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Tumour suppressor p16(INK4a) - anoikis-favouring decrease in N/O-glycan/cell surface sialylation by down-regulation

Maho Amano1, Hanna Eriksson, Joachim C Manning

  • 1Field of Drug Discovery Research, Graduate School of Life Sciences, Hokkaido University, Sapporo, Japan. shin@sci.hokudai.ac.jp

The FEBS Journal
|September 5, 2012
PubMed

Insights

Tumour suppressor p16(INK4a) regulates cell anoikis by modulating sialylation and galectin-1 expression. This study reveals that p16(INK4a) impacts sialic acid biosynthesis, affecting cell anoikis in pancreatic cancer.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Cancer Research

Background:

  • Tumour suppressor p16(INK4a) controls cell cycle via cyclin-dependent kinases.
  • Emerging evidence suggests p16(INK4a) influences N/O-glycosylation and galectin expression, impacting anoikis.
  • Anoikis, a form of programmed cell death, is crucial in preventing cancer progression.

Purpose of the Study:

  • To investigate the role of p16(INK4a) in modulating N/O-glycosylation and galectin expression to induce anoikis in pancreatic cancer cells.
  • To elucidate the mechanisms by which p16(INK4a) affects sialylation pathways and cell anoikis.
  • To identify key enzymes in sialic acid biosynthesis regulated by p16(INK4a).

Main Methods:

  • Utilized chemoselective N/O-glycan enrichment technology (glycoblotting) for glycan analysis.
  • Employed genetic and metabolic engineering, including transfection and medium supplementation, to manipulate sialylation.
  • Applied cytofluorometric analysis of lectin binding and quantitative mass spectrometry (MS) for protein and enzyme quantification.

Main Results:

  • Confirmed a significant decrease in sialylation and identified limited substrate availability for α2,6-sialylation.
  • Observed enhanced galectin-1 presence and altered glycosyltransferase expression, including p16(INK4a)-dependent down-regulation of sialic acid biosynthesis enzymes (GNE, N-acetylneuraminic acid 9-phosphate synthase).
  • Demonstrated that partial restoration of sialylation in GNE-transfected cells reduced anoikis, supporting the role of sialic acid availability.

Conclusions:

  • p16(INK4a) modulates cell reactivity to galectin-1 by regulating sialic acid biosynthesis pathway enzymes, in addition to altering α2,6-sialyltransferase expression.
  • This highlights a novel mechanism for controlling anoikis in pancreatic carcinoma cells.
  • Findings provide insights into the complex interplay between p16(INK4a), glycosylation, and cancer cell fate.

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