Cytokine-Induced Killer Cells As Pharmacological Tools for Cancer Immunotherapy

Mesenchymal Stem/Stromal Cells as a Vehicle for Cytokine Delivery: An Emerging Approach for Tumor Immunotherapy

Pro-inflammatory cytokines can effectively be used for tumor immunotherapy, affecting every step of the tumor immunity cycle. Thereby, they can restore antigen priming, improve the effector immune cell frequencies in the tumor microenvironment (TME), and eventually strengthen their cytolytic function. A renewed interest in the anticancer competencies of cytokines has resulted in a substantial promotion in the number of trials to address the safety and efficacy of cytokine-based therapeutic options. However, low response rate along with the high toxicity associated with high-dose cytokine for reaching desired therapeutic outcomes negatively affect their clinical utility. Recently, mesenchymal stem/stromal cells (MSCs) due to their pronounced tropism to tumors and also lower immunogenicity have become a promising vehicle for cytokine delivery for human malignancies. MSC-based delivery of the cytokine can lead to the more effective immune cell-induced antitumor response and provide sustained release of target cytokines, as widely evidenced in a myriad of xenograft models. In the current review, we offer a summary of the novel trends in cytokine immunotherapy using MSCs as a potent and encouraging carrier for antitumor cytokines, focusing on the last two decades' animal reports.

Insights into an Immunotherapeutic Approach to Combat Multidrug Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has emerged as one of the most lethal cancers worldwide because of its high refractoriness and multi-drug resistance to existing chemotherapies, which leads to poor patient survival. Novel pharmacological strategies to tackle HCC are based on oral multi-kinase inhibitors like sorafenib; however, the clinical use of the drug is restricted due to the limited survival rate and significant side effects, suggesting the existence of a primary or/and acquired drug-resistance mechanism. Because of this hurdle, HCC patients are forced through incomplete therapy. Although multiple approaches have been employed in parallel to overcome multidrug resistance (MDR), the results are varying with insignificant outcomes. In the past decade, cancer immunotherapy has emerged as a breakthrough approach and has played a critical role in HCC treatment. The liver is the main immune organ of the lymphatic system. Researchers utilize immunotherapy because immune evasion is considered a major reason for rapid HCC progression. Moreover, the immune response can be augmented and sustained, thus preventing cancer relapse over the post-treatment period. In this review, we provide detailed insights into the immunotherapeutic approaches to combat MDR by focusing on HCC, together with challenges in clinical translation.

Immunotherapeutic approach for advanced pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the USA and the seventh leading cause of cancer-related death worldwide. Most of the patients' presentation is in advanced stages and remains resistant to currently available standard therapies. An in-depth understanding of PDAC's pathogenesis has shown that immunotherapy could bring about a revolution in the treatment response. Immunotherapy in PDAC appears promising in preclinical studies but failed to show benefits in clinical studies. These novel agents' therapeutic failure can be attributed to multiple variables including the tumor microenvironment, early metastasis, tumor heterogeneity and resistance to therapy. There is a need to develop biomarkers for the patient's stratification and provide individualized treatment to improve treatment outcomes.

Overview of Cellular Immunotherapies within Transfusion Medicine for the Treatment of Malignant Diseases

Over the years, transfusion medicine has developed into a broad, multidisciplinary field that covers different clinical patient services such as apheresis technology and the development of stem cell transplantation. Recently, the discipline has found a niche in development and production of advanced therapy medicinal products (ATMPs) for immunotherapy and regenerative medicine purposes. In clinical trials, cell-based immunotherapies have shown encouraging results in the treatment of multiple cancers and autoimmune diseases. However, there are many parameters such as safety, a high level of specificity, and long-lasting efficacy that still need to be optimized to maximize the potential of cell-based immunotherapies. Thus, only a few have gained FDA approval, while the majority of them are studied in the context of investigator-initiated trials (IITs), where modern, academically oriented transfusion centers can play an important role. In this review, we summarize existing and contemporary cellular immunotherapies, which are already a part of modern transfusion medicine or are likely to become so in the future.

Immunotherapy in Acute Myeloid Leukemia: Where We Stand

In the past few years, our improved knowledge of acute myeloid leukemia (AML) pathogenesis has led to the accelerated discovery of new drugs and the development of innovative therapeutic approaches. The role of the immune system in AML development, growth and recurrence has gained increasing interest. A better understanding of immunological escape and systemic tolerance induced by AML blasts has been achieved. The extraordinary successes of immune therapies that harness the power of T cells in solid tumors and certain hematological malignancies have provided new stimuli in this area of research. Accordingly, major efforts have been made to develop immune therapies for the treatment of AML patients. The persistence of leukemia stem cells, representing the most relevant cause of relapse, even after allogeneic stem cell transplant (allo-SCT), remains a major hurdle in the path to cure for AML patients. Several clinical trials with immune-based therapies are currently ongoing in the frontline, relapsed/refractory, post-allo-SCT and minimal residual disease/maintenance setting, with the aim to improve survival of AML patients. This review summarizes the available data with immune-based therapeutic modalities such as monoclonal antibodies (naked and conjugated), T cell engagers, adoptive T-cell therapy, adoptive-NK therapy, checkpoint blockade via PD-1/PD-L1, CTLA4, TIM3 and macrophage checkpoint blockade via the CD47/SIRPa axis, and leukemia vaccines. Combining clinical results with biological immunological findings, possibly coupled with the discovery of biomarkers predictive for response, will hopefully allow us to determine the best approaches to immunotherapy in AML.

Isolation, purification, structural characteristics, pharmacological activities, and combined action of Hedyotis diffusa polysaccharides: A review

Hedyotis diffusa polysaccharides, as the main component and an important bioactive substance of Hedyotis diffusa, are effective immunomodulators with various pharmacological activities, including antitumour, anti-inflammatory, antioxidant, anti-fatigue and immunity-enhancing activities. The total polysaccharides extracted from Hedyotis diffusa and Scutellaria barbata have great effects in treating liver cancer, gastric cancer, rectal cancer, glioma and nasopharyngeal carcinoma. Moreover, different materials and extraction methods result in differences in the structure and bioactivity of Hedyotis diffusa polysaccharides. Therefore, this paper summarizes the isolation, purification, structural characteristics, pharmacological activities, and combined action of Hedyotis diffusa polysaccharides to provide a reference for further study.

Dendritic Cell-Based Immunotherapy in Lung Cancer

Lung cancer remains the leading cause of cancer-related death worldwide. The advent of immune checkpoint inhibitors has led to a paradigm shift in the treatment of metastatic non-small cell and small cell lung cancer. However, despite prolonged overall survival, only a minority of the patients derive clinical benefit from these treatments suggesting that the full anti-tumoral potential of the immune system is not being harnessed yet. One way to overcome this problem is to combine immune checkpoint blockade with different strategies aimed at inducing or restoring cellular immunity in a tumor-specific, robust, and durable way. Owing to their unique capacity to initiate and regulate T cell responses, dendritic cells have been extensively explored as tools for immunotherapy in many tumors, including lung cancer. In this review, we provide an update on the nearly twenty years of experience with dendritic cell-based immunotherapy in lung cancer. We summarize the main results from the early phase trials and give an overview of the future perspectives within this field.

