Cancer anorexia-cachexia syndrome is characterized by more than one inflammatory pathway.

BACKGROUND: The interdependence of cytokines and appetite-modifying hormones implicated in cancer anorexia-cachexia syndrome (CACS) remains unclear. This study aimed to regroup these cytokines and hormones into distinct inflammatory (or non-inflammatory) pathways and determine whether these pathways can classify patients with CACS phenotypes. METHODS: Clinical characteristics of 133 patients [61.7% male; mean age = 63.4 (SD: 13.1) years] with advanced cancer prior to oncology treatments were documented, including weight loss history. Patients completed the Functional Assessment of Anorexia-Cachexia Therapy (FAACT) questionnaire and Timed Up and Go test and had their sex-standardized skeletal muscle index (z-SMI) and fat mass index (z-FMI) derived using computed tomography scans. Their plasma levels of cytokines and appetite-modifying hormones were also determined. Date of death was recorded. Exploratory factor analysis (EFA) was used to regroup 15 cytokines and hormone into distinct inflammatory pathways (factors). For each patient, regression factor scores (RFS), which tell how strongly the patient associates with each factor, were derived. Two-step cluster analysis on the RFS was used to classify patients into groups. CACS phenotypes were correlated with RFS and compared between groups. Groups' survival was estimated using Kaplan-Meier analysis. RESULTS: Patients had low z-SMI (mean = -3.78 cm2/m2; SD: 8.88) and z-FMI (mean = 0.08 kg2/m2; SD: 56.25), and 62 (46.6%) had cachexia. EFA identified three factors: (F-1) IFN-γ, IL-1ß, Il-4, IL-6, IL-10, IL-12, TGFß1 (positive contribution), and IL-18 (negative); (F-2) IL-8, IL-18, MCP-1, TGFß1, TNF-α (positive), and ghrelin (negative); and (F-3) TRAIL and leptin (positive), and TGFß1 and adiponectin (negative). RFS-1 was associated with cachexia (P = 0.002); RFS-2, with higher CRP (P < 0.0001) and decreased physical function (P = 0.01); and RFS-3 with better appetite (P = 0.04), lower CRP (P = 0.002), higher z-SMI (P = 0.04) and z-FMI (P < 0.0001), and less cachexia characteristics (all P < 0.001). Four patient groups were identified with specific RFS clusters aligning with the CACS continuum from no cachexia to pre-cachexia, cachexia, and terminal cachexia. Compared to the other two groups, groups 1 and 2 had higher plasma levels of IL-18 and TRAIL. Group 1 also had lower inflammatory cytokines, adiponectin, and CRP compared to the other three groups. Group 3 had inflammatory cytokine levels similar to group 2, except for TNF-α and leptin which were lower. Group 4 had very high inflammatory cytokines, adiponectin, and CRP compared to the other 3 groups (all P < 0.0001). Groups 3 and 4 had worse cachexia characteristics (P < 0.05) and shorter survival (log rank: P = 0.0009) than the other two groups. CONCLUSIONS: This exploratory study identified three distinct pathways of inflammation, or lack thereof, characterizing different CACS phenotypes.

Mining the Complex Family of Protein Tyrosine Phosphatases for Checkpoint Regulators in Immunity.

The family of protein tyrosine phosphatases (PTPs) includes 107 genes in humans that are diverse in their structures and expression profiles. The majority are present in immune cells and play various roles in either inhibiting or promoting the duration and amplitude of signaling cascades. Several PTPs, including TC-PTP (PTPN2) and SHP-1 (PTPN6), have been recognized as being crucial for maintaining proper immune response and self-tolerance, and have gained recognition as true immune system checkpoint modulators. This chapter details the most recent literature on PTPs and immunity by examining their known functions in regulating signaling from either established checkpoint inhibitors or by their intrinsic properties, as modulators of the immune response. Notably, we review PTP regulatory properties in macrophages, antigen-presenting dendritic cells, and T cells. Overall, we present the PTP gene family as a remarkable source of novel checkpoint inhibitors wherein lies a great number of new targets for immunotherapies.

