Interleukin-12 inhibits the survival of human colon cancer stem cells in vitro and their tumor initiating capacity in mice

Mycochemicals against Cancer Stem Cells

Since ancient times, mushrooms have been considered valuable allies of human well-being both from a dietary and medicinal point of view. Their essential role in several traditional medicines is explained today by the discovery of the plethora of biomolecules that have shown proven efficacy for treating various diseases, including cancer. Numerous studies have already been conducted to explore the antitumoural properties of mushroom extracts against cancer. Still, very few have reported the anticancer properties of mushroom polysaccharides and mycochemicals against the specific population of cancer stem cells (CSCs). In this context, β-glucans are relevant in modulating immunological surveillance against this subpopulation of cancer cells within tumours. Small molecules, less studied despite their spread and assortment, could exhibit the same importance. In this review, we discuss several pieces of evidence of the association between β-glucans and small mycochemicals in modulating biological mechanisms which are proven to be involved with CSCs development. Experimental evidence and an in silico approach are evaluated with the hope of contributing to future strategies aimed at the direct study of the action of these mycochemicals on this subpopulation of cancer cells.

Critical signaling pathways governing colitis-associated colorectal cancer: Signaling, therapeutic implications, and challenges

Long-term colitis in people with inflammatory bowel disease (IBD) may lead to colon cancer called colitis-associated colorectal cancer (CAC). Since the advent of preclinical prototypes of CAC, various immunological messaging cascades have been identified as implicated in developing this disease. The toll-like receptor (TLR)s, Janus kinase (JAK)-signal transducer and activator of transcription (STAT), Nuclear factor-kappa B (NF-κB), mammalian target of rapamycin complex (mTOR), autophagy, and oxidative stress are only a few of the molecular mechanisms that have been recognized as major components to CAC progression. These pathways may also represent attractive medicinal candidates for the prevention and management of CAC. CAC signaling mechanisms at the molecular level and how their dysregulation may cause illness are summarized in this comprehensive overview.

Tumor-Mediated Neutrophil Polarization and Therapeutic Implications

Neutrophils are immune cells with reported phenotypic and functional plasticity. Tumor-associated neutrophils display many roles during cancer progression. Several tumor microenvironment (TME)-derived factors orchestrate neutrophil release from the bone marrow, recruitment and functional polarization, while simultaneously neutrophils are active stimulators of the TME by secreting factors that affect immune interactions and subsequently tumor progression. Successful immunotherapies for many cancer types and stages depend on the targeting of tumor-infiltrating lymphocytes. Neutrophils impact the success of immunotherapies, such as immune checkpoint blockade therapies, by displaying lymphocyte suppressive properties. The identification and characterization of distinct neutrophil subpopulations or polarization states with pro- and antitumor phenotypes and the identification of the major TME-derived factors of neutrophil polarization would allow us to harness the full potential of neutrophils as complementary targets in anticancer precision therapies.

Preoperative Absolute Lymphocyte Count to Carcinoembryonic Antigen Ratio Is a Superior Predictor of Survival in Stage I to III Colorectal Cancer

Background:

Preoperative absolute lymphocyte count (ALC) and carcinoembryonic antigen (CEA) are useful prognostic indicators in colorectal cancer (CRC); however, the role of the ALC-to-CEA ratio (LCR) has been less addressed.

Methods:

A total of 189 stage I to III CRC patients who underwent radical resection were enrolled retrospectively. The significance of the LCR in predicting disease-free survival (DFS) and overall survival (OS) was calculated and compared with other markers based on ALC. The DFS and OS differences among the low- and high-LCR subgroups and risk factors for the outcome were estimated by Kaplan–Meier analysis and the Cox proportional hazards model, respectively.