Immunotherapy of gastric cancer: Past, future perspective and challenges

Gastric cancer is considered as the third leading cause of deaths and the fifth most common cancers worldwide. Common treatment approaches include chemotherapy, radiation, gastric resection and targeted therapies. The emergence of gastric cancer immunotherapy has already shown some promising results and have altered the therapeutic procedures. Now, different combination therapies as well as novel immunotherapies targeting new molecules have been proposed. Despite ongoing investigations on the therapeutic options and significant advancements in this regard, the disease is poorly prognosed. In fact, limited therapeutic options and delayed diagnosis lead to the progression, dissemination and metastasis of the disease. Current immunotherapies are mostly based on cytotoxic immunocytes, monoclonal antibodies and gene transferred vaccines. The use of Immune checkpoint inhibitors (ICIs) have grown rapidly. In this review, we aimed to explore perspective and progression of different approaches of immunotherapy in the treatment of GC and the clinical outcomes reported so far. We also summarized the tumor immunosurveillance and tumor immunoescape.

Immunotherapy for Ovarian Cancer: Adjuvant, Combination, and Neoadjuvant

Ovarian cancer is the most lethal gynecologic malignancy. Surgery and chemotherapy are the primary treatments for ovarian cancer; however, patients often succumb to recurrence with chemotherapeutic resistance within several years after the initial treatment. In the past two decades, immunotherapy has rapidly developed, and has revolutionized the treatment of various types of cancer. Despite the fact that immunotherapy response rates among ovarian cancer patients remain modest, treatment with immune checkpoint inhibitors (ICIs), chimeric antigen receptor (CAR)- and TCR-engineered T cells is rapidly developing. Therapeutic efficiency could be improved significantly if immunotherapy is included as an adjuvant therapy, in combination with chemotherapy, radiation therapy, and the use of anti-angiogenesis drugs, and poly ADP ribose polymerase inhibitors (PARPi). Newly developed technologies that identify therapeutic targets, predict treatment efficacy, rapidly screen potential immunotherapy drugs, provide neoadjuvant immunotherapy, and utilize nanomedicine technology provide new opportunities for the treatment of ovarian cancer, and have the potential to prolong patient survival. However, important issues that may hinder the efficacy of such approaches, including hyperprogressive disease (HPD), immunotherapy-resistance, and toxicity of the treatments, including neurotoxicity, must be taken into account and addressed for these therapies to be effective.

Combining epigenetic and immune therapy to overcome cancer resistance

Cancer undergoes "immune editing" to evade destruction by cells of the host immune system including natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). Current adoptive cellular immune therapies include CAR T cells and dendritic cell vaccines, strategies that have yet to show success for a wide range of tumors. Cancer resistance to immune therapy is driven by extrinsic factors and tumor cell intrinsic factors that contribute to immune evasion. These extrinsic factors include immunosuppressive cell populations such as regulatory T cells (Tregs), tumor-associated macrophages (TAMS), and myeloid-derived suppressor cells (MDSCs). These cells produce and secrete immunosuppressive factors and express inhibitory ligands that interact with receptors on T cells including PD-1 and CTLA-4. Immune checkpoint blockade (ICB) therapies such as anti-PD-1 and anti-CTLA-4 have shown success by increasing immune activation to eradicate cancer, though both primary and acquired resistance remain a problem. Tumor cell intrinsic factors driving primary and acquired resistance to these immune therapies include genetic and epigenetic mechanisms. Epigenetic therapies for cancer including DNA methyltransferase inhibitors (DNMTi), histone deacetylase inhibitors (HDACi), and histone methyltransferase inhibitors (HMTi) can stimulate anti-tumor immunity in both tumor cells and host immune cells. Here we discuss in detail tumor mechanisms of immune evasion and how common epigenetic therapies for cancer may be used to reverse immune evasion. Lastly, we summarize current clinical trials combining epigenetic therapies with immune therapies to reverse cancer immune resistance mechanisms.

Designing novel immunocombinations in metastatic renal cell carcinoma

Immune checkpoint inhibitors have radically changed the treatment approach to metastatic renal cell carcinoma (mRCC). In the present article, we reported and discussed the available data with immunocombinations in mRCC, offering new perspectives in the treatment landscape of these patients. We discussed the main results of pivotal clinical trials of immune checkpoint inhibitors in the treatment of mRCC. Moreover, we discussed novel immuno-based treatments currently under investigation in ongoing clinical trials. Renal cell carcinoma is a particularly immunogenic tumor and immunotherapy is a pivotal treatment approach. A wide series of clinical trials is exploring novel promising immunocombinations in patients with renal cell carcinoma.

Cryopreservation of peripheral blood mononuclear cells using uncontrolled rate freezing

Peripheral blood mononuclear cells are widely used as source material for anticancer immunotherapies. The conventional cryopreservation method for peripheral blood mononuclear cells is time-consuming and expansive, which involves controlled rate freezing followed by storage in liquid nitrogen. Instead, the convenient uncontrolled rate freezing cryopreservation method had been reported successfully in peripheral blood hematopoietic stem cells and peripheral blood progenitor cells. Therefore, we hypothesized that uncontrolled rate freezing cooling method maybe also applied to peripheral blood mononuclear cells cryopreservation. In this study, we evaluated the performance of uncontrolled rate freezing and controlled rate freezing cooling methods through cell recovery rate, viability, differentiation potential into cytokine-induced killer cells and the cellular properties of the cultured cytokine-induced killer cells. The results showed similar post-thaw viability and recovery rate in both controlled rate freezing and uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells. Importantly, the uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells exhibited higher growth ratio and earlier cell clustering during ex-vivo cytokine-induced killer cell culture than the controlled rate freezing ones. These two groups of expanded cytokine-induced killer cells also exhibited similar effector cell subset ratio and tumoricidal activity. In general, the performance of cryopreserved peripheral blood mononuclear cells using uncontrolled rate freezing cooling method, with the commercial cryoprotective agent CellBanker 2, was equal or better than the controlled rate freezing method. Our study implied that the combined use of cryoprotective agent CellBanker 2 and uncontrolled rate freezing could be a convenient cryopreservation method for peripheral blood mononuclear cells.

