Pancreatic ductal adenocarcinoma mice lacking mucin 1 have a profound defect in tumor growth and metastasis

Plasma extracellular vesicles proteomics in meningioma patients

Tumor derived Extracellular vesicles (EVs) in circulating system may contain tumor-specific markers, and EV detection in body fluids could become an important tool for early tumor diagnosis, prognosis assessment. Meningiomas are the most common benign intracranial tumors, few studies have revealed specific protein markers for meningiomas from patients' body fluids. In this study, using proximity labeling technology and non-tumor patient plasma as a control, we detected protein levels of EVs in plasma samples from meningioma patients before and after surgery. Through bioinformatics analysis, we discovered that the levels of EV count and protein count in meningioma patients were significantly higher than those in healthy controls, and were significantly decreased postoperatively. Among EV proteins in meningioma patients, the levels of MUC1, SIGLEC11, E-Cadherin, KIT, and TASCTD2 were found not only significantly elevated than those in healthy controls, but also significantly decreased after tumor resection. Moreover, using publicly available GEO databases, we verified that the mRNA level of MUC1, SIGLEC11, and CDH1 in meningiomas were significantly higher in comparison with normal dura mater tissues. Additionally, by analyzing human meningioma specimens collected in this study, we validated the protein levels of MUC1 and SIGLEC11 were significantly increased in WHO grade 2 meningiomas and were positively correlated with tumor proliferation levels. This study indicates that meningiomas secret EV proteins into circulating system, which may serve as specific markers for diagnosis, malignancy predicting and tumor recurrent assessment.

Mucin-1-Targeted Chimeric Antigen Receptor T Cells Are Effective and Safe in Controlling Solid Tumors in Immunocompetent Host

The chimeric antigen receptor (CAR) T-cell therapy in solid epithelial tumors has been explored, however, with limited success. As much of the preclinical work has relied on xenograft models in immunocompromised animals, the immune-related efficacies and toxicities may have been missed. In this study, we engineered syngeneic murine CAR T cells targeting the tumor form of human mucin-1 (tMUC1) and tested the MUC1 CAR T cells' efficacy and toxicity in the immunocompetent human MUC1-expressing mouse models. The MUC1 CAR T cells significantly eliminated murine pancreatic and breast cancer cell lines in vitro. In vivo, MUC1 CAR T cells significantly slowed the mammary gland tumor progression in the spontaneous PyVMT×MUC1.Tg (MMT) mice, prevented lung metastasis, and prolonged survival. Most importantly, there was minimal short or long-term toxicity with acceptable levels of transient liver toxicity but no kidney toxicity. In addition, the mice did not show any signs of weight loss or other behavioral changes with the treatment. We also report that a single dose of MUC1 CAR T-cell treatment modestly reduced the pancreatic tumor burden in a syngeneic orthotopic model of pancreatic ductal adenocarcinoma given at late stage of an established tumor. Taken together, these findings suggested the further development of tMUC1-targeted CAR T cells as an effective and relatively safe treatment modality for various tMUC1-expressing solid tumors.

Validation of dual energy X-ray absorptiometry for longitudinal quantification of tumor burden in a murine model of pancreatic ductal adenocarcinoma

Noninvasive imaging is central to preclinical, in vivo models of pancreatic ductal adenocarcinoma (PDAC). While bioluminescent imaging (BLI) is a gold standard, its signal is dependent on the metabolic activity of tumor cells. In contrast, dual energy X-ray absorptiometry (DEXA) is a direct measure of body composition. Thus, we aimed to assess its potential for longitudinal quantification of tumor burden versus BLI. We utilized the KCKO murine model of PDAC and subjected tumor-bearing (n = 20) and non-tumor control (NTC) (n = 10) animals to weekly BLI and DEXA measurements for up to 10 weeks. While BLI detected tumors at 1-week, it failed to detect tumor growth, displayed a decreasing trend overtime (slope = -9.0x108; p = 0.0028), and terminal signal did not correlate with ex vivo tumor mass (r = 0.01853; p = 0.6286). In contrast, DEXA did not detect elevated changes in abdominal cavity lean mass until week 2 post inoculation and tumors were not visible until week 3, but successfully quantified a tumor growth trend (slope = 0.7322; p<0.0001), and strongly correlated with final tumor mass (r = 0.9351; p<0.0001). These findings support the use of BLI for initial tumor engraftment and persistence but demonstrate the superiority of DEXA for longitudinal tumor burden studies. As tumor detection by DEXA is not restricted to luciferase expressing models, future studies to assess its value in various cancer models and as an in vivo outcome measure of treatment efficacy are warranted.

Advances in MUC1 resistance to chemotherapy in pancreatic cancer

The incidence of pancreatic cancer (PC), a highly fatal malignancy, is increasing every year. Chemotherapy is an important treatment for it in addition to surgery, yet most patients become resistant to chemotherapeutic agents within a few weeks of treatment initiation.​ MUC1 is a highly glycosylated transmembrane protein, and studies have shown that aberrantly glycosylated overexpression of MUC1 is involved in regulating the biology of chemoresistance in cancer cells. This article summarizes the mechanism of MUC1 in PC chemoresistance and reviews MUC1-based targeted therapies.

Developments and challenges in neoadjuvant therapy for locally advanced pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a significant public health challenge and is currently the fourth leading cause of cancer-related mortality in developed countries. Despite advances in cancer treatment, the 5-year survival rate for patients with PDAC remains less than 5%. In recent years, neoadjuvant therapy (NAT) has emerged as a promising treatment option for many cancer types, including locally advanced PDAC, with the potential to improve patient outcomes. To analyze the role of NAT in the setting of locally advanced PDAC over the past decade, a systematic literature search was conducted using PubMed and Web of Science. The results suggest that NAT may reduce the local mass size, promote tumor downstaging, and increase the likelihood of resection. These findings are supported by the latest evidence-based medical literature and the clinical experience of our center. Despite the potential benefits of NAT, there are still challenges that need to be addressed. One such challenge is the lack of consensus on the optimal timing and duration of NAT. Improved criteria for patient selection are needed to further identify PDAC patients likely to respond to NAT. In conclusion, NAT has emerged as a promising treatment option for locally advanced PDAC. However, further research is needed to optimize its use and to better understand the role of NAT in the management of this challenging disease. With continued advances in cancer treatment, there is hope of improving the outcomes of patients with PDAC in the future.

Structural and molecular insight into antibody recognition of dynamic neoepitopes in membrane tethered MUC1 of pancreatic cancer cells and secreted exosomes

Pancreatic cancer is highly metastatic and has poor prognosis, mainly due to delayed detection, often after metastasis has occurred. A novel method to enable early detection and disease intervention is strongly needed. Here we unveil for the first time that pancreatic cancer cells (PANC-1) and secreted exosomes express MUC1 bearing cancer-relevant dynamic epitopes recognized specifically by an anti-MUC1 antibody (SN-131), which binds specifically core 1 but not core 2 type O-glycans found in normal cells. Comprehensive assessment of the essential epitope for SN-131 indicates that PANC-1 cells produce dominantly MUC1 with aberrant O-glycoforms such as Tn, T, and sialyl T (ST) antigens. Importantly, SN-131 showed the highest affinity with MUC1 bearing ST antigen at the immunodominant DTR motif (KD = 1.58 nM) independent of the glycosylation states of other Ser/Thr residues in the MUC1 tandem repeats. The X-ray structure revealed that SN-131 interacts directly with Neu5Ac and root GalNAc of the ST antigen in addition to the proximal peptide region. Our results demonstrate that targeting O-glycosylated "dynamic neoepitopes" found in the membrane-tethered MUC1 is a promising therapeutic strategy for improving the treatment outcome of patients with pancreatic cancer.

Suppression of MUC1-Overexpressing Tumors by a Novel MUC1/CD3 Bispecific Antibody

Mucin1 (MUC1) is abnormally glycosylated and overexpressed in a variety of epithelial cancers and plays a critical role in tumor progression. MUC1 has received remark attention as an oncogenic molecule and is considered a valuable tumor target for immunotherapy, while many monoclonal antibodies (mAbs) targeting MUC1-positive cancers in clinical studies lack satisfactory results. It would be highly desirable to develop an effective therapy against MUC1-expressing cancers. In this study, we constructed a novel T cell-engaging bispecific antibody (BsAb) targeting MUC1 and CD3 with the Fab-ScFv-IgG format. A high quality of MUC1-CD3 BsAb can be acquired through a standard method. Our study suggested that this BsAb could specifically bind to MUC1- and CD3-positive cells and efficiently enhance T cell activation, cytokine release, and cytotoxicity. Furthermore, our study demonstrated that this BsAb could potently redirect T cells to eliminate MUC1-expressing tumor cells in vitro and significantly suppress MUC1-positive tumor growth in a xenograft mouse model. Thus, T cell-engaging MUC1/CD3 BsAb could be an effective therapeutic approach to combat MUC1-positive tumors and our MUC1/CD3 BsAb could be a promising candidate in clinical applications for the treatment of MUC1-positive cancer patients.

