Tumor-derived Granulocyte Colony-stimulating Factor Research Articles

Redox-responsive nanoassembly restrained myeloid-derived suppressor cells recruitment through autophagy-involved lactate dehydrogenase A silencing for enhanced cancer immunochemotherapy

Myeloid-derived suppressor cells (MDSCs) are the chief accomplices for assisting tumor's survival and suppressing anti-tumor immunity, which can be recruited by tumor-derived cytokines, such as granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF). The plentiful lactate dehydrogenase A (LDHA) in glycolysis is usually accompanied by abundant tumor-derived G-CSF and GM-CSF, further promoting MDSCs recruitment and immunosuppression. Herein, with the aim to achieve powerful anti-tumor immunity, an immunochemotherapy regimen basing on a redox-responsive nanoassembly (R-mPDV/PDV/DOX/siL) is developed, which integrates the combined strategy of restraining cytokines-mediated MDSCs recruitment through LDHA silencing and reinforcing tumor immunogenicity through anthracycline (DOX)-elicited immunogenic cell death (ICD) effects. This redox-responsive nanoassembly is self-assembled by three glutathione (GSH)-responsive polymers, which employ poly(δ-valerolactone) (PVL) as hydrophobic segment and 3, 3′-dithiodipropionic acid (DA) as linkage to connect hydrophilic segment. DOX is encapsulated in the core and LDHA siRNA (siL) is effectively compressed by cationic PAMAM. The cellular internalization and tumor-homing are strengthened by the specific recognition on integrin (αvβ3) by c(RGDfk) (RGD) ligand. After escaping from endosomes/lysosomes, R-mPDV/PDV/DOX/siL is disintegrated through GSH-elicited cleavage of DA, realizing burst release of drugs and high-efficient LDHA silencing. The reduced expression of LDHA suppresses the generation of G-CSF and GM-CSF cytokines, restrains MDSCs recruitment and reinforces anti-tumor immunity. Eventually, this therapeutic regimen of DOX and siL on R-mPDV/PDV/DOX/siL nanoassembly achieved powerful anti-tumor efficiency on 4 T1 orthotopic tumor, opening the new horizons for immunochemotherapy.

Prognostic significance of bone marrow FDG uptake in patients with gynecological cancer

We investigated the prognostic significance and the underlying mechanism of increased bone marrow (BM) 2-(18F) fluoro-2-deoxy-D-glucose as a tracer (FDG)-uptake in patients with gynecological cancer. A list of patients diagnosed with cervical, endometrial, and ovarian cancer from January 2008 to December 2014 were identified. Then, through chart reviews, 559 patients who underwent staging by FDG-positron emission tomography (PET)/computed tomography (CT) and subsequent surgical resection were identified, and their clinical data were reviewed retrospectively. BM FDG-uptake was evaluated using maximum standardized uptake value (SUVmax) and BM-to-aorta uptake ratio (BAR). As a result, we have found that increased BAR was observed in 20 (8.7%), 21 (13.0%), 21 (12.6%) of cervical, endometrial, and ovarian cancer, respectively, and was associated with significantly shorter survival. Increased BAR was also closely associated with increased granulopoiesis. In vitro and in vivo experiments revealed that tumor-derived granulocyte colony-stimulating factor (G-CSF) was involved in the underlying causative mechanism of increased BM FDG-uptake, and that immune suppression mediated by G-CSF-induced myeloid-derived suppressor cells (MDSCs) is responsible for the poor prognosis of this type of cancer. In conclusion, increased BM FDG-uptake, as represented by increased BAR, is an indicator of poor prognosis in patients with gynecological cancer.

Contrasting Immunopathogenic and Therapeutic Roles of Granulocyte Colony-Stimulating Factor in Cancer.

