Vaccine against MUC1 antigen expressed in inflammatory bowel disease and cancer lessens colonic inflammation and prevents progression to colitis-associated colon cancer

The role of adenocarcinoma subtypes and immunohistochemistry in predicting lymph node metastasis in early invasive lung adenocarcinoma

BACKGROUND

Identifying lymph node metastasis areas during surgery for early invasive lung adenocarcinoma remains challenging. The aim of this study was to develop a nomogram mathematical model before the end of surgery for predicting lymph node metastasis in patients with early invasive lung adenocarcinoma.

METHODS

In this study, we included patients with invasive lung adenocarcinoma measuring ≤ 2 cm who underwent pulmonary resection with definite pathology at Qilu Hospital of Shandong University from January 2020 to January 2022. Preoperative biomarker results, clinical features, and computed tomography characteristics were collected. The enrolled patients were randomized into a training cohort and a validation cohort in a 7:3 ratio. The training cohort was used to construct the predictive model, while the validation cohort was used to test the model independently. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors. The prediction model and nomogram were established based on the independent risk factors. Recipient operating characteristic (ROC) curves were used to assess the discrimination ability of the model. Calibration capability was assessed using the Hosmer-Lemeshow test and calibration curves. The clinical utility of the nomogram was assessed using decision curve analysis (DCA).

RESULTS

The overall incidence of lymph node metastasis was 13.23% (61/461). Six indicators were finally determined to be independently associated with lymph node metastasis. These six indicators were: age (P < 0.001), serum amyloid (SA) (P = 0.008); carcinoma antigen 125 (CA125) (P = 0. 042); mucus composition (P = 0.003); novel aspartic proteinase of the pepsin family A (Napsin A) (P = 0.007); and cytokeratin 5/6 (CK5/6) (P = 0.042). The area under the ROC curve (AUC) was 0.843 (95% CI: 0.779-0.908) in the training cohort and 0.838 (95% CI: 0.748-0.927) in the validation cohort. the P-value of the Hosmer-Lemeshow test was 0.0613 in the training cohort and 0.8628 in the validation cohort. the bias of the training cohort corrected C-index was 0.8444 and the bias-corrected C-index for the validation cohort was 0.8375. demonstrating that the prediction model has good discriminative power and good calibration.

CONCLUSIONS

The column line graphs created showed excellent discrimination and calibration to predict lymph node status in patients with ≤ 2 cm invasive lung adenocarcinoma. In addition, the predictive model has predictive potential before the end of surgery and can inform clinical decision making.

Enhancing T Cell and Antibody Response in Mucin-1 Transgenic Mice through Co-Delivery of Tumor-Associated Mucin-1 Antigen and TLR Agonists in C3-Liposomes

Mucin-1 (MUC1) is a highly relevant antigen for cancer vaccination due to its overexpression and hypo-glycosylation in a high percentage of carcinomas. To enhance the immune response to MUC1, our group has developed C3-liposomes that encapsulate the MUC1 antigen along with immunostimulatory compounds for direct delivery to antigen-presenting cells (APCs). C3-liposomes bind complement C3, which interacts with C3-receptors on APCs, resulting in liposomal uptake and the delivery of tumor antigens to APCs in a manner that mimics pathogenic uptake. In this study, MUC1 and Toll-like receptor (TLR) agonists were encapsulated in C3-liposomes to provoke an immune response in transgenic mice tolerant to MUC1. The immune response to the C3-bound MUC1 liposomal vaccine was assessed by ELISA, ELISpot, and flow cytometry. Co-administering TLR 7/8 agonists with MUC1 encapsulated in C3-liposomes resulted in a significant antibody response compared to non-encapsulated MUC1. This antibody response was significantly higher in females than in males. The co-encapsulation of three TLR agonists with MUC1 in C3-liposomes significantly increased antibody responses and eliminated sex-based differences. Furthermore, this immunization strategy resulted in a significantly increased T cell-response compared to other treatment groups. In conclusion, the co-delivery of MUC1 and TLR agonists via C3-liposomes greatly enhances the immune response to MUC1, highlighting its potential for antigen-specific cancer immunotherapy.

Vaccines for immune tolerance against autoimmune disease

The high prevalence and rising incidence of autoimmune diseases have become a prominent public health issue. Autoimmune disorders result from the immune system erroneously attacking the body's own healthy cells and tissues, causing persistent inflammation, tissue injury, and impaired organ function. Existing treatments primarily rely on broad immunosuppression, leaving patients vulnerable to infections and necessitating lifelong treatments. To address these unmet needs, an emerging frontier of vaccine development aims to restore immune equilibrium by inducing immune tolerance to autoantigens, offering a potential avenue for a cure rather than mere symptom management. We discuss this burgeoning field of vaccine development against inflammation and autoimmune diseases, with a focus on common autoimmune disorders, including multiple sclerosis, type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease, and systemic lupus erythematosus. Vaccine-based strategies provide a new pathway for the future of autoimmune disease therapeutics, heralding a new era in the battle against inflammation and autoimmunity.

Vaccination and Microbiota Manipulation Approaches for Colon Cancer Prevention in Rodent Models

Colorectal cancer represents the third most common cancer type worldwide and is a leading cause of cancer-related mortality in the United States and Western countries. Rodent models have been invaluable to study the etiology of colorectal cancer and to test novel chemoprevention avenues. In the past, the laboratory mouse has become one of the best preclinical models for these studies due to the availability of genetic information for commonly used mouse strains with well-established and precise gene targeting and transgenic techniques. Well-established chemical mutagenesis technologies are also being used to develop mouse and rat models of colorectal cancer for prevention and treatment studies. In addition, xenotransplantation of cancer cell lines and patient-derived xenografts has been useful for preclinical prevention studies and drug development. This review focuses on the recent use of rodent models to evaluate the utility of novel strategies in the prevention of colon cancers including immune prevention approaches and the manipulation of the intestinal microbiota.

Prevention of Inflammation-Driven Colon Carcinogenesis in Human MUC1 Transgenic Mice by Vaccination with MUC1 DNA and Dendritic Cells

The preventive efficacy of MUC1-specific DNA immunization on inflammation-driven colon carcinogenesis in human MUC1 transgenic (MUC1.Tg) mice was investigated. Mice were vaccinated with MUC1 DNA mixed with autologous bone-marrow-derived dendritic cells (BMDCs), and then colonic tumors were induced by azoxymethane (AOM) injection and oral administration of dextran sulfate sodium (DSS). Two types of tumors, squamous metaplasia and tubular adenoma, were observed. Both expressed high levels of MUC1 as indicated by the binding of anti-MUC1 antibodies with different specificities, whereas MUC1 expression was not detected in normal colonic mucosa. When mice were immunized with MUC1 DNA + BMDCs, tumor incidence, tumor number, and tumor size were significantly reduced. In contrast, vaccination with MUC1 DNA alone or BMDCs alone was ineffective in reducing tumor burden. Inflammation caused by DSS was not suppressed by the MUC1 DNA + BMDCs vaccination. Furthermore, MUC1 protein expression levels, as judged by anti-MUC1 antibody binding in tumors grown after vaccination, did not significantly differ from the control. In conclusion, an inflammation-driven carcinogenesis model was established in MUC1.Tg mice, closely resembling human colon carcinogenesis. In this model, vaccination with MUC1 DNA + BMDCs was effective in overriding MUC1 tolerance and reducing the tumor burden by a mechanism not affecting the level of colonic inflammation.

