TY - JOUR
T1 - Cooperation of adenosine and prostaglandin E2 (PGE2) in amplification of cAMP-PKA signaling and immunosuppression
AU - Su, Yunyun
AU - Huang, Xiaojun
AU - Raskovalova, Tatiana
AU - Zacharia, Lefteris
AU - Lokshin, Anna
AU - Jackson, Edwin
AU - Gorelik, Elieser
PY - 2008/11
Y1 - 2008/11
N2 - Introduction: We hypothesize that adenosine and PGE2 could have a complementary immunosuppressive effect that is mediated via common cAMP-PKA signaling. Materials and methods: To test this hypothesis, the effect of adenosine and PGE2 on the cytotoxic activity and cytokine production of lymphokine activated killer (LAK) cells was investigated. Results: PGE 2 and adenosine inhibited LAK cells cytotoxic activity and production of INF-γ, GM-CSF and TNF-α. In combination they showed substantially higher inhibition than each modality used alone. Using agonists and antagonists specific for PGE2 and adenosine receptors we found that cooperation of PGE2 and adenosine in their inhibitory effects are mediated via EP2 and A2A receptors, respectively. LAK cells have 35-fold higher expression of EP2 than A2A. Combined PGE2 and adenosine treatment resulted in augmentation of cAMP production, PKA activity, CREB phosphorylation and inhibition of Akt phosphorylation. Wortmannin and LY294002 enhanced the suppressive effects of adenosine and PGE2. In contrast, Rp-8-Br-cAMPS, an inhibitor of PKA type I blocked their immunosuppressive effects, suggesting that the inhibitory effects of PGE2 and adenosine are mediated via common pathway with activation of cAMP-PKA and inhibition of Akt. Conclusion: In comparison to other immunosuppressive molecules (TGF-β and IL-10), adenosine and PGE 2 are unique in their ability to inhibit the executive function of highly cytotoxic cells. High intratumor levels of adenosine and PGE2 could protect tumor from immune-mediated destruction by inactivation of the tumor infiltrating functionally active immune cells.
AB - Introduction: We hypothesize that adenosine and PGE2 could have a complementary immunosuppressive effect that is mediated via common cAMP-PKA signaling. Materials and methods: To test this hypothesis, the effect of adenosine and PGE2 on the cytotoxic activity and cytokine production of lymphokine activated killer (LAK) cells was investigated. Results: PGE 2 and adenosine inhibited LAK cells cytotoxic activity and production of INF-γ, GM-CSF and TNF-α. In combination they showed substantially higher inhibition than each modality used alone. Using agonists and antagonists specific for PGE2 and adenosine receptors we found that cooperation of PGE2 and adenosine in their inhibitory effects are mediated via EP2 and A2A receptors, respectively. LAK cells have 35-fold higher expression of EP2 than A2A. Combined PGE2 and adenosine treatment resulted in augmentation of cAMP production, PKA activity, CREB phosphorylation and inhibition of Akt phosphorylation. Wortmannin and LY294002 enhanced the suppressive effects of adenosine and PGE2. In contrast, Rp-8-Br-cAMPS, an inhibitor of PKA type I blocked their immunosuppressive effects, suggesting that the inhibitory effects of PGE2 and adenosine are mediated via common pathway with activation of cAMP-PKA and inhibition of Akt. Conclusion: In comparison to other immunosuppressive molecules (TGF-β and IL-10), adenosine and PGE 2 are unique in their ability to inhibit the executive function of highly cytotoxic cells. High intratumor levels of adenosine and PGE2 could protect tumor from immune-mediated destruction by inactivation of the tumor infiltrating functionally active immune cells.
KW - Adenosine
KW - Cytokine production
KW - Cytotoxicity
KW - Immunosuppression
KW - PGE
UR - http://www.scopus.com/inward/record.url?scp=50649108394&partnerID=8YFLogxK
U2 - 10.1007/s00262-008-0494-5
DO - 10.1007/s00262-008-0494-5
M3 - Article
C2 - 18327580
AN - SCOPUS:50649108394
SN - 0340-7004
VL - 57
SP - 1611
EP - 1623
JO - Cancer Immunology, Immunotherapy
JF - Cancer Immunology, Immunotherapy
IS - 11
ER -