Cellular immunotherapy plus chemotherapy ameliorates survival in gastric cancer patients: a meta-analysis

The efficacy of cellular immunotherapy plus chemotherapy in treatment of gastric cancer (GC) remains inconsistent even controversial. Hence, we performed a meta-analysis to better comprehend the clinical value of cellular immunotherapy plus chemotherapy for GC patients. We searched PubMed, Embase and EBSCO databases to identify the studies evaluating the association of cellular immunotherapy plus chemotherapy and overall survival (OS) and/or disease-free survival (DFS) in patients with GC, and then combined relevant data into hazard ratios (HRs) for OS, DFS and clinicopathological features such as TNM stage, etc. with STATA 12.0. Eleven studies with 1244 patients were included in this meta-analysis. We found that cellular immunotherapy plus chemotherapy remarkably improved overall survival (OS) and diseases-free survival (DFS) as compared to the chemotherapy for GC patients. In subgroup analyses, pooled data showed that the combined therapy was significantly associated with better 3-year and 5-year survival rate, but not with 1-year survival rate of patients; the application of cellular immunotherapy based on either CIK or DC-CIK cells could enhance survival as well as NK, γδT and CIK cells-based immunotherapy. More importantly, the addition of cellular immunotherapy considerably improved OS and DFS only in patients with stage III rather than stage II. In addition, we also discovered that the combined therapy did not cause intolerable side effects to patients. Cellular immunotherapy plus chemotherapy ameliorates survival in GC, especially in patients with stage III, implicating that it is a valuable therapeutic strategy for these patients.

Ten-year update of the international registry on cytokine-induced killer cells in cancer immunotherapy

Cytokine-induced killer (CIK) cells represent an exceptional T-cell population uniting a T cell and natural killer cell-like phenotype in their terminally differentiated CD3⁺ CD56⁺ subset, which features non-MHC-restricted tumor-killing activity. CIK cells have provided encouraging results in initial clinical studies and revealed synergistic antitumor effects when combined with standard therapeutic procedures. We established the international registry on CIK cells (IRCC) to collect and evaluate clinical trials for the treatment of cancer patients in 2010. Moreover, our registry set new standards on the reporting of results from clinical trials using CIK cells. In the present update, a total of 106 clinical trials including 10,225 patients were enrolled in IRCC, of which 4,889 patients in over 30 distinct tumor entities were treated with CIK cells alone or in combination with conventional or novel therapies. Significantly improved median progression-free survival and overall survival were shown in 27 trials, and 9 trials reported a significantly increased 5-year survival rate. Mild adverse effects and graft-versus-host diseases were also observed in the studies. Recently, more efforts have been put into the improvement of antitumoral efficacy by CIK cells including the administration of immune checkpoint inhibitors and modification with chimeric antigen receptorc. The minimal toxicity and multiple improvements on their tumor-killing activity both make CIK cells a favorable therapeutic tool in the clinical practice of cancer immunotherapy.

Targeting CD33 in Chemoresistant AML Patient-Derived Xenografts by CAR-CIK Cells Modified with an Improved SB Transposon System

The successful implementation of chimeric antigen receptor (CAR)-T cell therapy in the clinical context of B cell malignancies has paved the way for further development in the more critical setting of acute myeloid leukemia (AML). Among the potentially targetable AML antigens, CD33 is insofar one of the main validated molecules. Here, we describe the feasibility of engineering cytokine-induced killer (CIK) cells with a CD33.CAR by using the latest optimized version of the non-viral Sleeping Beauty (SB) transposon system "SB100X-pT4." This offers the advantage of improving CAR expression on CIK cells, while reducing the amount of DNA transposase as compared to the previously employed "SB11-pT" version. SB-modified CD33.CAR-CIK cells exhibited significant antileukemic activity in vitro and in vivo in patient-derived AML xenograft models, reducing AML development when administered as an "early treatment" and delaying AML progression in mice with established disease. Notably, by exploiting an already optimized xenograft chemotherapy model that mimics human induction therapy in mice, we demonstrated for the first time that CD33.CAR-CIK cells are also effective toward chemotherapy resistant/residual AML cells, further supporting its future clinical development and implementation within the current standard regimens.

Killers at the crossroads: The use of innate immune cells in adoptive cellular therapy of cancer

Adoptive cell therapy (ACT) is an approach to cancer treatment that involves the use of antitumor immune cells to target residual disease in patients after completion of chemo/radiotherapy. ACT has several advantages compared with other approaches in cancer immunotherapy, including the ability to specifically expand effector cells in vitro before selection for adoptive transfer, as well as the opportunity for host manipulation in order to enhance the ability of transferred cells to recognize and kill established tumors. One of the main challenges to the success of ACT in cancer clinical trials is the identification and generation of antitumor effector cells with high avidity for tumor recognition. Natural killer (NK) cells, cytokine‐induced killers and natural killer T cells are key innate or innate‐like effector cells in cancer immunosurveillance that act at the interface between innate and adaptive immunity, to have a greater influence over immune responses to cancer. In this review, we discuss recent studies that highlight their potential in cancer therapy and summarize clinical trials using these effector immune cells in adoptive cellular therapy for the treatment of cancer.

Recent Advances in Immunotherapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death since most patients are diagnosed at advanced stage and the current systemic treatment options using molecular-targeted drugs remain unsatisfactory. However, the recent success of cancer immunotherapies has revolutionized the landscape of cancer therapy. Since HCC is characterized by metachronous multicentric occurrence, immunotherapies that induce systemic and durable responses could be an appealing treatment option. Despite the suppressive milieu of the liver and tumor immunosurveillance escape mechanisms, clinical studies of checkpoint inhibitors in patients with advanced HCC have yielded promising results. Here, we provide an update on recent advances in HCC immunotherapies. First, we describe the unique tolerogenic properties of hepatic immunity and its interaction with HCC and then review the status of already or nearly available immune checkpoint blockade-based therapies as well as other immunotherapy strategies at the preclinical or clinical trial stage.

Maintenance therapy with ex vivo expanded lymphokine-activated killer cells and rituximab in patients with follicular lymphoma is safe and may delay disease progression

Anti-cluster of differentiation 20 (CD20) monoclonal antibodies (mAbs) have shown promise in follicular lymphoma (FL) as post-induction therapy, by enhancing antibody-dependent cellular cytotoxicity (ADCC). However, cytotoxic cells are reduced after this treatment. We hypothesised that ex vivo expanded lymphokine-activated killer (LAK) cells administered to FL-remission patients are safe and improve anti-CD20 efficacy. This open, prospective, phase II, single-arm study assessed safety and efficacy of ex vivo expanded LAK cells in 20 FL-remission patients following rituximab maintenance. Mononuclear cells were obtained in odd rituximab cycles and stimulated with interleukin 2 (IL-2) for 8 weeks, after which >5 × 10⁸ LAK cells were injected. Patients were followed-up for 5 years. At the end of maintenance, peripheral blood cells phenotype had not changed markedly. Natural killer, LAK and ADCC activities of mononuclear cells increased significantly after recombinant human IL-2 (rhIL-2) stimulation in all cycles. Rituximab significantly enhanced cytotoxic activity. No patients discontinued treatment. There were no treatment-related serious adverse events. Three patients had progressed by the end of follow-up. After a median (interquartile range) follow-up of 59.4 (43.8-70.9) months, 85% of patients remained progression free. No deaths occurred. Quality-of-life improved throughout the study. Post-induction LAK cells with rituximab seem safe in the long term. Larger studies are warranted to confirm efficacy.