Activation of Vitamin D/VDR Signaling Reverses Gemcitabine Resistance of Pancreatic Cancer Cells Through Inhibition of MUC1 Expression

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) has a poor prognosis due to its therapeutic resistance. Inactivation of vitamin D/vitamin D receptor (VDR) signaling may contribute to the malignant phenotype of PDA and altered expression of oncoprotein mucin 1 (MUC1) may be involved in drug resistance of cancer cells.

AIM

To determine whether vitamin D/VDR signaling regulates the expression and function of MUC1 and its effect on acquired gemcitabine resistance of pancreatic cancer cells.

METHODS

Molecular analyses and animal models were used to determine the impact of vitamin D/VDR signaling on MUC1 expression and response to gemcitabine treatment.

RESULTS

RPPA analysis indicated that MUC1 protein expression was significantly reduced in human PDA cells after treatment with vitamin D3 or its analog calcipotriol. VDR regulated MUC1 expression in both gain- and loss-of-function assays. Vitamin D3 or calcipotriol significantly induced VDR and inhibited MUC1 expression in acquired gemcitabine-resistant PDA cells and sensitized the resistant cells to gemcitabine treatment, while siRNA inhibition of MUC1 was associated with paricalcitol-associated sensitization of PDA cells to gemcitabine treatment in vitro. Administration of paricalcitol significantly enhanced the therapeutic efficacy of gemcitabine in xenograft and orthotopic mouse models and increased the intratumoral concentration of dFdCTP, the active metabolite of gemcitabine.

CONCLUSION

These findings demonstrate a previously unidentified vitamin D/VDR-MUC1 signaling axis involved in the regulation of gemcitabine resistance in PDA and suggests that combinational therapies that include targeted activation of vitamin D/VDR signaling may improve the outcomes of patients with PDA.

Altered glycosylation in pancreatic cancer and beyond

Pancreatic ductal adenocarcinoma (PDA) is one of the deadliest cancers and is projected to soon be the second leading cause of cancer death. Median survival of PDA patients is 6-10 mo, with the majority of diagnoses occurring at later, metastatic stages that are refractory to treatment and accompanied by worsening prognoses. Glycosylation is one of the most common types of post-translational modifications. The complex landscape of glycosylation produces an extensive repertoire of glycan moieties, glycoproteins, and glycolipids, thus adding a dynamic and tunable level of intra- and intercellular signaling regulation. Aberrant glycosylation is a feature of cancer progression and influences a broad range of signaling pathways to promote disease onset and progression. However, despite being so common, the functional consequences of altered glycosylation and their potential as therapeutic targets remain poorly understood and vastly understudied in the context of PDA. In this review, the functionality of glycans as they contribute to hallmarks of PDA are highlighted as active regulators of disease onset, tumor progression, metastatic capability, therapeutic resistance, and remodeling of the tumor immune microenvironment. A deeper understanding of the functional consequences of altered glycosylation will facilitate future hypothesis-driven studies and identify novel therapeutic strategies in PDA.

Overexpression of MUC1 Induces Non-Canonical TGF-β Signaling in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human cancers. Transforming Growth Factor Beta (TGF-β) is a cytokine that switches from a tumor-suppressor at early stages to a tumor promoter in the late stages of tumor development, by yet unknown mechanisms. Tumor associated MUC1 is aberrantly glycosylated and overexpressed in >80% of PDAs and is associated with poor prognosis. MUC1 expression is found in the early stages of PDA development with subsequent increase in later stages. Analysis of human PDA samples from TCGA database showed significant differences in gene expression and survival profiles between low and high MUC1 samples. Further, high MUC1 expression was found to positively correlate to TGF-βRII expression and negatively correlate to TGF-βRI expression in PDA cell lines. We hypothesized that MUC1 overexpression induces TGF-β mediated non-canonical signaling pathways which is known to be associated with poor prognosis. In this study, we report that MUC1 overexpression in PDA cells directly activates the JNK pathway in response to TGF-β, and leads to increased cell viability via up-regulation and stabilization of c-Myc. Conversely, in low MUC1 expressing PDA cells, TGF-β preserves its tumor-suppressive function and inhibits phosphorylation of JNK and stabilization of c-Myc. Knockdown of MUC1 in PDA cells also results in decreased phosphorylation of JNK and c-Myc in response to TGF-β treatment. Taken together, the results indicate that overexpression of MUC1 plays a significant role in switching the TGF-β function from a tumor-suppressor to a tumor promoter by directly activating JNK. Lastly, we report that high-MUC1 PDA tumors respond to TGF-β neutralizing antibody in vivo showing significantly reduced tumor growth while low-MUC1 tumors do not respond to TGF-β neutralizing antibody further confirming our hypothesis.

Advanced Nanoengineering Approach for Target-Specific, Spatiotemporal, and Ratiometric Delivery of Gemcitabine-Cisplatin Combination for Improved Therapeutic Outcome in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an intractable malignancy with a dismal survival rate. Recent combination therapies have had a major impact on the improvement of PDAC prognosis. Nevertheless, clinically used combination regimens such as FOLFIRINOX and gemcitabine (Gem)/nab-paclitaxel still face major challenges due to lack of the safe and ratiometric delivery of multiple drugs. Here, a rationally designed mesoporous silica nanoparticle (MSN)-based platform is reported for the target-specific, spatiotemporal, ratiometric, and safe co-delivery of Gem and cisplatin (cisPt). It is shown that systemic administration of the nanoparticles results in synergistic therapeutic outcome in a syngeneic and clinically relevant genetically engineered PDAC mouse model that has rarely been used for the therapeutic evaluation of nanomedicine. This synergism is associated with a strategic engineering approach, in which nanoparticles provide redox-responsive controlled delivery and in situ differential release of Gem/cisPt drugs with the goal of overcoming resistance to Pt-based drugs. The platform is also rendered with additional tumor-specificity via a novel tumor-associated mucin1 (tMUC1)-specific antibody, TAB004. Overall, the platform suppresses tumor growth and eliminates the off-target toxicities of a highly toxic chemotherapy combination.

Spatial transcriptomics at subspot resolution with BayesSpace

Recent spatial gene expression technologies enable comprehensive measurement of transcriptomic profiles while retaining spatial context. However, existing analysis methods do not address the limited resolution of the technology or use the spatial information efficiently. Here, we introduce BayesSpace, a fully Bayesian statistical method that uses the information from spatial neighborhoods for resolution enhancement of spatial transcriptomic data and for clustering analysis. We benchmark BayesSpace against current methods for spatial and non-spatial clustering and show that it improves identification of distinct intra-tissue transcriptional profiles from samples of the brain, melanoma, invasive ductal carcinoma and ovarian adenocarcinoma. Using immunohistochemistry and an in silico dataset constructed from scRNA-seq data, we show that BayesSpace resolves tissue structure that is not detectable at the original resolution and identifies transcriptional heterogeneity inaccessible to histological analysis. Our results illustrate BayesSpace's utility in facilitating the discovery of biological insights from spatial transcriptomic datasets.

Recent Advances on Functional Nucleic-Acid Biosensors

In the past few decades, biosensors have been gradually developed for the rapid detection and monitoring of human diseases. Recently, functional nucleic-acid (FNA) biosensors have attracted the attention of scholars due to a series of advantages such as high stability and strong specificity, as well as the significant progress they have made in terms of biomedical applications. However, there are few reports that systematically and comprehensively summarize its working principles, classification and application. In this review, we primarily introduce functional modes of biosensors that combine functional nucleic acids with different signal output modes. In addition, the mechanisms of action of several media of the FNA biosensor are introduced. Finally, the practical application and existing problems of FNA sensors are discussed, and the future development directions and application prospects of functional nucleic acid sensors are prospected.

MUC1: Structure, Function, and Clinic Application in Epithelial Cancers

The transmembrane glycoprotein mucin 1 (MUC1) is a mucin family member that has different functions in normal and cancer cells. Owing to its structural and biochemical properties, MUC1 can act as a lubricant, moisturizer, and physical barrier in normal cells. However, in cancer cells, MUC1 often undergoes aberrant glycosylation and overexpression. It is involved in cancer invasion, metastasis, angiogenesis, and apoptosis by virtue of its participation in intracellular signaling processes and the regulation of related biomolecules. This review introduces the biological structure and different roles of MUC1 in normal and cancer cells and the regulatory mechanisms governing these roles. It also evaluates current research progress and the clinical applications of MUC1 in cancer therapy based on its characteristics.