Results:

Taking 0.28 as the cutoff point, the LCR has a sensitivity and a specificity of 75.60% and 77.00%, respectively, in predicting OS. The prognostic efficacy of LCR was significantly superior to that of other markers based on ALC for predicting DFS and OS. A total of 34.92% (66/189) of patients displayed a low LCR (<0.28), and these patients were more likely to present poor cell differentiation (P = .03), tumor deposits (P < .01) and advanced T (P < .01) and liver metastasis (P = .02). Patients with a low LCR had significantly worse DFS (Log Rank = 34.98, P < .01) and OS (Log Rank = 43.17, P < .01) than those with a high LCR. The LCR was an independent prognostic factor for both DFS (hazard ratio (HR) = 0.35, 95% confidence interval (CI): 0.20-0.62, P < .01) and OS (HR = 0.18, 95% CI: 0.08-0.37, P < .01).

Conclusions:

The LCR is a superior predictor of survival in stage I to III CRC, and patients with a low LCR have an inferior outcome; however, additional studies are required to validate its prognostic role.

Possible Roles of Interleukin-4 and -13 and Their Receptors in Gastric and Colon Cancer

Interleukin (IL)-4 and -13 are structurally and functionally related cytokines sharing common receptor subunits. They regulate immune responses and, moreover, are involved in the pathogenesis of a variety of human neoplasms. Three different receptors have been described for IL-4, but only IL-4 receptor type II (IL-4Rα/IL-13Rα1) is expressed in solid tumors. While IL-13 can also bind to three different receptors, IL-13 receptor type I (IL-4Rα/IL-13Rα1/IL-13Rα2) and type II (IL-4Rα/IL-13Rα1) are expressed in solid tumors. After receptor binding, IL-4 and IL-13 can mediate tumor cell proliferation, survival, and metastasis in gastric or colon cancer. This review summarizes the results about the role of IL-4/IL-13 and their receptors in gastric and colon cancer.

Cytokines in oncolytic virotherapy

Tumors represent a hostile environment for the effector cells of cancer immunosurveillance. Immunosuppressive receptors and soluble or membrane-bound ligands are abundantly exposed and released by malignant entities and their stromal accomplices. As a consequence, executioners of antitumor immunity inefficiently navigate across cancer tissues and fail to eliminate malignant targets. By inducing immunogenic cancer cell death, oncolytic viruses profoundly reshape the tumor microenvironment. They trigger the local spread of danger signals and tumor-associated (as well as viral) antigens, thus attracting antigen-presenting cells, promoting the activation and expansion of lymphocytic populations, facilitating their infiltration in the tumor bed, and reinvigorating cytotoxic immune activity. The present review recapitulates key chemokines, growth factors and other cytokines that orchestrate this ballet of antitumoral leukocytes upon oncolytic virotherapy.

Bioinformatics analysis and verification of molecular targets in ovarian cancer stem-like cells

BACKGROUND

Epithelial ovarian cancer (EOC) is a lethal and aggressive gynecological malignancy. Despite recent advances, existing therapies are challenged by a high relapse rate, eventually resulting in disease recurrence and chemoresistance. Emerging evidence indicates that a subpopulation of cells known as cancer stem-like cells (CSLCs) exists with non-tumorigenic cancer cells (non-CSCs) within a bulk tumor and is thought to be responsible for tumor recurrence and drug-resistance. Therefore, identifying the molecular drivers for cancer stem cells (CSCs) is critical for the development of novel therapeutic strategies for the treatment of EOC.

METHODS

Two gene datasets were downloaded from the Gene Expression Omnibus (GEO) database based on our search criteria. Differentially expressed genes (DEGs) in both datasets were obtained by the GEO2R web tool. Based on log2 (fold change) >2, the top thirteen up-regulated genes and log2 (fold change) < -1.5 top thirteen down-regulated genes were selected, and the association between their expressions and overall survival was analyzed by OncoLnc web tool. Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathways analysis, and protein-protein interaction (PPI) networks were performed for all the common DEGs found in both datasets. SK-OV-3 cells were cultured in an adherent culture medium and spheroids were generated in suspension culture with CSCs specific medium. RNA from both cell population was extracted to validate the selected DEGs expression by q-PCR. Growth inhibition assay was performed in SK-OV-3 cells after carboplatin treatment.

