Complement inhibition in cancer therapy

An herbal formula Shenlian decoction upregulates M1/M2 macrophage proportion in hepatocellular carcinoma by suppressing complement cascade

The immunosuppressive microenvironment is a vital factor for the hepatocellular carcinoma (HCC) progression. However, effective treatment is lacking at current. Shenlian decoction (SLD) is a registered herbal therapy for the HCC treatment, but the underlying mechanism of SLD remains largely elusive. Here, we aimed to explore the anti-tumor effect of SLD in the treatment of HCC. SLD was intragastrically given after the tumor initiation in β-catenin/C-Met or DEN and CCl4 induced HCC mouse model. The tumor growth levels were evaluated by liver weight and histological staining. The tumor-infiltrating immune cells were detected by immunological staining and flow cytometry. The mechanism of the SLD was detected by non-targeted proteomics and verified by a cell co-culture system. The result showed that SLD significantly attenuated HCC progression. SLD promoted macrophage infiltration and increased the M1/M2 macrophage ratio within the tumor tissues. Non-targeted proteomics showed the inhibition of complement C5/C5a signaling is the key mechanism of SLD. Immunological staining showed SLD inhibited C5/C5a expression and C5aR1+ macrophage infiltration. The suggested mechanism was demonstrated by application of C5aR1 inhibitor, PMX-53 in mouse HCC model. Hepatoma cell-macrophage co-culture showed SLD targeted hepatoma cells and inhibited the supernatant-induced macrophage M2 polarization. SLD inhibited AMPK/p38 signaling which is an upstream mechanism of C5 transcription. In conclusion, we found SLD relieved immune-suppressive environment by inhibiting C5 expression. SLD could suppress the C5 secretion in hepatoma cells via inhibition of AMPK/p38 signaling. We suggested that SLD is a potential herbal therapy for the treatment of HCC by alleviating immune-suppressive status.

Identification and immunoassay of prognostic genes associated with the complement system in acute myeloid leukemia

Studies have associated the development of pulmonary leukemia with the activation of the complement system. However, the roles and mechanisms of complement system-related genes (CSRGs) in acute myeloid leukemia (AML) have not been investigated extensively. This study used The Cancer Genome Atlas (TCGA)-AML and GSE37642 datasets. Differentially expressed CSRGs (CSRDEGs) were identified by overlapping genes differentially expressed between the high and low CSRG score groups and key module genes identified in a weighted gene co-expression network analysis. Univariate and multivariate Cox analyses identified CSRG-related biomarkers, which were used to build a prognostic model. After gene set enrichment analysis (GSEA), immune-related and drug-sensitivity analyses were performed in the high- and low-risk groups. Four prognosis-related biomarkers were identified and used to develop a prognostic model: MEOX2, IGFBP5, CH25H, and RAB3B. The model's performance was verified in a test cohort (a subset of samples from the TCGA-AML dataset) and a validation cohort (GSE37642). The GSEA revealed that the high-risk group was mainly enriched for Golgi organization and cytokine-cytokine receptor interactions, and the low-risk group was mainly enriched in the hedgehog signaling pathway and spliceosome. Lastly, two immune cells were found to show differential infiltration between risk groups, which correlated with the risk scores. M1 macrophage infiltration was significantly positively correlated with RAB3B expression. Sensitivity to 36 drugs differed significantly between risk groups. This study screened four CSRG-related biomarkers (MEOX2, IGFBP5, CH25H, and RAB3B) to provide a basis for predicting AML prognosis.

Improving radiotherapy in immunosuppressive microenvironments by targeting complement receptor C5aR1

An immunosuppressive microenvironment causes poor tumor T cell infiltration and is associated with reduced patient overall survival in colorectal cancer. How to improve treatment responses in these tumors is still a challenge. Using an integrated screening approach to identify cancer-specific vulnerabilities, we identified complement receptor C5aR1 as a druggable target, which when inhibited improved radiotherapy, even in tumors displaying immunosuppressive features and poor CD8+ T cell infiltration. While C5aR1 is well-known for its role in the immune compartment, we found that C5aR1 is also robustly expressed on malignant epithelial cells, highlighting potential tumor cell-specific functions. C5aR1 targeting resulted in increased NF-κB-dependent apoptosis specifically in tumors and not normal tissues, indicating that, in malignant cells, C5aR1 primarily regulated cell fate. Collectively, these data revealed that increased complement gene expression is part of the stress response mounted by irradiated tumors and that targeting C5aR1 could improve radiotherapy, even in tumors displaying immunosuppressive features.

Comprehensive analysis of subtypes and risk model based on complement system associated genes in ccRCC

BACKGROUND

Immune therapy is widely used in treating clear cell renal cell carcinoma (ccRCC), yet identifying patient subgroups that are expected to response remains challenging. As complement system can mediate immune effects, including the progression of tumors, a correlation between complement system and immune therapy may exist.

METHODS

Based on 11 complement system associated genes (CSAGs) identified from The Cancer Genome Atlas (TCGA), we performed unsupervised clustering and classified the tumors into two different complement system (CS) patterns. The clinical significance, tumor microenvironment (TME), functional enrichment, and immune infiltration were further analyzed. A novel scoring system named CSscore was developed based on the expression levels of the 11 CSAGs.

RESULTS

Two distinct CS patterns were identified, classified as Cluster1 and Cluster2, and Cluster1 showed poor clinical outcome. Further analysis of functional enrichment, immune cell infiltration, and genetic variation revealed that Cluster1 had high infiltration of TME immune cells, but also exhibited high immune escape. The novel prognostic model, CSscore could act as an independent prognostic factor and effectively predict patients' prognosis and distinguish the therapeutic efficacy of different immune treatment strategies. The pan-cancer analysis of the CSscore indicates its potential to be further generalized to other types of cancer.

CONCLUSIONS

Two distinct CS patterns were identified and were further analyzed in terms of infiltration of TME immune cells and immune escape, providing potential explanations for the impact on prognosis of ccRCC. Our CSscore prognostic model may offer a novel perspective in the management of ccRCC patients, and potentially other types of cancer as well.

Prognostic Model and Tumor Immune Microenvironment Analysis of Complement-Related Genes in Gastric Cancer

Introduction

The complement system is integral to the innate and adaptive immune response, helping antibodies eliminate pathogens. However, the potential role of complement and its modulators in the tumor microenvironment (TME) of gastric cancer (GC) remains unclear.

Methods

This study assessed the expression, frequency of somatic mutations, and copy number variations of complement family genes in GC derived from The Cancer Genome Atlas (TCGA). Lasso and Cox regression analyses were conducted to develop a prognostic model based on the complement genes family, with the training and validation sets taken from the TCGA-GC cohort (n=371) and the International Gene Expression Omnibus (GEO) cohort (n=433), correspondingly. The nomogram assessment model was used to predict patient outcomes. Additionally, the link between immune checkpoints, immune cells, and the prognostic model was investigated.

Results

In contrast to patients at low risk, those at high risk had a less favorable outcome. The prognostic model-derived risk score was shown to serve as a prognostic marker of GC independently, as per the multivariate Cox analysis. Nomogram assessment showed that the model had high reliability for predicting the survival of patients with GC in the 1, 3, 5 years. Additionally, the risk score was positively linked to the expression of immune checkpoints, notably CTLA4, LAG3, PDCD1, and CD274, according to an analysis of immune processes. The core gene C5aR1 in the prognostic model was found to be upregulated in GC tissues in contrast to adjoining normal tissues, and patients with elevated expressed levels of C5aR1 had lower 10-year overall survival (OS) rates.

Conclusion

Our work reveals that complement genes are associated with the diversity and complexity of TME. The complement prognosis model help improves our understanding of TME infiltration characteristics and makes immunotherapeutic strategies more effective.