Tumor cells are particularly adept at exploiting the immunosuppressive potential of neutrophils as a strategy to achieve uncontrolled proliferation and spread. Recruitment of neutrophils, particularly those of an immature phenotype, known as granulocytic myeloid-derived suppressor cells, is achieved via the production of tumor-derived granulocyte colony-stimulating factor (G-CSF) and neutrophil-selective chemokines. This is not the only mechanism by which G-CSF contributes to tumor-mediated immunosuppression. In this context, the G-CSF receptor is expressed on various cells of the adaptive and innate immune systems and is associated with induction of T cell polarization towards the Th2 and regulatory T cell (Treg) phenotypes. In contrast to the potentially adverse effects of sustained, endogenous production of G-CSF by tumor cells, stringently controlled prophylactic administration of recombinant (r) G-CSF is now a widely practiced strategy in medical oncology to prevent, and in some cases treat, chemotherapy-induced severe neutropenia. Following an overview of the synthesis, structure and function of G-CSF and its receptor, the remainder of this review is focused on: (i) effects of G-CSF on the cells of the adaptive and innate immune systems; (ii) mechanisms by which this cytokine promotes tumor progression and invasion; and (iii) current clinical applications and potential risks of the use of rG-CSF in medical oncology.

TMIC-35. IDH1 MUTATION IN GLIOMA REPROGRAMS EARLY MYELOID DIFFERENTIATION IN THE BONE MARROW (BM) TO PRODUCE NON-IMUNESUPPRESSIVE NEUTROPHILS

Abstract Gliomas are the most common primary brain tumors; patients exhibit a poor prognosis. Mutations in isocitrate dehydrogenase (mIDH) are present in most patients with lower grade glioma (LGG), and are correlated with better prognosis and survival. We postulated that mIDH1 induces epigenetic reprogramming leading to alteration in immune cells’ function. To examine the role of mIDH1 in the tumor immune microenvironment (TME), we generated LGG glioma models using the sleeping beauty system (Koschmann et al., 2016, Nunez et al., 2019). We show that mIDH1 gliomas exhibit increased levels of CD11b+ Gr1+ myeloid derived suppressor cells in the tumor, BM, circulation and spleen of mice. We found that mIDH1 modifies the cytokines’ repertoire in the glioma microenvironment altering the phenotype and function of the tumor infiltrating CD45+/CD11b+/Gr-1+ myeloid cells, rendering them non-immunosuppressive. Production of these cells results from activation of the granulocytic differentiation program in the BM. This novel mechanism is mediated by tumor-derived granulocyte-colony stimulating factor (G-CSF) which elicits expansion and differentiation of hematopoietic stem cells, skewing hematopoiesis towards the immature myeloid lineage. Moreover, mIDH1 glioma derived G-CSF causes mobilization of hematopoietic stem cells (HSCs) and myeloid progenitors (MPs) from BM to spleen. Blocking G-CSF in mIDH1 bearing mice significantly restored HSCs, and MPs frequencies in the spleen to levels encountered in wtIDH1 glioma. Interestingly, blocking G-CSF restored the inhibitory function of the granulocytic CD11b+ Gr-1+ in mIDH1, and shortened the median survival (MS) of mIDH1 bearing mice to the same MS encountered in wtIDH1 glioma. Our results provide insights into novel epigenetic alterations triggered by mIDH1 which regulate myeloid cells’ heterogeneity and immunosuppression; a feature that can be harnessed to develop novel immunotherapeutic strategies.

The role of myeloid-derived suppressor cells in endometrial cancer displaying systemic inflammatory response: clinical and preclinical investigations

ABSTRACTSystemic inflammatory responses including thrombocytosis, leukocytosis, or neutrophilia have gained attention as prognostic indicators in patients with various solid malignancies.current study, we aimed to investigate the clinical implications and underlying biological mechanism of the systemic inflammatory response in endometrial cancer. Clinical data from 900 patients with endometrial cancer were analyzed to investigate the association between pretreatment leukocytosis, thrombocytosis, and treatment outcome. Clinical samples, endometrial cancer cell lines, and a mouse model of endometrial cancer were used to examine the mechanisms responsible for systemic inflammatory response in endometrial cancer, focusing on the role of tumor-derived granulocyte colony-stimulating factor (G-CSF) and MDSCs. Then, we showed that pretreatment concurrent leukocytosis and thrombocytosis is associated with significantly shorter survival and decreased chemosensitivity among patients with endometrial cancer. In vitro and in vivo experiments revealed that tumor-derived G-CSF and G-CSF-mediated IL-6 production from the tumor microenvironment are involved in the development of leukocytosis and thrombocytosis in patients with endometrial cancer. Moreover, increased tumor-infiltrating MDSCs induced by tumor-derived G-CSF, MDSC-mediated T cell suppression, and MDSC-mediated cancer stem cell induction are responsible for progression and chemoresistance in this type of endometrial cancer. MDSC depletion using an anti-Gr-1 neutralizing antibody or inhibition of MDSC activity by celecoxib inhibited tumor growth and enhanced chemosensitivity in endometrial cancer displaying concurrent leukocytosis and thrombocytosis. In conclusion, Pretreatment concurrent leukocytosis and thrombocytosis are associated with significantly shorter survival and decreased chemosensitivity among patients with endometrial cancer. Combining MDSC-targeting treatments with current standard chemotherapies might have therapeutic efficacy for these patients.

