Cellular immunotherapy using irradiated lung cancer cell vaccine co-expressing GM-CSF and IL-18 can induce significant antitumor effects

The Beneficial Effect of IL-12 and IL-18 Transduced Dendritic Cells Stimulated with Tumor Antigens on Generation of an Antitumor Response in a Mouse Colon Carcinoma Model

The main purpose of our study was to determine the effect of dendritic cell (DC) transduction with lentiviral vectors carrying sequences of il18 and/or il12 genes on the level of antitumor activity in vitro and in vivo. We examined the ability of DCs to migrate to the tumor-draining lymph nodes and infiltrate tumor tissue and to activate the local and systemic antitumor response. On the 15th day, DCs genetically modified for production of IL-12 and/or IL-18 were administered peritumorally to C57BL/6 female mice with established MC38 tumors. Lymphoid organs and tumor tissue were collected from mice on the 3rd, 5th, and 7th days after a single administration of DCs for further analysis. Administration of DCs transduced for production of IL-12 alone and in combination with IL-18 increased the inflow and activity of CD4+ and CD8+ T lymphocytes in the tumor microenvironment and tumor-draining lymph nodes. We also found that even a single administration of such modified DCs could trigger a systemic antitumor response as well as inhibit tumor growth. Application of the developed DC-based vaccines may exert a favorable impact on stimulation of an antitumor immune response, especially if these DC vaccines are administered repeatedly.

Circulating inflammatory cytokines and risk of five cancers: a Mendelian randomization analysis

BACKGROUND

Epidemiological and experimental evidence has linked chronic inflammation to cancer aetiology. It is unclear whether associations for specific inflammatory biomarkers are causal or due to bias. In order to examine whether altered genetically predicted concentration of circulating cytokines are associated with cancer development, we performed a two-sample Mendelian randomisation (MR) analysis.

METHODS

Up to 31,112 individuals of European descent were included in genome-wide association study (GWAS) meta-analyses of 47 circulating cytokines. Single nucleotide polymorphisms (SNPs) robustly associated with the cytokines, located in or close to their coding gene (cis), were used as instrumental variables. Inverse-variance weighted MR was used as the primary analysis, and the MR assumptions were evaluated in sensitivity and colocalization analyses and a false discovery rate (FDR) correction for multiple comparisons was applied. Corresponding germline GWAS summary data for five cancer outcomes (breast, endometrial, lung, ovarian, and prostate), and their subtypes were selected from the largest cancer-specific GWASs available (cases ranging from 12,906 for endometrial to 133,384 for breast cancer).

RESULTS

There was evidence of inverse associations of macrophage migration inhibitory factor with breast cancer (OR per SD = 0.88, 95% CI 0.83 to 0.94), interleukin-1 receptor antagonist with endometrial cancer (0.86, 0.80 to 0.93), interleukin-18 with lung cancer (0.87, 0.81 to 0.93), and beta-chemokine-RANTES with ovarian cancer (0.70, 0.57 to 0.85) and positive associations of monokine induced by gamma interferon with endometrial cancer (3.73, 1.86 to 7.47) and cutaneous T-cell attracting chemokine with lung cancer (1.51, 1.22 to 1.87). These associations were similar in sensitivity analyses and supported in colocalization analyses.

CONCLUSIONS

Our study adds to current knowledge on the role of specific inflammatory biomarker pathways in cancer aetiology. Further validation is needed to assess the potential of these cytokines as pharmacological or lifestyle targets for cancer prevention.

Mannan-BAM, TLR Ligands, Anti-CD40 Antibody (MBTA) Vaccine Immunotherapy: A Review of Current Evidence and Applications in Glioblastoma

The foundation of precision immunotherapy in oncology is rooted in computational biology and patient-derived sample sequencing to enrich for and target immunogenic epitopes. Discovery of these tumor-specific epitopes through tumor sequencing has revolutionized patient outcomes in many types of cancers that were previously untreatable. However, these therapeutic successes are far from universal, especially with cancers that carry high intratumoral heterogeneity such as glioblastoma (GBM). Herein, we present the technical aspects of Mannan-BAM, TLR Ligands, Anti-CD40 Antibody (MBTA) vaccine immunotherapy, an investigational therapeutic that potentially circumvents the need for in silico tumor-neoantigen enrichment. We then review the most promising GBM vaccination strategies to contextualize the MBTA vaccine. By reviewing current evidence using translational tumor models supporting MBTA vaccination, we evaluate the underlying principles that validate its clinical applicability. Finally, we showcase the translational potential of MBTA vaccination as a potential immunotherapy in GBM, along with established surgical and immunologic cancer treatment paradigms.