Increased myocellular lipid and IGFBP-3 expression in a pre-clinical model of pancreatic cancer-related skeletal muscle wasting

BACKGROUND

Skeletal muscle wasting (SMW) in cancer patients is associated with increased morbidity, mortality, treatment intolerance and discontinuation, and poor quality of life. This is particularly true for patients with pancreatic ductal adenocarcinoma (PDAC), as over 85% experience SMW, which is responsible for ~30% of patient deaths. While the established paradigm to explain SMW posits that muscle catabolism from systemic inflammation and nutritional deficiencies, the cause of death, and the cellular and molecular mechanisms responsible remain to be elucidated. To address this, we investigated the relationship between tumour burden and survival in the KCKO murine PDAC model.

METHODS

Female C57BL/6J mice 6-8 weeks of age underwent orthotopic injection with KCKO-luc tumour cells. Solid tumour was verified on Day 5, post-tumour inoculation. In vivo, longitudinal lean mass and tumour burden were assessed via dual-energy X-ray absorptiometry and IVIS imaging, respectively, and total body weight was assessed, weekly. Animals were sacrificed at a designated end point of 'failure to thrive'. After sacrifice, lower limb hind muscles were harvested for histology and RNA extraction.

RESULTS

We found a strong correlation between primary tumour size and survival (r2  = 0.83, P < 0.0001). A significant decrease in lower limb lean mass was first detected at Day 38 post-implantation vs. no tumour controls (NTCs) (P < 0.0001). SMW was confirmed by histology, which demonstrated a 38%, 32.7%, and 39.9% decrease in fibre size of extensor digitorum longus, soleus, and tibialis anterior muscles, respectively, in PDAC mice vs. NTC (P < 0.002). Histology also revealed a 67.6% increase in haematopoietic cells within the muscle of PDAC mice when compared with NTC. Bulk RNAseq on muscles from PDAC mice vs. NTC revealed significant increases in c/ebpβ/Δ, il-1, il-6, and tnf gene expression. Pathway analyses to identify potential upstream factors revealed increased adipogenic gene expression, including a four-fold increase in igfbp-3. Histomorphometry of Oil Red-O staining for fat content in tibialis anterior muscles demonstrated a 95.5% increase in positively stained fibres from PDAC mice vs. NTC.

CONCLUSIONS

Together, these findings support a novel model of PDAC-associated SMW and mortality in which systemic inflammation leads to inflammatory cell infiltration into skeletal muscle with up-regulated myocellular lipids.

Repression of MUC1 Promotes Expansion and Suppressive Function of Myeloid-Derived Suppressor Cells in Pancreatic and Breast Cancer Murine Models

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that are responsible for immunosuppression in tumor microenvironment. Here we report the impact of mucin 1 (MUC1), a transmembrane glycoprotein, on proliferation and functional activity of MDSCs. To determine the role of MUC1 in MDSC phenotype, we analyzed MDSCs derived from wild type (WT) and MUC1-knockout (MUC1KO) mice bearing syngeneic pancreatic (KCKO) or breast (C57MG) tumors. We observed enhanced tumor growth of pancreatic and breast tumors in the MUC1KO mice compared to the WT mice. Enhanced tumor growth in the MUC1KO mice was associated with increased numbers of suppressive MDSCs and T regulatory (Tregs) cells in the tumor microenvironment. Compared to the WT host, MUC1KO host showed higher levels of iNOS, ARG1, and TGF-β, thus promoting proliferation of MDSCs with an immature and immune suppressive phenotype. When co-cultured with effector T cells, MDSCs from MUC1KO mice led to higher repression of IL-2 and IFN-γ production by T cells as compared to MDSCs from WT mice. Lastly, MDSCs from MUC1KO mice showed higher levels of c-Myc and activated pSTAT3 as compared to MDSCs from WT mice, suggesting increased survival, proliferation, and prevention of maturation of MDSCs in the MUC1KO host. We report diminished T cell function in the KO versus WT mice. In summary, the data suggest that MUC1 may regulate signaling pathways that are critical to maintain the immunosuppressive properties of MDSCs.

DNA branch migration amplification cascades for enzyme-free and non-label aptamer sensing of mucin 1

The sensitive and quantitative analysis of mucin 1 (MUC1) is very important for the prevention and early diagnosis of cancers. In the present work, based on the mechanism of the four-way DNA branch migration cascades, we constructed a simple and effective signal amplification strategy for aptamer-based sensitive detection of MUC1. The specific binding of MUC1 to the aptamer sequence in the hairpin probe unfolds and switches its structure, triggering the formation of the DNA Holliday junction structure for cascaded branch migrations with the assistance of two fuel DNA duplexes. Importantly, a target analogue DNA complex can be generated in such processes for recycling the branch migration reactions for the production of substantial amounts of G-quadruplexes, which can bind the thioflavin T dye to show significantly intensified fluorescence for detecting MUC1 with a low detection limit of 2.8 nM without the involvement of any labels or enzymes. In addition, this detection strategy could be successfully applied to monitor the target MUC1 in diluted human serums with a high selectivity and acceptable accuracy to demonstrate its potential application for real samples with the advantages of simplicity and signal amplification capability.

Crosstalk between MUC1 and VEGF in angiogenesis and metastasis: a review highlighting roles of the MUC1 with an emphasis on metastatic and angiogenic signaling

VEGF and its receptor family (VEGFR) members have unique signaling transduction system that play significant roles in most pathological processes, such as angiogenesis in tumor growth and metastasis. VEGF-VEGFR complex is a highly specific mitogen for endothelial cells and any de-regulation of the angiogenic balance implicates directly in endothelial cell proliferation and migration. Moreover, it has been shown that overexpressing Mucin 1 (MUC1) on the surface of many tumor cells resulting in upregulation of numerous signaling transduction cascades, such as growth and survival signaling pathways related to RTKs, loss of cell-cell and cell-matrix adhesion, and EMT. It promotes gene transcription of pro-angiogenic proteins such as HIF-1α during periods of oxygen scarcity (hypoxia) to enhance tumor growth and angiogenesis stimulation. In contrast, the cytoplasmic domain of MUC1 (MUC1-C) inhibits apoptosis, which in turn, impresses upon cell fate. Besides, it has been established that reduction in VEGF expression level correlated with silencing MUC1-C level indicating the anti-angiogenic effect of MUC1 downregulation. This review enumerates the role of MUC1-C oncoprotein and VEGF in angiogenesis and metastasis and describes several signaling pathways by which MUC1-C would mediate the pro-angiogenic activities of cancer cells.

Overexpression of Mucin 1 Suppresses the Therapeutical Efficacy of Disulfiram against Canine Mammary Tumor

Simple Summary

Canine mammary tumor is one of the most prevalent canine tumor types in China. Clinical studies showed that the high expression of mucin 1 (MUC1) protein is significantly associated with the malignancy and poor prognosis of canine mammary tumor. Therefore, it is worthwhile to investigate the expression of mucin 1 in developing treatments against canine mammary tumors. In the present study, it is demonstrated that disulfiram, an approved medication in treating human alcoholism, also has inhibitory effects on the growth of canine mammary tumor cells both in vitro and in vivo. With the overexpression of MUC1, the inhibitory effects of disulfiram decrease accordingly. Moreover, disulfiram is shown to inhibit phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase (Akt) signaling transduction, which is attenuated by MUC1 overexpression. Overall, these results indicate that the expression level of MUC1 is detrimental to determining the anti-tumor activity of disulfiram. Further consideration should be given when treating the canine mammary tumor with disulfiram or other PI3K/Akt inhibitors.

Abstract

Mucin 1 (MUC1), a transmembrane protein, is closely associated with the malignancy and metastasis of canine mammary tumors; however, the role of overexpressed MUC1 in the development of cancer cells and response to drug treatment remains unclear. To address this question, we developed a new canine mammary tumor cell line, CIPp-MUC1, with an elevated expression level of MUC1. In vitro studies showed that CIPp-MUC1 cells are superior in proliferation and migration than wild-type control, which was associated with the upregulation of PI3K, p-Akt, mTOR, Bcl-2. In addition, overexpression of MUC1 in CIPp-MUC1 cells inhibited the suppressing activity of disulfiram on the growth and metastasis of tumor cells, as well as inhibiting the pro-apoptotic effect of disulfiram. In vivo studies, on the other side, showed more rapid tumor growth and stronger resistance to disulfiram treatment in CIPp-MUC1 xenograft mice than in wild-type control. In conclusion, our study demonstrated the importance of MUC1 in affecting the therapeutical efficiency of disulfiram against canine mammary tumors, indicating that the expression level of MUC1 should be considered for clinical use of disulfiram or other drugs targeting PI3K/Akt pathway.