Tumor-derived granulocyte colony-stimulating factor diminishes efficacy of breast tumor cell vaccines

BackgroundAlthough metastasis is ultimately responsible for about 90% of breast cancer mortality, the vast majority of breast-cancer-related deaths are due to progressive recurrences from non-metastatic disease. Current adjuvant therapies are unable to prevent progressive recurrences for a significant fraction of patients with breast cancer. Autologous tumor cell vaccines (ATCVs) are a safe and potentially useful strategy to prevent breast cancer recurrence, in a personalized and patient-specific manner, following standard-of-care tumor resection. Given the high intra-patient and inter-patient heterogeneity in breast cancer, it is important to understand which factors influence the immunogenicity of breast tumor cells in order to maximize ATCV effectiveness.MethodsThe relative immunogenicity of two murine breast carcinomas, 4T1 and EMT6, were compared in a prophylactic vaccination-tumor challenge model. Differences in cell surface expression of antigen-presentation-related and costimulatory molecules were compared along with immunosuppressive cytokine production. CRISPR/Cas9 technology was used to modulate tumor-derived cytokine secretion. The impacts of cytokine deletion on splenomegaly, myeloid-derived suppressor cell (MDSC) accumulation and ATCV immunogenicity were assessed.ResultsMice vaccinated with an EMT6 vaccine exhibited significantly greater protective immunity than mice vaccinated with a 4T1 vaccine. Hybrid vaccination studies revealed that the 4T1 vaccination induced both local and systemic immune impairments. Although there were significant differences between EMT6 and 4T1 in the expression of costimulatory molecules, major disparities in the secretion of immunosuppressive cytokines likely accounts for differences in immunogenicity between the cell lines. Ablation of one cytokine in particular, granulocyte-colony stimulating factor (G-CSF), reversed MDSC accumulation and splenomegaly in the 4T1 model. Furthermore, G-CSF inhibition enhanced the immunogenicity of a 4T1-based vaccine to the extent that all vaccinated mice developed complete protective immunity.ConclusionsBreast cancer cells that express high levels of G-CSF have the potential to diminish or abrogate the efficacy of breast cancer ATCVs. Fortunately, this study demonstrates that genetic ablation of immunosuppressive cytokines, such as G-CSF, can enhance the immunogenicity of breast cancer cell-based vaccines. Strategies that combine inhibition of immunosuppressive factors with immune stimulatory co-formulations already under development may help ATCVs reach their full potential.

Abstract B13: Plasma G-CSF levels are predictive of lack of response to zoledronic acid treatment in reducing breast cancer recurrence