RESULTS

A total of 200 DEGs, 117 up-regulated and 83 down-regulated genes were commonly identified in both datasets. Analysis of pathways and enrichment tests indicated that the extracellular matrix part, cell proliferation, tissue development, and molecular function regulation were enriched in CSCs. Biological pathways such as interferon-alpha/beta signaling, molecules associated with elastic fibers, and synthesis of bile acids and bile salts were significantly enriched in CSCs. Among the top 13 up-regulated and down-regulated genes, MMP1 and PPFIBP1 expression were associated with overall survival. Higher expression of ADM, CXCR4, LGR5, and PTGS2 in carboplatin treated SK-OV-3 cells indicate a potential role in drug resistance.

CONCLUSIONS

The molecular signature and signaling pathways enriched in ovarian CSCs were identified by bioinformatics analysis. This analysis could provide further research ideas to find the new mechanism and novel potential therapeutic targets for ovarian CSCs.

Oncolytic Measles Virus Encoding Interleukin-12 Mediated Antitumor Activity and Immunologic Control of Colon Cancer In Vivo and Ex Vivo

Background: In this study, we used an oncolytic measles virus encoding interleukin 12 (IL-12) to treat colon cancer in vivo and ex vivo to investigate its effect on the viability and apoptosis of colon cancer cells. Method: A rat model was established to evaluate the immunostimulatory capabilities and therapeutic efficacy of vectors encoding an IL-12 fusion protein (MeVac FmIL-12 vectors). TUNEL staining, western blot, and enzyme-linked immunosorbent assay were performed to examine the impacts of MeVac FmIL-12 on the expression of inflammatory cytokines. Cell transfection was carried out to validate the anti-tumor role of MeVac FmIL-12 in vitro. Flow cytometry and MTT assay were performed to assess the effects of MeVac FmIL-12 on cell apoptosis and viability. Result: High concentrations (10-1000 ng/mL) of murine IL-12 fusion protein (FmIL-12) decreased the production of interferon γ (IFN-γ) in a concentration-dependent manner and reflected FmIL-12-induced overstimulation. Rats treated with MeVac vectors encoding FmIL-12 showed a significantly increased level of FmIL-12 overtime and a concentration-dependent (0.01-10 ng/mL) increase in IFN-γ production. MeVac FmIL-12 also increased the expression of inflammatory cytokines (IFN-γ, tumor necrosis factor α, and IL-6) both in vivo and in vitro. MeVac FmIL-12 promoted cell apoptosis and reduced cell viability, which helped to trigger a systemic anti-tumor immune response, both in vivo and in vitro. Conclusion: In this study, we suggested that MeVac FmIL-12 enhanced the therapeutic efficacy of tumor treatment by improving anti-tumor immunity.

A Functional Polymorphism in the Promoter Region of Interleukin-12B Increases the Risk of Colorectal Cancer

Objective

To investigate whether the polymorphisms of interleukin-12B (IL-12B) were associated with the risk of developing colorectal cancer (CRC). Patients and Methods. Genotypes of rs17860508 and rs3212227 were determined by polymerase chain reaction with a direct sequencing method in 329 CRC patients and 342 matched healthy control subjects. The expression of IL-12B) were associated with the risk of developing colorectal cancer (CRC).

Results

Compared with TTAGAG/TTAGAG genotype of rs17860508, the GC/GC and TTAGAG/GC genotypes may significantly increase the risk of CRC (OR = 1.81, 95% CI = 1.18-2.78; OR = 1.46, 95% CI = 1.01-2.12, respectively). Furthermore, the mRNA levels of IL-12B) were associated with the risk of developing colorectal cancer (CRC). P=0.009) and TTAGAG/TTAGAG (P=0.009) and TTAGAG/TTAGAG (.

Conclusion

These data suggested that the rs17860508 GC/GC genotype might upregulate IL-12B expression at the transcriptional level and thus increase the risk of CRC.IL-12B) were associated with the risk of developing colorectal cancer (CRC).

