Immunoglobulin G expression and its colocalization with complement proteins in papillary thyroid cancer

Proteomic and metabolomic features in patients with HCC responding to lenvatinib and anti-PD1 therapy

Combination therapy (lenvatinib/programmed death-1 inhibitor) is effective for treating unresectable hepatocellular carcinoma (uHCC). We reveal that responders have better overall and progression-free survival, as well as high tumor mutation burden and special somatic variants. We analyze the proteome and metabolome of 82 plasma samples from patients with hepatocellular carcinoma (HCC; n = 51) and normal controls (n = 15), revealing that individual differences outweigh treatment differences. Responders exhibit enhanced activity in the alternative/lectin complement pathway and higher levels of lysophosphatidylcholines (LysoPCs), predicting a favorable prognosis. Non-responders are enriched for immunoglobulins, predicting worse outcomes. Compared to normal controls, HCC plasma proteins show acute inflammatory response and platelet activation, while LysoPCs decrease. Combination therapy increases LysoPCs/phosphocholines in responders. Logistic regression/random forest models using metabolomic features achieve good performance in the prediction of responders. Proteomic analysis of cancer tissues unveils molecular features that are associated with side effects in responders receiving combination therapy. In conclusion, our analysis identifies plasma features associated with uHCC responders to combination therapy.

Causal associations between thyroid cancer and IgA nephropathy: a Mendelian randomization study

BACKGROUND

The incidence of kidney disease caused by thyroid cancer is rising worldwide. Observational studies cannot recognize whether thyroid cancer is independently associated with kidney disease. We performed the Mendelian randomization (MR) approach to genetically investigate the causality of thyroid cancer on immunoglobulin A nephropathy (IgAN).

METHODS AND RESULTS

We explored the causal effect of thyroid cancer on IgAN by MR analysis. Fifty-two genetic loci and single nucleotide polymorphisms were related to thyroid cancer. The primary approach in this MR analysis was the inverse variance weighted (IVW) method, and MR‒Egger was the secondary method. Weighted mode and penalized weighted median were used to analyze the sensitivity. In this study, the random-effect IVW models showed the causal impact of genetically predicted thyroid cancer across the IgAN risk (OR, 1.191; 95% CI, 1.131-1.253, P < 0.001). Similar results were also obtained in the weighted mode method (OR, 1.048; 95% CI, 0.980-1.120, P = 0.179) and penalized weighted median (OR, 1.185; 95% CI, 1.110-1.264, P < 0.001). However, the MR‒Egger method revealed that thyroid cancer decreased the risk of IgAN, but this difference was not significant (OR, 0.948; 95% CI, 0.855-1.051, P = 0.316). The leave-one-out sensitivity analysis did not reveal the driving influence of any individual SNP on the association between thyroid cancer and IgAN.

CONCLUSION

The IVW model indicated a significant causality of thyroid cancer with IgAN. However, MR‒Egger had a point estimation in the opposite direction. According to the MR principle, the evidence of this study did not support a stable significant causal association between thyroid cancer and IgAN. The results still need to be confirmed by future studies.

High expression of IGHG1 promotes breast cancer malignant development by activating the AKT pathway

This study researched the exact function of IgG1 heavy chain (IGHG1) on breast cancer (BC) progression. IGHG1 level within BC and paired normal tissues was acquired in Gene Expression Profiling Interactive Analysis dataset. Meanwhile, this work harvested tumor and paired healthy tissues in 42 BC cases. siRNA targeting IGHG1 was transfected into BC cells. SC79 was used to treat the transfected BC cells. CCK-8 assay, clone formation experiment, BrdU assay, Transwell experiment and flow cytometry were carried out to measure the viability, colony formation, proliferation, invasion, and apoptosis of BC cells. Paclitaxel and cisplatin sensitivity of BC cells was evaluated by MTT assay. Real-time quantitative reverse transcription-polymerase chain reaction and Western-blot were performed for measuring mRNA and protein expression. The overexpressed IGHG1 indicated dismal BC survival. IGHG1 silencing attenuated the viability, invasion, proliferation, epithelial-mesenchymal transition, but enhanced the apoptosis of BC cells. IGHG1 silencing enhanced the paclitaxel and cisplatin sensitivity of BC cells. IGHG1 silencing suppressed the activity of the MEK, AKT, and ERK pathways. AKT agonist partially reversed the inhibition of IGHG1 silencing on BC cell malignant phenotype and resistance to paclitaxel and cisplatin. IGHG1 promotes the malignant development of BC by activating the AKT pathway. It may be an effective target for BC treatment.

Radioiodination, purification, and evaluation of antihuman tumor-derived immunoglobulin G light chain monoclonal antibody in tumor-bearing nude mice

We report the synthesis and biological evaluation of ¹³¹ I-labeled antihuman tumor-derived immunoglobulin G (IgG) light chain monoclonal antibody (4E9) ([¹³¹ I]I-4E9) as a promising probe for tumor imaging. [¹³¹ I]I-4E9 was synthesized in radiochemical yield of 89.9 ± 4.7% with radiochemical purity of more than 99%. [¹³¹ I]I-4E9 showed high stability in normal saline and human serum. In cell uptake studies, [¹³¹ I]I-4E9 exhibited favorable binding affinity and high specificity in HeLa MR cells. In biodistribution studies, [¹³¹ I]I-4E9 showed high tumor uptake, high tumor/non-tumor ratios, and specific binding in BALB/c nu/nu mice bearing human HeLa MR xenografts. Single-photon emission computerized tomography (SPECT) imaging of [¹³¹ I]I-4E9 in the HeLa MR xenograft model demonstrated clear visualization of tumor after 48 h and confirmed specific binding in tumor. These findings suggest that [¹³¹ I]I-4E9 possesses favorable biological characteristics and warrants further investigation as a prospective probe for imaging and treatment of cancers.

