Targeting immune effector cells to promote antibody-induced cytotoxicity in cancer immunotherapy

Organoids: new frontiers in tumor immune microenvironment research

The tumor microenvironment (TME) contains cells that regulate medication response and cancer growth in a major way. Tumor immunology research has been rejuvenated and cancer treatment has been changed by immunotherapy, a rapidly developing therapeutic approach. The growth patterns of tumor cells in vivo and the heterogeneity, complexity, and individuality of tumors produced from patients are not reflected in traditional two-dimensional tumor cell profiles. On the other hand, an in vitro three-dimensional (3D) model called the organoid model is gaining popularity. It can replicate the physiological and pathological properties of the original tissues in vivo. Tumor cells are the source of immune organoids. The TME characteristics can be preserved while preserving the variety of tumors by cultivating epithelial tumor cells with various stromal and immunological components. In addition to having genetic and physical similarities to human diseases and the ability to partially reconstruct the complex structure of tumors, these models are now widely used in research fields including cancer, developmental biology, regenerative mechanisms, drug development, disease modeling, and organ transplantation. This study reviews the function of organoids in immunotherapy and the tumor immune milieu. We also discuss current developments and suggest translational uses of tumor organoids in immuno-oncology research, immunotherapy modeling, and precision medicine.

Organoid Models for Precision Cancer Immunotherapy

Cancer immunotherapy is exploited for the treatment of disease by modulating the immune system. Since the conventional in vivo animal and 2D in vitro models insufficiently recapitulate the complex tumor immune microenvironment (TIME) of the original tumor. In addition, due to the involvement of the immune system in cancer immunotherapy, more physiomimetic cancer models, such as patient-derived organoids (PDOs), are required to evaluate the efficacy of immunotherapy agents. On the other hand, the dynamic interactions between the neoplastic cells and non-neoplastic host components in the TIME can promote carcinogenesis, tumor metastasis, cancer progression, and drug resistance of cancer cells. Indeed, tumor organoid models can properly recapitulate the TIME by preserving endogenous stromal components including various immune cells, or by adding exogenous immune cells, cancer-associated fibroblasts (CAFs), vasculature, and other components. Therefore, organoid culture platforms could model immunotherapy responses and facilitate the immunotherapy preclinical testing. Here, we discuss the various organoid culture approaches for the modeling of TIME and the applications of complex tumor organoids in testing cancer immunotherapeutics and personalized cancer immunotherapy.

Unconventional T cells and kidney disease

Unconventional T cells are a diverse and underappreciated group of relatively rare lymphocytes that are distinct from conventional CD4⁺ and CD8⁺ T cells, and that mainly recognize antigens in the absence of classical restriction through the major histocompatibility complex (MHC). These non-MHC-restricted T cells include mucosal-associated invariant T (MAIT) cells, natural killer T (NKT) cells, γδ T cells and other, often poorly defined, subsets. Depending on the physiological context, unconventional T cells may assume either protective or pathogenic roles in a range of inflammatory and autoimmune responses in the kidney. Accordingly, experimental models and clinical studies have revealed that certain unconventional T cells are potential therapeutic targets, as well as prognostic and diagnostic biomarkers. The responsiveness of human Vγ9Vδ2 T cells and MAIT cells to many microbial pathogens, for example, has implications for early diagnosis, risk stratification and targeted treatment of peritoneal dialysis-related peritonitis. The expansion of non-Vγ9Vδ2 γδ T cells during cytomegalovirus infection and their contribution to viral clearance suggest that these cells can be harnessed for immune monitoring and adoptive immunotherapy in kidney transplant recipients. In addition, populations of NKT, MAIT or γδ T cells are involved in the immunopathology of IgA nephropathy and in models of glomerulonephritis, ischaemia-reperfusion injury and kidney transplantation.

Organoid models of the tumor microenvironment and their applications

A small percentage of data obtained from animal/2D culture models can be translated to humans. Therefore, there is a need to using native tumour microenvironment mimicking models to improve preclinical screening and reduce this attrition rate. For this purpose, currently, the utilization of organoids is expanding. Tumour organoids can recapitulate tumour microenvironment that is including cancer cells and non-neoplastic host components. Indeed, tumour organoids, both phenotypically and genetically, resemble the tumour tissue that originated from it. The unique properties of the tumour microenvironment can significantly affect drug response and cancer progression. In this review, we will discuss about various organoid culture strategies for modelling the tumour immune microenvironment, their applications and advantages in cancer research such as testing cancer immunotherapeutics, developing novel approaches for personalized medicine, testing drug toxicity, drug screening, study cancer initiation and progression, and we will also review the limitations of organoid culture systems.

Development of an antibody-dependent cellular cytotoxicity reporter assay for measuring anti-Middle East Respiratory Syndrome antibody bioactivity

Middle East Respiratory Syndrome coronavirus (MERS-CoV) is a highly virulent pathogen that causes Middle East Respiratory Syndrome (MERS). Anti-MERS-CoV antibodies play an integral role in the prevention and treatment against MERS-CoV infections. Bioactivity is a key quality attribute of therapeutic antibodies, and high accuracy and precision are required. The major methods for evaluating the antiviral effect of antiviral antibodies include neutralization assays using live viruses or pseudoviruses are highly variable. Recent studies have demonstrated that the antibody-dependent cellular cytotoxicity (ADCC) activity of antiviral antibodies is more consistent with the virus clearance effect in vivo than neutralization activity. However, no reports evaluating the ADCC activity of anti-MERS antibodies have been published to date. Here, we describe the development of a robust and reliable cell-based reporter gene assay for the determination of ADCC activity of anti-MERS antibodies using 293T/MERS cells stably expressing the spike protein of MERS-CoV (MERS-S) as target cells and the engineered Jurkat/NFAT-luc/FcγRIIIa stably expressing FcγRIIIA and NFAT reporter gene as effector cells. According to the ICH-Q2 analytical method guidelines, we carefully optimized the experimental conditions and assessed the performance of our assay. In addition, we found that the ADCC activity of afucosylated anti-MERS antibodies is higher than their fucosylated counterparts. The establishment of this ADCC determination system provides a novel method for evaluating the bioactivity of anti-MERS antibodies and improving ADCC activity through modification of N-glycosylation of the Fc segment.

