Cancer-Associated Fibroblasts Neutralize the Anti-tumor Effect of CSF1 Receptor Blockade by Inducing PMN-MDSC Infiltration of Tumors

Publication date: 13 November 2017
Source:Cancer Cell, Volume 32, Issue 5
Author(s): Vinit Kumar, Laxminarasimha Donthireddy, Douglas Marvel, Thomas Condamine, Fang Wang, Sergio Lavilla-Alonso, Ayumi Hashimoto, Prashanthi Vonteddu, Reeti Behera, Marlee A. Goins, Charles Mulligan, Brian Nam, Neil Hockstein, Fred Denstman, Shanti Shakamuri, David W. Speicher, Ashani T. Weeraratna, Timothy Chao, Robert H. Vonderheide, Lucia R. Languino, Peter Ordentlich, Qin Liu, Xiaowei Xu, Albert Lo, Ellen Puré, Chunsheng Zhang, Andrey Loboda, Manuel A. Sepulveda, Linda A. Snyder, Dmitry I. Gabrilovich
Tumor-associated macrophages (TAM) contribute to all aspects of tumor progression. Use of CSF1R inhibitors to target TAM is therapeutically appealing, but has had very limited anti-tumor effects. Here, we have identified the mechanism that limited the effect of CSF1R targeted therapy. We demonstrated that carcinoma-associated fibroblasts (CAF) are major sources of chemokines that recruit granulocytes to tumors. CSF1 produced by tumor cells caused HDAC2-mediated downregulation of granulocyte-specific chemokine expression in CAF, which limited migration of these cells to tumors. Treatment with CSF1R inhibitors disrupted this crosstalk and triggered a profound increase in granulocyte recruitment to tumors. Combining CSF1R inhibitor with a CXCR2 antagonist blocked granulocyte infiltration of tumors and showed strong anti-tumor effects.

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Kumar et al. show that CSF1R inhibition alters chemokine secretion by cancer-associated fibroblasts, which attracts pro-tumor PMN-MDSCs and results in poor efficacy. Combined inhibition of CSF1R and CXCR2 blocks MDSC recruitment and reduces tumor growth, which is further improved by the addition of anti-PD-1.


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