Downregulation of PTP1B and TC-PTP phosphatases potentiate dendritic cell-based immunotherapy through IL-12/IFNγ signaling.

PTP1B and TC-PTP are highly related protein-tyrosine phosphatases (PTPs) that regulate the JAK/STAT signaling cascade essential for cytokine-receptor activation in immune cells. Here, we describe a novel immunotherapy approach whereby monocyte-derived dendritic cell (moDC) function is enhanced by modulating the enzymatic activities of PTP1B and TC-PTP. To downregulate or delete the activity/expression of these PTPs, we generated mice with PTP-specific deletions in the dendritic cell compartment or used PTP1B and TC-PTP specific inhibitor. While total ablation of PTP1B or TC-PTP expression leads to tolerogenic DCs via STAT3 hyperactivation, downregulation of either phosphatase remarkably shifts the balance toward an immunogenic DC phenotype due to hyperactivation of STAT4, STAT1 and Src kinase. The resulting increase in IL-12 and IFNγ production subsequently amplifies the IL-12/STAT4/IFNγ/STAT1/IL-12 positive autocrine loop and enhances the therapeutic potential of mature moDCs in tumor-bearing mice. Furthermore, pharmacological inhibition of both PTPs improves the maturation of defective moDCs derived from pancreatic cancer (PaC) patients. Our study provides a new advance in the use of DC-based cancer immunotherapy that is complementary to current cancer therapeutics.

Identification of neutrophil-derived proteases and angiotensin II as biomarkers of cancer cachexia.

BACKGROUND: Cachexia is a metabolic disorder characterised by muscle wasting, diminished response to anti-cancer treatments and poor quality of life. Our objective was to identify blood-based biomarkers of cachexia in advanced cancer patients. Hence, we characterised the plasma cytokine and blood cell mRNA profiles of patients grouped in three cohorts: patients with cachexia, pre-cachexia (no cachexia but high CRP levels: ⩾ 5 mg l⁻¹) and no cachexia (no cachexia and CRP: < 5 mg l⁻¹). METHODS: A total of 122 newly diagnosed cancer patients with seven cancer types were studied prior to their initial therapy. Plasma levels of 22 cytokines were quantified using the bio-plex technology. mRNAs isolated from whole blood and expression profiles were determined by the chip array technology and Ingenuity Pathway Analysis (IPA) software. RESULTS: In comparison with non-cachectic individuals, both pre-cachectic and cachectic patients showed an increase (⩾ 1.5-folds) in mRNA expression of neutrophil-derived proteases (NDPs) and significantly elevated angiotensin II (Ang II) (P = 0.005 and P = 0.02, respectively), TGFß1 (P = 0.042 and P < 0.0001, respectively) and CRP (both P < 0.0001) in the plasma. Moreover, cachectic patients displayed a significant increase in IL-6 (P = 0.005), IL-8 (P = 0.001) and absolute neutrophil counts (P = 0.007). CONCLUSIONS: Ang II, TGFß1, CRP and NDP are blood biomarkers for cancer cachexia. These findings contribute to early diagnosis and prevention of cachexia.

FIST, a sword and shield fusokine for cancer immunotherapy.

To antagonize tumor-derived TGFß contemporaneously to anticancer immunotherapy, we genetically engineered a fusion protein coupling IL-2 and the ectodomain of TGFß receptor II (Fusion of Interleukin-2 and Soluble TGFß receptor - a.k.a. FIST). FIST possesses intriguing gain-of-function properties and induces potent activation of IL2-receptor expressing cells and inhibits tumor-derived angiogenesis. Thus FIST constitutes a first-in-class biological that couples anti-angiogenesis to an immune antitumor response.

B effector cells activated by a chimeric protein consisting of IL-2 and the ectodomain of TGF-ß receptor II induce potent antitumor immunity.

