GM-CSF Production by Tumor Cells Is Associated with Improved Survival in Colorectal Cancer

Mucosal-associated invariant T cells modulate innate immune cells and inhibit colon cancer growth

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that can be activated by microbial antigens and cytokines and are abundant in mucosal tissues including the colon. MAIT cells have cytotoxic and pro-inflammatory functions and have potentials for use as adoptive cell therapy. However, studies into their anti-cancer activity, including their role in colon cancer, are limited. Using an animal model of colon cancer, we showed that peritumoral injection of in vivo-expanded MAIT cells into RAG1-/- mice with MC38-derived tumours inhibits tumour growth compared to control. Multiplex cytokine analyses showed that tumours from the MAIT cell-treated group have higher expression of markers for eosinophil-activating cytokines, suggesting a potential association between eosinophil recruitment and tumour inhibition. In a human peripheral leukocyte co-culture model, we showed that leukocytes stimulated with MAIT ligand showed an increase in eotaxin-1 production and activation of eosinophils, associated with increased cancer cell killing. In conclusion, we showed that MAIT cells have a protective role in a murine colon cancer model, associated with modulation of the immune response to cancer, potentially involving eosinophil-associated mechanisms. Our results highlight the potential of MAIT cells for non-donor restricted colon cancer immunotherapy.

Mechanisms underlying neutrophils adhesion to triple-negative breast cancer cells via CD11b-ICAM1 in promoting breast cancer progression

BACKGROUND

Triple-negative breast cancer (TNBC) is recognized as the most aggressive and immunologically infiltrated subtype of breast cancer. A high circulating neutrophil-to-lymphocyte ratio (NLR) is strongly linked to a poor prognosis among patients with breast cancer, emphasizing the critical role of neutrophils. Although the involvement of neutrophils in tumor metastasis is well documented, their interactions with primary tumors and tumor cells are not yet fully understood.

METHODS

Clinical data were analyzed to investigate the role of neutrophils in breast cancer. In vivo mouse model and in vitro co-culture system were used for mechanism researches. Blocking experiments were further performed to identify therapeutic agents against TNBC.

RESULTS

TNBC cells secreted GM-CSF to sustain the survival of mature neutrophils and upregulated CD11b expression. Through CD11b, neutrophils specifically binded to ICAM1 on TNBC cells, facilitating adhesion. Transcriptomic sequencing combined with human and murine functional experiments revealed that neutrophils, through direct CD11b-ICAM1 interactions, activated the MAPK signaling pathway in TNBC cells, thereby enhancing tumor cell invasion and migration. Atorvastatin effectively inhibited ICAM1 expression in tumor cells, and tumor cells with ICAM1 knockout or treated with atorvastatin were unresponsive to neutrophil activation. The MAPK pathway and MMP9 expression were significantly inhibited in the tumor tissues of TNBC patients treated with atorvastatin.

CONCLUSIONS

Targeting CD11b-ICAM1 with atorvastatin represented a potential clinical approach to reduce the malignant characteristics of TNBC.

Exploring the cross-cancer effect of circulating proteins and discovering potential intervention targets for 13 site-specific cancers

BACKGROUND

The proteome is an important reservoir of potential therapeutic targets for cancer. This study aimed to examine the causal associations between plasma proteins and cancer risk and to identify proteins with cross-cancer effects.

METHODS

Genetic instruments for 3991 plasma proteins were extracted from a large-scale proteomic study. Summary-level data of 13 site-specific cancers were derived from publicly available datasets. Proteome-wide Mendelian randomization and colocalization analyses were used to investigate the causal effect of circulating proteins on cancers. Protein-protein interactions and druggability assessment were conducted to prioritize potential therapeutic targets. Finally, systematical Mendelian randomization analysis between healthy lifestyle factors and cancer-related proteins was conducted to identify which proteins could act as interventional targets by lifestyle changes.

RESULTS

Genetically determined circulating levels of 58 proteins were statistically significantly associated with 7 site-specific cancers. A total of 39 proteins were prioritized by colocalization, of them, 11 proteins (ADPGK, CD86, CLSTN3, CSF2RA, CXCL10, GZMM, IL6R, NCR3, SIGLEC5, SIGLEC14, and TAPBP) were observed to have cross-cancer effects. Notably, 5 of these identified proteins (CD86, CSF2RA, CXCL10, IL6R, and TAPBP) have been targeted for drug development in cancer therapy; 8 proteins (ADPGK, CD86, CXCL10, GZMM, IL6R, SIGLEC5, SIGLEC14, TAPBP) could be modulated by healthy lifestyles.

CONCLUSION

Our study identified 39 circulating protein biomarkers with convincing causal evidence for 7 site-specific cancers, with 11 proteins demonstrating cross-cancer effects, and prioritized the proteins as potential intervention targets by either drugs or lifestyle changes, which provided new insights into the etiology, prevention, and treatment of cancers.

MAIT Cells Modulate Innate Immune Cells and Inhibit Colon Cancer Growth

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that can be activated by microbial antigens and cytokines and are abundant in mucosal tissues including the colon. MAIT cells have cytotoxic and pro-inflammatory functions and have potentials for use as adoptive cell therapy. However, studies into their anti-cancer activity, including their role in colon cancer, are limited. Using an animal model of colon cancer, we show that peritumoral injection of in vivo-expanded MAIT cells into RAG1-/- mice with MC38-derived tumors inhibits tumor growth compared to control. Multiplex cytokine analyses show that tumors from the MAIT cell-treated group have higher expression of markers for eosinophil-activating cytokines, suggesting an association between eosinophil recruitment and tumor inhibition. In a human peripheral leukocyte co-culture model, we show that leukocytes stimulated with MAIT ligand show an increase in eotaxin-1 production and activation of eosinophils, associated with increased cancer cell killing. In conclusion, we show that MAIT cells have a protective role in a murine colon cancer model, associated with modulation of the immune response to cancer, potentially involving eosinophil-associated mechanisms. Our results highlight the potential of MAIT cells for non-donor restricted colon cancer immunotherapy.

The Mechanistic Target of Rapamycin Complex 1 Pathway Contributes to the Anti-Tumor Effect of Granulocyte-Macrophage-Colony-Stimulating Factor-Producing T Helper Cells in Mouse Colorectal Cancer

INTRODUCTION

The role of granulocyte-macrophage-colony-stimulating factor-producing T helper (ThGM) cells in colorectal cancer (CRC) development remains unclear. This study characterizes the function of ThGM cells in mouse CRC.

METHODS

Mouse CRC was induced by administrating azoxymethane and dextran sulfate sodium. The presence of ThGM cells in CRC tissues and the mechanistic target of rapamycin complex 1 (mTORC1) signaling in ThGM cells was detected by flow cytometry. The impact of mTORC1 signaling on ThGM cell function was determined by in vitro culture. The effect of ThGM cells on CRC development was evaluated by adoptive transfer assays.

RESULTS

ThGM cells, which expressed granulocyte-macrophage-colony-stimulating factor (GM-CSF), accumulated in CRC tissues. mTORC1 signaling is activated in CRC ThGM cells. mTORC1 inhibition by rapamycin suppressed ThGM cell differentiation and proliferation and resulted in the death of differentiating ThGM cells. mTORC1 inhibition in already differentiated ThGM cells did not induce significant cell death but decreased the expression of GM-CSF, interleukin-2, and tumor necrosis factor-alpha while impeding cell proliferation. Furthermore, mTORC1 inhibition diminished the effect of ThGM cells on driving macrophage polarization toward the M1 type, as evidenced by lower expression of pro-inflammatory cytokines, major histocompatibility complex class II molecule, and CD80 in macrophages after co-culture with rapamycin-treated ThGM cells. Lentivirus-mediated knockdown/overexpression of regulatory-associated protein of mTOR (Raptor) confirmed the essential role of mTORC1 in ThGM cell differentiation and function. Adoptively transferred ThGM cells suppressed CRC growth whereas mTORC1 inhibition abolished this effect.

CONCLUSION

mTORC1 is essential for the anti-CRC activity of ThGM cells.

Identification of novel protein biomarkers and drug targets for colorectal cancer by integrating human plasma proteome with genome

BACKGROUND

The proteome is a major source of therapeutic targets. We conducted a proteome-wide Mendelian randomization (MR) study to identify candidate protein markers and therapeutic targets for colorectal cancer (CRC).

