Abstract
Immunosuppressive myeloid-derived suppressor cells (MDSC) subvert antitumor immunity and limit the efficacy of chimeric antigen receptor T cells (CAR-T). Previously, we reported that the GM-CSF/JAK2/STAT3 axis drives liver-associated MDSC (L-MDSC) proliferation and blockade of this axis rescued antitumor immunity. We extended these findings in our murine liver metastasis (LM) model, by treating tumor-bearing mice with STAT3 inhibitors (STATTIC or BBI608) to further our understanding of how STAT3 drives L-MDSC suppressive function. STAT3 inhibition caused significant reduction of tumor burden as well as L-MDSC frequencies due to decrease in pSTAT3 levels. L-MDSC isolated from STATTIC or BBI608-treated mice had significantly reduced suppressive function. STAT3 inhibition of L-MDSC was associated with enhanced antitumor activity of CAR-T. Further investigation demonstrated activation of apoptotic signaling pathways in L-MDSC following STAT3 inhibition as evidenced by an upregulation of the pro-apoptotic proteins Bax, cleaved caspase-3, and downregulation of the anti-apoptotic protein Bcl-2. Accordingly, there was also a decrease of pro-survival markers, pErk and pAkt, and an increase in pro-death marker, Fas, with activation of downstream JNK and p38 MAPK. These findings represent a previously unrecognized link between STAT3 inhibition and Fas-induced apoptosis of MDSCs. Our findings suggest that inhibiting STAT3 has potential clinical application for enhancing the efficacy of CAR-T cells in LM through modulation of L-MDSC.
This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
The role of myeloid-derived suppressor cells in liver cancer
Discover Oncology Open Access 23 May 2023
-
Evolving cognition of the JAK-STAT signaling pathway: autoimmune disorders and cancer
Signal Transduction and Targeted Therapy Open Access 19 May 2023
-
Regional infusion of a class C TLR9 agonist enhances liver tumor microenvironment reprogramming and MDSC reduction to improve responsiveness to systemic checkpoint inhibition
Cancer Gene Therapy Open Access 14 June 2022
Access options
Subscribe to this journal
Receive 50 print issues and online access
$259.00 per year
only $5.18 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout








References
Guha P, Reha J, Katz SC. Immunosuppression in liver tumors: opening the portal to effective immunotherapy. Cancer Gene Ther. 2017;24:114–20.
Katz SC, Pillarisetty VG, Bleier JI, Kingham TP, Chaudhry UI, Shah AB, et al. Conventional liver CD4 T cells are functionally distinct and suppressed by environmental factors. Hepatology. 2005;42:293–300.
Katz SC, Bamboat ZM, Maker AV, Shia J, Pillarisetty VG, Yopp AC, et al. Regulatory T cell infiltration predicts outcome following resection of colorectal cancer liver metastases. Ann Surg Oncol. 2013;20:946–55.
Katz SC, Pillarisetty V, Bamboat ZM, Shia J, Hedvat C, Gonen M, et al. T cell infiltrate predicts long-term survival following resection of colorectal cancer liver metastases. Ann Surg Oncol. 2009;16:2524–30.
Turcotte S, Katz SC, Shia J, Jarnagin WR, Kingham TP, Allen PJ, et al. Tumor MHC class I expression improves the prognostic value of T-cell density in resected colorectal liver metastases. Cancer Immunol Res. 2014;2:530–7.
Wu AA, Drake V, Huang HS, Chiu S, Zheng L. Reprogramming the tumor microenvironment: tumor-induced immunosuppressive factors paralyze T cells. Oncoimmunology. 2015;4:e1016700.
Yang F, Wei Y, Cai Z, Yu L, Jiang L, Zhang C, et al. Activated cytotoxic lymphocytes promote tumor progression by increasing the ability of 3LL tumor cells to mediate MDSC chemoattraction via Fas signaling. Cell Mol Immunol. 2015;12:66–76.
Pan PY, Wang GX, Yin B, Ozao J, Ku T, Divino CM, et al. Reversion of immune tolerance in advanced malignancy: modulation of myeloid-derived suppressor cell development by blockade of stem-cell factor function. Blood. 2008;111:219–28.