We have previously shown that interleukin (IL)-2 receptor-expressing lymphoid cells stimulated with a chimeric protein linking IL-2 to the ectodomain of TGF-ß receptor II (also known as FIST) become resistant to TGF-ß-mediated suppression and produce significant amounts of proinflammatory cytokines. In this study, we have characterized the antigen presentation properties of FIST-stimulated B cells (hereafter inducible B effector cells, iBEC). FIST converts naïve splenic B cells to B effector cells characterized by potent antigen presentation properties and production of TNFα and IFNγ. iBECs display hyperphosphorylation of STAT3 and STAT5 downstream of the IL-2 receptor and upregulation of T-bet expression. iBECs maintain B-cell identity based on the expression of PAX5 and CD19 and overexpress Smad7, which confers resistance to TGF-ß-mediated suppression of B-cell activation. iBEC antitumor immunity was determined by a mouse model of lymphoma-expressing ovalbumin (E.G7-OVA) as a specific tumor antigen. OVA-pulsed iBECs function as antigen-presenting cells (APC) in vitro by inducing the activation of OVA-specific CD4(+) and CD8(+) T cells, respectively, and in vivo by conferring complete protective immunity against E.G7-OVA tumor challenge. In addition, OVA-pulsed iBECs promote tumor regression in immunocompetent C57Bl/6 mice bearing E.G7-OVA tumors. In conclusion, iBECs represent an entirely novel B cell-derived APC for immune therapy of cancer.

Novel TGF-beta antagonist inhibits tumor growth and angiogenesis by inducing IL-2 receptor-driven STAT1 activation.

Carcinoma derived TGF-ß acts as a potent pro-oncogenic factor and suppresses antitumor immunity. To antagonize TGF-ß-mediated effects in tandem with a proinflammatory immune stimulus, we generated a chimeric protein borne of the fusion of IL-2 and the soluble extracellular domain of TGF-ßR II (FIST). FIST acts as a decoy receptor trapping active TGF-ß in solution and interacts with IL-2-responsive lymphoid cells, inducing a distinctive hyperactivation of STAT1 downstream of IL-2R, which in turn promotes SMAD7 overexpression. Consequently, FIST-stimulated lymphoid cells are resistant to TGF-ß-mediated suppression and produce significant amounts of proinflammatory cytokines. STAT1 hyperactivation further induces significant secretion of angiostatic CXCL10. Moreover, FIST upregulates T-bet expression in NK cells promoting a potent Th1-mediated antitumor response. As a result, FIST stimulation completely inhibits pancreatic cancer (PANC02) and melanoma (B16) tumor growth in immunocompetent C57BL/6 mice. In addition, melanoma cells expressing FIST fail to form tumors in CD8(-/-), CD4(-/-), B cell-deficient (µMT), and beige mice, but not in NOD-SCID and Rag2/γc knockout mice, consistent with the pivotal role of FIST-responsive, cancer-killing NK cells in vivo. In summary, FIST constitutes a novel strategy of treating cancer that targets both the host's angiogenic and innate immune response to malignant cells.

The human ortholog of granulocyte macrophage colony-stimulating factor and interleukin-2 fusion protein induces potent ex vivo natural killer cell activation and maturation.

Natural killer (NK) cells are appealing cellular pharmaceuticals for cancer therapy because of their innate ability to recognize and kill tumor cells. Therefore, the development of methods that can enhance the potency in their anticancer effect would be desirable. We have previously shown that a murine granulocyte macrophage colony-stimulating factor (GM-CSF)/interleukin 2 (IL-2) fusion protein displays novel antitumor properties in vivo compared with both cytokines in combination due to recruitment of NK cells. In the present work, we have found that human ortholog of the GM-CSF/IL-2 fusion protein (a.k.a. hGIFT2) induces robust NK cell activation ex vivo with significant secretion of RANTES and a 37-fold increase in IFNgamma production when compared with either IL-2 or GM-CSF single cytokine treatment or their combination. Moreover, hGIFT2 upregulates the expression of NK cell activating receptors NKp44, NKp46, and DNAM-1 (CD226), as well as CD69, CD107a, and IL-2Rbeta expression. In addition, hGIFT2 promotes NK cell maturation, based on the downregulation of CD117 expression and upregulation of CD11b. This phenotype correlates with significantly greater cytotoxicity against tumor cells. At the molecular level, hGIFT2 leads to a potent activation of Janus-activated kinases (JAK) downstream of both IL-2 and GM-CSF receptors (JAK1 and JAK2, respectively) and consequently leads to a hyperphosphorylation of signal transducers and activators of transcription (STAT)1, STAT3, and STAT5. In conclusion, hGIFT2 fusokine possesses unique biochemical properties distinct from IL-2 and GM-CSF, constitutes a novel and potent tool for ex vivo NK cell activation and maturation, and may be of use for cancer cell immunotherapy.

