Enhanced antitumor immunity is elicited by adenovirus-mediated gene transfer of CCL21 and IL-15 in murine colon carcinomas

Chemokine systems in oncology: From microenvironment modulation to nanocarrier innovations

Over the past few decades, significant strides have been made in understanding the pivotal roles that chemokine networks play in tumor biology. These networks, comprising chemokines and their receptors, wield substantial influence over cancer immune regulation and therapeutic outcomes. As a result, targeting these chemokine systems has emerged as a promising avenue for cancer immunotherapy. However, therapies targeting chemokines face significant challenges in solid tumor treatment, due to the complex and fragile of the chemokine networks. A nuanced comprehension of the complicacy and functions of chemokine networks, and their impact on the tumor microenvironment, is essential for optimizing their therapeutic utility in oncology. This review elucidates the ways in which chemokine networks interact with cancer immunity and tumorigenesis. We particularly elaborate on recent innovations in manipulating these networks for cancer treatment. The review also highlights future challenges and explores potential biomaterial strategies for clinical applications.

Integrated multi-omics approach to distinct molecular characterization and classification of early-onset colorectal cancer

Incidence of early-onset colorectal cancer (EOCRC), defined by a diagnosed age under 50 years, is increasing, but its heterogeneous etiologies that differ from general CRC remain undetermined. We initially characterize the genome, epigenome, transcriptome, and proteome of tumors from 79 patients in a Chinese CRC cohort. Data for an additional 126 EOCRC subjects are obtained from the International Cancer Genome Consortium Chinese cohort and The Cancer Genome Atlas European cohort. We observe that early-onset tumors have a high tumor mutation burden; increased DNA repair features by mutational signature 3 and multi-layer pathway enrichments; strong perturbations at effects of DNA methylation and somatic copy-number alteration on gene expression; and upregulated immune infiltration as hot tumors underlying immunophenotypes. Notably, LMTK3 exhibits ancestral mutation disparity, potentially being a functional modulator and biomarker that drives molecular alterations in EOCRC development and immunotherapies. This integrative omics study provides valuable knowledge for precision oncology of CRC.

Strategy and application of manipulating DCs chemotaxis in disease treatment and vaccine design

As the most versatile antigen-presenting cells (APCs), dendritic cells (DCs) function as the cardinal commanders in orchestrating innate and adaptive immunity for either eliciting protective immune responses against canceration and microbial invasion or maintaining immune homeostasis/tolerance. In fact, in physiological or pathological conditions, the diversified migratory patterns and exquisite chemotaxis of DCs, prominently manipulate their biological activities in both secondary lymphoid organs (SLOs) as well as homeostatic/inflammatory peripheral tissues in vivo. Thus, the inherent mechanisms or regulation strategies to modulate the directional migration of DCs even could be regarded as the crucial cartographers of the immune system. Herein, we systemically reviewed the existing mechanistic understandings and regulation measures of trafficking both endogenous DC subtypes and reinfused DCs vaccines towards either SLOs or inflammatory foci (including neoplastic lesions, infections, acute/chronic tissue inflammations, autoimmune diseases and graft sites). Furthermore, we briefly introduced the DCs-participated prophylactic and therapeutic clinical application against disparate diseases, and also provided insights into the future clinical immunotherapies development as well as the vaccines design associated with modulating DCs mobilization modes.

In silico analysis and in planta production of recombinant ccl21/IL1β protein and characterization of its in vitro anti-tumor and immunogenic activity