Advances in Targeting the Innate and Adaptive Immune Systems to Cure Chronic Hepatitis B Virus Infection

“Functional cure” is being pursued as the ultimate endpoint of antiviral treatment in chronic hepatitis B (CHB), which is characterized by loss of HBsAg whether or not anti-HBs antibodies are present. “Functional cure” can be achieved in <10% of CHB patients with currently available therapeutic agents. The dysfunction of specific immune responses to hepatitis B virus (HBV) is considered the major cause of persistent HBV infection. Thus, modulating the host immune system to strengthen specific cellular immune reactions might help eliminate HBV. Strategies are needed to restore/enhance innate immunity and induce HBV-specific adaptive immune responses in a coordinated way. Immune and resident cells express pattern recognition receptors like TLRs and RIG I/MDA5, which play important roles in the induction of innate immunity through sensing of pathogen-associated molecular patterns (PAMPs) and bridging to adaptive immunity for pathogen-specific immune control. TLR/RIG I agonists activate innate immune responses and suppress HBV replication in vitro and in vivo, and are being investigated in clinical trials. On the other hand, HBV-specific immune responses could be induced by therapeutic vaccines, including protein (HBsAg/preS and HBcAg), DNA, and viral vector-based vaccines. More than 50 clinical trials have been performed to assess therapeutic vaccines in CHB treatment, some of which display potential effects. Most recently, using genetic editing technology to generate CAR-T or TCR-T, HBV-specific T cells have been produced to efficiently clear HBV. This review summarizes the progress in basic and clinical research investigating immunomodulatory strategies for curing chronic HBV infection, and critically discusses the rather disappointing results of current clinical trials and future strategies.

Impact of FAK Expression on the Cytotoxic Effects of CIK Therapy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a special subtype of breast cancer in which several common diagnostic biomarkers are lost. Due to the loss of expression of receptors, treatment options for TNBC are limited. Therefore, finding safe and effective treatments for patients with TNBC is a major objective for clinicians. Previous studies suggested that cytokine-induced killer (CIK) cells may be beneficial for patients with a variety of tumor types. However, CIK therapy is not effective for all patients. In this study, we found that focal adhesion kinase (FAK), a non-receptor protein tyrosine kinase that regulates several cellular functions in different cells, has the potential to regulate tumor cells sensitized to CIK cells. Knockdown of FAK expression in TNBC cells or the treatment of TNBC cells with a FAK inhibitor followed by coculture with CIK cells increases death of TNBC cells, suggesting that FAK plays important roles in sensitizing tumor cells to CIK cells. This phenomenon could be regulated by a FAK-programmed death-ligand 1 (PD-L1)-related mechanism. Overall, our findings provide new insights into the cytotoxic effect of CIK cell therapy in TNBC treatment, and show that CIK cell therapy combined with FAK inhibitors may be a novel therapeutic strategy for patients with TNBC.

Herbal Medicines Attenuate PD-L1 Expression to Induce Anti-Proliferation in Obesity-Related Cancers

Pro-inflammatory hormones and cytokines (leptin, tumor necrosis factor (TNF)-α, and interleukin (IL)-6) rise in obesity. Elevated levels of hormones and cytokines are linked with several comorbidities such as diabetes, heart disease, and cancer. The checkpoint programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) plays an important role in obesity and cancer proliferation. L-thyroxine (T₄) and steroid hormones up-regulate PD-L1 accumulation and promote inflammation in cancer cells and diabetics. On the other hand, resveratrol and other herbal medicines suppress PD-L1 accumulation and reduce diabetic effects. In addition, they induce anti-cancer proliferation in various types of cancer cells via different mechanisms. In the current review, we discuss new findings and visions into the antagonizing effects of hormones on herbal medicine-induced anti-cancer properties.

Targeting the TIGIT-PVR immune checkpoint axis as novel therapeutic option in breast cancer

Immune checkpoints are intensively investigated as targets in cancer therapy. T-cell immunoreceptor with immunoglobulin (Ig) and ITIM domains (TIGIT) and its ligand poliovirus receptor (PVR) are recently emerging as novel promising targets in immunotherapy. Here, we show that high expression of PVR represents an independent prognostic marker being associated with poor outcome for breast cancer patients. Furthermore, PVR mRNA, as well as protein expression, is associated with more aggressive breast cancer subtypes such as HER2 positive and triple-negative breast cancer. In vitro, blocking TIGIT or PVR resulted in enhanced immune cell-mediated lysis of breast cancer cell lines SKBR-3, MDA-MB-231, MDA-MB-468, and BT549 and additionally increased the cytotoxic effects of a bispecific T cell engager BiTE® antibody construct targeting EGFR. Taken together, our data identify the immune checkpoint factor PVR as a novel prognostic marker in breast cancer and indicate that blocking the TIGIT-PVR axis might represent a novel therapeutic option for the treatment of breast cancer patients.

Cryoablation and Immunotherapy: An Enthralling Synergy to Confront the Tumors

Treatment of solid tumors by ablation techniques has gained momentum in the recent years due to their technical simplicity and reduced morbidity as juxtaposed to surgery. Cryoablation is one of such techniques, known for its uniqueness to destroy the tumors by freezing to lethal temperatures. Freezing the tumor locally and allowing it to remain in situ unleashes an array of tumor antigens to be exposed to the immune system, paving the way for the generation of anti-tumor immune responses. However, the immune responses triggered in most cases are insufficient to eradicate the tumors with systemic spread. Therefore, combination of cryoablation and immunotherapy is a new treatment strategy currently being evaluated for its efficacy, notably in patients with metastatic disease. This article examines the mechanistic fabric of cryoablation for the generation of an effective immune response against the tumors, and various possibilities of its combination with different immunotherapies that are capable of inducing exceptional therapeutic responses. The combinatorial treatment avenues discussed in this article if explored in sufficient profundity, could reach the pinnacle of future cancer medicine.

The biological macromolecule Nocardia rubra cell-wall skeleton as an avenue for cell-based immunotherapy

Promoting the antitumor effects of cell-based immunotherapy for clinical application remains a difficult challenge. Nocardia rubra cell-wall skeleton (N-CWS) is an immunotherapeutic agent for cancers that have been proven to possess the ability to activate immune response without showing toxicity. However, its effects on immune cells that are derived from tumor patients and cultured in vitro remain unclear. As expected, N-CWS can enhance the proliferation and viability of cytokine-induced killer (CIK) cells, dendritic cells (DCs), and natural killer (NK) cells. The maturation of DCs and specific cytotoxicity against NK cells and CIK cells were consistently promoted. The TUNEL-staining and the Annexin V/propidium iodide assay revealed that after treatment with N-CWS, the stimulated CIK/NK cells could induce DNA breaks in tumor cells. Furthermore, quantitative real-time polymerase chain reaction and western blot analysis showed upregulation of proapoptotic biomarkers (caspase-3 and caspase-9) and a downregulation of the antiapoptotic biomarker Bcl-2 in the tumor cells of the N-CWS-treated group, indicating that N-CWS could induce hepatocellular carcinoma cell apoptosis via CIK/NK cells. Finally, CIK/NK cells could notably suppress the invasion and migration of tumor cells in the presence of N-CWS. Our study provides evidence that N-CWS could significantly increase the growth of CIK cells, DCs, and NK cells, particularly due to its robust antitumor activities by inducing apoptosis, and attenuate the invasion and migration of tumor cells.

