Implication of combined PD-L1/PD-1 blockade with cytokine-induced killer cells as a synergistic immunotherapy for gastrointestinal cancer. Oncotarget. 2016;7:10332-10344. [PMID: 26871284 PMCID: PMC4891123 DOI: 10.18632/oncotarget.7243]

Anlotinib and anti-PD-1 mAbs perfected CIK cell therapy for lung adenocarcinoma in preclinical trials

Murine cytokine-induced killer (CIK) cells are heterologous cells that kill various allogeneic and isogenic tumors and have functional and phenotypic characteristics of natural killer cells and T lymphocytes. However, the effect of CIK cells alone on solid tumor therapy is only limited. To enhance the therapeutic effect, it is vital to discover a mix of several therapy approaches. Immune cell function is inhibited by abnormal tumor vessels and the tumor microenvironment, which block lymphocyte entry into tumor tissue. To increase the effectiveness of CIK cells' antitumor activity, antivascular therapy and CIK cell therapy can be combined. Furthermore, anlotinib is a tiny drug with multitarget tyrosine kinase inhibitors that can block cell migration, delay angiogenesis, and decrease blood vessel density. Compared with other antiangiogenesis drugs, anlotinib stands out due to the wider target of action and lower effective dose. In this work, anlotinib and murine CIK cells were coupled to boost CD3+ T cell infiltration, CD3+CD4+ T cell infiltration, and expression of granzyme B and interferon γ from CD3+CD8+ T cells, which increased the antitumor activity. Through the generation of cytotoxic cytokines by T lymphocytes, the therapeutic group using anti-PD-1 monoclonal antibodies in conjunction with anlotinib and CIK cells was more successful than the group receiving dual therapy. The preclinical study contributes to exploring the therapeutic alternatives for patients with lung adenocarcinoma, thus prolonging their lives.

Clinical application of cytokine-induced killer (CIK) cell therapy in colorectal cancer: Current strategies and future challenges

Colorectal cancer (CRC) remains a significant global health burden and is the second leading cause of cancer-related death. Cytokine induced killer (CIK) cell therapy is an immunotherapy which has the potential to meet this need. Clinical trials of CIK cell therapy for the management of CRC have reported improved clinical outcomes. However, production and delivery protocols varied significantly, and many studies were reported only in Chinese language journals. Here we present the most comprehensive review of the clinical CIK cell therapy trials for CRC management to date. We accessed both English and Chinese language clinical studies, and summarise how CIK cell therapy has been implemented, from manufacturing to patient delivery. We discuss current challenges that impede wider adoption of CIK cell therapy in CRC management.

Clinical Applications of Combined Immunotherapy Approaches in Gastrointestinal Cancer: A Case-Based Review

Malignant neoplasms arising from the gastrointestinal (GI) tract are among the most common types of cancer with high mortality rates. Despite advances in treatment in a small subgroup harboring targetable mutations, the outcome remains poor, accounting for one in three cancer-related deaths observed globally. As a promising therapeutic option in various tumor types, immunotherapy with immune checkpoint inhibitors has also been evaluated in GI cancer, albeit with limited efficacy except for a small subgroup expressing microsatellite instability. In the quest for more effective treatment options, energetic efforts have been placed to evaluate the role of several immunotherapy approaches comprising of cancer vaccines, adoptive cell therapies and immune checkpoint inhibitors. In this review, we report our experience with a personalized dendritic cell cancer vaccine and cytokine-induced killer cell therapy in three patients with GI cancers and summarize current clinical data on combined immunotherapy strategies.

Combination of FAK inhibitor and cytokine-induced killer cell therapy: An alternative therapeutic strategy for patients with triple-negative breast cancer

Triple-negative breast cancer (TNBC) is characterized by the loss of expression of several biomarkers, which limits treatment strategies for the disease. In recent years, immunotherapy has shown promising results in the treatment of various tumors. Emerging evidence demonstrated that TNBC is an immune-activated cancer, suggesting that immunotherapy could be a feasible treatment option for TNBC. Cytokine-induced killer (CIK) cell therapy is considered as a potential treatment for cancer treatment. However, it is still not approved as a standard treatment in the clinical setting. Our previous study demonstrated that focal adhesion kinase (FAK) plays important role in regulating the sensitivity of TNBC cells to CIK cells. In this study, we further verify the role of FAK in regulating the immune response in vivo. Our in vitro study indicated that knockdown of FAK in TNBC cells or treat with the FAK inhibitor followed by co-culture with CIK cells induced more cell death than CIK cells treatment only. RNA-seq analysis indicated that suppression of FAK could affect several immune-related gene expressions in TNBC cells that affects the immune response in the tumor microenvironment of TNBC cells. The combination of FAK inhibitor and CIK cells significantly suppressed tumor growth than the treatment of FAK inhibitor or CIK cells alone in vivo. Our findings provide new insights into the cytotoxic effect of CIK cell therapy in TNBC treatment and indicate that the combination of CIK cell therapy with FAK inhibitors may be an alternative therapeutic strategy for patients with TNBC.

Dual inhibition of IDO1/TDO2 enhances anti-tumor immunity in platinum-resistant non-small cell lung cancer

BACKGROUND

The impact of non-small cell lung cancer (NSCLC) metabolism on the immune microenvironment is not well understood within platinum resistance. We have identified crucial metabolic differences between cisplatin-resistant (CR) and cisplatin-sensitive (CS) NSCLC cells with elevated indoleamine 2,3-dioxygenase-1 (IDO1) activity in CR, recognized by increased kynurenine (KYN) production.

