MUC1-induced transcriptional programs associated with tumorigenesis predict outcome in breast and lung cancer

MUC1-C Is a Common Driver of Acquired Osimertinib Resistance in NSCLC

INTRODUCTION

Osimertinib is an irreversible EGFR tyrosine kinase inhibitor approved for the first-line treatment of patients with metastatic NSCLC harboring EGFR exon 19 deletions or L858R mutations. Patients treated with osimertinib invariably develop acquired resistance by mechanisms involving additional EGFR mutations, MET amplification, and other pathways. There is no known involvement of the oncogenic MUC1-C protein in acquired osimertinib resistance.

METHODS

H1975/EGFR (L858R/T790M) and patient-derived NSCLC cells with acquired osimertinib resistance were investigated for MUC1-C dependence in studies of EGFR pathway activation, clonogenicity, and self-renewal capacity.

RESULTS

We reveal that MUC1-C is up-regulated in H1975 osimertinib drug-tolerant persister cells and is necessary for activation of the EGFR pathway. H1975 cells selected for stable osimertinib resistance (H1975-OR) and MGH700-2D cells isolated from a patient with acquired osimertinib resistance are found to be dependent on MUC1-C for induction of (1) phospho (p)-EGFR, p-ERK, and p-AKT, (2) EMT, and (3) the resistant phenotype. We report that MUC1-C is also required for p-EGFR, p-ERK, and p-AKT activation and self-renewal capacity in acquired osimertinib-resistant (1) MET-amplified MGH170-1D #2 cells and (2) MGH121 Res#2/EGFR (T790M/C797S) cells. Importantly, targeting MUC1-C in these diverse models reverses osimertinib resistance. In support of these results, high MUC1 mRNA and MUC1-C protein expression is associated with a poor prognosis for patients with EGFR-mutant NSCLCs.

CONCLUSIONS

Our findings reveal that MUC1-C is a common effector of osimertinib resistance and is a potential target for the treatment of osimertinib-resistant NSCLCs.

Single CAR-T cell treatment controls disseminated ovarian cancer in a syngeneic mouse model

BACKGROUND

Treatment of some blood cancers with T cells that express a chimeric antigen receptor (CAR) against CD19 have shown remarkable results. In contrast, CAR-T cell efficacy against solid tumors has been difficult to achieve.

METHODS

To examine the potential of CAR-T cell treatments against ovarian cancers, we used the mouse ovarian cancer cell line ID8 in an intraperitoneal model that exhibits disseminated solid tumors in female C57BL/6J mice. The CAR contained a single-chain Fv from antibody 237 which recognizes a Tn-glycopeptide-antigen expressed by ID8 due to aberrant O-linked glycosylation in the absence of the transferase-dependent chaperone Cosmc. The efficacy of four Tn-dependent CARs with varying affinity to Tn antigen, and each containing CD28/CD3ζ cytoplasmic domains, were compared in vitro and in vivo in this study.

RESULTS

In line with many observations about the impact of aberrant O-linked glycosylation, the ID8Cosmc knock-out (ID8Cosmc-KO) exhibited more rapid tumor progression compared with wild-type ID8. Despite the enhanced tumor growth in vivo, 237 CAR and a mutant with 30-fold higher affinity, but not CARs with lower affinity, controlled advanced ID8Cosmc-KO tumors. Tumor regression could be achieved with a single intravenous dose of the CARs, but intraperitoneal administration was even more effective. The CAR-T cells persisted over a period of months, allowing CAR-treated mice to delay tumor growth in a re-challenge setting. The most effective CARs exhibited the highest affinity for antigen. Antitumor effects observed in vivo were associated with increased numbers of T cells and macrophages, and higher levels of cleaved caspase-3, in the tumor microenvironment. Notably, the least therapeutically effective CAR mediated tonic signaling leading to antigen-independent cytokine expression and it had higher levels of the immunosuppressive cytokine interleukin10.

CONCLUSION

The findings support the development of affinity-optimized CAR-T cells as a potential treatment for established ovarian cancer, with the most effective CARs mediating a distinct pattern of inflammatory cytokine release in vitro. Importantly, the most potent Tn-dependent CAR-T cells showed no evidence of toxicity in tumor-bearing mice in a syngeneic, immunocompetent system.

Possible correlation of apical localization of MUC1 glycoprotein with luminal A-like status of breast cancer

Adjuvant chemotherapy has played a major role in the treatment of hormone receptor-positive breast cancer for many years. To better determine which patient subsets need adjuvant chemotherapy, various gene expression analyses have been developed, but cost-effective tools to identify such patients remain elusive. In the present report, we retrospectively investigated immunohistochemical expression and subcellular localization of MUC1 in primary tumors and examined their relationship to tumor malignancy, chemotherapy effect and patient outcomes. We retrospectively examined three patient cohorts with hormone receptor-positive/human epidermal growth factor receptor 2-negative invasive breast cancer: 51 patients who underwent 21-gene expression analysis (multi-gene assay-cohort), 96 patients who received neoadjuvant chemotherapy (neoadjuvant chemotherapy-cohort), and 609 patients whose tumor tissue was used in tissue-microarrays (tissue-microarray-cohort). The immunohistochemical staining pattern of the anti-MUC1 monoclonal antibody, Ma695, was examined in cancer tissues, and subcellular localization was determined as apical, cytoplasmic or negative. In the multi-gene assay-cohort, tumors with apical patterns had the lowest recurrence scores, reflecting lower tumor malignancy, and were significantly lower than MUC1-negative tumors (P = 0.038). In the neoadjuvant chemotherapy-cohort, there was no correlation between MUC1 staining patterns and effects of chemotherapy. Finally, in the tissue-microarray-cohort, we found that patients with apical MUC1 staining patterns had significantly longer disease-free-survival and overall survival than other patterns (P = 0.020 and 0.039, respectively). Our data suggest that an apical MUC1 staining pattern indicates luminal A-likeness. Assessment of the subcellular localization of MUC1 glycoprotein may be useful for identifying patients who can avoid adjuvant chemotherapy.

MUC1 Expressions and Its Prognostic Values in US Gastric Cancer Patients

This study aims to evaluate the prognostic value of MUC expression in US GC patients. A total of 70 tumor specimens were collected from GC patients who underwent surgery or endoscopic resection between 2013 and 2019 at a tertiary referral center in the US. MUC expression status including MUC1, MUC2, MUC5AC, and MUC6 was evaluated by immunohistochemical staining. The positive rates of MUC1, MUC2, MUC5AC, and MUC6 were 71.4%, 78.6%, 74.3%, and 33.3%, respectively. Patients with positive MUC1 expression had a significantly higher rate of aggressive pathologic features including diffuse-type cancer (42.0% vs. 0%; p < 0.001), advanced GC (80.0% vs. 30.0%, p < 0.001), lymph node metastasis (62.0% vs. 20.0%; p = 0.001), and distant metastasis (32.0% vs. 5.0%; p = 0.017) compared with those with negative MUC1 expression. However, the differences in the pathologic features were not observed according to MUC2, MUC5AC, and MUC6 expression status. In early gastric cancer (EGC), patients with a high level of MUC1 expression showed a higher rate of lymphovascular invasion (71.4% vs. 21.4%; p = 0.026) and EGC meeting non-curative resection (85.7% vs. 42.9%; p = 0.061) than those with negative MUC1. In US GC patients, MUC1 expression is associated with aggressive pathological features, and might be a useful prognostic marker.

