Immunohistochemistry of Complement Response on Human Renal Cell Carcinoma Biopsies

Epigenetic and transcriptomic characterization reveals progression markers and essential pathways in clear cell renal cell carcinoma

Identifying tumor-cell-specific markers and elucidating their epigenetic regulation and spatial heterogeneity provides mechanistic insights into cancer etiology. Here, we perform snRNA-seq and snATAC-seq in 34 and 28 human clear cell renal cell carcinoma (ccRCC) specimens, respectively, with matched bulk proteogenomics data. By identifying 20 tumor-specific markers through a multi-omics tiered approach, we reveal an association between higher ceruloplasmin (CP) expression and reduced survival. CP knockdown, combined with spatial transcriptomics, suggests a role for CP in regulating hyalinized stroma and tumor-stroma interactions in ccRCC. Intratumoral heterogeneity analysis portrays tumor cell-intrinsic inflammation and epithelial-mesenchymal transition (EMT) as two distinguishing features of tumor subpopulations. Finally, BAP1 mutations are associated with widespread reduction of chromatin accessibility, while PBRM1 mutations generally increase accessibility, with the former affecting five times more accessible peaks than the latter. These integrated analyses reveal the cellular architecture of ccRCC, providing insights into key markers and pathways in ccRCC tumorigenesis.

B cells in the tumor microenvironment: Multi-faceted organizers, regulators, and effectors of anti-tumor immunity

Our understanding of tumor-infiltrating lymphocytes (TILs) is rapidly expanding beyond T cell-centric perspectives to include B cells and plasma cells, collectively referred to as TIL-Bs. In many cancers, TIL-Bs carry strong prognostic significance and are emerging as key predictors of response to immune checkpoint inhibitors. TIL-Bs can perform multiple functions, including antigen presentation and antibody production, which allow them to focus immune responses on cognate antigen to support both T cell responses and innate mechanisms involving complement, macrophages, and natural killer cells. In the stroma of the most immunologically "hot" tumors, TIL-Bs are prominent components of tertiary lymphoid structures, which resemble lymph nodes structurally and functionally. Additionally, TIL-Bs participate in a variety of other lympho-myeloid aggregates and engage in dynamic interactions with the tumor stroma. Here, we summarize our current understanding of TIL-Bs in human cancer, highlighting the compelling therapeutic opportunities offered by their unique tumor recognition and effector mechanisms.

Role of Complement in Regulating Inflammation Processes in Renal and Prostate Cancers

For decades, the complement system, the central pillar of innate immune response, was recognized as a protective mechanism against cancer cells and the manipulation of complement effector functions in cancer setting offered a great opportunity to improve monoclonal antibody-based cancer immunotherapies. Similarly, cellular senescence, the process of cell cycle arrest that allow DNA and tissue repair has been traditionally thought to be able to suppress tumor progression. However, in recent years, extensive research has identified the complement system and cellular senescence as two main inducers of tumour growth in the context of chronic, persistent inflammation named inflammaging. Here, we discuss the data describing the ambivalent role of senescence in cancer with a particular focus on tumors that are strongly dependent on complement activation and can be understood by a new, senescence-related point of view: prostate cancer and renal cell carcinoma.

Deposition of the Membrane Attack Complex in Healthy and Diseased Human Kidneys

The membrane attack complex-also known as C5b-9-is the end-product of the classical, lectin, and alternative complement pathways. It is thought to play an important role in the pathogenesis of various kidney diseases by causing cellular injury and tissue inflammation, resulting in sclerosis and fibrosis. These deleterious effects are, consequently, targeted in the development of novel therapies that inhibit the formation of C5b-9, such as eculizumab. To clarify how C5b-9 contributes to kidney disease and to predict which patients benefit from such therapy, knowledge on deposition of C5b-9 in the kidney is essential. Because immunohistochemical staining of C5b-9 has not been routinely conducted and never been compared across studies, we provide a review of studies on deposition of C5b-9 in healthy and diseased human kidneys. We describe techniques to stain deposits and compare the occurrence of deposits in healthy kidneys and in a wide spectrum of kidney diseases, including hypertensive nephropathy, diabetic nephropathy, membranous nephropathy, IgA nephropathy, lupus nephritis, C3 glomerulopathy, and thrombotic microangiopathies such as the atypical hemolytic uremic syndrome, vasculitis, interstitial nephritis, acute tubular necrosis, kidney tumors, and rejection of kidney transplants. We summarize how these deposits are related with other histological lesions and clinical characteristics. We evaluate the prognostic relevance of these deposits in the light of possible treatment with complement inhibitors.