Organoid Models of Tumor Immunology

Cellular interactions in the tumor microenvironment (TME) significantly govern cancer progression and drug response. The efficacy of clinical immunotherapies has fostered an exponential interest in the tumor immune microenvironment, which in turn has engendered a pressing need for robust experimental systems modeling patient-specific tumor-immune interactions. Traditional 2D in vitro tumor immunotherapy models have reconstituted immortalized cancer cell lines with immune components, often from peripheral blood. However, newly developed 3D in vitro organoid culture methods now allow the routine culture of primary human tumor biopsies and increasingly incorporate immune components. Here, we present a viewpoint on recent advances, and propose translational applications of tumor organoids for immuno-oncology research, immunotherapy modeling, and precision medicine.

A Viral Nanoparticle Cancer Vaccine Delays Tumor Progression and Prolongs Survival in a HER2+ Tumor Mouse Model

Human epidermal growth factor receptor 2 (HER2) overexpression is associated with aggressive tumors with increased incidence of metastasis and recurrence. Therapeutic antibodies such as Trastuzumab inhibit tumor growth through blockade of HER2 receptors. However, the short lifespan of such therapeutic antibodies necessitates repeat administrations with ensuing cardiac toxicity and development of resistance, while offering no protection against relapse. Cancer vaccines targeting HER2 can overcome these shortcomings of passive immunotherapy by instigating an endogenous and sustained immune response and memory against the cancer antigen. The efficacy of a viral nanoparticle (VNP)-based cancer vaccine is demonstrated here in activating a potent anti-HER2 immune response that delays progression of primary tumors as well as metastases and prolongs survival in mice. The results illustrate that the VNP-based vaccine instigates HER2-specific antibodies as well as effector and memory T cells, which contributes to the effectiveness of the vaccine. Given the highly aggressive course of HER2+ cancers, inhibition of disease progression by such cancer vaccines could provide a critical window for interventions with other adjuvant therapies. Moreover, the immune memory generated by this viral nanoparticle-based cancer vaccine could mitigate relapse of the disease.

Role of altered immune cells in liver diseases: a review

Immune cells play an important role in controlling liver tumorigenesis, viral hepatitis, liver fibrosis and contribute to pathogenesis of liver inflammation and injury. Accumulating evidence suggests the effectiveness of natural killer (NK) cells and Kupffer cells (KCs) against viral hepatitis, hepatocellular damage, liver fibrosis, and carcinogenesis. Activation of natural killer cells provides a novel therapeutic strategy to cure liver related diseases. This review discusses the emerging roles of immune cells in liver disorders and it will provide baseline data to scientists to design better therapies for treatment.

Gene-modified NK-92MI cells expressing a chimeric CD16-BB-ζ or CD64-BB-ζ receptor exhibit enhanced cancer-killing ability in combination with therapeutic antibody

Natural killer (NK) cells play a pivotal role in monoclonal antibody-mediated immunotherapy through the antibody-dependent cell-mediated cytotoxicity (ADCC) mechanism. NK-92MI is an interleukin-2 (IL-2)-independent cell line, which was derived from NK-92 cells with superior cytotoxicity toward a wide range of tumor cells in vitro and in vivo. Nonetheless, the Fc-receptor (CD16) that usually mediates ADCC is absent in NK-92 and NK-92MI cells. To apply NK-92MI cell-based immunotherapy to cancer treatment, we designed and generated two chimeric receptors in NK-92MI cells that can bind the Fc portion of human immunoglobulins. The construct includes the low-affinity Fc receptor CD16 (158F) or the high-affinity Fc receptor CD64, with the addition of the CD8a extracellular domain, CD28 transmembrane domains, two costimulatory domains (CD28 and 4-1BB), and the signaling domain from CD3ζ. The resulting chimeric receptors, termed CD16-BB-ζ and CD64-BB-ζ, were used to generate modified NK-92MI cells expressing the chimeric receptor, which were named NK-92MI^hCD16 and NK-92MI^hCD64 cells, respectively. We found that NK-92MI^hCD16 and NK-92MI^hCD64 cells significantly improved cytotoxicity against CD20-positive non-Hodgkin's lymphoma cells in the presence of rituximab. These results suggest that the chimeric receptor-expressing NK-92MI cells may enhance the clinical responses to currently available anticancer monoclonal antibodies.

Safety evaluation of a human chimeric monoclonal antibody that recognizes the extracellular loop domain of claudin-2

Claudin-2 (CLDN-2), a pore-forming tight junction protein with a tetra-transmembrane domain, is involved in carcinogenesis and the metastasis of some cancers. Although CLDN-2 is highly expressed in the tight junctions of the liver and kidney, whether CLDN-2 is a safe target for cancer therapy remains unknown. We recently generated a rat monoclonal antibody (mAb, clone 1A2) that recognizes the extracellular domains of human and mouse CLDN-2. Here, we investigated the safety of CLDN-2-targeted cancer therapy by using 1A2 as a model therapeutic antibody. Because most human therapeutic mAbs are IgG1 subtype that can induce antibody-dependent cellular cytotoxicity, we generated a human-rat chimeric IgG1 form of 1A2 (xi-1A2). xi-1A2 activated Fcγ receptor IIIa in the presence of CLDN-2-expressing cells, indicating that xi-1A2 likely exerts antibody-dependent cellular cytotoxicity. At 24 h after its intravenous injection, xi-1A2 was distributed into the liver, kidney, and tumor tissues of mice bearing CLDN-2-expressing fibrosarcoma cells. Treatment of the xenografted mice with xi-1A2 attenuated tumor growth without apparent adverse effects, such as changes in body weight and biochemical markers of liver and kidney injury. These results support xi-1A2 as the lead candidate mAb for safe CLDN-2-targeted cancer therapy.

VEGFR2 targeted antibody fused with MICA stimulates NKG2D mediated immunosurveillance and exhibits potent anti-tumor activity against breast cancer

Binding of MHC class I-related chain molecules A and B (MICA/B) to the natural killer (NK) cell receptor NK group 2, member D (NKG2D) is thought critical for activating NK-mediated immunosurveillance. Angiogenesis is important for tumor growth and interfering with angiogenesis using the fully human IgG1 anti-VEGFR2 (vascular endothelial growth factor receptor 2) antibody (mAb04) can be effective in treating malignancy. In an effort to make mAb04 more effective we have generated a novel antibody fusion protein (mAb04-MICA) consisting of mAb04 and MICA. We found that mAb04-MICA maintained the anti-angiogenic and antineoplastic activities of mAb04, and also enhanced immunosurveillance activated by the NKG2D pathway. Moreover, in human breast tumor-bearing nude mice, mAb04-MICA demonstrated superior anti-tumor efficacy compared to combination therapy of mAb04 + Docetaxel or Avastin + Docetaxel, highlighting the immunostimulatory effect of MICA. In conclusion, mAb04-MICA provided new inspiration for anti-tumor treatment and had prospects for clinical application.