Gut Microbiota and Therapy in Metastatic Melanoma: Focus on MAPK Pathway Inhibition

Gut microbiome (GM) and its either pro-tumorigenic or anti-tumorigenic role is intriguing and constitutes an evolving landscape in translational oncology. It has been suggested that these microorganisms may be involved in carcinogenesis, cancer treatment response and resistance, as well as predisposition to adverse effects. In melanoma patients, one of the most immunogenic cancers, immune checkpoint inhibitors (ICI) and MAPK-targeted therapy—BRAF/MEK inhibitors—have revolutionized prognosis, and the study of the microbiome as a modulating factor is thus appealing. Although BRAF/MEK inhibitors constitute one of the main backbones of treatment in melanoma, little is known about their impact on GM and how this might correlate with immune re-induction. On the contrary, ICI and their relationship to GM has become an interesting field of research due to the already-known impact of immunotherapy in modulating the immune system. Immune reprogramming in the tumor microenvironment has been established as one of the main targets of microbiome, since it can induce immunosuppressive phenotypes, promote inflammatory responses or conduct anti-tumor responses. As a result, ongoing clinical trials are evaluating the role of fecal microbiota transplant (FMT), as well as the impact of using dietary supplements, antibiotics and probiotics in the prediction of response to therapy. In this review, we provide an overview of GM’s link to cancer, its relationship with the immune system and how this may impact response to treatments in melanoma patients. We also discuss insights about novel therapeutic approaches including FMT, changes in diet and use of probiotics, prebiotics and symbiotics. Finally, we hypothesize on the possible pathways through which GM may impact anti-tumor efficacy in melanoma patients treated with targeted therapy, an appealing subject of which little is known.

Neutrophils activated by membrane attack complexes increase the permeability of melanoma blood vessels

Cancer cell dissemination is the seed for metastasis and adversely linked to patients’ benefit. Critical for hematogenous dissemination is the entrance of the cancer cell into the circulation, which is regulated by vascular permeability within the primary tumor. Here, we describe pathophysiological communication between endothelial cells, tumor infiltrating neutrophils, and the complement system, with implications for vascular barrier opening and melanoma cell dissemination. Experiments in complement-deficient animals indicate that interference with complement-mediated activation of neutrophils stabilizes blood vessel integrity and abolishes the systemic spread of melanoma cells.

The microenvironment of malignant melanomas defines the properties of tumor blood vessels and regulates infiltration and vascular dissemination of immune and cancer cells, respectively. Previous research in other cancer entities suggested the complement system as an essential part of the tumor microenvironment. Here, we confirm activation of the complement system in samples of melanoma patients and murine melanomas. We identified the tumor endothelium as the starting point of the complement cascade. Generation of complement-derived C5a promoted the recruitment of neutrophils. Upon contact with the vascular endothelium, neutrophils were further activated by complement membrane attack complexes (MACs). MAC-activated neutrophils release neutrophil extracellular traps (NETs). Close to the blood vessel wall, NETs opened the endothelial barrier as indicated by an enhanced vascular leakage. This facilitated the entrance of melanoma cells into the circulation and their systemic spread. Depletion of neutrophils or lack of MAC formation in complement component 6 (C6)–deficient animals protected the vascular endothelium and prevented vascular intravasation of melanoma cells. Our data suggest that inhibition of MAC-mediated neutrophil activation is a potent strategy to abolish hematogenous dissemination in melanoma.

Sialic acids: An Avenue to Target Cancer Progression, Metastasis, and Resistance to Therapy

Background

Sialic acids are alpha-keto acids with nine carbons that are commonly present in the terminal sugars of glycans on glycoproteins and glycolipids on the cell surface. Sialic acids have a role in a variety of physiological and pathological processes by interacting with carbohydrates and proteins, communicating between cells, and acting as cell surface receptors for viruses and bacteria. Several studies have shown the aberrant pattern of sialic acids on cancer cells due to change in their glycosylation status. This pattern may be attributed to various physiological and pathological changes occurring in tumour cells. Hypersialylation in tumours, its involvement in tumour growth, immune evasion and escape from the apoptotic pathway, metastasis formation, and therapeutic resistance have all been fairly well investigated.

Methods

A PubMed search was conducted and published articles in different studies from 2000 to 2020 were included and reviewed. Here, we discuss current outcomes that emphasize the unfavourable effects of hypersialylation on multiple aspects of tumour genesis, immune evasion, metastasis and resistance to therapy.

Conclusion

These recent investigations have found that aberrant sialylation is an essential process for tumour cells to evade immune surveillance and maintain their malignancy. Together, these noteworthy views provide a solid platform for designing and developing therapeutic approaches that target hypersialylation of cancer cells.

High complement protein C1q levels in pulmonary fibrosis and non-small cell lung cancer associated with poor prognosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common type of interstitial pneumonia. Lung cancer, mainly non-small cell lung cancer (NSCLC), is a complication of idiopathic pulmonary fibrosis. IPF is also an independent risk factor of lung cancer. Some studies have shown that the complement system can promote the progression of interstitial pulmonary fibrosis. In addition, C1q has also demonstrated to exert a tumor-promoting effect in many tumors. However, the role of C1q in idiopathic pulmonary fibrosis and lung cancer still remain unclear.

METHODS

We selected common differentially expressed genes in IPF and non-small cell lung cancer using datasets from GEO, and investigated common hub gene. The hub genes were validated in IPF by establishing mouse model of IPF and using another four datasets from the GEO. Multiple databases were analyzed including those of Kaplan-Meier Plotter, Tumor Immune Estimation Resource (TIMER2.0) and the Human Protein Atlas (HPA) for NSCLC.

RESULTS

In this study, 37 common DEGs were identified in IPF and NSCLC including 32 up-regulated genes and 5 down-regulated genes, and C1q was identified as common hub gene. The methylation status of C1q decreased and the expression levels of C1q increased in both lung cancer and idiopathic pulmonary fibrosis. The prognosis of non-small cell lung cancer and IPF patients with high levels of C1q is poor.

CONCLUSIONS

These results show that C1q participates in pulmonary fibrosis and non-small cell lung cancer, and may be a potential diagnostic / prognostic biomarker or a therapeutic target.

Detection of Circulating Serum Protein Biomarkers of Non-Muscle Invasive Bladder Cancer after Protein Corona-Silver Nanoparticles Analysis by SWATH-MS

Because cystoscopy is expensive and invasive, a new method of detecting non-invasive muscular bladder cancer (NMIBC) is needed. This study aims to identify potential serum protein markers for NMIBC to improve diagnosis and to find treatment approaches that avoid disease progression to a life-threatening phenotype (muscle-invasive bladder cancer, MIBC). Here, silver nanoparticles (AgNPs, 9.73 ± 1.70 nm) as a scavenging device together with sequential window acquisition of all theoretical mass spectra (SWATH-MS) were used to quantitatively analyze the blood serum protein alterations in two NMIBC subtypes, T1 and Ta, and they were compared to normal samples (HC). NMIBC’s analysis of serum samples identified three major groups of proteins, the relative content of which is different from the HC content: proteins implicated in the complement and coagulation cascade pathways and apolipoproteins. In conclusion, many biomarker proteins were identified that merit further examination to validate their useful significance and utility within the clinical management of NMIBC patients.

Complement Component C3: A Novel Biomarker Participating in the Pathogenesis of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disorder worldwide. The pathological spectrum of NAFLD ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) that induces progressive liver cirrhosis and eventually hepatocellular carcinoma (HCC). However, the molecular mechanisms driving the transformation of NASH are obscure. There is a compelling need for understanding the pathogenic mechanisms of NASH, and thereby providing new insight into mechanism-based therapy. Currently, several studies reported that complement system, an innate immune system, played an important role in the pathogenesis of NAFLD, which was also proved by our recent study. Complement component 3 (C3), a protein of the innate immune system, plays a hub role in the complement system. Herein, we present a review on the role and molecular mechanism of C3 in NASH as well as its implication in NASH diagnosis and treatment.

The Complement System in Ovarian Cancer: An Underexplored Old Path

Ovarian cancer is one of the most lethal gynecological cancers. Current therapeutic strategies allow temporary control of the disease, but most patients develop resistance to treatment. Moreover, although successful in a range of solid tumors, immunotherapy has yielded only modest results in ovarian cancer. Emerging evidence underscores the relevance of the components of innate and adaptive immunity in ovarian cancer progression and response to treatment. Particularly, over the last decade, the complement system, a pillar of innate immunity, has emerged as a major regulator of the tumor microenvironment in cancer immunity. Tumor-associated complement activation may support chronic inflammation, promote an immunosuppressive microenvironment, induce angiogenesis, and activate cancer-related signaling pathways. Recent insights suggest an important role of complement effectors, such as C1q or anaphylatoxins C3a and C5a, and their receptors C3aR and C5aR1 in ovarian cancer progression. Nevertheless, the implication of these factors in different clinical contexts is still poorly understood. Detailed knowledge of the interplay between ovarian cancer cells and complement is required to develop new immunotherapy combinations and biomarkers. In this context, we discuss the possibility of targeting complement to overcome some of the hurdles encountered in the treatment of ovarian cancer.

