Cancer/testis Antigen MAGEA3 Interacts with STAT1 and Remodels the Tumor Microenvironment

Tissue factor pathway inhibitor-2 (TFPI-2)-an underappreciated partaker in cancer and metastasis

The coagulation system is known to play an important role in cancer development and metastasis, but the precise mechanisms by which it does so remain incompletely understood. With this in mind, we provide an updated overview of the effects of TFPI-2, a protease inhibitor, on cancer development and metastasis. TFPI-2 interacts with the thrombin cascade and also employs other mechanisms to suppress cancer growth and dissemination, which include extracellular matrix stabilization, promotion of caspase-mediated cell apoptosis, inhibition of angiogenesis and transduction of intracellular signals. Down-regulation of TFPI-2 expression is well documented in numerous types of neoplasms, mainly via promoter methylation. However, the exact role of TFPI-2 in cancer progression and possible approaches to up-regulate TFPI-2 expression warrant further studies. Strategies to reactivate TFPI-2 may represent a promising direction for future anticancer studies and therapy development.

Vasculogenic mimicry-associated novel gene signature predicted prognosis and response to immunotherapy in lung adenocarcinoma

BACKGROUNDS

It was highlighted by recent studies on the biological significance of vasculogenic mimicry (VM) in tumorigenicity and progression. However, it is unclear whether VM also plays a potential role in immune regulation and tumor microenvironment (TME) formation.

METHODS

To identify patterns of VM alterations and VM-associated genetic features in non-small cell lung adenocarcinoma, we have screened 309 VM regulators and performed consensus molecular typing by the NMF algorithm. The ssGSEA and CIBORSORT algorithms were employed to measure the relative infiltration of distinct immune cell subpopulations. Individual tumors with immune responses were evaluated for alteration patterns of VM with typing-based differential genes.

RESULTS

In 490 LUAD samples, two distinctive VM alteration patterns connected to different clinical outcomes and biochemical pathways were established. TME characterization showed that the observed VM patterns were primarily saturated with cell proliferation and metabolic pathways and higher in immune cell infiltration of the C1 type. Vasculogenic mimicry-related genes (VMRG) risk scores were constructed to divide patients with lung adenocarcinoma into subgroups with high and low scores. Patients with lower scores had better immunological scores and longer survival times. Upon further investigation, higher scores were positively correlated with higher tumor mutation burden (TMB), M1-type macrophages and immune checkpoint molecules. Nevertheless, in two other immunotherapy cohorts, individuals with lower scores had enhanced immune responses and long-lasting therapeutic benefits. Finally, we monitored the ANLN gene from the VMRG model, which was highly expressed in lung adenocarcinoma tissues and negatively correlated with prognosis; it was also highly expressed in lung adenocarcinoma cell lines, and knockdown of ANLN elicited low expression of VEGFA, MMP2 and MMP9.

CONCLUSION

This study highlights that VM modifications are significantly associated with the diversity and complexity of TME, revealing new features of the immune microenvironment in lung adenocarcinoma and providing a new strategy for immunotherapy. Screening ANLN as a critical target for vasculogenic mimicry in lung adenocarcinoma provides a novel perspective for the targeted treatment of lung adenocarcinoma.

Peptide vaccine from cancer-testis antigen ODF2 can potentiate the cytotoxic T lymphocyte infiltration through IL-15 in non-MSI-H colorectal cancer

About 85% of patients with colorectal cancer (CRC) have the non-microsatellite instability-high (non-MSI-H) subtype, and many cannot benefit from immune checkpoint blockade. A potential reason for this is that most non-MSI-H colorectal cancers are immunologically "cold" due to poor CD8⁺ T cell infiltration. In the present study, we screened for potential cancer-testis antigens (CTAs) by comparing the bioinformatics of CD8⁺ T effector memory (Tem) cell infiltration between MSI-H and non-MSI-H CRC. Two ODF2-derived epitope peptides, P433 and P609, displayed immunogenicity and increased the proportion of CD8⁺ T effector memory (Tem) cells in vitro and in vivo. The adoptive transfer of peptide pool-induced CTLs inhibited tumor growth and enhanced CD8⁺ T cell infiltration in tumor-bearing NOD/SCID mice. The mechanistic study showed that knockdown of ODF2 in CRC cells promoted interleukin-15 expression, which facilitated CD8⁺ T cell proliferation. In conclusion, ODF2, a CTA, was negatively correlated with CD8⁺ T cell infiltration in "cold" non-MSI-H CRC and was selected based on the results of bioinformatics analyses. The corresponding HLA-A2 restricted epitope peptide induced antigen-specific CTLs. Immunotherapy targeting ODF2 could improve CTA infiltration via upregulating IL-15 in non-MSI-H CRC. This tumor antigen screening strategy could be exploited to develop therapeutic vaccines targeting non-MSI-H CRC.