Serafini P, Carbley R, Noonan KA, Tan G, Bronte V, Borrello I. High-dose granulocyte-macrophage colony-stimulating factor-producing vaccines impair the immune response through the recruitment of myeloid suppressor cells. Cancer Res. 2004;64:6337–43.
Sinha P, Clements VK, Fulton AM, Ostrand-Rosenberg S. Prostaglandin E2 promotes tumor progression by inducing myeloid-derived suppressor cells. Cancer Res. 2007;67:4507–13.
Bunt SK, Yang L, Sinha P, Clements VK, Leips J, Ostrand-Rosenberg S. Reduced inflammation in the tumor microenvironment delays the accumulation of myeloid-derived suppressor cells and limits tumor progression. Cancer Res. 2007;67:10019–26.
Gabrilovich D, Ishida T, Oyama T, Ran S, Kravtsov V, Nadaf S, et al. Vascular endothelial growth factor inhibits the development of dendritic cells and dramatically affects the differentiation of multiple hematopoietic lineages in vivo. Blood. 1998;92:4150–66.
Bromberg J. Stat proteins and oncogenesis. J Clin Invest. 2002;109:1139–42.
Nefedova Y, Nagaraj S, Rosenbauer A, Muro-Cacho C, Sebti SM, Gabrilovich DI. Regulation of dendritic cell differentiation and antitumor immune response in cancer by pharmacologic-selective inhibition of the janus-activated kinase 2/signal transducers and activators of transcription 3 pathway. Cancer Res. 2005;65:9525–35.
Thorn M, Guha P, Cunetta M, Espat NJ, Miller G, Junghans RP, et al. Tumor-associated GM-CSF overexpression induces immunoinhibitory molecules via STAT3 in myeloid-suppressor cells infiltrating liver metastases. Cancer Gene Ther. 2016;23:188–98.
Gabrilovich DI, Nagaraj S. Myeloid-derived suppressor cells as regulators of the immune system. Nat Rev Immunol. 2009;9:162–74.
Yu H, Jove R. The STATs of cancer--new molecular targets come of age. Nat Rev Cancer. 2004;4:97–105.
Kortylewski M, Kujawski M, Wang T, Wei S, Zhang S, Pilon-Thomas S, et al. Inhibiting Stat3 signaling in the hematopoietic system elicits multicomponent antitumor immunity. Nat Med. 2005;11:1314–21.
Scholz M, Cinatl J. Fas/FasL interaction: a novel immune therapy approach with immobilized biologicals. Med Res Rev. 2005;25:331–42.
Sinha P, Chornoguz O, Clements VK, Artemenko KA, Zubarev RA, Ostrand-Rosenberg S. Myeloid-derived suppressor cells express the death receptor Fas and apoptose in response to T cell-expressed FasL. Blood. 2011;117:5381–90.
Zhang Y, Liu Q, Zhang M, Yu Y, Liu X, Cao X. Fas signal promotes lung cancer growth by recruiting myeloid-derived suppressor cells via cancer cell-derived PGE2. J Immunol. 2009;182:3801–8.
Obermajer N, Wong JL, Edwards RP, Odunsi K, Moysich K, Kalinski P. PGE(2)-driven induction and maintenance of cancer-associated myeloid-derived suppressor cells. Immunol Invest. 2012;41:635–57.
Liu K. Role of apoptosis resistance in immune evasion and metastasis of colorectal cancer. World J Gastrointest Oncol. 2010;2:399–406.
Oltvai ZN, Milliman CL, Korsmeyer SJ. Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death. Cell. 1993;74:609–19.
Ruvolo PP, Deng X, May WS. Phosphorylation of Bcl-2 and regulation of apoptosis. Leukemia. 2001;15:515–22.
Yin C, Knudson CM, Korsmeyer SJ, Van Dyke T. Bax suppresses tumorigenesis and stimulates apoptosis in vivo. Nature. 1997;385:637–40.
Pietenpol JA, Stewart ZA. Cell cycle checkpoint signaling: cell cycle arrest versus apoptosis. Toxicology. 2002;181-182:475–81.
Li Y, Rogoff HA, Keates S, Gao Y, Murikipudi S, Mikule K, et al. Suppression of cancer relapse and metastasis by inhibiting cancer stemness. Proc Natl Acad Sci USA. 2015;112:1839–44.
