Mucin in cancer: a stealth cloak for cancer cells

MUC1 promotes cervical squamous cell carcinoma through ERK phosphorylation-mediated regulation of ITGA2/ITGA3

In contrast to the decreasing trends in developed countries, the incidence and mortality rates of cervical squamous cell carcinoma in China have increased significantly. The screening and identification of reliable biomarkers and candidate drug targets for cervical squamous cell carcinoma are urgently needed to improve the survival rate and quality of life of patients. In this study, we demonstrated that the expression of MUC1 was greater in neoplastic tissues than in non-neoplastic tissues of the cervix, and cervical squamous cell carcinoma patients with high MUC1 expression had significantly worse overall survival than did those with low MUC1 expression, indicating its potential for early diagnosis of cervical squamous cell carcinoma. Next, we explored the regulatory mechanism of MUC1 in cervical squamous cell carcinoma. MUC1 could upregulate ITGA2 and ITGA3 expression via ERK phosphorylation, promoting the proliferation and metastasis of cervical cancer cells. Further knockdown of ITGA2 and ITGA3 significantly inhibited the tumorigenesis of cervical cancer cells. Moreover, we designed a combination drug regimen comprising MUC1-siRNA and a novel ERK inhibitor in vivo and found that the combination of these drugs achieved better results in animals with xenografts than did MUC1 alone. Overall, we discovered a novel regulatory pathway, MUC1/ERK/ITGA2/3, in cervical squamous cell carcinoma that may serve as a potential biomarker and therapeutic target in the future.

The research status and prospects of MUC1 in immunology

In immune processes, molecular - molecular interactions are complex. As MUC1 often appears to be an important molecule in inflammation and tumor immunity, it is necessary to summarize the leading countries, authors, journals, and the cooperation among these entities and, most importantly, to determine the main research directions related to MUC1 in this field and the associated research frontiers. A total of 3,397 related studies published from 2012-2021 were retrieved from the Web of Science core database. The search strategy is TS= (MUC1 OR Mucin-1) refined by WEB OF SCIENCE CATEGORY (IMMUNOLOGY) AND [excluding] PUBLICATION YEARS: (2022) AND DOCUMENT TYPES: (ARTICLE OR REVIEW) AND LANGUAGES: (ENGLISH) AND WEB OF SCIENCE INDEX: (Web of Science Core Collection. SCI), with a timespan of 2012 to 2021. Documented bibliometric visual analysis was performed by CiteSpace and VOSviewer. The number of studies has increased every year. There are 1,982 articles and 1,415 reviews from 89 countries and regions, 3,722 organizations, 1,042 journals, and 17,948 authors. The United States, China, and Germany are the major countries producing publications on this issue. The most published author is Finn OJ and the most influential author is June CH. The key words "chimeric antigen receptor" and "T-cell" highlight the current hot spots and future trends in this field. Research on MUC1 in the field of immunology is still evolving. Through the bibliometric analysis of the existing publications, the current research hotspots and future development trends in this field can be obtained.

A CRISPR activation screen identifies MUC-21 as critical for resistance to NK and T cell-mediated cytotoxicity

BACKGROUND

Immunotherapy has significantly advanced cancer treatments, but many patients do not respond to it, partly due to immunosuppressive mechanisms used by tumor cells. These cells employ immunosuppressive ligands to evade detection and elimination by the immune system. Therefore, the discovery and characterization of novel immunosuppressive ligands that facilitate immune evasion are crucial for developing more potent anti-cancer therapies.

METHODS

We conducted gain-of-function screens using a CRISPRa (CRISPR activation) library that covered the entire human transmembrane sub-genome to identify surface molecules capable of hindering NK-mediated cytotoxicity. The immunosuppressive role and mechanism of MUC21 were validated using NK and T cell mediated cytotoxicity assays. Bioinformatics tools were employed to assess the clinical implications of mucin-21 (MUC21) in cancer cell immunity.

RESULTS

Our genetic screens revealed that MUC21 expression on cancer cell surfaces inhibits both the cytotoxic activity of NK cells and antibody-dependent cellular cytotoxicity, but not affecting complement-dependent cytotoxicity. Additionally, MUC21 expression hinders T cell activation by impeding antigen recognition, thereby diminishing the effectiveness of the immune checkpoint inhibitor, anti-PD-L1. Moreover, MUC21 expression suppress the antitumor function of both CAR-T cells and CAR-NK cells. Mechanistically, MUC21 facilitates immune evasion by creating steric hindrance, preventing interactions between cancer and immune cells. Bioinformatics analysis revealed elevated MUC21 expression in lung cancer, which correlated with reduced infiltration and activation of cytotoxic immune cells. Intriguingly, MUC21 expression was higher in non-small cell lung cancer (NSCLC) tumors that were non-responsive to anti-PD-(L)1 treatment compared to responsive tumors.

