Complement as a Biological Tool to Control Tumor Growth

C5AR1-induced TLR1/2 pathway activation drives proliferation and metastasis in anaplastic thyroid cancer

This study aimed to elucidate the role and mechanisms of Complement C5a receptor 1 (C5AR1) in driving the malignant progression of anaplastic thyroid carcinoma (ATC). C5AR1 expression was assessed in ATC tissues and cell lines. Functional assays evaluated the effects of C5AR1 knockdown on the malignant features of ATC cells. The interaction between C5AR1 and miR-335-5p was confirmed using a luciferase reporter assay and Fluorescence in situ hybridization, and the impact of C5AR1 knockdown on the Toll-like receptor (TLR) 1/2 signaling pathway was examined. In vivo studies evaluated the effects of C5AR1 modulation on tumor growth and metastasis. C5AR1 levels were elevated in ATC tumor samples and associated with poor survival in ATC patients. C5AR1 knockdown impeded ATC cell proliferation, migration, and invasion in vitro. MiR-335-5p was identified as an upstream regulator of C5AR1, which negatively modulates C5AR1 expression. C5AR1 knockdown diminished TLR1, TLR2, and myeloid differentiation primary response 88 (MyD88) levels, while C5AR1 overexpression activated this pathway. Blocking TLR1/2 signaling abrogated the oncogenic effects of C5AR1 overexpression. C5AR1 silencing inhibited tumor growth and lung metastasis of ATC cells in nude mice. C5AR1 contributes to ATC tumorigenesis and metastasis by activating the TLR1/2 pathway, and is negatively regulated by miR-335-5p. Targeting the miR-335-5p/C5AR1/TLR1/2 axis represents a potential therapeutic strategy for ATC.

Recent Findings on Therapeutic Cancer Vaccines: An Updated Review

Cancer remains one of the global leading causes of death and various vaccines have been developed over the years against it, including cell-based, nucleic acid-based, and viral-based cancer vaccines. Although many vaccines have been effective in in vivo and clinical studies and some have been FDA-approved, there are major limitations to overcome: (1) developing one universal vaccine for a specific cancer is difficult, as tumors with different antigens are different for different individuals, (2) the tumor antigens may be similar to the body's own antigens, and (3) there is the possibility of cancer recurrence. Therefore, developing personalized cancer vaccines with the ability to distinguish between the tumor and the body's antigens is indispensable. This paper provides a comprehensive review of different types of cancer vaccines and highlights important factors necessary for developing efficient cancer vaccines. Moreover, the application of other technologies in cancer therapy is discussed. Finally, several insights and conclusions are presented, such as the possibility of using cold plasma and cancer stem cells in developing future cancer vaccines, to tackle the major limitations in the cancer vaccine developmental process.

Therapy-induced senescent cancer cells exhibit complement activation and increased complement regulatory protein expression

Therapy-induced senescence (TIS) is a primary response to chemotherapy, contributing to untoward treatment outcomes such as evasion of immunosurveillance. Despite the established role of the complement system in the immune response to cancer, the role of complement in mediating the immune response against senescent tumor cells remains poorly understood. To explore this relationship, we exposed lung adenocarcinoma (A549), breast adenocarcinoma (MCF7) and pancreatic carcinoma (Panc-1) cell lines to sublethal doses of either etoposide or doxorubicin to trigger TIS. Identification of TIS was based on morphological changes, upregulation of the senescence-associated β-galactosidase, p21Cip1 induction and lamin B1 downregulation. Using immunofluorescence microscopy, quantitative PCR, ELISA of conditioned media and in silico analysis, we investigated complement activation, complement protein expression, C3 levels in the conditioned media of senescent cells and secreted complement proteins as part of the senescence-associated secretory phenotype (SASP), respectively. In cell lines undergoing TIS, complement-related changes included (i) activation of the terminal pathway, evidenced by the deposition of C5b-9 on senescent cells; (ii) an increase in the expression of CD59 and complement factor H and (iii) in A549 cells, an elevation in the expression of C3 with its secretion into the medium. In addition, increased C3 expression was observed in breast cancer samples expressing TIS hallmarks following exposure to neoadjuvant chemotherapy. In conclusion, TIS led to the activation of complement, upregulation of complement regulatory proteins and increased C3 expression. Complement appears to play a role in shaping the cancer microenvironment upon senescence induction.

