Phase I trial of a recombinant yeast-CEA vaccine (GI-6207) in adults with metastatic CEA-expressing carcinoma

Emerging Frontiers in Colorectal Cancer Therapy: From Targeted Molecules to Immunomodulatory Breakthroughs and Cell-Based Approaches

Colorectal cancer (CRC) is ranked as the second leading cause of cancer-related deaths globally, necessitating urgent advancements in therapeutic approaches. The emergence of groundbreaking therapies, including chimeric antigen receptor-T (CAR-T) cell therapies, oncolytic viruses, and immune checkpoint inhibitors, marks a transformative era in oncology. These innovative modalities, tailored to individual genetic and molecular profiles, hold the promise of significantly enhancing patient outcomes. This comprehensive review explores the latest clinical trials and advancements, encompassing targeted molecular therapies, immunomodulatory agents, and cell-based therapies. By evaluating the strengths, limitations, and potential synergies of these approaches, this research aims to reshape the treatment landscape and improve clinical outcomes for CRC patients, offering new found hope for those who have exhausted conventional options. The culmination of this work is anticipated to pave the way for transformative clinical trials, ushering in a new era of personalized and effective CRC therapy.

Current and Future Trends of Colorectal Cancer Treatment: Exploring Advances in Immunotherapy

Cancer of the colon and rectum (CRC) has been identified among the three most prevalent types of cancer and cancer-related deaths for both sexes. Even though significant progress in surgical and chemotherapeutic techniques has markedly improved disease-free and overall survival rates in contrast to those three decades ago, recent years have seen a stagnation in these improvements. This underscores the need for new therapies aiming to augment patient outcomes. A number of emerging strategies, such as immune checkpoint inhibitors (ICIs) and adoptive cell therapy (ACT), have exhibited promising outcomes not only in preclinical but also in clinical settings. Additionally, a thorough appreciation of the underlying biology has expanded the scope of research into potential therapeutic interventions. For instance, the pivotal role of altered telomere length in early CRC carcinogenesis, leading to chromosomal instability and telomere dysfunction, presents a promising avenue for future treatments. Thus, this review explores the advancements in CRC immunotherapy and telomere-targeted therapies, examining potential synergies and how these novel treatment modalities intersect to potentially enhance each other's efficacy, paving the way for promising future therapeutic advancements.

Carcinoembryonic antigen in the diagnosis, treatment, and follow-up of focal liver lesions

In this editorial review, we comment on the article published in the recent issue of the World Journal of Gastrointestinal Surgery. Carcinoembryonic antigen (CEA) is a fetal glycoprotein and can be secreted in very small amounts from healthy adults after birth. CEA is widely used not only for diagnostic tumor markers but also importantly for the management of some gastrointestinal tumors. The most common clinical use is surveillance for the monitoring of colorectal carcinoma. However, CEA can become elevated in several malign or benign characterized pathologies. Serum CEA level may vary depending on the location of the lesion, whether it metastasizes or not, and its histopathological characteristics. It has been determined that cases with high preoperative CEA have a more aggressive course and the risk of metastasis to the lymph tissue and liver increases. In this editorial review, we focused on evaluating the role of CEA in clinical practice with a holistic approach, including the diagnostic and prognostic significance of CEA in patients with focal liver lesions, the role of CEA in follow-up after definitive surgery, and also hepatic resection for metastasis, and the management of all patients with raised CEA.

Generation of the therapeutic monoclonal antibody NEO-201, derived from a cancer vaccine, which targets human malignancies and immune suppressor cells

INTRODUCTION

Cancer vaccines stimulate the activation of specific humoral and cellular adaptive responses against cancer cells.Antibodies generated post vaccination can be isolated and further selected to develop highly specific and potent monoclonal antibodies (mAbs) against tumor-associated antigens.

AREAS COVERED

This review describes different types of cancer vaccines, the process of the generation of the mAb NEO-201 from the Hollinshead cancer vaccine platform, the characterization of the antigen recognized by NEO-201, the ability of NEO-201 to bind and mediate the killing of cancer cells and immunosuppressive cells (gMDSCs and Tregs) through ADCC and CDC, NEO-201 preclinical and clinical toxicity and efficacy.

EXPERT OPINION

To overcome the problem of poor clinical efficacy of cancer vaccines, due to the activity of immunosuppressive cells, cancer vaccines could be combined with other immunotherapeutics able to deplete immunosuppressive cells. Results from clinical trials, employing NEO-201 alone or in combination with pembrolizumab, showed that durable stabilization of disease after treatment was due to the ability of NEO-201 to target and reduce the percentage of circulating Tregs and gMDSCs.These findings provide compelling support to combine NEO-201 with cancer vaccines to reintegrate their ability to elicit a robust and durable immune adaptive response against cancer.

Harnessing Immunity to Treat Advanced Thyroid Cancer

The incidence of thyroid cancer (TC) has increased over the past 30 years. Although differentiated thyroid cancer (DTC) has a good prognosis in most patients undergoing total thyroidectomy followed by radioiodine therapy (RAI), 5-10% of patients develop metastasis. Anaplastic thyroid cancer (ATC) has a low survival rate and few effective treatments have been available to date. Recently, tyrosine kinase inhibitors (TKIs) have been successfully applied to RAI-resistant or non-responsive TC to suppress the disease. However, TC eventually develops resistance to TKIs. Immunotherapy is a promising treatment for TC, the majority of which is considered an immune-hot malignancy. Immune suppression by TC cells and immune-suppressing cells, including tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells, is complex and dynamic. Negative immune checkpoints, cytokines, vascular endothelial growth factors (VEGF), and indoleamine 2,3-dioxygenase 1 (IDO1) suppress antitumor T cells. Basic and translational advances in immune checkpoint inhibitors (ICIs), molecule-targeted therapy, tumor-specific immunotherapy, and their combinations have enabled us to overcome immune suppression and activate antitumor immune cells. This review summarizes current findings regarding the immune microenvironment, immunosuppression, immunological targets, and immunotherapy for TC and highlights the potential efficacy of immunotherapy.

Colorectal Cancer Immunotherapy: State of the Art and Future Directions

Cancer immunotherapy has become an indispensable mode of treatment for a multitude of solid tumor cancers. Colorectal cancer (CRC) has been one of the many cancer types to benefit from immunotherapy, especially in advanced disease where standard treatment fails to prevent recurrence or results in poor survival. The efficacy of immunotherapy in CRC has not been without challenge, as early clinical trials observed dismal responses in unselected CRC patients treated with checkpoint inhibitors. Many studies and clinical trials have since refined immunotherapies available for CRC, solidifying immunotherapy as a powerful asset for CRC treatment. This review article examines CRC immunotherapies, from their foundation, through emerging avenues for improvement, to future directions.

