during HCC development, becoming almost undetectable in mature tumors. This phenomenon was mirrored in NIH3T3 cells transformed by Erk1R84H, where TEY phosphorylation was significantly reduced as transformed foci appeared. Our proteomic and phosphoproteomic analyses of stable clones expressing Erk1R84H or Erk1R84S revealed substantial changes in protein expression and kinase activity. Key findings included the upregulation of CDK1, AURKB, and CDK2, and the downregulation of DNA repair and circadian rhythm-related kinases. Notably, Upp1, a crucial enzyme in nucleotide metabolism, was highly upregulated in clones transformed by Erk1R84S or Erk1R84H, suggesting its role in supporting the transformed phenotype. Furthermore, we demonstrated that the feedback inhibition mechanism suppressing Erk phosphorylation is dependent on Erk activity itself. Inhibition of Erk1R84H or Erk1R84S with Erk inhibitors restored TEY phosphorylation, highlighting the importance of precise rather very low Erk activity in maintaining the transformed state. In summary, Erk1R84H is confirmed as an efficient oncoprotein capable of inducing HCC in vivo and transforming cells in culture. The mechanism it uses for transformation, involving significant down regulation of its own activity underscores the notion that too high oncogenic activity is not favored by the tumor and proposes a modified therapeutic approach of targeting Erk for its activation rather than inhibition.

Project description:Purpose: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated mortality worldwide. Although the molecular mechanisms underpinning HCC are unknown, gene copy number and associated mRNA expression changes are frequently reported. Experimental Design: Comparative genomic hybridization arrays spotted with 4,041 bacterial artificial chromosome clones were used to assess copy number changes in 45 HCC tissues to identify chromosomal regions associated with the pathogenesis of HCC. Seventy more HCC tissues were used to validate candidate genes by using western blots and immunohistochemistry. Results: A total of 259 clones were associated with copy number changes that significantly differed between normal liver and HCC samples. The chromosomal region 1q32.1 containing the nuclear casein kinase and cyclin-dependent kinase substrate 1 (NUCKS1) gene was associated with tumor vascular invasion. Western blot analysis demonstrated that NUCKS1 was up-regulated in 37 of 70 (52.8%) HCC tissues compared with adjacent non-tumor tissues, and over-expressed in a vast majority of HCCs (44/52, 84.6%) as determined by immunohistochemical staining. Furthermore, immunostaining of both NUCKS1 and glypican-3 improved the diagnostic prediction of HCC. Knock-down of NUCKS1 by siRNA decreased the cell viability of the Hep3B cell line and reduced tumor formation in a xenograft mouse model. Functional enrichment analysis revealed the association of NUCKS1 with signal transduction, immunity and defense, and nucleotide metabolism pathways. Conclusions: NUCKS1 was identified as a potential oncogene at chromosomal 1q32.1 in patients with HCC, and it might be a valuable immunodiagnostic marker for HCC. Comparative genomic hybridization arrays spotted with 4,041 bacterial artificial chromosome clones were used to assess copy number changes in 45 HCC tissues and 25 normal liver tissues to identify chromosomal regions associated with the pathogenesis of HCC

Dataset Information

Erk1R84H is an oncoprotein that causes hepatocellular carcinoma in mice and imposes rigorous negative feedback loop on the RTK-Ras-Raf-MEK pathway

Dataset's files

Publications

Erk1<sup>R84H</sup> is an oncoprotein that causes hepatocellular carcinoma in mice and imposes a rigorous negative feedback loop.

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Dataset Information

Erk1R84H is an oncoprotein that causes hepatocellular carcinoma in mice and imposes rigorous negative feedback loop on the RTK-Ras-Raf-MEK pathway

Dataset's files

Publications

Erk1&lt;sup&gt;R84H&lt;/sup&gt; is an oncoprotein that causes hepatocellular carcinoma in mice and imposes a rigorous negative feedback loop.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Erk1<sup>R84H</sup> is an oncoprotein that causes hepatocellular carcinoma in mice and imposes a rigorous negative feedback loop.