Selective homing of CAR-CIK cells to the bone marrow niche enhances control of the acute myeloid leukemia burden.

Acute myeloid leukemia (AML) is a hematological malignancy derived from neoplastic myeloid progenitor cells characterized by abnormal clonal proliferation and differentiation. Although novel therapeutic strategies have recently been introduced, the prognosis of AML is still unsatisfactory. So far, the efficacy of chimeric antigen receptor (CAR)-T-cell therapy in AML has been hampered by several factors, including the poor accumulation of the blood-injected cells in the leukemia bone marrow (BM) niche in which chemotherapy-resistant leukemic stem cells reside. Thus, we hypothesized that overexpression of CXCR4, whose ligand CXCL12 is highly expressed by BM stromal cells within this niche, could improve T-cell homing to the BM and consequently enhance their intimate contact with BM-resident AML cells, facilitating disease eradication. Specifically, we engineered conventional CD33.CAR-cytokine-induced killer cells (CIKs) with the wild-type (wt) CXCR4 and the variant CXCR4R334X, responsible for leukocyte sequestration in the BM of patients with warts, hypogammaglobulinemia, immunodeficiency, and myelokathexis syndrome. Overexpression of both CXCR4wt and CXCR4mut in CD33.CAR-CIKs resulted in significant improvement of chemotaxis toward recombinant CXCL12 or BM stromal cell-conditioned medium, with no observed impairment of cytotoxic potential in vitro. Moreover, CXCR4-overexpressing CD33.CAR-CIKs showed enhanced in vivo BM homing, associated with a prolonged retention for the CXCR4R334X variant. However, only CD33.CAR-CIKs coexpressing CXCR4wt but not CXCR4mut exerted a more sustained in vivo antileukemic activity and extended animal survival, suggesting a noncanonical role for CXCR4 in modulating CAR-CIK functions independent of BM homing. Taken together, these data suggest that arming CAR-CIKs with CXCR4 may represent a promising strategy for increasing their therapeutic potential for AML.

Immunophenotype and antitumor activity of cytokine-induced killer cells from patients with hepatocellular carcinoma.

BACKGROUND: Cytokine-induced killer (CIK) cells are heterogeneous lymphocytes from human peripheral blood mononucleated cells (PBMCs) co-cultured with several cytokines. The main purpose of this study is to evaluate the functional characteristics and anticancer ability of CIK cells from hepatocarcinoma (HCC) patients. METHODS: CIK cells were activated ex-vivo and expanded from PBMCs from HCC patients. The immunophenotype and the ex-vivo killing ability of CIK cells were evaluated. Human CIK cells were intravenously injected into NOD/SCID mice to evaluate the in vivo anticancer ability. RESULTS: More than 70% of CIK cells were CD3+CD8+, and 15%-30% were CD3+CD56+. These cells expressed an increased number of activated natural killer (NK) receptors, such as DNAM1 and NKG2D, and expressed low-immune checkpoint molecules, including PD-1, CTLA-4, and LAG-3. Among the chemokine receptors expressed by CIKs, CXCR3 and CD62L were elevated in CD8+ T cells, representing the trafficking ability to inflamed tumor sites. CIK cells possess the ex-vivo anticancer activity to different cell lines. To demonstrate in vivo antitumor ability, human CIK cells could significantly suppress the tumor of J7 bearing NOD/SCID mice. Furthermore, human immune cells could be detected in the peripheral blood and on the tumors after CIK injection. CONCLUSIONS: This study revealed that CIK cells from HCC patients possess cytotoxic properties, and express increased levels of effector NK receptors and chemokine molecules and lower levels of suppressive checkpoint receptors. CIK cells can suppress human HCC ex-vivo and in vivo. Future clinical trials of human CIK cell therapy for HCC are warranted.

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. Video abstract.

Adoptive cell therapies in thoracic malignancies.