CCL21 has an essential role in anti-tumor immune activity. Epitopes of IL1β have adjuvant activity without causing inflammatory responses. CCR7 and its ligands play a vital role in the immune balance; specifically, in transport of T lymphocytes and antigen-presenting cells such as dendritic cells to the lymph nodes. This study aimed to produce epitopes of CCL21 and IL1β as a recombinant protein and characterize its in vitro anti-tumor and immunogenic activity. A codon-optimized ccl21/IL1β gene was designed and synthesized from human genes. Stability and binding affinity of CCL21/IL1β protein and CCR7 receptor were examined through in silico analyses. The construct was introduced into N. tabacum to produce this recombinant protein and the structure and function of CCL21/IL1β were examined. Purified protein from transgenic leaves generated a strong signal in SDS PAGE and western blotting assays. FTIR measurement and MALDI-TOF/TOF mass spectrography showed that ccl21/IL-1β was correctly expressed in tobacco plants. Potential activity of purified CCL21/IL1β in stimulating the proliferation and migration of MCF7 cancer cell line was investigated using the wound healing method. The results demonstrated a decrease in survival rate and metastasization of cancer cells in the presence of CCL21/IL1β, and IC50 of CCL21 on MCF7 cells was less than that of non-recombinant protein. Agarose assay on PBMCsCCR7+ showed that CCL21/IL1β has biological activity and there is a distinguishable difference between chemokinetic (CCL21) and chemotactic (FBS) movements. Overall, the results suggest that CCL21/IL1β could be considered an effective adjuvant in future in vivo and clinical tests.

CCR7 as a therapeutic target in Cancer

The CCR7 chemokine axis is comprised of chemokine ligand 21 (CCL21) and chemokine ligand 19 (CCL19) acting on chemokine receptor 7 (CCR7). This axis plays two important but apparently opposing roles in cancer. On the one hand, this axis is significantly engaged in the trafficking of a number of effecter cells involved in mounting an immune response to a growing tumour. This suggests therapeutic strategies which involve potentiation of this axis can be used to combat the spread of cancer. On the other hand, the CCR7 axis plays a significant role in controlling the migration of tumour cells towards the lymphatic system and metastasis and can thus contribute to the expansion of cancer. This implies that therapeutic strategies which involve decreasing signaling through the CCR7 axis would have a beneficial effect in preventing dissemination of cancer. This dichotomy has partly been the reason why this axis has not yet been exploited, as other chemokine axes have, as a therapeutic target in cancer. Recent report of a crystal structure for CCR7 provides opportunities to exploit this axis in developing new cancer therapies. However, it remains unclear which of these two strategies, potentiation or antagonism of the CCR7 axis, is more appropriate for cancer therapy. This review brings together the evidence supporting both roles of the CCR7 axis in cancer and examines the future potential of each of the two different therapeutic approaches involving the CCR7 axis in cancer.

Delivery systems for enhancing oncolytic adenoviruses efficacy

Oncolytic adenovirus (OAds) has long been considered a promising biotherapeutic agent against various types of cancer owing to selectively replicate in and lyse cancer cells, while remaining dormant in healthy cells. In the last years, multiple (pre)clinical studies using genetic engineering technologies enhanced OAds anti-tumor effects in a broad range of cancers. However, poor targeting delivery, tropism toward healthy tissues, low-level expression of Ad receptors on tumor cells, and pre-existing neutralizing antibodies are major hurdles for systemic administration of OAds. Different vehicles have been developed for addressing these obstacles, such as stem cells, nanoparticles (NPs) and shielding polymers, extracellular vesicles (EVs), hydrogels, and microparticles (MPs). These carriers can enhance the therapeutic efficacy of OVs through enhancing transfection, circulatory longevity, cellular interactions, specific targeting, and immune responses against cancer. In this paper, we reviewed adenovirus structure and biology, different types of OAds, and the efficacy of different carriers in systemic administration of OAds.

Dietary plant extracts modulate gene expression profiles in alveolar macrophages of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

BACKGROUND

Our previous study showed that 3 plant extracts enhanced the immune responses and growth efficiency of weaned pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV), which is one of the most economically important disease in swine industry. However, each plant extract differently effected on growth efficiency and immune responses. Therefore, the objective of this study was conducted to characterize the effects and investigate the potential underlying mechanisms of 3 plant extracts on gene expression of alveolar macrophages in weaned pigs experimentally infected with PRRSV.