Abstract Some breast cancer patients have no evidence of metastatic disease at the time of original diagnosis, yet ~30-40% of patients will experience recurrent breast cancer. Over 90% of breast cancer deaths occur due to distant spread of the disease, and bone is the most common site of breast cancer metastasis. Bisphosphonates, such as zoledronic acid (ZA), are used to treat patients with osteolytic disease, including metastatic breast cancer. ZA has been demonstrated to reduce disseminated tumor cells (DTCs) and breast cancer recurrence, but not all patients see this benefit and it is not yet clear what predicts benefit from adjuvant ZA treatment; the mechanism of action for this effect of ZA in reducing breast cancer remains undetermined. Here, we establish that ZA renders osteoclast progenitor cells (OCPs) tumor suppressive, primarily by directing their lineage potential. In instances where the OCP lineage potential was modulated via systemic or tumor-derived granulocyte-colony stimulating factor (G-CSF), OCPs did not differentiate into tumor-suppressive populations but instead into mature osteoclasts. High G-CSF was sufficient to abrogate the tumor-suppressive effect of ZA. Furthermore, we determined that in a subset of patient plasma samples from the AZURE clinical trial where stage II/III breast cancer patients were randomized to receive standard systemic treatment alone with adjuvant ZA treatment, patients who had baseline plasma G-CSF levels >23 pg/mL had reduced disease-free survival as assessed over a 10-year period post treatment initiation compared to patients with baseline plasma G-CSF levels <23 pg/mL (p=0.02). These findings indicate that patients with higher baseline plasma G-CSF levels will not likely observe reduction in breast cancer recurrence with adjuvant ZA treatment, and in fact may have worse prognosis with adjuvant ZA treatment as compared to control treatment. Our data are the first to demonstrate that ZA mediates its tumor-suppressive function via the OCP population and implicate capitalizing on the differentiation potential of the OCPs to maximize patient response to adjuvant ZA treatment in breast cancer risk of recurrence. Citation Format: Jessalyn M. Ubellacker, Ninib Baryawno, Nicolas Severe, Molly J. DeCristo, Jaclyn Sceneay, Marie-Therese Haider, Catherine S. Rhee, Yuanbo Qin, Ingunn Holen, Walter M. Gregory, Janet E. Brown, Robert E. Coleman, David T. Scadden, Sandra S. McAllister. Plasma G-CSF levels are predictive of lack of response to zoledronic acid treatment in reducing breast cancer recurrence [abstract]. In: Proceedings of the AACR Special Conference: Advances in Breast Cancer Research; 2017 Oct 7-10; Hollywood, CA. Philadelphia (PA): AACR; Mol Cancer Res 2018;16(8_Suppl):Abstract nr B13.

Tongue squamous cell carcinoma producing both parathyroid hormone-related protein and granulocyte colony-stimulating factor: a case report and literature review

BackgroundParaneoplastic syndrome generally results from tumor-derived hormones or peptides that cause metabolic derangements. Common metabolic conditions include hyponatremia, hypercalcemia, hypoglycemia, and Cushing’s syndrome. Herein, we report a very rare case of tongue carcinoma presenting with leukocytosis and hypercalcemia.Case presentationA 57-year-old man was admitted to our hospital with tongue squamous cell carcinoma (cT4aN0M0, stage IV). He underwent radical resection following preoperative chemoradiotherapy, but locoregional recurrence was detected 2 months after surgery. He presented with marked leukocytosis and hypercalcemia with elevated serum levels of granulocyte colony-stimulating factor (G-CSF) and parathyroid hormone-related protein (PTHrP). He was therefore managed with intravenous fluids, furosemide, prednisolone, elcatonin, and pamidronate. However, the patient died 1 month later of carcinomatous pleuritis following distant metastasis to the lung. Immunohistochemical analyses of the resected specimens revealed positive staining for PTHrP and G-CSF in the cancer cells.ConclusionsIn this case, it was considered that tumor-derived G-CSF and PTHrP caused leukocytosis and hypercalcemia.

The significance of G-CSF expression and myeloid-derived suppressor cells in the chemoresistance of uterine cervical cancer.

Granulocyte-colony stimulating factor (G-CSF) producing malignant tumor has been reported to occur in various organs, and has been associated with poor clinical outcome. The aim of this study is to investigate the significance of tumor G-CSF expression in the chemosensitivity of uterine cervical cancer. The clinical data of recurrent or advanced cervical cancer patients who were treated with platinum-based chemotherapy were analyzed. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were employed to examine the mechanisms responsible for the development of chemoresistance in G-CSF-producing cervical cancer, focusing on myeloid-derived suppressor cells (MDSC). As a result, the tumor G-CSF expression was significantly associated with increased MDSC frequencies and compromised survival. In vitro and in vivo experiments demonstrated that the increased MDSC induced by tumor-derived G-CSF is involved in the development of chemoresistance. The depletion of MDSC via splenectomy or the administration of anti-Gr-1 antibody sensitized G-CSF-producing cervical cancer to cisplatin. In conclusion, tumor G-CSF expression is an indicator of an extremely poor prognosis in cervical cancer patients that are treated with chemotherapy. Combining MDSC-targeting treatments with current standard chemotherapies might have therapeutic efficacy as a treatment for G-CSF-producing cervical cancer.