Paraneoplastic Pemphigus and Autoimmune Blistering Diseases Associated with Neoplasm: Characteristics, Diagnosis, Associated Neoplasms, Proposed Pathogenesis, Treatment

Autoimmune paraneoplastic and neoplasm-associated skin syndromes are characterized by autoimmune-mediated cutaneous lesions in the presence of a neoplasm. The identification of these syndromes provides information about the underlying tumor, systemic symptoms, and debilitating complications. The recognition of these syndromes is particularly helpful in cases of skin lesions presenting as the first sign of the malignancy, and the underlying malignancy can be treated in a timely manner. Autoimmune paraneoplastic and neoplasm-associated bullous skin syndromes are characterized by blister formation due to an autoimmune response to components of the epidermis or basement membrane in the context of a neoplasm. The clinical manifestations, histopathology and immunopathology findings, target antigens, associated neoplasm, current diagnostic criteria, current understanding of pathogenesis, and treatment options for a selection of four diseases are reviewed. Paraneoplastic pemphigus manifests with clinically distinct painful mucosal erosions and polymorphic cutaneous lesions, and is often associated with lymphoproliferative neoplasm. In contrast, bullous pemphigoid associated with neoplasm presents with large tense subepidermal bullae of the skin, and mild mucosal involvement, but without unique clinical features. Mucous membrane pemphigoid associated with neoplasm is a disorder of chronic subepithelial blisters that evolve into erosions and ulcerations that heal with scarring, and involves stratified squamous mucosal surfaces. Linear IgA dermatosis associated with neoplasm is characterized by annularly grouped pruritic papules, vesicles, and bullae along the extensor surfaces of elbows, knees, and buttocks. Physicians should be aware that these autoimmune paraneoplastic and neoplasm-associated syndromes can manifest distinct or similar clinical features as compared with the non-neoplastic counterparts.

Elevated expression of SLC34A2 inhibits the viability and invasion of A549 cells

Abnormal expression of solute carrier family 34 (sodium phosphate), member 2 (SLC34A2) in the lung may induce abnormal alveolar type II (AT II) cells to transform into lung adenocarcinoma cells, and may also be important in biological process of lung adenocarcinoma. However, at present, the effects and molecular mechanisms of SLC34A2 in the initiation and progression of lung cancer remain to be elucidated. To the best of our knowledge, the present study revealed for the first time that the expression levels of SLC34A2 were downregulated in the A549 and H1299 lung adenocarcinoma cell lines. Further investigation demonstrated that the elevated expression of SLC34A2 in A549 cells was able to significantly inhibit cell viability and invasion in vitro. In addition, 10 upregulated genes between the A549-P-S cell line stably expressing SLC34A2 and the control cell line A549-P were identified by microarray analysis and quantitative polymerase chain reaction, including seven tumor suppressor genes and three complement genes. Furthermore, the upregulation of complement gene C3 and complement 4B preproprotein (C4b) in A549-P-S cells was confirmed by ELISA analysis and was identified to be correlated with recovering Pi absorption in A549 cells by the phosphomolybdic acid method by enhancing the expression of SLC34A2. Therefore, it was hypothesized that the mechanisms underlying the effect of SLC34A2 on A549 cells might be associated with the activation of the complement alternative pathway (C3 and C4b) and upregulation of the expression of selenium binding protein 1, thioredoxin-interacting protein, PDZK1-interacting protein 1 and dual specificity protein phosphatase 6. Downregulation of SLC34A2 may primarily cause abnormal AT II cells to escape from complement-associated immunosurveillance and abnormally express certain tumor-suppressor genes inducing AT II cells to develop into lung adenocarcinoma. The present study further elucidated the effects and mechanisms of SLC34A2 in the generation and development of lung cancer.