RNA Vaccines: Yeast as a Novel Antigen Vehicle

In the last decades, technological advances for RNA manipulation enabled and expanded its application in vaccine development. This approach comprises synthetic single-stranded mRNA molecules that direct the translation of the antigen responsible for activating the desired immune response. The success of RNA vaccines depends on the delivery vehicle. Among the systems, yeasts emerge as a new approach, already employed to deliver protein antigens, with efficacy demonstrated through preclinical and clinical trials. β-glucans and mannans in their walls are responsible for the adjuvant property of this system. Yeast β-glucan capsules, microparticles, and nanoparticles can modulate immune responses and have a high capacity to carry nucleic acids, with bioavailability upon oral immunization and targeting to receptors present in antigen-presenting cells (APCs). In addition, yeasts are suitable vehicles for the protection and specific delivery of therapeutic vaccines based on RNAi. Compared to protein antigens, the use of yeast for DNA or RNA vaccine delivery is less established and has fewer studies, most of them in the preclinical phase. Here, we present an overview of the attributes of yeast or its derivatives for the delivery of RNA-based vaccines, discussing the current challenges and prospects of this promising strategy.

CD276 as a Candidate Target for Immunotherapy in Medullary Thyroid Cancer

Medullary thyroid cancer (MTC) is a rare malignancy, and the treatment of metastatic MTC is challenging. In previous work, immune profiling (RNA-Seq) of MTC identified CD276 as a potential target for immunotherapy. CD276 expression was 3-fold higher in MTC cells than in normal tissues. Paraffin blocks from patients with MTC were analyzed by immunohistochemistry to confirm the results of RNA-Seq. Serial sections were incubated with anti-CD276 antibody, and scored according to staining intensity and the percentage of immunoreactive cells. The results showed that CD276 expression was higher in MTC tissues than in controls. A lower percentage of immunoreactive cells correlated with the absence of lateral node metastasis, lower levels of calcitonin after surgery, no additional treatments, and remission. There were statistically significant associations of intensity of immunostaining and percentage of CD276 immunoreactive cells with clinical factors and the course of the disease. These results suggest that targeting this immune checkpoint molecule CD276 could be a promising strategy for the treatment of MTC.

Integrated analysis of transcription factor-mRNA-miRNA regulatory network related to immune characteristics in medullary thyroid carcinoma

Background

Medullary thyroid carcinoma (MTC), a thyroid C cell-derived malignancy, is poorly differentiated and more aggressive than papillary, follicular and oncocytic types of thyroid cancer. The current therapeutic options are limited, with a third of population suffering resistance. The differential gene expression pattern among thyroid cancer subtypes remains unclear. This study intended to explore the exclusive gene profile of MTC and construct a comprehensive regulatory network via integrated analysis, to uncover the potential key biomarkers.

Methods

Multiple datasets of thyroid and other neuroendocrine tumors were obtained from GEO and TCGA databases. Differentially expressed genes (DEGs) specific in MTC were identified to construct a transcription factor (TF)-mRNA-miRNA network. The impact of the TF-mRNA-miRNA network on tumor immune characteristics and patient survival was further explored by single-sample GSEA (ssGSEA) and ESTIMATE algorithms, as well as univariate combined with multivariate analyses. RT-qPCR, cell viability and apoptosis assays were performed for in vitro validation.

Results

We identified 81 genes upregulated and 22 downregulated in MTC but not in other types of thyroid tumor compared to the normal thyroid tissue. According to the L1000CDS2 database, potential targeting drugs were found to reverse the expressions of DEGs, with panobinostat (S1030) validated effective for tumor repression in MTC by in vitro experiments. The 103 DEGs exclusively seen in MTC were involved in signal release, muscle contraction, pathways of neurodegeneration diseases, neurotransmitter activity and related amino acid metabolism, and cAMP pathway. Based on the identified 15 hub genes, a TF-mRNA-miRNA linear network, as well as REST-cored coherent feed-forward loop networks, namely REST-KIF5C-miR-223 and REST-CDK5R2-miR-130a were constructed via online prediction and validation by public datasets and our cohort. Hub-gene, TF and miRNA scores in the TF-mRNA-miRNA network were related to immune score, immune cell infiltration and immunotherapeutic molecules in MTC as well as in neuroendocrine tumor of lung and neuroblastoma. Additionally, a high hub-gene score or a low miRNA score indicated good prognoses of neuroendocrine tumors.

Conclusion

The present study uncovers underlying molecular mechanisms and potential immunotherapy-related targets for the pathogenesis and drug discovery of MTC.

Standardization and Key Aspects of the Development of Whole Yeast Cell Vaccines

In the context of vaccine development, improving antigenic presentation is critical for the activation of specific immune responses and the success of immunization, in addition to selecting an appropriate target. In this sense, different strategies have been developed and improved. Among them is the use of yeast cells as vehicles for the delivery of recombinant antigens. These vaccines, named whole yeast vaccines (WYVs), can induce humoral and cellular immune responses, with the additional advantage of dispensing with the use of adjuvants due to the immunostimulatory properties of their cell wall components. However, there are some gaps in the methodologies for obtaining and validating recombinant strains and vaccine formulations. The standardization of these parameters is an important factor for WYVs approval by regulatory agencies and, consequently, their licensing. This review aimed to provide an overview of the main parameters to consider when developing a yeast-based vaccine, addressing some available tools, and highlighting the main variables that can influence the vaccine production process.

How far have we explored fungi to fight cancer?

The use of fungal cultures have been well documented in human history. Although its used in healthcare, like penicillin and statins, have saved countless of lives, but there is still no fungal products that are specifically indicated for cancers. Research into fungal-derived materials to curb cancers in the recent decades have made a considerable progress in terms of drug delivery vehicles, anticancer active ingredients and cancer immunotherapy. Various parts of the organisms have successfully been exploited to achieve specific tasks. Apart from the identification of novel anticancer compound from fungi, its native capsular structure can also be used as drug cargo to achieve higher oral bioavailability. This review summarises the anticancer potential of fungal-derived materials, highlighting the role of capsular polysaccharides, proteins, and other structures in variety of innovative utilities to fit the current pharmaceutical technology. Many bioactive compounds isolated from fungi have also been formulated into nanoparticles to achieve greater anticancer activity. The progress of fungal compounds and their analogues in clinical trials is also highlighted. In addition, the potential of various fungal species to be developed for anticancer immunotherapy are also discussed.