MUC1 is a potential target to overcome trastuzumab resistance in breast cancer therapy

Although resistance is its major obstacle in cancer therapy, trastuzumab is the most successful agent in treating epidermal growth factor receptor 2 positive (HER2 +) breast cancer (BC). Some patients show resistance to trastuzumab, and scientists want to circumvent this problem. This review elaborately discusses possible resistance mechanisms to trastuzumab and introduces mucin 1 (MUC1) as a potential target efficient for overcoming such resistance. MUC1 belongs to the mucin family, playing the oncogenic/mitogenic roles in cancer cells and interacting with several other oncogenic receptors and pathways, such as HER2, β-catenin, NF-κB, and estrogen receptor (ERα). Besides, it has been established that MUC1- Cytoplasmic Domain (MUC1-CD) accelerates the development of resistance to trastuzumab and that silencing MUC1-C proto-oncogene is associated with increased sensitivity of HER2⁺ cells to trastuzumab-induced growth inhibitors. We mention why targeting MUC1 can be useful in overcoming trastuzumab resistance in cancer therapy.

Inhalable polymeric micro and nano-immunoadjuvants for developing therapeutic vaccines in the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a leading cause of death in millions of cancer patients. Lack of diagnosis at an early stage in addition to no specific guidelines for its treatment, and a higher rate of treatment-related toxicity further deteriorate the conditions. Current therapies encompass surgery, chemotherapy, radiation therapy, and immunotherapy according to the pattern and the stage of lung cancer. Among all, with a longlasting therapeutic action, reduced side-effects, and a higher rate of survival, therapeutic cancer vaccine is a new, improved strategy for treating NSCLC. Immunoadjuvants are usually incorporated into the therapeutic vaccines to shield the antigen against environmental and physiological harsh conditions in addition to boosting the immune potential. Conventional immunoadjuvants are often associated with an inadequate cellular response, poor target specificity, and low antigen load. Recently, inhalable polymeric nano/micro immunoadjuvants have exhibited immense potential in the development of therapeutic vaccines for the treatment of NSCLC with improved mucosal immunization. The development of polymeric micro/nano immunoadjuvants brought a new era for vaccines with increased strength and efficiency. Therefore, in the present review, we explained the potential application of micro/nano immunoadjuvants for augmenting the stability and efficacy of inhalable vaccines in the treatment of NSCLC. In addition, the role of biodegradable, biocompatible, and non-toxic polymers has also been discussed with case studies.

MUC1-C in chronic inflammation and carcinogenesis; emergence as a target for cancer treatment

Chronic inflammation is a highly prevalent consequence of changes in environmental and lifestyle factors that contribute to the development of cancer. The basis for this critical association has largely remained unclear. The MUC1 gene evolved in mammals to protect epithelia from the external environment. The MUC1-C subunit promotes responses found in wound healing and cancer. MUC1-C induces EMT, epigenetic reprogramming, dedifferentiation and pluripotency factor expression, which when prolonged in chronic inflammation promote cancer progression. As discussed in this review, MUC1-C also drives drug resistance and immune evasion, and is an important target for cancer therapeutics now under development.

Core 2 β1,6-N-acetylglucosaminyltransferases accelerate the escape of choriocarcinoma from natural killer cell immunity

Hyperglycosylated human chorionic gonadotropin (H-hCG) is secreted from choriocarcinoma and contains a core2 O-glycan formed by core2 β1,6-N-acetylglucosaminyl transferase (C2GnT). Choriocarcinoma is considered immunogenic as it is gestational and contains paternal chromosomal components. Here we examined the function of C2GnT in the evasion of choriocarcinoma cells from natural killer (NK) cell-mediating killing. We determined that C2GnT is highly expressed in malignant gestational trophoblastic neoplasms. C2GnT KO downregulates core2 O-glycan expression in choriocarcinoma cells, which are more efficiently killed by NK cells than control cells. C2GnT KO cell containing tumor necrosis factor-related apoptosis inducing ligand have lower viability than control cells. Additionally, poly-N-acetyllactosamine in core2 branched oligosaccharides on MHC class I-related chain A (MICA) and mucin1 (MUC1) is significantly reduced in C2GnT KO cells. Meanwhile, the cumulative survival rate of nude mice inoculated with C2GnT KO tumors was higher than that of the control group. These findings suggest that choriocarcinoma cells may escape NK cell-mediated killing via glycosylation of MICA and MUC1.

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C2GnT knockout reduces core2 O-glycan expression in choriocarcinoma cells

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C2GnT KO cells are more readily killed by NK cells

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C2GnT KO cells containing TRAIL have lower viability than controls

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MHC class I-related chain A and MUC1 glycosylation is reduced in C2GnT KO cells

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Survival rate of nude mice inoculated with C2GnT KO tumors is higher than controls

Role of EIF4G1 network in non-small cell lung cancers (NSCLC) cell survival and disease progression

Although the Eukaryotic Translation Initiation Factor 4 Gamma 1 (EIF4G1) has been found overexpressed in a variety of cancers, its role in non–small cell lung cancers (NSCLC) pathogenesis especially in immunoregulatory functions, its clinical relevance and therapeutic potential remain largely unknown. By using cancer patients tissue assays, the results indicate that EIF4G1 expressional levels are much higher in NSCLC tissues than in adjacent or normal lung tissues, which are also associated with NSCLC patient survival. By using an RNA‐Sequencing based pipeline, the data show that EIF4G1 has a significant association with immune checkpoint molecules such as PD‐1/PD‐L1 in NSCLC. EIF4G1 small‐molecule inhibitors effectively repress NSCLC growth in cell culture and xenograft animal models. Protein array results identify the signature of proteins controlled by EIF4G1 in NSCLC cells, in which new candidates such as MUC1 and NRG1 are required for NSCLC survival and tumorigenesis with clinical relevance. Taken together, these results have for the first time demonstrated the immunoregulatory functions, clinical relevance and therapeutic potential of the EIF4G1 network in NSCLC, which may represent a promising and novel target to improve lung cancer treatment.

Role of the MUC1-C oncoprotein in the acquisition of cisplatin resistance by urothelial carcinoma

Mucin 1 C-terminal subunit (MUC1-C) has been introduced as a key regulator for acquiring drug resistance in various cancers, but the functional role of MUC1-C in urothelial carcinoma (UC) cells remains unknown. We aimed to elucidate the molecular mechanisms underlying the acquisition of cisplatin (CDDP) resistance through MUC1-C oncoprotein in UC cells. MUC1-C expression was examined immunohistochemically in tumor specimens of 159 UC patients who received CDDP-based perioperative chemotherapy. As a result, moderate to high MUC1-C expression was independently associated with poor survival in UC patients. Using human bladder cancer cell lines and CDDP-resistant (CR) cell lines, we compared the expression levels of MUC1-C, multiple drug resistance 1 (MDR1), the PI3K-AKT-mTOR pathway, and x-cystine/glutamate transporter (xCT) to elucidate the biological mechanisms contributing to the acquisition of chemoresistance. MUC1-C was strongly expressed in CR cell lines, followed with MDR1 expression via activation of the PI3K-AKT-mTOR pathway. MUC1-C also stabilized the expression of xCT, which enhanced antioxidant defenses by increasing intracellular glutathione (GSH) levels. MUC1 down-regulation showed MDR1 inhibition along with PI3K-AKT-mTOR pathway suppression. Moreover, it inhibited xCT stabilization and resulted in significant decreases in intracellular GSH levels and increased reactive oxygen species (ROS) generation. The MUC1-C inhibitor restored sensitivity to CDDP in CR cells and UC murine xenograft models. In conclusion, we found that MUC1-C plays a pivotal role in the acquisition of CDDP resistance in UC cells, and therefore the combined treatment of CDDP with a MUC1-C inhibitor may become a novel therapeutic option in CR UC patients.