Vaccination-Based Immunoprevention of Colorectal Tumors: A Primer for the Clinician

Colorectal cancer (CRC) continues to be a significant public health problem worldwide. CRC screening programs have reduced the incidence rates of CRCs but still suffer from the problems of missed lesions and interval cancers. Chemopreventive strategies against CRC would benefit high-risk populations but trials testing synthetic and naturally occurring compounds have not yielded a front runner. Immune mechanisms promoting cancer have been modulated to develop immunotherapy for cancer treatment that has revolutionized cancer management, but could also be applied to cancer interception, that is, cancer immunoprevention. Cancer immunoprevention refers to approaches that can enhance the immune system, either directly or by removing natural breaks such as immune checkpoints, to survey and destroy tumor cells. In this primer, we aim to explain the concepts behind vaccine-based cancer immunoprevention. Multiple cancer vaccines have been tried in advanced cancer populations, but most have failed primarily because of an immunosuppressive environment that accompanies advanced cancers. Preventive vaccines in immunocompetent hosts may have a better clinical response compared with therapeutic vaccines in immunosuppressed hosts. The first randomized controlled trial testing the mucin1 vaccine against CRC in the prevention setting has been successfully completed. For the benefit of the clinician, we briefly discuss important concepts related to the workings of preventive vaccines. Prevention with vaccines is a highly attractive approach because of the potential for highly targeted therapy with minimal side effects that could theoretically provide lifelong protection.

Post-Translational Modifications in Tumor-Associated Antigens as a Platform for Novel Immuno-Oncology Therapies

Post-translational modifications (PTMs) are generated by adding small chemical groups to amino acid residues after the translation of proteins. Many PTMs have been reported to correlate with tumor progression, growth, and survival by modifying the normal functions of the protein in tumor cells. PTMs can also elicit humoral and cellular immune responses, making them attractive targets for cancer immunotherapy. This review will discuss how the acetylation, citrullination, and phosphorylation of proteins expressed by tumor cells render the corresponding tumor-associated antigen more antigenic and affect the immune response in multiple cancers. In addition, the role of glycosylated protein mucins in anti-cancer immunotherapy will be considered. Mucin peptides in combination with stimulating adjuvants have, in fact, been utilized to produce anti-tumor antibodies and vaccines. Finally, we will also outline the results of the clinical trial exploiting glycosylated-MUC1 as a vaccine in different cancers. Overall, PTMs in TAAs could be considered in future therapies to result in lasting anti-tumor responses.

Multidrug Resistance in Cancer: Understanding Molecular Mechanisms, Immunoprevention and Therapeutic Approaches

Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

Mammalian Neuraminidases in Immune-Mediated Diseases: Mucins and Beyond

Mammalian neuraminidases (NEUs), also known as sialidases, are enzymes that cleave off the terminal neuraminic, or sialic, acid resides from the carbohydrate moieties of glycolipids and glycoproteins. A rapidly growing body of literature indicates that in addition to their metabolic functions, NEUs also regulate the activity of their glycoprotein targets. The simple post-translational modification of NEU protein targets-removal of the highly electronegative sialic acid-affects protein folding, alters protein interactions with their ligands, and exposes or covers proteolytic sites. Through such effects, NEUs regulate the downstream processes in which their glycoprotein targets participate. A major target of desialylation by NEUs are mucins (MUCs), and such post-translational modification contributes to regulation of disease processes. In this review, we focus on the regulatory roles of NEU-modified MUCs as coordinators of disease pathogenesis in fibrotic, inflammatory, infectious, and autoimmune diseases. Special attention is placed on the most abundant and best studied NEU1, and its recently discovered important target, mucin-1 (MUC1). The role of the NEU1 - MUC1 axis in disease pathogenesis is discussed, along with regulatory contributions from other MUCs and other pathophysiologically important NEU targets.

Vaccines for Non-Viral Cancer Prevention

Cancer vaccines are a type of immune therapy that seeks to modulate the host’s immune system to induce durable and protective immune responses against cancer-related antigens. The little clinical success of therapeutic cancer vaccines is generally attributed to the immunosuppressive tumor microenvironment at late-stage diseases. The administration of cancer-preventive vaccination at early stages, such as pre-malignant lesions or even in healthy individuals at high cancer risk could increase clinical efficacy by potentiating immune surveillance and pre-existing specific immune responses, thus eliminating de novo appearing lesions or maintaining equilibrium. Indeed, research focus has begun to shift to these approaches and some of them are yielding encouraging outcomes.

Prevention of colitis-associated colon cancer using a vaccine to target abnormal expression of the MUC1 tumor antigen

Association between chronic inflammation and cancer development is exemplified by inflammatory bowel disease (IBD) where patients with chronic uncontrolled colitis have a significantly increased risk of developing colitis-associated colorectal cancer (CACC). CACC appears to progresses through the inflammation-dysplasia-carcinoma sequence. This highlights the need to identify targets and interventions that reduce inflammation and prevent development of dysplasia in the context of IBD. Using the dextran sulfate sodium (DSS) mouse model of chronic colitis and CACC, we show that an important target of intervention in human disease would be the epithelial cell molecule MUC1 that is aberrantly expressed on inflamed colonocytes and promotes inflammation and progression to CACC. We show that a MUC1 vaccine can ameliorate chronic colitis and prevent development of dysplasia in the colon and thus extend survival in human MUC1 transgenic mice. This study supports the potential of prophylactic vaccines to target antigens that become aberrantly expressed in chronic inflammation (e.g., IBD) and continue to be expressed on the associated cancers (e.g., colon cancer), to prevent and/or treat both diseases.

Altered Expression of the Epithelial Mucin MUC1 Accompanies Endoscopic Recurrence of Postoperative Crohn's Disease

BACKGROUND

MUC1-glycoprotein is expressed at low levels and in fully glycosylated form on epithelial cells. Inflammation causes MUC1 overexpression and hypoglycosylation. We hypothesized that overexpression of hypoglycosylated MUC1 would be found in postoperative Crohn's disease (CD) recurrence and could be considered an additional biomarker of recurrence severity.

METHODS

We examined archived neo-terminal ileum biopsies from patients with prior ileocecal resection who had postoperative endoscopic assessment of CD recurrence and given a Rutgeerts ileal recurrence score. Consecutive tissue sections were stained using 2 different anti-MUC1 antibodies, HMPV that recognizes all forms of MUC1 and 4H5 that recognizes only inflammation-associated hypoglycosylated MUC1.

RESULTS

A total of 71 postoperative CD patients were evaluated. There was significant increase in MUC1 expression of both glycosylated/normal (P<0.0001) and hypoglycosylated/abnormal (P<0.0001) forms in patients with severe endoscopic CD recurrence (i3+i4), ileal score i2, compared with patients in endoscopic remission (i0+i1). Results were similar regardless of anti-TNF-α use. Although MUC1 expression and Rutgeerts scores were in agreement when characterizing the majority of cases, there were a few exceptions where MUC1 expression was characteristic of more severe recurrence than implied by Rutgeerts score.

