Cytokine induced killer cells as promising immunotherapy for solid tumors

Three-dimensional dynamics of mesothelin-targeted CAR.CIK lymphocytes against ovarian cancer peritoneal carcinomatosis

Intraperitoneal cellular immunotherapy with CAR-redirected lymphocytes is an intriguing approach to target peritoneal carcinomatosis (PC) from ovarian cancer (OC), which is currently evaluated in clinical trials. PC displays a composite structure with floating tumor cells within ascites and solid-like masses invading the peritoneum. Therefore, a comprehensive experimental model is crucial to optimize CAR-cell therapies in such a peculiar environment. Here, we explored the activity of cytokine-induced killer lymphocytes (CIK), redirected by CAR against mesothelin (MSLN-CAR.CIK), within reductionistic 3D models resembling the structural complexity of both liquid and solid components of PC. MSLN-CAR.CIK effectively killed and were functionally efficient against OC targets. In a "floating-like" 3D context with floating OC spheroids, both tumor localization and killing by MSLN-CAR.CIK were significantly boosted by fluid flow. In a "solid-like" context, MSLN-CAR.CIK were recruited through the extracellular matrix on embedded tumor aggregates, with variable kinetics depending on the effector-target distance. Furthermore, MSLN-CAR.CIK penetrated the inner levels of OC spheroids exerting effective tumor killing. Our findings provide currently unknown therapeutically relevant information on intraperitoneal approaches with CAR.CIK, supporting further developments and improvements for clinical studies in the context of locoregional cell therapy approaches for patients with PC from OC.

Generation of dual-attribute iTNK cells from hPSCs for cancer immunotherapy

Dual-attribute immune cells possess advantageous features of cytotoxic T cells and natural killer (NK) cells and hold promise for advancing immunotherapy. Dual-attribute cell types such as invariant natural killer T cells, induced T-to-NK cells, and cytokine-induced killer cells have demonstrated efficacy and safety in preclinical and clinical studies. However, their limited availability hinders their widespread application. Human pluripotent stem cells (hPSCs) offer an ideal source. Here, we generate dual-attribute induced T-NK (iTNK) cells from hPSCs, expressing markers of both cytotoxic T and NK cells. Single-cell RNA and T cell receptor (TCR) sequencing analyses reveal that iTNK cells expressed signature genes associated with both NK and T cells and displayed a diverse TCR repertoire. iTNK cells release cytotoxic mediators, exert cytotoxicity against diverse tumor cell lines, and inhibit tumor growth in vivo. By harnessing adaptive and innate immune responses, hPSC-derived iTNK cells offer promising strategies for cancer immunotherapy.

Generation and assessment of cytokine-induced killer cells for the treatment of colorectal cancer liver metastases

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. Cytokine-induced killer (CIK) cells are an adoptive immunotherapy reported to have strong anti-tumour activity across a range of cancers. They are a heterogeneous mix of lymphoid cells generated by culturing human peripheral blood mononuclear cells with cytokines and monoclonal antibodies in vitro. In this study, we investigated the yield and function of CIK cells generated from patients with CRC liver metastases. We first showed that CIK cells generated in serum free medium X-VIVO 15 were comparable to those from RPMI medium with 10% FBS in terms of the number and percentages of the main subsets of cells in the CIK culture, and the intracellular levels of granzyme B and perforin, and the pro-inflammatory cytokines IL-2, IFN-γ and TNF-α. The CIK cells were cytotoxic to CRC cell lines grown in 2D cultures or as spheroids, and against autologous patient-derived tumour organoids. Donor attributes such as age, sex, or prior chemotherapy exposure had no significant impact on CIK cell numbers or function. These results suggest that functional CIK cells can be generated from patients with CRC liver metastatic disease, and support further investigations into the therapeutic application of autologous CIK cells in the management of patients with CRC liver metastases.

How can Cytokine-induced killer cells overcome CAR-T cell limits

The successful treatment of patients affected by B-cell malignancies with Chimeric Antigen Receptor (CAR)-T cells represented a breakthrough in the field of adoptive cell therapy (ACT). However, CAR-T therapy is not an option for every patient, and several needs remain unmet. In particular, the production of CAR-T cells is expensive, labor-intensive and logistically challenging; additionally, the toxicities deriving from CAR-T cells infusion, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), have been documented extensively. Alternative cellular therapy products such as Cytokine-induced killer (CIK) cells have the potential to overcome some of these obstacles. CIK cells are a heterogeneous population of polyclonal CD3+CD56+ T cells with phenotypic and functional properties of NK cells. CIK cell cytotoxicity is exerted in a major histocompatibility complex (MHC)-unrestricted manner through the engagement of natural killer group 2 member D (NKG2D) molecules, against a wide range of hematological and solid tumors without the need for prior antigen exposure or priming. The foremost potential of CIK cells lies in the very limited ability to induce graft-versus-host disease (GvHD) reactions in the allogeneic setting. CIK cells are produced with a simple and extremely efficient expansion protocol, which leads to a massive expansion of effector cells and requires a lower financial commitment compared to CAR-T cells. Indeed, CAR-T manufacturing involves the engineering with expensive GMP-grade viral vectors in centralized manufacturing facilities, whereas CIK cell production is successfully performed in local academic GMP facilities, and CIK cell treatment is now licensed in many countries. Moreover, the toxicities observed for CAR-T cells are not present in CIK cell-treated patients, thus further reducing the costs associated with hospitalization and post-infusion monitoring of patients, and ultimately encouraging the delivery of cell therapies in the outpatient setting. This review aims to give an overview of the limitations of CAR-T cell therapy and outline how the use of CIK cells could overcome such drawbacks thanks to their unique features. We highlight the undeniable advantages of using CIK cells as a therapeutic product, underlying the opportunity for further research on the topic.

PD-L1/PD-1 blockage enhanced the cytotoxicity of natural killer cell on the non-small cell lung cancer (NSCLC) by granzyme B secretion

OBJECTIVE

To explore the role of PD-L1/PD-1 blockage in the cytotoxicity of natural killer cell in NSCLC.

METHODS

Two NSCLC cell lines, Calu-1 and H460, were tested for susceptibility to the cytolytic activity of freshly isolated healthy donor NK cells by a non-radioactive cellular cytotoxicity assay kit. Western blot analysis, FACS, ELISA and antibody blockage experiments were conducted to determine the mechanisms. NK cells isolated from NSCLC patients were also collected for functional assays.

RESULTS

Calu-1 and H460 cells were lysed by NK cells in a dose-dependent manner. H460 cells showed less susceptibility to NK cell-mediated lysis than Calu-1 cells at all ratios. The expression of PD-L1 on H460 cells was higher than that on Calu-1 cells, as determined by FACS and western blot analysis. The specific lysis of H460 cells by NK cells was enhanced when the PD-L1/PD-1 interaction was blocked by anti-PD-L1 antibody. This finding was also demonstrated in NK cells isolated from NSCLC patients.

CONCLUSIONS

The present study revealed that PD-L1/PD-1 blockage enhanced the cytotoxicity of natural killer cells in NSCLC via granzyme B secretion. This study will greatly facilitate the precise treatment of lung cancer through determination of PD-L1 expression in tumors.

Cytokine-Induced Killer Cell Immunotherapy Combined With Gemcitabine Reduces Systemic Metastasis in Pancreatic Cancer: An Analysis Using Preclinical Adjuvant Therapy-Mimicking Pancreatic Cancer Xenograft Model

OBJECTIVES

To evaluate the efficacy and safety of cytokine-induced killer (CIK) cell therapy in pancreatic cancer.