METHODS

Co-culture, syngeneic, and humanize mice models were utilized. C57BL/6 mice were inoculated with either Lewis lung carcinoma mouse cells (LLC) or their platinum-resistant counterpart (LLC-CR) cells. Humanized mice were inoculated with either A (human CS cells) or ALC (human CR cells). Mice were treated with either IDO1 inhibitor or TDO2 (tryptophan 2,3-dioxygenase-2) inhibitor at 200 mg/kg P.O. once a day for 15 days; or with a new-in-class, IDO1/TDO2 dual inhibitor AT-0174 at 170 mg/kg P.O. once a day for 15 days with and without anti-PD1 antibody (10 mg/kg, every 3 days). Immune profiles and KYN and tryptophan (TRP) production were evaluated.

RESULTS

CR tumors exhibited a more highly immunosuppressive environment that debilitated robust anti-tumor immune responses. IDO1-mediated KYN production from CR cells suppressed NKG2D on immune effector natural killer (NK) and CD8⁺ T cells and enhanced immunosuppressive populations of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Importantly, while selective IDO1 inhibition attenuated CR tumor growth, it concomitantly upregulated the TDO2 enzyme. To overcome the compensatory induction of TDO2 activity, we employed the IDO1/TDO2 dual inhibitor, AT-0174. Dual inhibition of IDO1/TDO2 in CR mice suppressed tumor growth to a greater degree than IDO1 inhibition alone. Significant enhancement in NKG2D frequency on NK and CD8⁺ T cells and a reduction in Tregs and MDSCs were observed following AT-1074 treatment. PD-L1 (programmed death-ligand-1) expression was increased in CR cells; therefore, we assessed dual inhibition + PD1 (programmed cell death protein-1) blocking and report profound anti-tumor growth and improved immunity in CR tumors which in turn extended overall survival in mice.

CONCLUSION

Our study reports the presence of platinum-resistant lung tumors that utilize both IDO1/TDO2 enzymes for survival, and to escape immune surveillance as a consequence of KYN metabolites. We also report early in vivo data in support of the potential therapeutic efficacy of the dual IDO1/TDO2 inhibitor AT-0174 as a part of immuno-therapeutic treatment that disrupts tumor metabolism and enhances anti-tumor immunity.

Revising the Landscape of Cytokine-Induced Killer Cell Therapy in Lung Cancer: Focus on Immune Checkpoint Inhibitors

Undeniably, immunotherapy has markedly improved the survival rate of cancer patients. The scenario is no different in lung cancer, where multiple treatment options are now available and the inclusion of immunotherapy yields better clinical benefits than previously used chemotherapeutic strategies. Of interest, cytokine-induced killer (CIK) cell immunotherapy has also taken a central role in clinical trials for the treatment of lung cancer. Herein, we describe the relative success of CIK cell therapy (alone and combined with dendritic cells as DC/CIKs) in lung cancer clinical trials and discuss its combination with known immune checkpoint inhibitors (anti-CTLA-4 and anti-PD-1/PD-L1). Additionally, we provide insights into the findings of several preclinical in vitro/in vivo studies linked to lung cancer. In our opinion, CIK cell therapy, which recently completed 30 years and has been approved in many countries, including Germany, offers tremendous potential for lung cancer. Foremost, when it is optimized on a patient-by-patient basis with special attention to the patient-specific genomic signature.

PD-1/PD-L1 blockade inhibits epithelial-mesenchymal transition and improves chemotherapeutic response in breast cancer

Therapies targeting the PD-1/PD-L1 axis have recently been implemented for triple negative breast cancer (TNBC) management with limited efficacy, indicating that this axis may promote tumor growth by means other than immune suppression. Because PD-L1 overexpression causes resistance to the chemotherapeutic response in many cancers, here we explored the tumor promoting role of the PD-1/PD-L1 axis in breast cancer. We observed that the downregulation of PD-L1 by specific siRNA and pharmacological inhibitor significantly suppressed tumor cell proliferation, invasion and migration thereby enhancing T cell-mediated cell killing in vitro. We also showed that inhibiting PD-L1 improves cytotoxic sensitivity to chemotherapy in TNBC cells. Our in vivo results confirmed that combining a PD-L1 inhibitor with chemotherapy could significantly reduce tumor progression by inhibiting epithelial-mesenchymal transition. Overall, our results proved that PD-L1 contributes to the transformation and progression of breast cancer cells and that its intervention is a promising therapeutic strategy against breast cancer.

A versatile, high-efficiency platform for CRISPR-based gene activation

CRISPR-mediated transcriptional activation (CRISPRa) is a powerful technology for inducing gene expression from endogenous loci with exciting applications in high throughput gain-of-function genomic screens and the engineering of cell-based models. However, current strategies for generating potent, stable, CRISPRa-competent cell lines present limitations for the broad utility of this approach. Here, we provide a high-efficiency, self-selecting CRISPRa enrichment strategy, which combined with piggyBac transposon technology enables rapid production of CRISPRa-ready cell populations compatible with a variety of downstream assays. We complement this with an optimized guide RNA scaffold that significantly enhances CRISPRa functionality. Finally, we describe a synthetic guide RNA tool set that enables transient, population-wide gene activation when used with the self-selecting CRISPRa system. Taken together, this versatile platform greatly enhances the potential for CRISPRa across a wide variety of cellular contexts.

Long-term survival after immunotherapy and targeted therapy without chemotherapy in an elderly patient with HER2-positive gastroesophageal junction cancer: A case report

A 74-yr-old man underwent thoracic laparoscopy combined with radical gastrectomy, and the postoperative pathological diagnosis was esophageal and gastric cardia cancer pT3N1M0, pStage IIB. Immunohistochemical staining for HER2 (3+) and PD-L1 (<5%) was positive. Adjuvant chemotherapy was not performed because the patient developed severe thrombocytopenia (platelet counts <30 × 10⁹/L), which was never cured throughout the reporting period. At 10.7 months post-surgery, he suffered metastases in multiple organs, including the peritoneum, liver, lung, and bone. Following two cycles of first-line trastuzumab and pembrolizumab (200 mg), he developed immune-related myositis (G2), myocarditis (G2), and hepatitis (G1). Therefore, pembrolizumab was discontinued. Trastuzumab was administered as a monotherapy; meanwhile, adoptive cytokine-induced killer (CIK) cell infusions were initiated. Eight months after the initial immunotherapy, a solitary brain metastasis was detected, and the patient underwent CyberKnife radiosurgery. For second-line therapy, adoptive CIK cell immunotherapy plus trastuzumab was still used. At the time of reporting, the patient had achieved a complete response (CR) in the brain and liver and a partial response (PR) in the ilium, and he had been followed-up for 36.6 months, much longer than the median survival time for patients with advanced GEJ cancer. We suggest that HER2-targeted therapy and immunotherapy with pembrolizumab or CIK adoptive cell infusions prolonged the overall survival of an elderly patient with HER2-positive GEJ cancer with multiple metastases.