Abstract 3358: SOCS3 deficiency in myeloid cells promotes tumor development: Involvement of STAT3 activation and myeloid-derived suppressor cells

Abstract Suppressor Of Cytokine Signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and generally function as tumor suppressors. The absence of SOCS3 in particular leads to heightened activation of the STAT3 transcription factor, which has a striking ability to promote tumor survival while suppressing anti-tumor immunity. We report for the first time that genetic deletion of SOCS3 specifically in myeloid cells significantly enhances tumor growth, which correlates with elevated levels of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, and diminished CD8+ T-cell infiltration in tumors. Furthermore, SOCS3-deficient bone-marrow-derived cells exhibit heightened STAT3 activation and preferentially differentiate into the Gr-1+CD11b+Ly6G+ MDSC phenotype. Importantly, we identify granulocyte-colony stimulating factor (G-CSF) as a critical factor secreted by the tumor microenvironment that promotes development of MDSC via a STAT3-dependent pathway. Abrogation of tumor-derived G-CSF reduces the proliferation and accumulation of Gr-1+CD11b+ MDSC and inhibits tumor growth. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, via inhibition of STAT3 activation. Note: This abstract was not presented at the meeting. Citation Format: Hao Yu, Hongwei Qin, Etty (Tika) Benveniste. SOCS3 deficiency in myeloid cells promotes tumor development: Involvement of STAT3 activation and myeloid-derived suppressor cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3358. doi:10.1158/1538-7445.AM2015-3358

SOCS3 deficiency in myeloid cells promotes tumor development: involvement of STAT3 activation and myeloid-derived suppressor cells (TUM6P.1000)

Abstract Suppressor Of Cytokine Signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and generally function as tumor suppressors. The absence of SOCS3 in particular leads to heightened activation of the STAT3 transcription factor, which has a striking ability to promote tumor survival while suppressing anti-tumor immunity. We report for the first time that genetic deletion of SOCS3 specifically in myeloid cells significantly enhances tumor growth, which correlates with elevated levels of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, and diminished CD8+ T-cell infiltration in tumors. Furthermore, SOCS3-deficient bone-marrow-derived cells exhibit heightened STAT3 activation and preferentially differentiate into the Gr-1+CD11b+Ly6G+ MDSC phenotype. Importantly, we identify granulocyte-colony stimulating factor (G-CSF) as a critical factor secreted by the tumor microenvironment that promotes development of MDSC via a STAT3-dependent pathway. Abrogation of tumor-derived G-CSF reduces the proliferation and accumulation of Gr-1+CD11b+ MDSC and inhibits tumor growth. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, via inhibition of STAT3 activation.

Abstract B51: SOCS3 deficiency in myeloid cells promotes prostate tumor development

Abstract Suppressor Of Cytokine Signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and have been implicated as functioning as tumor suppressors, particularly SOCS3. We have previously demonstrated that specific deletion of SOCS3 in myeloid cell leads to heightened activation of STAT3 and downstream STAT3 target gene expression. STAT3 activation has been strongly implicated in contributing to prostate cancer progression and metastasis. STAT3 signaling in myeloid cells has been demonstrated to attenuate anti-tumor immunity. Thus, we evaluated the impact of SOCS3 deletion in myeloid cells in a murine prostate tumor model. We demonstrate that prostate tumor growth is significantly enhanced in myeloid-specific SOCS3-deficient mice, which correlates with elevated levels of Myeloid Derived Suppressor Cells (MDSC) in both the spleen and tumor microenvironment, and less CD8+ T-cell infiltration in tumors. Furthermore, SOCS3-deficient bone-marrow-derived mononuclear cells exhibit heightened STAT3 activation and are preferentially differentiate into MDSC phenotype. Importantly, we identify granulocyte-colony stimulating factor (G-CSF) as a critical factor secreted by the prostate tumor microenvironment that promotes development of Gr-1+CD11b+ cells via a STAT3-depentent pathway. Abrogation of tumor-derived G-CSF reduced the proliferation and accumulation of Gr-1+CD11b+ cells and inhibited prostate tumor growth. Therefore, the tumor-derived cytokine, G-CSF, is a prospective candidate upstream of the STAT3/SOCS3 pathway in MDSC differentiation from the bone marrow. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, which may contribute to tumor suppressor attributes of SOCS3. Citation Format: Hao Yu, Yudong Liu, Jessy Deshane, Etty (Tika) Benveniste, Hongwei Qin. SOCS3 deficiency in myeloid cells promotes prostate tumor development. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B51. doi:10.1158/1538-7445.CHTME14-B51