Colorectal cancer vaccines: The current scenario and future prospects

Colorectal cancer (CRC) is one of the most common cancers worldwide. Current therapies such as surgery, chemotherapy, and radiotherapy encounter obstacles in preventing metastasis of CRC even when applied in combination. Immune checkpoint inhibitors depict limited effects due to the limited cases of CRC patients with high microsatellite instability (MSI-H). Cancer vaccines are designed to trigger the elevation of tumor-infiltrated lymphocytes, resulting in the intense response of the immune system to tumor antigens. This review briefly summarizes different categories of CRC vaccines, demonstrates the current outcomes of relevant clinical trials, and provides particular focus on recent advances on nanovaccines and neoantigen vaccines, representing the trend and emphasis of CRC vaccine development.

Medullary thyroid carcinoma: a narrative historical review

INTRODUCTION

Sporadic or hereditary medullary thyroid carcinoma (MTC) is an uncommon thyroid malignancy arising from calcitonin secreting parafollicular C cells. Interestingly, MTC and calcitonin were distinct entities that were discovered independently yet concurrently, and their association was unknown.

AREAS COVERED

This review aims to present a historical review of the evolution of our understanding of MTC and its tumor marker calcitonin to highlight the prominent individuals that influenced and shaped our knowledge of this uncommon thyroid cancer type up to the dawn of the 21^st century. An overview of all published reports of novel research and work summarizing important findings for MTC and calcitonin was carried out.

EXPERT OPINION

Surgery remains the cornerstone of treatment for localized MTC. However, several new treatment options are either available or in development for advanced or metastatic MTC, including several novel small molecules targeting oncogenic RET and peptide receptor radionuclide therapy, immunotherapy, radioimmunotherapy, and radiofrequency ablation. In the near future, these novel treatments hold promise for therapy of this very distinct thyroid cancer type.

Oral Administration of Probiotics Reduces Chemotherapy-Induced Diarrhea and Oral Mucositis: A Systematic Review and Meta-Analysis

Background

Chemotherapy generally causes serious diarrhea and oral mucositis in cancer patients, and subsequently affects treatment. Oral administration of probiotics provides a therapeutic choice to address these limitations. This study aims to conduct a systematic review and meta-analysis on the efficacy of oral probiotic use in the management of the chemotherapy-induced adverse reactions, and to summarize the mechanisms underlying the action.

Methods

We searched PubMed, Embase, ClinicalTrials.gov, and Web of Science from the start of the study to its completion on Dec. 31, 2021. Risk of bias was assessed using Cochrane Collaboration's Tool. Statistical analysis of the acquired data was performed via the RevMan and the Stata Statistical Software. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO registration number: CRD42020220650).

Results

Twelve randomized controlled trials including 1,013 patients were recruited and analyzed via the standard procedure of meta-analysis. In contrast to the control group, orally taking probiotics significantly decreased the risk of chemotherapy-induced diarrhea (≥ 1 grade) (RR = 0.70; 95% Cl: 0.56, 0.88; P = 0.002) and oral mucositis (≥ 1 grade) (RR: 0.84; 95% Cl: 0.78, 0.91; P < 0.00001) at all grades. Further analysis found that severe diarrhea (≥ 2 grades) (RR: 0.50; 95% Cl: 0.32, 0.78; P = 0.002) and severe oral mucositis also significantly declined (≥ 3 grades) (RR: 0.66; 95% Cl: 0.55, 0.79; P < 0.00001) after oral probiotic use. Interestingly, the beneficial effects of probiotics displayed statistically significant only in Asian patients. Importantly, the more species of bacteria they took, the lower the incidences of the adverse reactions occurred. We used Egger's test P value to confirm that there is no publication bias.

Conclusions

This meta-analysis demonstrated that orally administrated probiotics has a potential to decrease chemotherapy-induced diarrhea and oral mucositis incidences. However, the efficacy of oral probiotic use against the adverse reactions needs to be further verified through more clinical trials, and the species and number of probiotics have to be optimized and standardized prior to clinical applications.

Systematic Review Registration

https://www.crd.york.ac.uk, identifier: 220650.

Tumor associated macrophage and microbe: The potential targets of tumor vaccine delivery

The occurrence and development of tumors depend on the tumor microenvironment (TME), which is made of various immune cells, activated fibroblasts, basement membrane, capillaries, and extracellular matrix. Tumor associated macrophages (TAMs) and microbes are important components in TME. Tumor cells can recruit and educate TAMs and microbes, and the hijacked TAMs and microbes can promote the progression of tumor reciprocally. Tumor vaccine delivery remodeling TME by targeting TAM and microbes can not only enhance the specificity and immunogenicity of antigens, but also contribute to the regulation of TME. Tumor vaccine design benefits from nanotechnology which is a suitable platform for antigen and adjuvant delivery to catalyze new candidate vaccines applying to clinical therapy at unparalleled speed. In view of the characteristics and mechanisms of TME development, vaccine delivery targeting and breaking the malignant interactions among tumor cells, TAMs, and microbes may serve as a novel strategy for tumor therapy.

A pilot trial of vaccination with Carcinoembryonic antigen and Her2/neu peptides in advanced colorectal cancer

Checkpoint-blockade therapy (CBT) is approved for select colorectal cancer (CRC) patents, but additional immunotherapeutic options are needed. We hypothesized that vaccination with carcinoembryonic antigen (CEA) and Her2/neu (Her2) peptides would be immunogenic and well tolerated by participants with advanced CRC. A pilot clinical trial (NCT00091286) was conducted in HLA-A2⁺ or -A3⁺ Stage IIIC-IV CRC patients. Participants were vaccinated weekly with CEA and Her2 peptides plus tetanus peptide and GM-CSF emulsified in Montanide ISA-51 adjuvant for 3 weeks. Adverse events (AEs) were recorded per NIH Common Terminology Criteria for Adverse Events version 3. Immunogenicity was evaluated by interferon-gamma ELISpot assay of in vitro sensitized peripheral blood mononuclear cells and lymphocytes from the sentinel immunized node. Eleven participants were enrolled and treated; one was retrospectively found to be ineligible due to HLA type. All 11 participants were included in AEs and survival analyses, and the 10 eligible participants were evaluated for immunogenicity. All participants reported AEs: 82% were Grade 1-2, most commonly fatigue or injection site reactions. Two participants (18%) experienced treatment-related dose-limiting Grade 3 AEs; both were self-limiting. Immune responses to Her2 or CEA peptides were detected in 70% of participants. Median overall survival (OS) was 16 months; among those enrolled with no evidence of disease (n = 3), median OS was not reached after 10 years of follow-up. These data demonstrate that vaccination with CEA or Her2 peptides is well tolerated and immunogenic. Further study is warranted to assess potential clinical benefits of vaccination in advanced CRC either alone or in combination with CBT.

