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Published on: August 23, 2024

XAF1 mediates apoptosis through an extracellular signal-regulated kinase pathway in colon cancer

Li Fen Yu1, Jide Wang, Bing Zou

  • 1Department of Gastroenterology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.

Cancer
|March 27, 2007
PubMed
Abstract

Insights

XIAP-associated factor 1 (XAF1) expression increases apoptosis in colon cancer by regulating the ERK1/2 pathway. Inhibiting this pathway transcriptionally upregulates XAF1, mediating cancer cell death.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Signaling

Background:

  • XIAP-associated factor 1 (XAF1) antagonizes the antiapoptotic X-linked inhibitor of apoptosis protein (XIAP).
  • The extracellular signal-regulated kinase (ERK) pathway promotes cell proliferation and survival.
  • The interplay between XAF1 and ERK signaling in colon cancer remains to be fully elucidated.

Purpose of the Study:

  • To investigate the correlation between the ERK1/2 signaling pathway and XAF1 in colon cancer.
  • To determine how modulating ERK1/2 activity affects XAF1 and XIAP expression.
  • To assess the role of XAF1 in ERK1/2-mediated apoptosis and proliferation in colon cancer cells.

Main Methods:

  • Utilized four human colon cancer cell lines (HCT1116, Lovo, DLD1, SW1116).
  • Manipulated ERK1/2 signaling using dominant-negative MEK1 (DN-MEK1) and the MEK inhibitor U0126.
  • Quantified XAF1 and XIAP protein levels, XAF1 promoter activity, cell proliferation (MTT assay), and apoptosis (Hoechst staining).

Main Results:

  • Inhibition of ERK1/2 signaling (U0126, DN-MEK1) upregulated XAF1 expression and XAF1 promoter activity in a time- and dose-dependent manner.
  • Conversely, XIAP expression was downregulated upon ERK1/2 inhibition.
  • Overexpression of XAF1 enhanced apoptosis, while XAF1 knockdown reversed the anti-proliferative effects of ERK1/2 inhibition.

Conclusions:

  • ERK1/2 pathway inhibition upregulates XAF1 expression via transcriptional regulation, requiring de novo protein synthesis.
  • XAF1 mediates apoptosis induced by the inhibition of the ERK1/2 pathway in colon cancer.
  • These findings highlight a novel regulatory axis involving XAF1 and ERK1/2 in colon cancer progression and therapeutic targeting.

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