A non-canonical adenosinergic pathway led by CD38 in human melanoma cells induces suppression of T cell proliferation

作者：Morandi Fabio^*; Morandi Barbara; Horenstein Alberto L; Chillemi Antonella; Quarona Valeria; Zaccarello Gianluca; Carrega Paolo; Ferlazzo Guido; Mingari Maria Cristina; Moretta Lorenzo; Pistoia Vito; Malavasi Fabio

来源：Oncotarget, 2015, 6(28): 25602-25618.

DOI：10.18632/oncotarget.4693

• Melanoma
• ectoenzymes
• adenosine
• immunosuppression

Nucleotide-metabolizing ectoenzymes are endowed with an extracellular catalytic domain, which is involved in regulating the extracellular nucleotide/nucleoside balance. The tumor microenvironment contains high levels of adenosine (ADO) generated by this enzymatic network, thus promoting tumor growth by inhibiting anti-tumor immune responses. ADO inhibition in melanoma murine models limits tumor metastases and restores anti-tumor immune responses.
This work investigates the expression and function of ectoenzymes in primary human melanoma cell lines. All of latter cells expressed CD38, CD39, CD73, and CD203a/PC-1, and produced ADO from AMP and NAD(+). Melanoma cells inhibited T cell proliferation through an ADO-dependent mechanism, since such inhibition was reverted using CD38/CD73 specific inhibitors.
Melanoma cells abolished the function of effector memory, central memory and reduced naive CD4(+) T cell proliferation. Accordingly, phosphorylation of S6 ribosomal protein, p38 and Stat1 was lower in activated memory cells than in naive CD4(+) T lymphocytes. Melanoma cells also inhibited proliferation of naive, memory and -to a lesser extent-of effector CD8(+) T cells. These different inhibitory effects correlated with distinct patterns of expression of the ADO receptor A2a and A2b. These results show that primary human melanoma cell lines suppress in vitro T cell proliferation through an adenosinergic pathway in which CD38 and CD73 play a prominent role.

• 出版日期2015-9-22