Pulmonary Complications of Immunotherapy

Immune checkpoint inhibitor (ICI) therapy represents a paradigm shift in the treatment of patients with locally advanced and metastatic lung cancer. Although immunotherapy generally has a more favorable safety profile when compared with chemotherapy, immune-related adverse events represent important, but incompletely understood, treatment-limiting complications associated with significant morbidity and mortality risk. Current guidelines for diagnosis and management are derived from consensus experience, highlighting that further prospective investigation in this area is needed. As ICI-related pneumonitis is a clinically and radiographically diverse toxidrome, clinical vigilance is important while treating patients with lung cancer.

Induction of Immune Response Against Metastatic Tumors via Vaccination of Mannan-BAM, TLR Ligands and Anti-CD40 Antibody (MBTA)

Emerging evidence is demonstrating the extent of T-cell infiltration within the tumor microenvironment has favorable prognostic and therapeutic implications. Hence, immunotherapeutic strategies that augment the T-cell signature of tumors hold promising therapeutic potential. Recently, immunotherapy based on intratumoral injection of mannan-BAM, toll-like receptor ligands and anti-CD40 antibody (MBTA) demonstrated promising potential to modulate the immune phenotype of injected tumors. The strategy promotes the phagocytosis of tumor cells to facilitate the recognition of tumor antigens and induce a tumor-specific adaptive immune response. Using a syngeneic colon carcinoma model, we demonstrate MBTA's potential to augment CD8⁺ T-cell tumor infiltrate when administered intratumorally or subcutaneously as part of a whole tumor cell vaccine. Both immunotherapeutic strategies proved effective at controlling tumor growth, prolonged survival and induced immunological memory against the parental cell line. Collectively, our investigation demonstrates MBTA's potential to trigger a potent anti-tumor immune response.

Effect of lentiviral vector-packaged interleukin-18 gene on the malignant behavior of lung cancer

Interleukin-18 (IL-18) is a multifunctional cytokine that exhibits antitumor, anti-infection and immunoregulatory functions. This study aimed to investigate the effects of lentiviral vector-packaged interleukin (IL)-18 gene on the malignant behavior of lung cancer and the potential underlying molecular mechanism of IL-18 anticancer activity. Human lung adenocarcinoma A549 cells transfected with human IL-18 gene-containing lentiviral expression vector were the IL-18 intervention group (group A), cells transfected with the empty lentiviral expression vector were empty vector group (group B), and cells without any intervention were the blank control group (group C). Reverse transcription-quantitative PCR and western blotting were used to determine IL-18 mRNA and protein expression levels. Cell Counting Kit-8, colony-formation, flow cytometry, invasion and wound-healing assays were used to evaluate the malignant behavior of A549 cells transfected with the IL-18 lentiviral vector. The expression levels of the T helper (Th)1 cell cytokine interferon-γ (IFN-γ) and the Th2 cell cytokine IL-4 were tested by ELISA, and western blotting was used to test the expressing of nuclear factor κB (NF-κB). The results demonstrated that IL-18 mRNA and protein expression levels in group A were significantly increased compared with groups B and C; the expression levels of IFN-γ in group A were higher and the expression levels of IL-4 in group A were lower compared with those in groups B and C; and the expression of NF-κB was increased in the cytoplasm and decreased in the nucleus in group A compared with groups B and C. The data indicated that, compared with the control groups, the IL-18 gene lentiviral expression vector increased the expression of IL-18, diminished A549 cell proliferative ability, enhanced apoptosis, decreased the invasive and metastatic capacities of the cells, promoted the secretion of IFN-γ, decreased the production of IL-4, reversed the imbalance of Th1/Th2 cell subsets and inhibited the nuclear activation of NF-κB, which collectively present an anti-lung cancer mechanism and deserve further study.