CONCLUSIONS

These findings indicate that surface MUC21 serves as a potent immunosuppressive ligand, shielding cancer cells from NK and CD8+T cell attacks. This suggests that inhibiting MUC21 could be a promising strategy to improve cancer immunotherapy.

Mucin Glycans: A Target for Cancer Therapy

Mucin glycans are an important component of the mucus barrier and a vital defence against physical and chemical damage as well as pathogens. There are 20 mucins in the human body, which can be classified into secreted mucins and transmembrane mucins according to their distributions. The major difference between them is that secreted mucins do not have transmembrane structural domains, and the expression of each mucin is organ and cell-specific. Under physiological conditions, mucin glycans are involved in the composition of the mucus barrier and thus protect the body from infection and injury. However, abnormal expression of mucin glycans can lead to the occurrence of diseases, especially cancer, through various mechanisms. Therefore, targeting mucin glycans for the diagnosis and treatment of cancer has always been a promising research direction. Here, we first summarize the main types of glycosylation (O-GalNAc glycosylation and N-glycosylation) on mucins and the mechanisms by which abnormal mucin glycans occur. Next, how abnormal mucin glycans contribute to cancer development is described. Finally, we summarize MUC1-based antibodies, vaccines, radio-pharmaceuticals, and CAR-T therapies using the best characterized MUC1 as an example. In this section, we specifically elaborate on the recent new cancer therapy CAR-M, which may bring new hope to cancer patients.

Epigenetic insights into colorectal cancer: comprehensive genome-wide DNA methylation profiling of 294 patients in Korea

DNA methylation regulates gene expression and contributes to tumorigenesis in the early stages of cancer. In colorectal cancer (CRC), CpG island methylator phenotype (CIMP) is recognized as a distinct subset that is associated with specific molecular and clinical features. In this study, we investigated the genomewide DNA methylation patterns among patients with CRC. The methylation data of 1 unmatched normal, 142 adjacent normal, and 294 tumor samples were analyzed. We identified 40,003 differentially methylated positions with 6,933 (79.8%) hypermethylated and 16,145 (51.6%) hypomethylated probes in the genic region. Hypermethylated probes were predominantly found in promoter-like regions, CpG islands, and N shore sites; hypomethylated probes were enriched in open-sea regions. CRC tumors were categorized into three CIMP subgroups, with 90 (30.6%) in the CIMP-high (CIMP-H), 115 (39.1%) in the CIMP-low (CIMP-L), and 89 (30.3%) in the non-CIMP group. The CIMP-H group was associated with microsatellite instabilityhigh tumors, hypermethylation of MLH1, older age, and rightsided tumors. Our results showed that genome-wide methylation analyses classified patients with CRC into three subgroups according to CIMP levels, with clinical and molecular features consistent with previous data. [BMB Reports 2023; 56(10): 563-568].

Electrochemical biotool for the dual determination of epithelial mucins associated to prognosis and minimal residual disease in colorectal cancer

This work reports a dual immunoplatform for the simultaneous detection of two epithelial glycoproteins of the mucin family, mucin 1 (MUC1) and mucin 16 (MUC16), whose expression is related to adverse prognosis and minimal residual disease (MRD) in colorectal cancer (CRC). The developed immunoplatform involves functionalised magnetic microparticles (MBs), a set of specific antibody pairs (a capture antibody, cAb, and a biotinylated detector antibody b-dAb labelled with a streptavidin-horseradish peroxidase, Strep-HRP, polymer) for each target protein and amperometric detection at dual screen-printed carbon electrodes (SPdCEs) using the hydroquinone (HQ)/horseradish peroxidase (HRP)/H2O2 system. This dual immunoplatform allows, under the optimised experimental conditions, to achieve LOD values of 50 and 1.81 pg mL-1 (or mU mL-1) for MUC1 and MUC16, respectively, and adequate selectivity for the determination of the two targets in the clinic. The developed immunoplatform was employed to analyse CRC cell protein extracts (1.0 μg/determination) with different metastatic potential providing results in agreement with those obtained by blotting technologies but using affordable and applicable point-of-care instruments. This new biotool also emerges competitive in state-of-the-art electrochemical immunoplatforms seeking a compromise among simplicity, reduction of test time and analytical characteristics.