The Yin Yang of Complement and Cancer

Cancer-related inflammation is a crucial component of the tumor microenvironment (TME). Complement activation occurs in cancer and supports the development of an inflammatory microenvironment. Complement has traditionally been considered a mechanism of immune resistance against cancer, and its activation is known to contribute to the cytolytic effects of antibody-based immunotherapeutic treatments. However, several studies have recently revealed that complement activation may exert protumoral functions by sustaining cancer-related inflammation and immunosuppression through different molecular mechanisms, targeting both the TME and cancer cells. These new discoveries have revealed that complement manipulation can be considered a new strategy for cancer therapies. Here we summarize our current understanding of the mechanisms by which the different elements of the complement system exert antitumor or protumor functions, both in preclinical studies and in human tumorigenesis. Complement components can serve as disease biomarkers for cancer stratification and prognosis and be exploited for tumor treatment.

A novel complement-fixing IgM antibody targeting GPC1 as a useful immunotherapeutic strategy for the treatment of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a very low survival rate at 5 years. The use of chemotherapeutic agents results in only modest prolongation of survival and is generally associated with the occurrence of toxicity effects. Antibody-based immunotherapy has been proposed for the treatment of PDAC, but its efficacy has so far proved limited. The proteoglycan glypican-1 (GPC1) may be a useful immunotherapeutic target because it is highly expressed on the surface of PDAC cells, whereas it is not expressed or is expressed at very low levels in benign neoplastic lesions, chronic pancreatitis, and normal adult tissues. Here, we developed and characterized a specific mouse IgM antibody (AT101) targeting GPC1.

METHODS

We developed a mouse monoclonal antibody of the IgM class directed against an epitope of GPC1 in close proximity to the cell membrane. For this purpose, a 46 amino acid long peptide of the C-terminal region was used to immunize mice by an in-vivo electroporation protocol followed by serum titer and hybridoma formation.

RESULTS

The ability of AT101 to bind the GPC1 protein was demonstrated by ELISA, and by flow cytometry and immunofluorescence analysis in the GPC1-expressing "PDAC-like" BXPC3 cell line. In-vivo experiments in the BXPC3 xenograft model showed that AT101 was able to bind GPC1 on the cell surface and accumulate in the BXPC3 tumor masses. Ex-vivo analyses of BXPC3 tumor masses showed that AT101 was able to recruit immunological effectors (complement system components, NK cells, macrophages) to the tumor site and damage PDAC tumor tissue. In-vivo treatment with AT101 reduced tumor growth and prolonged survival of mice with BXPC3 tumor (p < 0.0001).

CONCLUSIONS

These results indicate that AT101, an IgM specific for an epitope of GPC1 close to PDAC cell surface, is a promising immunotherapeutic agent for GPC1-expressing PDAC, being able to selectively activate the complement system and recruit effector cells in the tumor microenvironment, thus allowing to reduce tumor mass growth and improve survival in treated mice.

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.

A comprehensive overview on antibody-drug conjugates: from the conceptualization to cancer therapy

Antibody-Drug Conjugates (ADCs) represent an innovative class of potent anti-cancer compounds that are widely used in the treatment of hematologic malignancies and solid tumors. Unlike conventional chemotherapeutic drug-based therapies, that are mainly associated with modest specificity and therapeutic benefit, the three key components that form an ADC (a monoclonal antibody bound to a cytotoxic drug via a chemical linker moiety) achieve remarkable improvement in terms of targeted killing of cancer cells and, while sparing healthy tissues, a reduction in systemic side effects caused by off-tumor toxicity. Based on their beneficial mechanism of action, 15 ADCs have been approved to date by the market approval by the Food and Drug Administration (FDA), the European Medicines Agency (EMA) and/or other international governmental agencies for use in clinical oncology, and hundreds are undergoing evaluation in the preclinical and clinical phases. Here, our aim is to provide a comprehensive overview of the key features revolving around ADC therapeutic strategy including their structural and targeting properties, mechanism of action, the role of the tumor microenvironment and review the approved ADCs in clinical oncology, providing discussion regarding their toxicity profile, clinical manifestations and use in novel combination therapies. Finally, we briefly review ADCs in other pathological contexts and provide key information regarding ADC manufacturing and analytical characterization.

Interactions between MFAP5 + fibroblasts and tumor-infiltrating myeloid cells shape the malignant microenvironment of colorectal cancer

BACKGROUND

The therapeutic targeting of the tumor microenvironment (TME) in colorectal cancer (CRC) has not yet been fully developed and utilized because of the complexity of the cell-cell interactions within the TME. The further exploration of these interactions among tumor-specific clusters would provide more detailed information about these communication networks with potential curative value.