METHODS

Protein quantitative trait loci (pQTLs) were derived from seven published genome-wide association studies (GWASs) on plasma proteome, and summary-level data were extracted for 4853 circulating protein markers. Genetic associations with CRC were obtained from a large-scale GWAS meta-analysis (16,871 cases and 26,328 controls), the FinnGen cohort (4957 cases and 304,197 controls), and the UK Biobank (9276 cases and 477,069 controls). Colocalization and summary-data-based MR (SMR) analyses were performed sequentially to verify the causal role of candidate proteins. Single cell-type expression analysis, protein-protein interaction (PPI), and druggability evaluation were further conducted to detect the specific cell type with enrichment expression and prioritize potential therapeutic targets.

RESULTS

Collectively, genetically predicted levels of 13 proteins were associated with CRC risk. Elevated levels of two proteins (GREM1, CHRDL2) and decreased levels of 11 proteins were associated with an increased risk of CRC, among which four (GREM1, CLSTN3, CSF2RA, CD86) were prioritized with the most convincing evidence. These protein-coding genes are mainly expressed in tissue stem cells, epithelial cells, and monocytes in colon tumor tissue. Two interactive pairs of proteins (GREM1 and CHRDL2; MMP2 and TIMP2) were identified to be involved in osteoclast differentiation and tumorigenesis pathways; four proteins (POLR2F, CSF2RA, CD86, MMP2) have been targeted for drug development on autoimmune diseases and other cancers, with the potentials of being repurposed as therapeutic targets for CRC.

CONCLUSIONS

This study identified several protein biomarkers to be associated with CRC risk and provided new insights into the etiology and promising targets for the development of screening biomarkers and therapeutic drugs for CRC.

X-ray-Guided In Situ Genetic Engineering of Macrophages for Sustained Cancer Immunotherapy

Effective repolarization of macrophages has emerged as a promising approach for anticancer therapy. However, there are very few studies on the effect of reprogramming macrophages from M2 phenotype to M1 phenotype without reconversion while maintaining an activated M1 phenotype. Moreover, these immunomodulatory methods have serious drawbacks due to the activation of normal monocytic cells. Therefore, it remains a challenge to selectively reprogram tumor-associated macrophages (TAMs) without systemic toxicities. Here, X-ray-guided and triggered remote control of a CRISPR/Cas9 genome editing system (X-CC9) that exclusively activates therapeutic agents at tumor sites is established. Under X-ray irradiation, X-CC9 selectively enhances M2-to-M1 repolarization within the tumor microenvironment, and significantly improves antitumor efficacy with robust immune responses in two animal models. This strategy provides an ideal method for improving the safety of macrophage polarization and may constitute a promising immunotherapy strategy.

Tumor-associated macrophages employ immunoediting mechanisms in colorectal tumor progression: Current research in Macrophage repolarization immunotherapy

Tumor-associated macrophages (TAMs) constitute the most prolific resident of the tumor microenvironment (TME) that regulate its TME into tumor suppressive or progressive milieu by utilizing immunoediting machinery. Here, the tumor cells construct an immunosuppressive microenvironment that educates TAMs to polarize from anti-tumor TAM-M1 to pro-tumor TAM-M2 phenotype consequently contributing to tumor progression. In colorectal cancer (CRC), the TME displays a prominent pro-tumorigenic immune profile with elevated expression of immune-checkpoint molecules notably PD-1, CTLA4, etc., in both MSI and ultra-mutated MSS tumors. This authenticated immune-checkpoint inhibition (ICI) immunotherapy as a pre-requisite for clinical benefit in CRC. However, in response to ICI, specifically, the MSI^hi tumors evolved to produce novel immune escape variants thus undermining ICI. Lately, TAM-directed therapies extending from macrophage depletion to repolarization have enabled TME alteration. While TAM accrual implicates clinical benefit in CRC, sustained inflammatory insult may program TAMs to shift from M1 to M2 phenotype. Their ability to oscillate on both facets of the spectrum represents macrophage repolarization immunotherapy as an effective approach to treating CRC. In this review, we briefly discuss the differentiation heterogeneity of colonic macrophages that partake in macrophage-directed immunoediting mechanisms in CRC progression and its employment in macrophage re-polarization immunotherapy.

Granulocyte-macrophage colony stimulating factor enhances efficacy of nimustine rendezvousing with temozolomide plus irradiation in patients with glioblastoma

BACKGROUND

Glioblastoma is the most common and most aggressive type of primary brain tumor.

OBJECTIVE

The aim of this study was to investigate the efficacy and safety of intranasal granulocyte-macrophage colony stimulating factor (GM-CSF) administration combined with chemoradiotherapy in patients with glioblastoma who underwent surgery.

METHODS

Ninety-two patients were randomly divided into two groups: a control group (n= 46), who received radiotherapy with adjuvant local delivery of nimustine hydrochloride (ACNU) and systemic administration of temozolomide, and an intervention group (n= 46), who received intranasal GM-CSF prior to each cycle of adjuvant chemotherapy in addition to the treatment of the control group. Karnofsky performance status (KPS) scores, progression-free survival (PFS), overall survival (OS), and adverse effects were calculated and compared between the two groups.

RESULTS

Compared with the control group, the intervention group had longer PFS (7.8 vs. 6.9 months, P= 0.016) and OS (19.2 vs. 17.1 months, P= 0.045, without adjustment for interim analyses). The KPS scores were also higher in the intervention group than in the control group after 6 months (84.35 ± 8.86 vs. 80.65 ± 7.72; t= 4.552, P= 0.036). Furthermore, the patients in the intervention group had lower incidence of neutropenia and thrombocytopenia (8.7% vs. 29.5%, P= 0.012; 8.7% vs. 18.2%, P= 0.186). Other adverse events were similar in both groups, and most adverse events were grade I/II and resolved spontaneously.

CONCLUSION

Intranasal GM-CSF enhances the efficacy of the local ACNU administration combined with oral temozolomide chemotherapy. The survival and performance status were significantly improved in patients with glioblastoma after surgery. Additionally, the GM-CSF therapy was able to reduce the occurrence of chemotherapy-related neutropenia and thrombocytopenia.

Dense GM-CSFRα-expressing immune infiltration is allied with longer survival of intrahepatic cholangiocarcinoma patients

Background

Intrahepatic cholangiocarcinoma (iCCA) is a cancer arising from intrahepatic bile duct epithelium. An iCCA incidence is increasing worldwide; however, the outcome of the disease is dismal. The linkage between chronic inflammation and iCCA progression is well established, but the roles of granulocyte-macrophage colony-stimulating factor (GM-CSF) remain unrevealed. Thus, a better understanding of GM-CSF functions in CCA may provide an alternative approach to CCA treatment.

Methods

Differential GM-CSF and GM-CSFRα mRNA expressions in CCA tissues were investigated by Gene Expression Profiling Interactive Analysis (GEPIA) based on The Cancer Genome Atlas (TCGA) database. The protein expressions and localizations of GM-CSF and its cognate receptor (GM-CSFRα) in iCCA patients' tissues were demonstrated by the immunohistochemistry (IHC) techniques. The survival analyses were performed using Kaplan-Meier survival analysis with log-rank test and Cox proportional hazard regression model for multivariate analysis. The GM-CSF productions and GM-CSFRα expressions on CCA cells were assessed by ELISA and flow cytometry. The effects of GM-CSF on CCA cell proliferation and migration were evaluated after recombinant human GM-CSF treatment. The relationship between GM-CSF or GM-CSFRα level and related immune cell infiltration was analyzed using the Tumor Immune Estimation Resource (TIMER).

Results

GEPIA analysis indicated GM-CSF and GM-CSFRα expressions were higher in CCA tissues than in normal counterparts, and high GM-CSFRα was related to the longer disease-free survival of the patients (p < 0.001). IHC analysis revealed that CCA cells differentially expressed GM-CSF, while GM-CSFRα was expressed on cancer-infiltrating immune cells. The patient whose CCA tissue contained high GM-CSF expressed CCA, and moderate to dense GM-CSFRα-expressing immune cell infiltration (ICI) acquired longer overall survival (OS) (p = 0.047), whereas light GM-CSFRα-expressing ICI contributed to an increased hazard ratio (HR) to 1.882 (95% CI [1.077-3.287]; p = 0.026). In non-papillary subtype, an aggressive CCA subtype, patients with light GM-CSFRα-expressing ICI had shorter median OS (181 vs. 351 days; p = 0.002) and the HR was elevated to 2.788 (95% CI [1.299-5.985]; p = 0.009). Additionally, TIMER analysis demonstrated GM-CSFRα expression was positively correlated with neutrophil, dendritic cell, and CD8+ T cell infiltrations, though it was conversely related to M2-macrophage and myeloid-derived suppressor cell infiltration. However, the direct effects of GM-CSF on CCA cell proliferation and migration were not observed in the current study.

