Cancer-driven IgG promotes the development of prostate cancer though the SOX2-CIgG pathway

Loss of heterozygosity impacts MHC expression on the immune microenvironment in CDK12-mutated prostate cancer

BACKGROUND

In prostate cancer (PCa), well-established biomarkers such as MSI status, TMB high, and PDL1 expression serve as reliable indicators for favorable responses to immunotherapy. Recent studies have suggested a potential association between CDK12 mutations and immunotherapy response; however, the precise mechanisms through which CDK12 mutation may influence immune response remain unclear. A plausible explanation for immune evasion in this subset of CDK12-mutated PCa may be reduced MHC expression.

RESULTS

Using genomic data of CDK12-mutated PCa from 48 primary and 10 metastatic public domain samples and a retrospective cohort of 53 low-intermediate risk primary PCa, we investigated how variation in the expression of the MHC genes affected associated downstream pathways. We classified the patients based on gene expression quartiles of MHC-related genes and categorized the tumors into "High" and "Low" expression levels. CDK12-mutated tumors with higher MHC-expressed pathways were associated with the immune system and elevated PD-L1, IDO1, and TIM3 expression. Consistent with an inflamed tumor microenvironment (TME) phenotype, digital cytometric analyses identified increased CD8 + T cells, B cells, γδ T cells, and M1 Macrophages in this group. In contrast, CDK12-mutated tumors with lower MHC expression exhibited features consistent with an immune cold TME phenotype and immunoediting. Significantly, low MHC expression was also associated with chromosome 6 loss of heterozygosity (LOH) affecting the entire HLA gene cluster. These LOH events were observed in both major clonal and minor subclonal populations of tumor cells. In our retrospective study of 53 primary PCa cases from this Institute, we found a 4% (2/53) prevalence of CDK12 mutations, with the confirmation of this defect in one tumor through Sanger sequencing. In keeping with our analysis of public domain data this tumor exhibited low MHC expression at the RNA level. More extensive studies will be required to determine whether reduced HLA expression is generally associated with primary tumors or is a specific feature of CDK12 mutated PCa.

CONCLUSIONS

These data show that analysis of CDK12 alteration, in the context of MHC expression levels, and LOH status may offer improved predictive value for outcomes in this potentially actionable genomic subgroup of PCa. In addition, these findings highlight the need to explore novel therapeutic strategies to enhance MHC expression in CDK12-defective PCa to improve immunotherapy responses.

SOX2-associated signaling pathways regulate biological phenotypes of cancers

SOX2 is a transcription factor involved in multiple stages of embryonic development. In related reports, SOX2 was found to be abnormally expressed in tumor tissues and correlated with clinical features such as TNM staging, tumor grade, and prognosis in patients with various cancer types. In most cancer types, SOX2 is a tumor-promoting factor that regulates tumor progression and metastasis primarily by maintaining the stemness of cancer cells. In addition, SOX2 also regulates the proliferation, apoptosis, invasion, migration, ferroptosis and drug resistance of cancer cells. However, SOX2 acts as a tumor suppressor in some cases in certain cancer types, such as gastric and lung cancer. These key regulatory functions of SOX2 involve complex regulatory networks, including protein-protein and protein-nucleic acid interactions through signaling pathways and noncoding RNA interactions, modulating SOX2 expression may be a potential therapeutic strategy for clinical cancer patients. Therefore, we sorted out the phenotypes related to SOX2 in cancer, hoping to provide a basis for further clinical translation.

SIA-IgG confers poor prognosis and represents a novel therapeutic target in breast cancer

The incidence rate of breast cancer is the highest in the world, and major problem in the clinical treatment is the therapy resistance of breast cancer stem cells (CSCs). Thus, new therapeutic approaches targeting breast CSCs are needed. Our previous study demonstrated cancer-derived sialylated IgG (SIA-IgG) is highly expressed in cancer cells with stem/progenitor features. Furthermore, a high frequency of SIA-IgG in breast cancer tissue predicted metastasis and correlated with poor prognosis factors, and depletion of IgG in breast cancer leads to lower malignancy of cancer cells, suggesting SIA-IgG could be a potential therapeutic target in breast cancer. In this study, we first investigated the relationship of SIA-IgG expression with the clinicopathological characteristics and clinical prognosis of breast carcinoma patients, and the data confirmed that the expression of SIA-IgG confers poor prognosis in breast cancer. Successively, by using a monoclonal antibody specifically against SIA-IgG, we targeted SIA-IgG on the surface of MDA-MB-231 cells and detected their functional changes, and the results suggested SIA-IgG to be a promising antibody therapeutic target in breast cancer. In addition, we explored the mechanism of action at the molecular level of SIA-IgG on breast cancer cell, the findings suggest that SIA-IgG promotes proliferation, metastasis, and invasion of breast cancer cells through the Wnt/β-catenin signaling pathway. Developing therapeutic antibody needs effective therapeutic target, and the antibody should better be a monoclonal antibody with high affinity and high specificity. This study provides a potential prognostic marker and a novel therapeutic target for breast cancer.

