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Published on: September 6, 2024

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Molecular mechanism for SHP2 in promoting HER2-induced signaling and transformation

Xiangdong Zhou1, Yehenew M Agazie

  • 1Department of Biochemistry and The Marry Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia 26506, USA.

The Journal of Biological Chemistry
|March 6, 2009
PubMed

Insights

Src homology phosphotyrosyl phosphatase 2 (SHP2) enhances HER2 signaling in breast cancer by stabilizing Ras. This mechanism involves dephosphorylating HER2, leading to increased cell transformation and suggesting SHP2 as a therapeutic target.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Signaling

Background:

  • HER2 signaling is crucial in breast cancer development and progression.
  • The precise role of Src homology phosphotyrosyl phosphatase 2 (SHP2) in HER2-driven pathways remains unclear.
  • Understanding SHP2's mechanism in HER2 signaling is vital for therapeutic strategies.

Purpose of the Study:

  • To elucidate the mechanism by which SHP2 modulates HER2-induced signaling and cell transformation.
  • To investigate SHP2's role in downstream pathways, including Ras-ERK and PI3K-Akt.
  • To identify potential therapeutic targets for HER2-overexpressing cancers.

Main Methods:

  • Investigated SHP2's effect on Ras-extracellular signal-regulated kinase 1 and 2 (ERK1/2) and phosphoinositide-3-kinase-Akt (PI3K-Akt) pathways.
  • Assessed the impact of SHP2 on the half-life of activated Ras.
  • Analyzed the dephosphorylation of a HER2 autophosphorylation site crucial for Ras GTPase-activating protein (RasGAP) binding.
  • Utilized a HER2 mutant lacking the SHP2 target site to evaluate signaling and transformation potential.

Main Results:

  • SHP2 positively modulates Ras-ERK1/2 and PI3K-Akt pathways downstream of HER2.
  • SHP2 increases the half-life of activated Ras by dephosphorylating a HER2 autophosphorylation site.
  • This dephosphorylation event disrupts RasGAP binding, prolonging GTP-Ras levels and enhancing HER2 signaling.
  • A HER2 mutant lacking the SHP2 target site showed increased signaling and transformation capacity.

Conclusions:

  • SHP2 promotes HER2-induced signaling and cell transformation by dephosphorylating a negative regulatory autophosphorylation site on HER2.
  • This action leads to sustained Ras activation, enhancing downstream signaling.
  • SHP2 represents a potential therapeutic target for breast cancer and other HER2-overexpressing malignancies.

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