Riproximin Exhibits Diversity in Sugar Binding, and Modulates some Metastasis-Related Proteins with Lectin like Properties in Pancreatic Ductal Adenocarcinoma

Riproximin (Rpx) is a type II ribosome-inactivating protein with specific anti-proliferative activity. It was purified from Ximenia americana by affinity chromatography using a resin coupled with lactosyl residues. The same technique facilitated isolation of proteins with lectin-like properties from human Suit2-007 and rat ASML pancreatic cancer cells, which were termed lactosyl-sepharose binding proteins (LSBPs). The role of these proteins in cancer progression was investigated at mRNA level using chip array data of Suit2-007 and ASML cells re-isolated from nude rats. These data compared significant mRNA expression changes when relating primary (pancreas) and metastatic (liver) sites following orthotopic and intraportal implantation of Pancreatic Ductal Adenocarcinoma (PDAC) cells, respectively. The affinity of Rpx to 13 simple sugar structures was modeled by docking experiments, the ranking of which was principally confirmed by NMR-spectroscopy. In addition, Rpx and LSBPs were evaluated for anti-proliferative activity and their cellular uptake was assessed by fluorescence microscopy. From 13 monosaccharides evaluated, open-chain rhamnose, β-d-galactose, and α-l-galactopyranose showed the highest affinities for site 1 of Rpx’s B-chain. NMR evaluation yielded a similar ranking, as galactose was among the best binders. Both, Rpx and LSBPs reduced cell proliferation in vitro, but their anti-proliferative effects were decreased by 15–20% in the presence of galactose. The program “Ingenuity Pathway Analysis” identified 2,415 genes showing significantly modulated mRNA expression following exposure of Suit2-007 cells to Rpx in vitro. These genes were then matched to those 1,639 genes, which were significantly modulated in the rat model when comparing primary and metastatic growth of Suit2-007 cells. In this overlap analysis, LSBP genes were considered separately. The potential suitability of Rpx for treating metastatic Suit2-007 PDAC cells was reflected by those genes, which were modulated by Rpx in a way opposite to that observed in cancer progression. Remarkably, these were 14% of all genes modulated during cancer progression, but 71% of the respective LSBP gene subgroup. Based on these findings, we predict that Rpx has the potential to treat PDAC metastasis by modulating genes involved in metastatic progression, especially by targeting LSBPs.

Mucins in pancreatic cancer: A well-established but promising family for diagnosis, prognosis and therapy

Mucins are a family of multifunctional glycoproteins that mostly line the surface of epithelial cells in the gastrointestinal tract and exert pivotal roles in gut lubrication and protection. Pancreatic cancer is a lethal disease with poor early diagnosis, limited therapeutic effects, and high numbers of cancer‐related deaths. In this review, we introduce the expression profiles of mucins in the normal pancreas, pancreatic precursor neoplasia and pancreatic cancer. Mucins in the pancreas contribute to biological processes such as the protection, lubrication and moisturization of epithelial tissues. They also participate in the carcinogenesis of pancreatic cancer and are used as diagnostic biomarkers and therapeutic targets. Herein, we discuss the important roles of mucins that lead to the lethality of pancreatic adenocarcinoma, particularly MUC1, MUC4, MUC5AC and MUC16 in disease progression, and present a comprehensive analysis of the clinical application of mucins and their promising roles in cancer treatment to gain a better understanding of the role of mucins in pancreatic cancer.

Dual Energy X-ray Absorptiometry (DEXA) as a longitudinal outcome measure of cancer-related muscle wasting in mice

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is notorious for its associated skeletal muscle wasting (SMW) and mortality. Currently, the relationships between PDAC, SMW, and survival are poorly understood. Thus, there is great need for a faithful small animal model with quantitative longitudinal outcome measures that recapitulate clinical PDAC, to define SMW onset and assess progression. Therefore, we aimed to validate dual energy X-ray absorptiometry (DEXA) as a longitudinal measure of lean mass, and demonstrate its utility to quantify SMW in the KCKO murine model of PDAC.

Methods

In vivo body composition of: 1) untreated mice at 5, 8, 12, 18, and 22 weeks of age (n = 4) and 2) a cohort of mice with (n = 5) and without PDAC (n = 5), was determined via DEXA and lean mass of the lower hind limbs was predicted via a region of interest analysis by two-independent observers. Total body weight was determined. Tibialis anterior (TA) muscles were weighed and processed for histomorphometry immediately post-mortem. Statistical differences between groups were assessed using ANOVA and Student’s t-tests. Linear regression models and correlation analysis were used to measure the association between TA and DEXA mass, and reproducibility of DEXA was quantified via the intraclass correlation coefficient (ICC).

Results

Lean mass in growing untreated mice determined by DEXA correlated with TA mass (r² = 0.94; p <0.0001) and body weight (r² = 0.89; p <0.0001). DEXA measurements were highly reproducible between observers (ICC = 0.95; 95% CI: 0.89–0.98). DEXA and TA mass also correlated in the PDAC cohort (r² = 0.76; p <0.0001). Significant SMW in tumor-bearing mice was detected within 38 days of implantation, by DEXA, TA mass, and histomorphometry.

Conclusions

DEXA is a longitudinal outcome measure of lean mass in mice. The KCKO syngeneic model is a bona fide model of PDAC associated SMW that can be quantified with longitudinal DEXA.

MUC1 promotes glycolysis through inhibiting BRCA1 expression in pancreatic cancer

Enhanced glucose metabolism is one of the hallmarks of pancreatic cancer. MUC1, a transmembrane protein, is a global regulator of glucose metabolism and essential for progression of pancreatic cancer. To clarify the role of MUC1 in glucose metabolism, we knocked out MUC1 in Capan-1 and CFPAC-1 cells. MUC1 knockout (KO) cells uptook less glucose and secreted less lactate with a much lower proliferating rate. The mRNA level of key enzymes in glycolysis also decreased significantly in MUC1 KO cells. We also observed increased expression of breast cancer type 1 susceptibility protein (BRCA1) in MUC1 KO cells. Since BRCA1 has a strong inhibitory effect on glycolysis, we want to know whether the decreased glucose metabolism in MUC1 KO cells is due to increased BRCA1 expression. We treated wild type (WT) and MUC1 KO cells with BRCA1 inhibitor. BRCA1 inhibition significantly enhanced glucose uptake and lactate secretion in both WT and MUC1 KO cells. Expression of key enzymes in glycolysis also elevated after BRCA1 inhibition. Elevated glucose metabolism is known to facilitate cancer cells to gain chemoresistance. We treated MUC1 KO cells with gemcitabine and FOLFIRINOX in vitro and in vivo. The results showed that MUC1 KO sensitized pancreatic cancer cells to chemotherapy both in vitro and in vivo. In conclusion, we demonstrated that MUC1 promotes glycolysis through inhibiting BRCA1 expression. MUC1 may be a therapeutic target in pancreatic cancer treatment.

Shear Wave Elastography Can Differentiate between Radiation-Responsive and Non-responsive Pancreatic Tumors: An ex Vivo Study with Murine Models

Neither contrast-enhanced computed tomography nor magnetic resonance imaging can monitor changes in the pancreatic ductal adenocarcinoma microenvironment during therapy. We hypothesized that shear wave elastography could overcome this limitation. To test this hypothesis, we measured the shear modulus of two groups of murine pancreatic tumors (KCKO, n = 30; PAN02, n = 30) treated with stereotactic body radiation therapy (SBRT). The mean shear modulus of KCKO tumors was 7.651 kPa higher than that of PAN02 tumors (p < 0.001). SBRT reduced the shear modulus in KCKO tumors by 8.914 kPa (p < 0.001). No significant difference in the shear modulus of SBRT-treated PAN02 tumors was observed. Additionally, necrotic and collagen densities were reduced only in the SBRT-treated KCKO tumors. Shear modulus was dependent on collagen distribution and histological texture parameters (i.e., entropy and fractional dimension). Shear wave elastography imaging differentiates between SBRT-responsive (KCKO) and non-responsive (PAN02) tumors.