CONCLUSIONS

MUC1 is overexpressed and hypoglycosylated in neo-terminal ileum tissue of patients with postoperative CD recurrence. Increased levels are associated with more severe endoscopic recurrence scores, and this is not influenced by anti-TNF-α use. Discrepancies found between Rutgeerts scores and MUC1 expression suggest that addition of MUC1 as a biomarker of severity of postoperative CD recurrence may improve categorization of recurrence status and consequently treatment decisions.

An Overview of Cancer Prevention: Chemoprevention and Immunoprevention

Cancer prevention encompasses a broad spectrum of strategies designed to lower the chance of developing cancer and reduce the morbidity of established cancer. There are three levels of cancer prevention. Eliminating or mitigating cancer risk factors by adopting healthy behaviors and lifestyles, such as avoiding tobacco and alcohol use, exercising, eating a healthy diet, and applying sunscreen to protect against UV exposure, belongs to primary prevention and is the easiest and most effective way of preventing cancer for the general public. Secondary prevention includes screening to identify precancerous lesions and taking intervention measures to prevent disease progression to malignancy. Tertiary prevention refers to reducing or controlling the symptoms and morbidity of established cancer or the morbidity caused by cancer therapy. For high-risk populations, chemopreventive agents, such as selective estrogen receptor modulators (including tamoxifan and raloxifene) in breast cancer prevention and non-steroidal anti-inflammatory drugs (aspirin) in colorectal cancer prevention, and immunoprevention using human papillomavirus and hepatitis B virus vaccines in infection-related cancers have shown clear clinical benefits of reducing cancer incidences. In this review, we will summarize the current status of cancer prevention, focusing on the major agents that are clinically used for chemoprevention and immunoprevention.

Mass spectrometry for the identification and analysis of highly complex glycosylation of therapeutic or pathogenic proteins

INTRODUCTION

Protein glycosylation influences characteristics such as folding, stability, protein interactions, and solubility. Therefore, glycan moieties of therapeutic proteins and proteins that are likely associated with disease pathogenesis should be analyzed in-depth, including glycan heterogeneity and modification sites. Recent advances in analytical methods and instrumentation have enabled comprehensive characterization of highly complex glycosylated proteins.

AREA COVERED

The following aspects should be considered when analyzing glycosylated proteins: sample preparation, chromatographic separation, mass spectrometry (MS) and fragmentation methods, and bioinformatics, such as software solutions for data analyses. Notably, analysis of glycoproteins with heavily sialylated glycans or multiple glycosylation sites requires special considerations. Here, we discuss recent methodological advances in MS that provide detailed characterization of heterogeneous glycoproteins.

EXPERT OPINION

As characterization of complex glycosylated proteins is still analytically challenging, the function or pathophysiological significance of these proteins is not fully understood. To reproducibly produce desired forms of therapeutic glycoproteins or to fully elucidate disease-specific patterns of protein glycosylation, a highly reproducible and robust analytical platform(s) should be established. In addition to advances in MS instrumentation, optimization of analytical and bioinformatics methods and utilization of glycoprotein/glycopeptide standards is desirable. Ultimately, we envision that an automated high-throughput MS analysis will provide additional power to clinical studies and precision medicine.

Antibodies specific for disease-associated antigens (DAA) expressed in non-malignant diseases reveal potential new tumor-associated antigens (TAA) for immunotherapy or immunoprevention

Immune responses to a large number of mutated and non-mutated tumor antigens have been studied in an attempt to unravel the highly complex immune response to cancer. Better understanding of both the effectors and the targets of successful immunosurveillance can inform various immunotherapeutic approaches, which can strengthen or replace natural immunosurveillance that a tumor has managed to escape. In this review we highlight targets of antibodies generated in the context of diseases other than cancer, such as asthma, allergies, autoimmune disorders, inflammation and infections, where the antibody presence correlates either with an increased or a reduced lifetime risk of cancer. We focus on their target antigens, self-molecules abnormally expressed on diseased cells or cross-reactive with exogenous antigens and found on cancer cells as tumor associated antigens (TAA). We refer to them as disease-associated antigens (DAA). We review 4 distinct categories of antibodies according to their target DAA, their origin and their reported impact on cancer risk: natural antibodies, autoantibodies, long-term memory antibodies and allergy-associated antibodies. Increased understanding and focus on their specific targets could enable a more rational choice of antigens for both therapeutic and preventative cancer vaccines and other more effective and less toxic cancer immunotherapies.

AACR White Paper: Shaping the Future of Cancer Prevention - A Roadmap for Advancing Science and Public Health

The recent pace, extent, and impact of paradigm-changing cancer prevention science has been remarkable. The American Association for Cancer Research (AACR) convened a 3-day summit, aligned with five research priorities: (i) Precancer Atlas (PCA). (ii) Cancer interception. (iii) Obesity-cancer linkage, a global epidemic of chronic low-grade inflammation. (iv) Implementation science. (v) Cancer disparities. Aligned with these priorities, AACR co-led the Lancet Commission to formally endorse and accelerate the NCI Cancer Moonshot program, facilitating new global collaborative efforts in cancer control. The expanding scope of creative impact is perhaps most startling-from NCI-funded built environments to AACR Team Science Awarded studies of Asian cancer genomes informing global primary prevention policies; cell-free epigenetic marks identifying incipient neoplastic site; practice-changing genomic subclasses in myeloproliferative neoplasia (including germline variant tightly linked to JAK2 V617F haplotype); universal germline genetic testing for pancreatic cancer; and repurposing drugs targeting immune- and stem-cell signals (e.g., IL-1β, PD-1, RANK-L) to cancer interception. Microbiota-driven IL-17 can induce stemness and transformation in pancreatic precursors (identifying another repurposing opportunity). Notable progress also includes hosting an obesity special conference (connecting epidemiologic and molecular perspectives to inform cancer research and prevention strategies), co-leading concerted national implementation efforts in HPV vaccination, and charting the future elimination of cancer disparities by integrating new science tools, discoveries and perspectives into community-engaged research, including targeted counter attacks on e-cigarette ad exploitation of children, Hispanics and Blacks. Following this summit, two unprecedented funding initiatives were catalyzed to drive cancer prevention research: the NCI Cancer Moonshot (e.g., PCA and disparities); and the AACR-Stand Up To Cancer bold "Cancer Interception" initiative.