Overview of Current Immunotherapies Targeting Mutated KRAS Cancers

The occurrence of somatic substitution mutations of the KRAS proto-oncogene is highly prevalent in certain cancer types, which often leads to constant activation of proliferative pathways and subsequent neoplastic transformation. It is often seen as a gateway mutation in carcinogenesis and has been commonly deemed as a predictive biomarker for poor prognosis and relapse when conventional chemotherapeutics are employed. Additionally, its mutational status also renders EGFR targeted therapies ineffective owing to its downstream location. Efforts to discover new approaches targeting this menacing culprit have been ongoing for years without much success, and with incidences of KRAS positive cancer patients being on the rise, researchers are now turning towards immunotherapies as the way forward. In this scoping review, recent immunotherapeutic developments and advances in both preclinical and clinical studies targeting K-ras directly or indirectly via its downstream signal transduction machinery will be discussed. Additionally, some of the challenges and limitations of various K-ras targeting immunotherapeutic approaches such as vaccines, adoptive T cell therapies, and checkpoint inhibitors against KRAS positive cancers will be deliberated.

Danggui Buxue Decoction Sensitizes the Response of Non-Small-Cell Lung Cancer to Gemcitabine via Regulating Deoxycytidine Kinase and P-glycoprotein

This study aimed to investigate whether the anti-tumor effect of gemcitabine (GEM) in non-small-cell lung cancer (NSCLC) treatment was affected by Danggui Buxue decoction (DBD), and explore the potential mechanisms. The combined use of GEM and DBD showed an enhanced tumor growth inhibition effect in a murine Lewis lung carcinoma (LLC) model. LC-MS/MS results showed that the pharmacokinetic behaviors of a GEM active metabolite, gemcitabine triphosphate (dFdCTP), were found to be altered remarkably in the peripheral blood mononuclear cells (PBMC) of DBD co-administration rats. In addition, after co-administration of DBD with GEM, Western Blot and qPCR results confirmed that the expression of deoxycytidine kinase (dCK) in tumor tissues of LLC-bearing mice were markedly increased. DBD co-administration also reversed the upregulation of P-glycoprotein (P-gp) in tumor tissues induced by GEM. Moreover, DBD could notably up-regulate the IL-12p70 and GM-CSF expression in mice serum, suggesting potential immunomodulatory activities in tumor-bearing mice. Meanwhile, DBD inhibited the P-gp efflux activity in A549 cells. Therefore, the regulation of dCK and P-gp played important roles in the alternation of GEM pharmacokinetics and the enhancement of the anti-tumor effect of GEM. DBD being a potential dCK promoter could work as an adjuvant agent to boost the anticancer effect of GEM.

Clearance of HBeAg and HBsAg of HBV in mice model by a recombinant HBV vaccine combined with GM-CSF and IFN-α as an effective therapeutic vaccine adjuvant

Chronic hepatitis B virus (CHB) infection is a significant public threat. Current interferon-α (IFN-α) based therapies and anti-viral drugs have failed to clear the infection in the majority of CHB patients and animal models. In our previous study, we established a combined protocol that employed a 3-day pretreatment with granulocyte-macrophage colony stimulating factor (GM-CSF) prior to a standard HBV vaccine. It achieved a 90% reduction of HBsAg level in the HBsAg transgenic mouse model. This protocol, while effective, remains too complex for clinical use. In this study, we formulated a new regimen by combining GM-CSF, IFN-α and a recombinant HBV vaccine (GM-CSF/IFN-α/VACCINE) into a single preparation and tested its efficacy in a HBV infection model. After four vaccinations, both serum HBeAg and HBsAg were cleared, accompanied by a 95% reduction of HBV⁺ hepatocytes and the presence of a large number of infiltrating CD8⁺ T cells in the liver. Mechanistically these robust responses were initiated by a vaccine-induced conversion of CCR2-dependent CD11b⁺Ly6C^hi monocytes into CD11b⁺CD11c⁺ DCs. This finding sheds light on the potential mechanism of action of the GM-CSF-based vaccine adjuvant and provides definable markers for clinical assessment during future testing of such highly potent vaccine protocols in HBV patients.

