Canonical and truncated transglutaminase-2 regulate mucin-1 expression and androgen independency in prostate cancer cell lines

The Glycopeptide PV-PS A1 Immunogen Elicits Both CD4+ and CD8+ Responses

BACKGROUND/OBJECTIVES

The MHCII-dependent, CD4+ T-cell zwitterionic polysaccharide PS A1 has been investigated as a promising carrier for vaccine development because it can induce an MHCII-dependent CD4+ response towards a variety of tumor-associated carbohydrate antigens (TACAs). However, PS A1 cannot elicit cytotoxic T lymphocytes through MHCI, which may or may not hamper its potential clinical use in cancer, infectious and viral vaccine development. This paper addresses PS A1 MHCI independence through the introduction of an MHCI epitope, the poliovirus (PV) peptide, to establish an MHCI- and MHCII-dependent vaccine.

METHODS

We synthesized a glycopeptide construct targeting the Thomsen-nouveau TACA (Tn-PV-PS A1) and a control Tn-PV peptide. C57BL/6 mice were immunized with both constructs, and the resulting T-cells were extracted from spleens.

RESULTS

Through cell proliferation assays, we show that Tn-PV-PS A1 elicits a robust CD4+ and CD8+ immune response. The resulting cytotoxic T lymphocytes are specific towards Tn-PV and trigger cell lysis of Tn-expressing EL4 cells.

CONCLUSIONS

This study confirms PV-PS A1 as a robust MHCI- and MHCII-dependent carrier. This is the first report of MHCI dependence in a zwitterionic polysaccharide.

MUC1 expression is associated with ST3GAL2 and negatively correlated with the androgen receptor in castration-resistant prostate cancer

Stage-specific embryonic antigen-4 (SSEA-4) is a developmentally regulated antigen, while expression level of SSEA-4 and / or its synthase ST3GAL2 is associated with prognosis in various malignancies. We have reported a prominent increase of SSEA-4 in castration-resistant prostate cancer (CRPC) and its negative correlation with the androgen receptor (AR). Meanwhile, loss of AR has increased to approximately 30% with the growing use of androgen receptor signaling inhibitor for metastatic CRPC (mCRPC). However, monitoring the progression status of AR-negative prostate cancer is a challenge because it does not produce prostate-specific antigen. Based on the negative relationship of expression between AR and SSEA-4, we hypothesized that a soluble molecule synchronized with SSEA-4 in expression could be a serum marker candidate for AR-negative prostate cancer. Thus, we investigated the molecular background of SSEA-4 expression by ST3GAL2-knockout in DU145 cells. Here we show that MUC1 is identified as a molecule associated with ST3GAL2 and expressed in AR-negative prostate cancer. A negative correlation of expression between AR and MUC1 was observed in prostate cancer cell lines and CRPC tissues. The average rate of MUC1 expression was nearly 60% in AR-negative prostate cancer cells in CRPC tissues. Level of serum CA15-3 (MUC1) was the highest in mCRPC among various stages and its higher level was associated with faster progression of mCRPC. Our results demonstrate that MUC1 is identified as a ST3GAL2-associated molecule and expressed in AR-negative CRPC cells. Furthermore, level of serum CA15-3 may reflect the progression status of mCRPC.

Research progress of MUC1 in genitourinary cancers

MUC1 is a highly glycosylated transmembrane protein with a high molecular weight. It plays a role in lubricating and protecting mucosal epithelium, participates in epithelial cell renewal and differentiation, and regulates cell adhesion, signal transduction, and immune response. MUC1 is expressed in both normal and malignant epithelial cells, and plays an important role in the diagnosis, prognosis prediction and clinical monitoring of a variety of tumors and is expected to be a new therapeutic target. This article reviews the structural features, expression regulation mechanism, and research progress of MUC1 in the development of genitourinary cancers and its clinical applications.

Targeting mRNA-coding genes in prostate cancer using CRISPR/Cas9 technology with a special focus on androgen receptor signaling

BACKGROUND

Prostate cancer is among prevalent cancers in men. Numerous strategies have been proposed to intervene with the important prostate cancer-related signaling pathways. Among the most promising strategies is CRISPR/Cas9 strategy. This strategy has been used to modify expression of a number of genes in prostate cancer cells.

AIMS

This review summarizes the most recent progresses in the application of CRISPR/Cas9 strategy in modification of prostate cancer-related phenotypes with an especial focus on pathways related to androgen receptor signaling.

CONCLUSION

CRISPR/Cas9 technology has successfully targeted several genes in the prostate cancer cells. Moreover, the efficiency of this technique in reducing tumor burden has been tested in animal models of prostate cancer. Most of targeted genes have been related with the androgen receptor signaling. Targeted modulation of these genes have affected growth of castration-resistant prostate cancer. PI3K/AKT/mTOR signaling and immune response-related genes have been other targets that have been successfully modulated by CRISPR/Cas9 technology in prostate cancer. Based on the rapid translation of this technology into the clinical application, it is anticipated that novel treatments based on this technique change the outcome of this malignancy in future.

Biological Implications and Functional Significance of Transglutaminase Type 2 in Nervous System Tumors

Transglutaminase type 2 (TG2) is the most ubiquitously expressed member of the transglutaminase family. TG2 catalyzes the transamidation reaction leading to several protein post-translational modifications and it is also implicated in signal transduction thanks to its GTP binding/hydrolyzing activity. In the nervous system, TG2 regulates multiple physiological processes, such as development, neuronal cell death and differentiation, and synaptic plasticity. Given its different enzymatic activities, aberrant expression or activity of TG2 can contribute to tumorigenesis, including in peripheral and central nervous system tumors. Indeed, TG2 dysregulation has been reported in meningiomas, medulloblastomas, neuroblastomas, glioblastomas, and other adult-type diffuse gliomas. The aim of this review is to provide an overview of the biological and functional relevance of TG2 in the pathogenesis of nervous system tumors, highlighting its involvement in survival, tumor inflammation, differentiation, and in the resistance to standard therapies.

The Potential of Extracellular Matrix- and Integrin Adhesion Complex-Related Molecules for Prostate Cancer Biomarker Discovery

Prostate cancer is among the top five cancer types according to incidence and mortality. One of the main obstacles in prostate cancer management is the inability to foresee its course, which ranges from slow growth throughout years that requires minimum or no intervention to highly aggressive disease that spreads quickly and resists treatment. Therefore, it is not surprising that numerous studies have attempted to find biomarkers of prostate cancer occurrence, risk stratification, therapy response, and patient outcome. However, only a few prostate cancer biomarkers are used in clinics, which shows how difficult it is to find a novel biomarker. Cell adhesion to the extracellular matrix (ECM) through integrins is among the essential processes that govern its fate. Upon activation and ligation, integrins form multi-protein intracellular structures called integrin adhesion complexes (IACs). In this review article, the focus is put on the biomarker potential of the ECM- and IAC-related molecules stemming from both body fluids and prostate cancer tissue. The processes that they are involved in, such as tumor stiffening, bone turnover, and communication via exosomes, and their biomarker potential are also reviewed.