A Brief Introduction to Current Cancer Gene Therapy

Gene therapy has started in the late 1980s as novel, clinically applicable therapeutic option. It revolutionized the treatment of genetic diseases with the initial intent to repair or replace defective genes. Gene therapy has been adapted for treatment of malignant diseases to improve the outcome of cancer patients. In fact, cancer gene therapy has rapidly gained great interest and evolved into a research field with highest proportion of research activities in gene therapy. In this context, cancer gene therapy has long entered translation into clinical trials and therefore more than two-thirds of all gene therapy trials worldwide are aiming at the treatment of cancer disease using different therapeutic strategies. During the decades in cancer gene therapy, tremendous knowledge has accumulated. This led to significant improvements in vector design, transgene repertoire, more targeted interventions, use of novel gene therapeutic technologies such as CRISPR/Cas, sleeping beauty vectors, and development of effective cancer immunogene therapies. In this chapter, a brief overview of current key developments in cancer gene therapy is provided to gain insights into the recent directions in research as well as in clinical application of cancer gene therapy.

A review on the advances and challenges of immunotherapy for head and neck cancer

Head and neck cancer (HNC), which includes lip and oral cavity, larynx, nasopharynx, oropharynx, and hypopharynx malignancies, is one of the most common cancers worldwide. Due to the interaction of tumor cells with immune cells in the tumor microenvironment, immunotherapy of HNCs, along with traditional treatments such as chemotherapy, radiotherapy, and surgery, has attracted much attention. Four main immunotherapy strategies in HNCs have been developed, including oncolytic viruses, monoclonal antibodies, chimeric antigen receptor T cells (CAR-T cells), and therapeutic vaccines. Oncorine (H101), an approved oncolytic adenovirus in China, is the pioneer of immunotherapy for the treatment of HNCs. Pembrolizumab and nivolumab are mAbs against PD-L1 that have been approved for recurrent and metastatic HNC patients. To date, several clinical trials using immunotherapy agents and their combination are under investigation. In this review, we summarize current the interaction of tumor cells with immune cells in the tumor microenvironment of HNCs, the main strategies that have been applied for immunotherapy of HNCs, obstacles that hinder the success of immunotherapies in patients with HNCs, as well as solutions for overcoming the challenges to enhance the response of HNCs to immunotherapies.

Pichia pastoris displaying ZIKV protein epitopes from the Envelope and NS1 induce in vitro immune activation

The severe consequences of ZIKV infection and its emergence and re-emergence in several countries have boosted vaccines' development. Yeasts such as Pichia pastoris has been widely employed as antigen carriers for immunization against infectious agents. Components of the yeast cell wall have immunostimulatory properties, and recombinant antigens can be anchored to the cell surface to enhance the presentation to the immune system. Here we aimed at producing and anchoring ZIKV proteins in the P. pastoris surface as a vaccine approach. Expression cassettes were designed with epitopes of the Envelope and NS1 proteins. Immunofluorescence microscopy confirmed the anchoring of recombinant proteins. Yeasts' ability to stimulate immune cells was evaluated in vitro by incubation with lymphocytes and monocytes isolated from mouse spleen. P. pastoris expressing EnvNS1 epitopes promoted increased levels of IL-6, IL-10, and TNF-α cytokines and an increase in the number of CD4+, CD8+, and CD16+ lymphocytes, similarly to ZIKV. This profile is indicative of the activation of immunological cells and suggests an immunogenic potential of the proposed yeast vaccines against ZIKV, reinforcing the possibility of P. pastoris as adjuvant and carrier of antigens.

Multiple endocrine neoplasia type 2: A reveiw

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

Role of targeted immunotherapy for pancreatic ductal adenocarcinoma (PDAC) treatment: An overview

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest solid tumors with a high mortality rate and poor survival rate. Depending on the tumor stage, PDAC is either treated by resection surgery, chemotherapies, or radiotherapies. Various chemotherapeutic agents have been used to treat PDAC, alone or in combination. Despite the combinations, chemotherapy exhibits many side-effects leading to an increase in the toxicity profile amongst the PDAC patients. Additionally, these standard chemotherapeutic agents have only a modest impact on patient survival due to their limited efficacy. PDAC was previously considered as an immunologically silent malignancy, but recent findings have demonstrated that effective immune-mediated tumor cell death can be used for its treatment. PDAC is characterized by an immunosuppressive tumor microenvironment accompanied by the major expression of myeloid-derived suppressor cells (MDSC) and M2 tumor-associated macrophages. In contrast, the expression of CD8⁺ T cells is significantly low. Additionally, infiltration of mast cells in PDAC correlates with the poor prognosis. Immunotherapeutic agents target the immunity mediators and empower them to suppress the tumor and effectively treat PDAC. Different targets are studied and exploited to induce an antitumor immune response in PDAC patients. In recent times, site-specific delivery of immunotherapeutics also gained attention among researchers to effectively treat PDAC. In the present review, existing immunotherapies for PDAC treatment along with their limitations are addressed in detail. The review also includes the pathophysiology, traditional strategies and significance of targeted immunotherapies to combat PDAC effectively. Separately, the identification of ideal targets for the targeted therapy of PDAC is also reviewed exhaustively. Additionally, the review also addresses the applications of targeted immunotherapeutics like checkpoint inhibitors, adoptive T-cell therapy etc.

Update on Targeted Therapy in Medullary Thyroid Cancer

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor that accounts for 2-4% of all thyroid cancers. All inherited MTC and approximately 50% of sporadic cases are driven by mutations in the REarranged during Transfection (RET) proto-oncogene. The recent expansion of the armamentarium of RET-targeting tyrosine kinase inhibitors (TKIs) has provided effective options for systemic therapy for patients with metastatic and progressive disease. However, patients that develop resistant disease as well as those with other molecular drivers such as RAS have limited options. An improved understanding of mechanisms of resistance to TKIs as well as identification of novel therapeutic targets is needed to improve outcomes for patients with MTC.