Chimeric antibody targeting unique epitope on onco-mucin16 reduces tumor burden in pancreatic and lung malignancies

Aberrantly expressed onco-mucin 16 (MUC16) and its post-cleavage generated surface tethered carboxy-terminal (MUC16-Cter) domain are strongly associated with poor prognosis and lethality of pancreatic (PC) and non-small cell lung cancer (NSCLC). To date, most anti-MUC16 antibodies are directed towards the extracellular domain of MUC16 (CA125), which is usually cleaved and shed in the circulation hence obscuring antibody accessibility to the cancer cells. Herein, we establish the utility of targeting a post-cleavage generated, surface-tethered oncogenic MUC16 carboxy-terminal (MUC16-Cter) domain by using a novel chimeric antibody in human IgG1 format, ch5E6, whose epitope expression directly correlates with disease severity in both cancers. ch5E6 binds and interferes with MUC16-associated oncogenesis, suppresses the downstream signaling pFAK(Y397)/p-p70S6K(T389)/N-cadherin axis and exert antiproliferative effects in cancer cells, 3D organoids, and tumor xenografts of both PC and NSCLC. The robust clinical correlations observed between MUC16 and N-cadherin in patient tumors and metastatic samples imply ch5E6 potential in targeting a complex and significantly occurring phenomenon of epithelial to mesenchymal transition (EMT) associated with disease aggressiveness. Our study supports evaluating ch5E6 with standard-of-care drugs, to potentially augment treatment outcomes in malignancies inflicted with MUC16-associated poor prognosis.

Emerging applications of cancer bacteriotherapy towards treatment of pancreatic cancer

Pancreatic cancer is a highly aggressive form of cancer with a five-year survival rate of only ten percent. Pancreatic ductal adenocarcinoma (PDAC) accounts for ninety percent of those cases. PDAC is associated with a dense stroma that confers resistance to current treatment modalities. Increasing resistance to cancer treatments poses a challenge and a need for alternative therapies. Bacterial mediated cancer therapies were proposed in the late 1800s by Dr. William Coley when he injected osteosarcoma patients with live streptococci or a fabrication of heat-killed Streptococcus pyogenes and Serratia marcescens known as Coley's toxin. Since then, several bacteria have gained recognition for possible roles in potentiating treatment response, enhancing anti-tumor immunity, and alleviating adverse effects to standard treatment options. This review highlights key bacterial mechanisms and structures that promote anti-tumor immunity, challenges and risks associated with bacterial mediated cancer therapies, and applications and opportunities for use in PDAC management.

Predictive value of intratumoral-metabolic heterogeneity derived from 18F-FDG PET/CT in distinguishing microsatellite instability status of colorectal carcinoma

Purpose/background

Microsatellite instability (MSI) status is a significant biomarker for the response to immune checkpoint inhibitors, response to 5-fluorouracil-based adjuvant chemotherapy, and prognosis in colorectal carcinoma (CRC). This study investigated the predictive value of intratumoral-metabolic heterogeneity (IMH) and conventional metabolic parameters derived from 18F-FDG PET/CT for MSI in patients with stage I-III CRC.

Methods

This study was a retrospective analysis of 152 CRC patients with pathologically proven MSI who underwent 18F-FDG PET/CT examination from January 2016 to May 2022. Intratumoral-metabolic heterogeneity (including heterogeneity index [HI] and heterogeneity factor [HF]) and conventional metabolic parameters (standardized uptake value [SUV], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) of the primary lesions were determined. MTV and SUVmean were calculated on the basis of the percentage threshold of SUVs at 30%-70%. TLG, HI, and HF were obtained on the basis of the above corresponding thresholds. MSI was determined by immunohistochemical evaluation. Differences in clinicopathologic and various metabolic parameters between MSI-High (MSI-H) and microsatellite stability (MSS) groups were assessed. Potential risk factors for MSI were assessed by logistic regression analyses and used for construction of the mathematical model. Area under the curve (AUC) were used to evaluate the predictive ability of factors for MSI.

Results

This study included 88 patients with CRC in stages I-III, including 19 (21.6%) patients with MSI-H and 69 (78.4%) patients with MSS. Poor differentiation, mucinous component, and various metabolic parameters including MTV30%, MTV40%, MTV50%, and MTV60%, as well as HI50%, HI60%, HI70%, and HF in the MSI-H group were significantly higher than those in the MSS group (all P < 0.05). In multivariate logistic regression analyses, post-standardized HI60% by Z-score (P = 0.037, OR: 2.107) and mucinous component (P < 0.001, OR:11.394) were independently correlated with MSI. AUC of HI60% and our model of the HI60% + mucinous component was 0.685 and 0.850, respectively (P = 0.019), and the AUC of HI30% in predicting the mucinous component was 0.663.