Conclusions

Light GM-CSFRα-expressing ICI was an independent poor prognostic factor for iCCA patients. Anti-cancer functions of GM-CSFRα-expressing ICI were suggested. Altogether, the benefits of acquired GM-CSFRα-expressing ICI and GM-CSF for CCA treatment are proposed herein and require elucidation.

GM-CSF: A Double-Edged Sword in Cancer Immunotherapy

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that drives the generation of myeloid cell subsets including neutrophils, monocytes, macrophages, and dendritic cells in response to stress, infections, and cancers. By modulating the functions of innate immune cells that serve as a bridge to activate adaptive immune responses, GM-CSF globally impacts host immune surveillance under pathologic conditions. As with other soluble mediators of immunity, too much or too little GM-CSF has been found to promote cancer aggressiveness. While too little GM-CSF prevents the appropriate production of innate immune cells and subsequent activation of adaptive anti-cancer immune responses, too much of GM-CSF can exhaust immune cells and promote cancer growth. The consequences of GM-CSF signaling in cancer progression are a function of the levels of GM-CSF, the cancer type, and the tumor microenvironment. In this review, we first discuss the secretion of GM-CSF, signaling downstream of the GM-CSF receptor, and GM-CSF’s role in modulating myeloid cell homeostasis. We then outline GM-CSF’s anti-tumorigenic and pro-tumorigenic effects both on the malignant cells and on the non-malignant immune and other cells in the tumor microenvironment. We provide examples of current clinical and preclinical strategies that harness GM-CSF’s anti-cancer potential while minimizing its deleterious effects. We describe the challenges in achieving the Goldilocks effect during administration of GM-CSF-based therapies to patients with cancer. Finally, we provide insights into how technologies that map the immune microenvironment spatially and temporally may be leveraged to intelligently harness GM-CSF for treatment of malignancies.

Molecular Mechanisms of Tumor Immunomodulation in the Microenvironment of Colorectal Cancer

Colorectal cancer remains one of the most important health challenges in our society. The development of cancer immunotherapies has fostered the need to better understand the anti-tumor immune mechanisms at play in the tumor microenvironment and the strategies by which the tumor escapes them. In this review, we provide an overview of the molecular interactions that regulate tumor inflammation. We particularly discuss immunomodulatory cell-cell interactions, cell-soluble factor interactions, cell-extracellular matrix interactions and cell-microbiome interactions. While doing so, we highlight relevant examples of tumor immunomodulation in colorectal cancer.

Lipid-Laden Macrophages and Inflammation in Atherosclerosis and Cancer: An Integrative View

Atherosclerotic arterial plaques and malignant solid tumors contain macrophages, which participate in anaerobic metabolism, acidosis, and inflammatory processes inherent in the development of either disease. The tissue-resident macrophage populations originate from precursor cells derived from the yolk sac and from circulating bone marrow-derived monocytes. In the tissues, they differentiate into varying functional phenotypes in response to local microenvironmental stimulation. Broadly categorized, the macrophages are activated to polarize into proinflammatory M1 and anti-inflammatory M2 phenotypes; yet, noticeable plasticity allows them to dynamically shift between several distinct functional subtypes. In atherosclerosis, low-density lipoprotein (LDL)-derived cholesterol accumulates within macrophages as cytoplasmic lipid droplets thereby generating macrophage foam cells, which are involved in all steps of atherosclerosis. The conversion of macrophages into foam cells may suppress the expression of given proinflammatory genes and thereby initiate their transcriptional reprogramming toward an anti-inflammatory phenotype. In this particular sense, foam cell formation can be considered anti-atherogenic. The tumor-associated macrophages (TAMs) may become polarized into anti-tumoral M1 and pro-tumoral M2 phenotypes. Mechanistically, the TAMs can regulate the survival and proliferation of the surrounding cancer cells and participate in various aspects of tumor formation, progression, and metastasis. The TAMs may accumulate lipids, but their type and their specific roles in tumorigenesis are still poorly understood. Here, we discuss how the phenotypic and functional plasticity of macrophages allows their multifunctional response to the distinct microenvironments in developing atherosclerotic lesions and in developing malignant tumors. We also discuss how the inflammatory reactions of the macrophages may influence the development of atherosclerotic plaques and malignant tumors, and highlight the potential therapeutic effects of targeting lipid-laden macrophages in either disease.

Systemic Interleukins' Profile in Early and Advanced Colorectal Cancer

Tumor microenvironment (TME) is characterized by mutual interactions of the tumor, stromal and immune cells. Early and advanced colorectal tumors differ in structure and present altered serum cytokine levels. Mutual crosstalk among TME infiltrating cells may shift the balance into immune suppressive or pro-inflammatory, antitumor response this way influencing patients' prognosis. Cancer-related inflammation affects all the body and this way, the systemic level of cytokines could reflect TME processes. Despite numerous studies, it is still not known how systemic cytokines levels change during colorectal cancer (CRC) tumor development. Better understanding tumor microenvironment processes could help in planning therapeutic interventions and more accurate patient prognosis. To contribute to the comprehension of these processes within TME, we reviewed cytokines levels from clinical trials in early and advanced colorectal cancer. Presented data were analyzed in the context of experimental studies and studies analyzing tumor infiltration with immune cells. The review summarizes clinical data of cytokines secreted by tumor microenvironment cells: lymphocytes T helper 1 (Th1), lymphocytes T helper 2 (Th2), lymphocytes T helper 17 (Th17), regulatory T cells (Treg cells), regulatory T cells (Breg cells), M1/M2 macrophages, N1/N2 neutrophils, myeloid-derived suppressor cells (MDSC), dendritic cells (DC), innate lymphoid cells (ILC) natural killer (NK) cells and tumor cells.

GM-CSF Nitration Is a New Driver of Myeloid Suppressor Cell Activity in Tumors

Reactive oxygen species, including RNS, contribute to the control of multiple immune cell functions within the tumor microenvironment (TME). Tumor-infiltrating myeloid cells (TIMs) represent the archetype of tolerogenic cells that actively contribute to dismantle effective immunity against cancer. TIMs inhibit T cell functions and promote tumor progression by several mechanisms including the amplification of the oxidative/nitrosative stress within the TME. In tumors, TIM expansion and differentiation is regulated by the granulocyte-macrophage colony-stimulating factor (GM-CSF), which is produced by cancer and immune cells. Nevertheless, the role of GM-CSF in tumors has not yet been fully elucidated. In this study, we show that GM-CSF activity is significantly affected by RNS-triggered post-translational modifications. The nitration of a single tryptophan residue in the sequence of GM-CSF nourishes the expansion of highly immunosuppressive myeloid subsets in tumor-bearing hosts. Importantly, tumors from colorectal cancer patients express higher levels of nitrated tryptophan compared to non-neoplastic tissues. Collectively, our data identify a novel and selective target that can be exploited to remodel the TME and foster protective immunity against cancer.

Step-by-Step Immune Activation for Suicide Gene Therapy Reinforcement

Gene-directed enzyme prodrug gene therapy (GDEPT) theoretically represents a useful method to carry out chemotherapy for cancer with minimal side effects through the formation of a chemotherapeutic agent inside cancer cells. However, despite great efforts, promising preliminary results, and a long period of time (over 25 years) since the first mention of this method, GDEPT has not yet reached the clinic. There is a growing consensus that optimal cancer therapies should generate robust tumor-specific immune responses. The advent of checkpoint immunotherapy has yielded new highly promising avenues of study in cancer therapy. For such therapy, it seems reasonable to use combinations of different immunomodulators alongside traditional methods, such as chemotherapy and radiotherapy, as well as GDEPT. In this review, we focused on non-viral gene immunotherapy systems combining the intratumoral production of toxins diffused by GDEPT and immunomodulatory molecules. Special attention was paid to the applications and mechanisms of action of the granulocyte-macrophage colony-stimulating factor (GM–CSF), a cytokine that is widely used but shows contradictory effects. Another method to enhance the formation of stable immune responses in a tumor, the use of danger signals, is also discussed. The process of dying from GDEPT cancer cells initiates danger signaling by releasing damage-associated molecular patterns (DAMPs) that exert immature dendritic cells by increasing antigen uptake, maturation, and antigen presentation to cytotoxic T-lymphocytes. We hypothesized that the combined action of this danger signal and GM–CSF issued from the same dying cancer cell within a limited space would focus on a limited pool of immature dendritic cells, thus acting synergistically and enhancing their maturation and cytotoxic T-lymphocyte attraction potential. We also discuss the problem of enhancing the cancer specificity of the combined GDEPT–GM–CSF–danger signal system by means of artificial cancer specific promoters or a modified delivery system.