New Horizons: Emerging Therapies and Targets in Thyroid Cancer

The treatment of patients with progressive metastatic follicular cell-derived and medullary thyroid cancers that do not respond to standard therapeutic modalities presents a therapeutic challenge. As a deeper understanding of the molecular drivers for these tumors has occurred and more potent and specific compounds are developed, the number of Food and Drug Administration (FDA)-approved treatments for thyroid cancer has expanded. In addition, with the advent of disease-agnostic target-directed FDA approvals an ever-broadening number of therapeutic options are available for clinicians and patients. However, to date, complete remissions are rare, the average durations of response are relatively modest, and toxicities are common. These factors accentuate the need for further understanding of the mechanisms of resistance that result in treatment failures, the development of biomarkers that can improve patient selection for treatment earlier in the disease process, and the continued need for new therapeutic strategies. In this article, recent approvals relevant to thyroid cancer will be discussed along with selected new potential avenues that might be exploited for future therapies.

Immunotherapy for advanced thyroid cancers - rationale, current advances and future strategies

In the past decade, the field of cancer immunotherapy has been revolutionized by immune checkpoint blockade (ICB) technologies. Success across a broad spectrum of cancers has led to a paradigm shift in therapy for patients with advanced cancer. Early data are now accumulating in progressive thyroid cancers treated with single-agent ICB therapies and combination approaches that incorporate ICB technologies. This Review discusses our current knowledge of the immune response in thyroid cancers, the latest and ongoing immune-based approaches, and the future of immunotherapies in thyroid cancer. Physiologically relevant preclinical mouse models and human correlative research studies will inform development of the next stage of immune-based therapies for patients with advanced thyroid cancer.

Therapeutic vaccines for colorectal cancer: The progress and future prospect

Cancer vaccines are usually derived from the patient's tumor cells or the antigens found on their surface, which may help the immune system to identify and kill these malignant cells. Current focus of many researches is designing vaccines with the hope of triggering the immune system to attack cancer cells in a more effective, reliable and safe manner. Although colorectal cancer (CRC) is recognized as the third leading cause of death by cancer, but significant advances in therapy strategies have been made in recent years, including cancer vaccine. In this review, we present various vaccine platforms that have been used in the border battle against CRC, some of which have been approved for clinical use and some are in late-stage clinical trials. Until September 2020 there is approximately 1940 clinical trials of cancer vaccines on patients with different cancer types, and also many more trials are in the planning stages, which makes it the most important period of therapeutic cancer vaccines studies in the history of the immunotherapy. In cancer vaccines clinical trials, there are several considerations that must be taken into account including engineering of antigen-presenting cells, potential toxicity of antigenic areas, pharmacokinetics and pharmacodynamics of vaccines, and monitoring of the patients' immune response. Therefore, the need to overcome immunosuppression mechanisms/immune tolerance is a critical step for the success of introducing therapeutic vaccines into the widely used drugs on market. In this way, better understanding of neoantigens, tumor immune surveillance escape mechanisms and host-tumor interactions are required to develop more effective and safe cancer vaccines.

Colorectal Cancer Immunotherapy: Options and Strategies

Colorectal cancer is the third most common cancer in the world with increasing incidence and mortality rates globally. Standard treatments for colorectal cancer have always been surgery, chemotherapy and radiotherapy which may be used in combination to treat patients. However, these treatments have many side effects due to their non-specificity and cytotoxicity toward any cells including normal cells that are growing and dividing. Furthermore, many patients succumb to relapse even after a series of treatments. Thus, it is crucial to have more alternative and effective treatments to treat CRC patients. Immunotherapy is one of the new alternatives in cancer treatment. The strategy is to utilize patients' own immune systems in combating the cancer cells. Cancer immunotherapy overcomes the issue of specificity which is the major problem in chemotherapy and radiotherapy. The normal cells with no cancer antigens are not affected. The outcomes of some cancer immunotherapy have been astonishing in some cases, but some which rely on the status of patients' own immune systems are not. Those patients who responded well to cancer immunotherapy have a better prognostic and better quality of life.

HNSCC: Tumour Antigens and Their Targeting by Immunotherapy

Head and neck squamous cell carcinomas (HNSCC) are a heterogeneous group of malignant tumours typically caused by alcohol and tobacco consumption, although an increasing number of HNSCC arise due to persistent infection with high-risk human papilloma virus (HPV). The treatment of HNSCC remains challenging, and the first-line setting is focused on surgery and chemoradiotherapy. A substantial proportion of HNSCC patients die from their disease, especially those with recurrent and metastatic disease. Among factors linked with good outcome, immune cell infiltration appears to have a major role. HPV-driven HNSCC are often T-cell rich, reflecting the presence of HPV antigens that are immunogenic. Tumour-associated antigens that are shared between patients or that are unique to an individual person may also induce varying degrees of immune response; studying these is important for the understanding of the interaction between the host immune system and the cancer. The resulting knowledge is critical for the design of better immunotherapies. Key questions are: Which antigens lead to an adaptive immune response in the tumour? Which of these are exploitable for immunotherapy? Here, we review the current thinking regarding tumour antigens in HNSCC and what has been learned from early phase clinical trials.

Comprehensive Immune Profiling of Medullary Thyroid Cancer

Background: Despite advances in targeted kinase inhibitor development for patients with medullary thyroid cancer (MTC), most patients develop resistance and would benefit from alternative approaches. Immune-based therapies are now considered for patients with progressive MTC. This study is the first comprehensive assessment of the immune milieu, immune-suppressive molecules, and potential tumor antigens in patients with MTC. Methods: Primary and/or regionally metastatic tumor tissues from 46 patients with MTC were screened for immune infiltrates by using standard immunohistochemistry (IHC) and further analyzed by multispectral imaging for T cell and myeloid markers. RNASeq expression profiling was performed in parallel. RNASeq, targeted sequencing, and IHC techniques identified cancer-associated mutations and MTC-enriched proteins. Results: Organized immune infiltration was observed in 49% and 90% of primary and metastatic tumors, respectively. CD8⁺ cells were the dominant T cell subtype in most samples, while CD163⁺ macrophages were most frequent among myeloid infiltrates. PD-1⁺ T cells were evident in 24% of patients. Myeloid subsets were largely major histocompatibility complex II (MHCII^-), suggesting a dysfunctional phenotype. Expression profiling confirmed enrichment in T cell, macrophage, and inflammatory profiles in a subset of samples. PD-L1 was expressed at low levels in a small subset of patients, while the immune regulatory molecules CD155 and CD47 were broadly expressed. Calcitonin, GRP, HIST1H4E, NOMO3, and NPIPA2 were highly and specifically expressed in MTC. Mutations in tumor suppressors, PTEN and p53, and mismatch repair genes, MSH2 and MSH6, may be relevant to disease progression and antigenicity. Conclusions: This study suggests that MTC is a more immunologically active tumor that has been previously reported. Patients with advanced MTC should be screened for targetable antigens and immune checkpoints to determine their eligibility for current clinical trials. Additional studies are necessary to fully characterize the antigenic potential of MTC and may encourage the development of adoptive T cells therapies for this rare tumor.