Assessing the Magnitude of Immunogenic Cell Death Following Chemotherapy and Irradiation Reveals a New Strategy to Treat Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) continues to have a dismal prognosis, in part, due to ineffective treatment strategies. The efficacy of some chemotherapies and especially radiotherapy is mediated partially by the immune system. Therefore, we hypothesized that profiling the immune response following chemotherapy and/or irradiation can be used as a readout for treatment efficacy but also to help identify optimal therapeutic schedules for PDAC. Using murine models of PDAC, we demonstrated that concurrent administration of stereotactic body radiotherapy (SBRT) and a modified dose of FOLFIRINOX (mFX) resulted in superior tumor control when compared with single or sequential treatment groups. Importantly, this combined treatment schedule enhanced the magnitude of immunogenic cell death, which in turn amplified tumor antigen presentation by dendritic cells and intratumoral CD8+ T-cell infiltration. Concurrent therapy also resulted in systemic immunity contributing to the control of established metastases. These findings provide a rationale for pursuing concurrent treatment schedules of SBRT with mFX in PDAC.

Membrane-associated mucins of the ocular surface: New genes, new protein functions and new biological roles in human and mouse

The mucosal glycocalyx of the ocular surface constitutes the point of interaction between the tear film and the apical epithelial cells. Membrane-associated mucins (MAMs) are the defining molecules of the glycocalyx in all mucosal epithelia. Long recognized for their biophysical properties of hydration, lubrication, anti-adhesion and repulsion, MAMs maintain the wet ocular surface, lubricate the blink, stabilize the tear film and create a physical barrier to the outside world. However, it is increasingly appreciated that MAMs also function as cell surface receptors that transduce information from the outside to the inside of the cell. A number of excellent review articles have provided perspective on the field as it has progressed since 1987, when molecular cloning of the first MAM was reported. The current article provides an update for the ocular surface, placing it into the broad context of findings made in other organ systems, and including new genes, new protein functions and new biological roles. We discuss the epithelial tissue-equivalent with mucosal differentiation, the key model system making these advances possible. In addition, we make the first systematic comparison of MAMs in human and mouse, establishing the basis for using knockout mice for investigations with the complexity of an in vivo system. Lastly, we discuss findings from human genetics/genomics, which are providing clues to new MAM roles previously unimagined. Taken together, this information allows us to generate hypotheses for the next stage of investigation to expand our knowledge of MAM function in intracellular signaling and roles unique to the ocular surface.

Experimental pancreatic cancer develops in soft pancreas: novel leads for an individualized diagnosis by ultrafast elasticity imaging

Rapid, easy and early pancreatic cancer diagnosis and therapeutic follow up continue to necessitate an increasing attention towards the development of effective treatment strategies for this lethal disease. The non invasive quantitative assessment of pancreatic heterogeneity is limited. Here, we report the development of a preclinical imaging protocol using ultrasonography and shear wave technology in an experimental in situ pancreatic cancer model to measure the evolution of pancreatic rigidity.

Methods: Intrapancreatic tumors were genetically induced by mutated Kras and p53 in KPC mice. We evaluated the feasiblity of a live imaging protocol by assessing pancreas evolution with Aixplorer technology accross 36 weeks. Lethality induced by in situ pancreatic cancer was heterogeneous in time.

Results: The developed method successfully detected tumor mass from 26 weeks onwards at minimal 0.029 cm³ size. Elastography measurements using shear wave methodology had a wide detection range from 4.7kPa to 166.1kPa. Protumorigenic mutations induced a significant decrease of the rigidity of pancreatic tissue before tumors developed in correlation with the detection of senescent marker p16-positive cells. An intratumoral increased rigidity was quantified and found surprisingly heterogeneous. Tumors also presented a huge inter-individual heterogeneity in their rigidity parameters; tumors with low and high rigidity at detection evolve very heterogeneously in their rigidity parameters, as well as in their volume. Increase in rigidity in tumors detected by ultrafast elasticity imaging coincided with detection of tumors by echography and with the detection of the inflammatory protumoral systemic condition by non invasive follow-up and of collagen fibers by post-processing tumoral IHC analysis.

Conclusion: Our promising results indicate the potential of the shear wave elastography to support individualization of diagnosis in this most aggressive disease.

Aptamer-tagged silver nanoclusters for cell image and Mucin1 detection in vitro

Development of specific cell imaging technology for accurate tumor early diagnosis and evaluation of drug therapeutic efficiency is in great demand. In this study, a simple and sensitive fluorescence method for Mucin1 (MUC1) image in situ and quantitative assay in vitro has been established using APT-tagged silver nanoclusters (APT-Agnes) containing a recognition unit of MUC1 aptamer as the label-free fluorescence probe. The principle of the method is that specific recognition and binding of MUC1 with aptamer can result in the fluorescence quenching of APT-Agnes. The method for MUC1 assay showed a linear range from 0.1 to 100 NM with a limit of detection of 0.05 nM. Furthermore, the fluorescent probe of APT-AgNCs was successfully used for detection of MUC1 in serum and MCF-7 cell imaging. In our point, the above results demonstrated that the new simple method provided an alternative for direct quantitative assay of MUC1 in homogeneous solution and cell imaging, which is helpful for biomedical study and clinical diagnosis related with MUC1.

Combining the Specific Anti-MUC1 Antibody TAB004 and Lip-MSA-IL-2 Limits Pancreatic Cancer Progression in Immune Competent Murine Models of Pancreatic Ductal Adenocarcinoma

Immunotherapy regimens have shown success in subsets of cancer patients; however, their efficacy against pancreatic ductal adenocarcinoma (PDA) remain unclear. Previously, we demonstrated the potential of TAB004, a monoclonal antibody targeting the unique tumor-associated form of MUC1 (tMUC1) in the early detection of PDA. In this study, we evaluated the therapeutic benefit of combining the TAB004 antibody with Liposomal-MSA-IL-2 in immune competent and human MUC1 transgenic (MUC1.Tg) mouse models of PDA and investigated the associated immune responses. Treatment with TAB004 + Lip-MSA-IL-2 resulted in significantly improved survival and slower tumor growth compared to controls in MUC1.Tg mice bearing an orthotopic PDA.MUC1 tumor. Similarly, in the spontaneous model of PDA that expresses human MUC1, the combination treatment stalled the progression of pancreatic intraepithelial pre-neoplastic (PanIN) lesion to adenocarcinoma. Treatment with the combination elicited a robust systemic and tumor-specific immune response with (a) increased percentages of systemic and tumor infiltrated CD45+CD11b+ cells, (b) increased levels of myeloperoxidase (MPO), (c) increased antibody-dependent cellular cytotoxicity/phagocytosis (ADCC/ADCP), (d) decreased percentage of immune regulatory cells (CD8+CD69+ cells), and (e) reduced circulating levels of immunosuppressive tMUC1. We report that treatment with a novel antibody against tMUC1 in combination with a unique formulation of IL-2 can improve survival and lead to stable disease in appropriate models of PDA by reducing tumor-induced immune regulation and promoting recruitment of CD45+CD11b+ cells, thereby enhancing ADCC/ADCP.

Inhibition of geranylgeranyl diphosphate synthase is a novel therapeutic strategy for pancreatic ductal adenocarcinoma

Rab proteins play an essential role in regulating intracellular membrane trafficking processes. Rab activity is dependent upon geranylgeranylation, a post-translational modification that involves the addition of 20-carbon isoprenoid chains via the enzyme geranylgeranyl transferase (GGTase) II. We have focused on the development of inhibitors against geranylgeranyl diphosphate synthase (GGDPS), which generates the isoprenoid donor (GGPP), as anti-Rab agents. Pancreatic ductal adenocarcinoma (PDAC) is characterized by abnormal mucin production and these mucins play important roles in tumor development, metastasis and chemo-resistance. We hypothesized that GGDPS inhibitor (GGDPSi) treatment would induce PDAC cell death by disrupting mucin trafficking, thereby inducing the unfolded protein response pathway (UPR) and apoptosis. To this end, we evaluated the effects of RAM2061, a potent GGDPSi, against PDAC. Our studies revealed that GGDPSi treatment activates the UPR and triggers apoptosis in a variety of human and mouse PDAC cell lines. Furthermore, GGDPSi treatment was found to disrupt the intracellular trafficking of key mucins such as MUC1. These effects could be recapitulated by incubation with a specific GGTase II inhibitor, but not a GGTase I inhibitor, consistent with the effect being dependent on disruption of Rab-mediated activities. In addition, siRNA-mediated knockdown of GGDPS induces upregulation of UPR markers and disrupts MUC1 trafficking in PDAC cells. Experiments in two mouse models of PDAC demonstrated that GGDPSi treatment significantly slows tumor growth. Collectively, these data support further development of GGDPSi therapy as a novel strategy for the treatment of PDAC.