Immunomodulatory and cytotoxic activities of euphol

AIMS

This study evaluated the effect of euphol isolated from Euphorbia umbellata (Pax) Bruyns latex on the activation of complement pathways (classical (CP), alternative (AP) and lectin (LP)), neutrophil chemotaxis, cytotoxic activity, cell morphology and death in HRT-18 and 3T3 cells lines.

MAIN METHODS

CP and AP were assessed using hemolytic assays and ELISA for LP; neutrophil chemotaxis was performed using Boyden's chamber; cytotoxicity was evaluated by neutral red methodology and characteristics of cell death were assessed by cell morphology with hematological staining.

KEY FINDINGS

Although euphol increased CP activation (38% at a concentration of 976.1 μM), an inhibitory effect on AP, LP (31% and 32% reduction in the concentration of 976.1 μM) and neutrophil chemotaxis (inhibit 84% of neutrophil migration at a concentration 292.9 μM) was observed. In addiction euphol was able to induce significant cell death in a time-dependent manner, presenting an IC₅₀ of 70.8 μM and 39.2 μM for HRT-18 and 3T3 cell lines respectively and it was also observed apoptotic characteristics as cellular rounding, chromatin condensation and blebs formation for both cell lines.

SIGNIFICANCE

Euphol has a potential use for the treatment of complement-related inflammatory diseases due to its ability to downregulate inflammation. On the other hand, the controlled activation of CP can contribute to complement-dependent cytotoxicity in the context of monoclonal antibody-based cancer treatment.

Recipient C7 rs9292795 genotype and the risk of hepatocellular carcinoma recurrence after orthotopic liver transplantation in a Han Chinese population

BACKGROUND

Complement component(C7) gene has been shown to influence the prognosis in Hepatocellular carcinoma (HCC) patients. The association between C7 and HCC recurrence after orthotopic liver transplantation (OLT), however, is still unknown. The purpose of this study was to evaluate whether the donor and recipient C7 gene polymorphisms are related to HCC recurrence after OLT in the Han Chinese population.

METHODS

A total of 73 consecutive patients with HCC who had undergone OLT, both donors and recipients, were involved in this research. A single nucleotide polymorphism of C7, rs9292795, was genotyped using Sequenom MassARRAY in the cohort. The expression of C7 and the association between C7 gene polymorphisms and HCC recurrence following OLT were analyzed by bioinformatics and statistical analysis, respectively.

RESULTS

As shown in database, the expression of C7 was higher in HCC tissues than that in normal tissues, and represented a worse prognosis. We also found that recipient C7 rs9292795 polymorphism, rather than the donor, was significantly associated with HCC recurrence after OLT. Multivariate logistic regression analysis confirmed that TNM stage (P = 0.001), Milan criteria (P = 0.000) and recipient rs9292795 genotype (TT vs AA/AT, P = 0.008) were independent risk factors for HCC recurrence. Furthermore, the recipient carrying AA/AT showed higher recurrence-free survival (RFS) and overall survival (OS) than that carrying TT (P < 0.05). In Cox proportional hazards model, TNM stage, recipient rs9292795 genotype, and Milan criteria were identified as independent factors for RFS and OS (P < 0.05) as well as pre-OLT serum alpha fetoprotein (AFP) level was associated with OS (P < 0.05).

CONCLUSIONS

Recipient C7 rs9292795 gene polymorphism is related to the recurrence of HCC after OLT, which may be a helpful prognostic marker for HCC patients who receive OLT.

Modulated Electro-Hyperthermia Induces a Prominent Local Stress Response and Growth Inhibition in Mouse Breast Cancer Isografts

Modulated electro-hyperthermia (mEHT) is a selective cancer treatment used in human oncology complementing other therapies. During mEHT, a focused electromagnetic field (EMF) is generated within the tumor inducing cell death by thermal and nonthermal effects. Here we investigated molecular changes elicited by mEHT using multiplex methods in an aggressive, therapy-resistant triple negative breast cancer (TNBC) model. 4T1/4T07 isografts inoculated orthotopically into female BALB/c mice were treated with mEHT three to five times. mEHT induced the upregulation of the stress-related Hsp70 and cleaved caspase-3 proteins, resulting in effective inhibition of tumor growth and proliferation. Several acute stress response proteins, including protease inhibitors, coagulation and heat shock factors, and complement family members, were among the most upregulated treatment-related genes/proteins as revealed by next-generation sequencing (NGS), Nanostring and mass spectrometry (MS). pathway analysis demonstrated that several of these proteins belong to the response to stimulus pathway. Cell culture treatments confirmed that the source of these proteins was the tumor cells. The heat-shock factor inhibitor KRIBB11 reduced mEHT-induced complement factor 4 (C4) mRNA increase. In conclusion, mEHT monotherapy induced tumor growth inhibition and a complex stress response. Inhibition of this stress response is likely to enhance the effectiveness of mEHT and other cancer treatments.

Complement in Tumourigenesis and the Response to Cancer Therapy

In recent years, our knowledge of the complement system beyond innate immunity has progressed significantly. A modern understanding is that the complement system has a multifaceted role in malignancy, impacting carcinogenesis, the acquisition of a metastatic phenotype and response to therapies. The ability of local immune cells to produce and respond to complement components has provided valuable insights into their regulation, and the subsequent remodeling of the tumour microenvironment. These novel discoveries have advanced our understanding of the immunosuppressive mechanisms supporting tumour growth and uncovered potential therapeutic targets. This review discusses the current understanding of complement in cancer, outlining both direct and immune cell-mediated roles. The role of complement in response to therapies such as chemotherapy, radiation and immunotherapy is also presented. While complement activities are largely context and cancer type-dependent, it is evident that promising therapeutic avenues have been identified, in particular in combination therapies.

"Complimenting the Complement": Mechanistic Insights and Opportunities for Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a leading cause of death in the US and worldwide. HCC remains a global health problem and is highly aggressive with unfavorable prognosis. Even with surgical interventions and newer medical treatment regimens, patients with HCC have poor survival rates. These limited therapeutic strategies and mechanistic understandings of HCC immunopathogenesis urgently warrant non-palliative treatment measures. Irrespective of the multitude etiologies, the liver microenvironment in HCC is intricately associated with chronic necroinflammation, progressive fibrosis, and cirrhosis as precedent events along with dysregulated innate and adaptive immune responses. Central to these immunological networks is the complement cascade (CC), a fundamental defense system inherent to the liver which tightly regulates humoral and cellular responses to noxious stimuli. Importantly, the liver is the primary source for biosynthesis of >80% of complement components and expresses a variety of complement receptors. Recent studies implicate the complement system in liver inflammation, abnormal regenerative responses, fibrosis, carcinogenesis, and development of HCC. Although complement activation differentially promotes immunosuppressive, stimulant, and angiogenic microenvironments conducive to HCC development, it remains under-investigated. Here, we review derangement of specific complement proteins in HCC in the context of altered complement regulatory factors, immune-activating components, and their implications in disease pathogenesis. We also summarize how complement molecules regulate cancer stem cells (CSCs), interact with complement-coagulation cascades, and provide therapeutic opportunities for targeted intervention in HCC.

High Expression of the Component 3a Receptor 1 (C3AR1) Gene in Stomach Adenocarcinomas Infers a Poor Prognosis and High Immune-Infiltration Levels

Background

This study was designed to explore the incompletely investigated role of the complement component 3a receptor 1 (C3AR1) in the prognosis of stomach adenocarcinomas (STAD).