Kappa/Lambda light-chain typing in Alzheimer's Disease

BACKGROUND

Alzheimer's disease is a progressive neurodegenerative disorder characterized by memory loss and cognitive impairment. The diagnosis of Alzheimer's disease according to symptomatic events is still a puzzling task. Developing a biomarker-based, low-cost, and high-throughput test, readily applicable in clinical laboratories, dramatically impacts the rapid and reliable detection of the disease.

OBJECTIVE

This study aimed to develop an accurate, sensitive, and reliable screening tool for diagnosing Alzheimer's disease, which can significantly reduce the cost and time of existing methods.

METHODS

We have employed a MALDI-TOF-MS-based methodology combined with a microaffinity chromatogra Results: We observed a statistically significant difference in the kappa light chain over lambda light chain (κLC/LC) ratios between patients with AD and controls (% 95 CI: -0.547 to -0.269, p<0.001). Our method demonstrated higher sensitivity (100.00%) and specificity (71.43%) for discrimination between AD and controls.

CONCLUSION

We have developed a high-throughput screening test with a novel sample enrichment method for determining κLC/LC ratios associated with AD diagnosis. Following further validation, we believe our test has a potential for clinical laboratories.

Cancer-Cell-Derived IgG and Its Potential Role in Tumor Development

Human immunoglobulin G (IgG) is the primary component of the human serum antibody fraction, representing about 75% of the immunoglobulins and 10-20% of the total circulating plasma proteins. Generally, IgG sequences are highly conserved, yet the four subclasses, IgG1, IgG2, IgG3, and IgG4, differ in their physiological effector functions by binding to different IgG-Fc receptors (FcγR). Thus, despite a similarity of about 90% on the amino acid level, each subclass possesses a unique manner of antigen binding and immune complex formation. Triggering FcγR-expressing cells results in a wide range of responses, including phagocytosis, antibody-dependent cell-mediated cytotoxicity, and complement activation. Textbook knowledge implies that only B lymphocytes are capable of producing antibodies, which recognize specific antigenic structures derived from pathogens and infected endogenous or tumorigenic cells. Here, we review recent discoveries, including our own observations, about misplaced IgG expression in tumor cells. Various studies described the presence of IgG in tumor cells using immunohistology and established correlations between high antibody levels and promotion of cancer cell proliferation, invasion, and poor clinical prognosis for the respective tumor patients. Furthermore, blocking tumor-cell-derived IgG inhibited tumor cells. Tumor-cell-derived IgG might impede antigen-dependent cellular cytotoxicity by binding antigens while, at the same time, lacking the capacity for complement activation. These findings recommend tumor-cell-derived IgG as a potential therapeutic target. The observed uniqueness of Ig heavy chains expressed by tumor cells, using PCR with V(D)J rearrangement specific primers, suggests that this specific part of IgG may additionally play a role as a potential tumor marker and, thus, also qualify for the neoantigen category.

Current insights into the expression and functions of tumor-derived immunoglobulins

Numerous studies have reported expressions of immunoglobulins (Igs) in many human tumor tissues and cells. Tumor-derived Igs have displayed multiple significant functions which are different from classical Igs produced by B lymphocytes and plasma cells. This review will concentrate on major progress in expressions, functions, and mechanisms of tumor-derived Igs, similarities and differences between tumor-derived Igs and B-cell-derived Igs. We also discuss the future research directions of tumor-derived Igs, including their structural characteristics, physicochemical properties, mechanisms for rearrangement and expression regulation, signaling pathways involved, and clinical applications.

IGHG1 induces EMT in gastric cancer cells by regulating TGF-β/SMAD3 signaling pathway

Objective: Gastric cancer is one of the most common malignant tumors in the world. IGHG1 is a differentially expressed protein screened out in gastric cancer in the early stage of the subject group. This topic explores the expression of IGHG1 in gastric cancer and the effect of IGHG1 on the proliferation, migration, invasion and EMT of gastric cancer SGC7901 cells and its mechanism of action.

Methods: Twenty cases of gastric cancer were purified by laser Capture Microdissection. The isotopic tags for relative and absolute quantification was used to label the proteins, and then analyzed and identified them by quantitative proteomics. Immunohistochemical staining method was used to detect the expression of IGHG1 protein in gastric cancer tissues. Western blot was used to detect the expression of IGHG1 in gastric cancer cells. The MTT and Petri dish clone formation experiment analyzed the effect of low expression of IGHG1 on the proliferation of SGC7901 cells. Scratch test and Transwell migration and invasion test to observe the effect of low expression of IGHG1 on the migration and invasion of SGC7901 cells. Western blot was used to detect the effect of low expression of IGHG1 on the expression of EMT-related proteins.

Results: 243 proteins related to gastric mucosal lesions were preliminarily identified. We found that IGHG1 is highly expressed in gastric cancer tissues compared with normal control tissues. IGHG1 promotes the proliferation, migration and invasion of gastric cancer cells. Compared with the control group, the expression of EMT-related proteins Vimentin, N-cadherin, TGF-β, P-SMAD3 was decreased and the expression of E-cadherin was increased after IGHG1 low expression.

Conclusions: IGHG1 induces EMT in SGC7901 cells by regulating the TGF-β/SMAD3 signaling pathway.