A novel BMI-1 inhibitor QW24 for the treatment of stem-like colorectal cancer

Background

Cancer-initiating cell (CIC), a functionally homogeneous stem-like cell population, is resonsible for driving the tumor maintenance and metastasis, and is a source of chemotherapy and radiation-therapy resistance within tumors. Targeting CICs self-renewal has been proposed as a therapeutic goal and an effective approach to control tumor growth. BMI-1, a critical regulator of self-renewal in the maintenance of CICs, is identified as a potential target for colorectal cancer therapy.

Methods

Colorectal cancer stem-like cell lines HCT116 and HT29 were used for screening more than 500 synthetic compounds by sulforhodamine B (SRB) cell proliferation assay. The candidate compound was studied in vitro by SRB cell proliferation assay, western blotting, cell colony formation assay, quantitative real-time PCR, flow cytometry analysis, and transwell migration assay. Sphere formation assay and limiting dilution analysis (LDA) were performed for measuring the effect of compound on stemness properties. In vivo subcutaneous tumor growth xenograft model and liver metastasis model were performed to test the efficacy of the compound treatment. Student’s t test was applied for statistical analysis.

Results

We report the development and characterization of a small molecule inhibitor QW24 against BMI-1. QW24 potently down-regulates BMI-1 protein level through autophagy-lysosome degradation pathway without affecting the BMI-1 mRNA level. Moreover, QW24 significantly inhibits the self-renewal of colorectal CICs in stem-like colorectal cancer cell lines, resulting in the abrogation of their proliferation and metastasis. Notably, QW24 significantly suppresses the colorectal tumor growth without obvious toxicity in the subcutaneous xenograft model, as well as decreases the tumor metastasis and increases mice survival in the liver metastasis model. Moreover, QW24 exerts a better efficiency than the previously reported BMI-1 inhibitor PTC-209.

Conclusions

Our preclinical data show that QW24 exerts potent anti-tumor activity by down-regulating BMI-1 and abrogating colorectal CICs self-renewal without obvious toxicity in vivo, suggesting that QW24 could potentially be used as an effective therapeutic agent for clinical colorectal cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1392-8) contains supplementary material, which is available to authorized users.

IL-8 regulates the stemness properties of cancer stem cells in the small-cell lung cancer cell line H446

PURPOSE

Cancer stem cells (CSCs) are a small population of cancer cells located within a tumor that are highly tumorigenic, capable of tumor initiation, and resistant to cancer therapies. We identified the potential genes involved in regulating stemness properties and investigated the mechanisms in small-cell lung cancer (SCLC).

MATERIALS AND METHODS

Whole transcriptome sequencing technology was used to screen the potential genes involved in regulating stemness properties from SCLC-SCs (uPAR+) and differentiated cells (uPAR-) in the H446 cell line. The selected genes were validated by quantitative reverse transcription PCR and ELISAs. The effect of IL-8 on stemness of sphere-forming cells was determined through tumor sphere formation, wound healing migration, and in vivo tumorigenesis assays.

RESULTS

In our study, uPAR+ and uPAR- cells showed different gene expression profiles. IL-8 was upregulated in SCLC sphere-forming cells. Blocking IL-8 expression with siRNA led to loss of stemness, including the self-renewal capability, migration, expression of stemness-related genes, and in vivo tumorigenicity, in sphere-forming cells. Consistently, exogenously added IL-8 enhanced stemness properties in parental cells.

CONCLUSION

IL-8 was upregulated in SCLC sphere-forming cells, and critical for the acquisition and/or maintenance of the stemness features in the SCLC cell line H446. Our results suggest that blocking IL-8 signaling may provide a novel therapeutic approach for targeting SCLC-SCs and improve treatment and outcomes in SCLC.