Circulating Myeloid Derived Suppressor Cells (MDSC) That Accumulate in Premalignancy Share Phenotypic and Functional Characteristics With MDSC in Cancer

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells that accumulate in circulation of cancer patients and at tumor sites where they suppress anti-tumor immunity. We previously reported that in a colon cancer prevention trial of a MUC1 vaccine tested in individuals at increased risk for colon cancer, those who did not mount immune response to the vaccine had higher pre-vaccination levels of circulating MDSC compared to those who did. We also reported that individuals with pancreatic premalignancy, Intraductal Papillary Mucinous Neoplasm (IPMN), had increased circulating levels of MDSC that inversely correlated with spontaneous antibody responses against the pancreatic tumor associated antigen MUC1, abnormally expressed on IPMN. Accumulation of MDSC in cancer and their immunosuppressive role had been well established but their presence in premalignancy was unexpected. In this study we compared MDSC in premalignancy with those in cancer with the hypothesis that there might be differences in the composition of various MDSC subpopulations and their immunosuppressive functions due to different lengths of exposure to disease and/or different tissue microenvironments. In cohorts of patients with premalignant polyps, colon cancer, premalignant IPMN, and pancreatic cancer, we confirmed higher levels of MDSC in premalignancy compared to healthy controls, higher levels of MDSC in cancer compared to premalignancy, but no difference in their subpopulation composition or immunosuppressive capacity. We show that levels of MDSC in premalignancy correlate negatively in vivo with spontaneous MUC1-specific antibody responses and in vitro with polyclonal T cell proliferation and IFN-γ secretion.

Mucin-1 expression and localization in epithelial cells shows characteristic and distinct patterns in inflammatory bowel diseases and colorectal cancer

Alterations in colonic mucus secretion are linked to the induction and maintenance of inflammation during inflammatory bowel disease (IBD) and its progression to colorectal cancer (CRC). MUC1, a multifunctional glycoprotein, is the best studied cell surface mucin in mouse models of IBD and CRC. However, little information on MUC1 expression and localization in different types of pathologic human colon mucosa is available. In this work, expression and subcellular localization of MUC1 in different types of diseased human colon mucosa from a cohort of Tunisian patients is analyzed and correlated with the type of disorder. Colon tissue samples were obtained from 39 cases of CRC and 18 cases of IBD. 13 cases of normal adjacent colon mucosa tissues served as controls. Biopsies were subjected to immunohistochemical analysis of MUC1 expression. Signals were quantified densitometrically and characterized with regard to tissue and intracellular distribution. Results were then correlated with the different types of colon disorder. Immunohistochemical investigation of MUC1 in a cohort of inflammatory bowel diseases and colorectal cancer showed a significant divergence in the expression of MUC1 in terms intensity (18.96% ± 0.55 vs 27.26% ± 1.24 respectively; P=0.005) and localization between the two types of lesions (30.76% vs 70.96% respectively; P=0.0199). Our findings show divergent characteristic patterns for MUC1 expression and localization in different types of pathologic alterations of the colon mucosa. These results are of potential diagnostic and predictive clinical value.

Statins dose-dependently exert a significant chemopreventive effect on colon cancer in patients with chronic obstructive pulmonary disease: A population-based cohort study

Purpose

We evaluated the chemopreventive effect of statins on colon cancer in patients with chronic obstructive pulmonary disease (COPD) and identified the statin exerting the strongest chemopreventive effect.

Methods

Using the National Health Insurance Research Database, we identified patients who received a COPD diagnosis in Taiwan between January 1, 2001, and December 31, 2012, and included them in the study cohort. Each patient was followed to assess the colon cancer risk and protective factors. A propensity score was derived using a logistic regression model to estimate the effect of statins by accounting for covariates predicted during the intervention (statins). To examine the dose–response relationship, we categorized statin doses into four groups in each cohort [<28, 28–90, 91–365, and >365 cumulative defined daily dose].

Results

Compared with the statin nonusers, the adjusted hazard ratio (aHR) for colon cancer decreased in the statin users (aHR = 0.52, 95% confidence interval = 0.44, 0.62). Hydrophilic statins exerted a stronger preventive effect against colon cancer. Regarding the statin type, lovastatin, pravastatin, and fluvastatin nonsignificantly reduced the colon cancer risk in the patients with COPD. Compared with the statin nonusers, the aHRs for colon cancer decreased in the individual statin users (rosuvastatin, simvastatin, and atorvastatin: aHRs = 0.28, 0.64, and 0.65, respectively). In the sensitivity analysis, statins dose-dependently reduced the colon cancer risk.

Conclusions

Statins dose-dependently exert significant chemopreventive effects on colon cancer in patients with COPD, with rosuvastatin exerting the largest chemopreventive effect.

Colorectal cancer prevention: Immune modulation taking the stage

Prevention or early detection is one of the most promising strategies against colorectal cancer (CRC), the second leading cause of cancer death in the US. Recent studies indicate that antitumor immunity plays a key role in CRC prevention. Accumulating evidence suggests that immunosurveillance represents a critical barrier that emerging tumor cells have to overcome in order to sustain the course of tumor development. Virtually all of the agents with cancer preventive activity have been shown to have an immune modulating effect. A number of immunoprevention studies aimed at triggering antitumor immune response against early lesions have been performed, some of which have shown promising results. Furthermore, the recent success of immune checkpoint blockade therapy reinforces the notion that cancers including CRC can be effectively intervened via immune modulation including immune normalization, and has stimulated various immune-based combination prevention studies. This review summarizes recent advances to help better harness the immune system in CRC prevention.

Cancer Prevention: Lessons Learned and Future Directions

In this review, we address selected areas that are central to the state-of-the-art of cancer prevention science. The emphasis on prevention as a viable and critical approach to decreasing cancer mortality has gained traction in recent years, evidenced by its inclusion in the US Vice President's Cancer Initiative (also termed 'Moonshot'). Cancer prevention occurs by arresting, slowing down, or reversing the carcinogenic process before invasion into surrounding tissue or by avoiding or blocking causative exposure. An important challenge is to identify individuals who will benefit most from preventive interventions with the least possible harm. Preventive interventions range from avoiding known carcinogens (e.g., tobacco or asbestos) to intervening with anticarcinogenic strategies (behavioral modifications , such as diet and exercise; medications; nutritional agents; and vaccination against causative agents). Here, we focus on active intervention with measures involving pharmaceutical and immunological agents.

Inflammatory cells implicated in neoplasia development in idiopathic inflammatory bowel disease

The inflammatory mechanisms that lead to the clinical symptoms that are grouped under the term inflammatory bowel disease have not been fully characterized. Although a specific mechanism has not been identified, inflammatory bowel disease is believed to be related to an inability by the immune system to shut active inflammation within the intestine. Many contributing factors have been implicated in the disease process. Based on population studies, patients with inflammatory bowel disease have an increased risk for neoplastic development. Although no specific immune cell has been implicated in neoplastic development within this patient population, several immune cells have been implicated as possible etiologies in inflammatory bowel disease. In this review, we will review the clinical evidence about the risk for neoplastic development in inflammatory bowel disease and the current clinical guidelines to survey this patient population. We will also review the pathologic assessment of inflammation within this patient population as well the underlying immune cells and cytokines that have been implicated in the etiology of inflammatory bowel disease.