Immunotherapy has gained great interest in thoracic malignancies in the last decade, first in non-small cell lung cancer (NSCLC), but also more recently in small-cell lung cancer (SCLC) and malignant pleural mesothelioma (MPM). However, while 15-20% of patients will greatly benefit from immune checkpoint blockers (ICBs), a vast majority will rapidly exhibit resistance. Reasons for this are multiple: non-immunogenic tumors, immunosuppressive tumor microenvironment or defects in immune cells trafficking to the tumor sites being some of the most frequent. Current progress in adoptive cell therapies could offer a way to overcome these hurdles and bring effective immune cells to the tumor site. In this review, we discuss advantages, limits and future perspectives of adoptive cell therapy (ACT) in thoracic malignancies from lymphokine-activated killer cells (LAK), cytokine-induced killer cells (CIK), natural killer cells (NK), dendritic cells (DC) vaccines and tumor-infiltrating lymphocytes (TILs) to TCR engineering and CARs. Trials are still in their early phases, and while there may still be many limitations to overcome, a combination of these different approaches with ICBs, chemotherapy and/or radiotherapy could vastly improve the way we treat thoracic cancers.

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.

Presence of the Transmembrane Protein Neuropilin in Cytokine-induced Killer Cells.

BACKGROUND/AIM: Cytokine-induced killer (CIK) cells are a heterogenous population of immune cells showing promising applications in immunotherapeutic cancer treatment. Neuropilin (NRP) proteins have been proven to play an important role in cancer development and prognosis. In this study, CIK cells were tested for expression of NRPs, transmembrane proteins playing a role in the proliferation and survival of cancer cells. MATERIALS AND METHODS: CIK cells were analyzed at different time points via flow cytometry and quantitative real-time polymerase chain reaction for neuropilin expression. RESULTS: Phenotyping results showed CIK cells having developed properly, and low levels of NRP2 were detected. On the other hand, no NRP1 expression was found. Two cancer cell lines were tested by flow cytometry: A549 cells expressed NRP1 and NRP2; U251-MG cells expressed high amounts of NRP2. CIK cell showed low levels of NRP2 expression on day 14. CONCLUSION: The presence of NRP2, but not NRP1, was shown for CIK cells. Recognizing NRP2 in CIK cells might help to improve CIK cell cytotoxicity.

Clearance of Hematologic Malignancies by Allogeneic Cytokine-Induced Killer Cell or Donor Lymphocyte Infusions.

Well-established donor lymphocyte infusion (DLI) and novel cytokine-induced killer (CIK) cell therapy for the treatment of relapsing hematologic malignancies after allogeneic hematopoietic stem cell transplantation (HSCT) were compared with respect to feasibility, safety, and efficacy. Altogether, a total of 221 infusions were given to 91 patients (DLI, n = 55; CIK, n = 36). T cell recovery was significantly improved after CIK cell therapy (P < .0001). Although patients with CIK cell treatment showed a significantly worse prognosis at the time of HSCT (risk score, 1.7 versus 2.1; P < .0001), DLI and CIK cell therapy induced complete remission (CR) in 29% and 53% patients, respectively, whereas relapse occurred in 71% and 47%. In both groups, all patients with overt hematologic relapse at the time of immunotherapy (DLI, n = 11; CIK, n = 8) succumbed to their disease, while 36% and 68% patients with DLI or CIK cell therapy applied due to molecular relapse or active disease at the time of transplantation achieved CR. The 6-month overall survival rate in the latter patients was 57% and 77%, respectively, with a median follow-up of 27.9 months (range, .9 to 149.2 months). The 6-month cumulative incidence of relapse was 55% and 22% in patients who received DLI and CIK cell therapy, respectively (P = .012). Acute graft-versus-host disease developed in 35% of the patients who received DLI and in 25% of those who received CIK. No transfusion-related deaths occurred. These data, while underscoring the therapeutic value of conventional DLI, suggest the improved safety and to a certain extent efficacy of CIK cell therapy for patients at high risk for post-transplantation relapse of various hematologic malignancies.

Phase Ib/II study of safety and efficacy of low-dose decitabine-primed chemoimmunotherapy in patients with drug-resistant relapsed/refractory alimentary tract cancer.