A SERS-colorimetric dual-mode aptasensor for the detection of cancer biomarker MUC1

Human mucin-1 (MUC1) has attracted considerable attention owing to its overexpression in diverse malignancies. Here, for the rapid and efficient detection of MUC1, we present a SERS-colorimetric dual-mode aptasensor, by integrating SERS probes with magnetic separation, which has several distinctive advantages. Using such a dual-mode aptasensor, the colorimetric functionality is distinguishable by the naked eye, providing a fast and straightforward screening ability for the detection of MUC1. Moreover, SERS-based detection greatly improves the detection sensitivity, reaching a limit of detection of 0.1 U/mL. In addition, the combination of SERS and colorimetric method holds the advantages of these two techniques and thereby increases the reliability and efficiency of MUC1 detection. On the one hand, the magnetic nanobeads functionalized with MUC1-specific aptamer were utilized as an efficient capturing substrate for separating MUC1 from biological complex medium. On the other hand, the gold-silver core-shell nanoparticles modified with Raman reporters and the complementary sequences of MUC1 were used as the signal indicator, which could simultaneously report the SERS signal and colorimetric change. This strategy can achieve a good detection range and realize MUC1 analysis in real patients' samples. Thus, we anticipate that this kind of aptasensor would provide promising potential applications in the diagnosis and prognosis of cancers. Graphical abstract.

MiR-145: a potential biomarker of cancer migration and invasion

MircoRNAs (miRNAs) are a diverse family of highly-conserved small non-coding RNAs, which range from approximately 18 to 25 nucleotides in size. They regulate gene expression transcriptionally or post-transcriptionally via binding to the 3'-untranslated region (3'-UTR) of target message RNAs (mRNAs). MiRNAs have emerged as molecular regulators that participate in physiological and pathological processes of diverse malignancies. Among them, miRNA-145 (miR-145) played a profound role in tumorigenesis and progression of various neoplasms. In this review, we summarized the recent findings regarding miR-145, to elucidate its functional roles in cell invasion and migration of diverse human malignancies, and considered it a potential biomarker for cancer diagnosis, screening, and prognosis.

A Phase I Trial Using a Multitargeted Recombinant Adenovirus 5 (CEA/MUC1/Brachyury)-Based Immunotherapy Vaccine Regimen in Patients with Advanced Cancer

LESSONS LEARNED

Concurrent ETBX-011, ETBX-051, and ETBX-061 can be safely administered to patients with advanced cancer. All patients developed CD4⁺ and/or CD8⁺ T-cell responses after vaccination to at least one tumor-associated antigen (TAA) encoded by the vaccine; 5/6 patients (83%) developed MUC1-specific T cells, 4/6 (67%) developed CEA-specific T cells, and 3/6 (50%) developed brachyury-specific T cells. The presence of adenovirus 5-neutralizing antibodies did not prevent the generation of TAA-specific T cells.

BACKGROUND

A novel adenovirus-based vaccine targeting three human tumor-associated antigens-CEA, MUC1, and brachyury-has demonstrated antitumor cytolytic T-cell responses in preclinical animal models of cancer.

METHODS

This open-label, phase I trial evaluated concurrent administration of three therapeutic vaccines (ETBX-011 = CEA, ETBX-061 = MUC1 and ETBX-051 = brachyury). All three vaccines used the same modified adenovirus 5 (Ad5) vector backbone and were administered at a single dose level (DL) of 5 × 10¹¹ viral particles (VP) per vector. The vaccine regimen consisting of all three vaccines was given every 3 weeks for three doses then every 8 weeks for up to 1 year. Clinical and immune responses were evaluated.

RESULTS

Ten patients enrolled on trial (DL1 = 6 with 4 in the DL1 expansion cohort). All treatment-related adverse events were temporary, self-limiting, grade 1/2 and included injection site reactions and flu-like symptoms. Antigen-specific T cells to MUC1, CEA, and/or brachyury were generated in all patients. There was no evidence of antigenic competition. The administration of the vaccine regimen produced stable disease as the best clinical response.

CONCLUSION

Concurrent ETBX-011, ETBX-051, and ETBX-061 can be safely administered to patients with advanced cancer. Further studies of the vaccine regimen in combination with other agents, including immune checkpoint blockade, are planned.

A Phase I Dose-Escalation Trial of BN-CV301, a Recombinant Poxviral Vaccine Targeting MUC1 and CEA with Costimulatory Molecules

PURPOSE

BN-CV301 is a poxviral-based vaccine comprised of recombinant (rec.) modified vaccinia Ankara (MVA-BN-CV301; prime) and rec. fowlpox (FPV-CV301; boost). Like its predecessor PANVAC, BN-CV301 contains transgenes encoding tumor-associated antigens MUC1 and CEA as well as costimulatory molecules (B7.1, ICAM-1, and LFA-3). PANVAC was reengineered to make it safer and more antigenic.

PATIENTS AND METHODS

This open-label, 3+3 design, dose-escalation trial evaluated three dose levels (DL) of MVA-BN-CV301: one, two, or four subcutaneous injections of 4 × 10⁸ infectious units (Inf.U)/0.5 mL on weeks 0 and 4. All patients received FPV-CV301 subcutaneously at 1 × 10⁹ Inf.U/0.5 mL every 2 weeks for 4 doses, then every 4 weeks. Clinical and immune responses were evaluated.

RESULTS

There were no dose-limiting toxicities. Twelve patients enrolled on trial [dose level (DL) 1 = 3, DL2 = 3, DL3 = 6). Most side effects were seen with the prime doses and lessened with subsequent boosters. All treatment-related adverse events were temporary, self-limiting, grade 1/2, and included injection-site reactions and flu-like symptoms. Antigen-specific T cells to MUC1 and CEA, as well as to a cascade antigen, brachyury, were generated in most patients. Single-agent BN-CV301 produced a confirmed partial response (PR) in 1 patient and prolonged stable disease (SD) in multiple patients, most notably in KRAS-mutant gastrointestinal tumors. Furthermore, 2 patients with KRAS-mutant colorectal cancer had prolonged SD when treated with an anti-PD-L1 antibody following BN-CV301.

CONCLUSIONS

The BN-CV301 vaccine can be safely administered to patients with advanced cancer. Further studies of the vaccine in combination with other agents are planned.See related commentary by Repáraz et al., p. 4871.

Interaction Between MUC1 and STAT1 Drives IFITM1 Overexpression in Aromatase Inhibitor-Resistant Breast Cancer Cells and Mediates Estrogen-Induced Apoptosis

The human oncoprotein, mucin 1 (MUC1), drives tumorigenesis in breast carcinomas by promoting epithelial-to-mesenchymal transition (EMT), epigenetic reprogramming, and evasion of immune response. MUC1 interacts with STAT1, through JAK/STAT signaling, and stimulates transcription of IFN-stimulated genes, specifically IFN-induced transmembrane protein 1 (IFITM1). Our laboratory has previously shown that IFITM1 overexpression in aromatase inhibitor (AI)-resistant breast cancer cells promotes aggressiveness. Here, we demonstrate that differential regulation of MUC1 in AI-sensitive (MCF-7 and T-47D) compared with AI-resistant (MCF-7:5C) cells is critical in mediating IFITM1 expression. A tumor microarray of 94 estrogen receptor-positive human breast tumors correlated coexpression of MUC1 and IFITM1 with poor recurrence-free survival, poor overall survival, and AI-resistance. In this study, we investigated the effects of MUC1/IFITM1 on cell survival and proliferation. We knocked down MUC1 levels with siRNA and pharmacologic inhibitors, which abrogated IFITM1 mRNA and protein expression and induced cell death in AI-resistant cells. In vivo, estrogen and ruxolitinib significantly reduced tumor size and decreased expression of MUC1, P-STAT1, and IFITM1. IMPLICATIONS: MUC1 and IFITM1 overexpression drives AI resistance and can be targeted with currently available therapies.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/5/1180/F1.large.jpg.