METHODS

An orthotopic murine model of pancreatic cancer and adjuvant therapy-mimicking xenograft murine model that underwent splenectomy was created. Eighty mice were randomized into four groups: the control, gemcitabine alone, CIK alone, and CIK with gemcitabine groups. The tumor growth was monitored using bioluminescence imaging once weekly.

RESULTS

In the orthotopic murine model, the treatment groups showed a significantly longer survival than the control group (median: not reached vs 125.0 days; 95% confidence interval, 119.87-130.13; P = 0.04); however, the overall survival did not differ significantly among the treatment groups (P = 0.779). The metastatic recurrence rate and overall survival were also not significantly different among the groups in the adjuvant therapy-mimicking xenograft murine model (P = 0.497). However, the CIK and gemcitabine combination suppressed the metastatic recurrence effectively, with recurrence-free survival being significantly longer in the CIK with gemcitabine group than in the control group (median, 54 days; 95% confidence interval, 25.00-102.00; P = 0.013).

CONCLUSIONS

The combination of CIK and gemcitabine suppressed systemic metastatic recurrence, with promising efficacy and good tolerability in an adjuvant setting of pancreatic cancer.

Immunotherapy and Hepatocellular Cancer: Where Are We Now?

Immunotherapy has demonstrated its effectiveness in many cancers. In hepatocellular carcinoma (HCC), promising results shown in the first phase II studies evaluating anti-PD-1 or anti-PD-L1 monotherapies resulted in their approval in the United States. Approval was not obtained in Europe; subsequent randomized studies in first- or second-line treatment did not confirm these initial results. However, first data with immunotherapy plus antiangiogenic treatments or dual immunotherapy combinations were positive. In this context, the combination of bevacizumab and atezolizumab took the lead. The IMbrave150 trial revealed an improved objective response rate (ORR), progression-free survival, and overall survival with this combination versus the previous standard, sorafenib. Subsequent results of dual immunotherapy with the anti-CTLA-4 and anti-PD-1 monotherapies tremelimumab and durvalumab (also superior to sorafenib monotherapy) confirmed the value of using a combination in first-line treatment. These significant therapeutic advances, and the increase in ORR, raise two main questions. Whereas response was very limited with previous treatments, the ORR reported with these new combinations are between 20% and 30%. This raises the question of whether immunotherapy (ICI single agent, combination of ICI with antiangiogenic agent or other antitumoral treatment) can be used in patients beyond those in BCLC group C, the traditional candidate group for systemic therapy. We have thus seen an increasing number of patients previously treated with trans-arterial chemoembolization (BCLC group B) receiving these new treatments, and we develop the results of several studies combining loco-regional therapies and immunotherapy-based systemic treatments. The other major question is that of how and when to use these medical treatments as "adjuvants" to interventional radiology or surgery; the results of several works are discussed for this purpose. In this review, we cover all of these points in a fairly comprehensive manner.

NK and cells with NK-like activities in cancer immunotherapy-clinical perspectives

Natural killer (NK) cells are lymphoid cells of innate immunity that take important roles in immune surveillance. NK cells are considered as a bridge between innate and adaptive immunity, and their infiltration into tumor area is related positively with prolonged patient survival. They are defined as CD16⁺ CD56⁺ CD3^- cells in clinic. NK cells promote cytolytic effects on target cells and induce their apoptosis. Loss of NK cell cytotoxic activity and reduction in the number of activating receptors are the current issues for application of such cells in cellular immunotherapy, which resulted in the diminished long-term effects. The focus of this review is to discuss about the activity of NK cells and cells with NK-like activity including natural killer T (NKT), cytokine-induced killer (CIK) and lymphokine-activated killer (LAK) cells in immunotherapy of human solid cancers.

Cytokine-induced killer cells mediated pathways in the treatment of colorectal cancer

Cytokine-induced killer (CIK) cell therapy is a type of adoptive immunotherapy that due to its high proliferation rate and anti-tumor characteristics, is being investigated to treat various solid tumors. Since advanced colorectal cancer (CRC) has high mortality and poor survival rates, and the efficacy of chemotherapy and radiotherapy is limited in treatment, the application of CIK cell therapy in CRC has been evaluated in numerous studies. This review aims to summarize the clinical studies that investigated the safety and clinical efficacy of CIK cell therapy in CRC. Therefore, 1,969 enrolled CRC patients in the clinical trials, of which 842 patients received CIK cells in combination with chemotherapy with or without dendritic cell (DC) infusions, were included in the present review. Furthermore, the signaling pathways involved in CIK cell therapy and novel methods for improving migration abilities are discussed.

CCL17 and CCL22 induce CCR4 receptor expression and promote cytokine-induced killer cells migration

Recently, cytokine-induced killer (CIK) cells have been shown to possess effective cytotoxic activity against some tumor cells both in vitro and in clinical research. Furthermore, dendritic cell-activated CIK (DC-CIK) cells display significantly increased antitumor activity compared to unstimulated CIK cells. Study findings indicate DC cells can secrete chemokine C-C motif ligand 17 (CCL17) and chemokine C-C motif ligand 22 (CCL22) with a common receptor molecule, C-C chemokine receptor type-4(CCR4). CCL17 and CCL22 levels were measured by ELISA from CIK cell culture supernatants and the expression of CCR4 on CIK and DC-CIK cells was analyzed by flow cytometry. Through Migration and Killing assays, further analyzed the effects of the altered expression levels of CCR4 on the chemotactic ability and the tumor-killing efficiency of CIK cells. We found markedly increased CCL17 and CCL22 in supernatants of DC-CIK co-cultures. Similarly, the expression of CCR4 was also increased on CIK cells in these co-cultures. Further, the stimulation of CCL17 and CCL22 increased expression of the CCR4 and enhanced the migratory capacity and antitumor efficacy of CIK cells. Simultaneously, similar effects had achieved by transfecting the CCR4 gene into CIK cells. DC cells may promote the expression of CCR4 on CIK cells by secreting CCL17 and CCL22, thereby promoting infiltration of DC-CIK cells into the tumor microenvironment, and exerting stronger antitumor activity than CIK cells.

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.

Analysis of the expression, function, prognosis and co-expression genes of DDX20 in gastric cancer

DDX20 (DEAD-box polypeptide 20) is implicated in many cellular processes involving alteration of RNA secondary structure. The role of DDX20 in gastric cancer is still unknown. In the research, the expression of DDX20 and the functional roles of DDX20 in gastric cancer were detected. The increased DDX20 expression in gastric cancer tissue compared with normal gastric tissue was observed. Functional experiments indicated that DDX20 promoted gastric cancer MGC-803 and AGS cells growth, migration, and invasion in vitro. Surprisingly, survival analysis showed that high expression of DDX20 is a favorable prognostic factor for patients with gastric cancer. In addition, enrichment analysis revealed that there is a positive correlation between DDX20 expression and T cell activation in gastric cancer. but not in normal gastric tissues. Furthermore, we found that DDX20 expression level has significant positive correlations with activated CD8 + T cells and activated CD4 + T cells in gastric cancer. Therefore, we hypothesize that the prognostic role of DDX20 in gastric cancer patients may be due to patients with high DDX20 expression contained better immune activation. Taken together, these findings suggest that DDX20 can promote the progression of gastric cancer in vitro and its prognostic value in gastric cancer may be related to many factors, including immune activation.