Tumor mutation burden in blood predicts benefit from neoadjuvant chemo/radiotherapy in locally advanced rectal cancer

Distant metastasis has been the major concern of prognosis in patients with locally advanced rectal cancer (LARC). The purpose of this study was to investigate the prognostic value of TMB in blood (bTMB) in LARC patients after receiving neoadjuvant chemoradiotherapy (nCRT) and surgery. Using targeted ctDNA sequencing, we revealed that bTMB level at baseline was positively correlated with recurrence-free survival (RFS). Following nCRT, the patients with decreasing TMB tends to have a longer median RFS. bTMB level after surgery was negatively correlated with RFS. The serum cytokines including IFNγ, IFNα2, IL-1β, IL-2 and MIP-1β were significantly higher in pre-nCRT serum with higher bTMB group than that of lower bTMB group. Clonal evolution analysis showed that the pre- and post-nCRT ctDNAs of most cases had shared mutations. In conclusion, we presume that bTMB could potentially improve pre- and post-treatment risk assessment and facilitate individualized therapy for patients with LARC.

In vivo vaccination with cell line-derived whole tumor lysates: neoantigen quality, not quantity matters

BACKGROUND

Cancer vaccines provide a complex source of neoantigens. Still, increasing evidence reveals that the neoantigen quality rather than the quantity is predictive for treatment outcome.

METHODS

Using the preclinical Mlh1^-/- tumor model, we performed a side-by side comparison of two autologous cell-line derived tumor lysates (namely 328 and A7450 T1 M1) harboring different tumor mutational burden (TMB; i.e. ultra-high: 328; moderate-high: A7450 T1 M1). Mice received repetitive prophylactic or therapeutic applications of the vaccine. Tumor incidence, immune responses and tumor microenvironment was examined.

RESULTS

Both tumor cell lysates delayed tumor formation in the prophylactic setting, with the A7450 T1 M1 lysate being more effective in decelerating tumor growth than the 328 lysate (median overall survival: 37 vs. 25 weeks). Comparable results were achieved in therapeutic setting and could be traced back to antigen-driven immune stimulation. Reactive T cells isolated from A7450 T1 M1-treated mice recognized autologous Mlh1^-/- tumor cells in IFNγ ELISpot, but likewise YAC-1 cells, indicative for stimulation of both arms of the immune system. By deciphering local effects, vaccines shaped the tumor microenvironment differently. While A7450 T1 M1 prophylactically vaccinated tumors harbored low numbers of myeloid-derived suppressor cells (MDSC) and elevated CD8-T cell infiltrates, vaccination with the 328 lysate evoked MDSC infiltration. Similar effects were seen in the therapeutic setting with stable disease induction only upon A7450 T1 M1 vaccination. Untangling individual response profiles revealed strong infiltration with LAG3⁺ and PD-L1⁺ immune cells when treatments failed, but almost complete exclusion of checkpoint-expressing lymphocytes in long-term survivors.

CONCLUSIONS

By applying two tumor cell lysates we demonstrate that neoantigen quality outranks quantity. This should be considered prior to designing cancer vaccine-based combination approaches.

Genomic analysis of the prognostic value of colony-stimulating factors (CSFs) and colony-stimulating factor receptors (CSFRs) across 24 solid cancer types

Background

The prognostic roles of granulocyte-/granulocyte-macrophage colony-stimulating factor (G-/GM-CSF) and its receptors (CSFRs) from the genomic perspective remain controversial. The aim of our study was to evaluate their prognostic value in multiple cancer types by analyzing omics data.

Methods

The omics data of G-/GM-CSF and receptors were obtained from the cBioportal database. Cutoff values were determined by X-tile. Overall survival (OS) was assessed by Kaplan–Meier curves. Differentially expressed genes (DEGs) and common regulated genes were analyzed using R software and Venny 2.1.0, while enrichment pathway analyses were performed by Metascape.

Results

A comprehensive mRNA analysis was performed in 8,565 patients across 24 cancer types. The combination subgroup of CSF2 and its receptors with high expression and favorable prognosis was associated with the activation of immune-related pathways, while the subgroup with unfavorable prognosis was associated with the activation of inflammatory and cellular pathways. As for the combination subgroup of CSF3 and its receptor, the high expression and poor prognosis subgroup was accompanied by the activation of inflammation and signaling transduction pathways.

Conclusions

The prognostic value of CSFs and CSFRs are cancer-type dependent. Therefore, personalized risk stratification based on CSF and CSFR pathway should be considered for cancer patients.

Tumor-associated macrophage infiltration and prognosis in colorectal cancer: systematic review and meta-analysis

BACKGROUND

Tumor-associated macrophages (TAMs) are key components of colorectal cancer (CRC) microenvironment, but their role in CRC prognosis is not fully defined.

OBJECTIVE

This study aimed to evaluate prognostic value of different types and distribution of TAMs in CRC.

METHODS

Total 27 studies with 6115 patients were searched from PubMed and Embase and analyzed to determine the association between TAMs, including distinct TAM subsets and infiltration location, and CRC survival. The prognostic impact of TAMs on CRC was further stratified by tumor type and mismatch repair system (MMR) status.

RESULTS

A pooled analysis indicated that high density of TAMs in CRC tissue was significantly associated with favorable 5-year overall survival (OS) but not with disease-free survival (DFS). CD 68⁺ TAM subset correlated with better 5-year OS, while neither CD68⁺NOS2⁺ M1 subset nor CD163⁺ M2 subset was correlated with 5-year OS. Increased CD68⁺ TAM infiltration in tumor stroma but not in tumor islet predicted improved 5-year OS. Stratification by tumor type and MMR status showed that in colon cancer or MMR-proficient CRC, elevated TAM density was associated with better 5-year OS.

CONCLUSIONS

High infiltration of CD68⁺ TAMs could be a favorable prognostic marker in CRC. Future therapies stimulating CD68⁺ TAM infiltration may be promising in CRC treatment.

The role of Candida albicans candidalysin ECE1 gene in oral carcinogenesis

Oral squamous cell carcinoma is associated with many known risk factors including tobacco smoking, chronic alcoholism, poor oral hygiene, unhealthy dietary habits and microbial infection. Previous studies have highlighted Candida albicans host tissue infection as a risk factor in the initiation and progression of oral cancer. C albicans invasion induces several cancerous hallmarks, such as activation of proto-oncogenes, induction of DNA damage and overexpression of inflammatory signalling pathways. However, the molecular mechanisms behind these responses remain unclear. A recently discovered fungal toxin peptide, candidalysin, has been reported as an essential molecule in epithelial damage and host recognition of C albicans infection. Candidalysin has a clear role in inflammasome activation and induction of cell damage. Several inflammatory molecules such as IL-6, IL-17, NLRP3 and GM-CSF have been linked to carcinogenesis. Candidalysin is encoded by the ECE1 gene, which has been linked to virulence factors of C albicans such as adhesion, biofilm formation and filamentation properties. This review discusses the recent epidemiological burden of oral cancer and highlights the significance of the ECE1 gene and the ECE1 protein breakdown product, candidalysin in oral malignancy. The immunological and molecular mechanisms behind oral malignancy induced by inflammation and the role of the toxic fungal peptide candidalysin in oral carcinogenesis are explored. With increasing evidence associating C albicans with oral carcinoma, identifying the possible fungal pathogenicity factors including the role of candidalysin can assist in efforts to understand the link between C albicans infection and carcinogenesis, and pave the way for research into therapeutic potentials.