Material/Methods

Using bioinformatic methods, we systematically determined the expression and prognosis value of C3AR1 in various cancers by using the TIMER (Tumor Immune Estimation Resource) database, UALCAN platform, GEPIA (Gene Expression Profiling Interactive Analysis) server, and the OncoLnc tool. The biological processes influenced by C3AR1 were determined using the GSEA (Gene Set Enrichment Analysis) software (Copyright 2004–2020 Broad Institute, Inc., Massachusetts Institute of Technology, and Regents of the University of California). The correlation between C3AR1 expression and the immune-infiltrating cells as well as the correlation analysis between C3AR1 expression and the corresponding immune-marker sets were conducted using the TIMER and GEPIA databases.

Results

The expression of C3AR1 was significantly (P<0.001) differentially expressed on several tumor types, while its prognosis value could only be determined on STAD, with a high expression of C3AR1 closely correlated with a poor prognosis. The GSEA analysis revealed that the differential expression of C3AR1 profoundly affected the immune-related biological processes. The expression of C3AR1 was strongly and positively correlated with the infiltration of monocytes, tumor-associated macrophages, M2 macrophages, dendritic cells, and exhausted T cells.

Conclusions

Our results have revealed that a high expression of C3AR1 is positively correlated with a poor prognosis and increased tumor-immune infiltration. C3AR1 can promote the polarization of M2 macrophages and T cell exhaustion, leading to the immune escape of STAD. These findings suggest that C3AR1 could be used as a prognostic and immune-infiltration marker in the pathogenesis of STAD.

Integrative Analysis of Complement System to Prognosis and Immune Infiltrating in Colon Cancer and Gastric Cancer

Background

The complement system acts as an integral part of the innate immune response, which acts primarily to remove pathogens and injured cells. Emerging evidence has shown the activation of the immune regulatory function of complements in the tumor microenvironment (TME). We revealed the expression levels of various complements in human cancers and their role in tumor prognosis and immune infiltration.

Methods

The differential expression of complements was explored via the Tumor Immune Estimation Resource (TIMER) site and the Oncomine database. To investigate whether these differentially expressed complements have correlation with the prognosis of gastric cancer (GC) and colon cancer, their impact on survival was assessed using the PrognoScan database and Kaplan-Meier plotter. The correlations between complements and tumor immune-infiltrating levels and immune gene markers were statistically explored in TIMER based on Spearman's correlation coefficients and p-values.

Results

In two colon cancer cohorts, an increased expression level of DAF (CD55) has statistically significant correlation with poor disease-free survival (DFS). High C3, CR4, and C5aR1 expression levels were significantly related with poor prognosis in GC patients. In addition, C3, CR4, and C5aR1 expression was positively related to the tumor purity and infiltration levels of multiple immune cells in stomach adenocarcinoma (STAD). Moreover, the expression levels of C3, CR4, and C5aR1 were also strongly correlated with various immune marker sets, such as those of tumor-associated macrophages (TAMs), M1 and M2 macrophages, T cell exhaustion, Tregs, and DCs, in STAD. Additionally, CD55 has positive correlation with few immune cell infiltration levels in colon adenocarcinoma (COAD), but its correlation with immune marker sets was not statistically significant.

Conclusion

These findings confirm the relationship between various complements and tumor prognosis and immune infiltration in colon cancer and GC. CD55 may serve as an indicator on the survival prognosis of patients with colon cancer. Furthermore, as biomarkers for poor prognosis in GC, complements C3, CR4, and C5aR1 may provide potential biological targets for GC immunotherapy.

Effects of Euphorbia umbellata extracts on complement activation and chemotaxis of neutrophils

ETHNOPHARMACOLOGICAL RELEVANCE

The species Euphorbia umbellata (leitosinha) has been traditionally used for the treatment of inflammatory diseases and cancer.

AIM OF THE STUDY

Evaluation the effect of E. umbellata latex extracts obtained with hexane, chloroform, ethyl acetate and methanol on the activation of the complement pathways and neutrophil chemotaxis.

MATERIALS AND METHODS

The latex was partitioned using Soxhlet apparatus and hexane, chloroform, ethyl acetate and methanol as solvents. The classical and alternative pathway activity were performed by hemolytic assays with sensitized sheep or rabbit erythrocytes, respectively; the lectin pathway activity was quantified by ELISA, through the measurement of C4 molecules and the chemotaxis of human neutrophils was performed using 1% casein as the chemotactic inducer and Boyden's chamber. GC-Q-ToF and NMR analyses were applied to evaluate the chemical composition of E. umbellata latex extracts.

RESULTS

All E. umbellata latex extracts exhibited an inhibitory effect on the activation of the alternative pathway. Methanol and ethyl acetate extracts inhibited the classical pathway while chloroform extract activated this pathway. Ethyl acetate and hexane extracts inhibited lectin activation. All E. umbellata extracts inhibited casein-induced neutrophil chemotaxis. Terpenes and phenolic compounds have been suggested to be present in the E. umbellta latex extracts.

CONCLUSION

The E. umbellata latex was able to modulate the functions of the immune system. Thus, it is possible to infer that the terpenes and phenolic compounds of the phytocomplex of E. umbellata latex can contribute for the activity on the complement pathways.

Valproic acid influences the expression of genes implicated with hyperglycaemia-induced complement and coagulation pathways

Because the liver plays a major role in metabolic homeostasis and secretion of clotting factors and inflammatory innate immune proteins, there is interest in understanding the mechanisms of hepatic cell activation under hyperglycaemia and whether this can be attenuated pharmacologically. We have previously shown that hyperglycaemia stimulates major changes in chromatin organization and metabolism in hepatocytes, and that the histone deacetylase inhibitor valproic acid (VPA) is able to reverse some of these metabolic changes. In this study, we have used RNA-sequencing (RNA-seq) to investigate how VPA influences gene expression in hepatocytes. Interesting, we observed that VPA attenuates hyperglycaemia-induced activation of complement and coagulation cascade genes. We also observe that many of the gene activation events coincide with changes to histone acetylation at the promoter of these genes indicating that epigenetic regulation is involved in VPA action.

An Immunoregulatory Role for Complement Receptors in Murine Models of Breast Cancer

The complement system has demonstrated roles in regulating tumor growth, although these may differ between tumor types. The current study used two murine breast cancer models (EMT6 and 4T1) to investigate whether pharmacological targeting of receptors for complement proteins C3a (C3aR) and C5a (C5aR1) is protective in murine breast cancer models. In contrast to prior studies in other tumor models, treatment with the selective C5aR1 antagonist PMX53 had no effect on tumor growth. However, treatment of mice with a dual C3aR/C5aR1 agonist (YSFKPMPLaR) significantly slowed mammary tumor development and progression. Examination of receptor expression by quantitative polymerase chain reaction (qPCR) analysis showed very low levels of mRNA expression for either C3aR or C5aR1 by EMT6 or 4T1 mammary carcinoma cell lines compared with the J774 macrophage line or bone marrow-derived macrophages. Moreover, flow cytometric analysis found no evidence of C3aR or C5aR1 protein expression by either EMT6 or 4T1 cells, leading us to hypothesize that the tumor inhibitory effects of the dual agonist are indirect, possibly via regulation of the anti-tumor immune response. This hypothesis was supported by flow cytometric analysis of tumor infiltrating leukocyte populations, which demonstrated a significant increase in T lymphocytes in mice treated with the C3aR/C5aR1 agonist. These results support an immunoregulatory role for complement receptors in primary murine mammary carcinoma models. They also suggest that complement activation peptides can influence the anti-tumor response in different ways depending on the cancer type, the host immune response to the tumor and levels of endogenous complement activation within the tumor microenvironment.

The Activation of Prothrombin Seems to Play an Earlier Role than the Complement System in the Progression of Colorectal Cancer: A Mass Spectrometry Evaluation

Colorectal cancer (CRC) is the second cause of death in men and the third in women. This work deals with the study of the low molecular weight protein fraction of sera from patients who underwent surgery for CRC and who were followed for several years thereafter. MALDI-TOF MS was used to identify serum peptidome profiles of healthy controls, non-metastatic CRC patients and metastatic CRC patients. A multiple regression model was applied to signals preliminarily selected by SAM analysis to take into account the age and gender differences between the groups. We found that, while a signal m/z 2021.08, corresponding to the C3f fragment of the complement system, appears significantly increased only in serum from metastatic CRC patients, a m/z 1561.72 signal, identified as a prothrombin fragment, has a significantly increased abundance in serum from non-metastatic patients as well. The findings were also validated by a bootstrap resampling procedure. The present results provide the basis for further studies on large cohorts of patients in order to confirm C3f and prothrombin as potential serum biomarkers. Thus, new and non-invasive tests might be developed to improve the classification of colorectal cancer.

