Neutrophil extracellular traps induced by chemotherapy inhibit tumor growth in murine models of colorectal cancer
Yamu Li, … , David Bajor, Zhenghe Wang
Yamu Li, … , David Bajor, Zhenghe Wang
Published January 9, 2024
Citation Information: J Clin Invest. 2024;134(5):e175031. https://doi.org/10.1172/JCI175031.
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Research Article Oncology

Neutrophil extracellular traps induced by chemotherapy inhibit tumor growth in murine models of colorectal cancer

Abstract

Neutrophil extracellular traps (NETs), a web-like structure of cytosolic and granule proteins assembled on decondensed chromatin, kill pathogens and cause tissue damage in diseases. Whether NETs can kill cancer cells is unexplored. Here, we report that a combination of glutaminase inhibitor CB-839 and 5-FU inhibited the growth of PIK3CA-mutant colorectal cancers (CRCs) in xenograft, syngeneic, and genetically engineered mouse models in part through NETs. Disruption of NETs by either DNase I treatment or depletion of neutrophils in CRCs attenuated the efficacy of the drug combination. Moreover, NETs were present in tumor biopsies from patients treated with the drug combination in a phase II clinical trial. Increased NET levels in tumors were associated with longer progression-free survival. Mechanistically, the drug combination induced the expression of IL-8 preferentially in PIK3CA-mutant CRCs to attract neutrophils into the tumors. Further, the drug combination increased the levels of ROS in neutrophils, thereby inducing NETs. Cathepsin G (CTSG), a serine protease localized in NETs, entered CRC cells through the RAGE cell surface protein. The internalized CTSG cleaved 14-3-3 proteins, released BAX, and triggered apoptosis in CRC cells. Thus, our studies illuminate a previously unrecognized mechanism by which chemotherapy-induced NETs kill cancer cells.

Authors

Yamu Li, Sulin Wu, Yiqing Zhao, Trang Dinh, Dongxu Jiang, J. Eva Selfridge, George Myers, Yuxiang Wang, Xuan Zhao, Suzanne Tomchuck, George Dubyak, Richard T. Lee, Bassam Estfan, Marc Shapiro, Suneel Kamath, Amr Mohamed, Stanley Ching-Cheng Huang, Alex Y. Huang, Ronald Conlon, Smitha Krishnamurthi, Jennifer Eads, Joseph E. Willis, Alok A. Khorana, David Bajor, Zhenghe Wang

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Figure 1

The combination of CB-839 and 5-FU induces NETs in xenograft tumors in nude mice.

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The combination of CB-839 and 5-FU induces NETs in xenograft tumors in n...
(A and B) Xenograft tumors of HCT116 were treated with the indicated drugs 5 days on and 2 days off in nude and NSG mice simultaneously, with the growth curves shown in (A) nude mice and (B) NSG mice (5 mice/group). (C and D) Mice were implanted with HCT116 cells, and after 6 days, mice were injected with either 100 μL liposome control or clodronate twice a week (C), IgG control or anti-GM1 twice a week (D), growth curves shown in C for macrophage depletion and D for NK cell depletion (5 mice/group). Mice were treated CB-839, 5-FU, and the drug combination daily continuously. (E–G) CRC xenograft tumors were treated with vehicle (veh) or drug combination (comb) with or without Ly6g antibody injection, tumor sizes were measured, and growth curves are shown in E for HCT116, F for DLD1, and G for RKO (5 mice/group). (H–L) Tumors shown in A and B were stained with antibodies against MPO, which marks neutrophils and NETs, and H3cit, which marks NETs. Representative images are shown in H. Scale bar: 50 μm, and quantifications are shown in I–L (n = 15/group). (M–P) Tumors treated with the indicated drugs were stained with antibodies against MPO or H3cit and quantified (n = 15/group). The growth curves of the drug treatment were published in Zhao et al. (10). Data in (A–G) are plotted as mean + SEM. 2-way ANOVA (A–G) or 1-way ANOVA (I–P) was used for statistical analysis. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.