Modulation of CD59 expression by restrictive silencer factor-derived peptides in cancer immunotherapy for neuroblastoma

Tumor cells escape clearance by complement by abundantly expressing CD59 and other membrane complement regulators. Existing strategies for blocking/knocking down these regulators can contribute to tumor immunoclearance in vitro; however, there are numerous difficulties restricting their use in vivo. Here, we report a new strategy for suppression of CD59 expression in neuroblastoma using peptides that target regulators of CD59 expression. We identified the neural-restrictive silencer factor (REST) as a target for modulation of CD59 expression in neuroblastoma. We next designed plasmids that encoded peptides comprising different DNA-binding domains of REST and transfected them into neuroblastoma cell lines. These peptides suppressed CD59 expression, sensitizing neuroblastoma to complement-mediated killing triggered by anti-GD2 therapeutic monoclonal antibody. These CD59-modulating peptides might be effective therapeutic adjuvants to therapeutic monoclonal antibodies used for treatment of neuroblastoma and other cancer types sharing the same mechanism for regulation of CD59 expression.

Expression of complement restriction factors (CD46, CD55 & CD59) in head and neck squamous cell carcinomas

BACKGROUND

Tumor cells can escape complement-dependent cytotoxicity (CDC) by expressing complement restriction factors (CRFs), CD46, CD55 and CD59. CRF-expression in non-neoplastic mucosa of the head and neck was compared with biopsies of the head and neck squamous cell carcinoma (HNSCC) and cell lines derived from oral squamous cell carcinomas (OSCC).

METHODS

Normal mucosa and HNSCC tumor tissue (poor, moderate, or well differentiated) specimens were immunostained with anti-CRF monoclonal antibodies. Immunostaining of the OSCC cell lines (SCC12 and SCC71) was examined under laser scan fluorescence microscopy.

RESULTS

CD46, CD55 and CD59 were highly expressed in HNSCC cells including T1/T2N0M0 stages. The CRF expression was much lower or absent in non-neoplastic squamous epithelia or in the submucosa of both normal and tumor tissues.

CONCLUSIONS

Enhanced staining of tumor tissues at stages T1/T2 indicates that the CRFs are overexpressed by primary tumors before metastasis to either lymph nodes or organs (N0M0 stage) suggesting that CRFs are formed early during tumorigenesis.

Decay-accelerating factor (CD55): a versatile acting molecule in human malignancies

The decay-accelerating factor (DAF, CD55) physiologically serves as an inhibitor of the complement system. Moreover, DAF is broadly expressed in malignant tumors. Here, DAF seems to dispose of several different functions reaching far beyond its immunological role, e.g., promotion of tumorigenesis, decrease of complement mediated tumor cell lysis, autocrine loops for cell rescue and evasion of apoptosis, neoangiogenesis, invasiveness, cell motility, and metastasis via oncogenic tyrosine kinase pathway activation, and specific seven-span transmembrane receptors (CD97) binding. Furthermore, DAF has already been included in diagnostic or therapeutic studies. Thereby, studies applying monoclonal anti-DAF antibodies and anti-DAF vaccination for a targeted therapy have been enrolled recently.

p53 Regulates Cellular Resistance to Complement Lysis through Enhanced Expression of CD59

It has been recently hypothesized that the CD59 gene has two putative p53-responsive elements that may be involved in defense of host cells from damage by the complement system in inflammation. Here we have examined the roles of these putative p53-binding sequences within the CD59 gene in regulation of CD59 expression. We have shown that both of these potential responsive elements bind p53 in vitro. Knocking down expression of p53 using small interfering RNA led to a 6-fold decrease in CD59 protein expression in HeLa cells. We have previously observed a decrease of CD59 in camptothecin-induced apoptotic IMR32 cells, whereas expression was increased in the surviving fraction compared with untreated cells. Here, we have shown that these changes are associated with altered expression levels and acetylation status of p53. We have also shown that acetylation status of p53 regulates CD59 expression on cells exposed to inflammatory cytokines to model inflammation. Our data suggest that p53 and in vivo positive/negative regulators of p53 could be used to modulate susceptibility of tumor cells to complement lysis in chemotherapy.