Enhanced Inhibitory Effect of DC-CIK Cells on Lung Adenocarcinoma via Anti-Tim-3 Antibody and Antiprogrammed Cell Death-1 Antibody and Possible Mechanism

Objective

To investigate the effect and mechanism of blocking the signaling pathways of the T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) and programmed death protein 1 (PD-1) in dendritic cell-cytokine induced killer (DC-CIK) cells on human lung adenocarcinoma A549 cells.

Methods

Peripheral blood mononuclear cells (PBMCs) were isolated and induced into mature DC-CIK cells by cytokines in vitro. After blocking the Tim-3 and PD-1 signaling transduction pathways with anti-Tim-3 and anti-PD-1 antibodies, DC-CIK cells were coincubated with A549 cells. The killing effect of DC-CIK cells against A549 cells was measured by a CCK-8 assay. The impact of DC-CIK cells on the invasion and migration ability of A549 cells was detected by the Transwell test. The apoptosis rate of DC-CIK cells and the ratio of CD4⁺, CD8⁺, and DC-CIK cell subsets were determined by flow cytometry. The cell proliferation of DC-CIK was detected by the CCK-8 assay.

Results

The antibodies of anti-Tim-3 antibody and anti-PD-1 could block Tim-3⁺ and PD-1⁺ DC-CIK cells and could significantly increase the killing effect of DC-CIK cells on A549 cells. The number of A549 cells under the microporous membrane of the Transwell chamber was reduced considerably in invasion and migration tests. Anti-Tim-3 and anti-PD-1 antibodies significantly reduced apoptosis of DC-CIK cells. No significant differences were observed in the ratios of CD4⁺ and CD8⁺ DC-CIK cell subsets or the proliferation capacity of DC-CIK cells in each group.

Conclusion

Blocking the Tim-3 and PD-1 signaling pathways of DC-CIK cells with antibodies can enhance the killing ability of DC-CIK cells in A549 cells and significantly suppress the invasion and migration ability of A549 cells. The potential mechanism may be related to reduced apoptosis of DC-CIK cells.

Complete Response to PD-1 Inhibitor in Primary Hepatocellular Carcinoma Patients Post-Progression on Bi-Specific Antibody Conjugated CIK Cell Treatment: A Report of Two Cases

Background

Programmed death receptor-1 (PD-1) immune checkpoint inhibitors (ICIs) have produced encouraging results in hepatocellular carcinoma (HCC) patients. Cytokine-induced killer (CIK) cells treatment can specifically identify tumor-associated antigens and has encouraging preliminary efficacy for HCC. This study reported two cases of HCC patients achieved complete response (CR) by anti-PD-1 antibody therapy post-progression on bi-specific antibody conjugated CIK immunotherapy.

Case Presentation

Case one, a 75-year-old male, was diagnosed with the intrahepatic cholangiocarcinoma (ICC) in October 2017. After interventional, CIK, ablation and other comprehensive therapy, ICC was gradually cured. When new occurrence of HCC, he was treated with anti-PD-1 antibody therapy and achieved CR. Case two, a 65-year-old female, was diagnosed with HCC in July 2016. After progression on several ablation treatments, she received 8 cycles of CIK treatment and achieved stable disease (SD). After disease progressed on CIK treatment, she received 4 cycles of anti-PD-1 antibody therapy, finally achieved CR.

Conclusion

Anti-PD-1 antibody therapy after prior progression on bi-specific antibody conjugated CIK immunotherapy may be efficacy and safety for HCC patients.

NKG2D Engagement Alone Is Sufficient to Activate Cytokine-Induced Killer Cells While 2B4 Only Provides Limited Coactivation

Cytokine-induced killer (CIK) cells are an ex vivo expanded heterogeneous cell population with an enriched NK-T phenotype (CD3+CD56+). Due to the convenient and relatively inexpensive expansion capability, together with low incidence of graft versus host disease (GVHD) in allogeneic cancer patients, CIK cells are a promising candidate for immunotherapy. It is well known that natural killer group 2D (NKG2D) plays an important role in CIK cell-mediated antitumor activity; however, it remains unclear whether its engagement alone is sufficient or if it requires additional co-stimulatory signals to activate the CIK cells. Likewise, the role of 2B4 has not yet been identified in CIK cells. Herein, we investigated the individual and cumulative contribution of NKG2D and 2B4 in the activation of CIK cells. Our analysis suggests that (a) NKG2D (not 2B4) is implicated in CIK cell (especially CD3+CD56+ subset)-mediated cytotoxicity, IFN-γ secretion, E/T conjugate formation, and degranulation; (b) NKG2D alone is adequate enough to induce degranulation, IFN-γ secretion, and LFA-1 activation in CIK cells, while 2B4 only provides limited synergy with NKG2D (e.g., in LFA-1 activation); and (c) NKG2D was unable to costimulate CD3. Collectively, we conclude that NKG2D engagement alone suffices to activate CIK cells, thereby strengthening the idea that targeting the NKG2D axis is a promising approach to improve CIK cell therapy for cancer patients. Furthermore, CIK cells exhibit similarities to classical invariant natural killer (iNKT) cells with deficiencies in 2B4 stimulation and in the costimulation of CD3 with NKG2D. In addition, based on the current data, the divergence in receptor function between CIK cells and NK (or T) cells can be assumed, pointing to the possibility that molecular modifications (e.g., using chimeric antigen receptor technology) on CIK cells may need to be customized and optimized to maximize their functional potential.