Oleic Acid, Cholesterol, and Linoleic Acid as Angiogenesis Initiators

The current study determined the natural angiogenic molecules using an unbiased metabolomics approach. A chick chorioallantoic membrane (CAM) model was used to examine pro- and antiangiogenic molecules, followed by gas chromatography-mass spectrometry (GCMS) analysis. Vessel formation was analyzed quantitatively using the angiogenic index (p < 0.05). At embryonic day one, a white streak or circle area was observed when vessel formation begins. GCMS analysis and database search demonstrated that angiogenesis may initiate when oleic, cholesterol, and linoleic acids increased in the area of angiogenic reactions. The gain of function study was conducted by the injection of cholesterol and oleic acid into a chick embryo to determine the role of each lipid in angiogenesis. We propose that oleic acid, cholesterol, and linoleic acid are natural molecules that set the platform for the initiation stage of angiogenesis before other proteins including the vascular endothelial growth factor, angiopoietin, angiotensin, and erythropoietin join as the angiome in sprout extension and vessel maturation.

Expression Patterns of Immune Genes Reveal Heterogeneous Subtypes of High-Risk Neuroblastoma

High risk neuroblastoma (HR-NB) remains difficult to treat, and its overall survival (OS) is still below 50%. Although HR-NB is a heterogeneous disease, HR-NB patients are currently treated in a similar fashion. Through unsupervised biclustering, we further stratified HR-NB patients into two reproducible and clinically distinct subtypes, including an ultra-high risk neuroblastoma (UHR-NB) and high risk neuroblastoma (HR-NB). The UHR-NB subtype consistently had the worst OS in multiple independent cohorts ( P < 0 . 008 ). Out of 283 neuroblastoma-specific immune genes that were used for stratification, 39 of them were differentiated in UHR-NB, including four upregulated and 35 downregulated, as compared to HR-NB. The four UHR-NB upregulated genes (ADAM22, GAL, KLHL13 and TWIST1) were all upregulated in MYCN amplified neuroblastoma in 5 additional cohorts. TWIST1 and ADAM22 were also positively correlated with cancer stage, while GAL was an independent OS predictor in addition to MYCN and age. Furthermore, we identified 26 commonly upregulated and 311 downregulated genes in UHR-NB from all 4723 immune-related genes. While 43 KEGG pathways with molecular functions were enriched in the downregulated immune-related genes, only the P53 signaling pathway was enriched in the upregulated ones, which suggested that UHR-NB was a TP53 related subtype with reduced immune activities.

A Novel Antitumor Strategy: Simultaneously Inhibiting Angiogenesis and Complement by Targeting VEGFA/PIGF and C3b/C4b

Therapeutic antibodies targeting vascular endothelial growth factor (VEGF) have become a critical regimen for tumor therapy, but the efficacy of monotherapy is usually limited by drug resistance and multiple angiogenic mechanisms. Complement proteins are becoming potential candidates for cancer-targeted therapy based on their role in promoting cancer progression and angiogenesis. However, the antitumor abilities of simultaneous VEGF and complement blockade were unknown. We generated a humanized soluble VEGFR-Fc fusion protein (VID) binding VEGFA/PIGF and a CR1-Fc fusion protein (CID) targeting C3b/C4b. Both VID and CID had good affinities to their ligands and showed effective bioactivities. In vitro, angiogenesis effects induced by VEGF and hemolysis induced by complement were inhibited by VID and CID, respectively. Further, VID and CID confer a synergetic therapeutic effect in a colitis-associated colorectal cancer (CAC) model and an orthotopic 4T1 breast cancer model. Mechanically, combination therapy inhibited tumor angiogenesis, cell proliferation, and MDSC infiltration in the tumor microenvironment and promoted tumor cell apoptosis. Our study offers a novel therapeutic strategy for anti-VEGF-resistant tumors and chronic-inflammation-associated tumors.

Complement C3 overexpression activates JAK2/STAT3 pathway and correlates with gastric cancer progression

Background

Localized C3 deposition is a well-known factor of inflammation. However, its role in oncoprogression of gastric cancer (GC) remains obscured. This study aims to explore the prognostic value of C3 deposition and to elucidate the mechanism of C3-related oncoprogression for GC.

Methods

From August to December 2013, 106 GC patients were prospectively included. The regional expression of C3 and other effectors in gastric tissues were detected by WB, IHC, qRT-PCR and other tests. The correlation of localized C3 deposition and oncologic outcomes was determined by 5-year survival significance. Human GC and normal epithelial cell lines were employed to detect a relationship between C3 and STAT3 signaling pathway in vitro experiments.

Results

C3 and C3a expression were markedly enhanced in GC tissues at both mRNA and protein levels compared with those in paired nontumorous tissues. According to IHC C3 score, 65 (61.3%) and 41 (38.7%) patients had high and low C3 deposition, respectively. C3 deposition was negatively correlated with plasma levels of C3 and C3a (both P < 0.001) and positively correlated with pathological T and TNM stages (both P < 0.001). High C3 deposition was identified as an independent prognostic factor of poor 5-year overall survival (P = 0.045). In vitro C3 administration remarkably enhanced p-JAK2/p-STAT3 expression in GC cell lines but caused a reduction of such activation when pre-incubated with a C3 blocker. Importantly, C3 failed to activate such signaling in cells pre-treated with a JAK2 inhibitor.

Conclusions

Localized C3 deposition in the tumor microenvironment is a relevant immune signature for predicting prognosis of GC. It may aberrantly activate JAK2/STAT3 pathway allowing oncoprogression.

Trial registration

ClinicalTrials.gov, NCT02425930, Registered 1st August 2013.

Mutations in an Innate Immunity Pathway Are Associated with Poor Overall Survival Outcomes and Hypoxic Signaling in Cancer

Complement-mediated cytotoxicity may act as a selective pressure for tumor overexpression of complement regulators. We hypothesize that the same selective pressure could lead to complement alterations at the genetic level. We find that, when analyzed as a pathway, mutations in complement genes occur at a relatively high frequency and are associated with changes in overall survival across a number of cancer types. Analysis of pathways expressed in patients with complement mutations that are associated with poor overall survival reveals crosstalk between complement and hypoxia in colorectal cancer. The importance of this crosstalk is highlighted by two key findings: hypoxic signaling is increased in tumors harboring complement mutations, and hypoxic tumor cells are resistant to complement-mediated cytotoxicity due, in part, to hypoxia-induced expression of complement regulator CD55. The range of strategies employed by tumors to dysregulate the complement system testifies to the importance of this pathway in tumor progression.

Integrating complement into the molecular pathogenesis of Hidradenitis Suppurativa

Complement inhibition has been identified as a potential therapeutic target for multiple inflammatory disorders including Hidradenitis Suppurativa (HS). It is currently unclear how complement integrates into our current model of molecular pathogenesis in HS and whether it represents a central component of pathogenesis, or a neutrophil-associated bystander. Levels of C5a in serum and tissue correlate with disease activity and degree of neutrophilic infiltrates in HS. C5a has been associated with Th17 immune axis activation in psoriasis, rheumatoid arthritis and Crohn's disease with strong similarities to TH17 activation in HS. Porphyromonas species (which are identified in the HS microbiome) are able to cleave inactive C5 into C5a implicating the cutaneous microbiome as an activator of complement. C3a and C5a are associated with activation of the NLRP3 inflammasome, implicated in the inflammatory drive in HS. Complement receptors are present upon dendritic cells, monocytes, fibroblasts and adipocytes, which may broaden the potential contribution of complement to multiple aspects of HS pathogenesis. Dysregulation of complement receptor pathways has been documented in obesity, insulin resistance and polycystic ovarian syndrome leading to the possibility that complement may explain the epidemiological associations between these conditions and HS. The therapeutic potential of complement inhibitors in HS may be related to the therapeutic target (complement receptor or complement subunit) and the presence of alternate receptors (such as C5aR2) or ligands (including C3a, PAMPs and DAMPs). Integrating complement into the known pathogenesis of HS may aid in explaining the contradictory results between Phase 2 studies of C5a antagonists. It also allows for the identification of existing knowledge gaps to target further clinical investigation and research.