The pressing need for improved therapeutic outcomes provides a good rationale for identifying effective strategies for alimentary tract (AT) cancer treatment. The potential re-sensitivity property to chemo- and immunotherapy of low-dose decitabine has been evident both preclinically and in previous phase I trials. We conducted a phase Ib/II trial evaluating low-dose decitabine-primed chemoimmunotherapy in patients with drug-resistant relapsed/refractory (R/R) esophageal, gastric or colorectal cancers. Forty-five patients received either the 5-day decitabine treatment with subsequent readministration of the previously resistant chemotherapy (decitabine-primed chemotherapy, D-C cohort) or the aforementioned regimen followed by cytokine-induced killer cells therapy (D-C and cytokine-induced killer [CIK] cell treatment, D-C + CIK cohort) based on their treatment history. Grade 3 to 4 adverse events (AEs) were reported in 11 (24.4%) of 45 patients. All AEs were controllable, and no patient experienced a treatment-related death. The objective response rate (ORR) and disease control rate (DCR) were 24.44% and 82.22%, respectively, including two patients who achieved durable complete responses. Clinical response could be associated with treatment-free interval and initial surgical resection history. ORR and DCR reached 28% and 92%, respectively, in the D-C + CIK cohort. Consistently, the progression-free survival (PFS) of the D-C + CIK cohort compared favorably to the best PFS of the pre-resistant unprimed therapy (p = 0.0001). The toxicity and ORRs exhibited were non-significantly different between cancer types and treatment cohort. The safety and efficacy of decitabine-primed re-sensitization to chemoimmunotherapy is attractive and promising. These data warrant further large-scale evaluation of drug-resistant R/R AT cancer patients with advanced stage disease.

Cytokine-induced killer cells hunt individual cancer cells in droves in a mouse model.

Cytotoxicity of cytokine-induced killer (CIK) cells depends mainly on their encounters with target cells, but how many CIK cells are required to kill an individual cancer cell is unknown. Here we used time-lapse imaging to quantify the critical effector cell number required to kill an individual target cell. CIK cells killed MHC-I-negative and MHC-I-positive cancer cells, but natural killer (NK) cells destroyed MHC-I-negative cells only. The average threshold number of CIK cells required to kill an individual cancer cell was 6.7 for MHC-I-negative cells and 6.9 for MHC-I-positive cells. That of NK cells was 2.4 for MHC-I-negative cells. Likely due to the higher threshold numbers, killing by CIK cells was delayed in comparison with NK cells: 40% of MHC-negative target cells were killed after 5 h when co-cultured with CIK cells and after 2 h with NK cells. Our data have implications for the rational design of CIK cell-based immunotherapy of cancer patients.

Selective effect of cytokine-induced killer cells on survival of patients with early-stage melanoma.

Adoptive immunotherapy using cytokine-induced killer (CIK) cells has shown potential antitumor ability against several kinds of cancers, including melanoma. However, little is known about the achievable outcome of CIK cells in melanoma patients at different pathological stages. Here we recruited 55 patients treated with conventional therapy plus CIK cells as the CIK group, and 49 patients treated with conventional therapy alone as the control group. The pathological characteristics were comparable between two groups, with a follow-up period up to 40 months. Survival data and immune responses were evaluated after CIK cell treatment. In this study, CIK cells were successfully generated from peripheral blood of melanoma patients after in vitro culture for 14 days. The cultured CIK cells not only produced high levels of pro-inflammatory cytokines upon in vitro stimulation but also efficiently killed human melanoma cell lines. No serious side events were observed in all patients treated with CIK cells. Furthermore, infusions of CIK cells improved the quality of life in some patients, including advanced cases. More importantly, the CIK group exhibited better survival rates compared to the control group among early-stage melanoma patients, in consistent with the increased frequency of peripheral CD4+ T cells. However, the patients with advanced-stage melanoma did not benefit from the CIK cell therapy in terms of survival rate. In conclusion, CIK cells combined with conventional treatments may prolong the survival of early-stage melanoma patients and improve the quality of life for some advanced cases in a safe way.

The Efficacy of CIK-Based Immunotherapies for Advanced Solid Tumors.

