Cell surface-associated anti-MUC1-derived signal peptide antibodies: implications for cancer diagnostics and therapy

Peptide-Based Vaccine against Breast Cancer: Recent Advances and Prospects

Breast cancer is considered the second-leading cancer after lung cancer and is the most prevalent cancer among women globally. Currently, cancer immunotherapy via vaccine has gained great attention due to specific and targeted immune cell activity that creates a potent immune response, thus providing long-lasting protection against the disease. Despite peptides being very susceptible to enzymatic degradation and poor immunogenicity, they can be easily customized with selected epitopes to induce a specific immune response and particulate with carriers to improve their delivery and thus overcome their weaknesses. With advances in nanotechnology, the peptide-based vaccine could incorporate other components, thereby modulating the immune system response against breast cancer. Considering that peptide-based vaccines seem to show remarkably promising outcomes against cancer, this review focuses on and provides a specific view of peptide-based vaccines used against breast cancer. Here, we discuss the benefits associated with a peptide-based vaccine, which can be a mainstay in the prevention and recurrence of breast cancer. Additionally, we also report the results of recent trials as well as plausible prospects for nanotechnology against breast cancer.

Multiple Myeloma Therapy: Emerging Trends and Challenges

Multiple myeloma (MM) is a complex hematologic malignancy characterized by the uncontrolled proliferation of clonal plasma cells in the bone marrow that secrete large amounts of immunoglobulins and other non-functional proteins. Despite decades of progress and several landmark therapeutic advancements, MM remains incurable in most cases. Standard of care frontline therapies have limited durable efficacy, with the majority of patients eventually relapsing, either early or later. Induced drug resistance via up-modulations of signaling cascades that circumvent the effect of drugs and the emergence of genetically heterogeneous sub-clones are the major causes of the relapsed-refractory state of MM. Cytopenias from cumulative treatment toxicity and disease refractoriness limit therapeutic options, hence creating an urgent need for innovative approaches effective against highly heterogeneous myeloma cell populations. Here, we present a comprehensive overview of the current and future treatment paradigm of MM, and highlight the gaps in therapeutic translations of recent advances in targeted therapy and immunotherapy. We also discuss the therapeutic potential of emerging preclinical research in multiple myeloma.

Membrane-associated mucins of the human ocular surface in health and disease

Mucins are a family of high molecular weight, heavily-glycosylated proteins produced by wet epithelial tissues, including the ocular surface epithelia. Densely-packed O-linked glycan chains added post-translationally confer the biophysical properties of hydration, lubrication, anti-adhesion and repulsion. Membrane-associated mucins (MAMs) are the distinguishing components of the mucosal glycocalyx. At the ocular surface, MAMs maintain wetness, lubricate the blink, stabilize the tear film, and create a physical barrier to the outside world. In addition, it is increasingly appreciated that MAMs function as cell surface receptors that transduce information from the outside to the inside of the cell. Recently, our team published a comprehensive review/perspectives article for molecular scientists on ocular surface MAMs, including previously unpublished data and analyses on two new genes MUC21 and MUC22, as well as new MAM functions and biological roles, comparing human and mouse (PMID: 31493487). The current article is a refocus for the audience of The Ocular Surface. First, we update the gene and protein information in a more concise form, and include a new section on glycosylation. Next, we discuss biological roles, with some new sections and further updating from our previous review. Finally, we provide a new chapter on MAM involvement in ocular surface disease. We end this with discussion of an emerging mechanism responsible for damage to the epithelia and their mucosal glycocalyces: the unfolded protein response (UPR). The UPR offers a novel target for therapeutic intervention.

A signal peptide derived from Hsp60 induces protective cytotoxic T lymphocyte immunity against lymphoid malignancies independently of TAP and classical MHC-I

Hsp60sp, a signal peptide derived from the leader sequence of heat shock protein 60 kDa (Hsp60), is a Qa-1/HLA-E-binding peptide. We previously showed that Hsp60sp-specific CD8⁺ T cells are involved in the immunoregulation of autoimmune diseases by controlling the response of self-reactive lymphocytes. Here, we report that Hsp60sp-specific CD8⁺ T cells killed malignant lymphocytes in vitro independently of transporter associated with antigen processing (TAP) and classical MHC-I expression. Induction of this cytotoxic T lymphocyte (CTL) response in vivo, either by adoptive transfer of in vitro-amplified CTLs or peptide-loaded dendritic cell immunization, resulted in effective control of lymphoid tumors, including TAP- or classical MHC-I-deficient cells. Hsp60sp-specific immune activation combined with programmed cell death protein 1 (PD-1) blocking synergistically restrained mouse lymphoma development. Importantly, Hsp60sp-specific CD8⁺ T cells did not negatively affect normal tissues and cells. Our data suggest that Hsp60sp-based immunotherapy is an inviting strategy to control lymphoid malignancies.

miR-485-5p inhibits the progression of breast cancer cells by negatively regulating MUC1

OBJECTIVE

To investigate the mechanism of miR-485-5p inhibiting breast cancer cells by targeting MUC1.