Immunoglobulin Expression in Cancer Cells and Its Critical Roles in Tumorigenesis

Traditionally, immunoglobulin (Ig) was believed to be produced by only B-lineage cells. However, increasing evidence has revealed a high level of Ig expression in cancer cells, and this Ig is named cancer-derived Ig. Further studies have shown that cancer-derived Ig shares identical basic structures with B cell-derived Ig but exhibits several distinct characteristics, including restricted variable region sequences and aberrant glycosylation. In contrast to B cell-derived Ig, which functions as an antibody in the humoral immune response, cancer-derived Ig exerts profound protumorigenic effects via multiple mechanisms, including promoting the malignant behaviors of cancer cells, mediating tumor immune escape, inducing inflammation, and activating the aggregation of platelets. Importantly, cancer-derived Ig shows promising potential for application as a diagnostic and therapeutic target in cancer patients. In this review, we summarize progress in the research area of cancer-derived Ig and discuss the perspectives of applying this novel target for the management of cancer patients.

Mitochondria Autoimmunity and MNRR1 in Breast Carcinogenesis: A Review

We review here the evidence for participation of mitochondrial autoimmunity in BC inception and progression and propose a new paradigm that may challenge the prevailing thinking in oncogenesis by suggesting that mitochondrial autoimmunity is a major contributor to breast carcinogenesis and probably to the inception and progression of other solid tumors. It has been shown that MNRR1 mediated mitochondrial-nuclear function promotes BC cell growth and migration and the development of metastasis and constitutes a proof of concept supporting the participation of mitochondrial autoimmunity in breast carcinogenesis. The resemblance of the autoantibody profile in BC detected by IFA with that in the rheumatic autoimmune diseases suggested that studies on the autoantibody response to tumor associated antigens and the characterization of the mtDNA- and nDNA-encoded antigens may provide functional data on breast carcinogenesis. We also review the studies supporting the view that a panel of autoreactive nDNA-encoded mitochondrial antigens in addition to MNRR1 may be involved in breast carcinogenesis. These include GAPDH, PKM2, GSTP1, SPATA5, MFF, ncRNA PINK1-AS/DDOST as probably contributing to BC progression and metastases and the evidence suggesting that DDX21 orchestrates a complex signaling network with participation of JUND and ATF3 driving chronic inflammation and breast tumorigenesis. We suggest that the widespread autoreactivity of mtDNA- and nDNA-encoded mitochondrial proteins found in BC sera may be the reflection of autoimmunity triggered by mitochondrial and non-mitochondrial tumor associated antigens involved in multiple tumorigenic pathways. Furthermore, we suggest that mitochondrial proteins may contribute to mitochondrial dysfunction in BC even if mitochondrial respiration is found to be within normal limits. However, although the studies show that mitochondrial autoimmunity is a major factor in breast cancer inception and progression, it is not the only factor since there is a multiplex autoantibody profile targeting centrosome and stem cell antigens as well as anti-idiotypic antibodies, revealing the complex signaling network involved in breast carcinogenesis. In summary, the studies reviewed here open new, unexpected therapeutic avenues for cancer prevention and treatment of patients with cancer derived from an entirely new perspective of breast carcinogenesis.

C5aR deficiency attenuates the breast cancer development via the p38/p21 axis

Emerging evidence has shown activation of the complement component C5 to C5a in cancer tissues and C5aR expression in breast cancer cells relates to the tumor development and poor prognosis, suggesting the involvement of complement C5a/C5aR pathway in the breast cancer pathogenesis. In this study, we found that as compared to the non-tumoral tissues, both C5aR and MAPK/p38 showed an elevated expression, but p21/p-p21 showed lower expression, in the tumoral tissues of breast cancer patients. Mice deficient in C5aR or mice treated with the C5aR antagonist exhibited attenuation of breast cancer growth and reduction in the p38/p-p38 expression, but increase in p21/p-p21 expression, in the tumor tissues. Pre-treatment of the breast cancer cells with recombinant C5a resulted in reduced p21 expression, and MAPK/p38 inhibitors prevented C5a-induced reduction in p21 expression, suggesting the involvement of the MAPK/p38 signaling pathway in the C5a/C5aR-mediated suppression of p21/p-p21 expression. These results provide evidence that breast cancer development may rely on C5a/C5aR interaction, for which MAPK/p38 pathway participate in down-regulating the p21 expression. Inhibition of C5a/C5aR pathway is expected to be helpful for the treatment of patients with breast cancer.

Genetic relationship between Hashimoto`s thyroiditis and papillary thyroid carcinoma with coexisting Hashimoto`s thyroiditis