Ascitic complement system in ovarian cancer

Ovarian cancer spreads intraperitoneally and forms fluid, whereby the diagnosis and therapy often become delayed. As the complement (C) system may provide a cytotoxic effector arm for both immunological surveillance and mAb-therapy, we have characterised the C system in the intraperitoneal ascitic fluid (AF) from ovarian cancer patients. Most of the AF samples showed alternative and classical pathway haemolytic activity. The levels of C3 and C4 were similar to or in the lower normal range when compared to values in normal sera, respectively. However, elevated levels of C3a and soluble C5b-9 suggested C activation in vivo. Malignant cells isolated from the AF samples had surface deposits of C1q and C3 activation products, but not of C5b-9 (the membrane attack complex; MAC). Activation could have become initiated by anti-tumour cell antibodies that were detected in the AFs and/or by changes on tumour cell surfaces. The lack of MAC was probably due to the expression of C membrane regulators CD46, CD55 and CD59 on the tumour cells. Soluble forms of C1 inhibitor, CD59 and CD46, and the alternative pathway inhibitors factor H and FHL-1 were present in the AF at concentrations higher than in serum samples. Despite the presence of soluble C inhibitors it was possible to use AF as a C source in antibody-initiated killing of ovarian carcinoma cells. These results demonstrate that although the ovarian ascitic C system fails as an effective immunological surveillance mechanism, it could be utilised as an effector mechanism in therapy with intraperitoneally administrated mAbs, especially if the intrinsic C regulators are neutralised.

The inhibitory effect of CD46, CD55, and CD59 on complement activation after immunotherapeutic treatment of cervical carcinoma cells with monoclonal antibodies or bispecific monoclonal antibodies

The role of membrane-bound complement regulatory proteins (mCRP) in the protection of tumor cells in vivo against elimination by the immune system is still unknown. In this study the effect of expression of these mCRP by cervical cancer cells was investigated. In situ expression of mCRP was observed on cervical carcinomas, normal cervical epithelial cells, and the surrounding stroma. Deposition of C3 and C5b-9 was sporadically found on the tumor cells and the surrounding stroma. A low expression of CD46 was statistically significantly associated with deposition of C3. Comparable expression patterns were shown on primary cervical tumor cell suspensions. A relatively high deposition of C4c was found on these tumor cells, indicating classical pathway activation. Furthermore, it was demonstrated that CD55 and CD59 were the most potent inhibitors of C3 deposition and classical pathway-mediated lysis, respectively, on cervical cancer cell lines. The feasibility of increasing complement activation at the tumor cell membrane surface was demonstrated with an anti-HLA Class I*anti-CD55 bispecific mAb. The potential immunotherapeutic applicability was investigated with both anti-G250*anti-CD55 and anti-Ep-CAM*anti-CD55 bispecific mAbs. An approximate 2-fold increase in C3 deposition, compared with the parental anti-Ep-CAM mAb, was attained with an anti-Ep-CAM*anti-CD55 bispecific mAb when the tumor-associated antigen was expressed in sufficient amounts. These results demonstrate that when tumor-associated antigens are expressed in adequate amounts, bispecific mAbs in vivo may be potent immunotherapeutic agents to enhance an inflammatory reaction at the tumor site.

Linear IgA bullous dermatosis in a patient with renal cell carcinoma

Linear IgA bullous dermatosis (LABD) is an autoimmune subepidermal bullous disease with heterogeneous clinical manifestations, characterized by linear deposition of IgA along the epidermal basement membrane zone. We report a patient with a metastasized renal cell carcinoma who developed an extensive blistering eruption. The lesions showed immunopathological findings characteristic of LABD. The patient showed a fair response to prednisolone and dapsone. Treatment to control the LABD was no longer required when interferon-alfa was started as palliative therapy for the metastasized renal cell carcinoma. The association of LABD and malignancies has been documented before and is not due to mere chance alone.