Human DKK1 and human HSP70 fusion DNA vaccine induces an effective anti-tumor efficacy in murine multiple myeloma

Dickkopf-1 (DKK1) is an ideal target for the immunotherapy of multiple myeloma. Heat Shock protein70 (HSP70) is a class of important molecular chaperone to promote antigen presentation. Homologous xenogeneic antigens can enhance immunogenicity and induce stronger anti-tumor immune response than that of allogeneic ones. Therefore, we constructed human DKK1 and human HSP70 DNA fusion vaccine (hDKK1-hHSP70), and then determined its anti-tumor immuno- genicity and anti-tumor effects on immunizing BALB/c mice already inoculated with NS-1 murine multiple myeloma cells in prophylactic and therapeutic models using cytotoxic T lymphocytes, enzyme-lined immunosorbent assay, flow cytometry, immunohistochemistry and Hochest staining. The side effects of vaccines were also monitored. We found that hDKK1-hHSP70 fusion vaccine could significantly inhibit tumor growth and prolonged the survival of the mice, whether prophylactic or therapeutic immunotherapy in vivo, by eliciting both humoral and cellular tumor-specific immune responses. A significant decrease of proliferation and increase of apoptosis were also observed in the tumor tissues injected with hDKK1-hHSP70 vaccine. These findings showed the xenogeneic homologous vaccination had stronger immunogenicity and minimal toxicity. Our study may provide an effective and safety immonutheraphy strategy for multiple myeloma.

IL-18 receptor marks functional CD8+ T cells in non-small cell lung cancer

IL-18 is an inflammasome-related cytokine, member of the IL-1 family, produced by a wide range of cells in response to signals by several pathogen- or damage-associated molecular patterns. It can be highly represented in tumor patients, but its relevance in human cancer development is not clear. In this study, we provide evidence that IL-18 is principally expressed in tumor cells and, in concert with other conventional Th1 cell-driven cytokines, has a pivotal role in establishing a pro-inflammatory milieu in the tumor microenvironment of human non-small cell lung cancer (NSCLC). Interestingly, the analysis of tumor-infiltrating CD8⁺ T cell populations showed that (i) the relative IL-18 receptor (IL-18R) is significantly more expressed by the minority of cells with a functional phenotype (T-bet⁺Eomes⁺), than by the majority of those with the dysfunctional phenotype T-bet^-Eomes⁺ generally resident within tumors; (ii) as a consequence, the former are significantly more responsive than the latter to IL-18 stimulus in terms of IFNγ production ex vivo; (iii) PD-1 expression does not discriminate these two populations. These data indicate that IL-18R may represent a biomarker of the minority of functional tumor-infiltrating CD8⁺ T cells in adenocarcinoma NSCLC patients. In addition, our results lead to envisage the possible therapeutic usage of IL-18 in NSCLC, even in combination with other checkpoint inhibitor approaches.

Oncolytic adenovirus expressing interleukin-18 improves antitumor activity of dacarbazine for malignant melanoma

Conditionally replicating adenoviruses have emerged as novel therapeutic agents for cancer. This study aimed to evaluate synergistic antitumor activity of replication-competent adenovirus armed with interleukin (IL)-18 (ZD55-IL-18) and dacarbazine (DTIC) against melanoma. Melanoma A375 cells or nude mouse tumor xenografts were treated with ZD55-IL-18 alone or together with DTIC. The results showed that ZD55-IL-18 competently replicated in A375 cells and expressed IL-18, and these were not affected by DTIC. ZD55-IL-18 enhanced the cytotoxicity of DTIC accompanied by increased apoptosis. Moreover, ZD55-IL-18 and DTIC synergistically inhibited the growth but promoted the apoptosis of A375 xenografts and inhibited vascular endothelial growth factor expression and lung metastasis in xenografts of nude mice. In conclusion, this is the first study to show synergistic anticancer activity of ZD55-IL-18 and DTIC for malignant melanoma. Our results provide evidence that chemo-gene-viro therapeutic approach has greater potential for malignant cancers than conventional chemotherapy or gene therapy.

Metronomic cyclophosphamide activation of anti-tumor immunity: tumor model, mouse host, and drug schedule dependence of gene responses and their upstream regulators

Background

Cyclophosphamide (CPA) can activate immunogenic tumor cell death, which induces immune-based tumor ablation and long-term anti-tumor immunity in a syngeneic C57BL/6 (B6) mouse GL261 glioma model when CPA is given on a 6-day repeating metronomic schedule (CPA/6d). In contrast, we find that two other syngeneic B6 mouse tumors, LLC lung carcinoma and B16F10 melanoma, do not exhibit these drug-induced immune responses despite their intrinsic sensitivity to CPA cytotoxicity.

Methods

To elucidate underlying mechanisms, we investigated gene expression and molecular pathway changes associated with the disparate immune responsiveness of these tumors to CPA/6d treatment.