PD-L1 expression is a predictive biomarker for CIK cell-based immunotherapy in postoperative patients with breast cancer

Background

A sequential combination of radiochemotherapy/endocrinotherapy and cytokine-induced killer cell (CIK) infusion has been shown to be an effective therapy for post-mastectomy breast cancer based on statistical analysis of the patient population. However, whether an individual could obtain an improved prognosis from CIK cell-based treatment remains unknown. In the present study, we focused on immune microenvironment regulation and specifically investigated the relationship between PD-L1 expression and survival benefit from CIK immunotherapy in breast cancer.

Methods

A total of 310 postoperative breast cancer patients who received comprehensive treatment were enrolled in this retrospective study, including 160 patients in the control group (received chemotherapy/radiotherapy/endocrinotherapy) and 150 patients in the CIK cell treatment group (received chemotherapy/radiotherapy/ endocrinotherapy and subsequent CIK infusion).

Results

We found that overall survival (OS) and recurrence-free survival (RFS) were significantly better in the CIK group than that in the control group. PD-L1 expression in tumor tissue sections was showed to be an independent prognostic factor for patients in the CIK treatment group using multivariate survival analysis. Further survival analysis in the CIK group showed that patients with PD-L1 tumor expression exhibited longer OS and RFS. In addition, among all patients who were enrolled in this study, only the patients with PD-L1 expression experienced survival benefits from CIK treatment.

Conclusions

Our study showed the relationship between PD-L1 expression and CIK therapy and revealed that PD-L1 expression in the tumor is as an indicator of adjuvant CIK therapy for postoperative breast cancer.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0696-8) contains supplementary material, which is available to authorized users.

Mouse CD8+NKT-like cells exert dual cytotoxicity against mouse tumor cells and myeloid-derived suppressor cells

Our previous work has demonstrated the high efficiency of CD8⁺ natural killer T (NKT)-like cells in killing antigen-bearing dendritic cells. To evaluate their role in the tumor microenvironment, we performed in vitro and in vivo antitumor experiments to investigate whether CD8⁺NKT-like cells could kill Yac-1 and B16 cells like NK cells and kill EL4-OVA8 cells in an antigen-specific manner like cytotoxic T lymphocytes (CTLs). Unlike NK1.1⁻CTLs, CD8⁺NKT-like cells also exhibit the capability to kill myeloid-derived suppressor cells (MDSCs) in an antigen-specific manner, indicative of their potential role in clearing tumor antigen-bearing MDSCs to improve the antitumor microenvironment. In vitro blocking experiments showed that granzyme B inhibitor efficiently suppressed the cytotoxicity of CD8⁺NKT-like cells against tumor cells and MDSCs, while Fas ligand (FasL) or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) inhibition failed to produce similar effects. Transcriptomic and phenotypic analyses of CD8⁺NKT-like cells, NK cells, and NK1.1⁻CTLs indicated that CD8⁺NKT-like cells expressed both T-cell activation markers and NK cell markers, thus bearing features of both the activated T cells and NK cells. Taken together, CD8⁺NKT-like cells could exert NK- and CTL-like antitumor effects through the elimination of both tumor cells and MDSCs in a granzyme B-dependent manner.

Bispecific T-Cell Redirection versus Chimeric Antigen Receptor (CAR)-T Cells as Approaches to Kill Cancer Cells

The concepts for T-cell redirecting bispecific antibodies (TRBAs) and chimeric antigen receptor (CAR)-T cells are both at least 30 years old but both platforms are just now coming into age. Two TRBAs and two CAR-T cell products have been approved by major regulatory agencies within the last ten years for the treatment of hematological cancers and an additional 53 TRBAs and 246 CAR cell constructs are in clinical trials today. Two major groups of TRBAs include small, short-half-life bispecific antibodies that include bispecific T-cell engagers (BiTE®s) which require continuous dosing and larger, mostly IgG-like bispecific antibodies with extended pharmacokinetics that can be dosed infrequently. Most CAR-T cells today are autologous, although significant strides are being made to develop off-the-shelf, allogeneic CAR-based products. CAR-Ts form a cytolytic synapse with target cells that is very different from the classical immune synapse both physically and mechanistically, whereas the TRBA-induced synapse is similar to the classic immune synapse. Both TRBAs and CAR-T cells are highly efficacious in clinical trials but both also present safety concerns, particularly with cytokine release syndrome and neurotoxicity. New formats and dosing paradigms for TRBAs and CAR-T cells are being developed in efforts to maximize efficacy and minimize toxicity, as well as to optimize use with both solid and hematologic tumors, both of which present significant challenges such as target heterogeneity and the immunosuppressive tumor microenvironment.

Dendritic cell/cytokine-induced killer cell-based immunotherapy in lung cancer: What we know and future landscape

Multiple modalities for lung cancer therapy have emerged in the past decade, whereas their clinical applications and survival-beneficiary is little known. Vaccination with dendritic cells (DCs) or DCs/cytokine-induced killer (CIK) cells has shown limited success in the treatment of patients with advanced non-small-cell lung cancer. To evaluate and overcome these limitations in further studies, in the present review, we sum up recent progress about DCs or DCs/CIKs-based approaches for preclinical and clinical trials in patients with lung cancer and discuss some of the limited therapeutic success. Moreover, this review highlights the need to focus future studies on the development of new approaches for successful immunotherapy in patients with lung cancer.

Immune precision medicine for cancer: a novel insight based on the efficiency of immune effector cells

Cancer cell growth is associated with immune surveillance failure. Nowadays, restoring the desired immune response against cancer cells remains a major therapeutic strategy. Due to the recent advances in biological knowledge, efficient therapeutic tools have been developed to support the best bio-clinical approaches for immune precision therapy. One of the most important successes in immune therapy is represented by the applicational use of monoclonal antibodies, particularly the use of rituximab for B-cell lymphoproliferative disorders. More recently, other monoclonal antibodies have been developed, to inhibit immune checkpoints within the tumor microenvironment that limit immune suppression, or to enhance some immune functions with immune adjuvants through different targets such as Toll-receptor agonists. The aim is to inhibit cancer proliferation by the diminishing/elimination of cancer residual cells and clinically improving the response duration with no or few adverse effects. This effect is supported by enhancing the number, functions, and activity of the immune effector cells, including the natural killer (NK) lymphocytes, NKT-lymphocytes, γδ T-lymphocytes, cytotoxic T-lymphocytes, directly or indirectly through vaccines particularly with neoantigens, and by lowering the functions of the immune suppressive cells. Beyond these new therapeutics and their personalized usage, new considerations have to be taken into account, such as epigenetic regulation particularly from microbiota, evaluation of transversal functions, particularly cellular metabolism, and consideration to the clinical consequences at the body level. The aim of this review is to discuss some practical aspects of immune therapy, giving to clinicians the concept of immune effector cells balancing between control and tolerance. Immunological precision medicine is a combination of modern biological knowledge and clinical therapeutic decisions in a global vision of the patient.