Quantitative Proteome Responses to Oncolytic Reovirus in GM-CSF- and M-CSF-Differentiated Bone Marrow-Derived Cells

The efficacy of oncolytic viruses (OVs), such as reovirus, is dictated by host immune responses, including those mediated by the pro- versus anti-inflammatory macrophages. As such, a detailed understanding of the interaction between reovirus and different macrophage types is critical for therapeutic efficacy. To explore reovirus-macrophage interactions, we performed tandem mass tag (TMT)-based quantitative temporal proteomics on mouse bone marrow-derived macrophages (BMMs) generated with two cytokines, macrophage colony stimulating factor (M-CSF) and granulocytic-macrophage colony stimulating factor (GM-CSF), representing anti- and proinflammatory macrophages, respectively. We quantified 6863 proteins across five time points in duplicate, comparing M-CSF (M-BMM) and GM-CSF (GM-BMM) in response to OV. We find that GM-BMMs have lower expression of key intrinsic proteins that facilitate an antiviral immune response, express higher levels of reovirus receptor protein JAM-A, and are more susceptible to oncolytic reovirus infection compared to M-BMMs. Interestingly, although M-BMMs are less susceptible to reovirus infection and subsequent cell death, they initiate an antireovirus adaptive T cell immune response comparable to that of GM-BMMs. Taken together, these data describe distinct proteome differences between these two macrophage populations in terms of their ability to mount antiviral immune responses.

Premetastatic niches, exosomes and circulating tumor cells: Early mechanisms of tumor dissemination and the relation to surgery

The physiological stress response to surgery promotes wound healing and functional recovery and includes the activation of neural, inflammatory and proangiogenic signaling pathways. Paradoxically, the same pathways also promote metastatic spread and growth of residual cancer. Human and animal studies show that cancer surgery can increase survival, migration and proliferation of residual tumor cells. To secure the survival and growth of disseminated tumor cells, the formation of premetastatic niches in target organs involves a complex interplay between microenvironment, immune system, circulating tumor cells, as well as chemical mediators and exosomes secreted by the primary tumor. This review describes the current understanding of the early mechanisms of dissemination, as well as how surgery may facilitate disease progression.

Efficacy of early combination of local radiotherapy and GM-CSF for advanced non-small cell lung cancer treated with icotinib

BACKGROUND

Lung cancer is a disease that severely endangers human health. Non-small cell lung cancer (NSCLC) accounts for approximately 4/5 of lung cancers.

AIMS

To investigate the efficacy of early combination of local radiotherapy and granulocyte macrophage colony-stimulating factor (GM-CSF) for advanced NSCLC treated with icotinib.

METHODS

Forty-two patients with stage IV NSCLC complicated with EGFR gene mutation were selected and randomly divided into two groups, with 21 patients in each group. Patients in control group were treated with icotinib, and patients in experimental group were treated with icotinib combined with local radiotherapy and subcutaneous injection of GM-CSF. One-year progression free survival between two groups was compared.

RESULTS

Three months after treatment, the efficacy in experimental group was significantly better than that in control group, and objective response rate was 95.24% in experimental group, which was higher than the 71.43% in control group. Patients in experimental group had no differences in white blood cell and neutrophil, but had significantly lower carcino-embryonic antigen and neuron-specific enolase levels and higher CD3+, CD4+, and CD4+/CD8+ than those in control group and before treatment. There were no differences in the proportion of patients with adverse reactions between two groups. One-year progression free survival was significantly better in experimental group than in control group.

CONCLUSIONS

Early combination of local radiotherapy and GM-CSF has a significant efficacy for advanced NSCLC accounts for approximately 4/5 of lung cancers treated with icotinib, and it can improve patients' autoimmunity and lengthen progression free survival.

Oncolytic Viruses for Cancer Therapy: Barriers and Recent Advances

Oncolytic viruses (OVs) are powerful new therapeutic agents in cancer therapy. With the first OV (talimogene laherparepvec [T-vec]) obtaining US Food and Drug Administration approval, interest in OVs has been boosted greatly. Nevertheless, despite extensive research, oncolytic virotherapy has shown limited efficacy against solid tumors. Recent advances in viral retargeting, genetic editing, viral delivery platforms, tracking strategies, OV-based gene therapy, and combination strategies have the potential to broaden the applications of oncolytic virotherapy in oncology. In this review, we present several insights into the limitations and challenges of oncolytic virotherapy, describe the strategies mentioned above, provide a summary of recent preclinical and clinical trials in the field of oncolytic virotherapy, and highlight the need to optimize current strategies to improve clinical outcomes.

Systemic inflammation in colorectal cancer: Underlying factors, effects, and prognostic significance

Systemic inflammation is a marker of poor prognosis preoperatively present in around 20%-40% of colorectal cancer patients. The hallmarks of systemic inflammation include an increased production of proinflammatory cytokines and acute phase proteins that enter the circulation. While the low-level systemic inflammation is often clinically silent, its consequences are many and may ultimately lead to chronic cancer-associated wasting, cachexia. In this review, we discuss the pathogenesis of cancer-related systemic inflammation, explore the role of systemic inflammation in promoting cancer growth, escaping antitumor defense, and shifting metabolic pathways, and how these changes are related to less favorable outcome.

A replication-incompetent CD154/40L recombinant vaccinia virus induces direct and macrophage-mediated antitumor effects in vitro and in vivo

CD40 triggering may result in antitumor effects of potentially high clinical relevance. To gain insights important for patient selection and to identify adequate targeting techniques, we investigated CD40 expression in human cancer tissues and generated a replication-incompetent recombinant vaccinia virus expressing CD40 ligand (rVV40L). Its effects were explored in vitro and in vivo upon direct CD40 targeting on malignant cells or macrophage activation. CD40 expression was analyzed by immunohistochemistry in tumor and stromal cells in a multi-tumor array including 836 specimens from 27 different tumor types. Established tumor cell lines were used to explore the capacity of rVV40L to induce malignant cell apoptosis and modulate functional profiles of polarized macrophages. CD40 expression was detectable in significantly higher numbers of stromal as compared to malignant cells in lung and breast cancers. CD40 ligation following rVV40L infection induced apoptosis in CD40(+) cancer cells, but only in the presence of intact specific signal transduction chain. Importantly, rVV40L infection promoted the induction of TNF-α-dependent antitumor activity of M1-like macrophages directed against CD40(-) targets. CD40-activated M1-like macrophages also displayed enhanced ability to CXCL10-dependently recruit CD8+ T cells and to efficiently present cancer cell intracellular antigens through cross-priming. Moreover, rVV-driven CD40L expression partially “re-educated” M2-like macrophages, as suggested by detectable CXCL10 and IL-12 production. Most importantly, we observed that intra-tumoral injection of rVV40L-infected human macrophages inhibits progression of human CD40(-) tumors in vivo. First evidences of anticancer activity of rVV40L strongly encourage further evaluations.

Colony-stimulating factors detected in tumor cells and voided urine are potential prognostic markers for patients with muscle-invasive bladder cancer undergoing radical cystectomy

Background

The clinical use of macrophage colony-stimulating factor, granulocyte colony-stimulating factor (G-CSF), and granulocyte macrophage colony-stimulating factor (GM-CSF) has improved the safety of cytotoxic chemotherapy. However, the overexpression of these CSFs in cancers has been reported to be associated with a poor prognosis in various malignancies. We evaluated the potential of CSF expression as a predictor of clinical outcome in patients with muscle-invasive bladder cancer (MIBC).

Methods

Consecutive patients (n=58) with MIBC who underwent radical cystectomy (RC) were included in this retrospective study. Treatment-naïve tumor specimens obtained by initial transurethral resection of bladder tumors prior to RC were immunostained with antibodies against macrophage colony-stimulating factor, G-CSF, and GM-CSF. We compared the clinicopathological variables and survival between these groups. Baseline levels of CSFs in the serum and voided urine were quantified using an enzyme-linked immunosorbent assay and compared with the expression of CSFs in the tumor lesions.

Results

Low expression of GM-CSF in the tumor cells was significantly correlated with a pathological T4 category (vs T2–3; P=0.02). In univariate survival analysis, high G-CSF and low GM-CSF expression in the tumor lesion were associated with poor outcomes. Furthermore, Cox proportional regression analysis revealed that high G-CSF and low GM-CSF expression in the tumor were independent predictors of shorter recurrence-free survival, cancer-specific survival, and overall survival. The levels of CSFs in voided urine were associated with the expression of CSFs in the tumor lesions.

Conclusion

GM-CSF and G-CSF expression in the tumor lesions obtained by initial transurethral resection are independent predictors of poor outcome in MIBC after RC. Levels of G-CSF and GM-CSF in urine before treatment could be useful in prognostication.