Novel Immunotherapeutic Approach in Gastric Cancer

Gastric cancer (GC) is suitable for immunotherapy because 80% of it display microsatellite and chromosomal instability, some mutations and DNA hypermethylation. Therefore, GC is more immunogenic. The immunotherapy with monoclonal antibodies, adoptive cell therapy and checkpoint inhibition are discussed. The commonly used monoclonal antibodies are Trastuzumab targeting HER2 and Bevacizumab suppressing VEGF and tumor angiogenesis. Treatment with tumor-specific T cells is called adoptive cell therapy. There is experience with the application of tumor infiltrating lymphocytes (TILs), cytotoxic T lymphocytes (CTLs) and cytokine-induced killer cells (CIK). This review discusses the therapy with innate immune cells with anti-tumor activity such as dendritic cells and NK cells. The checkpoint inhibition was also reviewed. In conclusion, it could be stated that the immunotherapy of GC has the potential to provide a more favorable outcome to patients with GC, but it also have some limitations which need to be considered.

High Expression of Cannabinoid Receptor 2 on Cytokine-Induced Killer Cells and Multiple Myeloma Cells

Multiple myeloma (MM) is characterized by aberrant bone marrow plasma cell (PC) proliferation and is one of the most common hematological malignancies. The potential effect of cannabinoids on the immune system and hematological malignancies has been poorly characterized. Cannabidiol (CBD) may be used to treat various diseases. CBD is known to exert immunomodulatory effects through the activation of cannabinoid receptor 2 (CB2), which is expressed in high levels in the hematopoietic system. Cytokine-induced killer (CIK) cells are a heterogeneous population of polyclonal T lymphocytes obtained via ex vivo sequential incubation of peripheral blood mononuclear cells (PBMCs) with interferon-γ (IFN-γ), anti CD3 monoclonal antibody, and IL-2. They are characterized by the expression of CD3+ and CD56+, which are surface markers common to T lymphocytes and natural killer (NK) cells. CIK cells are mainly used in hematological patients who suffer relapse after allogeneic transplantation. Here, we investigated their antitumor effect in combination with pure cannabidiol in KMS-12 MM cells by lactate dehydrogenase LDH cytotoxicity assay, CCK-8 assay, and flow cytometry analysis. The surface and intracellular CB2 expressions on CIK cells and on KMS-12 and U-266 MM cell lines were also detected by flow cytometry. Our findings confirm that the CB2 receptor is highly expressed on CIK cells as well as on MM cells. CBD was able to decrease the viability of tumor cells and can have a protective role for CIK cells. It also inhibits the cytotoxic activity of CIKs against MM at high concentrations, so in view of a clinical perspective, it has to be considered that the lower concentration of 1 µM can be used in combination with CIK cells. Further studies will be required to address the mechanism of CBD modulation of CIK cells in more detail.

Preclinical immunotherapy with Cytokine-Induced Killer lymphocytes against epithelial ovarian cancer

Despite improvements in surgery and medical treatments, epithelial ovarian cancer (EOC) remains the most lethal gynaecological malignancy. Aim of this study is to investigate the preclinical immunotherapy activity of cytokine-induced killer lymphocytes (CIK) against epithelial ovarian cancers, focusing on platinum-resistant settings. We generated CIK ex vivo starting from human peripheral blood samples (PBMCs) collected from EOC patients. Their antitumor activity was tested in vitro and in vivo against platinum-resistant patient-derived ovarian cancer cells (pdOVCs) and a Patient Derived Xenograft (PDX), respectively. CIK were efficiently generated (48 fold median ex vivo expansion) from EOC patients; pdOVCs lines (n = 9) were successfully generated from metastatic ascites; the expression of CIK target molecules by pdOVC confirmed pre and post treatment in vitro with carboplatin. The results indicate that patient-derived CIK effectively killed autologous pdOVCs in vitro. Such intense activity was maintained against a subset of pdOVC that survived in vitro treatment with carboplatin. Moreover, CIK antitumor activity and tumor homing was confirmed in vivo within an EOC PDX model. Our preliminary data suggest that CIK are active in platinum resistant ovarian cancer models and should be therefore further investigated as a new therapeutic option in this extremely challenging setting.

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.

Efficacy of cytokine-induced killer cell-based immunotherapy for hepatocellular carcinoma

In attempts to delay tumor progression after surgery or minimally invasive local treatments, multidisciplinary strategies have been broadly studied in patients with hepatocellular carcinoma (HCC). The objective of this present study was to evaluate the efficacy of autologous transplantations of cytokine-induced killer (CIK) cells as an adjuvant therapy for patients with HCC. A total of 264 patients with HCC were enrolled in this retrospective study. Of these patients, 165 received either CIK cell therapy alone or as adjuvant therapy to surgery, transcatheter arterial chemoembolization (TACE), or TACE-based comprehensive treatments (CT). The remaining 99 patients received only surgery or TACE. Kaplan-Meier analysis and the Chi-squared test were used to analyze the overall survival (OS), progression-free survival (PFS), and clinical characteristics of the patients in the different treatment subgroups. Kaplan-Meier analysis suggested that patients in the Surgery+CIK group had a significantly improved OS compared with those in the other three groups (P < 0.001). Furthermore, patients who developed a fever after the CIK cell treatments manifested a likely better OS (P = 0.028). Subgroup analysis indicated that patients in the Surgery+CIK group likely had an improved PFS but a similar OS compared with the patients in the Surgery-alone group (P = 0.055 for PFS, and P = 0.746 for OS). Further subgroup analysis showed that the OS in both the TACE+CIK and CT+CIK groups was prolonged significantly compared with that in the TACE-alone group (P = 0.015 and P = 0.018, respectively). However, similar OS was observed between the TACE+CIK and CT+CIK groups (P = 0.686). Autologous transplantation of CIK cells as an adjuvant therapy was associated with better survival for patients with HCC, especially for those who had also undergone TACE. A fever reaction might be a potential event for assessing the curative effect of the CIK treatment.

Utilizing ethacrynic acid and ciclopirox olamine in liver cancer

Once aberrantly activated, the Wnt/β-catenin pathway may result in uncontrolled proliferation and eventually cancer. Efforts to counter and inhibit this pathway are mainly directed against β-catenin, as it serves a role on the cytoplasm and the nucleus. In addition, specially-generated lymphocytes are recruited for the purpose of treating liver cancer. Peripheral blood mononuclear lymphocytes are expanded by the timely addition of interferon γ, interleukin (IL)-1β, IL-2 and anti-cluster of differentiation 3 antibody. The resulting cells are called cytokine-induced killer (CIK) cells. The present study utilised these cells and combine them with drugs inhibiting the Wnt pathway in order to examine whether this resulted in an improvement in the killing ability of CIK cells against liver cancer cells. Drugs including ethacrynic acid (EA) and ciclopirox olamine (CPX) were determined to be suitable candidates, as determined by previous studies. Drugs were administered on their own and combined with CIK cells and then a cell viability assay was performed. These results suggest that EA-treated cells demonstrated apoptosis and were significantly affected compared with untreated cells. Unlike EA, CPX killed normal and cancerous cells even at low concentrations. Subsequent to combining EA with CIK cells, the potency of killing was increased and a greater number of cells died, which proves a synergistic action. In summary, EA may be used as an anti-hepatocellular carcinoma drug, while CPX possesses a high toxicity to cancerous as well as to normal cells. It was proposed that EA should be integrated into present therapeutic methods for cancer.