Anti-KL-6/MUC1 monoclonal antibody reverses resistance to trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity by capping MUC1

Polymorphic epithelial mucin (MUC1) is generally overexpressed on the surface of most adenocarcinomas including breast cancer. MUC1 is associated with chemotherapeutic resistance and immune evasion of cancer cells; however, the association between MUC1 and trastuzumab-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) remains unclear. In this study, using six breast cancer cell lines with differing expression levels and MUC1 distribution, the present results show that cells with MUC1 overexpression and uniform surface distribution were resistant to trastuzumab-mediated ADCC. Importantly, trastuzumab resistance was reversed upon siRNA-mediated MUC1 knockdown and by using anti-KL-6/MUC1 monoclonal antibody (mAb). Additionally, we visually confirmed that anti-KL-6/MUC1 mAb induced capping of MUC1 molecules on the cell surface, resulting the in death of these cells. These results suggest that not only the quantity but also the cell-surface distribution of MUC1 affects the sensitivity of breast cancer cells to trastuzumab-mediated ADCC.

Targeting the human MUC1-C oncoprotein with an antibody-drug conjugate

Mucin 1 (MUC1) is a heterodimeric protein that is aberrantly overexpressed on the surface of diverse human carcinomas and is an attractive target for the development of mAb-based therapeutics. However, attempts at targeting the shed MUC1 N-terminal subunit have been unsuccessful. We report here the generation of mAb 3D1 against the nonshed oncogenic MUC1 C-terminal (MUC1-C) subunit. We show that mAb 3D1 binds with low nM affinity to the MUC1-C extracellular domain at the restricted α3 helix. mAb 3D1 reactivity is selective for MUC1-C-expressing human cancer cell lines and primary cancer cells. Internalization of mAb 3D1 into cancer cells further supported the conjugation of mAb 3D1 to monomethyl auristatin E (MMAE). The mAb 3D1-MMAE antibody-drug conjugate (ADC) (a) kills MUC1-C-positive cells in vitro, (b) is nontoxic in MUC1-transgenic (MUC1.Tg) mice, and (c) is active against human HCC827 lung tumor xenografts. Humanized mAb (humAb) 3D1 conjugated to MMAE also exhibited antitumor activity in (a) MUC1.Tg mice harboring syngeneic MC-38/MUC1 tumors, (b) nude mice bearing human ZR-75-1 breast tumors, and (c) NCG mice engrafted with a patient-derived triple-negative breast cancer. These findings and the absence of associated toxicities support clinical development of humAb 3D1-MMAE ADCs as a therapeutic for the many cancers with MUC1-C overexpression.

MUC1-C activates polycomb repressive complexes and downregulates tumor suppressor genes in human cancer cells

The PRC2 and PRC1 complexes are aberrantly expressed in human cancers and have been linked to decreases in patient survival. MUC1-C is an oncoprotein that is also overexpressed in diverse human cancers and is associated with a poor prognosis. Recent studies have supported a previously unreported function for MUC1-C in activating PRC2 and PRC1 in cancer cells. In the regulation of PRC2, MUC1-C (i) drives transcription of the EZH2 gene, (ii) binds directly to EZH2, and (iii) enhances occupancy of EZH2 on target gene promoters with an increase in H3K27 trimethylation. Regarding PRC1, which is recruited to PRC2 sites in the hierarchical model, MUC1-C induces BMI1 transcription, forms a complex with BMI1, and promotes H2A ubiquitylation. MUC1-C thereby contributes to the integration of PRC2 and PRC1-mediated repression of tumor suppressor genes, such as CDH1, CDKN2A, PTEN and BRCA1. Like PRC2 and PRC1, MUC1-C is associated with the epithelial-mesenchymal transition (EMT) program, cancer stem cell (CSC) state, and acquisition of anticancer drug resistance. In concert with these observations, targeting MUC1-C downregulates EZH2 and BMI1, inhibits EMT and the CSC state, and reverses drug resistance. These findings emphasize the significance of MUC1-C as a therapeutic target for inhibiting aberrant PRC function and reprogramming the epigenome in human cancers.

Glycosylation Changes in Brain Cancer

Protein glycosylation is a posttranslational modification that affects more than half of all known proteins. Glycans covalently bound to biomolecules modulate their functions by both direct interactions, such as the recognition of glycan structures by binding partners, and indirect mechanisms that contribute to the control of protein conformation, stability, and turnover. The focus of this Review is the discussion of aberrant glycosylation related to brain cancer. Altered sialylation and fucosylation of N- and O-glycans play a role in the development and progression of brain cancer. Additionally, aberrant O-glycan expression has been implicated in brain cancer. This Review also addresses the clinical potential and applications of aberrant glycosylation for the detection and treatment of brain cancer. The viable roles glycans may play in the development of brain cancer therapeutics are addressed as well as cancer-glycoproteomics and personalized medicine. Glycoprotein alterations are considered as a hallmark of cancer while high expression in body fluids represents an opportunity for cancer assessment.

Fluorescence Sensing Using DNA Aptamers in Cancer Research and Clinical Diagnostics

Among the various advantages of aptamers over antibodies, remarkable is their ability to tolerate a large number of chemical modifications within their backbone or at the termini without losing significant activity. Indeed, aptamers can be easily equipped with a wide variety of reporter groups or coupled to different carriers, nanoparticles, or other biomolecules, thus producing valuable molecular recognition tools effective for diagnostic and therapeutic purposes. This review reports an updated overview on fluorescent DNA aptamers, designed to recognize significant cancer biomarkers both in soluble or membrane-bound form. In many examples, the aptamer secondary structure switches induced by target recognition are suitably translated in a detectable fluorescent signal using either fluorescently-labelled or label-free aptamers. The fluorescence emission changes, producing an enhancement (“signal-on”) or a quenching (“signal-off”) effect, directly reflect the extent of the binding, thereby allowing for quantitative determination of the target in bioanalytical assays. Furthermore, several aptamers conjugated to fluorescent probes proved to be effective for applications in tumour diagnosis and intraoperative surgery, producing tumour-type specific, non-invasive in vivo imaging tools for cancer pre- and post-treatment assessment.

MUC1 induces M2 type macrophage influx during postpartum mammary gland involution and triggers breast cancer

The microenvironment of postpartum mammary gland involution (PMI) has been linked to the increased risk of breast cancer and poor outcome of patients. Nevertheless the mechanism underlying regulates the microenvironment remains largely unknown. MUC1, which is abnormally overexpressed in most breast cancer, is physiologically expressed in PMI. Using MUC1 cytoplasm domain (MUC1-CD) transgenic mice, we reveal that the overexpression of MUC1-CD in mammary epithelial cells increases M2 type macrophage infiltration in PMI. By sustain activating p50, MUC1 upregulates M2 macrophage chemo-attractants and the anti-apoptotic protein Bcl-xL. Because of the tumor promotional microenvironments and reduced apoptosis, MUC1-CD delays PMI process and results in atypical phenotype in multiparous mice mammary. This finding is further supported by the positive association between the expression of MUC1 and p50 in Luminal A and Luminal B subtypes through analyzing breast cancer databases. Taken together, our study demonstrates that MUC1-CD plays an important role in regulating microenvironment of PMI and promoting postpartum mammary tumorigenicity, providing novel prevention and treatment strategies against postpartum breast cancer.

Functional interactions of the cystine/glutamate antiporter, CD44v and MUC1-C oncoprotein in triple-negative breast cancer cells

The xCT light chain of the cystine/glutamate transporter (system X_C⁻) is of importance for the survival of triple-negative breast cancer (TNBC) cells. The MUC1-C transmembrane oncoprotein is aberrantly overexpressed in TNBC and, like xCT, has been linked to maintaining glutathione (GSH) levels and redox balance. However, there is no known interaction between MUC1-C and xCT. Here we show that silencing MUC1-C is associated with decreases in xCT expression in TNBC cells. The results demonstrate that MUC1-C forms a complex with xCT and the CD44 variant (CD44v), which interacts with xCT and thereby controls GSH levels. MUC1-C binds directly with CD44v and in turn promotes stability of xCT in the cell membrane. The interaction between MUC1-C and xCT is further supported by the demonstration that targeting xCT with silencing or the inhibitor sulfasalazine suppresses MUC1 gene transcription by increasing histone and DNA methylation on the MUC1 promoter. In terms of the functional significance of the MUC1-C/xCT interaction, we show that MUC1-C protects against treatment with erastin, an inhibitor of X_C⁻ and inducer of ferroptosis, a form of non-apoptotic cell death. These findings indicate that targeting this novel MUC1-C/xCT pathway could represent a potential therapeutic approach for promoting TNBC cell death.