OBJECTIVE: To investigate the efficacy of cytokine-induced killer cell-based immunotherapies in patients with advanced malignant solid tumors and the difference in clinical efficiency among 3 kinds of cytokine-induced killer cell-based immunotherapies. METHODS: One hundred forty-six cases with advanced solid tumor, 230 cycles of cytokine-induced killer cell-based immunotherapies, were involved in this study. T-lymphocyte subsets, carcinoembryonic antigen, and adverse reactions were recorded. RESULTS: CD3+ T lymphocyte, Th, NKT, and Th/Tc were increased after cytokine-induced killer cell-based treatment, from 55.67 ± 3.64 to 84.12 ± 5.15, 26.56 ± 4.47 to 42.76 ± 3.68, 1.82 ± 0.58 to 7.08 ± 0.92, 0.79 ± 3.64 to 1.35 ± 0.20, respectively ( P < .001). Carcinoembryonic antigen was decreased from 398.39 ± 219.16 to 127.26 ± 153.41 ( P < .001). Difference values were greater than 0 ( P < .001). Difference value of carcinoembryonic antigen was obviously less than 0 ( P < .001). There was no obvious difference in all variations between cytokine-induced killer cell and DC+CIK groups ( P > .05). The highest amount of CD3+ T lymphocyte and Th was recorded after at least 4 cycles of immunotherapy. And CD8+ T/CD4+ T also began to decrease after 4 cycles of immunotherapy. Difference value of T lymphocyte and Tc of patients with surgery is higher than that of patients without surgery. CONCLUSION: Cytokine-induced killer cell-based immunotherapy is capable of increasing T-lymphocyte subsets, recovering cellular immunity without severe side effects, and is suitable for different kinds of solid cancer. Clinical efficiency of cytokine-induced killer cell-based immunotherapy is influenced by many factors such as surgery, stage.

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.

Augmented CD3(+)CD8(+) and CD3(+)CD56(-) cells in cytokine-induced killer cells cultured with engineered cells for costimulatory enhancement from heavily pretreated patients with solid tumor.

BACKGROUND AIMS: Cytokine-induced killer cells (CIKs) were shown to be a promising tool in the quest for new therapeutic approaches in the setting of metastatic solid tumors refractory to standard treatments. However, there is a practical clinical problem of different expansion rates and cell function as individual variability exists. Stimulatory molecular 4-1BB could promote division and survival of T cells and enhance effector activity including cytokine production. This study aimed to invest the contribution of co-stimulation signal to CIKs production for exploring new strategies, which increase the expansion and reliability of CIKs generation to improve access to CIKs therapy. METHODS: We studied the larger-scale expansion of CIKs cultured with engineered cells for costimulatory enhancement (ECCE) consisting of K562 cells that expressed 4-1BBL in heavily pretreated patients with solid tumor. The proliferation and cytotoxic capacity of CIKs were evaluated. Phenotypes of CIKs were analyzed using flow cytometry. Cytokine levels of interferon (IFN)-γ and tumor necrosis factor (TNF)-α were detected using enzyme-linked immunosorbent assay (ELISA). RESULTS: The proliferation and cytotoxic activity of CIKs were significantly up-regulated by ECCE. The percentages of CD3(+)CD8(+) and CD3(+)CD56(-) CIKs were significantly increased while the percentage of CD3(+)CD56(+) CIKs was decreased. In addition, the secretion of IFN-γ and TNF-α by CIKs could also be enhanced significantly when ECCE were added into the culture system. CONCLUSIONS: This study suggests that ECCE may improve the efficacy of CIKs therapy and make CIKs therapy possible for the patients whose CIKs would be hard to be cultured using conventional methods.

Increased effect of IMiDs by addition of cytokine-induced killer cells in multiple myeloma.

Immunomodulatory drugs (IMiDs), such as thalidomide, lenalidomide and pomalidomide, represent the basic principle of multiple myeloma treatment. However, the development of resistance is a limiting factor. Over the last years, the efficient application of cytokine-induced killer (CIK) cells has been reported as an alternative strategy to treat hematological neoplasms. In this study, we tested for a potential synergistic effect by combining the IMiDs thalidomide, lenalidomide and pomalidomide with CIK cells in different myeloma cell lines in vitro. Myeloma cells tested with CIK cells were significantly reduced. In the combination, myeloma cells were significantly reduced compared with cells only tested with IMiDs but not to the cells tested with CIK cells. Otherwise, the number of CIK cells was significantly reduced when treated with IMiDs. Because IMiDs are active in patients with myeloma, these results lead to the expectation that combination of IMiDs and CIK cells achieve better results in the treatment of multiple myeloma compared with the single use of IMiDs. Therefore, further examinations in an in vivo setting are necessary to have a closer look on the cellular interactions. Copyright © 2015 John Wiley & Sons, Ltd.