METHODS

Differentially expressed genes (DEGs) in breast cancer tissues were analyzed using breast cancer tissue microarrays (TMA) in the GEO database. Differential expression of MUC1 in breast cancer tissue samples was detected by TCGA database. qRT-PCR was used to detect the expression of MUC1 and miR-485-5p in human normal breast epithelial cell lines and human breast cancer cell lines. Bioinformatics was applied to analyze targeted binding site of miR-485-5p and MUC1 and their targeted relationship was identified by dual luciferase assay. The proliferation ability of breast cancer cells was detected by CCK-8 assay. Cell apoptosis was detected by flow cytometry. The ability of cell migration was measured by scratch healing test. Transwell assay was used to detect the invasion ability of cells. The protein expression levels of MUC1 and EMT-related molecules (E-cadherin, N-cadherin and Vimentin) were detected by Western blot.

RESULTS

MUC1 was highly expressed in breast cancer tissue samples and breast cancer cell lines, while miR-485-5p was lowly expressed. Overexpression of miR-485-5p inhibits cell viability and invasion and migration of breast cancer cell line MCF-7 and promotes apoptosis. The same results were obtained by silencing the expression of MUC1. MiR-485-5p targets to bind to the 3'-UTR region of MUC1 and negatively regulates the expression of MUC1. Overexpressing MUC1 while overexpressing miR-485-5p reversed the inhibitory effect of miR-485-5p on breast cancer and inhibited EMT.

CONCLUSION

MiR-485-5p can down-regulate the expression of MUC1, thus inhibit the proliferation, invasion and migration of breast cancer cells and promote cell apoptosis.

Expression in algae of a chimeric protein carrying several epitopes from tumor associated antigens

Immunotherapies for cancer treatment constitute promising avenues to fight this global health issue. Algae can be used as both biofactories and delivery vehicles of vaccines; having low cost, fast growth, enhanced safety, and adjuvant effects as advantages. In the present study a multiepitope protein, called BCB, was designed as an attractive approach to develop new cancer immunotherapies. The BCB protein targets epitopes from the following tumor-associated antigens: human epidermal growth factor receptor-2 (HER2), mucin-like glycoprotein 1 (MUC1), Wilms' tumor antigen (WT1), and mammaglobin. Moreover, the BCB protein is based on the B subunit of the heat labile E. coli enterotoxin as immunogenic carrier to brake tolerance against self-antigens. A synthetic BCB-coding gene was obtained and expressed in Schizochytrium sp. using the Algevir system. The BCB protein was successfully expressed in transformed algae at levels up to 637 μg/g fresh weight, retaining the GM1-binding activity. The algae-made BCB showed reactivity towards an anti-serum against the tumor cell line 4T1; evidencing its antigenicity. Moreover the immunogenicity was evidenced in mice immunized with BCB, which developed serum IgG antibodies reacting against the 4T1 lysate. This study constitutes the first step in the development of innovative algae-based vaccines against cancer.

Nondestructive Analysis of Tumor-Associated Membrane Protein Integrating Imaging and Amplified Detection in situ Based on Dual-Labeled DNAzyme

Comprehensive analysis of the expression level and location of tumor-associated membrane proteins (TMPs) is of vital importance for the profiling of tumor cells. Currently, two kinds of independent techniques, i.e. ex situ detection and in situ imaging, are usually required for the quantification and localization of TMPs respectively, resulting in some inevitable problems.

Methods: Herein, based on a well-designed and fluorophore-labeled DNAzyme, we develop an integrated and facile method, in which imaging and quantification of TMPs in situ are achieved simultaneously in a single system. The labeled DNAzyme not only produces localized fluorescence for the visualization of TMPs but also catalyzes the cleavage of a substrate to produce quantitative fluorescent signals that can be collected from solution for the sensitive detection of TMPs.

Results: Results from the DNAzyme-based in situ imaging and quantification of TMPs match well with traditional immunofluorescence and western blotting. In addition to the advantage of two-in-one, the DNAzyme-based method is highly sensitivity, allowing the detection of TMPs in only 100 cells. Moreover, the method is nondestructive. Cells after analysis could retain their physiological activity and could be cultured for other applications.

Conclusion: The integrated system provides solid results for both imaging and quantification of TMPs, making it a competitive method over some traditional techniques for the analysis of TMPs, which offers potential application as a toolbox in the future.