MUC1: The First Respiratory Mucin with an Anti-Inflammatory Function

MUC1 is a membrane-bound mucin expressed on the apical surfaces of most mucosal epithelial cells. In normal lung epithelia, MUC1 is a binding site for Pseudomonas aeruginosa, an opportunistic human pathogen of great clinical importance. It has now been established that MUC1 also serves an anti-inflammatory role in the airways that is initiated late in the course of a bacterial infection and is mediated through inhibition of Toll-like receptor (TLR) signaling. MUC1 expression was initially shown to interfere with TLR5 signaling in response to P. aeruginosa flagellin, but has since been extended to other TLRs. These new findings point to an immunomodulatory role for MUC1 during P. aeruginosa lung infection, particularly during the resolution phase of inflammation. This review briefly summarizes the recent characterization of MUC1’s anti-inflammatory properties in both the respiratory tract and extrapulmonary tissues.

MUC1 induces acquired chemoresistance by upregulating ABCB1 in EGFR-dependent manner

Chemoresistance contributes to cancer relapse and increased mortality in a variety of cancer types, raising a pressing need to better understand the underlying mechanism. MUC1 is abnormally overexpressed in numerous carcinomas and associated with poor prognosis. However, the functional significance of MUC1 in chemoresistance has not been fully elucidated. Here, we showed that MUC1 expression was considerably induced in cells that had acquired chemoresistance at both transcriptional and post-translational levels. Using gain- and loss-of function approaches, we demonstrated a critical role of MUC1 in induction of drug resistance. Through stimulation of EGFR activation and nuclear translocation, MUC1 increased the expression of ATP-binding cassette transporter B1 (ABCB1). Remarkably, targeted suppression of EGFR or ABCB1 by both shRNAs and inhibitors effectively reversed chemoresistance. Moreover, co-administration of the inhibitors of MUC1-EGFR-ABCB1 with paclitaxel significantly blocked not only tumor growth but also relapse in xenograft mouse model. Our data collectively support a model in which MUC1 induces acquired chemotherapy resistance by upregulating ABCB1 in an EGFR-dependent manner, providing a novel molecular basis of using the EGFR inhibitor in MUC1-positive cancers to prevent chemotherapy resistance.

MUC1 overexpression predicts worse survival in patients with non-small cell lung cancer: evidence from an updated meta-analysis

Background

Previous studies on the prognostic role of MUC1 expression in non-small cell lung cancer (NSCLC) remain controversial. We conducted a meta-analysis to appraise the clinicopathological and prognostic effect of MUC1 in NSCLC patients.

Materials and Methods

Searches of PubMed, EMBASE and CNKI (Chinese National Knowledge Infrastructure) were conducted and relevant studies were extracted. The pooled hazard ratio (HR) or odds ratio (OR) with 95% confidence intervals (CIs) were used to estimate effects. Heterogeneity among studies and publication bias were also evaluated.

Results

A total of 15 studies with 1,682 patients were included in this meta-analysis. The pooled HRs indicated that elevated MUC1 expression was associated with poorer overall survival (HR = 2.12, 95% CI: 1.47–3.05; P < 0.001) and progression-free survival (HR = 2.00, 95% CI: 1.53-2.62; P < 0.001) in patients with NSCLC. Significant associations were also found in patients treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) (HR = 3.16, 95% CI: 2.21–4.52, P < 0.001) and with a platinum-based regimen (HR = 4.35, 95% CI: 2.45–7.72, P < 0.001). Additionally, MUC1 overexpression was significantly associated with performance status (OR = 2.32, 95% CI: 1.13–4.73, P = 0.021).

Conclusions

MUC1 could be a valuable biomarker of the prognoses of NSCLC patients.

MUC1-C promotes the suppressive immune microenvironment in non-small cell lung cancer

The cancer immune microenvironment is of importance for the effectiveness of immunotherapy; however, its dysregulation is poorly understood. The MUC1-C oncoprotein is aberrantly overexpressed in non-small cell lung cancer (NSCLC) and has been linked to the induction of PD-L1. The present work investigated the effects of targeting MUC1-C in an immuno-competent MUC1 transgenic (MUC1.Tg) mouse model. We show that Lewis Lung Carcinoma cells expressing MUC1-C (LLC/MUC1) exhibit upregulation of PD-L1 and suppression of interferon-γ (IFN-γ). In studies of LLC/MUC1 cells growing in vitro and as tumors in MUC1.Tg mice, treatment with the MUC1-C inhibitor, GO-203, was associated with the downregulation of PD-L1 and induction of IFN-γ. The results further demonstrate that targeting MUC1-C results in enhanced effector function of CD8+ tumor-infiltrating lymphocytes (TILs) as evidenced by increased expression of the activation marker CD69, the degranulation marker CD107α, and granzyme B. Notably, targeting MUC1-C was also associated with marked increases in TIL-mediated killing of LLC/MUC1 cells. Analysis of gene expression data sets further showed that overexpression of MUC1 in NSCLCs correlates negatively with CD8, IFNG and GZMB, and that decreases in CD8 and IFNG are associated with poor clinical outcomes. These findings in LLC/MUC1 tumors and in NSCLCs indicate that MUC1-C→PD-L1 signaling promotes the suppression of CD8+ T-cell activation and that MUC1-C is a potential target for reprogramming of the tumor microenvironment.

Mucoepidermoid carcinoma-associated expression of MUC5AC, MUC5B and mucin-type carbohydrate antigen sialyl-Tn in the parotid gland

OBJECTIVES

The aberrant expression of mucins and mucin-type carbohydrates has been described in many types of cancer, including mucoepidermoid carcinoma (MEC), a malignant salivary gland tumor. In this study, we examined the aberrant expression patterns of mucins (MUC1, MUC4, MUC5AC and MUC5B), simple mucin-type carbohydrate antigens (Tn, sialyl-Tn and T) and mature carbohydrate antigens (Lewis^a and sulfo-Lewis^a antigens) in MEC originating from the parotid gland, which normally does not secrete mucins.

DESIGN

We conducted an immunohistochemical study to investigate the presence of mucins and carbohydrates in 24 MEC samples originating from the parotid gland and in surrounding normal tissue of the same gland in comparison 6 samples of normal salivary glands. The expression levels were compared with respect to the histological grading. Furthermore, 24 MEC samples from non-parotid salivary glands were included.

RESULTS

We observed loss of topology of membrane-bound MUC1 and MUC4, and de novo expression of MUC5AC, MUC5B and sialyl-Tn in MEC that originated in the parotid gland. Furthermore, mucins MUC1, MUC4 and carbohydrate antigens Tn, sialyl-Tn, T, Lewis^a and sulfo-Lewis^a were overexpressed in MEC samples compared to surrounding normal salivary gland tissues. MUC1 was expressed in both low- and high grade MECs, whereas MUC4 was not expressed in high grade MECs of the parotid gland.

CONCLUSION

During the development of MEC in the parotid gland, the genes for gel-forming secretory mucins are switched on. Besides these MEC tissues overexpress short oligosaccharides, suggesting that the glycosylation machinery is altered.