PKCα in colon cancer cells promotes M1 macrophage polarization via MKK3/6-P38 MAPK pathway

Tumor associated macrophages are potential targets of the immune therapy for patients with colon cancer. PKCα acts as a tumor suppressor in the intestine. However, the correlation between PKCα expressed in colon cancer cells and tumor associated macrophages polarization has never been detected. In the present study, the correlation between PKCα expression and level of M1 macrophages was evaluated in human colon cancer tissues. A xenograft mouse model of colon cancer cells with different PKCα expression level was constructed to evaluate the effect of PKCα on M1 macrophages polarization in vivo. Co-culture of colon cancer cells and differentiated macrophages was used to detect the potential interplay in vitro. PKCα regulated production of cytokines which correlated with macrophage polarization and the underlying mechanism was further explored. Our study showed that high PKCα expression in human colon cancer tissues correlated with better prognosis and high M1 macrophage content. PKCα expressed in colon cancer cells inhibited the growth of colon cancer in mice model. PKCα induced macrophages polarized to the M1-like phenotype both in vitro and in vivo. Mechanistically, PKCα targeted P38 via MKK3/6 to promote IL12 and GM-CSF expression which further enhanced M1-like macrophages polarization. In conclusion, this study provided evidence for the first time that PKCα in colon cancer cells play an anticancer action by inducing the polarization of tumor associated macrophages to M1-like phenotype in the tumor microenvironment. PKCα promoted IL12/GM-CSF-mediated M1 polarization through MKK3/6-P38 signaling pathway. Our investigation suggested that modulation of the PKCα signaling pathway might serve as a novel strategy for colon cancer therapy.

Elevated serum granulocyte-macrophage colony-stimulating factor levels during radiotherapy predict favorable outcomes in lung and esophageal cancer

The combination of exogenous granulocyte-macrophage colony-stimulating factor (GM-CSF) with radiotherapy (RT) has been demonstrated to strengthen the antitumor immune response. We hypothesized that the variation of GM-CSF during RT was correlated with cancer prognosis. We measured serum levels of GM-CSF and interferon-γ (IFN-γ) before and during RT in 126 unresectable lung and esophageal cancer patients and performed survival analyses. Upregulated GM-CSF levels during RT correlated with longer overall survival (OS) and progression-free survival (PFS). On the other hand, no difference in OS or PFS was seen at different IFN-γ levels. However, the “integrated factor”, computed as the combination of high pre-RT IFN-γ levels and upregulated GM-CSF, correlated with prolonged OS and PFS. Multivariate analyses revealed that GM-CSF levels and the integrated factor were both stronger independent prognostic factors than disease stage. These data demonstrate that GM-CSF levels during RT can be used as a prognostic biomarker for lung and esophageal cancer.

Silencing of Profilin-1 suppresses cell adhesion and tumor growth via predicted alterations in integrin and Ca2+ signaling in T24M-based bladder cancer models

Bladder cancer (BC) is the second most common malignancy of the genitourinary system, characterized by the highest recurrence rate of all cancers. Treatment options are limited; thus a thorough understanding of the underlying molecular mechanisms is needed to guide the discovery of novel therapeutic targets. Profilins are actin binding proteins with attributed pleiotropic functions to cytoskeletal remodeling, cell adhesion, motility, even transcriptional regulation, not fully characterized yet. Earlier studies from our laboratory revealed that decreased tissue levels of Profilin-1 (PFN1) are correlated with BC progression to muscle invasive disease. Herein, we describe a comprehensive analysis of PFN1 silencing via shRNA, in vitro (by employing T24M cells) and in vivo [(with T24M xenografts in non-obese diabetic severe combined immunodeficient mice (NOD/SCID) mice]. A combination of phenotypic and molecular assays, including migration, proliferation, adhesion assays, flow cytometry and total mRNA sequencing, as well as immunohistochemistry for investigation of selected findings in human specimens were applied. A decrease in BC cell adhesion and tumor growth in vivo following PFN downregulation are observed, likely associated with the concomitant downregulation of Fibronectin receptor, Endothelin-1, and Actin polymerization. A decrease in the levels of multiple key members of the non-canonical Wnt/Ca²⁺ signaling pathway is also detected following PFN1 suppression, providing the groundwork for future studies, addressing the specific role of PFN1 in Ca²⁺ signaling, particularly in the muscle invasive disease.

Defining Genome-Wide Expression and Phenotypic Contextual Cues in Macrophages Generated by Granulocyte/Macrophage Colony-Stimulating Factor, Macrophage Colony-Stimulating Factor, and Heat-Killed Mycobacteria

Heat-killed (HK) Mycobacterium obuense (NCTC13365) is currently being evaluated in the clinic as an immunotherapeutic agent for cancer treatment. Yet, the molecular underpinnings underlying immunomodulatory properties of HK M. obuense are still largely undefined. To fill this void, we sought to perform immunophenotyping, chemokine/cytokine release analysis and genome-wide characterization of monocyte-derived macrophages (MDM) in which monocytes were originally isolated from healthy donors and differentiated by HK M. obuense (Mob-MDM) relative to macrophage colony-stimulating factor (M-MDM) and granulocyte/macrophage colony-stimulating factor (GM-MDM). Immunophenotyping and cytokine release analysis revealed downregulated surface expression of CD36, decreased spontaneous release of CCL2 and increased spontaneous secretion of CCL5, CXCL8/IL-8, IL-6, and TNF-α in Mob-MDM relative to M-MDM and GM-MDM. Analysis of cytostatic activity showed that Mob-MDM exhibited similar growth inhibitory effects on immortalized and malignant epithelial cells compared with GM-MDM but at an elevated rate relative to M-MDM. To understand global cues in Mob-MDM, we performed comparative RNA-sequencing (RNA-Seq) analysis of Mob-MDM relative to GM-MDM and M-MDM (n = 4 donors). Clustering analysis underscored expression profiles (n = 256) that were significantly modulated in Mob-MDM versus both M-MDM and GM-MDM including, among others, chemokines/cytokines and their receptors, enzymes and transcriptions factors. Topological functional analysis of these profiles identified pathways and gene sets linked to Mob-MDM phenotype including nitric oxide production, acute phase response signaling and microbe recognition pathways as well as signaling cues mediated by the proinflammatory cytokine, interferon-gamma, and the intracellular pattern recognition receptor, nucleotide-binding oligomerization domain-containing protein 2. Taken together, our study highlights molecular immune phenotypes and global signaling cues in Mob-MDM that may underlie immunomodulatory properties of HK M. obuense. Such properties could be of valuable use in immunotherapy approaches such as adoptive cell therapy against cancer.

Decreased expression of granulocyte-macrophage colony-stimulating factor is associated with adverse clinical outcome in patients with gastric cancer undergoing gastrectomy

Previous studies have revealed the clinical significance of tumor-associated macrophages (TAMs) in gastric cancer, whereas the role of the cytokines that orchestrate TAM polarization in gastric cancer remains elusive. The present study aimed to evaluate the prognostic value of granulocyte-macrophage colony-stimulating factor (GM-CSF) expression in patients with gastric cancer. Intratumoral GM-CSF expression was investigated by immunohistochemical staining in 408 retrospectively enrolled patients. Kaplan-Meier analysis and Cox regression models were used to evaluate the prognostic value of GM-CSF expression. Predictive nomograms were generated to predict the overall survival and disease-free survival rates of the patients. Decreased intratumoral GM-CSF expression was identified, and indicated a poorer clinical outcome for patients with gastric cancer, particularly in advanced stages. Intratumoral GM-CSF expression may provide an additional risk stratification for the prognosis of patients with gastric cancer based on the Tumor-Node-Metastasis (TNM) staging system. Cox multivariate analysis identified GM-CSF expression as an independent prognostic factor for overall survival and disease-free survival time. The generated nomograms performed well in predicting the 3-and 5-year clinical outcome of patients with gastric cancer. In conclusion, GM-CSF is a potential independent prognostic indicator for patients with gastric cancer, which may be integrated with TNM staging systems to improve the predictive accuracy for clinical outcome, particularly in advanced tumors.

Aptamer micelles targeting fractalkine-expressing cancer cells in vitro and in vivo

In this work we hypothesized that the chemokine fractalkine can serve as a cancer molecular target. We engineered aptamer micelles functionalized with an outer poly(ethylene glycol) (PEG) corona, and investigated the extent and efficacy of using them as a targeting tool against fractalkine-expressing colon adenocarcinoma cells. In vitro cell binding results showed that aptamer micelles bound and internalized to fractalkine-expressing cancer cells with the majority of the micelles found free in the cytoplasm. Minimal surface binding was observed by healthy cells. Even though partial PEGylation did not prevent serum adsorption, micelles were highly resistant to endonuclease and exonuclease degradation. In vivo biodistribution studies and confocal studies demonstrated that even though both aptamer and control micelles showed tumor accumulation, only the aptamer micelles internalized into fractalkine-expressing cancer cells, thus demonstrating the potential of the approach and showing that fractalkine may serve as a specific target for nanoparticle delivery to cancer cells.