Prognostic and clinicopathological value of MUC1 expression in colorectal cancer: A meta-analysis

BACKGROUND

Accumulating evidence supports the overexpression of mucin 1 (MUC1) in colorectal cancer (CRC), but the value of elevated MUC1 expression remains controversial. Here, we evaluated the prognostic and clinicopathological value of MUC1 expression in CRC.

MATERIALS AND METHODS

The Web of Science, PubMed, Embase, Cochrane Library, and Wanfang databases, as well as the China Biology Medicine disc (CBMdisc) and China National Knowledge Infrastructure (CNKI) were searched for studies on MUC1 expression and prognosis of CRC through July 20, 2018. The pooled relative risks (RRs) and hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated to evaluate the prognostic and clinicopathological value of MUC1 expression in CRC. The Revman version 5.3 package and STATA, version 12 were employed for pooled analysis and analysis of publication bias.

RESULTS

This meta-analysis included 16 published studies. The combined analysis showed that CRC patients with high MUC1 expression had a worse clinical outcome in overall survival (OS) (HR = 1.51, 95% CI = 1.30-1.75, P <.00001). In addition, high MUC1 expression was associated with higher TNM stage (RR = 1.44, 95% CI = 1.17-1.77, P = .0007), greater depth of invasion (RR = 1.30, 95% CI = 1.10-1.53, P = .002), and lymph node metastasis (RR = 1.47, 95% CI = 1.20-1.80, P = .0002) of CRC. However, the elevated MUC1 expression was not related to disease-free survival/recurrence-free survival (DFS/RFS) (HR = 1.51, 95% CI = 0.78-2.89, P = .22), histological grade (RR = 1.15, 95% CI = 0.96-1.38, P = .12), gender (RR = 0.95; 95% CI = 0.83-1.08, P = .44), tumor size (RR = 1.11, 95% CI = 0.85-1.44, P = .44), tumor site (RR = 1.01, 95% CI = 0.88-1.16, P = .84), or mucinous component (RR = 0.83, 95% CI = 0.60-1.14, P = .24) in CRC.

CONCLUSION

Our findings indicated that high MUC1 expression represents a marker of poor prognosis in CRC. Meanwhile, elevated MUC1 expression was associated with advanced TNM stage, greater depth of invasion, and lymph node metastasis.

Immunotherapy: Pancreatic Cancer and Extrahepatic Biliary Tract Cancer

Pancreatic ductal adenocarcinoma (PDAC) and extrahepatic biliary tract cancer (BTC) are among the malignancies with the highest morbidity and mortality. Despite increasing knowledge on biology and novel therapies, outcome remains poor in these patients. Recent progress in immunotherapies created new hopes in the treatment of PDAC and extrahepatic BTC. Several trials tested immunotherapies in various therapeutic situations as monotherapies or in combinations. Although responses were seen in some of the trials, the value of immunotherapy in PDAC and extrahepatic BTC remains unclear in the current situation, especially regarding the complex biological characteristics with a high stroma component, intrinsic resistance mechanisms and an immunosuppressive, hypoxic microenvironment. These major hurdles have to be taken into account and overcome if immunotherapies should be successful in these tumor entities. Thereby, combinational approaches that allow on the one hand targeted therapy and on the other restore or boost the function of immune cells are promising.

Targeting both tumour-associated CXCR2+ neutrophils and CCR2+ macrophages disrupts myeloid recruitment and improves chemotherapeutic responses in pancreatic ductal adenocarcinoma

OBJECTIVE

Chemokine pathways are co-opted by pancreatic adenocarcinoma (PDAC) to facilitate myeloid cell recruitment from the bone marrow to establish an immunosuppressive tumour microenvironment (TME). Targeting tumour-associated CXCR2⁺neutrophils (TAN) or tumour-associated CCR2⁺ macrophages (TAM) alone improves antitumour immunity in preclinical models. However, a compensatory influx of an alternative myeloid subset may result in a persistent immunosuppressive TME and promote therapeutic resistance. Here, we show CCR2 and CXCR2 combined blockade reduces total tumour-infiltrating myeloids, promoting a more robust antitumour immune response in PDAC compared with either strategy alone.

METHODS

Blood, bone marrow and tumours were analysed from PDAC patients and controls. Treatment response and correlative studies were performed in mice with established orthotopic PDAC tumours treated with a small molecule CCR2 inhibitor (CCR2i) and CXCR2 inhibitor (CXCR2i), alone and in combination with chemotherapy.

RESULTS

A systemic increase in CXCR2⁺ TAN correlates with poor prognosis in PDAC, and patients receiving CCR2i showed increased tumour-infiltrating CXCR2⁺ TAN following treatment. In an orthotopic PDAC model, CXCR2 blockade prevented neutrophil mobilisation from the circulation and augmented chemotherapeutic efficacy. However, depletion of either CXCR2⁺ TAN or CCR2⁺ TAM resulted in a compensatory response of the alternative myeloid subset, recapitulating human disease. This was overcome by combined CCR2i and CXCR2i, which augmented antitumour immunity and improved response to FOLFIRINOX chemotherapy.

CONCLUSION

Dual targeting of CCR2⁺ TAM and CXCR2⁺ TAN improves antitumour immunity and chemotherapeutic response in PDAC compared with either strategy alone.

Treatment of pancreatic ductal adenocarcinoma with tumor antigen specific-targeted delivery of paclitaxel loaded PLGA nanoparticles

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) remains the most aggressive cancers with a 5-year survival below 10%. Systemic delivery of chemotherapy drugs has severe side effects in patients with PDA and does not significantly improve overall survival rate. It is highly desirable to advance the therapeutic efficacy of chemotherapeutic drugs by targeting their delivery and increasing accumulation at the tumor site. MUC1 is a membrane-tethered glycoprotein that is aberrantly overexpressed in > 80% of PDA thus making it an attractive antigenic target.

METHODS

Poly lactic-co-glycolic acid nanoparticles (PLGA NPs) conjugated to a tumor specific MUC1 antibody, TAB004, was used as a nanocarrier for targeted delivery into human PDA cell lines in vitro and in PDA tumors in vivo. The PLGA NPs were loaded with fluorescent imaging agents, fluorescein diacetate (FDA) and Nile Red (NR) or isocyanine green (ICG) for in vitro and in vivo imaging respectively or with a chemotherapeutic drug, paclitaxel (PTX) for in vitro cytotoxicity assays. Confocal microscopy was used to visualize internalization of the nanocarrier in vitro in PDA cells with high and low MUC1 expression. The in vivo imaging system (IVIS) was used to visualize in vivo tumor targeting of the nanocarrier. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay was used to determine in vitro cell survival of cells treated with PTX-loaded nanocarrier. One-sided t-test comparing treatment groups at each concentration and two-way ANOVAs comparing internalization of antibody and PLGA nanoparticles.

RESULTS

In vitro, TAB004-conjugated ICG-nanocarriers were significantly better at internalizing in PDA cells than its non-conjugated counterpart. Similarly, TAB004-conjugated PTX-nanocarriers were significantly more cytotoxic in vitro against PDA cells than its non-conjugated counterpart. In vivo, TAB004-conjugated ICG-nanocarriers showed increased accumulation in the PDA tumor compared to the non-conjugated nanocarrier while sparing normal organs.

CONCLUSIONS

The study provides promising data for future development of a novel MUC1-targeted nanocarrier for direct delivery of imaging agents or drugs into the tumor microenvironment.

Novel roles for mucin 1 in the kidney

PURPOSE OF REVIEW

Recent studies in the kidney have revealed that the well characterized tumor antigen mucin 1 (MUC1/Muc1) also has numerous functions in the normal and injured kidney.

RECENT FINDINGS

Mucin 1 is a transmembrane mucin with a robust glycan-dependent apical targeting signal and efficient recycling from endosomes. It was recently reported that the TRPV5 calcium channel is stabilized on the cell surface by galectin-dependent cross-linking to mucin 1, providing a novel mechanism for regulation of ion channels and normal electrolyte balance.Our recent studies in mice show that Muc 1 is induced after ischemia, stabilizing hypoxia-inducible factor 1 (HIF-1)α and β-catenin levels, and transactivating the HIF-1 and β-catenin protective pathways. However, prolonged induction of either pathway in the injured kidney can proceed from apparent full recovery to chronic kidney disease. A very recent report indicates that aberrant activation of mucin 1 signaling after ischemic injury in mice and humans is associated with development of chronic kidney disease and fibrosis. A frameshift mutation in MUC1 was recently identified as the genetic lesion causing medullary cystic kidney disease type 1, now appropriately renamed MUC1 Kidney Disease.