Biology of Cancer-Testis Antigens and Their Therapeutic Implications in Cancer

Tumour-specific antigens have been an area of interest in cancer therapy since their discovery in the middle of the 20th century. In the era of immune-based cancer therapeutics, redirecting our immune cells to target these tumour-specific antigens has become even more relevant. Cancer-testis antigens (CTAs) are a class of antigens with an expression specific to the testis and cancer cells. CTAs have also been demonstrated to be expressed in a wide variety of cancers. Due to their frequency and specificity of expression in a multitude of cancers, CTAs have been particularly attractive as cancer-specific therapeutic targets. There is now a rapid expansion of CTAs being identified and many studies have been conducted to correlate CTA expression with cancer and therapy-resistant phenotypes. Furthermore, there is an increasing number of clinical trials involving using some of these CTAs as molecular targets in pharmacological and immune-targeted therapeutics for various cancers. This review will summarise the current knowledge of the biology of known CTAs in tumorigenesis and the regulation of CTA genes. CTAs as molecular targets and the therapeutic implications of these CTA-targeted anticancer strategies will also be discussed.

Ex Vivo Model of Neuroblastoma Plasticity

Tumor plasticity is essential for adaptation to changing environmental conditions, in particular during the process of metastasis. In this study, we compared morphological and biochemical differences between LAN-1 neuroblastoma (NB) cells recovered from a subcutaneous xenograft primary tumor (PT) and the corresponding three generations of bone metastasis (BM I-III). Moreover, growth behavior, as well as the response to chemotherapy and immune cells were assessed. For this purpose, F-actin was stained, mRNA and protein expression assessed, and lactate secretion analyzed. Further, we measured adhesion to collagen I, the growth rate of spheroids in the presence and absence of vincristine, and the production of IL-6 by peripheral blood mononuclear cells (PBMCs) co-incubated with PT or BM I-III. Analysis of PT and the three BM generations revealed that their growth rate decreased from PT to BM III, and accordingly, PT cells reacted most sensitively to vincristine. In addition, morphology, adaption to hypoxic conditions, as well as transcriptomes showed strong differences between the cell lines. Moreover, BM I and BM II cells exhibited a significantly different ability to stimulate human immune cells compared to PT and BM III cells. Interestingly, the differences in immune cell stimulation corresponded to the expression level of the cancer-testis antigen MAGE-A3. In conclusion, our ex vivo model allows to analyze the adaption of tumor populations to different microenvironments and clearly demonstrates the strong alteration of tumor cell populations during this process.

Peptide-Based Vaccines in Clinical Phases and New Potential Therapeutic Targets as a New Approach for Breast Cancer: A Review

Breast cancer is the leading cause of death in women from 20 to 59 years old. The conventional treatment includes surgery, chemotherapy, hormonal therapy, and immunotherapy. This immunotherapy is based on administering monoclonal therapeutic antibodies (passive) or vaccines (active) with therapeutic purposes. Several types of vaccines could be used as potential treatments for cancer, including whole-cell, DNA, RNA, and peptide-based vaccines. Peptides used to develop vaccines are derived from tumor-associated antigens or tumor-specific antigens, such as HER-2, MUC1, ErbB2, CEA, FRα, MAGE A1, A3, and A10, NY-ESO-1, among others. Peptide-based vaccines provide some advantages, such as low cost, purity of the antigen, and the induction of humoral and cellular immune response. In this review, we explore the different types of vaccines against breast cancer with a specific focus on the description of peptide-based vaccines, their composition, immune response induction, and the description of new potential therapeutic targets.

Oncogenic activity and cellular functionality of melanoma associated antigen A3

Cancer testis antigen Melanoma associated antigen A3 (MAGE-A3) has been subject of research for many years. Being expressed in various tumor types and influencing proliferation, metastasis, and tumor pathogenicity, MAGE-A3 is an attractive target for cancer therapy, particularly because in healthy tissues, MAGE-A3 is only expressed in testes and placenta. MAGE-A3 acts as a cellular master regulator by stimulating E3 ubiquitin ligase tripartite motif-containing protein 28 (TRIM28), resulting in regulation of various cellular targets. These include tumor suppressor protein p53 and cellular energy sensor AMP-activated protein kinase (AMPK). The restricted expression of MAGE-A3 in tumor cells makes MAGE-A3 an attractive target for vaccine-based immune therapy. However, although phase I and phase II clinical trials involving MAGE-A3-specific immunotherapeutic interventions were promising, large phase III studies failed. This article gives an overview about the role of MAGE-A3 as a cellular master switch and discusses approaches to improve MAGE-A3-based immunotherapies.