Upregulated Expression of Cancer-Derived Immunoglobulin G Is Associated With Progression in Glioma

Objective

Gliomas are the most aggressive intracranial tumors accounting for the vast majority of brain tumors with very poor prognosis and overall survival (OS). Cancer-derived immunoglobulin G (cancer-IgG) has been found to be widely expressed in several malignancies such as breast cancer, colorectal cancer, and lung cancer. Cancer-IgG could promote tumorigenesis and progression. However, its role in glioma has not been revealed yet.

Methods

We mined open databases including the Chinese Glioma Genome Atlas (CGGA), The Cancer Genome Atlas (TCGA), and the Gene Expression Omnibus (GEO) to study the role of IGHG1, which encodes cancer-IgG in glioma. Examination of the differential expression of IGHG1 was carried out in the GEO and TCGA databases. Furthermore, its expression in different molecular subtypes was analyzed. Stratified analysis was performed with clinical features. Subsequently, immune infiltration analysis was conducted using single-sample gene set enrichment analysis (ssGSEA). GSEA was performed to reveal the mechanisms of IGHG1. Lastly, immunohistochemistry was processed to validate our findings.

Results

In this study, we found that the expression of IGHG1 was higher in glioma and molecular subtypes with poor prognosis. The overall survival of patients with a high expression of IGHG1 was worse in the stratified analysis. Immune infiltration analysis indicated that the expression level of IGHG1 was positively correlated with the stromal score, ESTIMATE score, and immune score and negatively correlated with tumor purity. Results from the GSEA and DAVID demonstrated that IGHG1 may function in phagosome, antigen processing and presentation, extracellular matrix structural constituent, antigen binding, and collagen-containing extracellular matrix. Finally, immunohistochemistry assay validated our findings that patients with a high expression of cancer-IgG had poor OS and disease-free survival (DFS).

Conclusion

Cancer-IgG is a promising biomarker of diagnosis and treatment for patients with glioma.

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.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

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.

High Expression of Cancer-IgG Is Associated With Poor Prognosis and Radioresistance via PI3K/AKT/DNA-PKcs Pathway Regulation in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the dominant type of lung neoplasms, and radiotherapy is its mainstay treatment, yet poor prognosis caused by radioresistance remains problematic. Cancer-derived immunoglobulin G (cancer-IgG) has been detected in multiple cancers and plays important roles in carcinogenesis. This study aimed to demonstrate that cancer-IgG is associated with poor prognosis of LUAD and to identify its role in radioresistance.

Methods

Cancer-IgG expression was detected by immunohistochemistry from 56 patients with stage III LUAD and by western blot and immunofluorescence in LUAD cell lines and in a human bronchial epithelial cell line. The effects of cancer-IgG silencing on the proliferation and apoptosis of PC9 and H292 cells were evaluated by plate cloning and apoptosis assay; the effects of cancer-IgG silencing on DNA damage repair ability and radiosensitivity were evaluated by colony-forming assay, γH2AX immunofluorescence, and neutral comet assay. Finally, we used the protein phosphorylation microarray and western blot to explore mechanisms involving cancer-IgG that increased radioresistance.

Results

Cancer-IgG is widely expressed in stage III LUAD, and the overall survival and disease-free survival of patients with positive expression are notably lower than those of patients with negative expression, indicating the associations between cancer-IgG and poor prognosis as well as radioresistance. The expression of cancer-IgG in the four LUAD cell lines was located mainly on the cell membrane and cytoplasm and not in the normal lung epithelial cell. Knockdown of cancer-IgG in PC9 and H292 cells resulted in increased apoptosis and negatively affected cancer cell proliferation. After irradiation, silencing of cancer-IgG showed a decrease in colonies as well as increases in the Olive tail moment and γH2AX foci in nucleus, indicating that the knockdown of cancer-IgG resulted in a decrease in the damage repair ability of DNA double-strand breaks in LUAD cells and an enhanced radiosensitivity. The expression of p-AKT, p-GSK3β, and p-DNA-PKcs decreased in the knockdown group after radiotherapy, suggesting that cancer-IgG could affect radiotherapy resistance by mediating double-strand breaks damage repair in LUAD cells through the PI3K/AKT/DNA-PKcs pathway.

Conclusions

This study revealed that cancer-IgG regulates PI3K/AKT/DNA-PKcs signaling pathways to affect radioresistance of LUAD and associated with poor prognosis.

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.