Abstract A25: SOCS3 deficiency in myeloid cells promotes prostate tumor development

Abstract Suppressor Of Cytokine Signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and have been implicated as functioning as tumor suppressors, particularly SOCS3. We have previously demonstrated that specific deletion of SOCS3 in myeloid cells leads to heightened activation of STAT3 and downstream STAT3 target gene expression. STAT3 activation has been strongly implicated in contributing to prostate cancer progression and metastasis. STAT3 signaling in myeloid cells has been demonstrated to attenuate anti-tumor immunity. Thus, we evaluated the impact of SOCS3 deletion in myeloid cells in a murine prostate tumor model. We demonstrate that prostate tumor growth is significantly enhanced in myeloid-specific SOCS3-deficient mice, which correlates with elevated levels of Myeloid Derived Suppressor Cells (MDSC) in both the spleen and tumor microenvironment, and less CD8+ T-cell infiltration in tumors. Furthermore, SOCS3-deficient bone-marrow-derived mononuclear cells exhibit heightened STAT3 activation and are preferentially differentiate into MDSC phenotype. Importantly, we identify granulocyte-colony stimulating factor (G-CSF) as a critical factor secreted by the prostate tumor microenvironment that promotes development of Gr-1+CD11b+ cells via a STAT3-depentent pathway. Abrogation of tumor-derived G-CSF reduced the proliferation and accumulation of Gr-1+CD11b+ cells and inhibited prostate tumor growth. Therefore, the tumor-derived cytokine, G-CSF, is a prospective candidate upstream of the STAT3/SOCS3 pathway in MDSC differentiation from the bone marrow. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, which may contribute to tumor suppressor attributer of SOCS3. Citation Format: Hao Yu, Yudong Liu, Braden C. McFarland, Etty N. Benveniste, Hongwei Qin. SOCS3 deficiency in myeloid cells promotes prostate tumor development. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A25. doi:10.1158/1538-7445.CHTME14-A25

Abstract 1103: MDSC targeting therapy for uterine cervical cancer displaying TRL

Abstract Objectives: The aim of this study was to investigate the clinical implications and underlying mechanism of tumor-related-leukocytosis (TRL) in cervical cancer. Methods: The clinical data of cervical cancer patients who were treated with definitive radiotherapy were analyzed to investigate the association between TRL and treatment outcome in retrospective and prospective settings. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were employed to examine the mechanisms responsible for TRL in cervical cancer, focusing on the myeloid-derived suppressor cell (MDSC) and tumor-derived granulocyte colony-stimulating factor(G-CSF). Results: TRL was significantly associated with shorter survival. The TRL-positive patients displayed upregulated tumor G-CSF expression and elevated serum G-CSF levels and increased MDSC frequencies in the blood compared with the TRL-negative patients. In vitro and in vivo investigations revealed that tumor-derived G-CSF is involved in the underlying causative mechanism of TRL and that the increase in the number of MDSC induced by tumor-derived G-CSF is responsible for the rapidly progressive nature of TRL-positive cervical cancer. The administration of anti-Gr-1 antibody or the depletion of MDSC by splenectomy significantly inhibited tumor growth in TRL-positive cervical cancer. Conclusion: TRL is an indicator of a poor prognosis in cervical cancer patients treated with definitive radiotherapy. MDSC induced by tumor-derived G-CSF is responsible for the rapidly progressive nature of TRL-positive cervical cancer. MDSC-targeting treatments might have therapeutic potential in TRL-positive cervical cancer. Note: This abstract was not presented at the meeting. Citation Format: Yuri Matsumoto, Mahiru Kawano, Tomoyuki Sasano, Seiji Mabuchi. MDSC targeting therapy for uterine cervical cancer displaying TRL. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1103. doi:10.1158/1538-7445.AM2014-1103