Abnormally glycosylated MUC1 establishes a positive feedback circuit of inflammatory cytokines, mediated by NF-κB p65 and EzH2, in colitis-associated cancer

The abnormal hypoglycosylated form of the epithelial mucin MUC1 is over-expressed in chronic inflammation and on human adenocarcinomas, suggesting its potential role in inflammation-driven tumorigenesis. The presence of human MUC1 aggravates colonic inflammation and increases tumor initiation and progression in an in vivo AOM/DSS mouse model of colitis-associated cancer (CAC). High expression levels of pro-inflammatory cytokines, including TNF-α and IL-6, were found in MUC1+ inflamed colon tissues. Exogenous TNF-α promoted the transcriptional activity of MUC1 as well as over-expression of its hypoglycosylated form in intestinal epithelial cells (IECs). In turn, hypoglycosylated MUC1 in IECs associated with p65 and up-regulated the expression of NF-κB-target genes encoding pro-inflammatory cytokines. Intestinal chronic inflammation also increased the expression of histone methyltransferase Enhancer of Zeste protein-2 (EzH2) and its interaction with cytokine promoters. Consequently, EzH2 was a positive regulator of MUC1 and p65-mediated IL-6 and TNF-α gene expression, and this function was not dependent on its canonical histone H3K27 methyltransferase activity. Our findings provide a mechanistic basis for already known tumorigenic role of the hypoglycosylated MUC1 in CAC, involving a transcriptional positive feedback loop of pro-inflammatory cytokines.

Current modalities in cancer immunotherapy: Immunomodulatory antibodies, CARs and vaccines

Successes of immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cell therapy in curing patients with otherwise lethal cancers have validated immunotherapy as a treatment for cancer and have inspired excitement for its broader potential. Most promising is the ability of each approach to eliminate bulky and advanced-stage cancers and to achieve durable cures. Despite this success, to date only a subset of cancer patients and a limited number of cancer types respond to these therapies. A major goal now is to expand the types of cancer and number of patients who can be successfully treated. To this end a multitude of immunotherapies are being tested clinically in new combinations, and many new immunomodulatory antibodies and CARs are in development. A third major immunotherapeutic approach with renewed interest is cancer vaccines. While over 20years of therapeutic cancer vaccine trials have met with limited success, these studies have laid the groundwork for the use of therapeutic vaccines in combination with other immunotherapies or alone as prophylactic cancer vaccines. Prophylactic vaccines are now poised to revolutionize cancer prevention as they have done for the prevention of infectious diseases. In this review we examine three major cancer immunotherapy modalities: immunomodulatory antibodies, CAR T cell therapy and vaccines. For each we describe the current state of the art and outline major challenges and research directions forward.

Clinicopathological and immunohistochemical features of lung invasive mucinous adenocarcinoma based on computed tomography findings

Background

We performed an analysis to clarify differences in clinicopathological and molecular features of lung invasive mucinous adenocarcinoma (IMA) based on computed tomography (CT) findings and their impact on prognosis.

Patients and methods

On the basis of CT findings, we divided lung IMA into three subtypes: solid, bubbling, and pneumonic. We then investigated differences in clinicopathological characteristics, prognosis, and the expressions of well-identified biomarkers, including cyclooxygenase-2 (Cox-2), excision repair cross-complementation group 1 (ERCC1), ribonucleotide reductase M1 (RRM1), class III beta-tubulin, thymidylate synthase (TS), secreted protein acidic and rich in cysteine (SPARC), programmed cell death-1 ligand-1 (PD-L1), and epidermal growth factor receptor mutation, among the three subtypes.

Results

A total of 29 patients with resected lung IMA were analyzed. Compared with the solid or bubbling type, the pneumonic type had a higher proportion of symptoms, a larger tumor size, a higher pathological stage, and a significantly worse prognosis. The immunohistochemical findings tended to show high expression of RRM1, class III beta-tubulin, and Cox-2 in the tumor and of SPARC in the stroma, but not of ERCC1, TS, and PD-L1 in the tumor. None of the biomarkers with high expression levels in the tumor were prognostic biomarkers, but the expression of SPARC in the stroma was correlated with a poor outcome.

Conclusion

Clinical and pathological features, in conjunction with molecular data, indicate that IMA should be divided into different subgroups. In our results, the pneumonic type was correlated with a significantly worse outcome. Further studies should be performed to confirm our conclusion and to explore its molecular implications.

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.

Antibodies elicited by the first non-viral prophylactic cancer vaccine show tumor-specificity and immunotherapeutic potential

MUC1 is a shared tumor antigen expressed on >80% of human cancers. We completed the first prophylactic cancer vaccine clinical trial based on a non-viral antigen, MUC1, in healthy individuals at-risk for colon cancer. This trial provided a unique source of potentially effective and safe immunotherapeutic drugs, fully-human antibodies affinity-matured in a healthy host to a tumor antigen. We purified, cloned, and characterized 13 IgGs specific for several tumor-associated MUC1 epitopes with a wide range of binding affinities. These antibodies bind hypoglycosylated MUC1 on human cancer cell lines and tumor tissues but show no reactivity against fully-glycosylated MUC1 on normal cells and tissues. We found that several antibodies activate complement-mediated cytotoxicity and that T cells carrying chimeric antigen receptors with the antibody variable regions kill MUC1(+) target cells, express activation markers, and produce interferon gamma. Fully-human and tumor-specific, these antibodies are candidates for further testing and development as immunotherapeutic drugs.

Cancer immunoprevention

Cancer immunotherapy is now a reality. The results are phenomenal but the cost is outrageous. Even if the cost eventually comes down and immunotherapy becomes more broadly available, using the knowledge derived from immunotherapy to apply to immunoprevention would be a good strategy. The most likely approach to cancer immunoprevention is cancer vaccines. To date, cancer vaccines have been tested mostly in the setting of advanced disease. Numerous immunosuppressive mechanisms have been identified in the tumor microenvironment as well as systemically that compromise the ability of cancer patients to respond to the vaccines. Multiple approaches are being tested to improve therapeutic cancer vaccine efficacy, including combinations with other immunotherapies. An alternative approach is to administer the vaccines to individuals without cancer but at high risk for cancer. Data in support of this approach and immunoprevention in general is accumulating and clinical testing has started.

MUC1 upregulation promotes immune resistance in tumor cells undergoing brachyury-mediated epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a molecular and cellular program in which epithelial cells lose their well-differentiated phenotype and adopt mesenchymal characteristics. This process, which occurs naturally during embryogenesis, has also been shown to be associated with cancer progression and with tumor recurrence following conventional therapies. Brachyury is a transcription factor that mediates EMT during development, and is aberrantly expressed in various human cancers where it promotes tumor cell EMT, metastatic dissemination, and resistance to conventional therapies. We have recently shown that very high expression of brachyury can protect tumor cells against immune cell-mediated cytotoxicity. In seeking to elucidate mechanisms of immunotherapy resistance, we have discovered a novel positive association between brachyury and mucin-1 (MUC1). MUC1 is overexpressed in the majority of carcinomas, and it has been shown to mediate oncogenic signaling and confer resistance to genotoxic agents. We found that MUC1 is concomitantly upregulated in tumor cell lines that highly express brachyury due to an enhancement of MUC1 mRNA stability. Analysis of patient lung tumor tissues also identified a positive association between these two proteins in the majority of samples. Inhibition of MUC1 by siRNA-based gene silencing markedly enhanced the susceptibility of brachyury-expressing cancer cells to killing by tumor necrosis-related apoptosis-inducing ligand (TRAIL) and to perforin/granzyme-dependent lysis by immune cytotoxic cells. These studies confirm a protective role for MUC1 in brachyury-expressing cancer cells, and suggest that inhibition of MUC1 can restore the susceptibility of mesenchymal-like cancer cells to immune attack.