Adaptive NK Cell Therapy Modulated by Anti-PD-1 Antibody in Gastric Cancer Model

Recently, adaptive NK cell therapy has become a promising treatment but has limited efficacy as a monotherapy. The identification of immune checkpoint inhibitor (ICI) molecules has opened a new horizon of immunotherapy. Herein, we aimed to demonstrate the cytotoxic effects of a polytherapy consisting of ex vivo expanded IL-2-activated NK cells combined with human anti-PD-1 antibody as an important checkpoint molecule in a xenograft gastric cancer mouse model. EBV-LCL cell is used as a feeder to promote NK cell proliferation with a purity of 93.4%. Mice (NOG, female, 6–8 weeks old) with xenograft gastric tumors were treated with PBS, ex vivo IL-2-activated NK cells, IL-2-activated NK cell along with human anti-PD-1 (Nivolumab), and IL-2-activated pretreated NK cells with anti-PD-1 antibody. The cytotoxicity of ex vivo expanded NK cells against MKN-45 cells was assessed by a lactate dehydrogenase (LDH) assay. Tumor volume was evaluated for morphometric properties, and tumor-infiltrating NK cells were assessed by immunohistochemistry (IHC) and quantified by flow cytometry. Pathologic responses were considered by H and E staining. Ex vivo LDH evaluation showed the cytotoxic potential of treated NK cells against gastric cancer cell line. We indicated that the adoptive transfer of ex vivo IL-2-activated NK cells combined with anti-PD-1 resulted in tumor growth inhibition in a xenograft gastric cancer model. Mitotic count was significantly decreased (*p < 0.05), and the tumor was associated with improved infiltration of NK cells in the NK-anti-PD-1 pretreated group (*p < 0.05). In conclusion, the combination approach of activated NK cells and anti-PD-1 therapy results in tumor growth inhibition, accompanied by tumor immune cell infiltration in the gastric tumor model.

PD-1 blockade enhances cytokine-induced killer cell-mediated cytotoxicity in B-cell non-Hodgkin lymphoma cell lines

The clinical utility of immune checkpoint inhibitors, such as programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) inhibitors used alone or in combination with other therapies, is currently gaining attention. In this particular scenario, the inclusion of cytokine-induced killer (CIK) cells has proven to be a novel therapeutic approach. CIK cells have shown anticancer activity in various hematopoietic malignancies, but their defined cytotoxicity in B-cell non-Hodgkin lymphoma (B-NHL) remains to be fully elucidated. The present study investigated the role of PD-1/PD-L1 blockades on the cytotoxic efficacy of CIK cells primarily in B-NHL cell lines. The current analysis revealed that CIK cells prompted cytotoxicity against B-NHL cell lines (DAUDI and SU-DHL-4), and a significant increase in PD-L1 expression was observed when CIK cells were co-cultured with B-NHL cells. Additionally, a combination of PD-1 and PD-L1 antibodies with CIK cells significantly decreased cell viability only in DAUDI cells. Furthermore, IFN-γ elevation was observed in both cell lines treated with CIK alone or with PD-1 antibody, but this tendency was not observed for PD-L1. Since PD-1 can suppress immune inactivation, whereas CD40L can promote it, the effects of CD40L blockade were also examined; however, no significant changes in cell viability were observed. Overall, the present in vitro data suggested that CIK cells exerted a cytotoxic function in B-NHL cells, and a combination of PD-1 inhibitors with CIK cells may provide a potential therapeutic option for this type of lymphoma. Nevertheless, in vivo experiments are warranted to undermine the extent to which PD-1 inhibitors may be used to enhance the antitumor activity of CIK cells in B-NHL.

PD-1 Immune Checkpoint Inhibitor Therapy Malignant Tumor Based on Monotherapy and Combined Treatment Research

Recently, immunotherapy has become the fourth pillar of cancer treatment in addition to surgery therapy, chemotherapy, and radiation therapy. The inhibitors of programed cell death protein 1 (PD-1) and its ligand PD-L1 are the new stars in immunotherapy, as they can overcome tumor immunosuppression. However, the efficacy of PD-1 inhibitors still needs to be further developed for clinical treatment. Therefore, research into treatment with anti-PD-1 drugs has emerged as a new development field. This review provides novel insights into the role and mechanism of PD-1 combination anti-tumor therapy, thereby promoting its clinical application in anti-tumor immunotherapy.

The efficacy and safety of the combination of axitinib and pembrolizumab-activated autologous DC-CIK cell immunotherapy for patients with advanced renal cell carcinoma: a phase 2 study

Objectives

Although axitinib has achieved a preferable response rate for advanced renal cell carcinoma (RCC), patient survival remains unsatisfactory. In this study, we evaluated the efficacy and safety of a combination treatment of axitinib and a low dose of pembrolizumab‐activated autologous dendritic cells–co‐cultured cytokine‐induced killer cells in patients with advanced RCC.

Methods

All adult patients, including treatment‐naive or pretreated with VEGF‐targeted agents, were enrolled from May 2016 to March 2019. Patients received axitinib 5 mg twice daily and pembrolizumab‐activated dendritic cells–co‐cultured cytokine‐induced killer cells intravenously weekly for the first four cycles, every 2 weeks for the next four cycles, and every month thereafter.