TGF beta secreted by B16 melanoma antagonizes cancer gene immunotherapy bystander effect.

Tumor-targeted delivery of immune stimulatory genes, such as pro-inflammatory cytokines and suicide genes, has shown to cure mouse models of cancer. Total tumor eradication was also found to occur despite subtotal tumor engineering; a phenomenon coined the "bystander effect". The bystander effect in immune competent animals arises mostly from recruitment of a cancer lytic cell-mediated immune response to local and distant tumor cells which escaped gene modification. We have previously described a Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) and Interleukin 2 (IL2) fusokine (aka GIFT2) which serves as a potent anticancer cytokine and it here served as a means to understand the mechanistic underpinnings to the immune bystander effect in an immune competent model of B16 melanoma. As expected, we observed that GIFT2 secreted by genetically engineered B16 tumor cells induces a bystander effect on non modified B16 cells, when admixed in a 1:1 ratio. However, despite keeping the 1:1 ratio constant, the immune bystander effect was completely lost as the total B16 cell number was increased from 10(4) to 10(6) which correlated with a sharp reduction in the number of tumor-infiltrating NK cells. We found that B16 secrete biologically active TGFbeta which in turn inhibited GIFT2 dependent immune cell proliferation in vitro and downregulated IL-2R beta expression and IFN gamma secretion by NK cells. In vivo blockade of B16 originating TGFbeta significantly improved the immune bystander effect arising from GIFT2. We propose that cancer gene immunotherapy of pre-established tumors will be enhanced by blockade of tumor-derived TGFbeta.

A CRM1-dependent nuclear export pathway is involved in the regulation of IRF-5 subcellular localization.

Interferon regulatory factors (IRFs) are involved in gene regulation in many biological processes including the antiviral, growth regulatory, and immune modulatory functions of the interferon system. Several studies have demonstrated that IRF-3, IRF-5, and IRF-7 specifically contribute to the innate antiviral response to virus infection. It has been reported that virus-specific phosphorylation leads to IRF-5 nuclear localization and up-regulation of interferon, cytokine, and chemokine gene expression. Two nuclear localization signals have been identified in IRF-5, both of which are sufficient for nuclear translocation and retention in virus-infected cells. In the present study, we demonstrate that a CRM1-dependent nuclear export pathway is involved in the regulation of IRF-5 subcellular localization. IRF-5 possesses a functional nuclear export signal (NES) that controls dynamic shuttling between the cytoplasm and the nucleus. The NES element is dominant in unstimulated cells and results in the predominant cytoplasmic localization of IRF-5. Mutation of two leucine residues in the NES motif to alanine, or three adjacent Ser/Thr residues to the phosphomimetic Asp, results in constitutively nuclear IRF-5 and suggests that phosphorylation of adjacent Ser/Thr residues may contribute to IRF-5 nuclear accumulation in virus-induced cells. IKK-related kinases TBK1 and IKKepsilon have been shown to phosphorylate and activate IRF-3 and IRF-7, leading to the production of type 1 interferons and the development of a cellular antiviral state. We examined the phosphorylation and activation of IRF-5 by TBK1 and IKKepsilon kinases. Although IRF-5 is phosphorylated by IKKepsilon and TBK1 in co-transfected cells, the phosphorylation of IRF-5 did not lead to IRF-5 nuclear localization or activation.