MUC1 (CD227): a multi-tasked molecule

Mucin 1 (MUC1 [CD227]) is a high-molecular weight (>400 kDa), type I membrane-tethered glycoprotein that is expressed on epithelial cells and extends far above the glycocalyx. MUC1 is overexpressed and aberrantly glycosylated in adenocarcinomas and in hematological malignancies. As a result, MUC1 has been a target for tumor immunotherapeutic studies in mice and in humans. MUC1 has been shown to have anti-adhesive and immunosuppressive properties, protects against infections, and is involved in the oncogenic process as well as in cell signaling. In addition, MUC1 plays a key role in the reproductive tract, in the immune system (affecting dendritic cells, monocytes, T cells, and B cells), and in chronic inflammatory diseases. Evidence for all of these roles for MUC1 is discussed herein and demonstrates that MUC1 is truly a multitasked molecule.

Immunologic approaches to cancer prevention-current status, challenges, and future perspectives

The potential of the immune system to recognize and reject tumors has been investigated for more than a century. However, only recently impressive breakthroughs in cancer immunotherapy have been seen with the use of checkpoint inhibitors. The experience with various immune-based strategies in the treatment of late cancer highlighted the importance of negative impact advanced disease has on immunity. Consequently, use of immune modulation for cancer prevention rather than therapy has gained considerable attention, with many promising results seen already in preclinical and early clinical studies. Although not without challenges, these results provide much excitement and optimism that successful cancer immunoprevention could be within our reach. In this review we will discuss the current state of predominantly primary and secondary cancer immunoprevention, relevant research, potential barriers, and future directions.

Molecular Targeted Intervention for Pancreatic Cancer

Pancreatic cancer (PC) remains one of the worst cancers, with almost uniform lethality. PC risk is associated with westernized diet, tobacco, alcohol, obesity, chronic pancreatitis, and family history of pancreatic cancer. New targeted agents and the use of various therapeutic combinations have yet to provide adequate treatments for patients with advanced cancer. To design better preventive and/or treatment strategies against PC, knowledge of PC pathogenesis at the molecular level is vital. With the advent of genetically modified animals, significant advances have been made in understanding the molecular biology and pathogenesis of PC. Currently, several clinical trials and preclinical evaluations are underway to investigate novel agents that target signaling defects in PC. An important consideration in evaluating novel drugs is determining whether an agent can reach the target in concentrations effective to treat the disease. Recently, we have reported evidence for chemoprevention of PC. Here, we provide a comprehensive review of current updates on molecularly targeted interventions, as well as dietary, phytochemical, immunoregulatory, and microenvironment-based approaches for the development of novel therapeutic and preventive regimens. Special attention is given to prevention and treatment in preclinical genetically engineered mouse studies and human clinical studies.

Challenges in the research and development of new human vaccines

The field of vaccinology was born from the observations by the fathers of vaccination, Edward Jenner and Louis Pasteur, that a permanent, positive change in the way our bodies respond to life-threatening infectious diseases can be obtained by specific challenge with the inactivated infectious agent performed in a controlled manner, avoiding the development of clinical disease upon exposure to the virulent pathogen. Many of the vaccines still in use today were developed on an empirical basis, essentially following the paradigm established by Pasteur, "isolate, inactivate, and inject" the disease-causing microorganism, and are capable of eliciting uniform, long-term immune memory responses that constitute the key to their proven efficacy. However, vaccines for pathogens considered as priority targets of public health concern are still lacking. The literature tends to focus more often on vaccine research problems associated with specific pathogens, but it is increasingly clear that there are common bottlenecks in vaccine research, which need to be solved in order to advance the development of the field as a whole. As part of a group of articles, the objective of the present report is to pinpoint these bottlenecks, exploring the literature for common problems and solutions in vaccine research applied to different situations. Our goal is to stimulate brainstorming among specialists of different fields related to vaccine research and development. Here, we briefly summarize the topics we intend to deal with in this discussion.

The antigenic repertoire of premalignant and high-risk lesions

Prophylactic vaccines have been a major advance in preventing the development of infections after exposure to pathogens. When contemplating an effective approach to cancer prevention, vaccines offer unique advantages over other more standard approaches: First, once appropriately stimulated, antigen-specific T cells will travel to all sites of disease and eradicate cells bearing the proteins to which the T cells have been primed by vaccination. Second, successful immunization will further result in the development of immunologic memory, providing lifelong immunologic surveillance. There is evidence of an adaptive tumor immune infiltrate even at the earliest stages of breast and colon cancer development. Furthermore, there is measurable immunity to lesion-associated antigens present in patients who will eventually develop malignancy even before cancer is clinically evident. Recent studies are beginning to unmask the preinvasive antigenic repertoire for these two malignancies. Preliminary experiments in transgenic mouse models of mammary and intestinal tumors suggest that immunization against antigens expressed in preinvasive and high-risk lesions may be effective in preventing the development of invasive malignancy.

Comparison of clinical features, molecular alterations, and prognosis in morphological subgroups of lung invasive mucinous adenocarcinoma

PURPOSE

We performed this analysis to distinguish the differences in two subtypes of lung invasive mucinous adenocarcinoma (IMA) with different kinds of morphological performances, in clinicopathological and molecular features, as well as prognosis.

METHODS

On the basis of morphological performance, we divided lung IMAs into two subgroups, mucus-in-cell adenocarcinoma (MICA) and mucus-out-of-cell adenocarcinoma (MOCA). We investigated differences in clinicopathological characteristics, recurrence-free survival (RFS), overall survival (OS), and a spectrum of well-identified driver-gene mutations, including EGFR, KRAS, HER2, BRAF, ALK, ROS1, and RET, between the two subgroups.

RESULTS

Of 1,699 lung adenocarcinomas, 148 were identified as IMAs (97 MICAs and 51 MOCAs). The MICA patient group had significantly better RFS than did the MOCA group (39.4 months versus 33.0 months, respectively, log rank P=0.020) and significantly better OS (54.2 months versus 45.1 months, log rank P=0.034). There were no differences in RFS and OS between those with IMAs and those with mucus-negative adenocarcinomas. The frequency of the EGFR gene mutation was significantly higher in MOCAs than in MICAs (P<0.001). In contrast, the KRAS gene had a significantly higher mutational frequency in MICAs (P=0.01). MOCAs also had a significantly higher incidence of lymph-node metastasis (P<0.05).

CONCLUSION

To our knowledge, this study represents the first comparison of clinical features, molecular alterations, and prognosis in morphological subgroups of lung IMAs. Clinical and pathological features in conjunction with molecular data indicate that IMA should be divided into different subgroups.