Results

Global transcriptome analysis indicated substantial elevation of basal GL261 immune infiltration and strong CPA/6d activation of GL261 immune stimulatory pathways and their upstream regulators, but without preferential depletion of negative immune regulators compared to LLC and B16F10 tumors. In LLC tumors, where CPA/6d treatment is shown to be anti-angiogenic, CPA/6d suppressed VEGFA target genes and down regulated cell adhesion and leukocyte transendothelial migration genes. In GL261 tumors implanted in adaptive immune-deficient scid mice, where CPA/6d-induced GL261 regression is incomplete and late tumor growth rebound can occur, T cell receptor signaling and certain cytokine-cytokine receptor responses seen in B6 mice were deficient. Extending the CPA treatment interval from 6 to 9 days (CPA/9d) − which results in a strong but transient natural killer cell response followed by early tumor growth rebound − induced fewer cytokines and increased expression of drug metabolism genes.

Conclusions

These findings elucidate molecular response pathways activated by intermittent metronomic CPA treatment and identify deficiencies that characterize immune-unresponsive tumor models and drug schedules.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2597-2) contains supplementary material, which is available to authorized users.

The IL-17-Th1/Th17 pathway: an attractive target for lung cancer therapy?

INTRODUCTION

There is strong pharmaceutical development of agents targeting the IL-17-TH17 pathway for the treatment of psoriasis (Ps) and psoriatic arthritis (PsA). Lung cancer accounts for 28% of all cancer-related deaths worldwide, and roughly 80% of patients with newly-diagnosed non-small cell lung cancer (NSCLC) present with metastatic disease, with a poor prognosis of around 12 months. Therefore, there is a high unmet medical need for the development of new and potent systemic treatments in this deadly disease. The emergence of immunotherapies such as anti-PD-1 or anti-PDL1 as candidate therapies in non-small cell lung cancer (NSCLC) indicates that targeting critical immuno-modulatory cytokines including those within the IL-17-Th1/Th17 axis may have proven benefit in the treatment of lung cancer. Areas covered: In this review we describe the current evidence for aberrant IL-17-Th1/Th17 settings in cancer, particularly with regard to targeting this axis in NSCLC. We further discuss the current agents under pharmaceutical development which could potentially target this axis, and discuss the current limitations and areas of concern regarding the use of these in lung cancer. Expert opinion: Current evidence suggests that moving forward agents targeting the IL-17-Th1/Th17 pathway may have novel new oncoimmunology indications in the treatment paradigm for NSCLC.

Emerging nanotechnologies for cancer immunotherapy

Founded on the growing insight into the complex cancer-immune system interactions, adjuvant immunotherapies are rapidly emerging and being adapted for the treatment of various human malignancies. Immune checkpoint inhibitors, for example, have already shown clinical success. Nevertheless, many approaches are not optimized, require frequent administration, are associated with systemic toxicities and only show modest efficacy as monotherapies. Nanotechnology can potentially enhance the efficacy of such immunotherapies by improving the delivery, retention and release of immunostimulatory agents and biologicals in targeted cell populations and tissues. This review presents the current status and emerging trends in such nanotechnology-based cancer immunotherapies including the role of nanoparticles as carriers of immunomodulators, nanoparticles-based cancer vaccines, and depots for sustained immunostimulation. Also highlighted are key translational challenges and opportunities in this rapidly growing field.

The interleukin-18 gene promoter -607 A/C polymorphism contributes to non-small-cell lung cancer risk in a Chinese population

The purpose of the present study was to determine the relationship between interleukin-18 (IL-18) -607 A/C polymorphism and the risk of non-small-cell lung cancer (NSCLC) and its impact on the serum IL-18 level. The genotyping of IL-18 -607 A/C polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results showed that the AA/AC genotype distribution in NSCLC patients was significantly higher than that of healthy controls (P=0.02). However, no significant differences were found between the two subgroups when stratified by clinical characteristics. Furthermore, serum IL-18 levels were found to be significantly higher in the NSCLC patients than in the controls (P=0.01) as detected by enzyme-linked immunosorbent assay analysis. There was no correlation between serum IL-18 levels and different genotypes. In conclusion, these findings suggest that IL-18 -607 A/C polymorphism increases the risk of NSCLC in the Chinese population, and this polymorphism could not functionally affect the IL-18 levels.