Schust J, Sperl B, Hollis A, Mayer TU, Berg T. Stattic: a small-molecule inhibitor of STAT3 activation and dimerization. Chem Biol. 2006;13:1235–42.
Condamine T, Mastio J, Gabrilovich DI. Transcriptional regulation of myeloid-derived suppressor cells. J Leukoc Biol. 2015;98:913–22.
Katz SC, Point GR, Cunetta M, Thorn M, Guha P, Espat NJ, et al. Regional CAR-T cell infusions for peritoneal carcinomatosis are superior to systemic delivery. Cancer Gene Ther. 2016;23:142–8.
Burga RA, Thorn M, Point GR, Guha P, Nguyen CT, Licata LA, et al. Liver myeloid-derived suppressor cells expand in response to liver metastases in mice and inhibit the anti-tumor efficacy of anti-CEA CAR-T. Cancer Immunol Immunother. 2015;64:817–29.
Guha P, Cunetta M, Somasundar P, Espat NJ, Junghans RP, Katz SC. Frontline Science: functionally impaired geriatric CAR-T cells rescued by increased alpha5beta1 integrin expression. J Leukoc Biol. 2017;102:201–208.
Hamilton JA. GM-CSF in inflammation and autoimmunity. Trends Immunol. 2002;23:403–8.
Zhao HF, Wang J, Tony ToSS. The phosphatidylinositol 3-kinase/Akt and c-Jun N-terminal kinase signaling in cancer: alliance or contradiction? (Review). Int J Oncol. 2015;47:429–36.
Ilkovitch D, Lopez DM. The liver is a site for tumor-induced myeloid-derived suppressor cell accumulation and immunosuppression. Cancer Res. 2009;69:5514–21.
Connolly MK, Mallen-St Clair J, Bedrosian AS, Malhotra A, Vera V, Ibrahim J, et al. Distinct populations of metastases-enabling myeloid cells expand in the liver of mice harboring invasive and preinvasive intra-abdominal tumor. J Leukoc Biol. 2010;87:713–25.
Ma C, Kapanadze T, Gamrekelashvili J, Manns MP, Korangy F, Greten TF. Anti-Gr1 antibody depletion fails to eliminate hepatic myeloid-derived suppressor cells in tumor-bearing mice. J Leukoc Biol. 2012;92:1199–206.
Suzuki E, Kapoor V, Jassar AS, Kaiser LR, Albelda SM. Gemcitabine selectively eliminates splenic Gr-1+/CD11b+myeloid suppressor cells in tumor-bearing animals and enhances antitumor immune activity. Clin Cancer Res. 2005;11:6713–21.
Vincent J, Mignot G, Chalmin F, Ladoire S, Bruchard M, Chevriaux A, et al. 5-Fluorouracil selectively kills tumor-associated myeloid-derived suppressor cells resulting in enhanced T cell-dependent antitumor immunity. Cancer Res. 2010;70:3052–61.
Ji T, Gong D, Han Z, Wei X, Yan Y, Ye F, et al. Abrogation of constitutive Stat3 activity circumvents cisplatin resistant ovarian cancer. Cancer Lett. 2013;341:231–9.
Zhang Y, Jin Z, Zhou H, Ou X, Xu Y, Li H, et al. Suppression of prostate cancer progression by cancer cell stemness inhibitor napabucasin. Cancer Med. 2016;5:1251–8.
Jinushi M, Chiba S, Yoshiyama H, Masutomi K, Kinoshita I, Dosaka-Akita H, et al. Tumor-associated macrophages regulate tumorigenicity and anticancer drug responses of cancer stem/initiating cells. Proc Natl Acad Sci USA. 2011;108:12425–30.
Kujawski M, Zhang C, Herrmann A, Reckamp K, Scuto A, Jensen M, et al. Targeting STAT3 in adoptively transferred T cells promotes their in vivo expansion and antitumor effects. Cancer Res. 2010;70:9599–610.
Gotthardt D, Putz EM, Straka E, Kudweis P, Biaggio M, Poli V, et al. Loss of STAT3 in murine NK cells enhances NK cell-dependent tumor surveillance. Blood. 2014;124:2370–9.
