Macrophages and CD8(+) T cells mediate the antitumor efficacy of combined CD40 ligation and imatinib therapy in gastrointestinal stromal tumors Journal Article


Authors: Zhang, J. Q.; Zeng, S.; Vitiello, G. A.; Seifert, A. M.; Medina, B. D.; Beckman, M. J.; Loo, J. K.; Santamaria-Barria, J.; Maltbaek, J. H.; Param, N. J.; Moral, J. A.; Zhao, J. N.; Balachandran, V.; Rossi, F.; Antonescu, C. R.; DeMatteo, R. P.
Article Title: Macrophages and CD8(+) T cells mediate the antitumor efficacy of combined CD40 ligation and imatinib therapy in gastrointestinal stromal tumors
Abstract: Tyrosine kinase inhibition of gastrointestinal stromal tumors (GIST) is effective but typically culminates in resistance and is rarely curative. Immunotherapy has potential application to GIST, as we previously showed that T-cell checkpoint blockade increases the antitumor effects of imatinib. Here, we showed that ligation of CD40 using an agonistic antibody (anti-CD40) activated tumor-associated macrophages (TAMs) in vivo in a knock-in mouse model of GIST harboring a germ-line mutation in Kit exon 11. Activated TAMs had greater TNFa production and NFkB signaling and directly inhibited tumor cells in vitro. Anti-CD40 required concomitant therapy with imatinib for efficacy and depended on TAMs, and to a lesser extent CD8þ T cells, but not on CD4þ T cells or B cells. In an analysis of 50 human GIST specimens by flow cytometry, we found that CD40 was expressed on human TAMs and tumor cells yet was downregulated after response to imatinib. CD40 ligation did not have a direct inhibitory effect on human GIST cells. Our findings provide the rationale for combining anti-CD40 and tyrosine kinase inhibition to treat human GIST. © 2018 American Association for Cancer Research.
Journal Title: Cancer Immunology Research
Volume: 6
Issue: 4
ISSN: 2326-6066
Publisher: American Association for Cancer Research  
Date Published: 2018-04-01
Start Page: 434
End Page: 447
Language: English
DOI: 10.1158/2326-6066.cir-17-0345
PROVIDER: scopus
PUBMED: 29467128
DOI/URL:
Notes: Article -- Export Date: 2 July 2018 -- Source: Scopus
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