Enhanced metabolic activities for ATP production and elevated metabolic flux via pentose phosphate pathway contribute for better CIK cells expansion

Objective

Ex vivo expansion is an effective way to produce cytokine‐induced killer (CIK) cells needed for clinical trials. Here, ex vivo expansion and metabolism characters of CIK cells in static and dynamic cultures and the relationship between cell expansion and metabolism were investigated.

Materials and methods

Oxygen transfer efficiency was assessed by computational fluid dynamics technique. Cell phenotype, apoptosis and of transporter expression were determined by flow cytometry and Western blotting. Metabolites and enzyme activities were assessed by biochemical methods.

Results

Dynamic cultures favoured better CIK cell expansion without impairing their phenotype and cytotoxicity, enhanced oxygen transfer efficiency. The glucose metabolism flux of cells in dynamic cultures was enhanced by upregulating surface glucose transporter 1 expression and phosphofructokinase activity. Moreover, pentose phosphate pathway (PPP) metabolic flux was enhanced through upregulating glucose‐6‐phosphate dehydrogenase activity. Glutaminolysis was also accelerated via boosting glutamine transporters expression, glutaminase (GLS) and glutamate dehydrogenase activities. Together with higher oxygen consumption rate and extracellular acidification rate, it was suggested that cells in dynamic cultures were in a more vigorous metabolic state for ATP production.

Conclusion

Dynamic cultures accelerated glucose and glutamine metabolic flux to promote ATP production, elevated glucose metabolic flux through PPP to promote biosynthesis for better cell expansion. These findings may provide the basis for ex vivo CIK cell expansion process optimization.

Targeting the crosstalk between cytokine-induced killer cells and myeloid-derived suppressor cells in hepatocellular carcinoma

BACKGROUND & AIMS

Cytokine-induced killer (CIK) cell-based immunotherapy is effective as an adjuvant therapy in early stage hepatocellular carcinoma (HCC) but lacks efficacy in advanced HCC. We aimed to investigate immune suppressor mechanisms in HCC, focusing on the role of myeloid-derived suppressor cells (MDSCs) in response to CIK therapy.

METHODS

MDSCs were quantified by flow cytometry and quantitative real-time PCR. Cytokines were detected by cytokine array. A lactate dehydrogenase cytotoxicity assay was performed in the presence or absence of MDSCs to study CIK function against HCC cells in vitro. An FDA-approved PDE5 inhibitor, tadalafil, was used to target MDSCs in vitro and in vivo. Two different murine HCC cell lines were tested in subcutaneous and orthotopic tumor models in C57BL/6 and BALB/c mice. The antitumor effects of human CIKs and MDSCs were also tested in vitro.

RESULTS

Adoptive cell transfer of CIKs into tumor-bearing mice induced inflammatory mediators (e.g., CX3CL1, IL-13) in the tumor microenvironment and an increase of tumor-infiltrating MDSCs, leading to impaired antitumor activity in 2 different HCC models. MDSCs efficiently suppressed the cytotoxic activity of CIKs in vitro. In contrast, treatment with a PDE5 inhibitor reversed the MDSC suppressor function via ARG1 and iNOS blockade and systemic treatment with a PDE5 inhibitor prevented MDSC accumulation in the tumor microenvironment upon CIK cell therapy and increased its antitumor efficacy. Similar results were observed when human CIKs were tested in vitro in the presence of CD14⁺HLA-DR^-/low MDSCs. Treatment of MDSCs with a PDE5 inhibitor suppressed MDSC suppressor function and enhanced CIK activity against human HCC cell lines in vitro.

CONCLUSION

Our results suggest that targeting MDSCs is an efficient strategy to enhance the antitumor efficacy of CIKs for the treatment of patients with HCC.

LAY SUMMARY

Cytokine-induced killer cells are a mixture of immune cells given to eliminate cancer cells. However, not all patients respond to this treatment. Herein, we show in 2 different liver cancer models that myeloid-derived suppressor cells are increased in response to cytokine-induced killer cell therapy. Targeting these myeloid-derived suppressor cells may provide an additional therapeutic benefit alongside cytokine-induced killer cell therapy.

High-affinity T cell receptors redirect cytokine-activated T cells (CAT) to kill cancer cells

Cytokine-activated T cells (CATs) can be easily expanded and are widely applied to cancer immunotherapy. However, the good efficacy of CATs is rarely reported in clinical applications because CATs have no or very low antigen specificity. The low-efficacy problem can be resolved using T cell antigen receptor-engineered CAT (TCR-CAT). Herein, we demonstrate that NY-ESO-1_157-165 HLA-A*02:01-specific high-affinity TCR (HAT)-transduced CATs can specifically kill cancer cells with good efficacy. With low micromolar range dissociation equilibrium constants, HAT-transduced CATs showed good specificity with no off-target killing. Furthermore, the high-affinity TCR-CATs delivered significantly better activation and cytotoxicity than the equivalent TCR-engineered T cells (TCR-Ts) in terms of interferon-γ and granzyme B production and in vitro cancer cell killing ability. TCR-CAT may be a very good alternative to the expensive TCR-T, which is considered an effective personalized cyto-immunotherapy.

Human double negative T cells target lung cancer via ligand-dependent mechanisms that can be enhanced by IL-15

Background

The advents of novel immunotherapies have revolutionized the treatment of cancer. Adoptive cellular therapies using chimeric antigen receptor T (CAR-T) cells have achieved remarkable clinical responses in B cell leukemia and lymphoma but the effect on solid tumors including lung cancer is limited. Here we present data on the therapeutic potential of allogeneic CD3⁺CD4⁻CD8⁻ double negative T (DNT) cells as a new cellular therapy for the treatment of lung cancer and underlying mechanisms.

Methods

DNTs were enriched and expanded ex vivo from healthy donors and phenotyped by flow cytometry. Functionally, their cytotoxicity was determined against primary and established non-small-cell lung cancer (NSCLC) cell lines in vitro or through in vivo adoptive transfer into xenograft models. Mechanistic analysis was performed using blocking antibodies against various cell surface and soluble markers. Furthermore, the role of IL-15 on DNT function was determined.

Results

We demonstrated that ex vivo expanded DNTs can effectively lyse various human NSCLC cells in vitro and inhibit tumor growth in xenograft models. Expanded DNTs have a cytotoxic phenotype, as they express NKp30, NKG2D, DNAM-1, membrane TRAIL (mTRAIL), perforin and granzyme B, and secrete IFNγ and soluble TRAIL (sTRAIL). DNT-mediated cytotoxicity was dependent on a combination of tumor-expressed ligands for NKG2D, DNAM-1, NKp30 and/or receptors for TRAIL, which differ among different NSCLC cell lines. Furthermore, stimulation of DNTs with IL-15 increased expression of effector molecules on DNTs, their TRAIL production and cytotoxicity against NSCLC in vitro and in vivo.