Results

The 43 patients (22 untreated and 21 previously treated) showed a median progression‐free survival (mPFS) of 14.7 months (95% CI, 11.16–18.30). mPFS in treatment‐naive patients was 18.2 months, as compared with 14.4 months in pretreated patients (log‐rank P‐value = 0.07). Overall response rates were 25.6% (95% CI, 13.5–41.2%). Grade 3 or higher adverse events occurred in 5% of patients included hypertension (11.6%) and palmar‐plantar erythrodysesthesia (7.0%). Peripheral blood lymphocyte immunophenotype and serum cytokine profile analyses demonstrated increased antitumor immunity after combination treatment particularly in patients with a long‐term survival benefit, while those with a minimal survival benefit demonstrated an elevated proportion of peripheral CD8⁺TIM3⁺ T cells and lower serum‐level immunostimulatory cytokine profile.

Conclusions

The combination therapy was active and well tolerated for treatment of advanced RCC, either as first‐ or second‐line treatment following other targeted agents. Changes in immunophenotype and serum cytokine profile may be used as prognostic biomarkers.

Clinicopathological and prognostic significance of programmed death ligant-1 expression in gastric cancer: a meta-analysis

Background

Gastric cancer (GC) is a common malignant tumor with a high incidence in China. The use of immune checkpoint inhibitors has become the focus of tumor immunotherapy in recent years. This study was to investigate the clinicopathological and prognostic significance of programmed death ligant-1 (PD-L1) expression in GC.

Methods

We searched the PubMed, ScienceNet, EMbase, CNKI, and Wanfang databases for retrospective cohort studies on the clinicopathology and prognosis of PD-L1 expression in GC published between January 2010 and April 2020. The literature was first selected to extract data according to the inclusion and exclusion criteria, then a meta-analysis performed using Stata15.0 software. Publication bias and sensitivity analysis were carried out for the included studies.

Results

A total of 3,218 patients in 15 studies were included in the meta-analysis. The positive expression of PD-L1 was related to a decrease in the 3-year survival rate (HR =1.32, 95% CI: 1.02-1.49, P=0.028) and 5-year survival rate (HR =1.39, 95% CI: 1.14-1.69, P=0.001). The difference in PD-L1 expression was related to lymph node metastasis (OR =1.73, 95% CI: 1.18-2.54, P<0.001), but not to tumor stage (OR =1.28, 95% CI: 0.81-2.02, P=0.292).

Conclusions

The results show that PD-L1 is related to the prognosis of GC. Its high expression decreases the 3- and 5-year survival rates and promotes lymph node metastasis, but does not reflect tumor stage. The results may provide a theoretical basis for the choice of clinical immunotherapy in GC patients.

MiR-374b increases the CIK expression and mediates biological function changes in cervical cancer cells by targeting the PD-1/PD-L1 signaling pathway

OBJECTIVE

To investigate the role of miR-374b in medicating biological function changes in cervical cancer cells by increasing the cytokine-induced killer (CIK) expression.

METHODS

Venous blood of 62 cervical cancer patients and 58 healthy individuals including Human cervical cancer cell line (HeLa) and normal human uterine smooth muscle cells (HUSMC) were tested for expression of miR-374b, PD-1, and PD-L1. sh-PD-1, si-PD-1, NC, miR-374b-inhibitor, and miR-374b-mimics were transfected into HeLa cells, and expression of miR-374b, PD-1, and PD-L1 was determined by a qRT-PCR assay, and the proliferation and apoptosis of the cells were detected using a MTT assay and flow cytometry, respectively.

RESULTS

PD-1 was highly expressed in cervical cancer, while miR-374b is lowly expressed in it, and the area-under-the-curve (AUC) of both PD-1 and miR-374b was larger than 0.8. The dual luciferase reporter assay confirmed relationship between PD-1 and miR-374b. Expression of PD-1 in HeLa cells was significantly down-regulated after transfection of miR-374b-mimics. Compared with the CIK + NC group, the CIK + miR-374b-mimics group and the CIK + siRNA-PD-1 group showed a significant decrease in the relative mRNA expression of PD-1, compared with other group showed significantly lowered activity of HeLa cells, and the two groups showed significantly reduced tumor volume.

CONCLUSION

MiR-374b increases the CIK expression and mediates biological function changes in cervical cancer cells by targeting the PD-1/PD-L1 signaling pathway, so it is expected to be a potential therapeutic target for cervical cancer.

Overview on new progress of hereditary diffuse gastric cancer with CDH1 variants

Hereditary diffuse gastric cancer (HDGC), comprising 1%-3% of gastric malignances, has been associated with CDH1 variants. Accumulating evidence has demonstrated more than 100 germline CDH1 variant types. E-cadherin encoded by the CDH1 gene serves as a tumor suppressor protein. CDH1 promoter hypermethylation and other molecular mechanisms resulting in E-cadherin dysfunction are involved in the tumorigenesis of HDGC. Histopathology exhibits characteristic signet ring cells, and immunohistochemical staining may show negativity for E-cadherin and other signaling proteins. Early HDGC is difficult to detect by endoscopy due to the development of lesions beneath the mucosa. Prophylactic gastrectomy is the most recommended treatment for pathogenic CDH1 variant carriers. Recent studies have promoted the progression of promising molecular-targeted therapies and management strategies. This review summarizes recent advances in CDH1 variant types, tumorigenesis mechanisms, diagnosis, and therapy, as well as clinical implications for future gene therapies.

Cytokines as potential combination agents with PD-1/PD-L1 blockade for cancer treatment

Immunotherapy has caused a paradigm shift in the treatment of several malignancies, particularly the blockade of programmed death-1 (PD-1) and its specific receptor/ligand PD-L1 that have revolutionized the treatment of a variety of malignancies, but significant durable responses only occur in a small percentage of patients, and other patients failed to respond to the treatment. Even those who initially respond can ultimately relapse despite maintenance treatment, there is considerable potential for synergistic combinations of immunotherapy and chemotherapy agents with immune checkpoint inhibitors into conventional cancer treatments. The clinical experience in the use of cytokines in the clinical setting indicated the efficiency of cytokine therapy in cancer immunotherapy. Combinational approaches to enhancing PD-L1/PD-1 pathways blockade efficacy with several cytokines such as interleukin (IL)-2, IL-15, IL-21, IL-12, IL-10, and interferon-α (IFN-α) may result in additional benefits. In this review, the current state of knowledge about PD-1/PD-L1 inhibitors, the date in the literature to ascertain the combination of anti-PD-1/PD-L1 antibodies with cytokines is discussed. Finally, it is noteworthy that novel therapeutic approaches based on the efficient combination of recombinant cytokines with the PD-L1/PD-1 blockade therapy can enhance antitumor immune responses against various malignancies.