The humanized anti-human AMHRII mAb 3C23K exerts an anti-tumor activity against human ovarian cancer through tumor-associated macrophages

Müllerian inhibiting substance, also called anti-Müllerian hormone (AMH), inhibits proliferation and induces apoptosis of AMH type II receptor-positive tumor cells, such as human ovarian cancers (OCs). On this basis, a humanized glyco-engineered monoclonal antibody (3C23K) has been developed. The aim of this study was therefore to experimentally confirm the therapeutic potential of 3C23K in human OCs. We first determined by immunofluorescence, immunohistochemistry and cytofluorometry analyses the expression of AMHRII in patient’s tumors and found that a majority (60 to 80% depending on the detection technique) of OCs were positive for this marker. We then provided evidence that the tumor stroma of OC is enriched in tumor-associated macrophages and that these cells are responsible for 3C23K-induced killing of tumor cells through ADCP and ADCC mechanisms. In addition, we showed that 3C23K reduced macrophages induced-T cells immunosuppression. Finally, we evaluated the therapeutic efficacy of 3C23K alone and in combination with a carboplatin-paclitaxel chemotherapy in a panel of OC Patient-Derived Xenografts. In those experiments, we showed that 3C23K significantly increased the proportion and the quality of chemotherapy-based in vivo responses. Altogether, our data support the potential interest of AMHRII targeting in human ovarian cancers and the evaluation of 3C23K in further clinical trials.

Predictive value of TLR7 polymorphism for cetuximab-based chemotherapy in patients with metastatic colorectal cancer

The TLR7 and TLR9 signalings are implicated in the regulation of the immune system through type-I interferon induction. Preclinical studies have demonstrated the immunomodulatory and antitumor effects of TLR7 and TLR9 agonists in combination with cetuximab. We tested the hypothesis that genetic variations in TLR7 and TLR9 and their downstream molecules IRF5 and IRF7 were associated with outcomes in metastatic colorectal cancer (mCRC) patients receiving cetuximab-based chemotherapy. Six single nucleotide polymorphisms (SNPs) in TLR7, TLR9, IRF5 and IRF7 were tested for the association with RR, PFS, and OS in KRAS-wild type mCRC patients. Patients treated with FOLFIRI + cetuximab or FOLFIRI + bevacizumab in the FIRE-3 trial served as a discovery set (FIRE3-Cet, n = 244) or a control set (FIRE3-Bev, n = 246), respectively. Patients treated with FOLFOX or SOX + cetuximab in the JACCRO-CC05/06 trial served as a validation set (JACCRO, n = 76). Genomic DNA isolated from tumor tissue samples was analyzed by PCR-based direct sequencing. In the discovery cohort, patients with the TLR7 rs3853839 G/G variant showed a trend toward longer PFS than those with any C variants (median 10.0 vs. 11.8 months, HR 1.39, p = 0.092). This preliminary association was confirmed in the validation cohort, and those with the G/G genotype showed a PFS benefit compared with others (univariate: 9.1 vs. 11.6 months, HR 2.04, p = 0.005, multivariate: HR 2.02, 95% CI: 1.14-3.55, p = 0.015). This association was not observed in the control cohort. Our findings suggest that TLR7 rs3853839 predicts the outcome of cetuximab-based chemotherapy in mCRC patients.

Anti-CD20-interleukin-21 fusokine targets malignant B cells via direct apoptosis and NK-cell–dependent cytotoxicity

Delivering IL-21 to tumor B cells by fusion with anti-CD20 antibody (αCD20-IL-21 fusokine) is a potent antilymphoma therapeutic strategy. αCD20-IL-21 fusokine demonstrated superior antilymphoma activity compared with its individual components.

Results from an Integrated Safety Analysis of Urelumab, an Agonist Anti-CD137 Monoclonal Antibody

Purpose: Urelumab is an agonist antibody to CD137 with potential application as an immuno-oncology therapeutic. Data were analyzed to assess safety, tolerability, and pharmacodynamic activity of urelumab, including the dose selected for ongoing development in patients with advanced solid tumors and lymphoma.Experimental Design: A total of 346 patients with advanced cancers who had progressed after standard treatment received at least one dose of urelumab in one of three dose-escalation, monotherapy studies. Urelumab was administered at doses ranging from 0.1 to 15 mg/kg. Safety analyses included treatment-related and serious adverse events (AEs), as well as treatment-related AEs leading to discontinuation and death, with a focus on liver function test abnormalities and hepatic AEs.Results: Urelumab doses between 1 and 15 mg/kg given every 3 weeks resulted in a higher frequency of treatment-related AEs than 0.1 or 0.3 mg/kg every 3 weeks. Dose was the single most important factor contributing to transaminitis development, which was more frequent and severe at doses ≥1 mg/kg. At the MTD of 0.1 mg/kg every 3 weeks, urelumab was relatively well tolerated, with fatigue (16%) and nausea (13%) being the most common treatment-related AEs, and was associated with immunologic and pharmacodynamic activity demonstrated by the induction of IFN-inducible genes and cytokines.Conclusions: Integrated evaluation of urelumab safety data showed significant transaminitis was strongly associated with doses of ≥1 mg/kg. However, urelumab 0.1 mg/kg every 3 weeks was demonstrated to be safe, with pharmacodynamic activity supporting continued clinical evaluation of this dose as monotherapy and in combination with other immuno-oncology agents. Clin Cancer Res; 23(8); 1929-36. ©2016 AACR.

Efficacy and safety evaluation of claudin-4-targeted antitumor therapy using a human and mouse cross-reactive monoclonal antibody

Claudin‐4 (CLDN‐4), a tight‐junction protein, is overexpressed in various malignant tumors, including gastric, colorectal, pancreatic, and breast cancers. However, CLDN‐4 is also expressed in normal tissues, including the liver, pancreas, kidney, and small intestine. Whether CLDN‐4 is an effective and safe target for cancer therapy has been unclear owing to the lack of a binder with both CLDN‐4 specificity and cross‐reactivity to human and murine cells. In this study, we successfully generated a rat anti‐CLDN‐4 monoclonal antibody (5D12) that was specific to, and cross‐reactive with, human and mouse CLDN‐4. 5D12 recognized the second extracellular domain of human CLDN‐4 in a conformation‐dependent manner. A human–rat chimeric IgG1 of 5D12 (xi‐5D12) activated the FcγIIIa receptor, indicating the activation of antibody‐dependent cellular cytotoxicity in CLDN‐4‐expressing cells. Moreover, xi‐5D12 significantly suppressed tumor growth in mice bearing human colorectal and gastric tumors without apparent adverse effects, such as weight loss or liver and kidney damage. These results suggest that CLDN‐4 is a potent target for cancer therapy and that an anti‐CLDN‐4 antibody is a promising candidate anticancer agent.