Novel Antigen Targets for Immunotherapy of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) was the first malignancy for which immunotherapy, in the form of allogeneic hematopoietic stem cell transplantation (allo-HSCT), was integrated into the standard of care. Allo-HSCT however is an imperfect therapy associated with significant morbidity and mortality while offering only incomplete prevention of AML clinical relapse. These limitations have motivated the search for AML-related antigens that might be used as more specific and effective targets of immunotherapy. While historically such investigations have focused on protein targets expressed uniquely in AML or at significantly higher levels than in normal tissues, this article will review recent discoveries which have identified a novel selection of potential antigen targets for AML immunotherapy, such as non-protein targets including lipids and carbohydrates, neo-antigens created from genetic somatic mutations or altered splicing and post-translational modification of protein targets, together with innovative ways to target overexpressed protein targets presented by cell surface peptide-MHC complexes. These novel antigens represent promising candidates for further development as targets of AML immunotherapy.

Binding of circulating anti-MUC1 antibody and serum MUC1 antigen in stage IV breast cancer

The present study aimed to investigate the binding of circulating mucin 1 (MUC1) antibody with serum MUC1 antigen in stage IV breast cancer. Serum samples of 61 patients with stage IV breast cancer and 64 patients with early-stage breast cancer were collected. The anti‑MUC1 antibody (IgG) and MUC1 antigen (cancer antigen 15‑3; Ca15‑3) were detected using an indirect enzyme-linked immunosorbent assay (I‑ELISA) and ELISA, respectively. The MUC1 IgG affinity was detected using a urea degradation combining ELISA. Western blot analysis and an inhibition test were performed for verification of the binding of anti‑MUC1 IgG with MUC1 antigen, and their correlation was analyzed. The results showed that there was a negative correlation between anti‑MUC1 IgG and CA15‑3 antigen in stage IV breast cancer when positive CA15‑3 antigen and/or anti‑MUC1 IgG were selected (r=‑0.417; P=0.0044). The positive anti‑MUC1 IgG with positive Ca15‑3 antigen was more common in stage IV breast cancer, compared with early‑stage breast cancer (χ2=4.629; P=0.031), however, Ca15‑3 antigen positivity was higher in stage IV breast cancer, compared with early‑stage breast cancer (χ2=10.58; P=0.001). Anti‑MUC1 IgG was able to bind to the MUC1 antigen in stage IV breast cancer. No differences in the 8R-MUCPT inhibition ratio were found between the two groups (P=0.778), and there were no differences in the affinity of anti‑MUC1 IgG (P=0.873). In stage IV breast cancer, circulating anti‑MUC1 antibody was found to bind serum MUC1 antigen, although their compatibility was low. No significant difference was found in the affinity of the anti‑MUC1 antibody between stage IV breast cancer and early‑stage breast cancer.

Peptide Antibodies in Clinical Laboratory Diagnostics

Peptide antibodies, with their high specificities and affinities, are invaluable reagents for peptide and protein recognition in biological specimens. Depending on the application and the assay, in which the peptide antibody is to used, several factors influence successful antibody production, including peptide selection and antibody screening. Peptide antibodies have been used in clinical laboratory diagnostics with great success for decades, primarily because they can be produced to multiple targets, recognizing native wildtype proteins, denatured proteins, and newly generated epitopes. Especially mutation-specific peptide antibodies have become important as diagnostic tools in the detection of various cancers. In addition to their use as diagnostic tools in malignant and premalignant conditions, peptide antibodies are applied in all other areas of clinical laboratory diagnostics, including endocrinology, hematology, neurodegenerative diseases, cardiovascular diseases, infectious diseases, and amyloidoses.

TG4010: a vaccine with a therapeutic role in cancer

One of the strategies to enhance immune response against tumors has been the use of vaccines against tumor-associated antigens (TAAs). MUC1 is a TAA that is overexpressed in many malignancies being linked to worse prognosis. Moreover, tumor MUC1 is hypoglycosylated revealing new epitopes that are antigenic and potential T-cell targets. TG4010 is a recombinant viral vaccine targeting MUC1, also encoding for IL-2. TG4010 has been tested in Phase I-II trials demonstrating a consistent safety profile with mild local reactions as main side effect. These studies have confirmed immune responses to the vaccine product. Clinical efficacy has been observed mainly in patients with non-small-cell lung cancer in combination with chemotherapy. Peripheral activated NK cells are currently being validated as biomarkers of response.