Hashimoto's thyroiditis (HT) is present in the background of around 30% of papillary thyroid carcinomas (PTCs). The genetic predisposition effect of this autoimmune condition is not thoroughly understood. We analyzed the microarray expression profiles of 13 HT, eight PTCs with (w/) coexisting HT, six PTCs without (w/o) coexisting HT, six micro PTCs (mPTCs), and three normal thyroid (TN) samples. Based on a false discovery rate (FDR)-adjusted p-value ≤ 0.05 and a fold change (FC) > 2, four comparison groups were defined, which were HT vs. TN; PTC w/ HT vs. TN; PTC w/o HT vs. TN; and mPTC vs. TN. A Venn diagram displayed 15 different intersecting and non-intersecting differentially expressed gene (DEG) sets, of which a set of 71 DEGs, shared between the two comparison groups HT vs. TN ∩ PTC w/ HT vs. TN, harbored the relatively largest number of genes related to immune and inflammatory functions; oxidative stress and reactive oxygen species (ROS); DNA damage and DNA repair; cell cycle; and apoptosis. The majority of the 71 DEGs were upregulated and the most upregulated DEGs included a number of immunoglobulin kappa variable genes, and other immune-related genes, e.g., CD86 molecule (CD86), interleukin 2 receptor gamma (IL2RG), and interferon, alpha-inducible protein 6 (IFI6). Upregulated genes preferentially associated with other gene ontologies (GO) were, e.g., STAT1, MMP9, TOP2A, and BRCA2. Biofunctional analysis revealed pathways related to immunogenic functions. Further data analysis focused on the set of non-intersecting 358 DEGs derived from the comparison group of HT vs. TN, and on the set of 950 DEGs from the intersection of all four comparison groups. In conclusion, this study indicates that, besides immune/inflammation-related genes, also genes associated with oxidative stress, ROS, DNA damage, DNA repair, cell cycle, and apoptosis are comparably more deregulated in a data set shared between HT and PTC w/ HT. These findings are compatible with the conception of a genetic sequence where chronic inflammatory response is accompanied by deregulation of genes and biofunctions associated with oncogenic transformation. The generated data set may serve as a source for identifying candidate genes and biomarkers that are practical for clinical application.

Natural Killer Cells: Tumor Surveillance and Signaling

Natural killer (NK) cells play a pivotal role in cancer immunotherapy due to their innate ability to detect and kill tumorigenic cells. The decision to kill is determined by the expression of a myriad of activating and inhibitory receptors on the NK cell surface. Cell-to-cell engagement results in either self-tolerance or a cytotoxic response, governed by a fine balance between the signaling cascades downstream of the activating and inhibitory receptors. To evade a cytotoxic immune response, tumor cells can modulate the surface expression of receptor ligands and additionally, alter the conditions in the tumor microenvironment (TME), tilting the scales toward a suppressed cytotoxic NK response. To fully harness the killing power of NK cells for clinical benefit, we need to understand what defines the threshold for activation and what is required to break tolerance. This review will focus on the intracellular signaling pathways activated or suppressed in NK cells and the roles signaling intermediates play during an NK cytotoxic response.

Reduced expression of apolipoprotein E and immunoglobulin heavy constant gamma 1 proteins in Fuchs endothelial corneal dystrophy

BACKGROUND

Fuchs endothelial corneal dystrophy (FECD) is a progressive and potentially a sight threatening disease, and a common indication for corneal grafting in the elderly. Aberrant thickening of Descemet's membrane, formation of microscopic excrescences (guttae) and gradual loss of corneal endothelial cells are the hallmarks of the disease. The aim of this study was to identify differentially abundant proteins between FECD-affected and unaffected Descemet's membrane.

METHODS

Label-free quantitative proteomics using nanoscale ultra-performance liquid chromatography-mass spectrometry (nUPLC-MS^E ) was employed on affected and unaffected Descemet's membrane extracts, and interesting findings were further investigated using quantitative reverse transcription-polymerase chain reaction and immunohistochemical techniques.

RESULTS

Quantitative proteomics revealed significantly lower abundance of apolipoprotein E (APOE) and immunoglobulin heavy constant gamma 1 protein (IGHG1) in affected Descemet's membrane. The difference in the distribution of APOE between affected and unaffected Descemet's membrane and of IGHG1 detected by immunohistochemistry support their down-regulation in the disease. Comparative gene expression analysis showed significantly lower APOE mRNA levels in FECD-affected than unaffected corneal endothelium. IGHG1 gene is expressed at extremely low levels in the corneal endothelium, precluding relative expression analysis.

CONCLUSIONS

This is the first study to report comparative proteomics of Descemet's membrane tissue, and implicates dysregulation of APOE and IGHG1 proteins in the pathogenesis of Fuchs endothelial corneal dystrophy.

IGHG1 Regulates Prostate Cancer Growth via the MEK/ERK/c-Myc Pathway

Increasing evidence indicates that immunoglobulins are important for the regulation of various cancers including prostate cancer (PCa). However, the underlying mechanisms of IgG regulated PCa development remain to be further explored. Here, we demonstrated that IgG1 heavy chain (IGHG1) was increased in tissues from PCa patients. Inhibition of IGHG1 by antibody blocking or genetic knockdown suppressed cell growth and induced cell cycle arrest and ultimate apoptosis. Expression levels of c-Myc were positively correlated with the levels of IGHG1. Furthermore, MEK/ERK/c-Myc pathway lied downstream of IGHG1 in cultured prostate cancer cells. Inhibition of IGHG1 restrained the tumor growth in nude mice and inactivated MEK/ERK/c-Myc pathway both in vitro and in vivo. These findings suggest that IGHG1 play a crucial role during the development of prostate cancer and inhibition of IGHG1 may be a potential therapy in the treatment of PCa.

Human colorectal cancer cells frequently express IgG and display unique Ig repertoire

BACKGROUND

There is growing evidence proving that many human carcinomas, including colon cancer, can overexpress immunoglobulin (Ig); the non B cancer cell-derived Ig usually displayed unique V(D)J rearrangement pattern that are distinct from B cell-derived Ig. Especially, the cancer-derived Ig plays important roles in cancer initiation, progression, and metastasis. However, it still remains unclear if the colon cancer-derived Ig can display unique V(D)J pattern and sequencing, which can be used as novel target for colon cancer therapy.

AIM

To investigate the Ig repertoire features expressed in human colon cancer cells.