Optimising Cancer Immunotherapy: Challenges and Opportunities

Cancer immunotherapy has moved to the forefront in the treatment of patients with cancer, providing a unique opportunity to achieve dramatic and lasting anti-tumour responses in a variety of tumour types. When it comes to patient selection and development of novel immunotherapeutic agents and combinations, so far we have merely scratched the surface of this therapeutic approach. Leading experts in the field of cancer immunotherapy gathered in Amsterdam, Netherlands, on 21st May 2016 for a Scientific Exchange to discuss the current status of immunotherapy within the field of oncology and explore the future of this evolving therapeutic strategy. Current challenges and limitations regarding the use of immunotherapy were addressed for tumour types such as melanoma, lung cancer, bladder cancer, and renal cell carcinoma (RCC). Recent advances and future directions in the areas of immunotherapy biomarkers and mechanisms of resistance were also examined. Current evidence for combination strategies with immunotherapy was highlighted, including combinations with other immunotherapies or with radiotherapy. Below is a summary of the key points discussed during this scientific exchange.

Generation and characterization of a human-mouse chimeric antibody against the extracellular domain of claudin-1 for cancer therapy using a mouse model

Claudin-1 (CLDN-1), an integral transmembrane protein, is an attractive target for drug absorption, prevention of infection, and cancer therapy. Previously, we generated mouse anti-CLDN-1 monoclonal antibodies (mAbs) and found that they enhanced epidermal absorption of a drug and prevented hepatitis C virus infection in human hepatocytes. Here, we investigated anti-tumor activity of a human-mouse chimeric IgG1, xi-3A2, from one of the anti-CLDN-1 mAbs, clone 3A2. Xi-3A2 accumulated in the tumor tissues in mice bearing with human CLDN-1-expressing tumor cells. Xi-3A2 activated Fcγ receptor IIIa-expressing reporter cells in the presence of human CLDN-1-expressing cells, suggesting xi-3A2 has a potential to exhibit antibody-dependent cellular cytotoxicity against CLDN-1 expressing tumor cells. We also constructed a mutant xi-3A2 antibody with Gly, Ser, and Ile substituted with Ala, Asp, and Arg at positions 236, 239, and 332 of the Fc domain. This mutant antibody showed greater activation of Fcγ receptor IIIa and in vivo anti-tumor activity in mice bearing human CLDN-1-expressing tumors than xi-3A2 did. These findings indicate that the G236A/S239D/I332E mutant of xi-3A2 might be a promising lead for tumor therapy.

Immunomodulatory antibodies for the treatment of lymphoma: Report on the CALYM Workshop

In November 2015, the CALYM Carnot Institute held a 2-d workshop to discuss the current and future development of immunomodulatory antibodies for the treatment of lymphoma. Highlights from the workshop are presented in this article.

Immunogenic versus tolerogenic phagocytosis during anticancer therapy: mechanisms and clinical translation

Phagocytosis of dying cells is a major homeostatic process that represents the final stage of cell death in a tissue context. Under basal conditions, in a diseased tissue (such as cancer) or after treatment with cytotoxic therapies (such as anticancer therapies), phagocytosis has a major role in avoiding toxic accumulation of cellular corpses. Recognition and phagocytosis of dying cancer cells dictate the eventual immunological consequences (i.e., tolerogenic, inflammatory or immunogenic) depending on a series of factors, including the type of 'eat me' signals. Homeostatic clearance of dying cancer cells (i.e., tolerogenic phagocytosis) tends to facilitate pro-tumorigenic processes and actively suppress antitumour immunity. Conversely, cancer cells killed by immunogenic anticancer therapies may stimulate non-homeostatic clearance by antigen-presenting cells and drive cancer antigen-directed immunity. On the other hand, (a general) inflammatory clearance of dying cancer cells could have pro-tumorigenic or antitumorigenic consequences depending on the context. Interestingly, the immunosuppressive consequences that accompany tolerogenic phagocytosis can be reversed through immune-checkpoint therapies. In the present review, we discuss the pivotal role of phagocytosis in regulating responses to anticancer therapy. We give particular attention to the role of phagocytosis following treatment with immunogenic or immune-checkpoint therapies, the clinical prognostic and predictive significance of phagocytic signals for cancer patients and the therapeutic strategies that can be employed for direct targeting of phagocytic determinants.

Deciphering CD137 (4-1BB) signaling in T-cell costimulation for translation into successful cancer immunotherapy

CD137 (4-1BB, TNF-receptor superfamily 9) is a surface glycoprotein of the TNFR family which can be induced on a variety of leukocyte subsets. On T and NK cells, CD137 is expressed following activation and, if ligated by its natural ligand (CD137L), conveys polyubiquitination-mediated signals via TNF receptor associated factor 2 that inhibit apoptosis, while enhancing proliferation and effector functions. CD137 thus behaves as a bona fide inducible costimulatory molecule. These functional properties of CD137 can be exploited in cancer immunotherapy by systemic administration of agonist monoclonal antibodies, which increase anticancer CTLs and enhance NK-cell-mediated antibody-dependent cell-mediated cytotoxicity. Reportedly, anti-CD137 mAb and adoptive T-cell therapy strongly synergize, since (i) CD137 expression can be used to select the T cells endowed with the best activities against the tumor, (ii) costimulation of the lymphocyte cultures to be used in adoptive T-cell therapy can be done with CD137 agonist antibodies or CD137L, and (iii) synergistic effects upon coadministration of T cells and antibodies are readily observed in mouse models. Furthermore, the signaling cytoplasmic tail of CD137 is a key component of anti-CD19 chimeric antigen receptors that are used to redirect T cells against leukemia and lymphoma in the clinic. Ongoing phase II clinical trials with agonist antibodies and the presence of CD137 sequence in these successful chimeric antigen receptors highlight the importance of CD137 in oncoimmunology.