METHODS

Single-cell RNA sequencing, spatial transcriptomics, and bulk RNA sequencing datasets were integrated in this study to explore the biological properties of MFAP5 + fibroblasts and their interactions with tumor-infiltrating myeloid cells in colorectal cancer. Immunohistochemistry and multiplex immunohistochemistry were performed to confirm the results of these analyses.

RESULTS

We profiled heterogeneous single-cell landscapes across 27,414 cells obtained from tumors and adjacent tissues. We mainly focused on the pro-tumorigenic functions of the identified MFAP5 + fibroblasts. We demonstrated that tumor-resident MFAP5 + fibroblasts and myeloid cells (particularly C1QC + macrophages) were positively correlated in both spatial transcriptomics and bulk RNA-seq public cohorts. These cells and their interactions might shape the malignant behavior of CRC. Intercellular interaction analysis suggested that MFAP5 + fibroblasts could reciprocally communicate with C1QC + macrophages and other myeloid cells to remodel unfavorable conditions via MIF/CD74, IL34/CSF1R, and other tumor-promoting signaling pathways.

CONCLUSION

Our study has elucidated the underlying pro-tumor mechanisms of tumor-resident MFAP5 + fibroblasts and provided valuable targets for the disruption of their properties.

Combined anti-C1-INH and radiotherapy against glioblastoma

BACKGROUND

A more effective immune response against glioblastoma is needed in order to achieve better tumor control. Radiotherapy can induce anti-tumor mediated immune reactions, in addition to its dose response effects. The complement system can function as a bridge between innate and adaptive immune responses. Combining radiotherapy and complement activating therapy is theoretically interesting.

METHODS

Radiotherapy at 8 Gy × 2 was combined with treatment against C1-inhibitor (C1-INH), a potent inhibitor of activation of the classical pathway of the complement system. Anti-C1-INH was delivered as intratumoral injections. Fully immunocompetent Fischer 344 rats with NS1 glioblastoma tumors were treated. Survival was monitored as primary outcome. Models with either intracranial or subcutaneous tumors were evaluated separately.

RESULTS

In the intracranial setting, irradiation could prolong survival, but there was no additional survival gain as a result of anti-C1-INH treatment. In animals with subcutaneous tumors, combined radio-immunotherapy with anti-C1-INH and irradiation at 8 Gy × 2 significantly prolonged survival compared to control animals, whereas irradiation or anti-C1-INH treatment as single therapies did not lead to significantly increased survival compared to control animals.

CONCLUSIONS

Anti-C1-INH treatment could improve the efficacy of irradiation delivered at sub-therapeutic doses and delay tumor growth in the subcutaneous tumor microenvironment. In the intracranial setting, the doses of anti-C1-INH were not enough to achieve any survival effect in the present setting.

Biological Features of Nanoparticles: Protein Corona Formation and Interaction with the Immune System

Nanoparticles (NPs) are versatile candidates for nanomedical applications due to their unique physicochemical properties. However, their clinical applicability is hindered by their undesirable recognition by the immune system and the consequent immunotoxicity, as well as their rapid clearance in vivo. After injection, NPs are usually covered with layers of proteins, called protein coronas (PCs), which alter their identity, biodistribution, half-life, and efficacy. Therefore, the characterization of the PC is for in predicting the fate of NPs in vivo. The aim of this review was to summarize the state of the art regarding the intrinsic factors closely related to the NP structure, and extrinsic factors that govern PC formation in vitro. In addition, well-known opsonins, including complement, immunoglobulins, fibrinogen, and dysopsonins, such as histidine-rich glycoprotein, apolipoproteins, and albumin, are described in relation to their role in NP detection by immune cells. Particular emphasis is placed on their role in mediating the interaction of NPs with innate and adaptive immune cells. Finally, strategies to reduce PC formation are discussed in detail.

Comprehensive Characterizations of Immune Receptor Repertoire in Tumors and Cancer Immunotherapy Studies

We applied our computational algorithm TRUST4 to assemble immune receptor (T-cell receptor/B-cell receptor) repertoires from approximately 12,000 RNA sequencing samples from The Cancer Genome Atlas and seven immunotherapy studies. From over 35 million assembled complete complementary-determining region 3 sequences, we observed that the expression of CCL5 and MZB1 is the most positively correlated genes with T-cell clonal expansion and B-cell clonal expansion, respectively. We analyzed amino acid evolution during B-cell receptor somatic hypermutation and identified tyrosine as the preferred residue. We found that IgG1+IgG3 antibodies together with FcRn were associated with complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity or phagocytosis. In addition to B-cell infiltration, we discovered that B-cell clonal expansion and IgG1+IgG3 antibodies are also correlated with better patient outcomes. Finally, we created a website, VisualizIRR, for users to interactively explore and visualize the immune repertoires in this study. See related Spotlight by Liu and Han, p. 786.

