Cellular immunotherapy for patients with metastatic colorectal carcinoma using lymph node lymphocytes localized in vivo by radiolabeled monoclonal antibody

Technical Considerations for the Generation of Adoptively Transferred T Cells in Cancer Immunotherapy

A significant function of the immune system is the surveillance and elimination of aberrant cells that give rise to cancer. Even when tumors are well established and metastatic, immune-mediated spontaneous regressions have been documented. While there are have been various forms of immunotherapy, one of the most widely studied for almost 40 years is adoptive cellular immunotherapy, but its success has yet to be fully realized. Adoptive cell transfer (ACT) is a therapeutic modality that has intrigued physicians and researchers for its many theoretical benefits. Preclinical investigations and human trials have utilized natural killer (NK) cells, dendritic cells (DC), macrophages, T-cells or B-cells for ACT with the most intense research focused on T-cell ACT. T-cells are exquisitely specific to the target of its T-cell receptor (TCR), thus potentially reducing the amount of collateral damage and off-target effects from treatment. T-cells also possess a memory subset that may reduce the risk of recurrence of a cancer after the successful treatment of the primary disease. There are several options for the source of T-cells used in the generation of cells for ACT. Perhaps the most widely known source is T-cells generated from tumor-infiltrating lymphocytes (TILs). However, studies have also employed peripheral blood mononuclear cells (PBMCs), lymph nodes, and even induced pluripotent stem cells (IPSCs) as a source of T-cells. Several important technical considerations exist regarding benefits and limitations of each source of T-cells. Unique aspects of T-cells factor into their ability to be efficacious in ACT including the total number of cells available for ACT, the anti-tumor efficacy on a per cell basis, the repertoire of TCRs specific to tumor cells, and their ability to traffic to various organs that harbor tumor. Current research is attempting to unlock the full potential of these cells to effectively and safely treat cancer.

Phase I/II study of adjuvant immunotherapy with sentinel lymph node T lymphocytes in patients with colorectal cancer

Although the development of multi-disciplinary management has improved the survival of colorectal cancer (CRC), the prognosis of metastatic CRC patients remains poor. Accumulating evidence has demonstrated that immunotherapy with cancer vaccines and adoptive T cell transfusions may improve outcomes as an adjuvant to current standard CRC treatment. In this phase I/II study, 71 CRC patients who underwent radical surgery (stage I-III, n = 46) or palliative surgery (stage IV with non-resectable synchronous metastases, n = 25) were included. In the first part of this study, sentinel lymph nodes (SLNs) were intraoperatively identified in 55 patients (46 with stage I-III CRC and 9 with stage IV CRC). SLN-T lymphocytes were expanded ex vivo for a median of 28.5 days (range 23-33 days). Thereafter, a median of 153 × 10(6) cells (range 20.7-639.0 × 10(6)) were transfused. No treatment-related toxicity was observed. In the second part of this study, the stage IV patients were routinely followed. The 24-month survival rate of the SLN-T lymphocyte group was significantly higher than that of the control group: 55.6 versus 17.5% (p = 0.02). The median overall survival of the SLN-T lymphocyte and control groups was 28 and 14 months, respectively. Our study showed that adjuvant SLN-T lymphocyte immunotherapy is feasible and safe for postoperative CRC patients. Additionally, this therapy may improve the long-term survival of metastatic CRC. Further investigation of the clinical efficacy and anti-tumor immunity is warranted.

In vivo imaging of therapy-induced anti-cancer immune responses in humans

Immunotherapy aims to re-engage and revitalize the immune system in the fight against cancer. Research over the past decades has shown that the relationship between the immune system and human cancer is complex, highly dynamic, and variable between individuals. Considering the complexity, enormous effort and costs involved in optimizing immunotherapeutic approaches, clinically applicable tools to monitor therapy-induced immune responses in vivo are most warranted. However, the development of such tools is complicated by the fact that a developing immune response encompasses several body compartments, e.g., peripheral tissues, lymph nodes, lymphatic and vascular systems, as well as the tumor site itself. Moreover, the cells that comprise the immune system are not static but constantly circulate through the vascular and lymphatic system. Molecular imaging is considered the favorite candidate to fulfill this task. The progress in imaging technologies and modalities has provided a versatile toolbox to address these issues. This review focuses on the detection of therapy-induced anticancer immune responses in vivo and provides a comprehensive overview of clinically available imaging techniques as well as perspectives on future developments. In the discussion, we will focus on issues that specifically relate to imaging of the immune system and we will discuss the strengths and limitations of the current clinical imaging techniques. The last section provides future directions that we envision to be crucial for further development.