A promising sword of tomorrow: Human γδ T cell strategies reconcile allo-HSCT complications

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is potentially a curative therapeutic option for hematological malignancies. In clinical practice, transplantation associated complications greatly affected the final therapeutical outcomes. Currently, primary disease relapse, graft-versus-host disease (GVHD) and infections remain the three leading causes of a high morbidity and mortality in allo-HSCT patients. Various strategies have been investigated in the past several decades including human γδ T cell-based therapeutical regimens. In different microenvironments, human γδ T cells assume features reminiscent of classical Th1, Th2, Th17, NKT and regulatory T cells, showing diverse biological functions. The cytotoxic γδ T cells could be utilized to target relapsed malignancies, and recently regulatory γδ T cells are defined as a novel implement for GVHD management. In addition, human γδ Τ cells facilitate control of post-transplantation infections and participate in tissue regeneration and wound healing processes. These features potentiate γδ T cells a versatile therapeutical agent to target transplantation associated complications. This review focuses on insights of applicable potentials of human γδ T cells reconciling complications associated with allo-HSCT. We believe an improved understanding of pertinent γδ T cell functions would be further exploited in the design of innovative immunotherapeutic approaches in allo-HSCT, to reduce mortality and morbidity, as well as improve quality of life for patients after transplantation.

Melanoma: oncogenic drivers and the immune system

Advances and in-depth understanding of the biology of melanoma over the past 30 years have contributed to a change in the consideration of melanoma as one of the most therapy-resistant malignancies. The finding that oncogenic BRAF mutations drive tumor growth in up to 50% of melanomas led to a molecular therapy revolution for unresectable and metastatic disease. Moving beyond BRAF, inactivation of immune regulatory checkpoints that limit T cell responses to melanoma has provided targets for cancer immunotherapy. In this review, we discuss the molecular biology of melanoma and we focus on the recent advances of molecularly targeted and immunotherapeutic approaches.

Tumor-targeted and immune-targeted monoclonal antibodies: Going from passive to active immunotherapy

Monoclonal antibodies (mAbs) have inaugurated the concepts of tumor-targeted therapy and personalized medicine. A new family of mAbs is currently emerging in the clinic, which target immune cells rather than cancer cells. These immune-targeted therapies have recently demonstrated long-term tumor responses in adults with refractory/relapsing metastatic solid tumors. Pediatric cancers are different from their adult counterparts in terms of histological features and immune infiltrates. However, the same immune checkpoint targets can be expressed within the microenvironment of pediatric tumors. The benefits of immune checkpoint blockade in pediatric cancers are currently under evaluation in early phase clinical trials.

Evolving synergistic combinations of targeted immunotherapies to combat cancer

Immunotherapy has now been clinically validated as an effective treatment for many cancers. There is tremendous potential for synergistic combinations of immunotherapy agents and for combining immunotherapy agents with conventional cancer treatments. Clinical trials combining blockade of cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) may serve as a paradigm to guide future approaches to immuno-oncology combination therapy. In this Review, we discuss progress in the synergistic design of immune-targeting combination therapies and highlight the challenges involved in tailoring such strategies to provide maximal benefit to patients.

Pyrosequencing for classification of human FcγRIIIA allotypes: a comparison with PCR-based techniques

BACKGROUND

Surface-specific antigens expressed by hematopoietic cells are attractive targets for antibody-mediated immunotherapy. Monoclonal antibodies (mAbs) involve various mechanisms to eliminate target cells, including antibody-dependent cellular cytotoxicity (ADCC)- and phagocytosis (ADCP)-mediated killing through natural killer (NK) and macrophage effector cells bearing FcγRIIIA (CD16). The clinical efficacy of ADCC is particularly impacted by a single nucleotide polymorphism (SNP) found in the gene encoding FcγRIIIA (FCGR3A), which generates a variable distribution of the 158 V/V, F/V or F/F CD16 allotypes (F = phenylalanine, V = valine) in the normal human population. Currently, most patients are not screened for CD16 allotypes, creating the potential to include in their treatment a mAb-based therapy that may have limited benefit. Therefore, it is important to identify CD16 allotypes when considering mAb therapies that require ADCC/ADCP.

OBJECTIVE

The objective of this study was to develop a reliable PCR-based assay for classification of human FcγRIIIA allotypes.

METHODS

We studied 42 normal human subjects for the incidence of FcγRIIIA-158 polymorphisms using comparative molecular approaches.

RESULTS

The results of our study showed 100% accuracy in genotyping by pyrosequencing. In contrast, nested PCR-based allele-specific restriction assay and quantitative PCR techniques proved to be relatively less sensitive and less specific in distinguishing variant genotypes.

CONCLUSION

Since the efficacy of the mAb-based targeted immunotherapy may be highly dependent upon the CD16 polymorphism in a given individual, we recommend pyrosequencing for CD16 allotype testing.

Are we nearing an era of chemotherapy-free management of indolent lymphoma?

Indolent B-cell lymphomas are heterogeneous, comprising three grades of follicular lymphoma, small lymphocytic lymphoma, Waldenstöm macroglobulinemia, marginal zone lymphoma, and most recently, possibly low proliferative mantle cell lymphoma. These lymphomas are characterized by a high responsiveness to chemotherapy or immunochemotherapy; however, in most cases, conventional therapy might not offer a cure. Furthermore, the patient's age at diagnosis, at time to first or subsequent relapses, as well as potential comorbidities often preclude the use of chemotherapy. Recent progress has been made in our understanding of dysregulated pathways and immunologic antitumor responses in indolent lymphoma. Major therapeutic advances have been achieved in the development of nonchemotherapeutic agents, making "chemo-free" treatment a near-future reality. In this article, we highlight these promising approaches, such as the combination of anti-CD20 antibodies with immunomodulatory drugs, with mAbs directed against other surface antigens such as CD22, with immunomodulatory antibodies such as PD-1, or with inhibitors of key steps in the B-cell receptor pathway signaling. However, the cost of such therapies and potential, albeit manageable, toxicity should be considered. Phase III trials will confirm the benefit of these new treatment strategies that do not require a chemotherapeutic drug and help us identify their exact place in the therapeutic armamentarium for indolent lymphoma. Here we focus on follicular lymphoma, which is the most frequent subtype of indolent lymphoma and for which an increasing body of evidence has emerged that supports the dawn of a new era of chemotherapy-free treatment. See all articles in this CCR Focus section, "Paradigm Shifts in Lymphoma."