Chemotherapy plus dendritic cells co-cultured with cytokine-induced killer cells versus chemotherapy alone to treat advanced non-small-cell lung cancer: A meta-analysis

This study was aimed to investigate the efficacy and safety of the combination treatment of dendritic cells co-cultured with cytokine-induced killer cells and chemotherapy for patients with advanced non-small-cell lung cancer (NSCLC). Literatures were searched from the Cochrane Library Central, PubMed, Web of Science and EMBASE. The primary endpoint of interest was overall survival (OS), and secondary endpoints were disease control rate (DCR) and progression free survival (PFS). Finally 7 trials published between January 2005 and March 2016 met inclusion criteria and totally 610 patients were enrolled. The combination group showed advance in DCR (RR = 1.31, 95% CI = 1.13-1.52, p = 0.0004), 1-year OS (RR = 1.18, 95% CI = 1.05-1.33, p = 0.007), and 2-year OS (RR = 1.37, 95% CI = 1.10-1.70, p = 0.005), with statistical significance. The proportions of CD3⁺ T cells (p = 0.002), NK cells (p = 0.02) and NKT cells (p = 0.001) were significantly higher in the peripheral blood of combination group, compared with those of the control group. Moreover, adverse reactions were obviously decreased in the combination group. However, no significant difference was identified in ORR and PFS between two groups (p > 0.05). In conclusion, the combination therapy was safe and applicable for patients with advanced NSCLC.

All-trans retinoic acid enhances cytotoxicity of CIK cells against human lung adenocarcinoma by upregulating MICA and IL-2 secretion

To determine the growth inhibition capability of all-trans retinoic acid (ATRA) with cytokine-induced killer cells (CIKs), we evaluated their effects, alone and in combination, on human lung carcinoma A549 cells. CIKs treated with ATRA significantly inhibited cell growth. Additionally, CIK with ATRA synergistically inhibited migration and invasiveness, colony formation of A549 and NCI-H520 cells. Furthermore, analysis of apoptosis markers Bcl-2, Bax, Survivin and cleaved Caspase-3 showed that Bcl-2 and Survivin mRNA levels significantly decreased, and that Bax mRNA significantly increased, in the CIK + ATRA-treated cells, with corresponding effects on their respective proteins. The involved mechanisms may be associated with upregulated expression of MHC class I-Related Chain (MICA) and interleukin (IL)-2. These results suggest that administration of combined CIK and ATRA is a potentially novel treatment for lung carcinoma.

The progress and current status of immunotherapy in acute myeloid leukemia

Recently, there has been remarkable progress in basic and preclinical studies of acute myeloid leukemia (AML). The improved outcomes of AML can largely be attributed to advances in supportive care and hematopoietic cell transplantation as opposed to conventional chemotherapy. However, as the 5-year survival rate remains low due to a high incidence of relapse, novel and effective treatments are urgently needed. Increasing attention is focusing on identifying suitable immunotherapeutic strategies for AML. Here, we describe the immunological features, mechanisms of immune escape, and recent progress in immunotherapy for AML. Problems encountered in the clinic will also be discussed. Although current outcomes may be limited, ongoing preclinical or clinical efforts are aimed at improving immunotherapy modalities and designing novel therapies, such as vaccines, monoclonal antibody therapy, chimeric antibody receptor-engineered T cells (CAR-T), TCR-engineered T cells (TCR-T), and checkpoint inhibitors, which may provide promising and effective therapies with higher specificity and efficacy for AML.

Synergistic effect of cytokine-induced killer cell with valproate inhibits growth of hepatocellular carcinoma cell in a mouse model

OBJECTIVE

Long-term prognosis of hepatocellular carcinoma (HCC) remains poor owing to the lack of treatment options for advanced HCC. Cytokine-induced killer (CIK) cells are ex vivo expanded T lymphocytes expressing both NK- and T-cell markers. CIK cell therapy alone is insufficient for treating advanced HCC. Thus, this study aimed to determine whether treatment with CIK cells combined with valproic acid (VPA) could provide a synergistic effect to inhibit tumor growth in a mouse model of HCC.

METHODS

Upregulation of natural killer group 2D (NKG2D) ligands (retinoic acid early inducible 1 [RAE-1], mouse; major histocompatibility complex class I polypeptide-related sequence A [MIC-A], human) were evaluated by FACS. VPA concentrations that did not reduce tumor volume were calculated to avoid VPA cytotoxicity in a C3H mouse model of HCC. CIK cells were generated from mouse splenocytes using interferon gamma, a CD3 monoclonal antibody, and interleukin 2. The potential synergistic effect of CIK cells combined with VPA was evaluated in the mouse model and tissue pathology was investigated.

RESULTS

After 40 h of incubation with VPA, RAE-1 and MIC-A expression were increased in 4 HCC cell lines compared with that in control (2.3-fold in MH-134, 2.4-fold in Huh-7, 3.7-fold in SNU-761, and 6.5-fold in SNU-475). The maximal in vivo VPA dosage that showed no significant cytotoxicity compared with control was 10 mg/kg/day. CIK cells were well generated from C3H mouse splenocytes. After 7 d of treatment with CIK cells plus VPA, a synergistic effect was observed on relative tumor volume in the mouse model of HCC. While the relative tumor volume in untreated control mice increased to 11.25, that in the combination treatment group increased to only 5.20 (P = 0.047).

CONCLUSIONS

The VPA-induced increase in NKG2D ligands expression significantly enhanced the effects of CIK cell therapy in a mouse model of HCC.

Generation and characterization of ErbB2-CAR-engineered cytokine-induced killer cells for the treatment of high-risk soft tissue sarcoma in children

Pediatric patients with recurrent, refractory or advanced soft tissue sarcoma (STS) who are simultaneously showing signs of cumulative treatment toxicity are in need of novel therapies. In this preclinical analysis, we identified ErbB2 as a targetable antigen on STS cells and used cytokine-induced killer (CIK) cells transduced with the lentiviral 2^nd-generation chimeric antigen receptor (CAR) vector pS-5.28.z-IEW to target ErbB2-positive tumors. Solely CIK cell subsets with the CD3⁺ T cell phenotype showed up to 85% cell surface expression of the respective CAR. A comparison of wildtype (WT), mock-vector and ErbB2-CAR-CIK cells showed, that engineered cells exhibited diminished in vitro expansion, retained WT CIK cell phenotype with higher percentages of differentiated effector memory/effector cells. Activating natural killer (NK) cell receptor NKG2D-restricted target cell recognition and killing of WT and ErbB2-CAR-CIK cells was maintained against ErbB2-negative tumors, while ErbB2-CAR-CIK cells demonstrated significantly increased cytotoxicity against ErbB2-positive targets, including primary tumors. ErbB2-CAR- but not WT CIK cells proliferated, infiltrated and efficiently lysed tumor cell monolayers as well as 3D tumor spheroids.

Here, we demonstrate a potential cell therapeutic approach using ErbB2-CAR-CIK cells for the recognition and elimination of tumor cells expressing ErbB2, which we identified as a targetable antigen on high-risk STS cells.