Germline variability and tumor expression level of ribosomal protein gene RPL28 are associated with survival of metastatic colorectal cancer patients

This study investigated the potential of single nucleotide polymorphisms as predictors of survival in two cohorts comprising 417 metastatic colorectal cancer (mCRC) patients treated with the FOLFIRI (folinic acid, 5-fluorouracil and irinotecan) regimen. The rs4806668G > T of the ribosomal protein gene RPL28 was associated with shorter progression-free survival and overall survival by 5 and 9 months (P = 0.002), with hazard ratios of 3.36 (P < 0.001) and 3.07 (P = 0.002), respectively. The rs4806668T allele was associated with an increased RPL28 expression in transverse normal colon tissues (n = 246, P = 0.007). RPL28 expression was higher in colorectal tumors compared to paired normal tissues by up to 124% (P < 0.001) in three independent datasets. Metastatic cases with highest RPL28 tumor expression had a reduced survival in two datasets (n = 88, P = 0.009 and n = 56, P = 0.009). High RPL28 was further associated with changes in immunoglobulin and extracellular matrix pathways. Repression of RPL28 reduced proliferation by 1.4-fold to 5.6-fold (P < 0.05) in colon cancer HCT116 and HT-29 cells. Our findings suggest that the ribosomal RPL28 protein may influence mCRC outcome.

Blockade of the Complement C5a/C5aR1 Axis Impairs Lung Cancer Bone Metastasis by CXCL16-mediated Effects

RATIONALE

C5aR1 (CD88), a receptor for complement anaphylatoxin C5a, is a potent immune mediator. Its impact on malignant growth and dissemination of non-small cell lung cancer cells is poorly understood.

OBJECTIVES

To investigate the contribution of the C5a/C5aR1 axis to the malignant phenotype of non-small cell lung cancer cells, particularly in skeletal colonization, a preferential lung metastasis site.

METHODS

Association between C5aR1 expression and clinical outcome was assessed in silico and validated by immunohistochemistry. Functional significance was evaluated by lentiviral gene silencing and ligand l-aptamer inhibition in in vivo models of lung cancer bone metastasis. In vitro functional assays for signaling, migration, invasion, metalloprotease activity, and osteoclastogenesis were also performed.

MEASUREMENTS AND MAIN RESULTS

High levels of C5aR1 in human lung tumors were significantly associated with shorter recurrence-free survival, overall survival, and bone metastasis. Silencing of C5aR1 in lung cancer cells led to a substantial reduction in skeletal metastatic burden and osteolysis in in vivo models. Furthermore, metalloproteolytic, migratory, and invasive tumor cell activities were modulated in vitro by C5aR1 stimulation or gene silencing. l-Aptamer blockade or C5aR1 silencing significantly reduced the osseous metastatic activity of lung cancer cells in vivo. This effect was associated with decreased osteoclastogenic activity in vitro and was rescued by the exogenous addition of the chemokine CXCL16.

CONCLUSIONS

Disruption of C5aR1 signaling in lung cancer cells abrogates their tumor-associated osteoclastogenic activity, impairing osseous colonization. This study unveils the role played by the C5a/C5aR1 axis in lung cancer dissemination and supports its potential use as a novel therapeutic target.

Complement System in Cutaneous Squamous Cell Carcinoma

Epidermal keratinocyte-derived cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer with high mortality rates in the advanced stage. Chronic inflammation is a recognized risk factor for cSCC progression and the complement system, as a part of innate immunity, belongs to the microenvironment of tumors. The complement system is a double-edged sword in cancer, since complement activation is involved in anti-tumor cytotoxicity and immune responses, but it also promotes cancer progression directly and indirectly. Recently, the role of several complement components and inhibitors in the regulation of progression of cSCC has been shown. In this review, we will discuss the role of complement system components and inhibitors as biomarkers and potential new targets for therapeutic intervention in cSCC.

Dual Effects of Chinese Herbal Medicines on Angiogenesis in Cancer and Ischemic Stroke Treatments: Role of HIF-1 Network

Hypoxia-inducible factor-1 (HIF-1)–induced angiogenesis has been involved in numerous pathological conditions, and it may be harmful or beneficial depending on the types of diseases. Exploration on angiogenesis has sparked hopes in providing novel therapeutic approaches on multiple diseases with high mortality rates, such as cancer and ischemic stroke. The HIF-1 pathway is considered to be a major regulator of angiogenesis. HIF-1 seems to be involved in the vascular formation process by synergistic correlations with other proangiogenic factors in cancer and cerebrovascular disease. The regulation of HIF-1–dependent angiogenesis is related to the modulation of HIF-1 bioactivity by regulating HIF-1α transcription or protein translation, HIF-1α DNA binding, HIF-1α and HIF-1α dimerization, and HIF-1 degradation. Traditional Chinese herbal medicines have a long history of clinical use in both cancer and stroke treatments in Asia. Growing evidence has demonstrated potential proangiogenic benefits of Chinese herbal medicines in ischemic stroke, whereas tumor angiogenesis could be inhibited by the active components in Chinese herbal medicines. The objective of this review is to provide comprehensive insight on the effects of Chinese herbal medicines on angiogenesis by regulating HIF-1 pathways in both cancer and ischemic stroke.

Plasma proteome plus site-specific N-glycoprofiling for hepatobiliary carcinomas

Hepatobiliary cancer is the third leading cause of cancer death worldwide. Appropriate markers for early diagnosis, monitoring of disease progression, and prediction of postsurgical outcome are still lacking. As the majority of circulating N‐glycoproteins are originated from the hepatobiliary system, we sought to explore new markers by assessing the dynamics of N‐glycoproteome in plasma samples from patients with hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), or combined HCC and CCA (cHCC‐CCA). Using a mass spectrometry‐based quantitative proteomic approach, we found that 57 of 5358 identified plasma proteins were differentially expressed in hepatobiliary cancers. The levels of four essential proteins, including complement C3 and apolipoprotein C‐III in HCC, galectin‐3‐binding protein in CCA, and 72 kDa inositol polyphosphate 5‐phosphatase in cHCC‐CCA, were highly correlated with tumor stage, tumor grade, recurrence‐free survival, and overall survival. Postproteomic site‐specific N‐glycan analyses showed that human complement C3 bears high‐mannose and hybrid glycoforms rather than complex glycoforms at Asn85. The abundance of complement C3 with mannose‐5 or mannose‐6 glycoform at Asn85 was associated with HCC tumor grade. Furthermore, stepwise Cox regression analyses revealed that HCC patients with a hybrid glycoform at Asn85 of complement C3 had a lower postsurgery tumor recurrence rate or mortality rate than those with a low amount of complement C3 protein. In conclusion, our data show that particular plasma N‐glycoproteins with specific N‐glycan compositions could be potential noninvasive markers to evaluate oncological status and prognosis of hepatobiliary cancers.

The Complement Cascade as a Mediator of Human Malignant Hematopoietic Cell Trafficking

The complement cascade (ComC) cleavage fragments C3a and C5a regulate the trafficking of normal, differentiated hematopoietic cells, although they do not chemoattract more primitive hematopoietic stem/progenitor cells (HSPCs). By contrast, human myeloid and lymphoid leukemia cell lines and clonogenic blasts from chronic myelogenous leukemia (CML) and acute myelogenous leukemia (AML) patients respond to C3 and C5 cleavage fragments by chemotaxis and increased adhesion. Consistent with this finding, C3a and C5a receptors are expressed by leukemic cells at the mRNA (RT-PCR) and protein (FACS) levels, and these cells respond to C3a and C5a stimulation by phosphorylation of p44/42 MAPK and AKT. However, neither of these ComC cleavage fragments have an effect on cell proliferation or survival. In parallel, we found that inducible heme oxygenase 1 (HO-1)-an anti-inflammatory enzyme, is a negative regulator of ComC-mediated trafficking of malignant cells and that stimulation of these cells by C3 or C5 cleavage fragments downregulates HO-1 expression in a p38 MAPK-dependent manner, rendering cells exposed to C3a or C5a more mobile. We propose that, while the ComC is not directly involved in the proliferation of malignant hematopoietic cells, its activation in leukemia/lymphoma patients (e.g., as a result of accompanying infections or sterile inflammation after radio-chemotherapy) enhances the motility of malignant cells and contributes to their dissemination in a p38 MAPK-HO-1 axis-dependent manner. Based on this idea, we propose that inhibition of p38 MAPK or upregulation of HO-1 by available small-molecule modulators would have a beneficial effect on ameliorating expansion and dissemination of leukemia/lymphoma cells in clinical situations in which the ComC becomes activated. Finally, since we detected expression of C3 and C5 mRNA in human leukemic cell lines, further study of the potential role of the complosome in regulating the behavior of these cells is needed.