Oncogenic cancer/testis antigens are a hallmarker of cancer and a sensible target for cancer immunotherapy

Increasing evidence shows that numerous cancer-testis antigens (CTAs) are uniquely overexpressed in various types of cancer and most CTAs are oncogenic. Overexpression of oncogenic CTAs promotes carcinogenesis, cancer metastasis, and drug resistance. Oncogenic CTAs are generally associated with poor prognosis in cancer patients and are an important hallmark of cancer, making them a crucial target for cancer immunotherapy. CTAs-targeted antibodies, vaccines, and chimeric antigen receptor-modified T cells (CAR-T) have recently been used in cancer treatment and achieved promising outcomes in the preclinical and early clinical trials. However, the efficacy of current CTA-targeted therapeutics is either moderate or low in cancer therapy. CTA-targeted cancer immunotherapy is facing enormous challenges. Several critical scientific problems need to be resolved: (1) the antigen presentation function of MHC-I protein is usually deficient in cancer patients, so that very low amounts of intracellular CTA epitopes are presented to tumor cell membrane surface, leading to weak immune response and subsequent immunity to CTAs; (2) various immunosuppressive cells are rich in tumor tissues leading to diminished tumor immunity; (3) the tumor tissue microenvironment markedly reduces the efficacy of cancer immunotherapy. In the current review paper, the authors propose new strategies and approaches to overcome the barriers of CTAs-targeted immunotherapy and to develop novel potent immune therapeutics against cancer. Finally, we highlight that the oncogenic CTAs have high tumor specificity and immunogenicity, and are sensible targets for cancer immunotherapy. We predict that CTAs-targeted immunotherapy will bring about breakthroughs in cancer therapy in the near future.

Cancer/testis antigens: from serology to mRNA cancer vaccine

Cancer/testis antigens (CTAs) are a group of tumor antigens expressed in numerous cancer tissues, as well as in the testis and placental tissues. There are over 200 CTAs supported by serology and expression data. The expression patterns of CTAs reflect the similarities between the processes of gametogenesis and tumorigenesis. It is notable that CTAs are highly expressed in three types of cancers (lung cancer, bladder cancer, and skin cancer), all of which have a metal etiology. Here, we review the expression, regulation, and function of CTAs and their translational prospects as cancer biomarkers and treatment targets. Many CTAs are highly immunogenic, tissue-specific, and frequently expressed in cancer tissues but not under physiological conditions, rendering them promising candidates for cancer detection. Some CTAs are associated with clinical outcomes, so they may serve as prognostic biomarkers. A small number of CTAs are membrane-bound, making them ideal targets for chimeric antigen receptor (CAR) T cells. Mounting evidence suggests that CTAs induce humoral or cellular immune responses, providing cancer immunotherapeutic opportunities for T-cell receptors (TCRs), CAR T cell, antibody-based therapy and peptide- or mRNA-based vaccines. Indeed, CTAs are the dominating non-mutated targets in mRNA cancer vaccine development. Clinical trials on CTA TCR and vaccines have shown effectiveness, safety, and tolerance, but these successes are limited to a small number of patients. In-depth studies on CTA expression and function are needed to improve CTA-based immunotherapy.

Expression of STAT1 is positively correlated with PD-L1 in human ovarian cancer

Signal transducer and activator of transcription 1 (STAT1) is related to the immune microenvironment of tumorigenesis. The programmed cell death 1 (PD-1) and its ligand (PD-L1) have been reported to be important in immunotherapy by mediating tumor immune evasion. Blocking the PD-1/PD-L1 pathway can restore the endogenous anti-tumor immune response. This study aimed to examine the expression of STAT1, PD-1, and PD-L1 and the correlation between selected markers in human epithelial ovarian cancer (EOC). The results showed that malignant tumors contained more STAT1, PD-1, and PD-L1 positive cells. The expression of STAT1 and PD-L1 was associated with age, whereas PD-1 and PD-L1 associated with histopathological type, in patients with ovarian tumors. Moreover, the expression of STAT1 was found to be associated with disease stages and the grade of serous carcinoma. STAT1 expression was higher in OC cells than normal ovarian surface epithelial cells and was positively correlated with PD-L1 expression. The knockdown of STAT1 decreased PD-L1 expression, whereas overexpression of STAT1 increased PD-L1 expression. Furthermore, the expression of STAT1, PD-1, and PD-L1 was lower in paclitaxel-resistant cells than sensitive cells. Finally, STAT1 affected the overall survival and progression-free survival of patients with EOC. These findings suggest that STAT1, PD-1, and PD-L1 are the tissue markers of EOC and imply the possibility that the high level of STAT1, PD-1, and PD-L1 may favor the checkpoint immunotherapy in patients with EOC, but may have a limit in paclitaxel-resistant patients because of the low expression of STAT1, PD-1, and PD-L1 in paclitaxel-resistant cells.

