A potent mitogenic lectin from the mycelia of a phytopathogenic fungus, Rhizoctonia bataticola, with complex sugar specificity and cytotoxic effect on human ovarian cancer cells.

Abstract

A lectin with strong mitogenic activity towards human peripheral blood mononuclear cells (PBMCs) and cytotoxic effect on human ovarian cancer cells has been purified from the mycelium of a phytopathogenic fungus, Rhizoctonia bataticola, using ion exchange chromatography and affinity chromatography on asialofetuin-Sepharose. The lectin, termed RBL, is a tetramer of 11-kDa subunits and has unique amino acid sequence at its blocked N-terminus. The purified RBL was blood group nonspecific and its hemagglutination activity was inhibited by mucin (porcine stomach), fetuin (fetal calf serum) and asialofetuin. Glycan array analysis revealed high affinity binding of RBL towards N-glycans and also the glycoproteins containing complex N-glycan chains. Interestingly, the lectin showed high affinity for glycans which are part of ovarian cancer marker CA125, a high molecular weight mucin containing high mannose and complex bisecting type N-linked glycans as well core 1 and 2 type O-glycans. RBL bound to human PBMCs eliciting strong mitogenic response, which could be blocked by mucin, fetuin and asialofetuin demonstrating the carbohydrate-mediated interaction with the cells. Analysis of the kinetics of binding of RBL to PBMCs revealed a delayed mitogenic response indicating a different signaling pathway compared to phytohemagglutinin-L. RBL had a significant cytotoxic effect on human ovarian cancer cell line, PA-1.

• Authors: Nagaraja N Nagre, Vishwanath B Chachadi, Palaniswamy M Sundaram, Ramachandra S Naik, Radha Pujari, Padma Shastry, Bale M Swamy, Shashikala R Inamdar
• Journal: Glycoconjugate journal (Glycoconj J) Vol. 27 Issue 3 Pg. 375-86 (Apr 2010) ISSN: 1573-4986 [Electronic] United States
• PMID: 20306342 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Glycoproteins
• Lectins
• Polysaccharides

Topics

• Animals
• Cell Line
• Cell Line, Tumor
• Cell Survival (drug effects)
• Chromatography, Gel
• Electrophoresis, Polyacrylamide Gel
• Female
• Flow Cytometry
• Fungi (chemistry)
• Glycoproteins (metabolism)
• Hemagglutination Tests
• Humans
• Hydrogen-Ion Concentration
• Lectins (chemistry, isolation & purification, metabolism, pharmacology)
• Molecular Weight
• Mycelium (chemistry)
• Ovarian Neoplasms (metabolism)
• Polysaccharides (metabolism)
• Protein Binding
• Rabbits