Conclusions

Intratumoral-metabolic heterogeneity derived from 18F-FDG PET/CT was higher in MSI-H CRC and predicted MSI in stage I-III CRC patients preoperatively. HI60% and mucinous component were independent risk factors for MSI. These findings provide new methods to predict the MSI and mucinous component for patients with CRC.

Altered Glycosylation in Progression and Management of Bladder Cancer

Bladder cancer (BC) is the 10th most common malignancy worldwide, with an estimated 573,000 new cases and 213,000 deaths in 2020. Available therapeutic approaches are still unable to reduce the incidence of BC metastasis and the high mortality rates of BC patients. Therefore, there is a need to deepen our understanding of the molecular mechanisms underlying BC progression to develop new diagnostic and therapeutic tools. One such mechanism is protein glycosylation. Numerous studies reported changes in glycan biosynthesis during neoplastic transformation, resulting in the appearance of the so-called tumor-associated carbohydrate antigens (TACAs) on the cell surface. TACAs affect a wide range of key biological processes, including tumor cell survival and proliferation, invasion and metastasis, induction of chronic inflammation, angiogenesis, immune evasion, and insensitivity to apoptosis. The purpose of this review is to summarize the current information on how altered glycosylation of bladder cancer cells promotes disease progression and to present the potential use of glycans for diagnostic and therapeutic purposes.

Dexamethasone Selectively Inhibits Detachment of Metastatic Thyroid Cancer Cells during Random Positioning

We recently reported that synthetic glucocorticoid dexamethasone (DEX) is able to suppress metastasis-like spheroid formation in a culture of follicular thyroid cancer (FTC)-133 cells cultured under random positioning. We now show that this inhibition was selective for two metastatic thyroid carcinoma cells, FTC-133 and WRO, whereas benign Nthy-ori 3-1 thyrocytes and recurrent ML-1 follicular thyroid cancer cells were not affected by DEX. We then compare Nthy-ori 3-1 and FTC-133 cells concerning their adhesion and mechanosignaling. We demonstrate that DEX disrupts random positioning-triggered p38 stress signaling in FTC-133 cells, thereby antagonizing a variety of biological functions. Thus, DEX treatment of FTC-133 cells is associated with increased adhesiveness, which is mainly caused by the restored, pronounced formation of a normal number of tight junctions. Moreover, we show that Nthy-ori 3-1 and ML-1 cells upregulate the anti-adhesion protein mucin-1 during random positioning, presumably as a protection against mechanical stress. In summary, mechanical stress seems to be an important component in this metastasis model system that is processed differently by metastatic and healthy cells. The balance between adhesion, anti-adhesion and cell–cell connections enables detachment of adherent human cells on the random positioning machine—or not, allowing selective inhibition of thyroid in vitro metastasis by DEX.

Molecular insight of p53/Sp1/MUC5AC axis in the tumorigenesis and progression of lung adenocarcinoma

The aberrant expression of secretory mucin MUC5AC has been documented during the tumourigenesis and progression of various cancers. However, little is currently known on the function of MUC5AC in lung adenocarcinoma. The present study focused on the tumour-promoting role of MUC5AC and its regulatory mechanisms in lung adenocarcinoma. Firstly, MUC5AC expression was evaluated in NSCLC tissue microarrays by immunohistochemistry. Kaplan-Meier analysis were used to clarify the prognostic value of MUC5AC. Subsequently, small interfering RNA and small hairpin RNA were used to knockdown MUC5AC in lung ADC cell lines to elucidate its role in tumorigenesis and progression of lung adenocarcinoma via in vitro functional assays and xenograft mouse models. Finally, the regulatory mechanisms underlying p53/Sp1/MUC5AC axis were identified through dual-luciferase report. We found that MUC5AC was upregulated in lung ADC tissues and cell lines, especially in KRAS-mutant cases and correlated with poor prognosis. MUC5AC gene silencing resulted in reduced cell proliferation, invasion and migration. Furthermore, knockdown of MUC5AC led to reversion of the epithelial-mesenchymal transition. Additionally, downregulation of MUC5AC reduced tumourigenesis in mouse models. Finally, we found an antagonistic role between Sp1 and p53 in the regulation of MUC5AC gene expression. Our findings suggest that high MUC5AC expression promotes tumourigenesis and progression of lung ADC. Both p53 gene inactivation and Sp1 overexpression in lung ADC may enhance MUC5AC expression, especially in KRAS-mutated cases. Given the paucity of efficient drug-targeted approaches of KRAS-driven lung ADCs, therapies directed at downstream effectors such as MUC5AC could have huge prospects.