SUMMARY

Studies of mucin 1 in the kidney now reveal significant functions for the extracellular mucin-like domain and signaling through the cytoplasmic tail.

Early detection of pancreatic cancer in mouse models using a novel antibody, TAB004

Pancreatic ductal adenocarcinoma (PDA) is the fourth-leading cause of cancer death in the United States with a 5-year overall survival rate of 8% for all stages combined. But this decreases to 3% for the majority of patients that present with stage IV PDA at time of diagnosis. The lack of distinct early symptoms for PDA is one of the primary reasons for the late diagnosis. Common symptoms like weight loss, abdominal and back pains, and jaundice are often mistaken for symptoms of other issues and do not appear until the cancer has progressed to a late stage. Thus the development of novel imaging platforms for PDA is crucial for the early detection of the disease. MUC1 is a tumor-associated antigen (tMUC1) expressed on 80% of PDA. The goal of this study was to determine the targeting and detection capabilities of a tMUC1 specific antibody, TAB004. TAB004 antibody conjugated to a near infrared fluorescent probe was injected intraperitoneally into immune competent orthotopic and spontaneous models of PDA. Results show that fluorophore conjugated TAB004 specifically targets a) 1 week old small tumor in the pancreas in an orthotopic PDA model and b) very early pre-neoplastic lesions (PanIN lesions) that develop in the spontaneous PDA model before progression to adenocarcinoma. Thus, TAB004 is a promising antibody to deliver imaging agents directly to the pancreatic tumor microenvironment, significantly affecting early detection of PDA.

Conjugation to the sigma-2 ligand SV119 overcomes uptake blockade and converts dm-Erastin into a potent pancreatic cancer therapeutic

Cancer-selective drug delivery is an important concept in improving treatment while minimizing off-site toxicities, and sigma-2 receptors, which are overexpressed in solid tumors, represent attractive pharmacologic targets. Select sigma-2 ligands have been shown to be rapidly internalized selectively into cancer cells while retaining the capacity to deliver small molecules as drug cargoes. We utilized the sigma-2-based drug delivery concept to convert Erastin, a clinically underperforming drug, into a potent pancreatic cancer therapeutic. The Erastin derivative des-methyl Erastin (dm-Erastin) was chemically linked to sigma-2 ligand SV119 to create SW V-49. Conjugation increased the killing capacity of dm-Erastin by nearly 35-fold in vitro and reduced the size of established tumors and doubled the median survival in syngeneic and patient-derived xenograft models when compared to non-targeted dm-Erastin. Mechanistic analyses demonstrated that cell death was associated with robust reactive oxygen species production and could be efficiently antagonized with antioxidants. Mass spectrometry was employed to demonstrate selective uptake into pancreatic cancer cells. Thus, targeted delivery of dm-Erastin via conjugation to the sigma-2 ligand SV119 produced efficient tumor control and prolonged animal survival with minimal off-target toxicities, and SW V-49 represents a promising new therapeutic with the potential to advance the fight against pancreatic cancer.

Mucus models to evaluate the diffusion of drugs and particles

Mucus is a complex hydrogel that acts as a natural barrier to drug delivery at different mucosal surfaces including the respiratory, gastrointestinal, and vaginal tracts. To elucidate the role mucus plays in drug delivery, different in vitro, in vivo, and ex vivo mucus models and techniques have been utilized. Drug and drug carrier diffusion can be studied using various techniques in either isolated mucus gels or mucus present on cell cultures and tissues. The species, age, and potential disease state of the animal from which mucus is derived can all impact mucus composition and structure, and therefore impact drug and drug carrier diffusion. This review provides an overview of the techniques used to characterize drug and drug carrier diffusion, and discusses the advantages and disadvantages of the different models available to highlight the information they can afford.

Inhibition of MUC1 biosynthesis via threonyl-tRNA synthetase suppresses pancreatic cancer cell migration

Mucin1 (MUC1), a heterodimeric oncoprotein, containing tandem repeat structures with a high proportion of threonine, is aberrantly overexpressed in many human cancers including pancreatic cancer. Since the overall survival rate of pancreatic cancer patients has remained low for several decades, novel therapeutic approaches are highly needed. Intestinal mucin has been known to be affected by dietary threonine supply since de novo synthesis of mucin proteins is sensitive to luminal threonine concentration. However, it is unknown whether biosynthesis of MUC1 is regulated by threonine in human cancers. In this study, data provided suggests that threonine starvation reduces the level of MUC1 and inhibits the migration of MUC1-expressing pancreatic cancer cells. Interestingly, knockdown of threonyl-tRNA synthetase (TRS), an enzyme that catalyzes the ligation of threonine to its cognate tRNA, also suppresses MUC1 levels but not mRNA levels. The inhibitors of TRS decrease the level of MUC1 protein and prohibit the migration of MUC1-expressing pancreatic cancer cells. In addition, a positive correlation between TRS and MUC1 levels is observed in human pancreatic cancer cells. Concurrent with these results, the bioinformatics data indicate that co-expression of both TRS and MUC1 is correlated with the poor survival of pancreatic cancer patients. Taken together, these findings suggest a role for TRS in controlling MUC1-mediated cancer cell migration and provide insight into targeting TRS as a novel therapeutic approach to pancreatic cancer treatment.

Muc1 knockout potentiates murine lung carcinogenesis involving an epiregulin-mediated EGFR activation feedback loop

Mucin 1 (MUC1) is a tumor antigen that is aberrantly overexpressed in various cancers, including lung cancer. Our previous in vitro studies showed that MUC1 facilitates carcinogen-induced EGFR activation and transformation in human lung bronchial epithelial cells (HBECs), which along with other reports suggests an oncogenic property for MUC1 in lung cancer. However, direct evidence for the role of MUC1 in lung carcinogenesis is lacking. In this study, we used the 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced A/J mouse lung tumor model to investigate the effect of whole-body Muc1 knockout (KO) on carcinogen-induced lung carcinogenesis. Surprisingly, lung tumor multiplicity was significantly increased in Muc1 KO compared to wild-type (WT) mice. The EGFR/AKT pathway was unexpectedly activated, and expression of the EGFR ligand epiregulin (EREG) was increased in the lung tissues of the Muc1 KO compared to the WT mice. EREG stimulated proliferation and protected against cigarette smoke extract (CSE)-induced cytotoxicity in in vitro cultured human bronchial epithelial cells. Additionally, we determined that MUC1 was expressed in human fibroblast cell lines where it suppressed CSE-induced EREG production. Further, suppression of MUC1 cellular activity with GO-201 enhanced EREG production in lung cancer cells, which in turn protected cancer cells from GO-201-induced cell death. Moreover, an inverse association between MUC1 and EREG was detected in human lung cancer, and EREG expression was inversely associated with patient survival. Together, these results support a promiscuous role of MUC1 in lung cancer development that may be related to cell-type specific functions of MUC1 in the tumor microenvironment, and MUC1 deficiency in fibroblasts and malignant cells results in increased EREG production that activates the EGFR pathway for lung carcinogenesis.

MUC1-Mediated Metabolic Alterations Regulate Response to Radiotherapy in Pancreatic Cancer

Purpose:MUC1, an oncogene overexpressed in multiple solid tumors, including pancreatic cancer, reduces overall survival and imparts resistance to radiation and chemotherapies. We previously identified that MUC1 facilitates growth-promoting metabolic alterations in pancreatic cancer cells. The present study investigates the role of MUC1-mediated metabolism in radiation resistance of pancreatic cancer by utilizing cell lines and in vivo models.Experimental Design: We used MUC1-knockdown and -overexpressed cell line models for evaluating the role of MUC1-mediated metabolism in radiation resistance through in vitro cytotoxicity, clonogenicity, DNA damage response, and metabolomic evaluations. We also investigated whether inhibition of glycolysis could revert MUC1-mediated metabolic alterations and radiation resistance by using in vitro and in vivo models.Results: MUC1 expression diminished radiation-induced cytotoxicity and DNA damage in pancreatic cancer cells by enhancing glycolysis, pentose phosphate pathway, and nucleotide biosynthesis. Such metabolic reprogramming resulted in high nucleotide pools and radiation resistance in in vitro models. Pretreatment with the glycolysis inhibitor 3-bromopyruvate abrogated MUC1-mediated radiation resistance both in vitro and in vivo, by reducing glucose flux into nucleotide biosynthetic pathways and enhancing DNA damage, which could again be reversed by pretreatment with nucleoside pools.Conclusions: MUC1-mediated nucleotide metabolism plays a key role in facilitating radiation resistance in pancreatic cancer and targeted effectively through glycolytic inhibition. Clin Cancer Res; 23(19); 5881-91. ©2017 AACR.