Combination of radiofrequency ablation and sequential cellular immunotherapy improves progression-free survival for patients with hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) recurs frequently after minimally invasive therapy. The aim of our study was to observe the efficiency and safety of the combined treatment of radiofrequency ablation (RFA) with cellular immunotherapy (CIT) for HCC patients. In our study, 62 patients with HCC who were treated with radical RFA were divided into two groups: RFA alone (32 patients) and RFA/CIT (30 patients). Autologous mononuclear cells were collected from the peripheral blood and separated by apheresis, and then induced into natural killer (NK) cells, γδT cells and cytokine-induced killer (CIK) cells. These cells were identified by flow cytometry with their specific antibodies and then were infused intravenously to RFA/CIT patients for three or six courses. The tumor recurrent status of these patients was evaluated with computed tomography or magnetic resonance imaging every 3 months after RFA. Progression-free survival (PFS), liver function, viral load and adverse effects were examined. The results implied that PFS was higher in RFA/CIT group than that in RFA group. In RFA/CIT group, six courses had better survival prognosis than three courses. Viral load of hepatitis C was decreased in two of three patients without antiviral therapy in RFA/CIT group, but was increased in RFA group. No significant adverse reaction was found in the patients with CIT. In summary, these preliminary results suggest that combination of sequential CIT with RFA for HCC patients was efficient and safe, and may be helpful in the prevention of the recurrence for the patients with HCC after RFA.

Cytokine-induced killer cells in combination with transcatheter arterial chemoembolization and radiofrequency ablation for hepatocellular carcinoma patients.

This study evaluated the clinical efficacy of autologous cytokine-induced killer (CIK) cell transfusion in combination with transcatheter arterial chemoembolization (TACE) and radiofrequency ablation (RFA), compared to sequential therapy with TACE and RFA, for the treatment of hepatocellular carcinoma (HCC). We retrospectively studied 2 groups of HCC patients: 85 patients in the TACE+RFA+CIK group were treated with adoptive autologous CIK cell transfusion in combination with minimally invasive therapy, 89 patients in the TACE+RFA group were treated with minimally invasive therapy alone. The overall response rate was 76.5% in the TACE+RFA+CIK group and 79.8% in the TACE+RFA group. The disease control rate was higher in the TACE+RFA+CIK group than that in the TACE+RFA group (95.3% vs. 88.8%), but the difference was not significant (P=0.113). Kaplan-Meier analysis showed that the patients in the TACE+RFA+CIK group had significantly longer overall survival (56 vs. 31 mo, P=0.001) and progression-free survival (17 vs. 10 mo, P=0.001) than those in the TACE+RFA group. No severe side effects occurred in the CIK cell transfusion patients. In conclusion, CIK cell immunotherapy may be a valuable therapeutic strategy to prevent recurrence and metastasis in HCC patients after TACE and RFA, and to improve patient prognosis and quality of life. Combined CIK immunotherapy and minimally invasive therapies represent a safe, potential treatment modality for HCC. However, because patient assignment to the 2 treatments was not randomized, any conclusions concerning improvements in survival must be interpreted with great caution.

Improved activation toward primary colorectal cancer cells by antigen-specific targeting autologous cytokine-induced killer cells.

Adoptive therapy of malignant diseases with cytokine-induced killer (CIK) cells showed promise in a number of trials; the activation of CIK cells from cancer patients towards their autologous cancer cells still needs to be improved. Here, we generated CIK cells ex vivo from blood lymphocytes of colorectal cancer patients and engineered those cells with a chimeric antigen receptor (CAR) with an antibody-defined specificity for carcinoembryonic antigen (CEA). CIK cells thereby gained a new specificity as defined by the CAR and showed increase in activation towards CEA⁺ colon carcinoma cells, but less in presence of CEA⁻ cells, indicated by increased secretion of proinflammatory cytokines. Redirected CIK activation was superior by CAR-mediated CD28-CD3ζ than CD3ζ signaling only. CAR-engineered CIK cells from colon carcinoma patients showed improved activation against their autologous, primary carcinoma cells from biopsies resulting in more efficient tumour cell lysis. We assume that adoptive therapy with CAR-modified CIK cells shows improved selectivity in targeting autologous tumour lesions.