Immune Phenomena in Myeloid Neoplasms: An "Egg or Chicken" Question

Immune phenomena are increasingly reported in myeloid neoplasms, and include autoimmune cytopenias/diseases and immunodeficiency, either preceding or complicating acute myeloid leukemia, myelodysplastic syndromes (MDS), chronic myeloproliferative neoplasms, and bone marrow failure (BMF) syndromes. Autoimmunity and immunodeficiency are the two faces of a dysregulated immune tolerance and surveillance and may result, along with contributing environmental and genetic factors, in an increased incidence of both tumors and infections. The latter may fuel both autoimmunity and immune activation, triggering a vicious circle among infections, tumors and autoimmune phenomena. Additionally, alterations of the microbiota and of mesenchymal stem cells (MSCs) pinpoint to the importance of a permissive or hostile microenvironment for tumor growth. Finally, several therapies of myeloid neoplasms are aimed at increasing host immunity against the tumor, but at the price of increased autoimmune phenomena. In this review we will examine the epidemiological association of myeloid neoplasms with autoimmune diseases and immunodeficiencies, and the pivotal role of autoimmunity in the pathogenesis of MDS and BMF syndromes, including the paroxysmal nocturnal hemoglobinuria conundrum. Furthermore, we will briefly examine autoimmune complications following therapy of myeloid neoplasms, as well as the role of MSCs and microbiota in these settings.

Laryngeal Squamous Cell Carcinoma: Potential Molecular Mechanism and Prognostic Signature Based on Immune-Related Genes

BACKGROUND Immune-related genes (IRGs) are closely related to the incidence and progression of tumors, potentially indicating that IRGs play an important role in laryngeal squamous cell carcinoma (LSCC). MATERIAL AND METHODS An RNA sequencing dataset containing 123 samples was collected from The Cancer Genome Atlas. Based on immune-related differentially expressed genes (IRDEGs), a potential molecular mechanism of LSCC was explored through analysis of information in the Gene Ontology (GO) resource and the Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interactions (PPIs). A regulatory network of transcriptional regulators and IRDEGs was constructed to explore the underlying molecular mechanism of LSCC at the upstream level. Candidates from IRDEGs for signature were screened via univariate Cox analysis and using the least absolute shrinkage and selection operator (LASSO) technique. The IRDEG signature of LSCC was constructed by using a multivariate Cox proportional hazards model. RESULTS GO and KEGG analysis showed that IRDEGs may participate in the progression of LSCC through immune-related reactions. PPI analysis demonstrated that, among the IRDEGs in LSCC, the Kininogen 1; C-X-X motif chemokine ligand 10; elastase, neutrophil expressed; and LYZ genes are hub genes in the development of LSCC. At the upstream level, SPI1, SP140, signal transducer and activator of transcription 4, zinc finger E-box binding homeobox, and Ikaros family zinc finger 2 are the hub transcriptional regulators of IRDEGs. The risk score based on the IRDEG signature was able to distinguish prognosis in patients with LSCC and represents an independent prognostic risk factor for LSCC. CONCLUSIONS From the perspective of IRGs, we first constructed an IRDEG signature related to the prognosis of LSCC, which can be used as a novel marker to predict prognosis in patients with LSCC.

In vitro functional characterization of biosimilar therapeutic antibodies

The key factor in successful development and marketing of biosimilar antibodies is a deep understanding of their critical quality attributes and the ability to control them. Comprehensive functional characterization is therefore at the heart of the process and is a crucial part of regulatory requirements. Establishment of a scientifically sound molecule-specific functional in vitro assay panel requires diligent planning and high flexibility in order to respond to both regulatory requirements and the ever-changing demands relevant to the different stages of the development and production process. Relevance of the chosen assays to the in vivo mechanism of action is of key importance to the stepwise evidence-based demonstration of biosimilarity. Use of a sound interdisciplinary approach and orthogonal state-of-the-art techniques is also unavoidable for gaining in-depth understanding of the biosimilar candidate. The aim of the present review is to give a snapshot on the methodic landscape as depicted by the available literature discussing the in vitro techniques used for the functional characterization of approved biosimilar therapeutic antibodies. Emerging hot topics of the field and relevant structure-function relationships are also highlighted.