Turn Back the TIMe: Targeting Tumor Infiltrating Myeloid Cells to Revert Cancer Progression

Tumor cells frequently produce soluble factors that favor myelopoiesis and recruitment of myeloid cells to the tumor microenvironment (TME). Consequently, the TME of many cancer types is characterized by high infiltration of monocytes, macrophages, dendritic cells and granulocytes. Experimental and clinical studies show that most myeloid cells are kept in an immature state in the TME. These studies further show that tumor-derived factors mold these myeloid cells into cells that support cancer initiation and progression, amongst others by enabling immune evasion, tumor cell survival, proliferation, migration and metastasis. The key role of myeloid cells in cancer is further evidenced by the fact that they negatively impact on virtually all types of cancer therapy. Therefore, tumor-associated myeloid cells have been designated as the culprits in cancer. We review myeloid cells in the TME with a focus on the mechanisms they exploit to support cancer cells. In addition, we provide an overview of approaches that are under investigation to deplete myeloid cells or redirect their function, as these hold promise to overcome resistance to current cancer therapies.

Uncovering the underlying mechanism of cancer tumorigenesis and development under an immune microenvironment from global quantification of the landscape

The study of the cancer-immune system is important for understanding tumorigenesis and the development of cancer and immunotherapy. In this work, we build a comprehensive cancer-immune model including both cells and cytokines to uncover the underlying mechanism of cancer immunity based on landscape topography. We quantify three steady-state attractors, normal state, low cancer state and high cancer state, for the innate immunity and adaptive immunity of cancer. We also illustrate the cardinal inhibiting cancer immunity interactions and promoting cancer immunity interactions through global sensitivity analysis. We simulate tumorigenesis and the development of cancer and classify these into six stages. The characteristics of the six stages can be classified further into three groups. These correspond to the escape, elimination and equilibrium phases in immunoediting, respectively. Under specific cell-cell interactions strength oscillations emerge. We found that tumorigenesis and cancer recovery processes may need to go through cancer-immune oscillation, which consumes more energy. Based on the cancer-immune landscape, we predict three types of cells and two types of cytokines for cancer immunotherapy as well as combination immunotherapy. This landscape framework provides a quantitative way to understand the underlying mechanisms of the interplay between cancer and the immune system for cancer tumorigenesis and development.

Integrating Immunologic Signaling Networks: The JAK/STAT Pathway in Colitis and Colitis-Associated Cancer

Cytokines are believed to be crucial mediators of chronic intestinal inflammation in inflammatory bowel diseases (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC). Many of these cytokines trigger cellular effects and functions through signaling via janus kinase (JAK) and signal transducer and activator of transcription (STAT) molecules. In this way, JAK/STAT signaling controls important events like cell differentiation, secretion of cytokines or proliferation and apoptosis in IBD in both adaptive and innate immune cells. Moreover, JAK/STAT signaling, especially via the IL-6/STAT3 axis, is believed to be involved in the transition of inflammatory lesions to tumors leading to colitis-associated cancer (CAC). In this review, we will introduce the main cellular players and cytokines that contribute to pathogenesis of IBD by JAK/STAT signaling, and will highlight the integrative function that JAK/STATs exert in this context as well as their divergent role in different cells and processes. Moreover, we will explain current concepts of the implication of JAK/STAT signaling in CAC and finally discuss present and future therapies for IBD that interfere with JAK/STAT signaling.

The transduction pattern of IL-12-encoding lentiviral vectors shapes the immunological outcome

In situ modification of antigen-presenting cells garnered interest in cancer immunotherapy. Therefore, we developed APC-targeted lentiviral vectors (LVs). Unexpectedly, these LVs were inferior vaccines to broad tropism LVs. Since IL-12 is a potent mediator of antitumor immunity, we evaluated whether this proinflammatory cytokine could enhance antitumor immunity of an APC-targeted LV-based vaccine. Therefore, we compared subcutaneous administration of broad tropism LVs (VSV-G-LV) with APC-targeted LVs (DC2.1-LV)-encoding enhanced GFP and ovalbumin, or IL-12 and ovalbumin in mice. We show that codelivery of IL-12 by VSV-G-LVs or DC2.1-LVs augments CD4(+) or CD8(+) T-cell proliferation, respectively. Furthermore, we demonstrate that codelivery of IL-12 enhances the CD4(+) TH 1 profile irrespective of its delivery mode, while an increase in cytotoxic and therapeutic CD8(+) T cells was only induced upon VSV-G-LV injection. While codelivery of IL-12 by DC2.1-LVs did not enhance CD8(+) T-cell performance, it increased expression of inhibitory checkpoint markers Lag3, Tim3, and PD-1. Finally, the discrepancy between CD4(+) T-cell stimulation with and without functional CD8(+) T-cell stimulation by VSV-G- and DC2.1-LVs is partly explained by the observation that IL-12 relieves CD8(+) T cells from CD4(+) T-cell help, implying that a T(H)1 profile is of minor importance for antitumor immunotherapy if IL-12 is exogenously delivered.