Conclusion

Healthy donor-derived DNTs can target NSCLC in vitro and in vivo. DNTs recognize tumors via innate receptors which can be up-regulated by IL-15. DNTs have the potential to be used as a novel adoptive cell therapy for lung cancer either alone or in combination with IL-15.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0507-2) contains supplementary material, which is available to authorized users.

Therapeutic Potential of Natural Killer Cells in Gastric Cancer

Gastric cancer (GC) is one of the most common cancers, with a high incidence of cancer death. Despite various therapeutic approaches, the cures and prognosis of advanced GC remain poor. Natural killer (NK) cells, which are known as important lymphocytes in innate immunity, play vital roles in suppressing GC initiation, progression, and metastases. A wide range of clinical settings shows that increasing the number of NK cells or improving NK cell antitumor activity is promising in GC patients. NK cell adoptive therapy (especially expanded NK cells) is a safe and well-tolerated method, which can enhance NK cell cytotoxicity against GC. Meanwhile, cytokines, immunomodulatory drugs, immune checkpoint blockades, antibodies, vaccines, and gene therapy have been found to directly or indirectly activate NK cells to improve their killing activity toward GC. In this review, we summarize recent advancements in the relationship between NK cells and GC and point out all the innovative strategies that can enhance NK cells' function to inhibit the growth of GC.

Targeted and Immune-Based Therapies for Hepatocellular Carcinoma

Treatment options for patients with hepatocellular carcinoma are rapidly changing based on positive results from phase 3 trials of targeted and immune-based therapies. More agents designed to target specific pathways and immune checkpoints are in clinical development. Some agents have already been shown to improve outcomes of patients with hepatocellular carcinoma, as first- and second-line therapies, and are awaiting approval by the Food and Drug Administration or have been recently approved. We summarize the targeted and immune-based agents in trials of patients with advanced hepatocellular carcinoma and discuss the future of these strategies for liver cancer.

Promising immunotherapy: Highlighting cytokine-induced killer cells

For many years, cancer therapy has appeared to be a challenging issue for researchers and physicians. By the introduction of novel methods in immunotherapy, the prospect of cancer therapy even more explained than before. Cytokine-induced killer (CIK) cell-based immunotherapy demonstrated to have potentiality in improving clinical outcomes and relieving major side effects of standard treatment options. In addition, given the distinctive features such as high safety, low toxicity effects on healthy cells, numerous clinical trials conducted on CIK cells. Due to the shortcomings that observed in CIK cell immunotherapy alone, arising a tendency to make modifications (combined modality therapy or combination therapy) including the addition of various types of cytokines, genetic engineering, combination with immune checkpoints, and so on. In this review, we have tried to bring forth the latest immunotherapy methods and their overview. We have discussed the combination therapies with CIK cells and the conducted clinical trials. This helps the future studies to use integrated therapies with CIK cells as a promising treatment of many types of cancers.

Programmed cell death protein-1/programmed death-ligand 1 blockade enhances the antitumor efficacy of adoptive cell therapy against non-small cell lung cancer

Background

Cytokine-induced killer (CIK) cells and natural killer (NK) cells are employed by two different approaches to adoptive cell immunotherapy for cancer. It has been reported that adoptive cell immunotherapy could prolong the overall survival (OS) of advanced cancer patients. The introduction of agents that induce immune checkpoint blockades has improved the efficacy of immune-mediated therapy for metastatic cancers. However, the effects of combining a checkpoint inhibitor with CIK cells or NK cells to target non-small cell lung cancer (NSCLC)remain unknown.

Methods

The present study investigated the effects of combining CIK cells with a programmed cell death protein-1 (PD-1) inhibitor (an anti-PD-1 monoclonal antibody). During the expansion cultivation, the addition of the PD-1 antibody promoted CIK-mediated cytotoxicity in H1975 lung adenocarcinoma cells. Co-cultivation of CIK cells with the PD-1 antibody for 6 days induced CD3⁺CD56⁺ T cell expansion, with increases in the levels of CD107a and interferon γ (IFN-γ).

Results

When NK cells were co-cultured with 5 µg/mL of an anti-programmed death-ligand 1 (PD-L1) mAb for 24 hours at an effector cell: target ratio of 10:1, it led to more potent cytotoxicity compared to other time points and concentrations. However, combining NK cells with the anti-PD-L1 mAb showed no significant advantages over treatment with NK cells alone.

Conclusions

Our results suggest that combining CIK cells with PD-1 blockade before transfusion might improve the efficiency of CIK therapy for NSCLC patients. This effect does not seem to occur for NK cell therapy.

Retrospective analysis of the efficacy of adjuvant CIK cell therapy in epithelial ovarian cancer patients who received postoperative chemotherapy

Cytokine-induced killer (CIK) cells are demonstrated to possess potent cytolytic effect against ovarian cancer cells in vitro and in vivo. However, the clinical efficacy of maintenance therapy of CIK cells in patients with epithelial ovarian cancer (EOC) after first-line treatment remains unclear. This retrospective study included 646 cases of postoperative EOC patients, 72 of which received chemotherapy and sequential immunotherapy (CIT group), and 574 of which received only chemotherapy (Control group). Patients in the CIT group received at least four cycles of CIK cell (range 8.0 × 10⁹ – 1.3 × 10¹⁰ cells) transfusion, with the interval of each cycle being 2 weeks. Survival analysis showed a significantly higher overall survival (OS) rate in the CIT group compared with the control group, as well as a favorable progression-free survival (PFS). Univariate and multivariate analyses indicated that adjuvant CIT was an independent prognostic factor for the OS of patients with EOC. Furthermore, subgroup analyses showed that adjuvant CIT significantly improved the OS of patients older than 45 years, with CA125 ≤ 1000, or with moderate or poorly differentiated tumors, and prolonged the PFS of patients with residual disease > 1 cm. Additionally, Kaplan-Meier analyses revealed that a higher fraction of CD3⁺CD8⁺/CD3⁺CD56⁺ phenotypes or lower percentage of CD3⁺CD4⁺/CD3⁻CD56⁺ phenotypes in the infused CIK cells significantly associated with better survival of patients with EOC. Furthermore, across all processes of CIK cell immunotherapy in the CIT group, 12.5% (9/72) of patients developed self-limiting light fevers and shivering at grade 1 or 2. No immunotherapy-related serious reactions were recorded. These data indicate that adjuvant CIT with CIK cells is an effective therapeutic approach to prolonging the survival of EOC patients.

Adoptive Cell Transfer: Is it a Promising Immunotherapy for Colorectal Cancer?

The last decade has witnessed significant advances in the adoptive cell transfer (ACT) technique, which has been appreciated as one of the most promising treatments for patients with cancer. Utilization of ACT can enhance the function of the immune system or improve the specificity and persistence of transferred cells. Various immune cells including T lymphocytes, natural killer cells, dendritic cells, and even stem cells can be used in the ACT despite their different functional mechanisms. Colorectal cancer (CRC) is among the most common malignancies and causes millions of deaths worldwide every year. In this review, we discuss the status and perspective of the ACT in the treatment of CRC.