Role of interleukin (IL)-17 and T-helper (Th)17 cells in cancer

Interleukin-17 (IL-17), a pleiotropic proinflammatory cytokine, is reported to be significantly generated by a distinct subset of CD4⁺ T-cells, upgrading cancer-elicited inflammation and preventing cancer cells from immune surveillance. T-helper (Th)17 cells produced from naive CD4⁺ T cells have recently been renowned and generally accepted, gaining eminence in cancer studies and playing the effective role in context of cancer. Th17 cells are the main source of IL-17-secreting cells, It was found that other cell types produced this cytokine as well, including Group 3 innate lymphoid cells (ILC3), δγT cells, invariant natural killer T (iNKT) cells, lymphoid-tissue inducer (LTi)-like cells and Natural killer (NK) cells. Th17-associated cytokines give impetus to tumor progression, or inducing angiogenesis and metastasis. This review demonstrates an understanding on how the pro- or antitumor function of Th17 cells and IL-17 may change cancer progression, leading to the appearance of complex and pivotal biologic activities in tumor.

An epithelial-to-mesenchymal transition-inducing potential of granulocyte macrophage colony-stimulating factor in colon cancer

Growing evidence shows that granulocyte macrophage colony-stimulating factor (GM-CSF) has progression-promoting potentials in certain solid tumors, which is largely attributed to the immunomodulatory function of this cytokine in tumor niches. However, little is known about the effect of GM-CSF on cancer cells. Herein, we show that chronic exposure of colon cancer cells to GM-CSF, which harbor its receptor, leads to occurrence of epithelial to mesenchymal transition (EMT), in time and dose-dependent manners. These GM-CSF-educated cancer cells exhibit enhanced ability of motility in vitro and in vivo. Furthermore, GM-CSF stimulation renders colon cancer cells more resistant to cytotoxic agents. Mechanistic investigation reveals that MAPK/ERK signaling and EMT-inducing transcription factor ZEB1 are critical to mediate these effects of GM-CSF. In specimen of CRC patients, high-level expression of GM-CSF positively correlates with local metastases in lymph nodes. Moreover, the co-expression of GM-CSF and its receptors as well as phosphorylated ERK1/2 are observed. Thus, our study for the first time identifies a progression-promoting function of GM-CSF in colon cancer by inducing EMT.

The Interplay Between Neutrophils and CD8+ T Cells Improves Survival in Human Colorectal Cancer

Purpose: Tumor infiltration by different T lymphocyte subsets is known to be associated with favorable prognosis in colorectal cancer. Still debated is the role of innate immune system. We investigated clinical relevance, phenotypes, and functional features of colorectal cancer-infiltrating CD66b⁺ neutrophils and their crosstalk with CD8⁺ T cells.Experimental Design: CD66b⁺ and CD8⁺ cell infiltration was analyzed by IHC on a tissue microarray including >650 evaluable colorectal cancer samples. Phenotypic profiles of tissue-infiltrating and peripheral blood CD66b⁺ cells were evaluated by flow cytometry. CD66b⁺/CD8⁺ cells crosstalk was investigated by in vitro experiments.Results: CD66b⁺ cell infiltration in colorectal cancer is significantly associated with increased survival. Interestingly, neutrophils frequently colocalize with CD8⁺ T cells in colorectal cancer. Functional studies indicate that although neutrophils are devoid of direct antitumor potential, coculture with peripheral blood or tumor-associated neutrophils (TAN) enhances CD8⁺ T-cell activation, proliferation, and cytokine release induced by suboptimal concentrations of anti-CD3 mAb. Moreover, under optimal activation conditions, CD8⁺ cell stimulation in the presence of CD66b⁺ cells results in increasing numbers of cells expressing CD45RO/CD62L "central memory" phenotype. Importantly, combined tumor infiltration by CD66b⁺ and CD8⁺ T lymphocytes is associated with significantly better prognosis, as compared with CD8⁺ T-cell infiltration alone.Conclusions: Neutrophils enhance the responsiveness of CD8⁺ T cells to T-cell receptor triggering. Accordingly, infiltration by neutrophils enhances the prognostic significance of colorectal cancer infiltration by CD8⁺ T cells, suggesting that they might effectively promote antitumor immunity. Clin Cancer Res; 23(14); 3847-58. ©2017 AACR.

OX40 expression enhances the prognostic significance of CD8 positive lymphocyte infiltration in colorectal cancer

Background

OX40 is a TNF receptor family member expressed by activated T cells. Its triggering by OX40 ligand promotes lymphocyte survival and memory generation. Anti-OX40 agonistic monoclonal antibodies (mAb) are currently being tested in cancer immunotherapy. We explored the prognostic significance of tumor infiltration by OX40+ cells in a large colorectal cancer (CRC) collective.

Methods

OX40 gene expression was analyzed in 50 freshly excised CRC and corresponding healthy mucosa by qRT-PCR. A tissue microarray including 657 clinically annotated CRC specimens was stained with anti-OX40, -CD8 and -FOXP3 mAbs by standard immunohistochemistry. The CRC cohort was randomly split into training and validation sets. Correlations between CRC infiltration by OX40+ cells alone, or in combination with CD8+ or FOXP3+ cells, and clinical-pathological data and overall survival were comparatively evaluated.

Results

OX40 gene expression in CRC significantly correlated with FOXP3 and CD8 gene expression. High CRC infiltration by OX40+ cells was significantly associated with favorable prognosis in training and validation sets in univariate, but not multivariate, Cox regression analysis. CRC with OX40^high/CD8^high infiltration were characterized by significantly prolonged overall survival, as compared to tumors with OX40^low/CD8^high, OX40^high/CD8^low or OX40^low/CD8^low infiltration in both uni- and multivariate analysis. In contrast, prognostic significance of OX40+ and FOXP3+ cell infiltration was not enhanced by a combined evaluation. Irrespective of TNM stage, CRC with OX40^high/CD8^high density infiltrates showed an overall survival similar to that of all stage I CRC included in the study.

Conclusions

OX40^high/CD8^high density tumor infiltration represents an independent, favorable, prognostic marker in CRC with an overall survival similar to stage I cancers.

Recombinant Poxvirus and the Tumor Microenvironment: Oncolysis, Immune Regulation and Immunization

Oncolytic viruses (OVs) are being extensively studied for their potential roles in the development of cancer therapy regimens. In addition to their direct lytic effects, OVs can initiate and drive systemic antitumor immunity indirectly via release of tumor antigen, as well as by encoding and delivering immunostimulatory molecules. This combination makes them an effective platform for the development of immunotherapeutic strategies beyond their primary lytic function. Engineering the viruses to also express tumor-associated antigens (TAAs) allows them to simultaneously serve as therapeutic vaccines, targeting and amplifying an immune response to TAAs. Our group and others have shown that vaccinating intratumorally with a poxvirus that encodes TAAs, in addition to immune stimulatory molecules, can modulate the tumor microenvironment, overcome immune inhibitory pathways, and drive both local and systemic tumor specific immune responses.

Co-Culture of Tumor Spheroids and Fibroblasts in a Collagen Matrix-Incorporated Microfluidic Chip Mimics Reciprocal Activation in Solid Tumor Microenvironment

Multicellular 3D culture and interaction with stromal components are considered essential elements in establishing a ‘more clinically relevant’ tumor model. Matrix-embedded 3D cultures using a microfluidic chip platform can recapitulate the microscale interaction within tumor microenvironments. As a major component of tumor microenvironment, cancer-associated fibroblasts (CAFs) play a role in cancer progression and drug resistance. Here, we present a microfluidic chip-based tumor tissue culture model that integrates 3D tumor spheroids (TSs) with CAF in proximity within a hydrogel scaffold. HT-29 human colorectal carcinoma cells grew into 3D TSs and the growth was stimulated when co-cultured with fibroblasts as shown by 1.5-folds increase of % changes in diameter over 5 days. TS cultured for 6 days showed a reduced expression of Ki-67 along with increased expression of fibronectin when co-cultured with fibroblasts compared to mono-cultured TSs. Fibroblasts were activated under co-culture conditions, as demonstrated by increases in α-SMA expression and migratory activity. When exposed to paclitaxel, a survival advantage was observed in TSs co-cultured with activated fibroblasts. Overall, we demonstrated the reciprocal interaction between TSs and fibroblasts in our 7-channel microfluidic chip. The co-culture of 3D TS-CAF in a collagen matrix-incorporated microfluidic chip may be useful to study the tumor microenvironment and for evaluation of drug screening and evaluation.