Updates on the Management of Thyroid Cancer

The diagnostic modalities, stratification tools, and treatment options for patients with thyroid cancer have rapidly evolved since the development of the American Thyroid Association (ATA) guidelines in 2015. This review compiles newer concepts in diagnosis, stratification tools and treatment options for patients with differentiated thyroid cancer (DTC), medullary thyroid carcinoma (MTC) and anaplastic thyroid cancer (ATC). Newer developments apply precision medicine in thyroid cancer patients to avoid over-treatment in low risk disease and under-treatment in high risk disease. Among novel patient-tailored therapies are selective RET inhibitors that have shown efficacy in the treatment of MTC with limited systemic toxicity compared with non-specific tyrosine kinase inhibitors. The combination of BRAF and MEK inhibitors have revolutionized management of BRAF V600E mutant ATC. Several immunotherapeutic agents are being actively investigated in the treatment of all forms of thyroid cancer. In this review, we describe the recent advances in the diagnosis and management of DTC, MTC, and ATC, with an emphasis on novel treatment modalities.

Update on the Treatment of Medullary Thyroid Carcinoma in Patients with Multiple Endocrine Neoplasia Type 2

Medullary Thyroid Carcinoma (MTC) is a rare neuroendocrine cancer that accounts for 1-2% of thyroid cancers in the United States (U.S.). While most cases are sporadic, 25% of MTC cases are hereditary. These hereditary cases occur in the setting of Multiple Endocrine Neoplasia Type 2A (MEN2A) or 2B (MEN2B) driven by mutations in the Rearranged during Transfection RET proto-oncogene. This article discusses hereditary MTC in the setting of MEN2 and the treatment options available for it. The first line treatment for this disease is typically a total thyroidectomy and tyrosine kinase inhibitors. Two tyrosine kinase inhibitors, vandetanib and cabozantinib, have been approved for treatment of advanced MTC, but options beyond those are limited. However, several promising treatments are being studied, which are discussed in this review.

Novel Targeted Therapies for Metastatic Thyroid Cancer-A Comprehensive Review

The knowledge on thyroid cancer biology has grown over the past decade. Thus, diagnostic and therapeutic strategies to manage thyroid cancer are rapidly evolving. With new insights into tumor biology and cancer genetics, several novel therapies have been approved for the treatment of thyroid cancer. Tyrosine kinase inhibitors (TKIs), such as lenvatinib and sorafenib, have been successfully utilized for the treatment of radioactive iodine (RAI)-refractory metastatic differentiated thyroid cancer (DTC). In addition, pretreatment with mitogen-activated protein kinase (MAPK) inhibitors (trametinib and selumetinib) has been shown to restore RAI avidity in previously RAI-refractory DTCs. Local therapies, such as external beam radiation and radiofrequency/ethanol ablation, have also been employed for treatment of DTC. Vandetanib and cabozantinib are the two TKIs currently approved by the Food and Drug Administration (FDA) for the treatment of medullary thyroid cancer (MTC). Other novel therapies, such as peptide receptor radionuclide therapy and carcinoembryonic antigen (CEA) vaccine, have also been utilized in treating MTC. Ongoing trials on selective rearranged-during-transfection (RET) protooncogene inhibitors, such as LOXO-292 and BLU-667, have demonstrated promising results in the treatment of metastatic MTC resistant to non-selective TKIs. The FDA-approved BRAF/MEK inhibitor combination of dabrafenib and trametinib has revolutionized treatment of BRAFV600E mutation positive anaplastic thyroid cancer. Several other emerging classes of medications, such as gene fusion inhibitors and immune checkpoint inhibitors, are being actively investigated in several clinical trials. In this review, we describe the molecular landscape of thyroid cancer and novel targeted therapies and treatment combinations available for the treatment of metastatic thyroid cancer.

A Case Report of Sequential Use of a Yeast-CEA Therapeutic Cancer Vaccine and Anti-PD-L1 Inhibitor in Metastatic Medullary Thyroid Cancer

Medullary thyroid cancer (MTC) accounts for ~4% of all thyroid malignancies. MTC derives from the neural crest and secretes calcitonin (CTN) and carcinoembryonic antigen (CEA). Unlike differentiated thyroid cancer, MTC does not uptake iodine and I-131 RAI (radioactive iodine) treatment is ineffective. Patients with metastatic disease are candidates for FDA-approved agents with either vandetanib or cabozantinib; however, adverse effects limit their use. There are ongoing trials exploring the role of less toxic immunotherapies in patients with MTC. We present a 61-year-old male with the diagnosis of MTC and persistent local recurrence despite multiple surgeries. He was started on sunitinib, but ultimately its use was limited by toxicity. He then presented to the National Cancer Institute (NCI) and was enrolled on a clinical trial with heat-killed yeast-CEA vaccine (NCT01856920) and his calcitonin doubling time improved in 3 months. He then came off vaccine for elective surgery. After surgery, his calcitonin was rising and he enrolled on a phase I trial of avelumab, a programmed death-ligand 1 (PD-L1) inhibitor (NCT01772004). Thereafter, his calcitonin decreased > 40% on 5 consecutive evaluations. His tumor was subsequently found to express PD-L1. CEA-specific T cells were increased following vaccination, and a number of potential immune-enhancing changes were noted in the peripheral immunome over the course of sequential immunotherapy treatment. Although calcitonin declines do not always directly correlate with clinical responses, this response is noteworthy and highlights the potential for immunotherapy or sequential immunotherapy in metastatic or unresectable MTC.