RESULTS

PRRSV infection altered (P < 0.05) the expression of 1,352 genes in pigs fed the control (CON; 755 up, 597 down). Compared with the infected CON, feeding capsicum (CAP), garlic botanical (GAR), or turmeric oleoresin (TUR) altered the expression of 46 genes (24 up, 22 down), 134 genes (59 up, 75 down), or 98 genes (55 up, 43 down) in alveolar macrophages of PRRSV-infected pigs, respectively. PRRSV infection up-regulated (P < 0.05) the expression of genes related to cell apoptosis, immune system process, and response to stimulus, but down-regulated (P < 0.05) the expression of genes involved in signaling transduction and innate immune response. Compared with the infected CON, feeding TUR or GAR reduced (P < 0.05) the expression of genes associated with antigen processing and presentation, feeding CAP up-regulated (P < 0.05) the expression of genes involved in antigen processing and presentation. Supplementation of CAP, GAR, or TUR also enhanced (P < 0.05) the expression of several genes related to amino acid metabolism, steroid hormone synthesis, or RNA degradation, respectively.

CONCLUSIONS

The results suggest that 3 plant extracts differently regulated the expression of genes in alveolar macrophages of PRRSV-infected pigs, especially altering genes involved in immunity.

Oncolytic adenovirus: A tool for cancer therapy in combination with other therapeutic approaches

Cancer therapy using oncolytic viruses is an emerging area, in which viruses are engineered to selectively propagate in tumor tissues without affecting healthy cells. Because of the advantages that adenoviruses (Ads) have over other viruses, they are more considered. To achieve tumor selectivity, two main modifications on Ads genome have been applied: small deletions and insertion of tissue- or tumor-specific promoters. Despite oncolytic adenoviruses ability in tumor cell lysis and immune responses stimulation, to further increase their antitumor effects, genomic modifications have been carried out including insertion of checkpoint inhibitors and antigenic or immunostimulatory molecules into the adenovirus genome and combination with dendritic cells and chemotherapeutic agents. This study reviews oncolytic adenoviruses structures, their antitumor efficacy in combination with other therapeutic strategies, and finally challenges around this treatment approach.

A folate receptor-targeted lipoplex delivering interleukin-15 gene for colon cancer immunotherapy

Interleukin-15 has been implicated as a promising cytokine for cancer immunotherapy, while folate receptor α (FRα) has been shown to be a potentially useful target for colon cancer therapy. Herein, we developed F-PLP/pIL15, a FRα-targeted lipoplex loading recombinant interleukin-15 plasmid (pIL15) and studied its antitumor effects in vivo using a CT26 colon cancer mouse model. Compared with control (normal saline) treatment, F-PLP/pIL15 significantly suppressed tumor growth in regard to tumor weight (P < 0.001) and reduced tumor nodule formation (P < 0.001). Moreover, when compared to other lipoplex-treated mice, F-PLP/pIL15-treated mice showed higher levels of IL15 secreted in the serum (P < 0.001) and ascites (P < 0.01). These results suggested that the targeted delivery of IL15 gene might be associated with its in vivo antitumor effects, which include inducing tumor cell apoptosis, inhibiting tumor proliferation and promoting the activation of immune cells such as T cells and natural killer cells. Furthermore, hematoxylin and eosin staining of vital organs following F-PLP/pIL15 treatment showed no detectable toxicity, thus indicating that intraperitoneal administration may be a viable route of delivery. Overall, these results suggest that F-PLP/pIL15 may serve as a potential targeting preparation for colon cancer therapy.

Transient expression of CCL21as recombinant protein in tomato

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Applied use of plants as bioreactors for production of recombinant proteins.

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The present study is the first to report gene expression of ccl21 construct in tomato via agro infiltration to use this plant as oral vaccine.

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To investigate the role of this protein in anti-metastatic function on cancer cells

The main goal of this study was to investigate the possibility of expressing recombinant protein of C-C chemokine ligand 21 (CCL21) in Solanum lycopersicum via agroinfiltration. CCL21 is a chemokine can be used for anti-metastatic of cancer cell lines. To examine the expression of CCL21 protein in S. lycopersicum, the construct of ccl21 was synthesized. This construct was cloned into pBI121 and the resulting CCL21 plasmid was agro-infiltrated into S. lycopersicum leaves. Within three days after infiltration, Expression of the foreign gene was confirmed by quantitative Real-time PCR. A recombinant CCL21 protein was immunogenically detected by western blot, dot blot and ELISA assay. And results showed that the foreign gene was expressed in the transformed leaves in high level. Also scratch assay was used to investigate the role of this protein in anti-metastatic function. The results demonstrated anti-metastatic of cancer cells in the presence of this protein.