Lewis(y) antigen promotes the progression of epithelial ovarian cancer by stimulating MUC1 expression

MUC1 is a type I transmembrane glycoprotein and is overexpressed in various epithelial tumor tissues. Some researchers have demonstrated that the glycosylation status of MUC1 can affect MUC1-mediated tumor growth and cell differentiation. In our previous study, we proved that the abilities of cell proliferation, adhesion, invasion and metastasis, and drug resistance were enhanced in ovarian cancer cells stably expressing Lewis(y). Therefore, we hypothesized that Lewis(y) antigen may play a central role in regulating MUC1 expression, and MUC1-mediated cell growth and differentiation may be closely associated with Lewis(y) antigen. This study aimed to examine the correlation between MUC1 expression and Lewis(y) antigen levels in ovarian cancer cell lines and tissue samples. A series of techniques, including RT-qPCR, western blot anlaysis, immunoprecipitation, immunohistochemistry and double-labeling immunofluorescence were applied to detect the expression of Lewis(y) and MUC1. In malignant epithelial ovarian tumors, the positive expression rates of Lewis(y) antigen and MUC1 were 88.33 and 86.67%, respectively, which were markedly higher than those in borderline (60.00 and 53.33%, P<0.05), benign (33.33 and 30%, P<0.01) and normal (0 and 25%, P<0.01) ovarian samples. There was no correlation between the positive expression rates of Lewis(y) or MUC1 and clinicopathological parameters in ovarian cancers (P>0.05). The expression levels of Lewis(y) and MUC1 correlated with the clinical FIGO stage (P<0.05). Both MUC1 and Lewis(y) were highly expressed in ovarian cancer tissues, and their expression levels were positively correlated (P<0.01). In α1,2-fucosyltransferase (α1,2-FT)-transfected cells, the gene and protein expression levels of MUC1 were significantly upregulated compared with the cells that did not overexpress α1,2-FT (P<0.05). The ratio of Lewis(y) immunoprecipitated with MUC1 to total MUC1 increased 1.55-fold in α1,2-FT-overexpressing cells (P<0.05). The overexpression of Lewis(y) resulted in the upregulation of MUC1. On the whole, our data indicate that both MUC1 and Lewis(y) are associated with the occurrence and development of ovarian cancers.

Molecular Pathways: Mucins and Drug Delivery in Cancer

Over the past few decades, clinical and preclinical studies have clearly demonstrated the role of mucins in tumor development. It is well established that mucins form a barrier impeding drug access to target sites, leading to cancer chemoresistance. Recently gained knowledge regarding core enzyme synthesis has opened avenues to explore the possibility of disrupting mucin synthesis to improve drug efficacy. Cancer cells exploit aberrant mucin synthesis to efficiently mask the epithelial cells and ensure survival under hostile tumor microenvironment conditions. However, O-glycan synthesis enzyme core 2 beta 1,6 N-acetylglucosaminyltransferase (GCNT3/C2GnT-2) is overexpressed in Kras-driven mouse and human cancer, and inhibition of GCNT3 has been shown to disrupt mucin synthesis. This previously unrecognized developmental pathway might be responsible for aberrant mucin biosynthesis and chemoresistance. In this Molecular Pathways article, we briefly discuss the potential role of mucin synthesis in cancers, ways to improve drug delivery and disrupt mucin mesh to overcome chemoresistance by targeting mucin synthesis, and the unique opportunity to target the GCNT3 pathway for the prevention and treatment of cancers. Clin Cancer Res; 23(6); 1373-8. ©2016 AACR.

MUC1-C integrates PD-L1 induction with repression of immune effectors in non-small-cell lung cancer

Immunotherapeutic approaches, particularly PD-1/PD-L1 blockade, have improved the treatment of non-small cell lung cancer (NSCLC), supporting the premise that evasion of immune destruction is of importance for NSCLC progression. However, the signals responsible for upregulation of PD-L1 in NSCLC cells and whether they are integrated with the regulation of other immune-related genes are not known. Mucin 1 (MUC1) is aberrantly overexpressed in NSCLC, activates the NF-κB p65→ZEB1 pathway and confers a poor prognosis. The present studies demonstrate that MUC1-C activates PD-L1 expression in NSCLC cells. We show that MUC1-C increases NF-κB p65 occupancy on the CD274/PD-L1 promoter and thereby drives CD274 transcription. Moreover, we demonstrate that MUC1-C-induced activation of NF-κB→ZEB1 signaling represses the TLR9, IFNG, MCP-1 and GM-CSF genes, and that this signature is associated with decreases in overall survival. In concert with these results, targeting MUC1-C in NSCLC tumors suppresses PD-L1 and induces these effectors of innate and adaptive immunity. These findings support a previously unrecognized central role for MUC1-C in integrating PD-L1 activation with suppression of immune effectors and poor clinical outcome.

The generation and analyses of a novel combination of recombinant adenovirus vaccines targeting three tumor antigens as an immunotherapeutic

Phenotypic heterogeneity of human carcinoma lesions, including heterogeneity in expression of tumor-associated antigens (TAAs), is a well-established phenomenon. Carcinoembryonic antigen (CEA), MUC1, and brachyury are diverse TAAs, each of which is expressed on a wide range of human tumors. We have previously reported on a novel adenovirus serotype 5 (Ad5) vector gene delivery platform (Ad5 [E1-, E2b-]) in which regions of the early 1 (E1), early 2 (E2b), and early 3 (E3) genes have been deleted. The unique deletions in this platform result in a dramatic decrease in late gene expression, leading to a marked reduction in host immune response to the vector. Ad5 [E1-, E2b-]-CEA vaccine (ETBX-011) has been employed in clinical studies as an active vaccine to induce immune responses to CEA in metastatic colorectal cancer patients. We report here the development of novel recombinant Ad5 [E1-, E2b-]-brachyury and-MUC1 vaccine constructs, each capable of activating antigen-specific human T cells in vitro and inducing antigen-specific CD4⁺ and CD8⁺ T cells in vaccinated mice. We also describe the use of a combination of the three vaccines (designated Tri-Ad5) of Ad5 [E1-, E2b-]-CEA, Ad5 [E1-, E2b-]-brachyury and Ad5 [E1-, E2b-]-MUC1, and demonstrate that there is minimal to no “antigenic competition” in in vitro studies of human dendritic cells, or in murine vaccination studies. The studies reported herein support the rationale for the application of Tri-Ad5 as a therapeutic modality to induce immune responses to a diverse range of human TAAs for potential clinical studies.

Downregulation of lysosomal and further gene expression characterization in lung cancer patients with bone metastasis

Molecular and functional mechanisms of bone metastases were poorly understood. This study was to screen out differentially expressed genes (DEGs) and functional proteins in bone metastases from lung for better understanding of the molecular and functional mechanisms. Our results suggested CTSS, CTSD, MX1, NKX2-1 might play a decisive role in bone metastasis. Collectively, these results demonstrated that bone metastasis from lung cancer would lead to changes in lysosome function, which may affect the decomposition and elimination of old bone matrix, thus affecting bone turnover. In addition, our findings provided new insights into the prediction and treatment of bone metastases.

Inhibition of MUC1-C Suppresses MYC Expression and Attenuates Malignant Growth in KRAS Mutant Lung Adenocarcinomas

Dysregulation of MYC expression is a hallmark of cancer, but the development of agents that target MYC has remained challenging. The oncogenic MUC1-C transmembrane protein is, like MYC, aberrantly expressed in diverse human cancers. The present studies demonstrate that MUC1-C induces MYC expression in KRAS mutant non-small cell lung cancer (NSCLC) cells, an effect that can be suppressed by targeting MUC1-C via shRNA silencing, CRISPR editing, or pharmacologic inhibition with GO-203. MUC1-C activated the WNT/β-catenin (CTNNB1) pathway and promoted occupancy of MUC1-C/β-catenin/TCF4 complexes on the MYC promoter. MUC1-C also promoted the recruitment of the p300 histone acetylase (EP300) and, in turn, induced histone H3 acetylation and activation of MYC gene transcription. We also show that targeting MUC1-C decreased the expression of key MYC target genes essential for the growth and survival of NSCLC cells, such as TERT and CDK4. Based on these results, we found that the combination of GO-203 and the BET bromodomain inhibitor JQ1, which targets MYC transcription, synergistically suppressed MYC expression and cell survival in vitro as well as tumor xenograft growth. Furthermore, MUC1 expression significantly correlated with that of MYC and its target genes in human KRAS mutant NSCLC tumors. Taken together, these findings suggest a therapeutic approach for targeting MYC-dependent cancers and provide the framework for the ongoing clinical studies addressing the efficacy of MUC1-C inhibition in solid tumors.