Coculturing dendritic cells with zoledronate acid efficiently enhance the anti-tumor effects of cytokine-induced killer cells.

INTRODUCTION: Dendritic cells (DCs) have greater stimulating activity on innate and adaptive immunity following short-term sensitization with zoledronate acid (DCs(Zol)). We identified the phenotype, cytotoxicity, and mechanisms of killing of cytokine-induced killer (CIK) cells which were cocultured with DCs(Zol). METHODS: Adherent and nonadherent cells of peripheral blood mononuclear cell from myeloma patients were incubated for DCs and CIK cells. Then, the CIK cells were cocultured with DCs(Zol) (DCs(Zol)-CIK). Expression of markers for DCs(Zol)-CIK cells was measured using flow cytometry. Cytotoxicity was evaluated by against human myeloma cell lines and mechanisms of killing were tested by selectively blocking NKG2D receptor. The anti-tumor activity of these effector cells was further evaluated using a nude mice tumor model. RESULTS: gammadelta TCR expression of CIK cells significantly increased after coculture with immature or mature DCs(Zol) (iDCs/mDCs(Zol)-CIK) and these cells aggressively lysed myeloma cells compared with mDCs-CIK and zoledronate acid pulsed CIK cells (CIK(Zol); 50.8 +/- 7.9% and 48.2 +/- 4.7% versus 31.9 +/- 5.1% and 20.5 +/- 3.6%, effector versus target ratio was 60:1). Both alphabeta T and gammadelta T cells in the iDCs(Zol)-CIK cells performed the majority of lysis. The iDCs/mDCs(Zol)-CIK cells greatly increased NKG2D expression compared with mDCs-CIK and CIK(Zol) during culture (71.5 +/- 11.3% and 67.7 +/- 9.3% versus 51.3 +/- 6.2% and 47.1 +/- 5.7%). iDCs(Zol)-CIK cell-mediated lysis dropped 69.21% when the NKG2D receptor was blocked and the cytotoxicity correlated with NKG2D ligand-MICA expression on the target cells. In a human myeloma bearing nude mice model, iDCs(Zol)-CIK and mDCs(Zol)-CIK cells treatment groups obtained 75% and 62.5% long-term survival (>120 days) respectively, as compared with none of the control animals or 37.5% treated with mDCs-CIK cells. CONCLUSION: Large numbers of CIK cells with greater anti-tumor activities are rapidly generated by Zol-treated iDCs/mDCs. This strategy is worthy of further investigation to improve adoptive cell therapy against tumors.

[The cytotoxicity and mechanism of CIK cells to breast cancer cells ZK-75-1].

AIM: To study the cytotoxicity and mechanism of cytokine-induced killer (CIK) cells to breast cancer cell line ZK-75-1. METHODS: The morphological changes of ZK-75-1 cells were observed by HE staining. The apoptosis of ZK-75-1 cell line was examined by TUNEL staining. The expression of P53, P16, C-myc, Bcl-2 and Bax was determined by immunocytochemical staining. RESULTS: The result of HE staining revealed that CIK cells moved toward the target cells, forming typical rosette cells. Granule-like substances appeared in cytoplasm of tumor cells, but only granule-shape patch was found in some tumor cells while breast cancer cells as control grew well. TUNEL staining indicated that the cells in control group were not stained or dyed well-distributed light blue. As the cells in experiment group became smaller, mucleoluser or perinuclear was dyed deep blue. The apoptotic rate of ZK-75-1 cells cocultured with CIK cells was increased after 4-12 hours and was decreased after 12-24 hours, with a significant difference compared with control group (P<0.01). Immunocytochemical staining showed that the expression of p53, p16, C-myc and Bcl-2 proteins in CIK group declined but the expression of Bax protein increased with the passage of time, which was significantly different compared with control (P<0.01). CONCLUSION: The mechanism of killing ZK-75-1 cells by CIK cells is closely related to the downregulation of the expression of P53, P16, c-myc and Bcl-2 proteins and to the upregulation of the expression of Bax protein. It also has close relation with the time of exposure to CIK cells.