Mucins in pancreatic cancer: biological role, implications in carcinogenesis and applications in diagnosis and therapy

Pancreatic cancer is the fourth highest cause of cancer mortality in the world. It has very low survival rates owing to late diagnosis resulting from the absence of accurate diagnostic tools and effective therapies. Hence, there is a pressing need to develop new diagnostic and therapeutic tools. In the recent years, there has been new evidence implicating the importance of mucins in pancreatic carcinogenesis. Mucins belong to a group of heavily glycosylated proteins, and are often aberrantly expressed in a number of cancers such as pancreatic cancer. Therefore, this literature review will summarise the role of mucins and mucin expression in pancreatic neoplasms. Subsequently the paper will also discuss the most recent advances in the biological properties of mucins and their role in carcinogenesis and resistance to chemotherapy. Then it will conclude on the newest developments in diagnosis and therapy based on mucins for pancreatic cancer.

A tumor specific antibody to aid breast cancer screening in women with dense breast tissue

Screening for breast cancer has predominantly been done using mammography. Unfortunately, mammograms miss 50% cancers in women with dense breast tissue. Multi-modal screenings offer the best chance of enhancing breast cancer screening effectiveness. We evaluated the use of TAB004, an antibody that recognizes the tumor form of the glycoprotein MUC1 (tMUC1), to aid early detection of breast cancer. Our experimental approach was to follow tMUC1 from the tissue into circulation. We found that 95% of human breast cancer tissues across all subtypes stained positive for TAB004. In breast cancer cell lines, we showed that the amount of tMUC1 released from tumor cells is proportional to the cell's tMUC1 expression level. Finally, we showed that TAB004 can be used to assess circulating tMUC1 levels, which when monitored in the context of cancer immunoediting, can aid earlier diagnosis of breast cancer regardless of breast tissue density. In a blinded pilot study with banked serial samples, tMUC1 levels increased significantly up to 2 years before diagnosis. Inclusion of tMUC1 monitoring as part of a multi-modal screening strategy may lead to earlier stage diagnosis of women whose cancers are missed by mammography.

Key biological processes driving metastatic spread of pancreatic cancer as identified by multi-omics studies

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive malignancy, characterized by a high metastatic burden, already at the time of diagnosis. The metastatic potential of PDAC is one of the main reasons for the poor outcome next to lack of significant improvement in effective treatments in the last decade. Key mutated driver genes, such as activating KRAS mutations, are concordantly expressed in primary and metastatic tumors. However, the biology behind the metastatic potential of PDAC is not fully understood. Recently, large-scale omic approaches have revealed new mechanisms by which PDAC cells gain their metastatic potency. In particular, genomic studies have shown that multiple heterogeneous subclones reside in the primary tumor with different metastatic potential. The development of metastases may be correlated to a more mesenchymal transcriptomic subtype. However, for cancer cells to survive in a distant organ, metastatic sites need to be modulated into pre-metastatic niches. Proteomic studies identified the influence of exosomes on the Kuppfer cells in the liver, which could function to prepare this tissue for metastatic colonization. Phosphoproteomics adds an extra layer to the established omic techniques by unravelling key functional signaling. Future studies integrating results from these large-scale omic approaches will hopefully improve PDAC prognosis through identification of new therapeutic targets and patient selection tools. In this article, we will review the current knowledge on the biology of PDAC metastasis unravelled by large scale multi-omic approaches.

SERS- and luminescence-active Au-Au-UCNP trimers for attomolar detection of two cancer biomarkers

Alpha-fetoprotein (AFP) and mucoprotein1 (mucin-1) are two important disease biomarkers. Self-assembled gold nanoparticles (AuNPs) and upconversion nanoparticle (Au-Au-UCNP) trimers based on aptamers were developed for the ultrasensitive detection of AFP and mucin-1. The Au-Au-UCNP trimers produced ideal optical signals, with prominent Raman enhancement and fluorescence quenching effects. The surface-enhanced Raman scattering (SERS) intensity decreased in the presence of mucin-1 and the luminescence intensity increased in the presence of AFP. A limit of detection (LOD) of 4.1 aM and a wide linear range of 0.01-10 fM for the detection of mucin-1 were obtained with this SERS-encoded sensing system. Using the luminescence-encoded sensing system, a LOD of 0.059 aM and a wide linear range of 1-100 aM for the detection of AFP were obtained. These LODs are the lowest values reported so far. This approach has the advantage of detecting two disease biomarkers simultaneously.

Sigma-2 receptor agonist derivatives of 1-Cyclohexyl-4-[3-(5-methoxy-1,2,3,4-tetrahydronaphthalen-1-yl)propyl]piperazine (PB28) induce cell death via mitochondrial superoxide production and caspase activation in pancreatic cancer

Background

Despite considerable efforts by scientific research, pancreatic cancer is the fourth leading cause of cancer related mortalities. Sigma-2 receptors, which are overexpressed in several tumors, represent promising targets for triggering selective pancreatic cancer cells death.

Methods

We selected five differently structured high-affinity sigma-2 ligands (PB28, PB183, PB221, F281 and PB282) to study how they affect the viability of diverse pancreatic cancer cells (human cell lines BxPC3, AsPC1, Mia PaCa-2, and Panc1 and mouse Panc-02, KCKO and KP-02) and how this is reflected in vivo in a tumor model.

Results

Important cytotoxicity was shown by the compounds in the aggressive Panc02 cells, where cytotoxic activity was caspase-3 independent for four of the five compounds. However, both cytotoxicity and caspase-3 activation involved generation of Reactive Oxygen Species (ROS), which could be partially reverted by the lipid antioxidant α-tocopherol, but not by the hydrophilic N-acetylcysteine (NAC) indicating crucial differences in the intracellular sites exposed to oxidative stress induced by sigma-2 receptor ligands. Importantly, all the compounds strongly increased the production of mitochondrial superoxide radicals except for PB282. Despite a poor match between in vitro and the in vivo efficacy, daily treatment of C57BL/6 mice bearing Panc02 tumors resulted in promising effects with PB28 and PB282 which were similar compared to the current standard-of-care chemotherapeutic gemcitabine without showing signs of systemic toxicities.

Conclusions

Overall, this study identified differential sensitivities of pancreatic cancer cells to structurally diverse sigma-2 receptor ligands. Of note, we identified the mitochondrial superoxide pathway as a previously unrecognized sigma-2 receptor-activated process, which encourages further studies on sigma-2 ligand-mediated cancer cell death for the targeted treatment of pancreatic tumors.

Immunotherapy in pancreatic cancer treatment: a new frontier

Pancreatic cancer is a highly aggressive and lethal cancer characterized by high invasiveness, local and extensive dissemination at time of diagnosis and resistance to treatment. Few therapies have shown efficacy in the past and even standard of care therapies yield only modest improvements in the mortality of patients with advanced or metastatic disease. Efforts have been undertaken to study the pancreatic tumor microenvironment and have established its complex and immunosuppressive nature which could explain the high resistance to chemotherapy. Novel therapies targeting the tumor microenvironment with an aim to decrease this resistance, improve immune tolerance and increase the efficacy of the current treatment have shown some promising preliminary results in preclinical and clinical trials. We review the current advances in the field of immunotherapy and their effectiveness as a potential treatment strategy in the pancreatic cancer.

Genetically engineered mucin mouse models for inflammation and cancer

Mucins are heavily O-glycosylated proteins primarily produced by glandular and ductal epithelial cells, either in membrane-tethered or secretory forms, for providing lubrication and protection from various exogenous and endogenous insults. However, recent studies have linked their aberrant overexpression with infection, inflammation, and cancer that underscores their importance in tissue homeostasis. In this review, we present current status of the existing mouse models that have been developed to gain insights into the functional role(s) of mucins under physiological and pathological conditions. Knockout mouse models for membrane-associated (Muc1 and Muc16) and secretory mucins (Muc2) have helped us to elucidate the role of mucins in providing effective and protective barrier functions against pathological threats, participation in disease progression, and improved our understanding of mucin interaction with biotic and abiotic environmental components. Emphasis is also given to available transgenic mouse models (MUC1 and MUC7), which has been exploited to understand the context-dependent regulation and therapeutic potential of human mucins during inflammation and cancer.