XXII. BIOCHEMICKÝ ZJAZD - Jesseniova lekárska fakulta

Lectures
HIGH affINITY carBOHYDraTE aND NON-carBOHYDraTE LIGaNDS
for LECTIN-TYPE aCTIvaTION rECEPTOrs of naTUral KILLEr CELLS
rEGULaTE effECTOr fUNCTION THrOUGH PI3K paTHWay, aND
GENEraTE PErmaNENT IMMUNE prOTECTION agaINST MELaNOMas
Veronika Benson 1 , Valeria Grobárová, 1 Katarína Hulíková 1 Jan Svoboda 1 ,
Daniel Rozbeský 1,2 , Daniel Kavan 1,2 , Alan Kádek 1,2 , Karel Křenek 1 , Anna Fišerová 1 ,
Vladimír Křen 1 and Karel Bezouška 1,2
1
Institute of Microbiology v.v.i., Academy of Sciences of Czech Republic and
2
Department of Biochemistry, Faculty of Science, Charles University Prague, Praha,
Czech Republic
Our laboratories are interested in understanding of complex interactions between activation
receptors of natural killer (NK) cells, their target structures at tumor cell surface, and
intracellular activation pathways resulting in the activation of NK cell effector functions at
molecular and cellular level. To identify high afinity ligands, we produce stable recombinant
soluble forms of NK cell receptors such as NKR-P1, CD69, and NKG2D and use them
in binding, inhibition and precipitation studies based on standard biochemical assays and
oligosaccharide arrays. High affinity ligand mimetics are constructed by attachment of the
active compounds to polyamidoamine or calix arene cores, or by dimerization of the ligand
through a defined chemical linker. GlcNAc-coated polyamidoamine dendrimers induce
upregulation of antibody formation that triggered by their interaction with mNKR-P1C.
GlcNAc-coated calyx arene downregulated the expression of GlcNAc transferases MGAT3
and MGAT 5, increased the susceptibility of tumor cells to natural killing, and increased
the expression of mNKG2D through the activation of PI3K–ERK but not phospholipase C-γ-
JNK pathway. GlcNAc dimers can provide permanent protection in 70 % of mice bearing
syngeneic B16S melanomas. This is due to activation of NKT lymphocytes, and subsequent
infiltration of tumors by CD8 + cytotoxic lymphocytes. The exceptional signaling efficiency
of GlcNAc dimers is explaned by sequential cooperative engagement of mNKR-P1A leading
to the formation of large signaling complexes of about 20 MDa containing G proteins, ß-
arrestin, phosphorylated dynamin, Src kinase, Vav, Rac1, Grb2, and Ras. Use of combined
ligand mimetics results in engagement of several target receptors, and efficient activation
of NK cell effector functions due to effective receptor cross-talk.
Supported by grants by Ministry of Education of Czech Republic (MSM_21620808
and 1M0505), by the Institutional Research Concept for the Institute of Microbiology
(AVOZ50200510), by Czech Science Foundation (303/09/0477 and 305/09/H008), Grant
Agency of Academy of Sciences of the Czech Republic nebo (ASCR) IAA500200620, and by
the European Commission (Project Spine 2 Complexes, contract LSHG-CT-2006-031220).
XXII. Biochemistry Congress, Martin
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