Targeting the Complement Pathway as a Therapeutic Strategy in Lung Cancer

Lung cancer is the leading cause of cancer death in men and women. Lung adenocarcinoma (LUAD), represents approximately 40% of all lung cancer cases. Advances in recent years, such as the identification of oncogenes and the use of immunotherapies, have changed the treatment of LUAD. Yet survival rates still remain low. Additionally, there is still a gap in understanding the molecular and cellular interactions between cancer cells and the immune tumor microenvironment (TME). Defining how cancer cells with distinct oncogenic drivers interact with the TME and new strategies for enhancing anti-tumor immunity are greatly needed. The complement cascade, a central part of the innate immune system, plays an important role in regulation of adaptive immunity. Initially it was proposed that complement activation on the surface of cancer cells would inhibit cancer progression via membrane attack complex (MAC)-dependent killing. However, data from several groups have shown that complement activation promotes cancer progression, probably through the actions of anaphylatoxins (C3a and C5a) on the TME and engagement of immunoevasive pathways. While originally shown to be produced in the liver, recent studies show localized complement production in numerous cell types including immune cells and tumor cells. These results suggest that complement inhibitory drugs may represent a powerful new approach for treatment of NSCLC, and numerous new anti-complement drugs are in clinical development. However, the mechanisms by which complement is activated and affects tumor progression are not well understood. Furthermore, the role of local complement production vs. systemic activation has not been carefully examined. This review will focus on our current understanding of complement action in LUAD, and describe gaps in our knowledge critical for advancing complement therapy into the clinic.

Immune Cell Metabolism in Tumor Microenvironment

Tumor microenvironment (TME) is composed of tumor cells, immune cells, cytokines, extracellular matrix, etc. The immune system and the metabolisms of glucose, lipids, amino acids, and nucleotides are integrated in the tumorigenesis and development. Cancer cells and immune cells show metabolic reprogramming in the TME, which intimately links immune cell functions and edits tumor immunology. Recent findings in immune cell metabolism hold the promising possibilities toward clinical therapeutics for treating cancer. This chapter introduces the updated understandings of metabolic reprogramming of immune cells in the TME and suggests new directions in manipulation of immune responses for cancer diagnosis and therapy.

Complementing the Cancer-Immunity Cycle

Reactivation of cytotoxic CD8+ T-cell responses has set a new direction for cancer immunotherapy. Neutralizing antibodies targeting immune checkpoint programmed cell death protein 1 (PD-1) or its ligand (PD-L1) have been particularly successful for tumor types with limited therapeutic options such as melanoma and lung cancer. However, reactivation of T cells is only one step toward tumor elimination, and a substantial fraction of patients fails to respond to these therapies. In this context, combination therapies targeting more than one of the steps of the cancer-immune cycle may provide significant benefits. To find the best combinations, it is of upmost importance to understand the interplay between cancer cells and all the components of the immune response. This review focuses on the elements of the complement system that come into play in the cancer-immunity cycle. The complement system, an essential part of innate immunity, has emerged as a major regulator of cancer immunity. Complement effectors such as C1q, anaphylatoxins C3a and C5a, and their receptors C3aR and C5aR1, have been associated with tolerogenic cell death and inhibition of antitumor T-cell responses through the recruitment and/or activation of immunosuppressive cell subpopulations such as myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), or M2 tumor-associated macrophages (TAMs). Evidence is provided to support the idea that complement blocks many of the effector routes associated with the cancer-immunity cycle, providing the rationale for new therapeutic combinations aimed to enhance the antitumor efficacy of anti-PD-1/PD-L1 checkpoint inhibitors.

The transcriptional profile of circulating myeloid derived suppressor cells correlates with tumor development and progression in mouse

Myeloid derived suppressor cells (MDSCs) play key roles in cancer development. Accumulation of peripheral-blood MDSCs (PB-MDSCs) corresponds to the progression of various cancers, but provides only a crude indicator. We aimed toward identifying changes in the transcriptional profile of PB-MDSCs in response to tumor growth. CT26 colon cancer cells and B16 melanoma cells (10⁶) were inoculated into peritoneal cavities of BALB/c mice and subcutaneously to C57-black mice, respectively. The circulating levels and global transcriptional patterns of PB CD11b⁺Ly6g⁺ MDSCs were assessed in control mice, and 4, 8, and 11 days following tumor cell inoculation. Although a significant accumulation of PB-MDSCs was demonstrated only 11 days following tumor induction, a pronounced transcriptional response was identified already on day 4 while the tumor was ~1 mm in size. Further transcriptional changes correlated with different stages of tumor growth. Key MDSC genes and canonical signaling pathways were activated along tumor progression. This phenomenon was demonstrated in both cancer models, and a consensus set of 817 genes, involved in myeloid cell recruitment and angiogenesis, was identified. The data suggest that the transcriptional signatures of PB-MDSC may serve as markers for tumor progression, as well as providing potential targets for future therapies.

CFP suppresses breast cancer cell growth by TES-mediated upregulation of the transcription factor DDIT3

Breast cancer is a heterogeneous genetic disease driven by the accumulation of individual mutations per tumor. Whole-genome sequencing approaches have identified numerous genes with recurrent mutations in primary tumors. Although mutations in well characterized tumor suppressors and oncogenes are overrepresented in these sets, the majority of the genetically altered genes have so far unknown roles in breast cancer progression. To improve the basic understanding of the complex disease breast cancer and to potentially identify novel drug targets or regulators of known cancer-driving pathways, we analyzed 86 wild-type genes and 94 mutated variants for their effect on cell growth using a serially constructed panel of MCF7 cell lines. We demonstrate in subsequent experiments that the metal cation transporter CNNM4 regulates growth by induction of apoptosis and identified a tumor suppressive role of complement factor properdin (CFP) in vitro and in vivo. CFP appears to induce the intracellular upregulation of the pro-apoptotic transcription factor DDIT3 which is associated with endoplasmic reticulum-stress response.

MALDI-TOF-MS Analysis in the Identification of Urine Proteomic Patterns of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) is a group of highly aggressive, rare tumors. Human chorionic gonadotropin is a common biomarker used in the diagnosis and monitoring of GTD. To improve our knowledge of the pathology of GTD, we performed protein-peptide profiling on the urine of patients affected with gestational trophoblastic neoplasm (GTN). We analyzed urine samples from patients diagnosed with GTN (n = 26) and from healthy pregnant and non-pregnant controls (n = 17) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Ions were examined in a linear mode over a m/z range of 1000–10,000. All GTN urine samples were analyzed before and after treatment and compared with those of the controls. The statistical analyses included multivariate classification algorithms as well as ROC curves. Urine sample analyses revealed there were significant differences in the composition of the ions between the evaluated groups. Comparing the pre-treatment and group with the pregnant controls, we identified two discriminatory proteins: hemoglobin subunit α (m/z = 1951.81) and complement C4A (m/z = 1895.43). Then, comparing urine samples from the post-treatment cases with those from the non-pregnant controls, we identified the peptides uromodulin fragments (m/z = 1682.34 and 1913.54) and complement C4A (m/z = 1895.43).

