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Activation of expression of hedgehog target genes in basal cell carcinomas

J M Bonifas1, S Pennypacker, P T Chuang

  • 1Department of Dermatology, San Francisco General Hospital, California, USA.

The Journal of Investigative Dermatology
|May 12, 2001
PubMed

Insights

Mutations in hedgehog pathway genes drive basal cell carcinoma. Gene expression analysis reveals altered mRNA levels in tumors, suggesting stem cell-like properties and complex signaling effects.

Area of Science:

  • Oncology
  • Molecular Biology
  • Dermatology

Background:

  • Mutations in hedgehog signaling pathway genes, particularly Patched 1 (PTC1) and Smoothened (SMO), are critical drivers of basal cell carcinoma (BCC) development.
  • Understanding gene expression in BCC is crucial for elucidating how hedgehog pathway abnormalities lead to aberrant tumor cell behavior and for studying human in vivo hedgehog target gene control.

Purpose of the Study:

  • To investigate and compare gene expression profiles in basal cell carcinomas versus normal skin.
  • To identify specific genes and pathways affected by hedgehog signaling abnormalities in BCC.
  • To explore the phenotypic characteristics of BCC tumor cells in relation to epidermal stem cells.

Main Methods:

  • Quantitative analysis of messenger RNA (mRNA) levels for various genes, including hedgehog pathway components (PTC1, SMO, GLI1, GLI2), WNT family members (WNT2B, WNT5a, WNT4, WNT7B), and other relevant genes (HIP, c-MYC, c-FOS, BMP2, BMP4).
  • Comparison of gene expression data between tumor samples (basal cell carcinomas) and control samples (normal skin).

Main Results:

  • Basal cell carcinomas exhibited significantly increased mRNA levels for PTC1, GLI1, HIP, WNT2B, and WNT5a compared to normal skin.
  • Decreased mRNA levels were observed for c-MYC, c-FOS, and WNT4 in BCCs relative to normal skin.
  • mRNA levels for PTC2, GLI2, WNT7B, and BMP2/4 remained unchanged between BCCs and normal skin.

Conclusions:

  • The observed gene expression changes in BCCs suggest that hedgehog signaling pathway mutations can have both direct (cell autonomous) and indirect effects on tumor development.
  • The distinct gene expression signature in BCCs indicates a cellular phenotype that shares similarities with epidermal stem cells.
  • These findings provide insights into the molecular mechanisms underlying BCC pathogenesis and potential therapeutic targets.

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