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.

Clinical Trials with Combination of Cytokine-Induced Killer Cells and Dendritic Cells for Cancer Therapy

Adoptive cellular immunotherapy (ACI) is a promising treatment for a number of cancers. Cytokine-induced killer cells (CIKs) are considered to be major cytotoxic immunologic effector cells. Usually cancer cells are able to suppress antitumor responses by secreting immunosuppressive factors. CIKs have significant antitumor activity and are capable of eradicating tumors with few side effects. They are a very encouraging cell population used against hematological and solid tumors, with an inexpensive expansion protocol which could yield to superior clinical outcome in clinical trials employing adoptive cellular therapy combination. In the last decade, clinical protocols have been modified by enriching lymphocytes with CIK cells. They are a subpopulation of lymphocytes characterized by the expression of CD3+ and CD56+ wich are surface markers common to T lymphocytes and natural killer NK cells. CIK cells are mainly used in two diseases: in hematological patients who suffer relapse after allogeneic transplantation and in patients with hepatic carcinoma after surgical ablation to eliminate residual tumor cells. Dendritic cells DCs could play a pivotal role in enhancing the antitumor efficacy of CIKs.

Targeting late-stage non-small cell lung cancer with a combination of DNT cellular therapy and PD-1 checkpoint blockade

Background

Though immune checkpoint blockade (ICB) against PD-1 has shown success in the treatment of lung cancer, not all patients respond. We have previously shown that adoptive transfer of double negative T (DNT) cells expanded from healthy donors can target leukemia but their role in treating established lung cancer is not clear. Here we explore the role of human DNT cells in targeting late-stage established lung cancer either alone or in combination with Nivolumab (anti-PD-1 antibody) and describe underlying mechanisms.

Methods

DNT cells from resected lung cancer tissue of patients were analyzed by flow cytometry to determine their infiltration and PD-1 expression. Expansion capacity and anti-tumor function of lung cancer patient and healthy donor DNT cells were compared. Late-stage lung cancer xenograft models were developed to determine the anti-tumor effect of DNT cells alone or in combination with anti-PD-1 antibody, and the level of tumor-infiltrating DNT cells was quantified by histology and characterized by flow cytometry.

Results

Patient-derived tumor infiltrating lymphocytes contained a lower frequency of DNT cells with a higher expression of PD-1 relative to normal lung tissue. Ex vivo expanded patient- and healthy donor-derived DNT cells showed similar levels of cytotoxicity against lung cancer cells in vitro. Healthy donor-derived DNT cells significantly inhibited the growth of late-stage lung cancer xenografts, which was further augmented by anti-PD-1 through increased DNT cell tumor infiltration.

Conclusion

This study supports the use of DNT cells for adoptive cellular therapy against lung cancer either alone or in combination with anti-PD-1.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1126-y) contains supplementary material, which is available to authorized users.

Promising immunotherapy: Highlighting cytokine-induced killer cells

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Efficacy and safety of apatinib combined with chemotherapy for the treatment of advanced gastric cancer in the Chinese population: a systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the efficacy and safety of the combination of apatinib targeted therapy and chemotherapy (CT) in the treatment of patients with advanced gastric cancer (GC).

MATERIALS AND METHODS

Clinical trials were extracted from PubMed, the Cochrane Library, Web of Science, EMBASE, CNKI, and the Wanfang database. Outcome measures, including therapeutic efficacy, quality of life (QOL), and adverse events, were extracted and evaluated.

RESULTS

Nineteen trials, including 1,256 advanced GC patients, were included. The results indicated that, compared with CT alone, the combination of apatinib targeted therapy with CT significantly improved the patients' complete response rate (OR=1.85, 95% CI=1.04-3.28, P=0.04), partial response rate (OR=2.19, 95% CI=1.71-2.80, P<0.00001), overall response (OR=2.57, 95% CI=1.99-3.32, P<0.00001), and disease control rate (OR=3.46, 95% CI=2.57-4.66, P<0.00001). Moreover, the combined therapy exhibited advantages over CT alone in the patients' QOL including the QOL improved rate (OR=1.77, 95% CI=0.94-3.33, P=0.08) and the Karnofsky performance score (OR=1.77, 95% CI=0.94-3.33, P=0.08). The group that received the combined therapy had higher rates of hypertension (OR=5.75, 95% CI=2.22-14.92, P=0.0003), albuminuria (OR=15.42, 95% CI=5.39-44.10, P<0.00001), and hand-foot syndrome (OR=2.09, 95% CI=1.26-3.48, P=0.004), whereas analyses of other adverse events, such as leucopenia, thrombocytopenia, and neutropenia, did not reveal significant differences (P>0.05).

CONCLUSION

The combination of apatinib targeted therapy and CT is more effective for GC treatment than CT alone. However, this combined treatment could lead to greater rates of hypertension, albuminuria, and hand-foot syndrome. Therefore, the benefits and risks should be considered before treatment.

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

Purpose

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

Patients and methods

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

Results

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

Conclusion

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

Checkpoints and beyond - Immunotherapy in colorectal cancer

Immunotherapy is the latest revolution in cancer therapy. It continues to show impressive results in malignancies like melanoma and others. At least so far, effects are modest in colorectal cancer (CRC) and only a subset of patients benefits from already approved checkpoint inhibitors. In this review, we discuss major hurdles of immunotherapy like the immunosuppressive niche and low immunogenicity of CRC next to current achievements of checkpoint inhibitors, interleukin treatment and adoptive cell transfer (dendritic cells/cytokine induced killer cells, tumor infiltrating lymphocytes, chimeric antigen receptor cells, T cell receptor transfer) in pre-clinical models and clinical trials. We intensively examine approaches to overcome low immunogenicity by combination of different therapies and address future strategies of therapy as well as the need of predictive factors in this emerging field of precision medicine.