"Velcro" engineering of high affinity CD47 ectodomain as signal regulatory protein α (SIRPα) antagonists that enhance antibody-dependent cellular phagocytosis

CD47 is a cell surface protein that transmits an anti-phagocytic signal, known as the "don't-eat-me" signal, to macrophages upon engaging its receptor signal regulatory protein α (SIRPα). Molecules that antagonize the CD47-SIRPα interaction by binding to CD47, such as anti-CD47 antibodies and the engineered SIRPα variant CV1, have been shown to facilitate macrophage-mediated anti-tumor responses. However, these strategies targeting CD47 are handicapped by large antigen sinks in vivo and indiscriminate cell binding due to ubiquitous expression of CD47. These factors reduce bioavailability and increase the risk of toxicity. Here, we present an alternative strategy to antagonize the CD47-SIRPα pathway by engineering high affinity CD47 variants that target SIRPα, which has restricted tissue expression. CD47 proved to be refractive to conventional affinity maturation techniques targeting its binding interface with SIRPα. Therefore, we developed a novel engineering approach, whereby we augmented the existing contact interface via N-terminal peptide extension, coined "Velcro" engineering. The high affinity variant (Velcro-CD47) bound to the two most prominent human SIRPα alleles with greatly increased affinity relative to wild-type CD47 and potently antagonized CD47 binding to SIRPα on human macrophages. Velcro-CD47 synergizes with tumor-specific monoclonal antibodies to enhance macrophage phagocytosis of tumor cells in vitro, with similar potency as CV1. Finally, Velcro-CD47 interacts specifically with a subset of myeloid-derived cells in human blood, whereas CV1 binds all myeloid, lymphoid, and erythroid populations interrogated. This is consistent with the restricted expression of SIRPα compared with CD47. Herein, we have demonstrated that "Velcro" engineering is a powerful protein-engineering tool with potential applications to other systems and that Velcro-CD47 could be an alternative adjuvant to CD47-targeting agents for cancer immunotherapy.

NK cell-based immunotherapies in Pediatric Oncology

The past decade has seen several anticancer immunotherapeutic strategies transition from "promising preclinical models" to treatments with proven clinical activity or benefit. In 2013, the journal Science selected the field of Cancer Immunotherapy as the overall number-1 breakthrough for the year in all of scientific research. In the setting of cancer immunotherapy for adult malignancies, many of these immunotherapy strategies have relied on the cancer patient's endogenous antitumor T-cell response. Although much promising research in pediatric oncology is similarly focused on T-cell reactivity, several pediatric malignancies themselves, or the chemo-radiotherapy used to achieve initial responses, can be associated with profound immune suppression, particularly of the T-cell system. A separate component of the immune system, also able to mediate antitumor effects and less suppressed by conventional cancer treatment, is the NK-cell system. In recent years, several distinct immunotherapeutic approaches that rely on the activity of NK cells have moved from preclinical development into clinical testing, and some have shown clear antitumor benefit. This review provides an overview of NK cell-based immunotherapy efforts that are directed toward childhood malignancies, with an emphasis on protocols that are already in clinical testing.

DNA damage response and evasion from immunosurveillance in CLL: new options for NK cell-based immunotherapies

Chronic lymphocytic leukemia (CLL) is the most prominent B cell malignancy among adults in the Western world and characterized by a clonal expansion of B cells. The patients suffer from severe immune defects resulting in increased susceptibility to infections and failure to generate an antitumor immune response. Defects in both, DNA damage response (DDR) pathway and crosstalk with the tissue microenvironment have been reported to play a crucial role for the survival of CLL cells, therapy resistance and impaired immune response. To this end, major advances over the past years have highlighted several T cell immune evasion mechanisms in CLL. Here, we discuss the consequences of an impaired DDR pathway for detection and elimination of CLL cells by natural killer (NK) cells. NK cells are considered to be a major component of the immunosurveillance in leukemia but NK cell activity is impaired in CLL. Restoration of NK cell activity using immunoligands and immunoconstructs in combination with the conventional chemotherapy may provide a future perspective for CLL treatment.

Discovery of anti-claudin-1 antibodies as candidate therapeutics against hepatitis C virus

Claudin-1 (CLDN1), a known host factor for hepatitis C virus (HCV) entry and cell-to-cell transmission, is a target molecule for inhibiting HCV infection. We previously developed four clones of mouse anti-CLDN1 monoclonal antibody (mAb) that prevented HCV infection in vitro. Two of these mAbs showed the highest antiviral activity. Here, we optimized the anti-CLDN1 mAbs as candidates for therapeutics by protein engineering. Although Fab fragments of the mAbs prevented in vitro HCV infection, their inhibitory effects were much weaker than those of the whole mAbs. In contrast, human chimeric IgG1 mAbs generated by grafting the variable domains of the mouse mAb light and heavy chains inhibited in vitro HCV infection as efficiently as the parental mouse mAbs. However, the chimeric IgG1 mAbs activated Fcγ receptor, suggesting that cytotoxicity against mAb-bound CLDN1-expressing cells occurred through the induction of antibody-dependent cellular cytotoxicity (ADCC). To avoid ADCC-induced side effects, we prepared human chimeric IgG4 mAbs. The chimeric IgG4 mAbs did not activate Fcγ receptor or induce ADCC, but they prevented in vitro HCV infection as efficiently as did the parental mouse mAbs. These findings indicate that the IgG4 form of human chimeric anti-CLDN1 mAb may be a candidate molecule for clinically applicable HCV therapy.

Development of an anti-claudin-3 and -4 bispecific monoclonal antibody for cancer diagnosis and therapy

Most malignant tumors are derived from epithelium, and claudin (CLDN)-3 and CLDN-4 are frequently overexpressed in such tumors. Although antibodies have potential in cancer diagnostics and therapy, development of antibodies against CLDNs has been difficult because the extracellular domains of CLDNs are too small and there is high homology among human, rat, and mouse sequences. Here, we created a monoclonal antibody that recognizes human CLDN-3 and CLDN-4 by immunizing rats with a plasmid vector encoding human CLDN-4. A hybridoma clone that produced a rat monoclonal antibody recognizing both CLDN-3 and -4 (clone 5A5) was obtained from a hybridoma screen by using CLDN-3- and -4-expressing cells; 5A5 did not bind to CLDN-1-, -2-, -5-, -6-, -7-, or -9-expressing cells. Fluorescence-conjugated 5A5 injected into xenograft mice bearing human cancer MKN74 or LoVo cells could visualize the tumor cells. The human-rat chimeric IgG1 monoclonal antibody (xi5A5) activated FcγRIIIa in the presence of CLDN-3- or -4-expressing cells, indicating that xi5A5 may exert antibody-dependent cellular cytotoxicity. Administration of xi5A5 attenuated tumor growth in xenograft mice bearing MKN74 or LoVo cells. These results suggest that 5A5 shows promise in the development of a diagnostic and therapeutic antibody for cancers.