MUC5AC interactions with integrin β4 enhances the migration of lung cancer cells through FAK signaling

MUC5AC is a secretory mucin aberrantly expressed in various cancers. In lung cancer, MUC5AC is overexpressed in both primary and metastatic lesions; however, its functional role is not well understood. The present study was aimed at evaluating mechanistic role of MUC5AC on metastasis of lung cancer cells. Clinically, the overexpression of MUC5AC was observed in lung cancer patient tissues and was associated with poor survival. In addition, the overexpression of Muc5ac was also observed in genetically engineered mouse lung adenocarcinoma tissues (Kras(G12D); Trp53(R172H/+); AdCre) in comparison with normal lung tissues. Our functional studies showed that MUC5AC knockdown resulted in significantly decreased migration in two lung cancer cell lines (A549 and H1437) as compared with scramble cells. Expression of integrins (α5, β1, β3, β4 and β5) was decreased in MUC5AC knockdown cells. As both integrins and MUC5AC have a von Willebrand factor domain, we assessed for possible interaction of MUC5AC and integrins in lung cancer cells. MUC5AC strongly interacted only with integrin β4. The co-localization of MUC5AC and integrin β4 was observed both in A549 lung cancer cells as well as genetically engineered mouse adenocarcinoma tissues. Activated integrins recruit focal adhesion kinase (FAK) that mediates metastatic downstream signaling pathways. Phosphorylation of FAK (Y397) was decreased in MUC5AC knockdown cells. MUC5AC/integrin β4/FAK-mediated lung cancer cell migration was confirmed through experiments utilizing a phosphorylation (Y397)-specific FAK inhibitor. In conclusion, overexpression of MUC5AC is a poor prognostic marker in lung cancer. MUC5AC interacts with integrin β4 that mediates phosphorylation of FAK at Y397 leading to lung cancer cell migration.

Mucins in lung cancer: diagnostic, prognostic, and therapeutic implications

Aberrant expression of mucins is associated with cancer development and metastasis. An overexpression of few mucins contributes to oncogenesis by enhancing cancer cell growth and providing constitutive survival signals. This review focuses on the importance of mucins both in the normal bronchial epithelial cells and the malignant tumors of the lung and their contribution in the diagnosis and prognosis of lung cancer patients. During lung cancer progression, mucins either alone or through their interaction with many receptor tyrosine kinases mediate cell signals for growth and survival of cancer cells. Also, stage-specific expression of certain mucins, like MUC1, is associated with poor prognosis from lung cancer. Thus, mucins are emerging as attractive targets for developing novel therapeutic approaches for lung cancer. Several strategies targeting mucin expression and function are currently being investigated to control lung cancer progression.

Update on Mucin-1 immunotherapy in cancer: a clinical perspective

INTRODUCTION

Mucin 1 (MUC1) is particularly well suited as a cancer immunotherapy target due to the elevated protein expression and aberrant forms associated with malignancy. A variety of therapeutic strategies have been explored, including antibodies intended to induce cancer cell destruction, and vaccinations with peptides, tumor extracts, and gene expression systems.

AREAS COVERED

MUC1 immunotherapeutic strategies have included vaccination with peptide sequences, glycan molecules, viruses, and dendritic cells, monoclonal antibodies and monoclonal antibody conjugates. Here we review the relevant clinical trials in each field of immunotherapy with particular focus on large and recently published trials.

EXPERT OPINION

Long clinical experience in the trial setting has reduced concerns of immunotherapy associated toxicities and inappropriate immune responses, with the main limitation (common to many experimental approaches) being a lack of clinical efficacy. However, there have been sufficient treatment-associated responses to justify continued pursuit of MUC1 targeted immunotherapies. The focus now should be on application to the relevant cancers under appropriate circumstances and combination with the emerging non-specific immunotherapy approaches such as the PD-1 pathway inhibitors.

MUC1-C confers EMT and KRAS independence in mutant KRAS lung cancer cells

Non-small cell lung cancers (NSCLCs) that harbor an oncogenic KRAS mutation are often associated with resistance to targeted therapies. The MUC1-C transmembrane protein is aberrantly overexpressed in NSCLCs and confers a poor outcome; however, the functional role for MUC1-C in mutant KRAS NSCLC cells has remained unclear. The present studies demonstrate that silencing MUC1-C in A549/KRAS(G12S) and H460/KRAS(Q61H) NSCLC cells is associated with downregulation of AKT signaling and inhibition of growth. Overexpression of a MUC1-C(CQC→AQA) mutant, which inhibits MUC1-C homodimerization and function, suppressed both AKT and MEK activation. Moreover, treatment with GO-203, an inhibitor of MUC1-C homodimerization, blocked AKT and MEK signaling and decreased cell survival. The results further demonstrate that targeting MUC1-C suppresses expression of the ZEB1 transcriptional repressor by an AKT-mediated mechanism, and in turn induces miR-200c. In concert with these effects on the ZEB1/miR-200c regulatory loop, targeting MUC1-C was associated with reversal of the epithelial-mesenchymal transition (EMT) and inhibition of self-renewal capacity. Loss of MUC1-C function also attenuated KRAS independence and inhibited growth of KRAS mutant NSCLC cells as tumors in mice. These findings support a model in which targeting MUC1-C inhibits mutant KRAS signaling in NSCLC cells and thereby reverses the EMT phenotype and decreases self-renewal.

Establishment of a heterotypic 3D culture system to evaluate the interaction of TREG lymphocytes and NK cells with breast cancer

Three-dimensional (3D) culture approaches to investigate breast tumour progression are yielding information more reminiscent of the in vivo microenvironment. We have established a 3D Matrigel system to determine the interactions of luminal phenotype MCF-7 cells and basal phenotype MDA-MB-231 cells with regulatory T lymphocytes and Natural Killer cells. Immune cells were isolated from peripheral blood using magnetic cell sorting and their phenotype validated using flow cytometry both before and after activation with IL-2 and phytohaemagglutinin. Following the establishment of the heterotypic culture system, tumour cells displayed morphologies and cell-cell associations distinct to that observed in 2D monolayer cultures, and associated with tissue remodelling and invasion processes. We found that the level of CCL4 secretion was influenced by breast cancer phenotype and immune stimulation. We further established that for RNA extraction, the use of proteinase K in conjunction with the Qiagen RNeasy Mini Kit and only off-column DNA digestion gave the best RNA yield, purity and integrity. We also investigated the efficacy of the culture system for immunolocalisation of the biomarkers oestrogen receptor-α and the glycoprotein mucin 1 in luminal phenotype breast cancer cells; and epidermal growth factor receptor in basal phenotype breast cancer cells, in formalin-fixed, paraffin-wax embedded cultures. The expression of these markers was shown to vary under immune mediation. We thus demonstrate the feasibility of using this co-culture system for downstream applications including cytokine analysis, immunolocalisation of tumour biomarkers on serial sections and RNA extraction in accordance with MIQE guidelines.

Microenvironment, tumor cell plasticity, and cancer

PURPOSE OF REVIEW

Much effort has been devoted to determining how cellular and noncellular components of the tumoral niche initiate and promote cancer development. Cancer cells perceive biochemical signals from components of the extracellular matrix (ECM) and sense physical features, such as matrix stiffness and cell confinement. The past decade has seen a better understanding of the biophysics and mechanobiology associated with cancer cells. Indeed, loss of mechanisms controlling the production, the degradation, and the remodeling of ECM contributes to tumor growth or cell dissemination by affecting cell contractility in response to ECM stiffness and by stimulating mechanical dependence of growth factor activation.