METHODS

Seven cancerous tissue samples of colon adenocarcinoma and corresponding noncancerous tissue samples were sorted by fluorescence-activated cell sorting using epithelial cell adhesion molecule as a marker for epithelial cells. Ig repertoire sequencing was used to analyze the expression profiles of all 5 classes of Ig heavy chains (IgH) and the Ig repertoire in colon cancer cells and corresponding normal epithelial cells.

RESULTS

We found that all 5 IgH classes can be expressed in both colon cancer cells and normal epithelial cells. Surprisingly, unlike the normal colonic epithelial cells that expressed 5 Ig classes, our results suggested that cancer cells most prominently express IgG. Next, we found that the usage of Ig in cancer cells caused the expression of some unique Ig repertoires compared to normal cells. Some V_H segments, such as V_H3-7, have been used in cancer cells, and V_H3-74 was frequently present in normal epithelial cells. Moreover, compared to the normal cell-derived Ig, most cancer cell-derived Ig showed unique V_HDJ_H patterns. Importantly, even if the same V_HDJ_H pattern was seen in cancer cells and normal cells, cancer cell-derived IgH always displayed distinct hypermutation hot points.

CONCLUSION

We found that colon cancer cells could frequently express IgG and unique IgH repertoires, which may be involved in carcinogenesis of colon cancer. The unique IgH repertoire has the potential to be used as a novel target in immune therapy for colon cancer.

Cancer IgG, a potential prognostic marker, promotes colorectal cancer progression

Objective

Currently, no satisfactory targets for colorectal cancer or markers for immunotherapy and diagnosis and prognosis are available. Immunoglobulin G (IgG) is widely expressed in many cancers, and it promotes cancer progression. This study explored the role of cancer-derived IgG (CIgG) in colorectal cancer.

Methods

First, using a monoclonal antibody to CIgG, we examined the expression levels of CIgG in colorectal cancer cell lines by western blot and immunofluorescence analyses and in tissue specimens by immunohistochemistry. Second, the variable region gene was amplified by nested polymerase chain reaction (PCR), and PCR products were sequenced and analyzed. Third, we investigated the effect of CIgG on colorectal cancer cells by cell proliferation, wound healing, migration and invasion assays, and colony formation assay. Fourth, we performed in vivo tumorigenicity experiments to explore the effect of CIgG on tumorigenicity. Finally, we used RNA-seq analysis and co-immunoprecipitation experiments to further clarify possible mechanisms of CIgG.

Results

We found that CIgG is widely expressed in colorectal cancer cells, and the overexpression of CIgG indicates significantly poor colorectal cancer prognosis. Furthermore, CIgG knockdown significantly inhibits the proliferation, migration and invasion ability of cells, and tumor growth in vivo. RNA-seq analysis indicated that CIgG knockdown results primarily in changes in expression of apical junction and epithelial-mesenchymal transition-related genes. CIgG may be involved in colorectal cancer invasion and metastasis through interacting with E-cadherin.

Conclusions

CIgG is a potential human oncogene in colorectal cancer and that it has potential for application as a novel target in targeted therapy and a marker for prognostic evaluation.

Low expression of long non-coding RNA GAS5 is associated with poor prognosis of patients with thyroid cancer

The study aims to investigate the role of long non-coding RNA (lncRNA) GAS5 in the diagnosis and prognosis of patients suffering from thyroid cancer (TC). A total of 212 patients with TC and 61 patients with benign thyroid tumor were enrolled in the study. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the lncRNA GAS5 expression in TC and benign tumor tissues. All TC patients were categorized into high-risk and low-risk groups according to the MACIS, AGES and AMES prognostic scoring system. A 5-year follow-up was conducted in order to determine the disease free survival (DFS) rates and overall survival (OS) rates. The associations between lncRNA GAS5 expression and prognosis of TC patients were analyzed by The Kaplan-Meier survival curves and the Cox regression models. There was a decrease in the lncRNA GAS5 expression in TC tissues in comparison to benign tumor tissues. Expression of lncRNA GAS5 showed significant association with tumor node metastasis (TNM) staging, lymph node metastasis and the multiple cancer foci of TC. AMES high-risk patients showed a decreased expression of lncRNA GAS5 expression than the AMES low-risk patients. The AGES and MACIS high-risk patients showed lower lncRNA GAS5 expression than low-risk patients. The survival rate of TC patients with high lncRNA GAS5 expression was higher than that of TC patients with low lncRNA GAS5 expression during the DFS and OS periods. Cox regression analysis indicated that lncRNA GAS5 expression, TNM staging, lymph node metastasis and multiple cancer foci were independent risk factors for poor prognosis in TC patients. LncRNA GAS5 may be closely related to the diagnosis and prognosis of TC.

IgG silencing induces apoptosis and suppresses proliferation, migration and invasion in LNCaP prostate cancer cells

Immunoglobulin G (IgG) has been implicated in the progression of various cancers. This study explored the role of IgG in the proliferation, apoptosis, cell cycle and in vitro invasive properties of LNCaP prostate cancer cells. We used IGHG1 small interfering RNA to silence IgG1 expression in LNCaP cells. The efficacy of IgG1 gene knockdown was confirmed using qPCR and western blotting. The colony formation, proliferation, migration and invasion abilities of LNCaP cells after transfection were assessed using colony-forming, flow cytometry and transwell assays. The expressions of PCNA and caspase-3 proteins in LNCaP cells after transfection were detected with immunofluorescence staining and western blotting. IgG1 silencing significantly decreased the colony formation, survival, cell cycle progression, migration and invasion of LNCaP cells (p < 0.05). IgG1 silencing also reduced the amount of the proliferation marker PCNA and induced formation of the apoptotic marker caspase-3 (p < 0.05). Our results show that IgG1 produced by LNCaP cells confers advantages for tumor cell survival, proliferation, migration and invasion, suggesting that IgG1 is a potential target for prostate cancer treatment.