Role of Fc-mediated antibody function in protective immunity against HIV-1

The importance of Fc-mediated effector function in protective immunity to HIV-1 (hereafter referred to simply as HIV) is becoming increasingly apparent. A large of number of studies in natural infection cohorts, spanning the last 26 years, have associated Fc-mediated effector function, particularly antibody-dependent cellular cytotoxicity, with a favourable clinical course. These studies strongly suggest a role for Fc-mediated effector function in the post-infection control of viraemia. More recently, studies in both humans and non-human primates (NHPs) also implicate Fc-mediated effector function in blocking HIV acquisition. Accordingly, this review will discuss the results supporting a role of Fc-mediated effector function in both blocking acquisition and post-infection control of viraemia. Parallel studies in NHPs and humans will be compared for common themes. Context for this discussion will be provided by summarizing the temporal emergence of key host and virological events over the course of an untreated HIV infection framing where, when and how Fc-mediated effector function might be protective. A hypothesis that Fc-mediated effector function protects primarily in the early stages of both acquisition and post-infection control of viraemia will be developed.

Physiological organization of immune response based on the homeostatic mechanism of matrix reprogramming: implication in tumor and biotechnology

It is accepted that the immune system responds to pathogens with activation of antigen-independent innate and antigen-dependent adaptive immunity. However many immune events do not fit or are even inconsistent with this notion. We developed a new homeostatic model of the immune response. This model consists of four units: a sensor, a regulator, an effector and a rehabilitator. The sensor, macrophages or lymphocytes, recognize pathogenic cells and generate alarm signals. The regulator, antigen-presenting cells, Тregs and myeloid-derived suppressor cells, evaluate the signals and together with sensor cells program the effector. The effector, programmed macrophages and lymphocytes, eliminate the pathogenic cells. The rehabilitator, M2 macrophages, restrict inflammation, provide angiogenesis and reparation of tissue damage, and restore the homeostasis. We suggest the terms "immune matrix" for a biological template of immune responses to pathogens and "matrix reprogramming" for the interdependent reprogramming of different cells in the matrix. In an adequate immune response, the matrix forms a negative feedback mechanism to support the homeostasis. We defined the cellular and phenotypic composition of a tumor immune matrix. A tumor reprograms the homeostatic negative feedback mechanism of matrix into a pathogenic positive feedback mechanism. M2 macrophages play a key role in this transformation. Therefore, macrophages are an attractive target for biotechnology. Based on our hypotheses, we are developing a cell biotechnology method for creation of macrophages with a stable antitumor phenotype. We have shown that such macrophages almost doubled the survival time of mice with tumor.

Gene-modified human α/β-T cells expressing a chimeric CD16-CD3ζ receptor as adoptively transferable effector cells for anticancer monoclonal antibody therapy

The central tumoricidal activity of anticancer monoclonal antibodies (mAb) is exerted by FcγR IIIa (CD16)-expressing effector cells in vivo via antibody-dependent cell-mediated cytotoxicity (ADCC), as observed for natural killer (NK) cells. In practice, chemotherapy-induced leukopenia and exhaustion of NK cells resulting from ADCC often hamper the clinical efficacy of cancer treatment. To circumvent this drawback, we examined in vivo the feasibility of T cells, gene-modified to express a newly generated affinity-matured (158V/V) chimeric CD16-CD3ζ receptor (cCD16ζ-T cells), as a transferable alternative effector for cancer mAb therapy. cCD16ζ-T cells were readily expandable in ex vivo culture using anti-CD2/CD3/CD28 beads and recombinant human interleukin-2 (rhIL-2), and they successfully displayed ADCC-mediated tumoricidal activity in vitro. During ADCC, ligation of opsonized cancer cells to the introduced cCD16ζ-T cells stimulated the effector cells to produce proinflammatory cytokines and release toxic granules through the activation of the Nuclear factor of activated T cells (NFAT) pathway after phosphorylation of the CD3ζ chain. In parallel, these stimulated cCD16ζ-T cells transiently proliferated and differentiated into effector memory T cells. In contrast, NK cells activated by rhIL-2 displayed similar ADCC activity, but failed to proliferate. Human cCD16ζ-T cells infused concomitantly with anti-CD20 mAb synergistically inhibited the growth of disseminated Raji cells, a CD20(+) lymphoma cell line, in immunodeficient mice, whereas similarly infused rhIL-2-treated NK cells survived for a shorter time and displayed less effective tumor suppression. Our findings strongly suggest the clinical feasibility of cCD16ζ-T cells as adoptively transferable ADCC effector cells that could potentially enhance the clinical responses mediated by currently available anticancer mAbs.

Natural ligands and antibody-based fusion proteins: harnessing the immune system against cancer

The insight that the immune system is able to eradicate tumor cells inspired the development of targeted immunotherapies. These novel approaches aim to trigger immune molecules and receptors, including CD3 on T cells and NKG2D and NKp30 on natural killer (NK) cells, to harness the immune system against cancer. In cancer patients, overcoming immune suppression induced by malignant cells or by the tumor microenvironment remains the major challenge to the clinical efficacy of immunotherapies. Recombinant constructs have been developed in various formats either utilizing natural ligands (immunoligands) or antibody-derived components (immunoconstructs) to circumvent mechanisms that counteract an effective antitumor immune response.

The yin and the yang of follicular lymphoma cell niches: role of microenvironment heterogeneity and plasticity

Follicular lymphoma (FL) results from the malignant transformation of germinal center B cells and is characterized by recurrent genetic alterations providing a direct growth advantage or facilitating interaction with tumor microenvironment. In agreement, accumulating evidences suggest a dynamic bidirectional crosstalk between FL B cells and surrounding non-malignant cells within specialized tumor niches in both invaded lymph nodes and bone marrow. Infiltrating stromal cells, macrophages, and T/NK cell subsets either contribute to anti-tumor immune response, or conversely form a tumor supportive network promoting FL B cell survival, growth, and drug resistance. This review depicts the phenotypic heterogeneity and functional plasticity of the most important FL cell partners and describes their complex interplay. We also unravel how malignant B cells recruit and subvert accessory immune and stromal cells to trigger their polarization toward a supportive phenotype. Based on these observations, innovative therapeutic approaches have been recently proposed, in order to benefit from local anti-tumor immunity and/or to selectively target the protective cell niche.