Multivalent Antibody-Recruiting Macromolecules: Linking Increased Binding Affinity with Enhanced Innate Immune Killing

Antibody-recruiting molecules (ARMs) are a novel class of immunotherapeutics. They are capable of introducing antibodies onto disease-relevant targets such as cancer cells, bacterial cells or viruses. This can induce antibody-mediated immune responses such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and antibody-dependent phagocytosis (ADCP), which can kill the pathogen. In contrast to the classic ARMs, multivalent ARMs could offer the advantage of increasing the efficiency of antibody recruitment and subsequent innate immune killing. Such compounds consist of multiple target-binding termini (TBT) and/or antibody-binding termini (ABT). Those multivalent interactions are able to convert low binding affinities into increased binding avidities. This minireview summarizes the current status of multivalent ARMs and gives insight into possible benefits, hurdles still to be overcome and future perspectives.

Autoantibodies specific for C1q, C3b, β2-glycoprotein 1 and annexins may amplify complement activity and reduce apoptosis-mediated immune suppression

Neoplastic cells hijack cell death pathways to evade the immune response. Phosphatidylserine, a marker of apoptotic cells, and its highly conserved bridging proteins, annexins and β2-glycoprotein I, facilitate the efficient removal of apoptotic and necrotic cells via tumor-associated phagocytes in a process called efferocytosis. Efferocytosis results in the clearance of dead and dying cells and local immune suppression. Neoplastic cells also have an increased capacity to activate complement. Complement may facilitate the silent removal of tumor cells and has a dual role in promoting and inhibiting tumor growth. Here I hypothesize that immune response-generating IgG autoantibodies that recognize opsonizing fragments C1q, C3b, and phosphatidylserine-binding proteins (annexins, β2-glycoprotein I) may reduce tumor growth. I propose that these autoantibodies induce a pro-inflammatory, cytotoxic tumor microenvironment. Further, I predict that autoantibodies can drive neoplastic cell phagocytosis in an Fc receptor-dependent manner and recruit additional complement, resulting in immune-stimulatory effects. Excessive complement activation and antibody-dependent cytotoxicity may stimulate anti-tumor responses, including damage to tumor vasculature. Here I provide insights that may aid the development of more effective therapeutic modalities to control cancer. Such therapeutic approaches should kill neoplastic cells and target their interaction with host immune cells. Thereby the pro-tumorigenic effect of dead cancer cells could be limited while inducing the anti-tumor potential of tumor-associated phagocytes.

Deciphering the Intricate Roles of Radiation Therapy and Complement Activation in Cancer

The complement system consists of a collection of serum proteins that act as the main frontline effector arm of the innate immune system. Activation of complement can occur through 3 individual induction pathways: the classical, mannose-binding lectin, and alternative pathways. Activation results in opsonization, recruitment of effector cells through potent immune mediators known as anaphylatoxins, and cell lysis via the formation of the membrane attack complex. Stringent regulation of complement is required to protect against inappropriate activation of the complement cascade. Complement activation within the tumor microenvironment does not increase antitumoral action; instead, it enhances tumor growth and disease progression. Radiation therapy (RT) is a staple in the treatment of malignancies and controls tumor growth through direct DNA damage and the influx of immune cells, reshaping the makeup of the tumor microenvironment. The relationship between RT and complement activity in the tumor microenvironment is uncertain at best. The following review will focus on the complex interaction of complement activation and the immune-modulating effects of RT and the overall effect on tumor progression. The clinical implications of complement activation in cancer and the use of therapeutics and potential biomarkers will also be covered.

Dichotomy of complement system: Tumorigenesis or destruction

Complement system proteins, their regulators and endpoint effector complex significantly promote tumor growth by upregulation of oncogenic growth factors, activation of mitogenic signalling pathways and breakage of normal cell cycle. Contrastingly, complement cascades, initiated by anti-tumor therapeutic antibodies, also play a pivotal role in therapy response. This contradictory role of complement system possibly be a very crucial factor for the outcomes of antibody mediated immunotherapies. Herein, we reviewed the twin role of the complement system in cancer and also the genetic variations in complement system genes. Future studies should be focused on the biomarker discovery for the personalised cancer immunotherapies.

CHD4/NuRD complex regulates complement gene expression and correlates with CD8 T cell infiltration in human hepatocellular carcinoma

Backgrounds

The NuRD (Nucleosome Remodeling and Deacetylation) complex is a repressive complex in gene transcription by modulating chromatin accessibility of target genes to transcription factors and RNA polymerase II. Although individual subunits of the complex have been implicated in many other cancer types, the complex’s role in human hepatocellular carcinoma (HCC) is not fully understood. More importantly, the NuRD complex has not yet been investigated as a whole in cancers.