C5b-9 Staining Correlates With Clinical and Tumor Stage in Gastric Adenocarcinoma

The complement system is a critical part of the immune response, acting in defense against viral infections, clearance of immune complexes, and maintenance of tissue homeostasis. Upregulated expression of the terminal complement complex, C5b-9, has been observed on various tumor cells, such as stomach carcinoma cells, and on cells in the necrotic regions of these tumors as well; however, whether and how C5b-9 is related to gastric cancer progression and severity remains unknown. In this study, human gastric adenocarcinoma (HGAC) tissues (n=47 cases) and patient-matched adjacent nontumoral parenchyma (n=20 cases) were evaluated by tissue microarray and immunohistochemistry. The HGAC tissues showed upregulated C5b-9 expression. Multinomial logistic regression and likelihood ratio testing showed that overexpression of C5b-9 in HGAC tissue was significantly correlated with clinical stage (P=0.007) and tumor stage (P=0.005), but not with tumor distant organ metastasis, lymphoid nodal status, sex, or age. Patients with late-stage gastric adenocarcinoma had a higher amount of tumor cells showing positive staining for C5b-9 than patients with early-stage disease. These results may help in diagnosis and assessment of disease severity of human gastric carcinoma.

Identification of Liver Epithelial Cell-derived Ig Expression in μ chain-deficient mice

Growing evidence indicates that B cells are not the only source of immunoglobulin (Ig). To investigate this discovery further, we used μMT mice, which have a disruption of the first transmembrane exon of the μ heavy chain and do not express the membrane form of IgM. These mice lack mature B cells and thus serve as a good model to explore Ig expression by liver epithelial cells. We found that Ig heavy chains (μ, δ, γ and α) and light chains (κ and λ) were expressed in sorted liver epithelial cells of μMT mice. Surprisingly, each heavy chain class showed its respective variable region sequence characteristics in their variable region, instead of sharing the same VDJ usage, which suggests that class switching does not occur in liver epithelial cells. Moreover, the γ and α chains, but not the μ and δ chains, showed mutations in the variable region, thus indicating that different classes of Ig have different activities. Our findings support the concept that non-B cells, liver epithelial cells here, can produce different classes of Ig.

Immunoglobulin G Expression in Human Sperm and Possible Functional Significance

Immunoglobulin G (IgG), the major molecule of the immune system, which was traditionally thought to be produced by differentiated B-lymphocytes, had recently been found in non-immune cells including spermatozoa of rabbit testis. To study if human sperms could produce IgG that might play a role in fertilization, we employed immunofluorescent staining, Western blot, in situ hybridization, RT-PCR (reverse transcription polymerase chain reaction) and immunoelectron microscope and found that human sperms were capable of synthesizing IgG. IgG protein and mRNA were detected in the cytoplasm, mainly the neck region of the sperm and IgG immunoreactivity was found to cover the entire sperm cell. The essential enzymes necessary for IgG synthesis and class switching, RAG1 (recombination activating gene 1), RAG2 (recombination activating gene 2) and AID (activation-induced cytidine deaminase), were also detected in the sperm cells. Furthermore, we found that anti-IgG antibody could inhibit sperm from penetrating Zona-free hamster egg with statistical significance. These discoveries suggested that immunoglobulin G could be produced by human sperms and it might play a role during fertilization.

Identification of Genes Associated with Smad3-dependent Renal Injury by RNA-seq-based Transcriptome Analysis

Transforming growth factor-β/Smad3 signaling plays a critical role in the process of chronic kidney disease (CKD), but targeting Smad3 systematically may cause autoimmune disease by impairing immunity. In this study, we used whole-transcriptome RNA-sequencing to identify the differential gene expression profile, gene ontology, pathways, and alternative splicing related to TGF-β/Smad3 in CKD. To explore common dysregulation of genes associated with Smad3-dependent renal injury, kidney tissues of Smad3 wild-type and knockout mice with immune (anti-glomerular basement membrane glomerulonephritis) and non-immune (obstructive nephropathy)-mediated CKD were used for RNA-sequencing analysis. Totally 1922 differentially expressed genes (DEGs) were commonly found in these CKD models. The up-regulated genes are inflammatory and immune response associated, while decreased genes are material or electron transportation and metabolism related. Only 9 common DEGs were found to be Smad3-dependent in two models, including 6 immunoglobulin genes (Ighg1, Ighg2c, Igkv12-41, Ighv14-3, Ighv5-6 and Ighg2b) and 3 metabolic genes (Ugt2b37, Slc22a19, and Mfsd2a). Our results identify transcriptomes associated with renal injury may represent a common mechanism for the pathogenesis of CKD and reveal novel Smad3 associated transcriptomes in the development of CKD.