Successful radioimmunotherapy of established syngeneic rat colon carcinoma with 211At-mAb

Background

Most carcinomas are prone to metastasize despite successful treatment of the primary tumor. One way to address this clinical challenge may be targeted therapy with α-emitting radionuclides such as astatine-211 (²¹¹At). Radioimmunotherapy utilizing α-particle emitting radionuclides is considered especially suitable for the treatment of small cell clusters and single cells, although lesions of different sizes may also be present in the patient. The aim of this study was primarily to evaluate the toxicity and secondarily in vivo efficacy of a ²¹¹At-labeled monoclonal antibody (mAb) directed against colon carcinoma with tumor diameters of approximately 10 mm.

Methods

Eighteen rats with subperitoneal syngeneic colon carcinoma were allocated to three groups of six animals together with three healthy rats in each group. The groups were injected intravenously with either 150 μg of unlabeled mAbs (controls) or 2.5 or 5 MBq ²¹¹At-mAbs directed towards the Lewis Y antigen expressed on the cell membrane of several carcinomas. Tumor volume, body weight, and blood cell counts were monitored for 100 days after treatment.

Results

Local tumors were non-palpable in five out of six rats after treatment with both activities of ²¹¹At-mAbs, compared to one out of six in the control group. At the study end, half of the animals in each group given ²¹¹At-BR96 and one animal in the control group were free from disease. Radioimmunotherapy resulted in dose-dependent, transient weight loss and myelotoxicity. Survival was significantly better in the groups receiving targeted alpha therapy than in those receiving unlabeled mAbs.

Conclusions

This study demonstrates the possibility of treating small, solid colon carcinoma tumors with α-emitting radionuclides such as ²¹¹At bound to mAbs, with tolerable toxicity.

Natural killer cells in liver disease

Natural killer (NK) cells are enriched in lymphocytes within the liver and have unique phenotypic features and functional properties, including tumor necrosis factor-related apoptosis-inducing ligand-dependent cytotoxicity and specific cytokine profiles. As a key component of innate immunity in the liver, NK cells perform critical roles in host defense against pathogens and tumors through their natural cytotoxicity and cytokine production, and they also act as regulatory cells by engaging in reciprocal interactions with other types of liver cells through cell-to-cell contact and the production of cytokines. Accumulating evidence from the last decade suggests that NK cells play an important role in controlling viral hepatitis, liver fibrosis, and liver tumorigenesis, but also contribute to the pathogenesis of liver injury and inflammation. The characterization of intrahepatic NK cell functions has not only helped us to better understand the pathogenesis of liver disease, but has also revealed new therapeutic targets for managing this disease.

Recombinant human IgG antibodies recognizing distinct extracellular domains of EGF receptor exhibit different degrees of growth inhibitory effects on human A431 cancer cells

Recently, we isolated 4 distinct kinds of single chain antibody against human EGF receptor (EGFR) after screening the Keio phage display scFv library by using two methods of target-guided proximity labeling. In the current study, these monovalent scFv antibodies were converted to bivalent IgGs of humanized forms (hIgGs) by recombinant technology using the specially designed expression vectors followed by protein production in CHO cells. The resulting recombinant hIgGs were examined for their binding specificity using several different transformed human BJ cell lines that express deletion mutants of EGFR, each lacking one of 4 distinct extracellular domains (L1, L2, C1 and C2). Immuno-fluorescent microscopy and immuno-precipitation assay on these cells indicated that 4 distinct kinds of hIgGs bind to one of 3 different domains (L1, C1 and C2). Then, these hIgGs were further examined for biological effects on human A431 cancer cells, which overexpress EGFR. The results indicated that hIgG38 binding to L1 and hIgG45 binding to C2 substantially suppressed the EGF-induced phosphorylation of EGFR, resulting in the growth inhibition of A431 cancer cells. On the contrary, hIgG40 binding to C1 and hIgG42 binding to another site (epitope) of C2 exhibited no such inhibitory effects. Thus, the newly produced four recombinant hIgG antibodies recognize 4 different sites (epitopes) in 3 different extracellular domains of EGFR and exhibit different biological effects on cancer cells. These characteristics are somewhat different from the currently utilized therapeutic anti-EGFR antibodies. Hence, these hIgG antibodies will be invaluable as a research tool for the detailed molecular analysis of the EGFR-mediated signal transduction mechanism and more importantly a possible application as new therapeutic agents to treat certain types of cancers.

At diagnosis, diffuse large B-cell lymphoma patients show impaired rituximab-mediated NK-cell cytotoxicity

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin's lymphoma in adults. It is generally treated by a combination of chemotherapy and CD20-specific mAbs, such as rituximab, which act, at least partially, by activating antibody-dependent cell-mediated cytotoxicity (ADCC). ADCC involves NK cells, particularly the CD56(dim) NK-cell subset expressing CD16, the low affinity Fcγ receptor. Here, we show that CD16 expression levels are decreased in a cohort of 36 newly diagnosed DLBCL patients compared with those in 20 healthy controls (HCs). CD137, a co-stimulatory molecule expressed on activated NK cells, was also expressed at lower levels in patients compared with controls. Cells sampled from our cohort also showed severely reduced degranulation activity when challenged with rituximab-coated tumor cells, which could not be corrected by stimulation with high doses of IL-2. These results suggest that rituximab-induced NK-cell ADCC could be defective in some DLBCL patients at diagnosis. These patients should be closely monitored and attempts made to improve their NK-cell function.

Prospective of colon cancer treatments and scope for combinatorial approach to enhanced cancer cell apoptosis

Colorectal cancer is the leading cause of cancer-related mortality in the western world. It is also the third most common cancer diagnosed in both men and women in the United States with a recent estimate for new cases of colorectal cancer in the year 2012 being around 103,170. Various risk factors for colorectal cancer include life-style, diet, age, personal and family history, and racial and ethnic background. While a few cancers are certainly preventable but this does not hold true for colon cancer as it is often detected in its advanced stage and generally not diagnosed until symptoms become apparent. Despite the fact that several options are available for treating this cancer through surgery, chemotherapy, radiation therapy, immunotherapy, and nutritional-supplement therapy, but the success rates are not very encouraging when used alone where secondary complications appear in almost all these therapies. To maximize the therapeutic-effects in patients, combinatorial approaches are essential. In this review we have discussed the therapies previously and currently available to patients diagnosed with colorectal-cancer, focus on some recent developments in basic research that has shaded lights on new therapeutic-concepts utilizing macrophages/dendritic cells, natural killer cells, gene delivery, siRNA-, and microRNA-technology, and specific-targeting of tyrosine kinases that are either mutated or over-expressed in the cancerous cell to treat these cancer. Potential strategies are discussed where these concepts could be applied to the existing therapies under a comprehensive approach to enhance the therapeutic effects.