Targeted phosphoproteomics of the Ras signaling network reveal regulatory mechanisms mediated by oncogenic KRAS

Tlsty, Thea D.; Yuan, Tina L.; Trinidad, Marena I.; Morris, John H.; Afghani, Shervin; Oses-Prieto, Juan; Ritchie, Cayde; Zahari, Muhammad Saddiq; Benes, Cyril H.; Burlingame, Alma L.; McCormick, Frank

doi:10.1101/695460

Cited by 2 publications

(4 citation statements)

References 81 publications

(77 reference statements)

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“…Mass spectrometry studies revealed that peptide fragments of DNMT1 phosphorylated at S714 were enriched in vehicle treated cells when compared to HMBA-treated cells. Regulation of the phosphorylation of DNMT1 at S714 by RAS and SET were reported in a recent publication and in a preprint ( 31 , 32 ). Using HPRD v.9, we identified other possible kinases that can phosphorylate DNMT1 at S714, and among the highest scoring kinases were GSK3 and Cyclin Dependent Kinase 1 (CDK1).…”

Section: Resultsmentioning

confidence: 86%

“…We identified a DNMT1 phosphorylation site on S714, which is part of the 62-amino acid-long autoinhibitory linker (693-754) that functions to occlude DNA from the active site of DNMT1 to prevent the methylation of unmethylated DNA ( 17 ). While previous phosphoproteomic analysis revealed phosphorylation of S714 of DNMT that resulted in altered expression of DNMT1 target genes ( 32 ), the basis for the regulation of DNMT1 activity and consequences were not well-defined. We hypothesized that the phosphorylation at S714 might be involved in the catalytic function of DNMT1 due to its close proximity with the cysteine rich CXXC domain, which is reported to be involved in DNMT1 enzymatic activity by sensing hemimethylated DNA and establishing contacts with DNA ( 18 ).…”

Section: Discussionmentioning

confidence: 94%

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Re-Expression of ERα and AR in Receptor Negative Endocrine Cancers via GSK3 Inhibition

et al. 2022

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DNA methylation, catalyzed by DNA methyltransferase (DNMT), is a well-characterized epigenetic modification in cancer cells. In particular, promoter hypermethylation of AR and ESR1 results in loss of expression on Androgen Receptor (AR) and Estrogen Receptor (ER), respectively, and is associated with a hormone refractory state. We now report that Glycogen Synthase Kinase 3 (GSK3) phosphorylates DNMT1 at S714, which is localized to a 62 amino acid region referred to as auto-inhibitory linker, which functions to occlude the DNA from the active site of DNMT1 to prevent the methylation of unmethylated DNA. Molecular Dynamics simulation indicates that phosphorylation at S714 resulted in conformational rearrangement of the autoinhibitory domain that inactivated its ability to block the methylation of unmethylated DNA and resulted in enhanced DNA binding. Treatment with a novel and more selective inhibitor of GSK3 resulted in decreased methylation of the promoter region of genes encoding the Androgen Receptor (AR) and Estrogen Receptor alpha (ERa) and re-expression of the AR and ERa in AR negative prostate cancer and ER negative breast cancer cells, respectively. As a result, concurrent treatment with the GSK3 inhibitor resulted in responsiveness of AR negative prostate cancer and ER negative breast cancer cells to inhibitors of the AR or ER, respectively, in in vitro and in vivo experimental models.

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Section: Resultsmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 94%

Re-Expression of ERα and AR in Receptor Negative Endocrine Cancers via GSK3 Inhibition

et al. 2022

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“…Of note, increased phosphorylation of serine 62 of MYC is indicative of the activation of this multifunctional oncoprotein, which cooperates with HER2 to stimulate cell proliferation 24 , 25 . Increased phosphorylation of MAP2K2 (MEK2) at threonine 394 and MAPK1 (ERK2) at threonine 185 was observed without statistical significance or tendency, which might be associated with inhibition of negative feedback of RAS/ERK signaling, resulting in HER2 (Y1248) downregulation 26 , 27 . These results suggest that the ErbB signaling is activated in HER2-positive gastric cancer compared with HER2-negative gastric cancer.…”

Section: Resultsmentioning

confidence: 98%

“…Decreased levels of these phosphosites are associated with inactivation of the corresponding oncoproteins 29 – 36 . In addition, the decreased phosphorylation of MAP2K2 (MEK2) at threonine 394 and MAPK1 (ERK2) at threonine 185 might be explained by the inhibition of the ErbB signaling by drug therapy 26 , 27 . HER2 (S1054) and MYC (T58) tended to be upregulated in the post-treatment HER2-positive T group.…”

Section: Resultsmentioning

confidence: 99%

Temporal dynamics from phosphoproteomics using endoscopic biopsy specimens provides new therapeutic targets in stage IV gastric cancer

Hirano

Abe

Nojima

et al. 2022

Sci Rep

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Phosphoproteomic analysis expands our understanding of cancer biology. However, the feasibility of phosphoproteomic analysis using endoscopically collected tumor samples, especially with regards to dynamic changes upon drug treatment, remains unknown in stage IV gastric cancer. Here, we conducted a phosphoproteomic analysis using paired endoscopic biopsy specimens of pre- and post-treatment tumors (Ts) and non-tumor adjacent tissues (NATs) obtained from 4 HER2-positive gastric cancer patients who received trastuzumab-based treatment and from pre-treatment Ts and NATs of 4 HER2-negative gastric cancer patients. Our analysis identified 14,622 class 1 phosphosites with 12,749 quantified phosphosites and revealed molecular changes by HER2 positivity and treatment. An inhibitory signature of the ErbB signaling was observed in the post-treatment HER2-positive T group compared with the pre-treatment HER2-positive T group. Phosphoproteomic profiles obtained by a case-by-case review using paired pre- and post-treatment HER2-positive T could be utilized to discover predictive or resistant biomarkers. Furthermore, these data nominated therapeutic kinase targets which were exclusively activated in the patient unresponded to the treatment. The present study suggests that a phosphoproteomic analysis of endoscopic biopsy specimens provides information on dynamic molecular changes which can individually characterize biologic features upon drug treatment and identify therapeutic targets in stage IV gastric cancer.

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Targeted phosphoproteomics of the Ras signaling network reveal regulatory mechanisms mediated by oncogenic KRAS

Abstract: Background

Cited by 2 publications

References 81 publications

Re-Expression of ERα and AR in Receptor Negative Endocrine Cancers via GSK3 Inhibition

Re-Expression of ERα and AR in Receptor Negative Endocrine Cancers via GSK3 Inhibition

Temporal dynamics from phosphoproteomics using endoscopic biopsy specimens provides new therapeutic targets in stage IV gastric cancer

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