IgG expression in trophoblasts derived from placenta and gestational trophoblastic disease and its role in regulating invasion

Immunoglobulin G (IgG) is an important humoral immune factor, which plays a role in innate immunity of the fetus. IgG immunoreactivity was often seen in trophoblasts of placenta. Traditionally, IgG in trophoblasts was believed to be transported from the maternal blood through neonatal Fc receptor (FcRn). Here, we explored the phenomenon of IgG expression and its role in regulating invasion in trophoblasts derived from normal placenta and gestational trophoblastic disease (GTD). IgG expression was detected with an emphasis on mRNA transcripts by using reverse transcription-polymerase chain reaction and hybridization in situ, besides evaluated at the protein level with immunohistochemistry and immunofluorescence. The migration and attachment of normal trophoblast cell line (TEV-1) and choriocarcinoma cell line (JAR) were inhibited with down-regulation of IgG expression. Methotrexate promoted the differentiation of JAR cell line; however, it had little effect on the differentiation of TEV-1 cell line. IgG expression, migration, and attachment of JAR and TEV-1 cell lines were decreased in the presence of methotrexate. Furthermore, statistical analysis showed that the differences in migration and attachment were significant (P < 0.05) for JAR cell line, while no significant difference was found for TEV-1 cell line. Collectively, these results confirmed that with the progression from normal placenta to GTD, the expression of IgG was increased in trophoblasts, which might actively promote the migration and attachment of trophoblasts as an important regulating factor.

Molecular functions and significance of the MTA family in hormone-independent cancer

The members of the metastasis-associated protein (MTA) family play pivotal roles in both physiological and pathophysiological processes, especially in cancer development and metastasis, and their role as master regulators has come to light. Due to the fact that they were first identified as crucial factors in estrogen receptor-mediated breast cancer metastasis, most of the early studies focused on their hormone-dependent functions. However, the accumulating evidence shows that the members of MTA family are deregulated in most, if not all, the cancers studied so far. Therefore, the levels as well as the activities of the MTA family members are widely accepted as potential biomarkers for diagnosis, prognosis, and predictors of overall survival. They function differently in different cancers with specific mechanisms. p53 and HIF-1α appear to be the respectively common upstream and downstream regulator of the MTA family in both development and metastasis of a wide spectrum of cancers. Here, we review the expression and clinical significance of the MTA family, focusing on hormone-independent cancers. To illustrate the molecular mechanisms, we analyze the MTA family-related signaling pathways in different cancers. Finally, targeting the MTA family directly or the pathways involved in the MTA family indirectly could be invaluable strategies in the development of cancer therapeutics.

MicroRNA-mediated networks underlie immune response regulation in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is a common endocrine malignancy with low death rate but increased incidence and recurrence in recent years. MicroRNAs (miRNAs) are small non-coding RNAs with diverse regulatory capacities in eukaryotes and have been frequently implied in human cancer. Despite current progress, however, a panoramic overview concerning miRNA regulatory networks in PTC is still lacking. Here, we analyzed the expression datasets of PTC from The Cancer Genome Atlas (TCGA) Data Portal and demonstrate for the first time that immune responses are significantly enriched and under specific regulation in the direct miRNA--target network among distinctive PTC variants to different extents. Additionally, considering the unconventional properties of miRNAs, we explore the protein-coding competing endogenous RNA (ceRNA) and the modulatory networks in PTC and unexpectedly disclose concerted regulation of immune responses from these networks. Interestingly, miRNAs from these conventional and unconventional networks share general similarities and differences but tend to be disparate as regulatory activities increase, coordinately tuning the immune responses that in part account for PTC tumor biology. Together, our systematic results uncover the intensive regulation of immune responses underlain by miRNA-mediated networks in PTC, opening up new avenues in the management of thyroid cancer.

Endogenous antibodies for tumor detection

The study of cancer immunology has provided diagnostic and therapeutic instruments through serum autoantibody biomarkers and exogenous monoclonal antibodies. While some endogenous antibodies are found within or surrounding transformed tissue, the extent to which this exists has not been entirely characterized. We find that in transgenic and xenograft mouse models of cancer, endogenous gamma immunoglobulin (IgG) is present at higher concentration in malignantly transformed organs compared to non-transformed organs in the same mouse or organs of cognate wild-type mice. The enrichment of endogenous antibodies within the malignant tissue provides a potential means of identifying and tracking malignant cells in vivo as they mutate and diversify. Exploiting these antibodies for diagnostic and therapeutic purposes is possible through the use of agents that bind endogenous antibodies.

Immunoglobulin G expression in lung cancer and its effects on metastasis

Lung cancer is one of the leading malignancies worldwide, but the regulatory mechanism of its growth and metastasis is still poorly understood. We investigated the possible expression of immunoglobulin G (IgG) genes in squamous cell carcinomas and adenocarcinomas of the lung and related cancer cell lines. Abundant mRNA of IgG and essential enzymes for IgG synthesis, recombination activation genes 1, 2 (RAG1, 2) and activation-induced cytidine deaminase (AID) were detected in the cancer cells but not in adjacent normal lung tissue or normal lung epithelial cell line. The extents of IgG expression in 86 lung cancers were found to associate with clinical stage, pathological grade and lymph node metastasis. We found that knockdown of IgG with siRNA resulted in decreases of cellular proliferation, migration and attachment for cultured lung cancer cells. Metastasis-associated gene 1 (MTA1) appeared to be co-expressed with IgG in lung cancer cells. Statistical analysis showed that the rate of IgG expression was significantly correlated to that of MTA1 and to lymph node metastases. Inhibition of MTA1 gene expression with siRNA also led to decreases of cellular migration and attachment for cultured lung cancer cells. These evidences suggested that inhibition of cancer migration and attachment induced by IgG down-regulation might be achieved through MTA1 regulatory pathway. Our findings suggest that lung cancer-produced IgG is likely to play an important role in cancer growth and metastasis with significant clinical implications.