Specific von Hippel-Lindau protein expression of clear cell renal cell carcinoma with "immunogenic" features

Human clear cell renal cell carcinoma (CCRCC) is characterized by specific von Hippel-Lindau (VHL) gene alterations and immunogenic features. In the present study, the immunohistochemical expression of the von Hippel-Lindau gene protein (pVHL) was compared with the presence of major histocompatibility complex (MHC I-II), tumor infiltrating lymphocytes (TIL) and tumoral immune complexes (TIC) in CCRCC. Native tumor tissues of 132 RCC patients (95 with the common clear cell subtype), diagnosed according to the Heidelberg classification, were obtained for immunohistochemistry. Tumor stainings with pVHL, MHC I-II and tumor infiltrating lymphocytes (T and B lymphocytes, monocytes) were detected by immunoperoxidase methods using monoclonal antibodies. Tumoral immune complexes (IgG, IgA, IgM and C1q, C3 complement proteins) were visualized by fluorescent polyclonal antibodies. Immune stainings were semiquantitatively evaluated. Specificity and sensitivity of these markers in relation to the common histological subtype of RCC (CCRCC) were calculated. CCRCC was characterized by specific pVHL expression. At the same time, CCRCC was associated with constitutional MHC I-II expression and highly specific degree of TIL and TIC. It is concluded that specific pVHL expression of CCRCC is frequently associated with immunogenic features. Immunohistochemical analysis aims the initial tumor staging of RCC patients to achieve better patient selection for immunotherapy. However, the association of pVHL expression with the immunogenic CCRCC is statistically relevant, the mechanism and its clinical relevance in immunotherapy still remains to be tested.

Prognostic histological and immune markers of renal cell carcinoma

Recent development on the fields of molecular genetics and immunology of human renal cell carcinoma (RCC) have resulted in more successful treatment of advanced and metastatic RCCs. Re-evaluation of the prognostic/predictive data aim the initial tumor staging of RCC patients to achieve better patient selection for immune and gene therapy. 125 RCC patients diagnosed according to the Heidelberg histological classification, graded, Robson staged, immune treated (Interferon-a a+ Vinblastine or Broncho-Waxom/Decaris) were followed-up clinically for 36 months. Tumor immunity markers by immunohistochemistry of tumor infiltrating lymphocytes (TIL) were detected by immunoperoxidase methods using monoclonal antibodies. Tumoral immune complexes (TIC) were visualized by fluorescent polyclonal antibodies. Histologically oncocytomas defined a better (p<0.02) and sarcomatous RCCs a worse (p<0.01) follow-up prognosis. Basically, the metastatic status (related with the stage and grade) determined the clinical outcome (p<0.00002) of the RCC patients. Tumoral immune complexes (TIC) were weak positive, while tumor infiltrating lymphocytes (TIL) weak negative predictors of the succes of Broncho-Waxom/Decaris immune therapy. Molecular genetic based histological classification, grade, stage and metastatic status parameters together with some tumor immunity parameters (TIL, TIC) can predict the success of immunotherapy of RCC patients.

Mannan-binding lectin (MBL)-associated plasma protein present in human urine inhibits calcium oxalate crystal growth

Mannan-binding lectin (MBL)-associated plasma protein (MAp19) is an alternatively spliced form of MBL-associated serine protease-2, a component of a complement activation cascade. We observed that MAp19 is excreted in human urine. Interestingly, the amount of MAp19 was higher in urine of renal cell carcinoma patients than healthy people. Pretreatment of urine dialysate with 50 mM EDTA increased the recovery of MAp19, suggesting that MAp19 is a calcium-binding protein. The recombinant MAp19 showed a strong inhibition of calcium oxalate crystal growth in vitro in a concentration-dependent manner. Thus, we conclude that MAp19 plays a role in the inhibition of calcium oxalate renal stone formation.