Tertiary lymphoid structures accompanied by fibrillary matrix morphology impact anti-tumor immunity in basal cell carcinomas

Tertiary lymphoid structures (TLS) are specialized lymphoid formations that serve as local repertoire of T- and B-cells at sites of chronic inflammation, autoimmunity, and cancer. While presence of TLS has been associated with improved response to immune checkpoint blockade therapies and overall outcomes in several cancers, its prognostic value in basal cell carcinoma (BCC) has not been investigated. Herein, we determined the prognostic impact of TLS by relating its prevalence and maturation with outcome measures of anti-tumor immunity, namely tumor infiltrating lymphocytes (TILs) and tumor killing. In 30 distinct BCCs, we show the presence of TLS was significantly enriched in tumors harboring a nodular component and more mature primary TLS was associated with TIL counts. Moreover, assessment of the fibrillary matrix surrounding tumors showed discrete morphologies significantly associated with higher TIL counts, critically accounting for heterogeneity in TIL count distribution within TLS maturation stages. Specifically, increased length of fibers and lacunarity of the matrix with concomitant reduction in density and alignment of fibers were present surrounding tumors displaying high TIL counts. Given the interest in inducing TLS formation as a therapeutic intervention as well as its documented prognostic value, elucidating potential impediments to the ability of TLS in driving anti-tumor immunity within the tumor microenvironment warrants further investigation. These results begin to address and highlight the need to integrate stromal features which may present a hindrance to TLS formation and/or effective function as a mediator of immunotherapy response.

Pump proton inhibitors display anti-tumour potential in glioma

OBJECTIVES

Glioma is one of the most aggressive brain tumours with poor overall survival despite advanced technology in surgical resection, chemotherapy and radiation. Progression and recurrence are the hinge causes of low survival. Our aim is to explain the concrete mechanism in the proliferation and progression of tumours based on tumour microenvironment (TME). The main purpose is to illustrate the mechanism of proton pump inhibitors (PPIs) in affecting acidity, hypoxia, oxidative stress, inflammatory response and autophagy based on the TME to induce apoptosis and enhance the sensitivity of chemoradiotherapy.

FINDINGS

TME is the main medium for tumour growth and progression. Acidity, hypoxia, inflammatory response, autophagy, angiogenesis and so on are the main causes of tumour progress. PPIs, as a common clinical drug to inhibit gastric acid secretion, have the advantages of fast onset, long action time and small adverse reactions. Nowadays, several kinds of literature highlight the potential of PPIs in inhibiting tumour progression. However, long-term use of PPIs alone also has obvious side effects. Therefore, till now, how to apply PPIs to promote the effect of radio-chemotherapy and find the concrete dose and concentration of combined use are novel challenges.

CONCLUSIONS

PPIs display the potential in enhancing the sensitivity of chemoradiotherapy to defend against glioma based on TME. In the clinic, it is also necessary to explore specific concentrations and dosages in synthetic applications.

Mucosomes: Intrinsically Mucoadhesive Glycosylated Mucin Nanoparticles as Multi-Drug Delivery Platform

Mucus is a complex barrier for pharmacological treatments and overcoming it is one of the major challenges faced during transmucosal drug delivery. To tackle this issue, a novel class of glycosylated nanoparticles, named "mucosomes," which are based on the most important protein constituting mucus, the mucin, is introduced. Mucosomes are designed to improve drug absorption and residence time on the mucosal tissues. Mucosomes are produced (150-300 nm), functionalized with glycans, and loaded with the desired drug in a single one-pot synthetic process and, with this method, a wide range of small and macro molecules can be loaded with different physicochemical properties. Various in vitro models are used to test the mucoadhesive properties of mucosomes. The presence of functional glycans is indicated by the interaction with lectins. Mucosomes are proven to be storable at 4 °C after lyophilization, and administration through a nasal spray does not modify the morphology of the mucosomes. In vitro and in vivo tests indicate mucosomes do not induce adverse effects under the investigated conditions. This study proposes mucosomes as a ground-breaking nanosystem that can be applied in several pathological contexts, especially in mucus-related disorders.