Methods

We analyzed the expression of the NuRD complex in HCC and evaluated the prognostic value of NuRD complex expression in HCC using the RNA-seq data obtained from the TCGA project. We examined the effect of CHD4 knockdown on HCC cell proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition, colony-forming ability, and on complement gene expression. We also performed bioinformatic analyses to investigate the correlation between the NuRD complex expression and immune infiltration.

Results

We found that nine subunits, out of 14 subunits of the NuRD complex examined, were significantly overexpressed in HCC, and their expression levels were positively correlated with cancer progression. More importantly, our data also demonstrated that these subunits tended to be overexpressed as a whole in HCC. Subsequent studies demonstrated that knockdown of CHD4 in HCC cells inhibits cell proliferation, migration, invasion, and colony-forming ability and promotes apoptosis of HCC cells, indicating that the CHD4/NuRD complex plays oncogenic roles in HCC. Further analysis revealed that the CHD4/NuRD complex regulates complement gene expression in HCC. Intriguingly, we found that the CHD4/NuRD complex expression was inversely correlated with CD8 T cell infiltration in HCC.

Conclusions

Our data demonstrate that the CHD4/NuRD complex plays an oncogenic role in human HCC and regulates complement gene expression in HCC cells. The results of inverse correlation between the CHD4/NuRD complex and CD8 T cell and DC cell infiltration in HCC suggest that the CHD4/NuRD complex not only plays direct regulatory roles in HCC cells, but also has an impact on the immune microenvironment of HCC.

Deciphering tissue-based proteome signatures revealed novel subtyping and prognostic markers for thymic epithelial tumors

Thymic epithelial tumors (TETs) belong to a group of tumors that rarely occur, but have unresolved mechanisms and heterogeneous clinical behaviors. Current care of TET patients demands biomarkers of high sensitivity and specificity for accurate histological classification and prognosis management. In this study, 134 fresh‐frozen tissue samples (84 tumor, 40 tumor adjacent, and 10 normal thymus) were recruited to generate a quantitative and systematic view of proteomic landscape of TETs. Among them, 90 samples were analyzed by data‐independent acquisition mass spectrometry (DIA‐MS) leading to discovery of novel classifying molecules among different TET subtypes. The correlation between clinical outcome and the identified molecules was probed, and the prioritized proteins of interest were further validated on the remaining samples (n = 44) via parallel reaction monitoring (PRM) as well as immunohistochemical and confocal imaging analysis. In particular, two proteins, the cellular mRNA deadenylase CCR4 (carbon catabolite repressor 4)‐NOT (negative on TATA) complex subunit 2/9 (CNOT2/9) and the serine hydroxymethyltransferase that catalyzes the reversible interconversions of serine and glycine (SHMT1), were found at dramatic low levels in the thymic epithelia of more malignant subtype, thymic squamous cell carcinoma (TSCC). Interestingly, the mRNA levels of these two genes were shown to be closely correlated with prognosis of the TET patients. These results extended the existing human tissue proteome atlas and allowed us to identify several new protein classifiers for TET subtyping. Newly identified subtyping and prognosis markers, CNOT2/9 and SHMT1, will expand current diagnostic arsenal in terms of higher specificity and prognostic insights for TET diagnosis and management.

Identification of microenvironment-related genes with prognostic value in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney tumor. Previous studies have shown that the interaction between tumor cells and microenvironment has an important impact on prognosis. Immune and stromal cells are two vital components of the tumor microenvironment. Our study aimed to better understand and explore the genes involved in immune/stromal cells on prognosis. We used the Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data algorithm to calculate immune/stromal scores. According to the scores, we divided ccRCC patients from The Cancer Genome Atlas database into low and high groups and identified the genes which were differentially expressed and significantly associated with prognosis. The result of functional enrichment analysis and protein-protein interaction networks indicated that these genes mainly were involved in extracellular matrix and regulation of cellular activities. Then another independent cohort from the International Cancer Genome Consortium database was used to validate these genes. Finally, we acquired a list of microenvironment-related genes that can predict prognosis for ccRCC patients.