Abstract 1068: Socs3 deficiency in myeloid cells promotes prostate tumor development

Abstract Suppressor Of Cytokine Signaling (SOCS) proteins are negative regulators of the JAK/STAT pathway, and have been implicated as functioning as tumor suppressors, particularly SOCS3. We have previously demonstrated that specific deletion of SOCS3 in myeloid cells leads to heightened activation of STAT3 and downstream STAT3 target gene expression. STAT3 activation has been strongly implicated in contributing to prostate cancer progression and metastasis. STAT3 signaling in myeloid cells has been demonstrated to attenuate anti-tumor immunity. Thus, we evaluated the impact of SOCS3 deletion in myeloid cells in a murine prostate tumor model. We demonstrate that prostate tumor growth is significantly enhanced in myeloid-specific SOCS3-deficient mice, which correlates with elevated levels of Myeloid Derived Suppressor Cells (MDSC) in both the spleen and tumor microenvironment, and less CD8+ T-cell infiltration in tumors. Furthermore, SOCS3-deficient bone-marrow-derived mononuclear cells exhibit heightened STAT3 activation and are preferentially differentiate into MDSC phenotype. Importantly, we identify granulocyte-colony stimulating factor (G-CSF) as a critical factor secreted by the prostate tumor microenvironment that promotes development of Gr-1+CD11b+ cells via a STAT3-depentent pathway. Abrogation of tumor-derived G-CSF reduced the proliferation and accumulation of Gr-1+CD11b+ cells and inhibited prostate tumor growth. Therefore, the tumor-derived cytokine, G-CSF, is a prospective candidate upstream of the STAT3/SOCS3 pathway in MDSC differentiation from the bone marrow. These findings highlight the critical function of SOCS3 as a negative regulator of MDSC development and function, which may contribute to tumor suppressor attributer of SOCS3. Citation Format: Hao Yu, Hongwei Qin. Socs3 deficiency in myeloid cells promotes prostate tumor development. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1068. doi:10.1158/1538-7445.AM2014-1068

Uterine cervical cancer displaying tumor-related leukocytosis: a distinct clinical entity with radioresistant feature.

Tumor-related leukocytosis (TRL) is occasionally found in patients with nonhematopoietic malignancies. We investigated the clinical implication of TRL and individualized treatment for TRL-positive cervical cancer, as well as the underlying biological mechanism. Clinical data from 258 cervical cancer patients treated with definitive radiotherapy were analyzed to investigate the association between TRL and treatment outcome. Clinical samples, cervical cancer cell lines, and a mouse model of cervical cancer were used to examine the mechanisms responsible for TRL in cervical cancer, focusing on the role of tumor-derived granulocyte colony-stimulating factor (G-CSF) and myeloid-derived suppressor cells (MDSCs). All statistical tests were two-sided. TRL was statistically significantly associated with younger age (Wilcoxon rank sum test, P = .03), larger tumor size (Wilcoxon rank sum test, P = .006), advanced clinical stage (χ(2) test, P = .01), and shorter overall survival (Cox proportional hazard modeling and Wald tests, P < .001). Among cervical cancer patients, TRL was associated with upregulated tumor G-CSF expression (χ(2) test, P < .001), elevated serum G-CSF levels (Student t test, P = .03), larger spleens (Student t test, P = .045), and increased MDSC frequencies in the blood (Student t test, P < .001) compared with the TRL-negative patients. In vitro and in vivo experiments revealed that tumor-derived G-CSF was involved in the underlying causative mechanism of TRL and MDSCs induced by tumor-derived G-CSF are responsible for the rapidly progressive and radioresistant nature of TRL-positive cervical cancer. The administration of anti-Gr-1 neutralizing antibody or the depletion of MDSCs by splenectomy (n = 6 per group) inhibited tumor growth and enhanced radiosensitivity in TRL-positive cervical cancer xenografts (Wilcoxon rank sum test, P = .008 and P = .02, respectively). TRL is associated with resistance to radiotherapy among cervical cancer patients, and MDSC-targeting treatments may have therapeutic potential in these patients.