Expression of complement C3, C5, C3aR and C5aR1 genes in resting and activated CD4+ T cells

Complement activation is traditionally thought to occur in the extracellular space. However, it has been suggested that complement proteins are activated and function at additional locations. T cells contain intracellular stores of C3 and C5 that can be cleaved into C3a and C5a and bind to intracellular receptors, which have been shown to be of vital importance for the differentiation and function of these cells. However, whether the origin of the complement proteins located within T cells is derived from endogenous produced complement or from an uptake dependent mechanism is unknown. The presence of intracellular C3 in T cells from normal donors was investigated by fluorescence microscopy and flow cytometry. Moreover, mRNA expression levels of several genes encoding for complement proteins with primary focus on C3, C3aR, C5 and C5aR1 during resting state and upon activation of CD4⁺ T cells were investigated by a quantitative PCR technique. Furthermore, the gene expression level was evaluated at different time points. We confirmed the presence of intracellular C3 protein in normal T-cells. However, we could not see any increase in mRNA levels using any activation strategy tested. On the contrary, we observed a slight increase in C3 and C5aR1 mRNA only in the non-activated T-cells compared to the activated T cells, and a decrease in the activated T-cells at different incubation time points. Our results show that there is a baseline intracellular expression of the complement C3, C5, C3aR and C5aR1 genes in normal CD4⁺ T cells, but that expression is not increased during T-cell activation, but rather down regulated. Thus, the pool of intracellular complement in CD4⁺ T cells may either be due to accumulated complement due low-grade expression or arise from the circulation from an uptake dependent mechanism, but these possibilities are not mutually exclusive.

Distinct urinary glycoprotein signatures in prostate cancer patients

Novel biomarkers are needed to complement prostate specific antigen (PSA) in prostate cancer (PCa) diagnostic screening programs. Glycoproteins represent a hitherto largely untapped resource with a great potential as specific and sensitive tumor biomarkers due to their abundance in bodily fluids and their dynamic and cancer-associated glycosylation. However, quantitative glycoproteomics strategies to detect potential glycoprotein cancer markers from complex biospecimen are only just emerging. Here, we describe a glycoproteomics strategy for deep quantitative mapping of N- and O-glycoproteins in urine with a view to investigate the diagnostic value of the glycoproteome to discriminate PCa from benign prostatic hyperplasia (BPH), two conditions that remain difficult to clinically stratify. Total protein extracts were obtained, concentrated and digested from urine of six PCa patients (Gleason score 7) and six BPH patients. The resulting peptide mixtures were TMT-labeled and mixed prior to a multi-faceted sample processing including hydrophilic interaction liquid chromatography (HILIC) and titanium dioxide SPE based enrichment, endo-/exoglycosidase treatment and HILIC-HPLC pre-fractionation. The isolated N- and O-glycopeptides were detected and quantified using high resolution mass spectrometry. We accurately quantified 729 N-glycoproteins spanning 1,310 unique N-glycosylation sites and observed 954 and 965 unique intact N- and O-glycopeptides, respectively, across the two disease conditions. Importantly, a panel of 56 intact N-glycopeptides perfectly discriminated PCa and BPH (ROC: AUC = 1). This study has generated a panel of intact glycopeptides that has a potential for PCa detection.

Identification of complement inhibitory activities of two chemotherapeutic agents using a high-throughput cell imaging-based screening assay

Excessive complement activation contributes significantly to the pathogeneses of various diseases. Currently, significant developmental research efforts aim to identify complement inhibitors with therapeutic uses have led to the approval of one inhibitor for clinical use. However, most existing complement inhibitors are based on monoclonal antibodies, which have many drawbacks such as high costs and limited administration options. With this report, we establish an inexpensive, cell imaging-based high-throughput assay for the large-scale screening of potential small molecule complement inhibitors. Using this assay, we screened a library containing 3115 bioactive chemical compounds and identified cisplatin and pyridostatin as two new complement inhibitors in addition to nafamostat mesylate, a compound with known complement inhibitory activity. We further demonstrated that cisplatin and pyridostatin inhibit C5 convertases in the classical pathway of complement activation but have no effects on the alternative pathway of complement activation. In summary, this work has established a simple, large-scale, high-throughput assay for screening novel complement inhibitors and discovered previously unknown complement activation inhibitory activities for cisplatin and pyridostatin.

Complement system's role in cancer and its therapeutic potential in ovarian cancer

Cancer immunotherapy is a strong candidate for the long-awaited new edition to standard cancer therapies. For an effective immunotherapy, it is imperative to delineate the players of antitumour immune response. As an important innate immune system effector mechanism, complement is highly likely to play a substantial role in cancer immunity. Studies suggest that there may be two different "states of complement" that show opposing effects on cancer cells; a complement profile that has antitumour effects with low expression of membrane-bound complement regulator proteins (mCRPs), lytic membrane attack complex (MAC) concentration and moderate C5a concentration, and a complement profile that has protumour effects with high expression of mCRPs, sublytic MAC and high concentrations of C5a. One of the cancers that urgently require innovative therapeutic approaches is ovarian cancer, and complement has a potential to be a good target for this purpose. A combinatorial approach where the complement cascade is fine-tuned by inhibiting some of its activities while promoting the others can prove to be a fruitful approach. Herein, we will briefly discuss the cancer-immune system interaction and then present a discussion of complement system's role in tumour immunity and its therapeutic potential for ovarian cancer immunotherapy.

The tumour microenvironment links complement system dysregulation and hypoxic signalling

The complement system is an innate immune pathway typically thought of as part of the first line of defence against “non-self” species. In the context of cancer, complement has been described to have an active role in facilitating cancer-associated processes such as increased proliferation, angiogenesis and migration. Several cellular members of the tumour microenvironment express and/or produce complement proteins locally, including tumour cells. Dysregulation of the complement system has been reported in numerous tumours and increased expression of complement activation fragments in cancer patient specimens correlates with poor patient prognosis. Importantly, genetic or pharmacological targeting of complement has been shown to reduce tumour growth in several cancer preclinical models, suggesting that complement could be an attractive therapeutic target. Hypoxia (low oxygen) is frequently found in solid tumours and has a profound biological impact on cellular and non-cellular components of the tumour microenvironment. In this review, we focus on hypoxia since this is a prevailing feature of the tumour microenvironment that, like increased complement, is typically associated with poor prognosis. Furthermore, interesting links between hypoxia and complement have been recently proposed but never collectively reviewed. Here, we explore how hypoxia alters regulation of complement proteins in different cellular components of the tumour microenvironment, as well as the downstream biological consequences of this regulation.

Pleiotropic Effects of Risk Factors in Age-Related Macular Degeneration and Seemingly Unrelated Complex Diseases

Age-related macular degeneration (AMD) is a complex disease with both environmental and genetic factors influencing disease risk. Genome-wide case-control association studies, candidate gene analyses, and epidemiological studies reinforced the notion that AMD is predominantly a disease of an impaired complement system and an altered high-density lipoprotein (HDL) metabolism. Recent reports demonstrated the pleiotropic role of the complement system and HDL in complex diseases such as cardiovascular disease, autoimmune disorders, cancer, and Alzheimer's disease. In light of these findings, we explore current evidence for a shared genetic and environmental risk of AMD and unrelated complex diseases based on epidemiological studies. Shared risk factors may indicate common pathways in disease pathology and thus may have implications for novel treatment options of AMD pathology.

Betulin-3,28-diphosphate as a Component of Combination Cytostatic Drugs for the Treatment of Ehrlich Ascites Carcinoma In Vitro and In Vivo Experiments

The activity of betulin-3,28-diphosphate (BDP) in combination with the cytostatics such as 5-fluorouracil (5-FU) and hydrazine sulfate (HS) was demonstrated by using the transplanted Ehrlich ascites carcinoma (EAC) in mice. The dose-dependent effect of combination drugs BDP + HS and BDP + 5-FU was revealed by in vitro experiments on rats. The synergetic effect of HS and BDP on oxidative stress and energy metabolism was established. The malonic dialdehyde (MDA) level both in plasma and erythrocytes decreased by 87 ± 2%, and the superoxide dismutase (SOD) activity increased by 105 ± 7% in comparison with the control. The combination of BDP + HS promoted the increase of lactate dehydrogenase (LDH) activity in the reverse reaction by 195 ± 21% compared to the control. The combination drug of 5-FU with BDP caused the synergetic decrease of the lipid peroxidation (LPO) intensity estimated by the MDA level decrease up to 14 ± 4% compared to pure compounds. Betulin-3,28-diphosphate in combination with cytostatics for EAC treatment improved the animal health status, as well as decreased the cytostatics dose that can be used in palliative therapy.