A prognosis and impact factor analysis of DC-CIK cell therapy for patients with hepatocellular carcinoma undergoing postoperative TACE

Dendritic cell-cytokine-induced killer (DC-CIK) cell therapy has been experimentally implemented for enhancing anti-tumoral immunity in patients with hepatocellular carcinoma (HCC) undergoing postoperative transcatheter arterial chemoembolization (POTACE). We performed a retrospective study to evaluate the clinical efficacies of DC-CIK cell therapy and its correlations with several immune factors of the primary tumors. The overall survival time of HCC patients with HBV infection in the study group (POTACE plus DC-CIK cell therapy) was significantly longer than that of the control group (POTACE alone). The expression level of PD-L1 but not the tumor-infiltrated CD8 and CD4 T cells in the tumor tissues showed significant negative correlations with relapse-free survival (RFS) and overall survival (OS), which was also an independent prognostic factor for the five-years' suvival of patients with HCC receiving POTACE treatment. Furthermore, our study validated that PD-L1 expression was significantly inversely correlated with the survival time of HCC patients receiving POTACE plus DC-CIK cell therapy treatment. More importantly, DC-CIK cell therapy provided the best clinical benefits to HCC patients with the low PD-L1 expression receiving POTACE, which indicate that PD-L1 expression level can serve as a pivotal predictor for the therapeutic efficacy of DC-CIK cell therapy for HCC patients receiving POTACE treatment.

Safety and activity of PD-1 blockade-activated DC-CIK cells in patients with advanced solid tumors

Cytokine-induced killer (CIK) cells that are stimulated using mature dendritic cells (DCs), referred to as (DC-CIK cells) exhibit superior anti-tumor potency. Anti-programmed death-1 (PD-1) antibodies reinvigorate T cell-mediated antitumor immunity. This phase I study aimed to assess the safety and clinical activity of immunotherapy with PD-1 blockade (pembrolizumab)-activated autologous DC-CIK cells in patients with advanced solid tumors. Patients with selected types of advanced solid tumors received a single intravenous infusion of activated autologous DC-CIK cells weekly for the first month and every 2 weeks thereafter. The primary end points were safety and adverse event (AE) profiles. Antitumor responses, overall survival (OS), progression-free survival (PFS) and cytolytic activity were secondary end points. Treatment-related AEs occurred in 20/31 patients. Grade 3 or 4 toxicities, including fever and chills, were observed in two patients. All treatment-related AEs were reversible or controllable. The cytotoxicity of DC-CIK cells induced up-regulation of PD-L1 expression on autologous tumor cells. When activated using pembrolizumab ex vivo, DC-CIK cells exerted superior antitumor properties and elevated IFN-γ secretion. Objective responses (complete or partial responses) were observed in 7 of the 31patients.These responses were durable, with 6 of 7 responses lasting more than 5 months. The overall disease control rate in the patients was 64.5%. At the time of this report, the median OS and PFS were 270 and 162 days, respectively. In conclusions, treatment with pembrolizumab-activated autologous DC-CIK cells was safe and exerted encouraging antitumor activity in advanced solid tumors. A larger phase II trial is warranted.

89Zr-labeled nivolumab for imaging of T-cell infiltration in a humanized murine model of lung cancer

PURPOSE

Nivolumab is a human monoclonal antibody specific for programmed cell death-1 (PD-1), a negative regulator of T-cell activation and response. Acting as an immune checkpoint inhibitor, nivolumab binds to PD-1 expressed on the surface of many immune cells and prevents ligation by its natural ligands. Nivolumab is only effective in a subset of patients, and there is limited evidence supporting its use for diagnostic, monitoring, or stratification purposes.

METHODS

89Zr-Df-nivolumab was synthesized to map the biodistribution of PD-1-expressing tumor infiltrating T-cells in vivo using a humanized murine model of lung cancer. The tracer was developed by radiolabeling the antibody with the positron emitter zirconium-89 (89Zr). Imaging results were validated by ex vivo biodistribution studies, and PD-1 expression was validated by immunohistochemistry. Data obtained from PET imaging were used to determine human dosimetry estimations.

RESULTS

The tracer showed elevated binding to stimulated PD-1 expressing T-cells in vitro and in vivo. PET imaging of 89Zr-Df-nivolumab allowed for clear delineation of subcutaneous tumors through targeting of localized activated T-cells expressing PD-1 in the tumors and salivary glands of humanized A549 tumor-bearing mice. In addition to tumor uptake, salivary and lacrimal gland infiltration of T-cells was noticeably visible and confirmed via histological analysis.

CONCLUSIONS

These data support our claim that PD-1-targeted agents allow for tumor imaging in vivo, which may assist in the design and development of new immunotherapies. In the future, noninvasive imaging of immunotherapy biomarkers may assist in disease diagnostics, disease monitoring, and patient stratification.

MicroRNA-421 regulated by HIF-1α promotes metastasis, inhibits apoptosis, and induces cisplatin resistance by targeting E-cadherin and caspase-3 in gastric cancer

Hypoxia and dysregulation of microRNAs (miRNAs) have been identified as crucial factors in carcinogenesis. However, the potential mechanisms of HIF-1α and miR-421 in gastric cancer have not been well elucidated. In this study, we found that miR-421 was up-regulated by HIF-1α. Overexpression of miR-421 promoted metastasis, inhibited apoptosis, and induced cisplatin resistance in gastric cancer in vivo and in vitro. E-cadherin and caspase-3 were identified as targets of miR-421. Besides, relative mRNA expression of miR-421 was significantly increased in gastric cancer tumor tissues compared with non-tumor tissues in a cohort of gastric cancer specimens (n=107). The expression of miR-421 was higher in advanced gastric cancers compared with localized ones. Moreover, Kaplan–Meier analysis illustrated that those patients with low levels of miR-421 had a significant longer overall survival (p = 0.006) and time to relapse (p = 0.007). Therefore, miR-421 could serve as an important prognostic marker and a potential molecular target for therapy in gastric cancer.