Mechanisms of antitumor and immune-enhancing activities of MUC1/sec, a secreted form of mucin-1

Mucin 1 (MUC1) is a polymorphic type 1 transmembrane protein found on the apical surface of normal cells lining the lumen of ducts and glands. Mucins are thought to provide mucosal protection from environmental exposures and carcinogens. An altered form of the MUC1 glycoprotein, which is hypoglycosylated, is expressed in several types of human cancers. In our laboratory, we have found that transfection of a murine mammary tumor cell line with a human secreted isoform of MUC1 rendered these DA-3 cells (DA-3/sec) incapable of growing in intact BALB/c mice. In contrast, implantation of DA-3 cells transfected with the human transmembrane isoform of MUC1 (DA-3/TM), resulted in tumor formation and ultimately death of the animals, similar to the DA-3 parental line. Importantly, inoculation of the DA-3/sec cells in immunodeficient nude mice resulted in tumor formation, indicating that the MUC1/sec molecule's antitumor activity is immunologically controlled. In this review, we summarize the studies we have performed to elucidate possible mechanisms for the immune-mediated antitumor effect of MUC1/sec and/or a unique peptide present in this mucin. Understanding these mechanisms may provide new immunotherapeutic approaches that could be used to target different types of cancer.

Identification and characterization of agonist epitopes of the MUC1-C oncoprotein

The MUC1 tumor-associated antigen is overexpressed in the majority of human carcinomas and several hematologic malignancies. Much attention has been paid to the hypoglycosylated variable number of tandem repeats (VNTR) region of the N-terminus of MUC1 as a vaccine target, and recombinant viral vector vaccines are also being evaluated that express the entire MUC1 transgene. While previous studies have described MUC1 as a tumor-associated tissue differentiation antigen, studies have now determined that the C-terminus of MUC1 (MUC1-C) is an oncoprotein, and its expression is an indication of poor prognosis in numerous tumor types. We report here the identification of nine potential CD8⁺ cytotoxic T lymphocyte epitopes of MUC1, seven in the C-terminus and two in the VNTR region, and have identified enhancer agonist peptides for each of these epitopes. These epitopes span HLA-A2, HLA-A3, and HLA-A24 major histocompatibility complex (MHC) class I alleles, which encompass the majority of the population. The agonist peptides, compared to the native peptides, more efficiently (a) generate T-cell lines from the peripheral blood mononuclear cells of cancer patients, (b) enhance the production of IFN-γ by peptide-activated human T cells, and (c) lyse human tumor cell targets in an MHC-restricted manner. The agonist epitopes described here can be incorporated into various vaccine platforms and for the ex vivo generation of human T cells. These studies provide the rationale for the T-cell-mediated targeting of the oncogenic MUC1-C, which has been shown to be an important factor in both drug resistance and poor prognosis for numerous tumor types.

Preventing cancer by targeting abnormally expressed self-antigens: MUC1 vaccines for prevention of epithelial adenocarcinomas

Prophylactic vaccines based on tumor-associated antigens (TAAs) have elicited concerns due to their potential toxicity. Because TAAs are considered self-antigens, the prediction is that such vaccines will induce autoimmunity. While this has been observed in melanoma, where an antitumor immune response leads to vitiligo, autoimmunity has almost never been seen following vaccination with numerous other TAAs. We hypothesized that antigen choice determines outcome and have been working to identify TAAs whose expression differs between normal and tumor tissue, and thus could elicit antitumor immunity without autoimmunity. Studies on the epithelial TAA MUC1 have revealed that, compared to MUC1 on normal cells, tumors, premalignant lesions, and noncancerous pathologies affecting epithelial cells express abnormal MUC1, which is not a self-antigen but rather an abnormal disease-associated antigen (DAA). This distinction, which can be made for many known TAAs, has broad implications for the design and acceptance of preventative cancer vaccines.

Downregulation of hematopoietic MUC1 during experimental colitis increases tumor-promoting myeloid-derived suppressor cells

PURPOSE

MUC1 is a tumor-associated antigen that is aberrantly expressed in cancer and inflammatory bowel disease (IBD). Even though immune cells express low MUC1 levels, their modulations of MUC1 are important in tumor progression. Consistent with previous clinical data that show increased myeloid-derived suppressor cells (MDSCs) in IBD, we now show that downregulation of MUC1 on hematopoietic cells increases MDSCs in IBD, similar to our data in tumor-bearing mice. We hypothesize that MDSC expansion in IBD is critical for tumor progression.

EXPERIMENTAL DESIGN

To mechanistically confirm the linkage between Muc1 downregulation and MDSC expansion, we generated chimeric mice that did not express Muc1 in the hematopoietic compartment (KO→WT). These mice were used in two models of colitis and colitis-associated cancer (CAC) and their responses were compared with wild-type (WT) chimeras (WT→WT).

RESULTS

KO→WT mice show increased levels of MDSCs during colitis and increased protumorigenic signaling in the colon during CAC, resulting in larger colon tumors. RNA and protein analysis show increased upregulation of metalloproteinases, collagenases, defensins, complements, growth factors, cytokines, and chemokines in KO→WT mice as compared with WT→WT mice. Antibody-mediated depletion of MDSCs in mice during colitis reduced colon tumor formation during CAC.

CONCLUSION

Development of CAC is a serious complication of colitis and our data highlight MDSCs as a targetable link between inflammation and cancer. In addition, the lack of MUC1 expression on MDSCs can be a novel marker for MDSCs, given that MDSCs are still not well characterized in human cancers.

Identification of putative immunologic targets for colon cancer prevention based on conserved gene upregulation from preinvasive to malignant lesions

The length of time required for preinvasive adenoma to progress to carcinoma, the immunogenicity of colorectal cancer (CRC), and the identification of high-risk populations make development and testing of a prophylactic vaccine for the prevention of CRC possible. We hypothesized that genes upregulated in adenoma relative to normal tissue, which maintained increased expression in CRC, would encode proteins suitable as putative targets for immunoprevention. We evaluated existing adenoma and CRC microarray datasets and identified 160 genes that were ≥2-fold upregulated in both adenoma and CRC relative to normal colon tissue. We further identified 23 genes that showed protein overexpression in colon adenoma and CRC based on literature review. Silencing the most highly upregulated genes, CDH3, CLDN1, KRT23, and MMP7, in adenoma and CRC cell lines resulted in a significant decrease in viability (P < 0.0001) and proliferation (P < 0.0001) as compared to controls and an increase in cellular apoptosis (P < 0.05 for CDH3, KRT23). Results were duplicated across cell lines representing microsatellite instability, CpG island methylator, and chromosomal instability phenotypes, suggesting immunologic elimination of cells expressing these proteins could impact the progression of all CRC phenotypes. To determine whether these proteins were immunogens, we interrogated sera from early stage CRC patients and controls and found significantly elevated CDH3 (P = 0.006), KRT23 (P = 0.0007), and MMP7 (P < 0.0001) serum immunoglobulin G in cases as compared to controls. These data show a high throughput approach to the identification of biologically relevant putative immunologic targets for CRC and identified three candidates suitable for vaccine development.

Colorectal cancer immunotherapy

Antitumor immunotherapy for colorectal cancer has been studied at the bench and bedside for decades. Some clinical trials of cancer immunotherapy have demonstrated a potential benefit for patients with colorectal cancer, yet immunotherapy remains only an experimental option for this disease. Here, we review the major immunotherapeutic approaches currently under investigation for colorectal cancer, including cancer vaccines and adoptive cell therapy. Weakness and advantages of each strategy and progress in clinical trials will be described. Examination of previous and ongoing research in colorectal cancer therapy should define a path towards identification, approval, and mainstream adoption of colorectal cancer immunotherapeutics.