Ostrand-Rosenberg S, Sinha P, Chornoguz O, Ecker C. Regulating the suppressors: apoptosis and inflammation govern the survival of tumor-induced myeloid-derived suppressor cells (MDSC). Cancer Immunol Immunother. 2012;61:1319–25.
Elmore S. Apoptosis: a review of programmed cell death. Toxicol Pathol. 2007;35:495–516.
Ye TH, Yang FF, Zhu YX, Li YL, Lei Q, Song XJ, et al. Inhibition of Stat3 signaling pathway by nifuroxazide improves antitumor immunity and impairs colorectal carcinoma metastasis. Cell Death Dis. 2017;8:e2534.
Nielsen M, Kaestel CG, Eriksen KW, Woetmann A, Stokkedal T, Kaltoft K, et al. Inhibition of constitutively activated Stat3 correlates with altered Bcl-2/Bax expression and induction of apoptosis in mycosis fungoides tumor cells. Leukemia. 1999;13:735–8.
Rao L, White E. Bcl-2 and the ICE family of apoptotic regulators: making a connection. Curr Opin Genet Dev. 1997;7:52–8.
Kroemer G, Zamzami N, Susin SA. Mitochondrial control of apoptosis. Immunol Today. 1997;18:44–51.
Brenner B, Koppenhoefer U, Weinstock C, Linderkamp O, Lang F, Gulbins E. Fas- or ceramide-induced apoptosis is mediated by a Rac1-regulated activation of Jun N-terminal kinase/p38 kinases and GADD153. J Biol Chem. 1997;272:22173–81.
Juo P, Kuo CJ, Reynolds SE, Konz RF, Raingeaud J, Davis RJ, et al. Fas activation of the p38 mitogen-activated protein kinase signalling pathway requires ICE/CED-3 family proteases. Mol Cell Biol. 1997;17:24–35.
Salmon RA, Foltz IN, Young PR, Schrader JW. The p38 mitogen-activated protein kinase is activated by ligation of the T or B lymphocyte antigen receptors, Fas or CD40, but suppression of kinase activity does not inhibit apoptosis induced by antigen receptors. J Immunol. 1997;159:5309–17.
Toyoshima F, Moriguchi T, Nishida E. Fas induces cytoplasmic apoptotic responses and activation of the MKK7-JNK/SAPK and MKK6-p38 pathways independent of CPP32-like proteases. J Cell Biol. 1997;139:1005–15.
Hsu SC, Gavrilin MA, Tsai MH, Han J, Lai MZ. p38 mitogen-activated protein kinase is involved in Fas ligand expression. J Biol Chem. 1999;274:25769–76.
Ivanov VN, Ronai Z. p38 protects human melanoma cells from UV-induced apoptosis through down-regulation of NF-kappaB activity and Fas expression. Oncogene. 2000;19:3003–12.
Cahill MA, Peter ME, Kischkel FC, Chinnaiyan AM, Dixit VM, Krammer PH, et al. CD95 (APO-1/Fas) induces activation of SAP kinases downstream of ICE-like proteases. Oncogene. 1996;13:2087–96.
Lenczowski JM, Dominguez L, Eder AM, King LB, Zacharchuk CM, Ashwell JD. Lack of a role for Jun kinase and AP-1 in Fas-induced apoptosis. Mol Cell Biol. 1997;17:170–81.
Low W, Smith A, Ashworth A, Collins M. JNK activation is not required for Fas-mediated apoptosis. Oncogene. 1999;18:3737–41.
Gardai SJ, Hildeman DA, Frankel SK, Whitlock BB, Frasch SC, Borregaard N, et al. Phosphorylation of Bax Ser184 by Akt regulates its activity and apoptosis in neutrophils. J Biol Chem. 2004;279:21085–95.
Parikh N, Sade H, Kurian L, Sarin A. The Bax N terminus is required for negative regulation by the mitogen-activated protein kinase kinase and Akt signaling pathways in T cells. J Immunol. 2004;173:6220–7.
Wittig I, Groner B. Signal transducer and activator of transcription 5 (STAT5), a crucial regulator of immune and cancer cells. Curr Drug Targets Immune Endocr Metabol Disord. 2005;5:449–63.
Chipoy C, Brounais B, Trichet V, Battaglia S, Berreur M, Oliver L, et al. Sensitization of osteosarcoma cells to apoptosis by oncostatin M depends on STAT5 and p53. Oncogene. 2007;26:6653–64.