RESULTS

Cell plasticity allows adaptative strategies for cancer cells to survive or eventually escape from tumoral environment through modification of the microenvironment-cell interface, internal tension increase, and nuclear deformation partly leading to intratumoral heterogeneity. However, although alteration of the biomechanical properties of the ECM are sufficient to promote cell migration and invasion in cancer cells, this microenvironment can also provide a hospitable niche for tumor dormancy and resistance to cancer therapy.

CONCLUSION

The review will focus on how physicochemical properties of ECM might promote tumor growth or cell dissemination or on the contrary maintain quiescent state of cancer cells. It is crucial to clarify the molecular basis of mechanotransduction in the development and progression of tumors to identify new potential biomarkers and anticancer therapeutic targets.

Oncogenic CXCL10 signalling drives metastasis development and poor clinical outcome

Background:

The CXCL10/CXCR3 signalling mediates paracrine interactions between tumour and stromal cells that govern leukocyte trafficking and angiogenesis. Emerging data implicate noncanonical CXCL10/CXCR3 signalling in tumourigenesis and metastasis. However, little is known regarding the role for autocrine CXCL10/CXCR3 signalling in regulating the metastatic potential of individual tumour clones.

Methods:

We performed transcriptomic and cytokine profiling to characterise the functions of CXCL10 and CXCR3 in tumour cells with different metastatic abilities. We modulated the expression of the CXCL10/CXCR3 pathway using shRNA-mediated silencing in both in vitro and in vivo models of B16F1 melanoma. In addition, we examined the expression of CXCL10 and CXCR3 and their associations with clinical outcomes in clinical data sets derived from over 670 patients with melanoma and colon and renal cell carcinomas.

Results:

We identified a critical role for autocrine CXCL10/CXCR3 signalling in promoting tumour cell growth, motility and metastasis. Analysis of publicly available clinical data sets demonstrated that coexpression of CXCL10 and CXCR3 predicted an increased metastatic potential and was associated with early metastatic disease progression and poor overall survival.

Conclusion:

These findings support the potential for CXCL10/CXCR3 coexpression as a predictor of metastatic recurrence and point towards a role for targeting of this oncogenic axis in the treatment of metastatic disease.

Low miR-145 silenced by DNA methylation promotes NSCLC cell proliferation, migration and invasion by targeting mucin 1

MiR-145 has been implicated in the progression of non-small cell lung cancer (NSCLC); however, its exact mechanism is not well established. Here, we report that miR-145 expression is decreased in NSCLC cell lines and tumor tissues and that this low level of expression is associated with DNA methylation. MiR-145 methylation in NSCLC was correlated with a more aggressive tumor phenotype and was associated with poor survival time, as shown by Kaplan-Meier analysis. Additional multivariate Cox regression analysis indicated that miR-145 methylation was an independent prognostic factor for poor survival in patients with NSCLC. Furthermore, we found that restoration of miR-145 expression inhibited proliferation, migration and invasion of NSCLC by the direct targeting of mucin 1 by miR-145. Our results indicate that low miR-145 expression, due to methylation, promotes NSCLC cell proliferation, migration and invasion by targeting mucin 1. Therefore, miR-145 may be a valuable therapeutic target for NSCLC.

Robust meta-analysis of gene expression using the elastic net

Meta-analysis of gene expression has enabled numerous insights into biological systems, but current methods have several limitations. We developed a method to perform a meta-analysis using the elastic net, a powerful and versatile approach for classification and regression. To demonstrate the utility of our method, we conducted a meta-analysis of lung cancer gene expression based on publicly available data. Using 629 samples from five data sets, we trained a multinomial classifier to distinguish between four lung cancer subtypes. Our meta-analysis-derived classifier included 58 genes and achieved 91% accuracy on leave-one-study-out cross-validation and on three independent data sets. Our method makes meta-analysis of gene expression more systematic and expands the range of questions that a meta-analysis can be used to address. As the amount of publicly available gene expression data continues to grow, our method will be an effective tool to help distill these data into knowledge.

MUC1-C activates the TAK1 inflammatory pathway in colon cancer

The mucin 1 (MUC1) oncoprotein has been linked to the inflammatory response by promoting cytokine-mediated activation of the NF-κB pathway. The TGF-β-activated kinase 1 (TAK1) is an essential effector of proinflammatory NF-κB signaling that also regulates cancer cell survival. The present studies demonstrate that the MUC1-C transmembrane subunit induces TAK1 expression in colon cancer cells. MUC1 also induces TAK1 in a MUC1(+/-)/IL-10(-/-) mouse model of colitis and colon tumorigenesis. We show that MUC1-C promotes NF-κB-mediated activation of TAK1 transcription and, in a positive regulatory loop, MUC1-C contributes to TAK1-induced NF-κB signaling. In this way, MUC1-C binds directly to TAK1 and confers the association of TAK1 with TRAF6, which is necessary for TAK1-mediated activation of NF-κB. Targeting MUC1-C thus suppresses the TAK1NF-κB pathway, downregulates BCL-XL and in turn sensitizes colon cancer cells to MEK inhibition. Analysis of colon cancer databases further indicates that MUC1, TAK1 and TRAF6 are upregulated in tumors associated with decreased survival and that MUC1-C-induced gene expression patterns predict poor outcomes in patients. These results support a model in which MUC1-C-induced TAK1NF-κB signaling contributes to intestinal inflammation and colon cancer progression.

Glycosylation alterations in lung and brain cancer

Alterations in glycosylation are common in cancer and are thought to contribute to disease. Lung cancer and primary malignant brain cancer, most commonly glioblastoma, are genetically heterogeneous diseases with extremely poor prognoses. In this review, we summarize the data demonstrating that glycosylation is altered in lung and brain cancer. We then use specific examples to highlight the diverse roles of glycosylation in these two deadly diseases and illustrate shared mechanisms of oncogenesis. In addition to alterations in glycoconjugate biosynthesis, we also discuss mechanisms of postsynthetic glycan modification in cancer. We suggest that alterations in glycosylation in lung and brain cancer provide novel tumor biomarkers and therapeutic targets.

Targeting the oncogenic MUC1-C protein inhibits mutant EGFR-mediated signaling and survival in non-small cell lung cancer cells

PURPOSE

Non-small cell lung cancers (NSCLC) that express EGF receptor with activating mutations frequently develop resistance to EGFR kinase inhibitors. The mucin 1 (MUC1) heterodimeric protein is aberrantly overexpressed in NSCLC cells and confers a poor prognosis; however, the functional involvement of MUC1 in mutant EGFR signaling is not known.

EXPERIMENTAL DESIGN

Targeting the oncogenic MUC1 C-terminal subunit (MUC1-C) in NSCLC cells harboring mutant EGFR was studied for effects on signaling, growth, clonogenic survival, and tumorigenicity.

RESULTS

Stable silencing of MUC1-C in H1975/EGFR(L858R/T790M) cells resulted in downregulation of AKT signaling and inhibition of growth, colony formation, and tumorigenicity. Similar findings were obtained when MUC1-C was silenced in gefitinib-resistant PC9GR cells expressing EGFR(delE746_A750/T790M). The results further show that expression of a MUC1-C(CQC → AQA) mutant, which blocks MUC1-C homodimerization, suppresses EGFR(T790M), AKT and MEK → ERK activation, colony formation, and tumorigenicity. In concert with these results, treatment of H1975 and PC9GR cells with GO-203, a cell-penetrating peptide that blocks MUC1-C homodimerization, resulted in inhibition of EGFR, AKT, and MEK → ERK signaling and in loss of survival. Combination studies of GO-203 and afatinib, an irreversible inhibitor of EGFR, further demonstrate that these agents are synergistic in inhibiting growth of NSCLC cells harboring the activating EGFR(T790M) or EGFR(delE746-A750) mutants.

CONCLUSIONS

These findings indicate that targeting MUC1-C inhibits mutant EGFR signaling and survival, and thus represents a potential approach alone and in combination for the treatment of NSCLCs resistant to EGFR kinase inhibitors.