Bispecific antibodies in cancer immunotherapy

Among antibody-based cancer therapies, bispecific antibodies (biAbs) have gained momentum in preclinical and clinical investigations following the regulatory approvals of the trailblazing T-cell engaging biAb (T-biAb) blinatumomab. Discussed herein are recent strategies that aim at boosting the potency and mitigating the toxicity of T-biAbs, broadening their therapeutic utility from hematologic to solid malignancies, and generating T-biAbs in situ. In cancer immunotherapy, T-biAbs are facing fierce competition with chimeric antigen receptor T cells (CAR-Ts), a battle for clinical and commercial viability that will be closely watched. However, innovative combinations of T-biAbs and CAR-Ts have also transpired. NK-cell engaging biAbs (NK-biAbs) are reemerging as an alternative that addresses liabilities of T-biAbs. Beyond NK-biAbs, other biAbs designed to recruit cellular and molecular components of the innate immune system will be covered in this reflection on new tools, technologies, and targets.

Activation of Latent HIV-1 T Cell Reservoirs with a Combination of Innate Immune and Epigenetic Regulators

The presence of T cell reservoirs in which human immunodeficiency virus (HIV) establishes latency by integrating into the host genome represents a major obstacle to an HIV cure and has prompted the development of strategies aimed at the eradication of HIV from latently infected cells. The "shock-and-kill" strategy is one of the most pursued approaches to the elimination of viral reservoirs. Although several latency-reversing agents (LRAs) have shown promising reactivation activity, they have failed to eliminate the cellular reservoir. In this study, we evaluated a novel immune system-mediated approach to clearing the HIV reservoir, based on a combination of innate immune stimulation and epigenetic reprogramming. The combination of the STING agonist cGAMP (cyclic GMP-AMP) and the FDA-approved histone deacetylase inhibitor resminostat resulted in a significant increase in HIV proviral reactivation and specific apoptosis in HIV-infected cells in vitro Reductions in the proportion of HIV-harboring cells and the total amount of HIV DNA were also observed in CD4+ central memory T (TCM) cells, a primary cell model of latency, where resminostat alone or together with cGAMP induced high levels of selective cell death. Finally, high levels of cell-associated HIV RNA were detected ex vivo in peripheral blood mononuclear cells (PBMCs) and CD4+ T cells from individuals on suppressive antiretroviral therapy (ART). Although synergism was not detected in PBMCs with the combination, viral RNA expression was significantly increased in CD4+ T cells. Collectively, these results represent a promising step toward HIV eradication by demonstrating the potential of innate immune activation and epigenetic modulation for reducing the viral reservoir and inducing specific death of HIV-infected cells.IMPORTANCE One of the challenges associated with HIV-1 infection is that despite antiretroviral therapies that reduce HIV-1 loads to undetectable levels, proviral DNA remains dormant in a subpopulation of T lymphocytes. Numerous strategies to clear residual virus by reactivating latent virus and eliminating the reservoir of HIV-1 (so-called "shock-and-kill" strategies) have been proposed. In the present study, we use a combination of small molecules that activate the cGAS-STING antiviral innate immune response (the di-cyclic nucleotide cGAMP) and epigenetic modulators (histone deacetylase inhibitors) that induce reactivation and HIV-infected T cell killing in cell lines, primary T lymphocytes, and patient samples. These studies represent a novel strategy for HIV eradication by reducing the viral reservoir and inducing specific death of HIV-infected cells.

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.

The Role of Membrane Bound Complement Regulatory Proteins in Tumor Development and Cancer Immunotherapy

It has long been understood that the control and surveillance of tumors within the body involves an intricate dance between the adaptive and innate immune systems. At the center of the interplay between the adaptive and innate immune response sits the complement system—an evolutionarily ancient response that aids in the destruction of microorganisms and damaged cells, including cancer cells. Membrane-bound complement regulatory proteins (mCRPs), such as CD46, CD55, and CD59, are expressed throughout the body in order to prevent over-activation of the complement system. These mCRPs act as a double-edged sword however, as they can also over-regulate the complement system to the extent that it is no longer effective at eliminating cancerous cells. Recent studies are now indicating that mCRPs may function as a biomarker of a malignant transformation in numerous cancer types, and further, are being shown to interfere with anti-tumor treatments. This highlights the critical roles that therapeutic blockade of mCRPs can play in cancer treatment. Furthermore, with the complement system having the ability to both directly and indirectly control adaptive T-cell responses, the use of a combinatorial approach of complement-related therapy along with other T-cell activating therapies becomes a logical approach to treatment. This review will highlight the biomarker-related role that mCRP expression may have in the classification of tumor phenotype and predicted response to different anti-cancer treatments in the context of an emerging understanding that complement activation within the Tumor Microenvironment (TME) is actually harmful for tumor control. We will discuss what is known about complement activation and mCRPs relating to cancer and immunotherapy, and will examine the potential for combinatorial approaches of anti-mCRP therapy with other anti-tumor therapies, especially checkpoint inhibitors such as anti PD-1 and PD-L1 monoclonal antibodies (mAbs). Overall, mCRPs play an essential role in the immune response to tumors, and understanding their role in the immune response, particularly in modulating currently used cancer therapeutics may lead to better clinical outcomes in patients with diverse cancer types.