Immunological and functional aspects of MAGEA3 cancer/testis antigen

Identification of ectopic gene activation in cancer cells serves as a basis for both gene signature-guided tumor targeting and unearthing of oncogenic mechanisms to expand the understanding of tumor biology/oncogenic process. Proteins expressed only in germ cells of testis and/or placenta (immunoprivileged organs) and in malignancies are called cancer testis antigens; they are antigenic because of the lack of antigen presentation by those specific cell types (germ cells), which limits the exposure of the proteins to the immune cells. Since the Cancer Testis Antigens (CTAs) are immunogenic and expressed in a wide variety of cancer types, CT antigens have become interesting target for immunotherapy against cancer. Among CT antigens MAGEA family is reported to have 12 members (MAGEA1 to MAGEA12). The current review highlights the studies on MAGEA3 which is a CT antigen and reported in almost all types of cancer. MAGEA3 is well tried for cancer immunotherapy. Recent advances on its functional and immunological aspect warranted much deliberation on effective therapeutic approach, thus making it a more interesting target for cancer therapy.

Highly expressed STAT1 contributes to the suppression of stemness properties in human paclitaxel-resistant ovarian cancer cells

Signal transducer and activator of transcription-1 (STAT1) is an important factor in various cellular processes. The cancer stem cell (CSC) is considered as a tumor-initiating cell that drives the inner hierarchy in many cancers including epithelial ovarian cancer (EOC). Here, we explored for the first time the regulation of STAT1 on stemness properties in chemoresistant EOC cells. The paclitaxel (PTX)-resistant EOC cell line (OV3R-PTX) was derived from PTX-sensitive OVCAR-3 cells treated by the PTX regimen. A single cell clone OV3R-PTX-B4 was selected by fluorescence-activated cell sorting. PTX-resistant cells grew slowly in conventional 2D and 3D cultures, but tumor xenograft with PTX-resistant cells grew fast in nude mice. Interestingly, OV3R-PTX-B4 cells shared the characteristics of CSCs and stemness properties were found to be increased in the non-adherent spheroid culture system. The PTX-resistant cells had a high expression of CSC-related markers and low expression of STAT1 that had a high methylation level of CpG in its promoter region. Overexpressed STAT1 suppressed stemness properties, cell proliferation, and colony formation and favored the overall survival of patients with EOC. In summary, these data indicate a regulatory mechanism of STAT1 underlying drug resistance and provide a potential therapeutic application for EOC patients with PTX resistance.

Predicting STAT1 as a prognostic marker in patients with solid cancer

Background:

Aberrant activities of signal transducer and activator of transcription 1 (STAT1) have been implicated in cancer development. However, the prognostic value of STAT1 remains unclear. This report identified the role of STAT1 in prognosis in patients with solid cancer through open literature and The Cancer Genome Atlas (TCGA) database.

Methods:

Published articles were obtained from PubMed, Web of Science, and Embase databases according to a search strategy up to October 2019. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were extracted to assess the prognostic factors of patients. TCGA datasets were used to explore the prognostic value of STAT1 in various cancers.

Results:

A total of 15 studies incorporating 2839 patients with solid cancers were included. Pooled data showed that overexpressed STAT1 favored long overall survival (OS) (HR = 0.604, 95% CI = 0.431–0.846, p = 0.003) and disease-specific survival (DSS) (HR = 0.650, 95% CI = 0.512–0.825, p = 0.000). In subgroup analyses, highly expressed STAT1 was correlated with long OS of patients with high-grade serous ovarian cancer and oral squamous cell carcinoma. Data extracted from TCGA datasets unveiled that STAT1 expression was significantly higher in 12 cancers (e.g. bladder and breast) than their adjacent normal tissues. Again, highly expressed STAT1 favored long OS of patients with ovarian cancer as well as rectum adenocarcinoma, sarcoma, and skin cutaneous melanoma. However, in renal carcinoma, brain lower grade glioma, lung adenocarcinoma, and pancreatic cancer, highly expressed STAT1 was correlated with poor OS of patients. Particularly in renal carcinoma, increased STAT1 expression was associated with high grade, later stage, large tumor size, and lymph node and distant metastasis.

Conclusion:

STAT1 has been identified to have prognostic value in patients with solid cancer. Highly expressed STAT1 may predict prognosis in cancer patients based on their tumor types.