IL-18 Is Involved in Eosinophil-Mediated Tumoricidal Activity against a Colon Carcinoma Cell Line by Upregulating LFA-1 and ICAM-1

Eosinophils are multifunctional leukocytes that are involved in innate and adaptive immune responses through the expression of various receptors and mediators. Previously, we showed that human eosinophils and T cells shared cytotoxic activities against tumor cells that involved the γ-δ TCR and cell-cell contact. In this study, we investigated the molecules involved in eosinophil-tumor cell interactions. Given the role of IL-18 in cell adhesion and in protecting against colon cancer, we evaluated its role in eosinophil-mediated cytotoxicity against Colo-205, a human colon carcinoma cell line. We found that human eosinophils exerted dose- and time-dependent tumoricidal activity against Colo-205 cells. Neutralization of IL-18 significantly reduced eosinophil-mediated Colo-205 apoptosis and inhibited cell-cell adhesion. Moreover, addition of rIL-18 led to upregulation of CD11a and ICAM-1 adhesion molecules, which were involved in the contact between eosinophils and Colo-205 cells. Our results indicated that IL-18 was involved in the eosinophil-mediated death of Colo-205 by facilitating contact between effector and target cells. These data underscored the involvement of an additional mediator in eosinophil-mediated antitumor cytotoxicity. Our findings support existing evidence that eosinophils could play a beneficial role in the context of colon cancer.

Development of Membrane-Bound GM-CSF and IL-18 as an Effective Tumor Vaccine

The development of effective adjuvant is the key factor to boost the immunogenicity of tumor cells as a tumor vaccine. In this study, we expressed membrane-bound granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-18 (IL-18) as adjuvants in tumor cells to stimulate immune response. B7 transmembrane domain fused GM-CSF and IL-18 was successfully expressed in the cell membrane and stimulated mouse splenocyte proliferation. Co-expression of GM-CSF and IL-18 reduced tumorigenesis (P<0.05) and enhanced tumor protective efficacy (P<0.05) significantly in comparison with GM-CSF alone. These results indicated that the combination of GM-CSF andIL-18 will enhance the immunogenicity of a cell-based anti-tumor vaccine. This membrane-bound approach can be applied to other cytokines for the development of novel vaccine strategies.

Impact of the immune system and immunotherapy in colorectal cancer

The development of cancer is a multi-step process involving the gradual loss of regulation over the growth and functional capabilities of normal cells. Much research has been focused on the numerous cell intrinsic factors that govern this process; however, recent attention has turned to understanding the cell extrinsic factors in the tumor microenvironment that appear equally critical to the progression and treatment of cancer. One critical component of the tumor microenvironment is the immune system and it has become increasingly evident that the immune system plays an integral role in preventing and promoting the development of cancer. Understanding the immune cell types and pathways involved in this process has enabled the development of novel biomarkers for prognosis and accelerated the development of immune-based therapeutics, both of which have the potential to forever change the treatment paradigms for colorectal cancer (CRC). In this review, we discuss the impact of the immune system on the initiation, progression and treatment of cancer, specifically focusing on CRC.

Overexpression of interleukin-18 protein reduces viability and induces apoptosis of tongue squamous cell carcinoma cells by activation of glycogen synthase kinase-3β signaling

The aim of this study was to investigate the effects of interleukin-18 (IL-18) expression on regulating the viability and apoptosis of tongue squamous cell carcinoma (TSCC) cells in vitro and examine the underlying molecular events. Human IL-18 cDNA was cloned into the vector pcDNA3.1 (+) and transfected into CRL-1623™ cells. Quantitative reverse transcription-PCR (RT-qPCR), western blot analysis, immunofluorescence, cell viability MTT assay, flow cytometric Annexin V/propidium iodide (PI), Giemsa staining, and caspase-3 activity assay were performed. The data showed that overexpression of IL-18 protein reduced TSCC cell viability by inducing apoptosis. Compared with cells transfected with the control vector, IL-18 expression activated caspase-3, -7, and -9 by inducing their cleavage and increased the expression of interferon (IFN)-γ and cytochrome c mRNA, but reduced cyclin D1 and A1 expression in TSCC cells. IL-18 expression upregulated the expression and phosphorylation of glycogen synthase kinase (GSK)-3β protein in CRL1623 cells, whereas the selective GSK-3β inhibitor kenpaullone antagonized the effects of IL-18 protein on TSCC cells in vitro. The results indicated that IL-18 played an important role in the inhibition of TSCC cell growth and may be further investigated as a novel therapeutic target against TSCC.