Immunotherapeutic Approaches for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) originating from the cells of the colon or rectum has a high mortality rate worldwide. Numerous attempts have been made to raise the overall survival rates of CRC patients. It is well-known that the development of malignant neoplasms is accompanied by suppression of the immune system, which is likely the cause for the failure of standard treatment methods. Immune response has long been an issue of great interest in cancer therapy and anti-tumor immunity that consider the development of immunotherapeutic antitumor methods resulting in the immune system activation as an important issue. This review discusses main immunotherapeutic approaches available for the CRC treatment.

Yeast-based vaccines: New perspective in vaccine development and application

In presently licensed vaccines, killed or attenuated organisms act as a source of immunogens except for peptide-based vaccines. These conventional vaccines required a mass culture of associated or related organisms and long incubation periods. Special requirements during storage and transportation further adds to the cost of vaccine preparations. Availability of complete genome sequence, well-established genetic, inherent natural adjuvant and non-pathogenic nature of yeast species viz. Saccharomyces cerevisiae, Pichia pastoris makes them an ideal model system for the development of vaccines both for public health and for on-farm consumption. In this review, we compile the work in this emerging field during last two decades with major emphases on S. cerevisiae and P. pastoris which are routinely used worldwide for expression of heterologous proteins with therapeutic value against infectious diseases along with possible use in cancer therapy. We also pointed towards the developments in use of whole recombinant yeast, yeast surface display and virus-like particles as a novel strategy in the fight against infectious diseases and cancer along with other aspects including suitability of yeast in vaccines preparations, yeast cell wall component as an immune stimulator or modulator and present status of yeast-based vaccines in clinical trials.

Investigating the long-term stability of protein immunogen(s) for whole recombinant yeast-based vaccines

Even today vaccine(s) remains a mainstay in combating infectious diseases. Many yeast-based vaccines are currently in different phases of clinical trials. Despite the encouraging results of whole recombinant yeast and yeast display, the systematic study assessing the long-term stability of protein antigen(s) in yeast cells is still missing. Therefore, in the present study, I investigate the stability of heterologous protein antigen in the cellular environment of Saccharomyces cerevisiae through Escherichia coli surface protein (major curlin or CsgA). Present biochemical data showed that the stationary-phase yeast cells were able to keep the antigen stable for almost 1 year when stored at 2°C-8°C and 23°C-25°C. Further, iTRAQ-based quantitative proteomics of yeast whole cell lysate showed that the level of heterologous fusion protein was low in cells stored at 23°C-25°C compared to those at 2°C-8°C. In the end, I also proposed a workable strategy to test the integrity or completeness of heterologous protein in the yeast cell. I believe that the observations made in the present study will be really encouraging for those interested in the development of a whole recombinant yeast-based vaccine(s).

Immunotherapy: Pancreatic Cancer and Extrahepatic Biliary Tract Cancer

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

The role of hepatic macrophages in liver metastasis

The liver is a major target organ for metastasis of both gastrointestinal and extra-gastrointestinal cancers. Due to its frequently inoperable nature, liver metastasis represents a leading cause of cancer-associated death worldwide. In the past years, the pivotal role of the immune system in this process is being increasingly recognised. In particular, the role of the hepatic macrophages, both recruited monocyte-derived macrophages (Mo-Mfs) and tissue-resident Kupffer cells (KCs), has been shown to be more versatile than initially imagined. However, the lack of tools to easily distinguish between these two macrophage populations has hampered the assignment of particular functionalities to specific hepatic macrophage subsets. In this Review, we highlight the most remarkable findings regarding the origin and functions of hepatic macrophage populations, and we provide a detailed description of their distinct roles in the different phases of the liver metastatic process.

Strategies for Increasing Pancreatic Tumor Immunogenicity

Immunotherapy has changed the standard of care for multiple deadly cancers, including lung, head and neck, gastric, and some colorectal cancers. However, single-agent immunotherapy has had little effect in pancreatic ductal adenocarcinoma (PDAC). Increasing evidence suggests that the PDAC microenvironment is comprised of an intricate network of signals between immune cells, PDAC cells, and stroma, resulting in an immunosuppressive environment resistant to single-agent immunotherapies. In this review, we discuss differences between immunotherapy-sensitive cancers and PDAC, the complex interactions between PDAC stroma and suppressive tumor-infiltrating cells that facilitate PDAC development and progression, the immunologic targets within these complex networks that are druggable, and data supporting combination drug approaches that modulate multiple PDAC signals, which should lead to improved clinical outcomes. Clin Cancer Res; 23(7); 1656-69. ©2017 AACRSee all articles in this CCR Focus section, "Pancreatic Cancer: Challenge and Inspiration."

Immunotherapy in colorectal cancer: for the select few or all?

Over the past few years, the role of immunotherapy in colorectal cancer (CRC) has expanded, specifically in subsets of CRC with microsatellite instability (MSI) for which newer agents, such as programmed death-1 (PD-1) inhibitors, are efficacious. While other immunotherapeutic agents are more immature in development, they have the potential to enhance the efficacy of PD-1 inhibitors and play a role in the treatment algorithm for all subsets of CRC patients. In this review, we will discuss immunotherapeutic agents in development in patients with CRC. We will review the later phase studies that elucidate the role of immunotherapy in CRC and provide hope for changing the treatment paradigm for CRC in the future.

Trial watch: DNA-based vaccines for oncological indications

DNA-based vaccination is a promising approach to cancer immunotherapy. DNA-based vaccines specific for tumor-associated antigens (TAAs) are indeed relatively simple to produce, cost-efficient and well tolerated. However, the clinical efficacy of DNA-based vaccines for cancer therapy is considerably limited by central and peripheral tolerance. During the past decade, considerable efforts have been devoted to the development and characterization of novel DNA-based vaccines that would circumvent this obstacle. In this setting, particular attention has been dedicated to the route of administration, expression of modified TAAs, co-expression of immunostimulatory molecules, and co-delivery of immune checkpoint blockers. Here, we review preclinical and clinical progress on DNA-based vaccines for cancer therapy.