Recombinant Adenovirus KGHV500 and CIK Cells Codeliver Anti-p21-Ras scFv for the Treatment of Gastric Cancer with Wild-Type Ras Overexpression

The development of gastric cancer is frequently related to the overexpression of wild-type p21 proteins, but it is rarely related to mutated Ras proteins. We previously constructed a broad-spectrum anti-p21-Ras single-chain variable fragment antibody (scFv), which was carried by the oncolytic adenovirus KGHV500. Here we explored the antitumor effects of this recombinant oncolytic adenovirus carried by cytokine-induced killer (CIK) cells on human gastric SGC7901 cells that overexpress wild-type Ras. The MTT assay, scratch test, Transwell assay, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed in vitro to investigate the proliferation, migration, invasiveness, and cell apoptosis rate, respectively, of the human gastric cell line SGC7901 treated with KGHV500 adenovirus. Then, the tumor-targeting ability and systemic safety of KGHV500 adenovirus delivered by CIK cells were explored in vivo. We found that KGHV500 adenovirus could significantly inhibit proliferation, migration, and invasiveness and promote cell apoptosis in SGC7901 cells in vitro. In vivo studies showed that CIK cells could successfully deliver KGHV500 adenovirus to the tumor site; the two vectors synergistically killed tumor cells, and the treatment was relatively safe for normal tissues. In conclusion, this therapeutic strategy of recombinant adenovirus KGHV500 delivered by CIK cells offers a positive prospect for the targeted therapy of Ras-related cancers.

Dynamic suspension culture improves ex vivo expansion of cytokine-induced killer cells by upregulating cell activation and glucose consumption rate

Ex vivo expansion is an effective strategy to acquire cytokine-induced killer (CIK) cells needed for clinical trials. In this work, the effects of dynamic suspension culture, which was carried out by shake flasks on a shaker, on CIK cells were investigated by the analysis of expansion characteristics and physiological functions, with the objective to optimize the culture conditions for ex vivo expansion of CIK cells. The results showed that the expansion folds of total cells in dynamic cultures reached 69.36 ± 30.36 folds on day 14, which were significantly higher than those in static cultures (9.24 ± 1.12 folds, P < 0.05), however, the proportions of CD3⁺ cells and CD3⁺CD56⁺ cells in both cultures were similar, leading to much higher expansion of CD3⁺ cells and CD3⁺CD56⁺ cells in dynamic cultures. Additionally, expanded CIK cells in two cultures possessed comparable physiological functions. Notably, significantly higher percentages of CD25⁺ cells and CD69⁺ cells were found in dynamic cultures (P <  0.05). Besides, much higher glucose consumption rate of cells (P <  0.05) but similar Y_Lac/gluc were observed in dynamic cultures. Further, cells in dynamic cultures had better glucose utilization efficiency. Together, these results suggested that dynamic cultures improved cell activation, then accelerated glucose consumption rate, which enhanced cell expansion and promoted glucose utilization efficiency of cells.

Influence of different ex vivo cell culture methods on the proliferation and anti-tumor activity of cytokine-induced killer cells from gastric cancer patients

Purpose

In cytokine-induced killer (CIK) cell therapy, the phenotypes and the numbers of CIK cells have a great influence on the therapeutic effects. This study aimed to investigate the effects of different ex vivo cell culture methods on the proliferation and cytotoxicity of CIK cells that were obtained from gastric cancer patients.

Patients and methods

CIK precursor (Pre-CIK) cells were collected by either hydroxyethyl starch (HES) sedimentation (HES method, unpurified group) or Ficoll-Hypaque density gradient centrifugation (Ficoll method, purified group). Cell number, collection time, and morphology of Pre-CIK cells in the two groups were determined. The proliferation ability, cytokines, phenotypes, and cytotoxicity of CIK cells in the two groups were evaluated ex vivo and in vivo.

Results

In this study, the number of Pre-CIK cells in the unpurified group was significantly higher than that in the purified group (P<0.05). Numbers of erythrocytes, platelets, and granulocytes were reduced significantly following the purification step (P<0.05). Compared to CIK cells in the purified group, those in the unpurified group showed more active proliferation, accompanied by higher percentages of CD8⁺, CD3^-CD56⁺, and CD3⁺CD56⁺ cells, which were responsible for cytotoxicity of CIK cells (P<0.05). This research also showed that the levels of interferon-γ, interleukin-2, and tumor necrosis factor-α, which can enhance the proliferation and cytotoxicity of CIK cells, were significantly increased in the unpurified group (P<0.05). Furthermore, CIK cells in the unpurified group also showed stronger anti-tumor effects against gastric cancer cells than those in the purified group, both ex vivo and in vivo (P<0.05).

Conclusion

The removal of Ficoll-Hypaque purification step reduces the time and cost of the Pre-CIK separation and provides more CIK cells with higher cytotoxicity, which is of great importance in the clinical application of CIK cell therapy.

EphA2 chimeric antigen receptor-modified T cells for the immunotherapy of esophageal squamous cell carcinoma

Background

It is urgent to explore an effective potential therapeutic strategy for ESCC. In recent years, cell-based cancer immunotherapy has become a potentially close for carcinoma therapy. Chimeric antigen receptor (CAR) T cell technology is a kind of adoptive cell therapy technique which has been developed rapidly. We sought to obtain EphA2.CAR-T cell and revealed the ability of EphA2.CAR-T cells to kill esophageal squamous cell carcinoma (ESCC) cells in vitro.

Methods

Firstly, the expression and location of EphA2 in ESCC tissues and cells was tested by immunohistochemistry staining and Western blot. Secondly, the second generation of EphA2.CAR was constructed via molecular biology technology, and transduced into T cells to obtain the EphA2.CAR-T cell. The transduction efficacies were assessed using flow cytometry (FCM). Thirdly, the effect of cell killing of EphA2.CAR-T cell on ESCC cells in vitro was detected by co-culture experiments. The productions of cytokines (TNF-α and IFN-γ) by EphA2.CAR-T cell after co-culture with ESCC cells were analyzed by ELISA assay.

Results

The expression of EphA2 was significantly upregulated in ESCC tissues and cells (P<0.05). EphA2 was expressed on the membrane of ESCC cells, so it could be served as tumor-associated surface antigens (TAA) of CAR for ESCC treatment. The EphA2.CAR-T cell was obtained successfully, and its' transduction efficacies was 61.4% by FCM. The ability of cell killing of EphA2.CAR-T cell was better than that of T cells (P<0.01), and demonstrated a dose-dependent cell killing. The results of ELISA assay showed that the levels of TNF-α and IFN-γ in EphA2.CAR-T cells were notably raised compared with T cells (P<0.05).

Conclusions

We firstly constructed the second generation of EphA2.CAR and established EphA2.CAR-T cells. The EphA2.CAR-T cells showed a dose-dependent cell killing of ESCC cells, and promoted the production of cytokines in vitro. These findings open a new way for treatment of ESCC by immunotherapy in the future.