Imaging of cellular therapies

Cellular therapy promises to revolutionize medicine, by restoring tissue and organ function, and combating key disorders including cancer. As with all major developments, new tools must be introduced to allow optimization. For cell therapy, the key tool is in vivo imaging for real time assessment of parameters such as cell localization, numbers and viability. Such data is critical to modulate and tailor the therapy for each patient. In this review, we discuss recent work in the field of imaging cell therapies in the clinic, including preclinical work where clinical examples are not yet available. Clinical trials in which transferred cells were imaged using magnetic resonance imaging (MRI), nuclear scintigraphy, single photon emission computed tomography (SPECT), and positron emission tomography (PET) are evaluated from an imaging perspective. Preclinical cell tracking studies that focus on fluorescence and bioluminescence imaging are excluded, as these modalities are generally not applicable to clinical cell tracking. In this review, we assess the advantages and drawbacks of the various imaging techniques available, focusing on immune cells, particularly dendritic cells. Both strategies of prelabeling cells before transplant and the use of an injectable label to target cells in situ are covered. Finally, we discuss future developments, including the emergence of multimodal imaging technology for cell tracking from the preclinical to the clinical realm.

Sentinel node lymphocytes: tumour reactive lymphocytes identified intraoperatively for the use in immunotherapy of colon cancer

The sentinel node is the first lymph node to receive lymphatic drainage from a tumour and is usually the first site of metastases. Today, the sentinel node is used for tumour staging. Here, we focus on its immunological role and investigate lymphocytic function in sentinel nodes, identified intraoperatively by peritumoural dye injection, from 15 patients with colon cancer. Tumour infiltrating lymphocytes, sentinel and nonsentinel lymph node cells and peripheral blood leukocytes were studied by flow cytometry, proliferation assays and interferon-γ secretion after activation with autologous tumour homogenate. Whereas tumour-infiltrating lymphocytes were nonresponsive in the proliferation assays, lymphocytes from sentinel nodes proliferated dose dependently and secreted interferon-γ upon stimulation with tumour homogenate. The responses were of varying magnitude and tended to be weaker in metastatic sentinel nodes. Sentinel node lymphocytes represents an enriched source of tumour reactive lymphocytes, and may be useful in future trials of adoptive immunotherapy.

Recent developments in the systemic therapy of advanced gastroesophageal malignancies

Cancers of the upper gastrointestinal tract are a common cause of worldwide morbidity and mortality. The prognosis for patients with these cancers remains poor and only a minority of patients are cured. Systemic therapy has been used to treat patients with advanced disease but outcomes have not improved dramatically in the past few decades. Newer, more effective agents are desperately needed, and agents such as the taxanes (docetaxel and paclitaxel), irinotecan, oxaliplatin and capecitabine have recently shown some promise. In addition, molecularly targeted, non-cytotoxic therapies are being evaluated with the hope of improving the available therapeutic options. This article reviews the current clinical data regarding systemic therapy for patients with advanced upper gastrointestinal malignancies.

Role of NKG2D signaling in the cytotoxicity of activated and expanded CD8+ T cells

Activating and expanding T cells using T-cell receptor (TCR) cross-linking antibodies and interleukin 2 (IL-2) results in potent cytotoxic effector cells capable of recognizing a broad range of malignant cell targets, including autologous leukemic cells. The mechanism of target cell recognition has previously been unknown. Recent studies show that ligation of NKG2D on natural killer (NK) cells directly induces cytotoxicity, whereas on T cells it costimulates TCR signaling. Here we demonstrate that NKG2D expression is up-regulated upon activation and expansion of human CD8+ T cells. Antibody blocking, redirected cytolysis, and small interfering RNA (siRNA) studies using purified CD8+ T cells demonstrate that cytotoxicity against malignant target cells occurs through NKG2D-mediated recognition and signaling and not through the TCR. Activated and expanded CD8+ T cells develop cytotoxicity after 10 to 14 days of culture, coincident with the expression of the adapter protein DAP10. T cells activated and expanded in low (30 U/mL) and high (300 U/mL) concentrations of IL-2 both up-regulated NKG2D expression equally, but only cells cultured in high-dose IL-2 expressed DAP10 and were cytotoxic. Collectively these results establish that NKG2D triggering accounts for the majority of major histocompatibility complex (MHC)-unrestricted cytotoxicity of activated and expanded CD8+ T cells, likely through DAP10-mediated signaling.

