Insulin receptor substrate-1 deficiency drives a proinflammatory phenotype in KRAS mutant lung adenocarcinoma

Heather E Metz1, Julia Kargl2, Stephanie E Busch3

  • 1Department of Medicine, Fred Hutchinson Cancer Research Center, Seattle, WA 98109; Department of Pathology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109; Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109;

Insights

Insulin receptor substrate-1 (IRS-1) deficiency surprisingly worsens lung cancer survival by promoting inflammation via JAK/STAT signaling. Inhibiting this pathway reduced tumor growth, especially in IRS-1-deficient tumors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Signaling

Background:

  • Insulin receptor substrate-1 (IRS-1) is a key signaling adaptor in cancer.
  • IRS-1 is typically thought to promote tumor growth via PI3K signaling.
  • Its role in lung cancer, particularly KRAS-mutant adenocarcinoma, requires further investigation.

Purpose of the Study:

  • To investigate the role of IRS-1 in lung cancer progression and survival.
  • To elucidate the molecular mechanisms by which IRS-1 influences tumor growth.
  • To evaluate the therapeutic potential of targeting IRS-1-associated pathways.

Main Methods:

  • Analysis of human lung adenocarcinoma tissue microarrays for IRS-1 expression and survival correlation.
  • Generation and analysis of genetically engineered mouse models (Kras/Irs-1(-/-)) to study IRS-1 deficiency in vivo.
  • Investigating downstream signaling pathways, including JAK/STAT, in response to IRS-1 loss.
  • Pharmacological inhibition of JAK/STAT signaling in mouse models.

Main Results:

  • Reduced IRS-1 staining in human lung tumors correlated with decreased patient survival, particularly in KRAS-mutant cases.
  • Kras/Irs-1(-/-) mice exhibited increased tumor burden and mortality.
  • IRS-1 deficiency enhanced JAK/STAT signaling through the IL-22 receptor, promoting inflammation.
  • JAK inhibitor treatment significantly reduced tumor burden in both wild-type and IRS-1-deficient mice, with a more pronounced effect in the latter.

Conclusions:

  • Contrary to expectations, IRS-1 loss exacerbates lung cancer progression and mortality.
  • IRS-1 deficiency promotes tumor growth by activating pro-inflammatory JAK/STAT signaling.
  • Targeting the JAK/STAT pathway represents a promising therapeutic strategy for lung cancer, especially in IRS-1-deficient contexts.

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