Treating breast cancer with cell-based approaches: an overview

INTRODUCTION

Breast cancer is the most common malignancy in women. Despite there being considerable progress in the treatment of this disease, metastatic dissemination is still considered an incurable condition at the present time, causing 500,000 deaths worldwide every year. Although most of the research efforts have been focused on pharmacological approaches, over the last three decades, the use of bone marrow and peripheral blood-derived cell therapy approaches have been attempted and developed. Areas covered: This review will briefly address cell therapy for breast cancer, including autologous stem cell transplantations for overcoming the myelosuppressive effects of high-dose chemotherapy, allogeneic stem cell transplants and adoptive immunotherapy using bone-marrow derived T-cells. Expert opinion: The treatment of breast cancer using bone marrow or peripheral-blood derived cells has evolved from a supportive care approach to allow dose escalation of conventional chemotherapy to a therapeutic strategy aimed at eliciting immune cell mediated anticancer immunity. This latter principle has led to the development of adoptive immunotherapies, either with 'natural' or genetically engineered effectors, which are being intensively investigated for their great potential against several solid tumors, including breast cancer.

Oncolytic measles virus enhances antitumour responses of adoptive CD8+NKG2D+ cells in hepatocellular carcinoma treatment

There is an urgent need for novel effective treatment for hepatocellular carcinoma (HCC). Oncolytic viruses (OVs) not only directly lyse malignant cells, but also induce potent antitumour immune responses. The potency and precise mechanisms of antitumour immune activation by attenuated measles virus remain unclear. In this study, we investigated the potency of the measles virus vaccine strain Edmonston (MV-Edm) in improving adoptive CD8⁺NKG2D⁺ cells for HCC treatment. We show that MV-Edm-infected HCC enhanced the antitumour activity of CD8⁺NKG2D⁺ cells, mediated by at least three distinct mechanisms. First, MV-Edm infection compelled HCC cells to express the specific NKG2D ligands MICA/B, which may contribute to the activation of CD8⁺NKG2D⁺ cells. Second, MV-Edm-infected HCC cells stimulated CD8⁺NKG2D⁺ cells to express high level of FasL resulting in enhanced induction of apoptosis. Third, intratumoural administration of MV-Edm enhanced infiltration of intravenously injected CD8⁺NKG2D⁺ cells. Moreover, we found that MV-Edm and adoptive CD8⁺NKG2D⁺ cells, either administered alone or combined, upregulated the immune suppressive enzyme indoleamine 2,3-dioxygenase 1 (IDO1) in HCC. Elimination of IDO1 by fludarabine enhanced antitumour responses. Taken together, our data provide a novel and clinically relevant strategy for treatment of HCC.

Cytokine-Induced Killer Cells As Pharmacological Tools for Cancer Immunotherapy

Cytokine-induced killer (CIK) cells are a heterogeneous population of effector CD3⁺CD56⁺ natural killer T cells, which can be easily expanded in vitro from peripheral blood mononuclear cells. CIK cells work as pharmacological tools for cancer immunotherapy as they exhibit MHC-unrestricted, safe, and effective antitumor activity. Much effort has been made to improve CIK cells cytotoxicity and treatments of CIK cells combined with other antitumor therapies are applied. This review summarizes some strategies, including the combination of CIK with additional cytokines, dendritic cells, check point inhibitors, antibodies, chemotherapeutic agents, nanomedicines, and engineering CIK cells with a chimeric antigen receptor. Furthermore, we briefly sum up the clinical trials on CIK cells and compare the effect of clinical CIK therapy with other immunotherapies. Finally, further research is needed to clarify the pharmacological mechanism of CIK and provide evidence to formulate uniform culturing criteria for CIK expansion.

Novel therapeutic targets on the horizon for lung cancer

Lung cancer is a leading cause of cancer-related mortality worldwide, and is classically divided into two major histological subtypes: non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Although NSCLC and SCLC are considered distinct entities with different genomic landscapes, emerging evidence highlights a convergence in therapeutically relevant targets for both histologies. In adenocarcinomas with defined alterations such as EGFR mutations and ALK translocations, targeted therapies are now first-line standard of care. By contrast, many experimental and targeted agents remain largely unsuccessful for SCLC. Intense preclinical research and clinical trials are underway to exploit unique traits of lung cancer, such as oncogene dependency, DNA damage response, angiogenesis, and cellular plasticity arising from presence of cancer stem cell lineages. In addition, the promising clinical activity observed in NSCLC in response to immune checkpoint blockade has spurred great interest in the field of immunooncology, with the scope to develop a diverse repertoire of synergistic and personalised immunotherapeutics. In this Review, we discuss novel therapeutic agents for lung cancer that are in early-stage development, and how prospective clinical trials and drug development may be shaped by a deeper understanding of this heterogeneous disease.

Cytokines for the induction of antitumor effectors: The paradigm of Cytokine-Induced Killer (CIK) cells

Cytokine-Induced killer (CIK) cells are raising growing interest in cellular antitumor therapy, as they can be easily expanded with a straightforward and inexpensive protocol, and are safe requiring only GMP-grade cytokines to obtain very high amounts of cytotoxic cells. CIK cells do not need antigen-specific stimuli to be activated and proliferate, as they recognize and destroy tumor cells in an HLA-independent fashion through the engagement of NKG2D. In several preclinical studies and clinical trials, CIK cells showed a reduced alloreactivity compared to conventional T cells, even when challenged across HLA-barriers; only in a few patients, a mild GVHD occurred after treatment with allogeneic CIK cells. Additionally, their antitumor activity can be redirected and further improved with chimeric antigen receptors, clinical-grade monoclonal antibodies or immune checkpoint inhibitors. The evidence obtained from a growing body of literature support CIK cells as a very promising cell population for adoptive immunotherapy. In this review, all these aspects will be addressed with a particular emphasis on the role of the cytokines involved in CIK cell generation, expansion and functionalization.

Cell-based immunotherapy with cytokine-induced killer (CIK) cells: From preparation and testing to clinical application

Cell-based immunotherapy holds promise in the quest for the treatment of cancer, having potential synergy with surgery, chemotherapy and radiotherapy. As a novel approach for adoptive cell-based immunotherapy, cytokine-induced killer (CIK) cells have moved from the 'bench to bedside'. CIK cells are a heterogeneous subset of ex-vitro expanded, polyclonal T-effector cells with both natural killer (NK) and T-cell properties, which present potent non-major histocompatibility complex-restricted cytotoxicity against a variety of tumor target cells. Initial clinical studies on CIK cell therapy have provided encouraging results and revealed synergistic antitumor effects when combined with standard therapeutic procedures. At the same time, issues such as inadequate quality control and quantity of CIK cells as well as exaggerated propaganda were continuously emerging. Thus, the Ministry of Health in China stopped CIK cell therapy in May 2016, which was a major setback for the innovation of CIK cell-based immunotherapy. Thus, it is very important to modify technical criteria to develop a standardized operation procedure (SOP) and standardized system for evaluating antitumor efficacy in a safe way.