Adoptive-cell-transfer therapy for the treatment of patients with cancer

Adoptive immunotherapy--the isolation of antigen-specific cells, their ex vivo expansion and activation, and subsequent autologous administration--is a promising approach to inducing antitumour immune responses. The molecular identification of tumour antigens and the ability to monitor the persistence and transport of transferred cells has provided new insights into the mechanisms of tumour immunotherapy. Recent studies have shown the effectiveness of cell-transfer therapies for the treatment of patients with selected metastatic cancers. These studies provide a blueprint for the wider application of adoptive-cell-transfer therapy, and emphasize the requirement for in vivo persistence of the cells for therapeutic efficacy.

Immunotherapy for colorectal cancer

There have been significant improvements in the diagnosis and treatment of colorectal cancer over the past 15 years. However, some 30% of patients with colorectal cancer have disseminated disease at presentation, and furthermore, 50% of patients initially believed to be cured by surgery subsequently relapse and die of the disease. Novel treatment concepts based on understanding the molecular signatures that separate tumor from normal epithelium, such as immunotherapy, are aimed at abolishing microscopic residual disease post standard treatment. The authors provide an overview of progress in the development of specific and nonspecific immunotherapies and explain why definition of end-points and early translation of immunotherapy into the adjuvant field are key to effective use of such agents in the clinical setting.

Immunologic monitoring of cancer vaccine therapy: results of a workshop sponsored by the Society for Biological Therapy

The Society for Biological Therapy held a Workshop last fall devoted to immune monitoring for cancer immunotherapy trials. Participants included members of the academic and pharmaceutical communities as well as the National Cancer Institute and the Food and Drug Administration. Discussion focused on the relative merits and appropriate use of various immune monitoring tools. Six breakout groups dealt with assays of T-cell function, serologic and proliferation assays to assess B cell and T helper cell activity, and enzyme-linked immunospot assay, tetramer, cytokine flow cytometry, and reverse transcription polymerase chain reaction assays of T-cell immunity. General conclusions included: (1) future vaccine studies should be designed to determine whether T-cell dysfunction (tumor-specific and nonspecific) correlated with clinical outcome; (2) tetramer-based assays yield quantitative but not functional data (3) enzyme-linked immunospot assays have the lowest limit of detection (4) cytokine flow cytometry have a higher limit of detection than enzyme-linked immunospot assay, but offer the advantages of speed and the ability to identify subsets of reactive cells; (5) antibody tests are simple and accurate and should be incorporated to a greater extent in monitoring plans; (6) proliferation assays are imprecise and should not be emphasized in future studies; (7) the reverse transcription polymerase chain reaction assay is a promising research approach that is not ready for widespread application; and (8)there is a critical need to validate these assays as surrogates for vaccine potency and clinical effect. Current data and opinion support the use of a functional assay like the enzyme-linked immunospot assay or cytokine flow cytometry in combination with a quantitative assay like tetramers for immune monitoring. At present, assays appear to be most useful as measures of vaccine potency. Careful immune monitoring in association with larger scale clinical trials ultimately may enable the correlation of monitoring results with clinical benefit.

Immunotherapy for colorectal cancer: a challenge to clinical trial design

Colorectal cancer is a leading cause of morbidity and mortality with about 18 000 deaths in the UK and 56 000 in the USA each year. Despite improvements in surgical technique, radiotherapy, and adjuvant chemotherapy, 50% of patients apparently 'cured' by surgery subsequently relapse and die of the disease. There is an obvious need to develop novel rational therapies based on understanding the molecular signatures that separate tumour from normal colorectal epithelium.