Interaction analysis of IL-12A and IL-12B polymorphisms with the risk of colorectal cancer

IL-12 is an antitumor cytokine with functions of inhibiting tumor growth, invasion, and metastasis, indicating that IL-12 is a promising candidate for cancer treatment. The aim of this study was to investigate the association of IL-12A rs568408, IL-12A rs2243115, and IL-12B rs3212227 with the susceptibility to colorectal cancer (CRC). Two hundred and fifty-seven histopathologically confirmed CRC patients and 236 age- and gender-matched controls were enrolled. The three polymorphisms were genotyped using a polymerase chain reaction-restriction fragment length polymorphism assay. We found that the IL-12A rs568408 AG/AA genotypes were associated with an increased risk of CRC with an adjusted odds ratio (OR) of 1.66 (95 % confidence interval (CI), 1.11-2.48). Stratified analyses showed that patients carrying the IL-12B rs3212227AC/CC genotypes had a 1.97-fold increased risk of tumor metastasis (OR = 1.97; 95 % CI, 1.04-3.70). Gene-gene interaction analysis showed that subjects carrying the IL-12A rs568408AG/AA and IL-12B rs3212227AA genotypes had a 2.40-fold increased risk of CRC (OR = 2.40; 95 % CI, 1.14-5.07) and individuals carrying the IL-12A rs568408AG/AA and IL-12B rs3212227AC/CC genotypes had a 1.93-fold increased risk of CRC (OR = 1.93; 95 % CI, 1.10-3.41). These findings indicate that IL-12A rs568408 and IL-12B rs3212227 may be related to the development of CRC.

Targeting the tumor microenvironment to enhance antitumor immune responses

The identification of tumor-specific antigens and the immune responses directed against them has instigated the development of therapies to enhance antitumor immune responses. Most of these cancer immunotherapies are administered systemically rather than directly to tumors. Nonetheless, numerous studies have demonstrated that intratumoral therapy is an attractive approach, both for immunization and immunomodulation purposes. Injection, recruitment and/or activation of antigen-presenting cells in the tumor nest have been extensively studied as strategies to cross-prime immune responses. Moreover, delivery of stimulatory cytokines, blockade of inhibitory cytokines and immune checkpoint blockade have been explored to restore immunological fitness at the tumor site. These tumor-targeted therapies have the potential to induce systemic immunity without the toxicity that is often associated with systemic treatments. We review the most promising intratumoral immunotherapies, how these affect systemic antitumor immunity such that disseminated tumor cells are eliminated, and which approaches have been proven successful in animal models and patients.

Experimental study on enhancement of the metastatic potential of portal vein tumor thrombus-originated hepatocellular carcinoma cells using portal vein serum

OBJECTIVE

Portal vein metastasis of hepatocellular carcinoma (HCC) results in a poor prognosis and seriously affects the survival rate of patients. The mechanism underlying the formation of portal vein tumor thrombus (PVTT) is complex and is not yet fully understood. This study was conducted to investigate the impact of portal vein blood on the proliferation, metastasis, invasion and apoptosis of PVTT cells and to explore its possible mechanisms, which was expected to lay a foundation for ascertaining the mechanism underlying the portal vein metastasis of HCC.