Modification of cytokine-induced killer cells with folate receptor alpha (FRα)-specific chimeric antigen receptors enhances their antitumor immunity toward FRα-positive ovarian cancers

Folate receptor alpha (FRα) is aberrantly expressed in ovarian cancers but largely absent in normal tissues, and therefore represents an attractive target for immunotherapy. In recent years, modification of T cells with chimeric antigen receptor (CAR) targeting FRα has been reported to improve antitumor immunity of T cells. However, there are limited data regarding CAR-modified cytokine-induced killer (CAR-CIK) cells. In the present study, we modified CIK cells with FRα-specific CARs and investigated their antitumor immunity against ovarian cancers. We found that both non-transduced and mock CAR-transduced CIK cells showed only low antitumor activity against either FRα-positive (FRα⁺) or FRα-negative (FRα^-) targets. However, all three generations of CAR-modified CIK cells showed enhanced antitumor activity against FRα⁺ targets, but not FRα^- targets. First-generation ζ-CAR-CIK cells increased production of IFN-γ, enhanced short-term cytotoxicity against FRα⁺ ovarian cancer cells, and showed modest and short-term suppression of established tumors; while second-generation 28ζ- and third-generation 28BBζ-CAR-CIK cells showed significant proliferation, enhanced secretion of IL-2, eliminated the FRα⁺ ovarian cancer cells in long-term co-culture, and showed dramatic and long-term inhibition of tumor growth and prolonged survival of xenograft-bearing mice. It is noteworthy that the 28BBζ-CAR was more potent in the modification of CIK cells than 28ζ-CAR both in vitro and in vivo. Moreover, CAR-CIK cells showed more efficient anticancer activity compared with CAR-T cells in vitro, but less efficient than CAR-T cells in vivo. According to these results, we conclude that modification of CIK cells with FRα-specific CARs enhances their antitumor immunity to FRα⁺ ovarian cancers. The third-generation 28BB-ζ CAR containing 4-1BB co-stimulation was more efficient in modification of CIK cells than either first-generation ζ-CAR or second-generation CD28-ζ-CAR.

Cytotoxic potential of IL-15-activated cytokine-induced killer cells against human neuroblastoma cells

BACKGROUND

Neuroblastoma (NB) is the most common solid extracranial tumor in childhood. Despite advances in therapy, the prognosis is poor and optimized therapies are urgently needed. Therefore, we investigated the antitumor potential of interleukin-15 (IL-15)-activated cytokine-induced killer (CIK) cells against different NB cell lines.

PROCEDURE

CIK cells were generated from peripheral blood mononuclear cells by the stimulation with interferon-γ (IFN-γ), IL-2, OKT-3 and IL-15 over a period of 10-12 days. The cytotoxic activity against NB cells was analyzed by nonradioactive Europium release assay before and after blocking of different receptor-ligand interactions relevant in CIK cell-mediated cytotoxicity.

RESULTS

The final CIK cell products consisted in median of 83% (range: 75.9-91.9%) CD3⁺ CD56^- T cells, 14% (range: 5.2-20.7%) CD3⁺ CD56⁺ NK-like T cells and 2% (range: 0.9-4.8%) CD3^- CD56⁺ NK cells. CIK cells expanded significantly upon ex vivo stimulation with median rates of 22.3-fold for T cells, 58.3-fold for NK-like T cells and 2.5-fold for NK cells. Interestingly, CD25 surface expression increased from less than equal to 1% up to median 79.7%. Cytotoxic activity of CIK cells against NB cells was in median 34.7, 25.9 and 34.8% against the cell lines UKF-NB-3, UKF-NB-4 and SK-N-SH, respectively. In comparison with IL-2-stimulated NK cells, CIK cells showed a significantly higher cytotoxicity. Antibody-mediated blocking of the receptors NKG2D, TRAIL, FasL, DNAM-1, NKp30 and lymphocyte function-associated antigen-1 (LFA-1) significantly reduced lytic activity, indicating that diverse cytotoxic mechanisms might be involved in CIK cell-mediated NB killing.

CONCLUSIONS

Unlike the mechanism reported in other malignancies, NKG2D-mediated cytotoxicity does not constitute the major killing mechanism of CIK cells against NB.

MDSC-decreasing chemotherapy increases the efficacy of cytokine-induced killer cell immunotherapy in metastatic renal cell carcinoma and pancreatic cancer

Adoptive immunotherapy using cytokine-induced killer (CIK) cells is a promising cancer treatment, but its efficacy is restricted by various factors, including the accumulation of myeloid-derived suppressor cells (MDSCs). In this study, we determine whether chemotherapeutic drugs that reduce MDSC levels enhance the efficacy of CIK cell therapy in the treatment of solid tumors. Fifty-three patients were included in this study; 17 were diagnosed with metastatic renal cell carcinoma (MRCC), 10 with advanced pancreatic cancer (PC), and 26 with metastatic melanoma (MM). These patients were divided into two groups: CIK cell therapy alone and CIK cell therapy combined with chemotherapy. Combining CIK cell therapy and chemotherapy increased 1-year survival rates and median survival times in MRCC and PC patients, but not in MM patients. The disease control rate did not differ between treatment groups for MRCC or MM patients, but was higher in PC patients receiving combined treatment than CIK cell treatment alone. These data suggest that addition of MDSC-decreasing chemotherapy to CIK cell therapy improves survival in MRCC and PC patients.

Curative Effects of Dendritic Cells Combined with Cytokine-Induced Killer Cells in Patients with Malignant Pericardial Effusion

Background

To determine the effects of dendritic cells (DCs) and cytokine-induced killer (CIK) cells in patients with malignant pericardial effusion.

Material/Methods

All patients underwent pericardial puncture and indwelling catheter insertion. After pericardial drainage, the 16 patients in the treatment group received an infusion of 20 mL DCs and CIK cells (>1.0×10¹⁰ cells) and 500,000 U interleukin (IL)-2 for 3 successive days. The 15 control-group patients received 30 mg/m² cisplatin and 500,000 U IL-2 for 3 successive days. The treatment effects were assessed using imaging data.

Results

The total efficiency and complete remission rates were higher in the treatment group than in the control group at 4 weeks (total efficiency: 87.50% vs. 73.33%; complete remission: 62.50% vs. 46.67%) and 3 months after the treatment (total efficiency: 81.25% vs. 66.67%; complete remission: 50.00% vs. 40.00%; P<0.05 for all). In both groups, the Karnofsky scores for quality of life improved after treatment. However, the curative effects were better in the treatment group than in the control group (P<0.05). The following adverse reactions occurred: fever, 6 treatment-group patients and 3 control-group patients; chest pain, 2 treatment-group patients and 7 control-group patients; gastrointestinal reactions, 1 treatment-group patient and 6 control-group patients; and bone marrow suppression, 1 treatment-group patient and 5 control-group patients. The between-group differences in adverse reactions were significant (P<0.05).

Conclusions

The combination of DCs and CIK cells effectively treated malignant pericardial effusion, produced few side effects, and improved the patients’ quality of life.

Adjuvant immunotherapy with autologous cytokine-induced killer cells for hepatocellular carcinoma patients after curative resection, a systematic review and meta-analysis

BACKGROUND

Cytokine-induced killer cells have been used as an adjuvant treatment for hepatocellular carcinoma with curative treatment. However, the outcomes remain controversial.

AIM

We conducted this meta-analysis to assess the safety and efficacy of cytokine-induced killer cells.

METHODS

Randomized controlled trials on cytokine-induced killer cells for hepatocellular carcinoma after curative treatments were identified by electronic searches. A meta-analysis was carried out to examine disease-free survival, overall survival rate and adverse effect.

RESULTS

Six randomized controlled trials with 844 patients (85.9% with hepatitis B or C) were included. Our meta-analysis showed that cytokine-induced killer cells can not only improve the 1-year (RR=1.23, P<0.001), 2-year (RR=1.37, P<0.001) and 3-year (RR=1.35, P=0.004) disease-free survival, but also improve the 1-year (RR=1.08, P=0.001), 2-year (RR=1.14, P<0.001) and 3-year (RR=1.15, P=0.02) overall survival. However, it failed to affect the 4-year and 5-year disease-free survival and overall survival (P>0.05). At the same time, cytokine-induced killer cells treatment was proved to be a safe strategy with the comparable adverse events comparing to the control group (P=0.39).