CD4+T cell specific B7-H1 selectively inhibits proliferation of naïve T cells and Th17 differentiation in experimental autoimmune encephalomyelitis

It is widely acknowledged that interleukin 17-producing T helper (Th17) cells are critically participant in the pathogenesis of multiple sclerosis. In the current study, we identified that the expression of CD4⁺T cells specific co-inhibitory molecule B7-homologue 1(B7-H1) in spleenocytes and mononuclear cells isolated from brains and spinal cord were positive correlated with Th1 and Th17 cells generation and disease severity in experimental autoimmune encephalomyelitis (EAE). Furthermore, B7-H1 transgenic mice developed milder EAE symptoms and fewer Th17 cells than B7-H1 wild type mice. We also found the proliferation of naïve CD4⁺CD62⁺T cells isolated from B7-H1 transgenic mice was inhibited. And naïve T cells isolated from B7-H1 transgenic mice produced fewer Th17 cells than WT mice in Th17-polarizing conditions, but the Th1, Th2, and inducible Treg differentiation were the similar in naïve T cells isolated from B7-H1 transgenic mice and WT mice. In conclusion, our study show CD4⁺T cells specific B7-H1 is a slective inhibitor in proliferation of naïve T cells, Th17 differentiation and pathogenesis of multiple sclerosis.

A novel mimovirus encoding ChgA10-19 peptide with PD-L1 induces T cell tolerance and ameliorates the severity of diabetes

Related studies demonstrate that type 1 diabetes (T1D) is caused by β-cell antigen specific autoreactive CD8+ T cells. ChgA has recently been identified as the autoantigen in NOD mice and T1D patients. Therefore, attenuating the activation of ChgA specific CD8+ T cells might be a promising target for T1D therapy. The negative co-stimulatory PD-L1 inhibits T cell mediated alloimmunity and induces tolerance. In this experiment, a novel mimovirus encoding ChgA_10-19 peptide with PD-L1 was constructed. The NOD.β2m null HHD mice were administrated with mimovirus transduced DCs. After immunization, the activation and proliferation of CD8+ T cells were detected, diabetes incidence and pancreatic tissue destruction were also analyzed. The results demonstrated that transduced DCs attenuated CD8+ T cell activation and proliferation. In addition, transduced DCs inhibited CD8+ T response to ChgA stimulation, and ameliorated the severity of diabetes. These data suggested that mimovirus transduced DCs might provide novel clues for T1D therapy.

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.

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.

Impact of Metabolism on T-Cell Differentiation and Function and Cross Talk with Tumor Microenvironment

The immune system and metabolism are highly integrated and multilevel interactions between metabolic system and T lymphocyte signaling and fate exist. Accumulating evidence indicates that the regulation of nutrient uptake and utilization in T cells is critically important for the control of their differentiation and manipulating metabolic pathways in these cells can shape their function and survival. This review will discuss some potential cell metabolism pathways involved in shaping T lymphocyte function and differentiation. It will also describe show subsets of T cells have specific metabolic requirements and signaling pathways that contribute to their respective function. Examples showing the apparent similarity between cancer cell metabolism and T cells during activation are illustrated and finally some mechanisms being used by tumor microenvironment to orchestrate T-cell metabolic dysregulation and the subsequent emergence of immune suppression are discussed. We believe that targeting T-cell metabolism may provide an additional opportunity to manipulate T-cell function in the development of novel therapeutics.

Knockdown of PD-L1 in Human Gastric Cancer Cells Inhibits Tumor Progression and Improves the Cytotoxic Sensitivity to CIK Therapy

Background/Abstract: PD-L1 has been an important target of cancer immunotherapy. We have showed that in human gastric cancer tissues, over-expression of PD-L1 was significantly associated with cancer progression and patients' postoperative prognoses. However, as of now, how PD-L1 regulates the biological function of gastric cancer cells still remains elusive.

METHODS

We constructed the stable PD-L1 knockdown expression gastric cancer cell lines by using RNAi method, and further investigated the changes of biological functions including cell viability, migration, invasion, cell cycle, apoptosis, tumorigenicity in vivo, and the cytotoxic sensitivity to CIK therapy, in contrast to the control cells.

RESULTS

In the current study, we demonstrated that the knockdown of PD-L1 expression in human gastric cancer cells could significantly suppress the cell proliferation, migration, invasion, apoptosis, cell cycle, tumorigenicity in vivo and the cytotoxic sensitivity to CIK therapy.

CONCLUSION

Our results indicate that PD-L1 contributes towards transformation and progression of human gastric cancer cells, and its intervention could prove to be an important therapeutic strategy against gastric cancer.

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.

Oncolytic viruses against cancer stem cells: A promising approach for gastrointestinal cancer

Gastrointestinal cancer has been one of the five most commonly diagnosed and leading causes of cancer mortality over the past few decades. Great progress in traditional therapies has been made, which prolonged survival in patients with early cancer, yet tumor relapse and drug resistance still occurred, which is explained by the cancer stem cell (CSC) theory. Oncolytic virotherapy has attracted increasing interest in cancer because of its ability to infect and lyse CSCs. This paper reviews the basic knowledge, CSC markers and therapeutics of gastrointestinal cancer (liver, gastric, colon and pancreatic cancer), as well as research advances and possible molecular mechanisms of various oncolytic viruses against gastrointestinal CSCs. This paper also summarizes the existing obstacles to oncolytic virotherapy and proposes several alternative suggestions to overcome the therapeutic limitations.