Cancer-derived immunoglobulin G promotes tumor cell growth and proliferation through inducing production of reactive oxygen species

Cancer cells have been found to express immunoglobulin G (IgG), but the exact functions and underlying mechanisms of cancer-derived IgG remain elusive. In this study, we first confirmed that downregulation of IgG restrained the growth and proliferation of cancer cells in vitro and in vivo. To elucidate its mechanism, we carried out a co-immunoprecipitation assay in HeLa cells and identified 27 potential IgG-interacting proteins. Among them, receptor of activated protein kinase C 1 (RACK1), ras-related nuclear protein (RAN) and peroxiredoxin 1 (PRDX1) are closely related to cell growth and oxidative stress, which prompted us to investigate the mechanism of action of IgG in the above phenomena. Upon confirmation of the interactions between IgG and the three proteins, further experiments revealed that downregulation of cancer-derived IgG lowered levels of intracellular reactive oxygen species (ROS) by enhancing cellular total antioxidant capacity. In addition, a few ROS scavengers, including catalase (CAT), dimethylsulfoxide (DMSO), n-acetylcysteine (NAC) and superoxide dismutase (SOD), further inhibited the growth of IgG-deficient cancer cells through suppressing mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) signaling pathway induced by a low level of intracellular ROS, whereas exogenous hydrogen peroxide (H2O2) at low concentration promoted their survival via increasing intracellular ROS levels. Similar results were obtained in an animal model and human tissues. Taken together, our results demonstrate that cancer-derived IgG can enhance the growth and proliferation of cancer cells via inducing the production of ROS at low level. These findings provide new clues for understanding tumor proliferation and designing cancer therapy.

Role of C5b-9 complement complex and response gene to complement-32 (RGC-32) in cancer

Complement system activation plays an important role in both innate and acquired immunity, with the activation of complement and the subsequent formation of C5b-9 terminal complement complex on cell membranes inducing target cell death. Recognition of this role for C5b-9 leads to the assumption that C5b-9 might play an antitumor role. However, sublytic C5b-9 induces cell cycle progression by activating signal transduction pathways and transcription factors in cancer cells, indicating a role in tumor promotion for this complement complex. The induction of the cell cycle by C5b-9 is dependent upon the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/FOXO1 and ERK1 pathways in a Gi protein-dependent manner. C5b-9 also induces response gene to complement (RGC)-32, a gene that plays a role in cell cycle promotion through activation of Akt and the CDC2 kinase. RGC-32 is expressed by tumor cells and plays a dual role in cancers, in that it has both a tumor suppressor role and tumor-promoting activity. Thus, through the activation of tumor cells, the C5b-9-mediated induction of the cell cycle plays an important role in tumor proliferation and oncogenesis.

Prognostic significance of immunoglobulin M overexpression in laryngeal squamous cell carcinoma

CONCLUSIONS

Immunoglobulin (Ig) M is overexpressed in laryngeal squamous cell carcinoma (LSCC), and its expression has an independent protective impact on disease-free survival in LSCC.

OBJECTIVE

A number of studies have reported on the ectopic expression of Ig in cancer cells, yet there has been a lack of understanding of its clinical and prognostic significance. This study aimed to investigate the expression of IgM in resected specimens of LSCC and to evaluate its clinical significance and prognostic value.

METHODS

Immunohistochemistry (IHC) and Western blotting were used to detect the expression of IgM in LSCC and normal laryngeal tissues. The serum level of IgM was also analyzed by immunoturbidimetric assay.

RESULTS

IHC and Western blot studies demonstrated that IgM was overexpressed in LSCC specimens (p < 0.001), while the serum level of IgM in patients with LSCC was not different from healthy controls. Chi-squared analysis revealed that the expression level of IgM was negatively correlated with regional lymph node metastasis and tumor stage (p = 0.011 and 0.025, respectively). Univariate analysis showed that IgM expression was significantly correlated with enhanced disease-free survival (DFS) (p = 0.004). In multivariate analysis, IgM retained its independent prognostic value for DFS (p = 0.048, HR = 0.506, 95% CI = 0.257-0.995).

Suppression of IGHG1 gene expression by siRNA leads to growth inhibition and apoptosis induction in human prostate cancer cell

To investigate the immunoglobulin G (IgG) expression in prostate cancer cell lines and explore the effects of IGHG1 gene knockdown on PC3 cell growth and apoptosis. Flow cytometry, qPCR and western blot were used to demonstrate IgG expression in prostate cancer cell lines. PC3 cells were transfected with designed siRNA, the expression of IgG was determined by qPCR and western blot, the proliferation and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenil)-2H-tetrazolium, inner salt (MTS) and flow cytometry. The percentages of IgG in LNCaP cell membrane and cytoplasm were 2.96 and 89.22 % by flow cytometer, those of PC3 cell were 86.73 and 90.99 % respectively. The average level of IgG1 mRNA expression in PC3 cell line was significantly higher than that in LNCaP cell line (3.08 ± 0.15 vs 1.00 ± 0.37, P = 0.001). The protein level of IgG expression of PC3 cell line was 1.92 ± 0.15, compared with LNCaP cell line (1.05 ± 0.86). The expression of IgG1 mRNA and protein level in transfected PC3 cells decreased, with significant statistical differences from the blank control group (P < 0.01). The PC3 cell growth inhibition rates were 31.3 and 43.3 % in 48 and 72 h respectively. The rate of apoptotic PC3 cells were 5.29 ± 0.41 % in experimental group higher than that in control group (1.49 ± 0.29 %) (P < 0.01). IgG was identified in prostate cancer cells, and the siRNA targeted silencing of IGHG1 can inhibit cell viability and promote apoptosis, which might therefore act as a potential target in prostate cancer gene therapy.