METHODS

Peripheral blood and portal vein blood were collected from patients with HCC, and the sera from these two sources were used to culture the PVTT-originated HCC cell line CSQT-2. The cells were collected after 24 h, and flow cytometry was performed to detect cell proliferation, cell cycle stages and apoptosis. Transwell migration and invasion assays were applied to detect the metastasis and invasion of the cells in each group. The changes in the expression of MMP-2 and MMP-9 in cells were detected via Western blotting. The contents of IL-12, IFN-γ, IL-1β, IL-2 and TNF-α in the two groups of sera were quantified using corresponding kits.

RESULTS

Compared with the group of cells cultured with peripheral serum, the cells cultured with portal vein serum showed significantly lower apoptosis (P<0.01), significantly enhanced cell metastasis and invasion (P<0.01), whereas cell proliferation and the stages of the cell cycle did not differ significantly (P>0.05). A significantly increased expression level of MMP-2 has been observed in tumor cells treated portal vein serum. In addition, compared with peripheral serum, the content of IL-12 was significantly decreased in portal vein serum (P<0.05), while the contents of IFN-γ, IL-1β, IL-2, and TNF-α did not differ significantly (P>0.05).

CONCLUSIONS

Portal vein serum from HCC patients could inhibit the apoptosis of PVTT-originated HCC cells and promote cell metastasis and invasion. This effect may be related to the lower level of IL-12 in portal vein serum.

Localized interleukin-12 delivery for immunotherapy of solid tumours

Interleukin (IL)-12 is the key cytokine in the initiation of a Th1 response and has shown promise as an anti-cancer agent; however, clinical trials involving IL-12 have been unsuccessful due to toxic side-effects. To address this issue, lentiviral vectors were used to transduce tumour cell lines that were injected as an autologous tumour cell vaccine. The focus of the current study was to test the efficacy of this approach in a solid tumour model. SCCVII cells that were transduced to produce IL-12 at different concentrations were then isolated. Subcutaneous injection of parental SCCVII cells results in tumour development, while a mixture of IL-12-producing and non-producing cells results in tumour clearance. Interestingly, when comparing mice injected a mixture of SCCVII and either high IL-12-producing tumour cells or low IL-12-producing tumour cells, we observed that mixtures containing small amounts of high producing cells lead to tumour clearance, whereas mixtures containing large amounts of low producing cells fail to elicit protection, despite the production of equal amounts of total IL-12 in both mixtures. Furthermore, immunizing mice with IL-12-producing cells leads to the establishment of both local and systemic immunity against challenge with SCCVII. Using depletion antibodies, it was shown that both CD4(+) and CD8(+) cells are crucial for therapy. Lastly, we have established cell clones of other solid tumour cell lines (RM-1, LLC1 and moto1.1) that produce IL-12. Our results show that the delivery of IL-12 by cancer cells is an effective route for immune activation.

Preparation and characterization of gelatin nanoparticles containing pDNA encoding IL-12 and their expression in CT-26 carcinoma cells

Aim: Gelatin as a biodegradable, nontoxic and biocompatible natural protein is a good candidate for gene delivery. In this study, pDNA-loaded gelatin nanoparticles were prepared and characterized for the expression of the cytokine IL-12 and anti-tumor effects. Materials & methods: Gelatin–pUMVC3–hIL-12 nanoparticles were prepared by the ethanol precipitation technique and evaluated for physicochemical characteristics, cytotoxiciy and transfection efficiency. Results: The prepared particles were spherical in shape with sizes varying from 344.27 to 826.23 nm, ζ-potentials between -944 and -165 mV, and greater than 97% encapsulation efficiency. The particles were nontoxic to CT-26 carcinoma cells. The nanoparticles prepared using 0.5% gelatin solution (G14) with a mean particle size of 816.87 nm (polydispersity index = 0.56 ± 0.01) demonstrated maximum transfection efficiency with 2.5-times higher expression compared with the naked plasmid. Conclusion: Gelatin–DNA nanoparticles using 0.5% gelatin solution had minimal cytotoxicity and can be used as a suitable candidate for further gene delivery studies and applications.