CONCLUSIONS

This review provides the best available evidence that adjuvant cytokine-induced killer cells treatment can be safely used to improve the early disease-free survival and survival of hepatitis B or C related hepatocellular carcinoma.

Interleukin-15 enhances cytokine induced killer (CIK) cytotoxic potential against epithelial cancer cell lines via an innate pathway

CIK cells are a subset of effector lymphocytes endowed with a non-MHC restricted anti-tumor activity making them an appealing and promising cell population for adoptive immunotherapy. CIK are usually generated ex-vivo by initial priming with Interferon-γ (IFN-γ) and monoclonal antibody against CD3 (anti-CD3), followed by culture in medium containing Interleukin-2 (IL-2). Interleukin-15 (IL-15) shares with IL-2 similar biological functions and recently it has been reported to induce CIK with increased anti-leukemic potential. The aim of the study was to compare the killing efficacy of CIK generated by IL-2 alone or IL-2 and IL-15 toward tumor targets of different origins, leukemic cells and malignant cells from epithelial solid tumors. CIK bulk cultures were examined for cell proliferation, surface phenotype and cytotoxic potential against tumor cell lines K562, HL60, HeLa and MCF-7. The results showed that IL-15 is able to induce a selective expansion of CIK cells, but it is less effective in sustaining CIK cell proliferation compared to IL-2. Conversely, our data confirm and reinforce the feature of IL-15 to induce CIK cells with a potent cytotoxic activity mostly against tumor cells from epithelial solid malignancies via NKG2D-mediated mechanism.

Cytokine-induced killer cells efficiently kill stem-like cancer cells of nasopharyngeal carcinoma via the NKG2D-ligands recognition

Cancer stem cells (CSCs) are considered to be the root cause for cancer treatment failure. Thus, there remains an urgent need for more potent and safer therapies against CSCs for curing cancer. In this study, the antitumor activity of cytokine-induced killer (CIK) cells against putative CSCs of nasopharyngeal carcinoma (NPC) was fully evaluated in vitro and in vivo. To visualize putative CSCs in vitro by fluorescence imaging, and image and quantify putative CSCs in tumor xenograft-bearing mice by in vivo bioluminescence imaging, NPC cells were engineered with CSC detector vector encoding GFP and luciferase (Luc) under control of Nanog promoter. Our study reported in vitro intense tumor-killing activity of CIK cells against putative CSCs of NPC, as revealed by percentage analysis of side population cells, tumorsphere formation assay and Nanog-promoter-GFP-Luc reporter gene strategy plus time-lapse recording. Additionally, time-lapse imaging firstly illustrated that GFP-labeled or PKH26-labeled putative CSCs or tumorspheres were usually attacked simultaneously by many CIK cells and finally killed by CIK cells, suggesting the necessity of achieving sufficient effector-to-target ratios. We firstly confirmed that NKG2D blockade by anti-NKG2D antibody significantly but partially abrogated CIK cell-mediated cytolysis against putative CSCs. More importantly, intravenous infusion of CIK cells significantly delayed tumor growth in NOD/SCID mice, accompanied by a remarkable reduction in putative CSC number monitored by whole-body bioluminescence imaging. Taken together, our findings suggest that CIK cells demonstrate the intense tumor-killing activity against putative CSCs of NPC, at least in part, by NKG2D-ligands recognition. These results indicate that CIK cell-based therapeutic strategy against CSCs presents a promising and safe approach for cancer treatment.

Harnessing the immune system to improve cancer therapy

Cancer immunotherapy uses the immune system and its components to mount an anti-tumor response. During the last decade, it has evolved from a promising therapy option to a robust clinical reality. Many immunotherapeutic modalities are already approved by the Food and Drug Administration (FDA) for treating cancer patients and many others are in the pipeline for approval as standalone or combinatorial therapeutic interventions, several also combined with standard treatments in clinical studies. The two main axes of cancer immunotherapeutics refer to passive and active treatments. Prominent examples of passive immunotherapy include administration of monoclonal antibodies and cytokines and adoptive cell transfer of ex vivo "educated" immune cells. Active immunotherapy refers, among others, to anti-cancer vaccines [peptide, dendritic cell (DC)-based and allogeneic whole cell vaccines], immune checkpoint inhibitors and oncolytic viruses, whereas new approaches that can further enhance anti-cancer immune responses are also widely explored. Herein, we present the most popular cancer immunotherapy approaches and discuss their clinical relevance referring to data acquired from clinical trials. To date, clinical experience and efficacy suggest that combining more than one immunotherapy interventions, in conjunction with other treatment options like chemotherapy, radiotherapy and targeted or epigenetic therapy, should guide the way to cancer cure.

Effectiveness and safety of chemotherapy combined with cytokine-induced killer cell /dendritic cell-cytokine-induced killer cell therapy for treatment of gastric cancer in China: A systematic review and meta-analysis

BACKGROUND

Currently, cytokine-induced killer cells (CIK)/dendritic cell (DC)-CIK-mediated immunotherapy is widely used to treat gastric cancer. However, limited information regarding clinical trials on CIK/DC-CIK therapy is available. Therefore, systemic evaluation of the efficacy and safety of the combination therapy is necessary.

METHODS

A meta-analysis involving 1735 patients with gastric cancer was conducted. Before analysis, the study quality and heterogeneity were evaluated. The effects of chemotherapy combined with CIK/DC-CIK on gastric cancer were compared with the effects observed when chemotherapy alone was used. Pooled analysis was performed using RevMan version 5.2 from random or fixed-effect models.

RESULTS

Seventeen trials were included. First, the analysis showed that the combination therapy significantly increased the overall survival rate and disease-free survival rate compared with those in patients treated using chemotherapy alone. The overall response rate (P = 0.002), disease control rate (P = 0.0007), and quality of life improved rate (P = 0.0008) were significantly improved in patients who received combined treatment than in patients who received chemotherapy alone. Second, the percentage of lymphocyte subsets (CD3(+), CD4(+) and CD3(-)CD56(+), CD3(+)CD56(+); P <0.01) and the levels of interleukin-12 and interferon-γ, which reflect immune function, were significantly increased (P <0.05) after the CIK/DC-CIK therapy. Further, carbohydrate antigen tumor markers were significantly reduced compared with the pre-therapy levels. Immunotherapy with CIK/DC-CIK obviously alleviated the adverse events caused by chemotherapy.

CONCLUSION

The combination of CIK/DC-CIK therapy and chemotherapy was superior in prolonging the survival time, enhancing immune function and alleviating the adverse events caused by chemotherapy.

Efficacy of adoptive cellular therapy in patients with gastric cancer: a meta-analysis

Aim: To systemically evaluate the efficacy and safety of adoptive cellular therapy for the treatment of gastric cancer (GC). Materials & methods: We performed a systemic review and meta-analysis of nine eligible trials with GC and evaluated the effect of adoptive cellular therapy on the overall survival (OS) rate, T-cell subsets and adverse events. Results: Overall, 829 patients were involved in the analysis. Adoptive cellular therapy significantly improved the OS rate compared with the control group. Meanwhile, we observed greatly increased percentages of CD3+, CD4+ and CD4+/CD8+ in cellular therapy groups. Conclusion: Adoptive cellular therapy combined with adjuvant therapy resulted in significantly better OS rates, progression-free survival and T-lymphocyte responses in patients with GC.