Phase I Study of a Poxviral TRICOM-Based Vaccine Directed Against the Transcription Factor Brachyury

Purpose: The transcription factor brachyury has been shown in preclinical studies to be a driver of the epithelial-to-mesenchymal transition (EMT) and resistance to therapy of human tumor cells. This study describes the characterization of a Modified Vaccinia Ankara (MVA) vector-based vaccine expressing the transgenes for brachyury and three human costimulatory molecules (B7.1, ICAM-1, and LFA-3, designated TRICOM) and a phase I study with this vaccine.Experimental Design: Human dendritic cells (DC) were infected with MVA-brachyury-TRICOM to define their ability to activate brachyury-specific T cells. A dose-escalation phase I study (NCT02179515) was conducted in advanced cancer patients (n = 38) to define safety and to identify brachyury-specific T-cell responses.Results: MVA-brachyury-TRICOM-infected human DCs activated CD8⁺ and CD4⁺ T cells specific against the self-antigen brachyury in vitro No dose-limiting toxicities were observed due to vaccine in cancer patients at any of the three dose levels. One transient grade 3 adverse event (AE) possibly related to vaccine (diarrhea) resolved without intervention and did not recur with subsequent vaccine. All other AEs related to vaccine were transient and ≤grade 2. Brachyury-specific T-cell responses were observed at all dose levels and in most patients.Conclusions: The MVA-brachyury-TRICOM vaccine directed against a transcription factor known to mediate EMT can be administered safely in patients with advanced cancer and can activate brachyury-specific T cells in vitro and in patients. Further studies of this vaccine in combination therapies are warranted and planned. Clin Cancer Res; 23(22); 6833-45. ©2017 AACR.

Review on the immunotherapy strategies against metastatic colorectal carcinoma

Colorectal cancer (CRC) is one of the most common malignancies throughout the world and the leading cause of cancer-related mortality in Western countries. Recent progress in CRC treatment options, such as surgery, chemotherapy, radiotherapy and target therapy, has improved the prognosis, but advanced disease with recurrence or distant metastasis is usually incurable and has an unfavorable prognosis. The introduction of immunotherapy-associated strategies, both active and passive, to the treatment of CRC aims to overcome the limits of classical treatments. We review the state of the art for CRC with respect to different immunotherapeutic approaches, such as the use of cancer vaccines and/or adoptive cellular therapy, their most current advances and limitations and perspectives for further improvements.

Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines

INTRODUCTION

Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

Leveraging the immune system to treat advanced thyroid cancers

Inflammation has long been associated with the thyroid and with thyroid cancers, raising seminal questions about the role of the immune system in the pathogenesis of advanced thyroid cancers. With a growing understanding of dynamic tumour-immune cell interactions and the mechanisms by which tumour cells evade antitumour immunity, the field of cancer immunotherapy has been revolutionised. In this Review, we provide evidence to support the presence of an antitumour immune response in advanced thyroid cancers linked to cytotoxic T cells and NK cells. This antitumour response, however, is likely blunted by the presence of immunosuppressive pathways within the microenvironment, facilitated by tumour-associated macrophages or increased expression of negative regulators of cytotoxic T-cell function. Current and future efforts to incorporate immune-based therapies into existing tumour cell or endothelial-derived therapies-eg, with kinase inhibitors targeting tumour-associated macrophages or antibodies blocking negative regulators on T cells-could provide improved and durable responses for patients with disease that is otherwise refractory to treatment.

The Roles of Carcinoembryonic Antigen in Liver Metastasis and Therapeutic Approaches

Metastasis is a highly complicated and sequential process in which primary cancer spreads to secondary organic sites. Liver is a well-known metastatic organ from colorectal cancer. Carcinoembryonic antigen (CEA) is expressed in most gastrointestinal, breast, and lung cancer cells. Overexpression of CEA is closely associated with liver metastasis, which is the main cause of death from colorectal cancer. CEA is widely used as a diagnostic and prognostic tumor marker in cancer patients. It affects many steps of liver metastasis from colorectal cancer cells. CEA inhibits circulating cancer cell death. CEA also binds to heterogeneous nuclear RNA binding protein M4 (hnRNP M4), a Kupffer cell receptor protein, and activates Kupffer cells to secrete various cytokines that change the microenvironments for the survival of colorectal cancer cells in the liver. CEA also activates cell adhesion-related molecules. The close correlation between CEA and cancer has spurred the exploration of many CEA-targeted approaches as anticancer therapeutics. Understanding the detailed functions and mechanisms of CEA in liver metastasis will provide great opportunities for the improvement of anticancer approaches against colorectal cancers. In this report, the roles of CEA in liver metastasis and CEA-targeting anticancer modalities are reviewed.

Yeast-mediated mRNA delivery polarizes immuno-suppressive macrophages towards an immuno-stimulatory phenotype

Macrophages have increasingly gained interest as a therapeutic target since they represent an integral component of the tumor microenvironment. In fact, M2 macrophage accumulation in solid tumors is associated with poor prognosis and therapy failure. Therefore, reprogramming M2 macrophages towards an M1 phenotype with anti-tumor activity by gene therapy represents a promising therapeutic approach. Herein, we describe recombinant Saccharomyces cerevisiae as a novel gene delivery vehicle for primary human macrophages. Opsonized S. cerevisiae was taken up efficiently by M2 macrophages and initiated the expression of pro-inflammatory cytokines. Recombinant yeast delivered functional nucleic acids to macrophages, especially when constitutively biosynthesized mRNA was used as cargo. Interestingly, expression of the protein encoded for by the delivered nucleic acid was higher in M2 cells when compared to M1 macrophages. Finally, the delivery of mRNA coding for the pro-inflammatory regulators MYD88 and TNF to M2 macrophages induced a prolonged upregulation of pro-inflammatory and cytotoxic cytokines in these cells, suggesting their successful re-education towards an anti-tumor M1 phenotype. Our results suggest the use of yeast-based gene delivery as a promising approach for the treatment of pathologic conditions that may benefit from the presence of M1-polarized macrophages, such as cancer.

Development of Cancer Vaccines Targeting Brachyury, a Transcription Factor Associated with Tumor Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is recognized as a relevant process during the progression of carcinomas towards metastatic disease. Epithelial cancer cells undergoing an EMT program may acquire mesenchymal features, motility, invasiveness, and resistance to a variety of anticancer therapeutics. Preventing or reverting the EMT process in carcinomas has the potential to minimize tumor dissemination and the emergence of therapeutic resistance. One of the strategies currently under investigation to target tumor cells undergoing EMT is the generation of a sustained immune response directed against an essential molecular driver of the process. This review focuses on the current development of immune-mediated anticancer interventions aimed at targeting a transcription factor, brachyury, associated with human tumor EMT. Also presented here is a summary of recent studies demonstrating a role for EMT in tumor resistance to immune effector cytotoxicity, and the study of novel strategies aimed at reverting the EMT to be used in combination with immune-mediated anticancer interventions.