MUC1 vaccine for individuals with advanced adenoma of the colon: a cancer immunoprevention feasibility study

Cancer vaccines based on human tumor-associated antigens (TAA) have been tested in patients with advanced or recurrent cancer, in combination with or following standard therapy. Their immunogenicity and therapeutic efficacy has been difficult to properly evaluate in that setting characterized by multiple highly suppressive effects of the tumor and the standard therapy on the patient's immune system. In animal models of human cancer, vaccines administered in the prophylactic setting are most immunogenic and effectively prevent cancer development and progression. We report results of a clinical study that show that in patients without cancer but with a history of premalignant lesions (advanced colonic adenomas, precursors to colon cancer), a vaccine based on the TAA MUC1 was highly immunogenic in 17 of 39 (43.6%) of vaccinated individuals, eliciting high levels of anti-MUC1 immunoglobulin G (IgG) and long-lasting immune memory. Lack of response in 22 of 39 individuals was correlated with high levels of circulating myeloid-derived suppressor cells (MDSC) prevaccination. Vaccine-elicited MUC1-specific immune response and immune memory were not associated with significant toxicity. Our study shows that vaccines based on human TAAs are immunogenic and safe and capable of eliciting long-term memory that is important for cancer prevention. We also show that in the premalignant setting, immunosuppressive environment (e.g., high levels of MDSC) might already exist in some individuals, suggesting an even earlier premalignant stage or preselection of nonimmunosuppressed patients for prophylactic vaccination.

Future directions in cancer prevention

Prevention of cancer remains the most promising strategy for reducing both its incidence and the mortality due to this disease. For more than four decades, findings from epidemiology, basic research and clinical trials have informed the development of lifestyle and medical approaches to cancer prevention. These include selective oestrogen receptor modulators and aromatase inhibitors for breast cancer, the 5-α-reductase inhibitors finasteride and dutasteride for prostate cancer, and the development of vaccines for viruses that are associated with specific cancers. Future directions include genetic, proteomic and other molecular approaches for identifying pathways that are associated with cancer initiation and development, as well as refining the search for immunologically modifiable causes of cancer.

Emerging avenues linking inflammation and cancer

The role of inflammation in carcinogenesis has been extensively investigated and well documented. Many biochemical processes that are altered during chronic inflammation have been implicated in tumorigenesis. These include shifting cellular redox balance toward oxidative stress; induction of genomic instability; increased DNA damage; stimulation of cell proliferation, metastasis, and angiogenesis; deregulation of cellular epigenetic control of gene expression; and inappropriate epithelial-to-mesenchymal transition. A wide array of proinflammatory cytokines, prostaglandins, nitric oxide, and matricellular proteins are closely involved in premalignant and malignant conversion of cells in a background of chronic inflammation. Inappropriate transcription of genes encoding inflammatory mediators, survival factors, and angiogenic and metastatic proteins is the key molecular event in linking inflammation and cancer. Aberrant cell signaling pathways comprising various kinases and their downstream transcription factors have been identified as the major contributors in abnormal gene expression associated with inflammation-driven carcinogenesis. The posttranscriptional regulation of gene expression by microRNAs also provides the molecular basis for linking inflammation to cancer. This review highlights the multifaceted role of inflammation in carcinogenesis in the context of altered cellular redox signaling.

Mucins in inflammatory bowel diseases and colorectal cancer

The gastrointestinal tract is protected by a mucus barrier with both secreted and cell-surface mucins contributing to the exclusion of luminal microbes and toxins. Alterations in the structure and/or quantity of mucins alter the barrier function of mucus and could play roles in initiating and maintaining mucosal inflammation in inflammatory bowel diseases (IBD), and in driving cancer development in the intestine. The aim of this review is to focus on the roles of the mucins in IBD. The polymorphisms of mucin genes that have been associated with susceptibility to IBD, and alterations in mucin expression as well as factors that regulate production of the mucins in IBD, are summarized. Data from animal models of intestinal inflammation, which support the importance of mucins in IBD and cancer development, are also discussed.

MUC1 protein expression in tumor cells regulates transcription of proinflammatory cytokines by forming a complex with nuclear factor-κB p65 and binding to cytokine promoters: importance of extracellular domain

MUC1 is a transmembrane glycoprotein abnormally expressed in all stages of development of human adenocarcinomas. Overexpression and hypoglycosylation of MUC1 in cancer cells compared with normal epithelial cells are likely to alter its function and affect the behavior of cancer cells. The extracellular domain, specifically the highly O-glycosylated VNTR (variable number of tandem repeats) region, plays an important role in cell-cell communication; however, we show here that it also participates intracellularly in activation of the NF-κB pathway. Transfection of MUC1(-) tumor cells with cDNA encoding MUC1 with 22 tandem repeats (MUC1/22TR) or two tandem repeats (MUC1/2TR) or two isoforms that lack the VNTR region (MUC1/Z and MUC1/Y) showed that the highest expression levels of NF-κB family members correlated with the presence of VNTR and the highest number of tandem repeats. Because expression of MUC1 with VNTR on tumors was previously associated with chemotactic activity for cells of the innate immune system, we investigated the influence of MUC1 expression on the NF-κB-dependent transcriptional regulation of proinflammatory cytokines. ChIP and real-time PCR experiments revealed that MUC1/22TR up-regulated IL-6 and TNF-α expression by binding to their promoter regions in a NF-κB p65-dependent manner in both MUC1-transfected and human breast cancer cells that express endogenous MUC1. This newly detected complex of MUC1 and p65 is a novel mechanism that tumors can use to promote inflammation and cancer development.

Cancer vaccines: moving toward prevention?

After several decades of research, recent successful phase III controlled clinical trials have renewed enthusiasm for vaccine treatment of cancer. This perspective on the report by Berta and colleagues in this issue of the journal (beginning on page 994) discusses the potential prevention of oral cancer through vaccine strategies and, in the broader context, ideal characteristics of tumor antigens as candidates for vaccines for both treating and preventing cancer, potential primary and secondary prevention settings for vaccines, desirable types of immune effectors induced by vaccines, and safety.

A DNA vaccine against ERBB2 impairs chemical carcinogenesis in random-bred hamsters

Vaccines against oncoantigens halt early neoplastic lesions in several cancer-prone, genetically engineered mouse models, whereas their ability to prevent chemical carcinogenesis has not been explored. This is a significant issue, as exposure to chemical mutagens is responsible for a substantial percentage of cancers worldwide. Here, we show that the archetypal oncoantigen ERBB2 is transiently overexpressed in Syrian hamsters during the early stages of 7,12-dimethylbenz[α]anthracene (DMBA)-induced oral carcinogenesis. Repeated DNA vaccinations against ERBB2 significantly reduce the number, size, and severity of oral lesions in a manner directly proportional to the anti-ERBB2 antibody response. These results support the prospects of vaccines as a fresh strategy in the management of individuals at risk for exposure to defined carcinogenic agents.