Retargeting cytokine-induced killer cell activity by CD16 engagement with clinical-grade antibodies

Cytokine-induced Killer (CIK) cells are a heterogeneous population of ex vivo expanded T lymphocytes capable of MHC-unrestricted antitumor activity, which share phenotypic and functional features with both NK and T cells. Preclinical data and initial clinical studies demonstrated their high tolerability in vivo, supporting CIK cells as a promising cell population for adoptive cell immunotherapy. In this study, we report for the first time that CIK cells display a donor-dependent expression of CD16, which can be engaged by trastuzumab or cetuximab to exert a potent antibody-dependent cell-mediated cytotoxicity (ADCC) against ovarian and breast cancer cell lines, leading to an increased lytic activity in vitro, and an enhanced therapeutic efficacy in vivo. Thus, an efficient tumor antigen-specific retargeting can be achieved by a combination therapy with clinical-grade monoclonal antibodies already widely used in cancer therapy, and CIK cell populations that are easily expandable in very large numbers, inexpensive, safe and do not require genetic manipulations. Overall, these data provide a new therapeutic strategy for the treatment of Her2 and EGFR expressing tumors by adoptive cell therapy, which could find wide implementation and application, and could also be expanded to the use of additional therapeutic antibodies.

Adoptive immunotherapy against ovarian cancer

The standard front-line therapy for epithelial ovarian cancer (EOC) is combination of debulking surgery and platinum-based chemotherapy. Nevertheless, the majority of patients experience disease recurrence. Although extensive efforts to find new therapeutic options, cancer cells invariably develop drug resistance and disease progression. New therapeutic strategies are needed to improve prognosis of patients with advanced EOC.

Recently, several preclinical and clinical studies investigated feasibility and activity of adoptive immunotherapy in EOC. Our aim is to highlight prospective of adoptive immunotherapy in EOC, focusing on HLA-restricted Tumor Infiltrating Lymphocytes (TILs), and MHC-independent immune effectors such as natural killer (NK), and cytokine-induced killer (CIK). Adoptive cell therapy (ACT) has shown activity in several pre-clinical models. Available preclinical and clinical data suggest that adoptive cell therapy may provide the best benefit in settings of low tumor burden, minimal residual disease, or maintenance therapy. Further studies are needed to better define the optimal clinical setting.

Lenalidomide normalizes tumor vessels in colorectal cancer improving chemotherapy activity

Background

Angiogenesis inhibition is a promising approach for treating metastatic colorectal cancer (mCRC). Recent evidences support the seemingly counterintuitive ability of certain antiangiogenic drugs to promote normalization of residual tumor vessels with important clinical implications. Lenalidomide is an oral drug with immune-modulatory and anti-angiogenic activity against selected hematologic malignancies but as yet little is known regarding its effectiveness for solid tumors. The aim of this study was to determine whether lenalidomide can normalize colorectal cancer neo-vessels in vivo, thus reducing tumor hypoxia and improving the benefit of chemotherapy.

Methods

We set up a tumorgraft model with NOD/SCID mice implanted with a patient-derived colorectal cancer liver metastasis. The mice were treated with oral lenalidomide (50 mg/Kg/day for 28 days), intraperitoneal 5-fluorouracil (5FU) (20 mg/Kg twice weekly for 3 weeks), combination (combo) of lenalidomide and 5FU or irrelevant vehicle. We assessed tumor vessel density (CD146), pericyte coverage (NG2; alphaSMA), in vivo perfusion capability of residual vessels (lectin distribution essay), hypoxic areas (HP2-100 Hypoxyprobe) and antitumor activity in vivo and in vitro.

Results

Treatment with lenalidomide reduced tumor vessel density (p = 0.0001) and enhanced mature pericyte coverage of residual vessels (p = 0.002). Perfusion capability of tumor vessels was enhanced in mice treated with lenalidomide compared to controls (p = 0.004). Accordingly, lenalidomide reduced hypoxic tumor areas (p = 0.002) and enhanced the antitumor activity of 5FU in vivo. The combo treatment delayed tumor growth (p = 0.01) and significantly reduced the Ki67 index (p = 0.0002). Lenalidomide alone did not demonstrate antitumor activity compared to untreated controls in vivo or against 4 different mCRC cell lines in vitro.

Conclusions

We provide the first evidence of tumor vessel normalization and hypoxia reduction induced by lenalidomide in mCRC in vivo. This effect, seemingly counterintuitive for an antiangiogenic compound, translates into indirect antitumor activity thus enhancing the therapeutic index of chemotherapy. Our findings suggest that further research should be carried out on synergism between lenalidomide and conventional therapies for treating solid tumors that might benefit from tumor vasculature normalization.

Effect of chaetocin on renal cell carcinoma cells and cytokine-induced killer cells

We examined the cytotoxic effects of chaetocin on clear cell renal cell carcinoma (ccRCC) cells and the possibility to combine the effects of chaetocin with the effects of cytokine-induced killer cells (CIK) assayed by MTT assay and FACS analysis. Chaetocin is a thiodioxopiperazine produced by fungi belonging to the chaetomiaceae family. In 2007, it was first reported that chaetocin shows potent and selective ex vivo anti-cancer activity by inducing reactive oxygen species. CIK cells are generated from CD3+/CD56- T lymphocytes with double negative CD4-/CD8- phenotype that are isolated from human blood. The addition of distinct interleukins and antibodies results in the generation of CIK cells that are able to specifically target and destroy renal carcinoma cells. The results of this research state that the anti-ccRCC activity of chaetocin is weak and does not show a high grade of selectivity on clear cell renal cell carcinoma cells. Although the CIK cells show a high grade of selective anti-ccRCC activity, this effect could not be improved by the addition of chaetocin. So chaetocin seems to be no suitable agent for specific targeting ccRCC cells or for the combination therapy with CIK cells in renal cancer.

Effect of cytokine-induced killer cells on immune function in patients with lung cancer

Cytokine-induced killer (CIK) cells have been used as adoptive immunotherapy in cancer. The present study evaluated the effect of CIK cells on immune function in patients with lung cancer. Patients were divided into three groups, according to the treatment received prior to CIK cell treatment: CIK group (no prior treatment), Che-Sur group (prior chemotherapy and surgery) and Che-Rad group (prior chemotherapy and radiotherapy). Following treatment, the average percentage of cluster of differentiation (CD)3⁺CD4⁺, CD3⁺, natural killer (NK) and NKT cells in peripheral blood was significantly higher than that prior to CIK treatment in the Che-Sur and CIK groups, and the levels of interferon-γ in serum were significantly higher than those prior to CIK treatment in the Che-Sur and CIK groups. On the contrary, the levels of interleukin-10 had decreased in these groups following CIK treatment. Subsequently, patients were divided into three groups according to the percentage of CD3⁺CD56⁺ CIK cells that were administered to the patients. The number of NK and NKT cells increased with increasing number of CD3⁺CD56⁺ cells. The patients in the CIK and Che-Sur groups were the most benefited ones following CIK treatment, contrarily to those in the Che-Rad group, since the increase in the number of CD3⁺CD56⁺ CIK cells in the aforementioned patients enhanced the number of NK cells, which exhibit antitumor activity.