Nonviral oncogenic antigens and the inflammatory signals driving early cancer development as targets for cancer immunoprevention

Cancer immunoprevention is an emerging field that holds much promise. Within the past 20 years, prophylactic vaccines have been implemented on the population level for the immunoprevention of carcinomas induced by viruses, specifically hepatitis B virus (HBV) and human papillomavirus (HPV) infection. Armed with the success of prophylactic vaccines that prevent viral-induced tumors, the field must overcome its next hurdle: to develop robust prophylactic vaccines that prevent the remaining >80% of human cancers not induced by viral infection. In this review, we discuss some of the most promising non-virus-associated prophylactic vaccines that target endogenous neoantigens, including the earliest oncogene products, altered mucin 1 (MUC1) and α-enolase (ENO1), all of which produce new targets in the earliest stages of nonviral-induced tumorigenesis. We also highlight a novel attenuated Listeria monocytogenes-based vaccine expressing mutant oncogene Kras(G12D) (LM-Kras) effective in a pancreatic cancer model. A novel chimeric human/rat HER-2 plasmid vaccine (HuRT-DNA vaccine) effective in a breast cancer model is also discussed. In addition to prophylactic vaccine developments, this review highlights the potential use of classic drugs, such as aspirin and metformin, as chemopreventive agents that can potentially be used as adjuvants to enhance the anticancer immunogenicity and efficacy of noninfectious prophylactic vaccines by modulating the inflammatory pathways within the early tumor microenvironment (TME) that propels tumorigenesis. Finally, timing of prophylactic vaccine administration is critical to its immunopreventive efficacy, providing a necessary role of current and emerging biomarkers for cancer screening and early cancer detection.

Dual-color labeled anti-mucin 1 antibody for imaging of ovarian cancer: A preliminary animal study

To investigate the feasibility of the anti-mucin 1 (anti-MUC1/CD227) antibody in the fluorescent imaging of ovarian cancer, the CD227 antibody and a control IgG antibody were labeled with a near-infrared dye [Cy5.5-N-hydroxysuccinimide (NHS)] and a green dye (fluorescein-NHS). In vivo fluorescence images were obtained at 4, 12 and 36 h after injection of the probes into OVCAR3 tumor-bearing mice. The tumor to background ratios were calculated for both probes. Ex vivo fluorescence images were obtained following sacrifice at 36 h. After conjugation to Cy5.5 and fluorescein, the dual-color labeled CD227 probe (Ab-FL-Cy5.5) could be visualized by both green and near-infrared fluorescence. Uptake by the tumors was higher for the Ab-FL-Cy5.5 than for the IgG-Cy5.5 probe. All tumors could be visualized by in vivo imaging with an acceptable tumor to background ratio. Ex vivo studies demonstrated the advantages of using green fluorescence imaging to guide the resection of tumor tissues. These preliminary data indicate that the Ab-FL-Cy5.5 probe is promising for further tumor imaging applications and clinical translation.

The use of signal peptide domains as vaccine candidates

Signal peptide (SP) domains have a common motif but also sequence specific features. This knowledge was mainly ignored by immunologists who considered SP as generic, short-lived, targeting sequences. Consequently, while SP-derived MHC class I, class II and HLA-E epitopes have been isolated, their use as antigen-specific vaccine candidates (VCs) was mostly neglected. Recently we demonstrated the rational of selecting entire SP domains as multi-epitope long peptide VCs based on their high T and B-cell epitope densities. This review summarizes preclinical and clinical results demonstrating the various advantages of human SP domain VCs derived from both bacterial and tumor antigens. Such vaccine design provides for a straightforward, yet unique immunotherapeutic means of generating robust, non-toxic, diversified, combined antigen-specific CD4+/CD8+ T/B-cell immunity, irrespective of patient HLA repertoire also in disease associated transporter-associated with antigen processing (TAP) deficiencies. Subsequent clinical trials will further assess the full potential of this approach.

Inhibition of KL-6/MUC1 glycosylation limits aggressive progression of pancreatic cancer

AIM: To evaluate the significance of KL-6/MUC1 (a type of MUC1) glycosylation in pancreatic cancer progression.

METHODS: KL-6/MUC1 expression was detected by immunohistochemistry in 48 patients with pancreatic duct cell carcinoma. The N-/O-glycosylation inhibitors (tunicamycin and benzyl-N-acetyl-α-galactosaminide) were then used to interfere with KL-6/MUC1 glycosylation in two pancreatic carcinoma cell lines, and the effects on KL-6/MUC1 expression, and cell adhesion and invasion were determined. In addition, protein expression of epithelial-mesenchymal transition markers, E-cadherin and vimentin, were evaluated in cells after treatment with glycosylation inhibitors.

RESULTS: Overexpression of KL-6/MUC1 was found in all pancreatic cancer tissues, but not in the surrounding normal pancreatic tissues. The expression profile of KL-6/MUC1 was significantly decreased after treatment with the inhibitors. The adhesion and invasive ability of cancer cells were significantly decreased after drug treatment, and increased E-cadherin and decreased vimentin expression were found.

CONCLUSION: KL-6/MUC1 glycosylation is involved in pancreatic cancer metastasis and invasion. Therapeutic strategies which target this may help control the aggressive behavior of pancreatic cancer cells.