Role of C5b-9 and RGC-32 in Cancer

The complement system represents an effective arsenal of innate immunity as well as an interface between innate and adaptive immunity. Activation of the complement system culminates with the assembly of the C5b-9 terminal complement complex on cell membranes, inducing target cell lysis. Translation of this sequence of events into a malignant setting has traditionally afforded C5b-9 a strict antitumoral role, in synergy with antibody-dependent tumor cytolysis. However, in recent decades, a plethora of evidence has revised this view, highlighting the tumor-promoting properties of C5b-9. Sublytic C5b-9 induces cell cycle progression by activating signal transduction pathways (e.g., Gi protein/ phosphatidylinositol 3-kinase (PI3K)/Akt kinase and Ras/Raf1/ERK1) and modulating the activation of cancer-related transcription factors, while shielding malignant cells from apoptosis. C5b-9 also induces Response Gene to Complement (RGC)-32, a gene that contributes to cell cycle regulation by activating the Akt and CDC2 kinases. RGC-32 is expressed by tumor cells and plays a dual role in cancer, functioning as either a tumor promoter by endorsing malignancy initiation, progression, invasion, metastasis, and angiogenesis, or as a tumor suppressor. In this review, we present recent data describing the versatile, multifaceted roles of C5b-9 and its effector, RGC-32, in cancer.

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.

Complement C5b-9 and Cancer: Mechanisms of Cell Damage, Cancer Counteractions, and Approaches for Intervention

The interactions of cancer cells with components of the complement system are highly complex, leading to an outcome that is either favorable or detrimental to cancer cells. Currently, we perceive only the "tip of the iceberg" of these interactions. In this review, we focus on the complement terminal C5b-9 complex, known also as the complement membrane attack complex (MAC) and discuss the complexity of its interaction with cancer cells, starting with a discussion of its proposed mode of action in mediating cell death, and continuing with a portrayal of the strategies of evasion exhibited by cancer cells, and closing with a proposal of treatment approaches targeted at evasion strategies. Upon intense complement activation and membrane insertion of sufficient C5b-9 complexes, the afflicted cells undergo regulated necrotic cell death with characteristic damage to intracellular organelles, including mitochondria, and perforation of the plasma membrane. Several pro-lytic factors have been proposed, including elevated intracellular calcium ion concentrations and activated JNK, Bid, RIPK1, RIPK3, and MLKL; however, further research is required to fully characterize the effective cell death signals activated by the C5b-9 complexes. Cancer cells over-express a multitude of protective measures which either block complement activation, thus reducing the number of membrane-inserted C5b-9 complexes, or facilitate the elimination of C5b-9 from the cell surface. Concomitantly, cancer cells activate several protective pathways that counteract the death signals. Blockage of complement activation is mediated by the complement membrane regulatory proteins CD46, CD55, and CD59 and by soluble complement regulators, by proteases that cleave complement proteins and by protein kinases, like CK2, which phosphorylate complement proteins. C5b-9 elimination and inhibition of cell death signals are mediated by caveolin and dynamin, by Hsp70 and Hsp90, by the mitochondrial stress protein mortalin, and by the protein kinases PKC and ERK. It is conceivable that various cancers and cancers at different stages of development will utilize distinct patterns of these and other MAC resistance strategies. In order to enhance the impact of antibody-based therapy on cancer, novel precise reagents that block the most effective protective strategies will have to be designed and applied as adjuvants to the therapeutic antibodies.

Obesity, Inflammation, and Prostate Cancer

The prevalence of obesity is increasing in the world, and obesity-induced disease, insulin-resistance, cardiovascular disease, and malignancies are becoming a problem. Epidemiological studies have shown that obesity is associated with advanced prostate cancer and that obese men with prostate cancer have a poorer prognosis. Obesity induces systemic inflammation via several mechanisms. High-fat diet-induced prostate cancer progresses via adipose-secretory cytokines or chemokines. Inflammatory cells play important roles in tumor progression. A high-fat diet or obesity changes the local profile of immune cells, such as myeloid-derived suppressor cells and macrophages, in prostate cancer. Tumor-associated neutrophils, B cells, and complements may promote prostate cancer in the background of obesity. Interventions to control systemic and/or local inflammation and changes in lifestyle may also be viable therapies for prostate cancer.