Stimulatory versus suppressive effects of GM-CSF on tumor progression in multiple cancer types

Granulocyte-macrophage colony-stimulating factor (GM-CSF, also called CSF-2) is best known for its critical role in immune modulation and hematopoiesis. A large body of experimental evidence indicates that GM-CSF, which is frequently upregulated in multiple types of human cancers, effectively marks cancer cells with a ‘danger flag' for the immune system. In this context, most studies have focused on its function as an immunomodulator, namely its ability to stimulate dendritic cell (DC) maturation and monocyte/macrophage activity. However, recent studies have suggested that GM-CSF also promotes immune-independent tumor progression by supporting tumor microenvironments and stimulating tumor growth and metastasis. Although some studies have suggested that GM-CSF has inhibitory effects on tumor growth and metastasis, an even greater number of studies show that GM-CSF exerts stimulatory effects on tumor progression. In this review, we summarize a number of findings to provide the currently available information regarding the anticancer immune response of GM-CSG. We then discuss the potential roles of GM-CSF in the progression of multiple types of cancer to provide insights into some of the complexities of its clinical applications.

Cytokine-Induced Modulation of Colorectal Cancer

The emergence of novel immunomodulatory cancer therapies over the last decade, above all immune checkpoint blockade, has significantly advanced tumor treatment. For colorectal cancer (CRC), a novel scoring system based on the immune cell infiltration in tumors has greatly improved disease prognostic evaluation and guidance to more specific therapy. These findings underline the relevance of tumor immunology in the future handling and therapeutic approach of malignant disease. Inflammation can either promote or suppress CRC pathogenesis and inflammatory mediators, mainly cytokines, critically determine the pro- or anti-tumorigenic signals within the tumor environment. Here, we review the current knowledge on the cytokines known to be critically involved in CRC development and illustrate their mechanisms of action. We also highlight similarities and differences between CRC patients and murine models of CRC and point out cytokines with an ambivalent role for intestinal cancer. We also identify some of the future challenges in the field that should be addressed for the development of more effective immunomodulatory therapies.

Sparstolonin B attenuates early liver inflammation in experimental NASH by modulating TLR4 trafficking in lipid rafts via NADPH oxidase activation

Although significant research data exist on the pathophysiology of nonalcoholic steatohepatitis (NASH), finding an efficient treatment regimen for it remains elusive. The present study used sparstolonin B (SsnB), a novel TLR4 antagonist derived from the Chinese herb Sparganium stoloniferum, as a possible drug to mitigate early inflammation in NASH. This study used an early steatohepatitic injury model in high-fat-fed mice with CYP2E1-mediated oxidative stress as a second hit. SsnB was administered for 1 wk along with bromodichloromethane (BDCM), an inducer of CYP2E1-mediated oxidative stress. Results showed that SsnB administration attenuated inflammatory morphology and decreased elevation of the liver enzyme alanine aminotransferase (ALT). Mice administered SsnB also showed decreased mRNA expression of proinflammatory cytokines TNF-α, IFN-γ, IL-1β, and IL-23, while protein levels of both TNF-α and IL-1β were significantly decreased. SsnB significantly decreased Kupffer cell activation as evidenced by reduction in CD68 and monocyte chemoattractant protein-1 (MCP1) mRNA and protein levels with concomitant inhibition of macrophage infiltration in the injured liver. Mechanistically, SsnB decreased TLR4 trafficking to the lipid rafts, a phenomenon described by the colocalization of TLR4 and lipid raft marker flotillin in tissues and immortalized Kupffer cells. Since we have shown previously that NADPH oxidase drives TLR4 trafficking in NASH, we studied the role of SsnB in modulating this pathway. SsnB prevented NADPH oxidase activation in vivo and in vitro as indicated by decreased peroxynitrite formation. In summary, the present study reports a novel use of the TLR4 antagonist SsnB in mitigating inflammation in NASH and in parallel shows a unique molecular mechanism of decreasing nitrative stress.

Ex vivo generation of myeloid-derived suppressor cells that model the tumor immunosuppressive environment in colorectal cancer

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of cells that accumulate in tumor-bearing subjects and which strongly inhibit anti-cancer immune responses. To study the biology of MDSC in colorectal cancer (CRC), we cultured bone marrow cells in conditioned medium from CT26 cells, which are genetically modified to secrete high levels of granulocyte-macrophage colony-stimulating factor. This resulted in the generation of high numbers of CD11b(+) Ly6G(+) granulocytic and CD11b(+) Ly6C(+) monocytic MDSC, which closely resemble those found within the tumor but not the spleen of CT26 tumor-bearing mice. Such MDSC potently inhibited T-cell responses in vitro, a process that could be reversed upon blocking of arginase-1 or inducible nitric oxide synthase (iNOS). We confirmed that inhibition of arginase-1 or iNOS in vivo resulted in the stimulation of cytotoxic T-cell responses. A delay in tumor growth was observed upon functional repression of both enzymes. These data confirm the role of MDSC as inhibitors of T-cell-mediated immune responses in CRC. Moreover, MDSC differentiated in vitro from bone marrow cells using conditioned medium of GM-CSF-secreting CT26 cells, represent a valuable platform to study/identify drugs that counteract MDSC activities.

Absence of myeloperoxidase and CD8 positive cells in colorectal cancer infiltrates identifies patients with severe prognosis

Colorectal cancer (CRC) infiltration by cells expressing myeloperoxidase (MPO) or CD8 positive T lymphocytes has been shown to be independently associated with favorable prognosis. We explored the relationship occurring between CD8+ and MPO+ cell CRC infiltration, its impact on clinical-pathological features and its prognostic significance in a tissue microarray (TMA) including 1,162 CRC. We observed that CRC showing high MPO+ cell infiltration are characterized by a prognosis as favorable as that of cancers with high CD8+ T cell infiltration. However, MPO+ and CD8+ CRC infiltrating cells did not synergize in determining a more favorable outcome, as compared with cancers showing MPOhigh/CD8low or MPOlow/CD8high infiltrates. Most importantly, we identified a subgroup of CRC with MPOlow/CD8low tumor infiltration characterized by a particularly severe prognosis. Intriguingly, although MPO+ and CD8+ cells did not co-localize in CRC infiltrates, an increased expression of TIA-1 and granzyme-B was detectable in T cells infiltrating CRC with high MPO+ cell density.

Emerging cytokine networks in colorectal cancer

Cytokine networks are crucial aspects of tumour immunology, particularly for colorectal cancer (CRC), in which inflammation and antitumour immunity are key determinants of disease progression. In this Review, we highlight new insights into the functions of well-known cytokines in CRC, describe recently discovered roles for a growing number of novel players, and emphasize the complexity and therapeutic implications of the cytokine milieu. We also discuss how cancer mutations and epigenetic adaptations influence the oncogenic potential of cytokines, a relatively unexplored area that could yield crucial insights into tumour immunology and facilitate the effective application of cytokine-modulatory therapies for CRC.

The delicate balance of macrophages in colorectal cancer; their role in tumour development and therapeutic potential

Most tumours are heavily infiltrated by immune cells. This has been correlated with either a good or a bad patient prognosis, depending on the (sub) type of immune cells. Macrophages represent one of the most prominent leukocyte populations in the majority of tumours. Functions of macrophages range from cytotoxicity, to stimulation of tumour growth by secretion of cytokines, growth and angiogenic factors, or suppressing immune responses. In most tumours macrophages are described as cells with immune suppressing, and wound healing properties, which aids tumour development. Yet, increasing evidence shows that macrophages are potent inhibitors of tumour growth in colorectal cancer. Macrophages in this respect show high plasticity. The presence of high macrophage numbers in the tumour may therefore become advantageous, if cells can be reprogrammed from tumour promoting macrophages into potent effector cells. Enhancing cytotoxic properties of macrophages by microbial products, pro-inflammatory cytokines or monoclonal antibody therapy are promising possibilities, and are currently tested in clinical trials.