Lee H, Pal SK, Reckamp K, Figlin RA, Yu H. STAT3: a target to enhance antitumor immune response. Curr Top Microbiol Immunol. 2011;344:41–59.
He G, Karin M. NF-kappaB and STAT3 - key players in liver inflammation and cancer. Cell Res. 2011;21:159–68.
Kujawski M, Kortylewski M, Lee H, Herrmann A, Kay H, Yu H. Stat3 mediates myeloid cell-dependent tumor angiogenesis in mice. J Clin Invest. 2008;118:3367–77.
O’Farrell AM, Liu Y, Moore KW, Mui AL. IL-10 inhibits macrophage activation and proliferation by distinct signaling mechanisms: evidence for Stat3-dependent and -independent pathways. EMBO J. 1998;17:1006–18.
Lang R, Patel D, Morris JJ, Rutschman RL, Murray PJ. Shaping gene expression in activated and resting primary macrophages by IL-10. J Immunol. 2002;169:2253–63.
Wang T, Niu G, Kortylewski M, Burdelya L, Shain K, Zhang S, et al. Regulation of the innate and adaptive immune responses by Stat-3 signaling in tumor cells. Nat Med. 2004;10:48–54.
Kortylewski M, Xin H, Kujawski M, Lee H, Liu Y, Harris T, et al. Regulation of the IL-23 and IL-12 balance by Stat3 signaling in the tumor microenvironment. Cancer Cell. 2009;15:114–23.
Langowski JL, Zhang X, Wu L, Mattson JD, Chen T, Smith K, et al. IL-23 promotes tumour incidence and growth. Nature. 2006;442:461–5.
Hu X, Bardhan K, Paschall AV, Yang D, Waller JL, Park MA, et al. Deregulation of apoptotic factors Bcl-xL and Bax confers apoptotic resistance to myeloid-derived suppressor cells and contributes to their persistence in cancer. J Biol Chem. 2013;288:19103–15.
Boyman O, Sprent J. The role of interleukin-2 during homeostasis and activation of the immune system. Nat Rev Immunol. 2012;12:180–90.
Zhao C, Xiao H, Wu X, Li C, Liang G, Yang S, et al. Rational combination of MEK inhibitor and the STAT3 pathway modulator for the therapy in K-Ras mutated pancreatic and colon cancer cells. Oncotarget. 2015;6:14472–87.
Ma Q, DeMarte L, Wang Y, Stanners CP, Junghans RP. Carcinoembryonic antigen-immunoglobulin Fc fusion protein (CEA-Fc) for identification and activation of anti-CEA immunoglobulin-T-cell receptor-modified T cells, representative of a new class of Ig fusion proteins. Cancer Gene Ther. 2004;11:297–306.
Acknowledgements
The authors thank Sorrento Therapeutics, Inc. for generously preparing the CEA-Fc for anti-CEA CAR detection and Prometheus, Inc. for providing Proleukin (IL2). We also thank Dr. John Morgan and Roger Williams Medical Center Core Facility for providing us with the flow cytometry core facility. Support for this work was provided by the National Institutes of Health (1K08CA160662-01A1).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Electronic supplementary material
Rights and permissions
About this article
Cite this article
Guha, P., Gardell, J., Darpolor, J. et al. STAT3 inhibition induces Bax-dependent apoptosis in liver tumor myeloid-derived suppressor cells. Oncogene 38, 533–548 (2019). https://doi.org/10.1038/s41388-018-0449-z
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41388-018-0449-z
This article is cited by
-
Evolving cognition of the JAK-STAT signaling pathway: autoimmune disorders and cancer
Signal Transduction and Targeted Therapy (2023)
-
The role of myeloid-derived suppressor cells in liver cancer
Discover Oncology (2023)
-
Immunosuppressive cells in cancer: mechanisms and potential therapeutic targets
Journal of Hematology & Oncology (2022)
-
The biology of YAP in programmed cell death
Biomarker Research (2022)
-
Inhibition of STAT3Y705 phosphorylation by Stattic suppresses proliferation and induces mitochondrial-dependent apoptosis in pancreatic cancer cells
Cell Death Discovery (2022)