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Glycosylation status of vitamin D binding protein in cancer patients

Douglas S Rehder1, Randall W Nelson, Chad R Borges

  • 1The Biodesign Institute at Arizona State University, Tempe, 85287, USA.

Protein Science : a Publication of the Protein Society
|July 31, 2009
PubMed

Insights

Previous studies suggested cancer patients lack glycosylated vitamin D binding protein (DBP), impacting Gc macrophage activating factor (GcMAF). This study found no significant difference in DBP glycosylation between cancer patients and healthy controls, challenging prior hypotheses.

Area of Science:

  • Biochemistry
  • Immunology
  • Oncology

Background:

  • Previous research indicated vitamin D binding protein (DBP) deglycosylation in cancer patients.
  • This deglycosylation was thought to eliminate the precursor for Gc macrophage activating factor (GcMAF).
  • GcMAF is crucial for immune response and is a product of DBP glycosidase activity.

Purpose of the Study:

  • To directly measure the O-linked trisaccharide glycosylation of serum DBP in cancer patients.
  • To compare DBP glycosylation levels between patients with breast, colorectal, pancreatic, and prostate cancer and healthy individuals.

Main Methods:

  • Utilized an electrospray ionization-based mass spectrometric immunoassay.
  • Analyzed serum-derived DBP from 56 cancer patients and healthy controls.

Main Results:

  • No significant depletion of DBP trisaccharide glycosylation was observed in cancer patients compared to controls.
  • The degree of glycosylation in serum DBP was consistent across the examined cancer types.

Conclusions:

  • The hypothesis that DBP deglycosylation explains reduced GcMAF precursor in cancer patients is not supported by these findings.
  • Alternative explanations for the altered immune activity in cancer patients must be explored.
  • Further research is needed to understand the true origins of GcMAF and its role in cancer immunology.

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