Extracellular signal-regulated kinase 2 mediates the expression of granulocyte colony-stimulating factor in invasive cancer cells

Granulocyte colony-stimulating factor (G-CSF) affects granulopoiesis and is important for mobilizing neutrophils into blood circulation. Due to the hematopoietic properties of G-CSF, it has been widely used to clinically treat chemotherapy-induced neutropenia. However, G-CSF can promote tumors by inhibiting innate and adaptive immunity and enhancing angiogenesis and neoplastic growth. Most G-CSF-producing tumors are associated with a poor prognosis. This indicates that G-CSF promotes cancer progression. Thus, identifying regulatory molecules involved in tumor-derived G-CSF expression may provide therapeutic targets for cancer treatment. This study identified considerable G-CSF expression in malignant breast, lung and oral cancer cells. However, G-CSF expression was barely detectable in non-invasive cell lines. Expression of G-CSF mRNA and protein increased during exposure to tumor necrosis factor-α (TNF-α). Treatment with U0126 (a mitogen-activated protein kinase inhibitor) drastically reduced basal levels of G-CSF and TNF-α-induced G-CSF in aggressive cancer cells. This study also showed that knockdown of extracellular signal-regulated kinase (ERK)2 by shRNA was necessary and sufficient to eliminate the expression of tumor-derived G-CSF. This did not apply to ERK1. Therefore, ERK2 (but not ERK1) is responsible for the transcriptional regulation of tumor-derived G-CSF. The results indicate the pharmaceutical value of specific ERK2 inhibitors in treating patients with G-CSF-producing tumors.

Expression of CD163 prevents apoptosis through the production of granulocyte colony-stimulating factor in meningioma

CD163 is a 130-kDa transmembrane protein expressed in human monocytes and macrophages, and the aberrant expression of CD163 in breast and colorectal cancer associated with patients' poor prognosis was reported. Here, we analyzed the expression of CD163 in meningioma, a common intracranial tumor, and its molecular mechanism in association with meningioma progression. First, we performed immunohistochemical analysis using 50 human meningioma specimens. Next, we established CD163-overexpressing human meningioma cell lines and investigated its roles in tumor progression in vitro and in vivo. Immunohistochemically, 26 of 50 human meningioma specimens (52.0%) were positive for CD163 in tumor cells, including benign grade I (48.5%) and grade II (71.4%) cases. Furthermore, CD163 expression was correlated with histological atypical parameters that directly predict the prognosis of meningioma. CD163-overexpressing meningioma cells showed significant suppression of apoptosis and accelerated tumor growth in nude mice. In addition, unexpected splenomegaly affiliated with the xenograft predicted tumor-derived granulocyte colony-stimulating factor (G-CSF) production, which was confirmed by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. To our knowledge, this is the first report that demonstrates CD163 expression in meningioma not only by immunohistochemistry but also by reverse-transcription polymerase chain reaction, using primary culture cells, and provides the novel molecular function of CD163 to prevent apoptosis through the production of G-CSF in meningioma.

Tumor-derived G-CSF promotes granulocytic MDSC development in vivo (66.34)

Abstract Myeloid-derived suppressor cells (MDSC) comprise a heterogeneous population of myeloid cells with the capacity to suppress tumor immunity. Consequently, these cells represent a significant impediment to effective cancer immunotherapy. While the mechanisms by which these cells mediate immunosuppression is well-established, details on how they develop remain poorly understood. Broadly speaking, it is known that tumor-derived factors play significant roles in diverse aspects of MDSC biology. Given that MDSC accumulation is a result of altered myelopoiesis and that a major subset is granulocytic, we tested the hypothesis that tumor-derived granulocyte-colony stimulating factor (G-CSF) promotes MDSC development. Using both implantable and autochthonous mouse mammary tumor models, we observed abundant amounts of G-CSF in vivo, which correlated with a massive accumulation of granulocytic MDSC. To determine a causal role of G-CSF in MDSC generation, we established both gain- and loss-of-function approaches. First, administration of recombinant G-CSF alone elicited immunosuppressive granulocytic MDSC. Secondly, over-expression of G-CSF in G-CSF-negative tumors led to granulocytic MDSC accumulation. Lastly, inhibiting G-CSF culminated in a significant reduction of granulocytic MDSC. Collectively, our studies demonstrate the importance of tumor-derived G-CSF in MDSC development, thus providing new insights into the identity of putative targets for therapeutic applications.