Tumor location impacts immune response in mouse models of colon cancer

Existing preclinical models of human colorectal cancer (CRC) that rely on syngeneic subcutaneous grafts are problematic, because of increasing evidence that the immune microenvironment in subcutaneous tissue is significantly different from the gastrointestinal tract. Similarly, existing orthotopic models that use a laparotomy for establishing grafts are also problematic, because the surgical procedure results in extensive inflammation, thereby creating a nonphysiologic tumor microenvironment. To facilitate the bench-to-bedside translation of CRC immunotherapy strategies, we developed a novel orthotopic model in mice that uses endoscopy-guided microinjection of syngeneic cancer cells. When we compared immune system infiltration, we found that tumors in the subcutaneous model had fewer T cells, B cells, and natural killer (NK) cells, but more immunosuppressive myeloid cells; in contrast, tumors in our orthotopic model had a higher number of tumor-infiltrating T cells, B cells, and NK cells, with fewer immunosuppressive myeloid cells. The number of immune-stimulating cytokines, such as interleukin (IL)-2, IL-6, interferon (IFN)-gamma, and granzyme B, was also higher in tumors in our model, as compared with the subcutaneous model. Those differences resulted in heightened sensitivity to immune checkpoint blockade therapy in our endoscopy-guided orthotopic CRC model. Our study indicates that tumor location affects immune response in CRC mouse models; choosing the appropriate preclinical model is important when testing immunotherapy in CRC.

In Vivo Antitumor Activity of a Recombinant IL7/IL15 Hybrid Cytokine in Mice

Both IL7 and IL15 have become important candidate immunomodulators for cancer treatment. However, IL7 or IL15 used alone suffers from shortcomings, such as short serum half-life and limited antitumor effect. We have cloned and expressed a recombinant (r) IL7/IL15 fusion protein in which IL7 and IL15 are linked by a flexible linker. We then compared the antitumor effect of rIL7/IL15 with the individual factors rIL7 and/or rIL15. We show here that rIL7/IL15 has a higher antitumor activity than the combination of the individual factors in both murine B16F10 melanoma and CT-26 colon cancer models. This was associated with a significant increase in tumor infiltration of T cells, DCs, and NK cells and a decrease in regulatory T cells (Tregs). In addition, rIL7/IL15-treated DCs had higher expression of costimulatory molecules CD80 and CD86. The higher antitumor activity of rIL7/IL15 is likely due to its longer in vivo half-life and different effects on immune cells. Our results suggest that rIL7/IL15 may offer a new tool to enhance antitumor immunity and treat cancer. Mol Cancer Ther; 15(10); 2413-21. ©2016 AACR.

Immunotherapeutic effects of cytokine-induced killer cells combined with CCL21/IL15 armed oncolytic adenovirus in TERT-positive tumor cells

The effective antitumor immune responses are dependent on coordinate interaction of various effector cells. Thus, the combination of adoptive immunotherapy and target gene therapy is capable of efficiently generating a productive antitumor immune response. We investigated whether combination of cytokine-induced killer (CIK) cells adoptive immunotherapy and CCL21/IL15 armed oncolytic adenovirus could induce the enhanced antitumor activity. The CCL21/IL15 co-expression oncolytic adenoviruses were constructed by using the AdEasy system, which uses homologous recombination with shuttle plasmids and full length Ad backbones. This conditionally replicating adenoviruses CRAd-CCL21-IL15 could induce apoptosis in TERTp-positive tumor cells for viral propagation, but do not replicate efficiently in normal cells, because the E1A promoter was replaced by telomerase reverse transcriptase promoter (TERTp). Our results showed that the combination of CIK cells and CRAd-CCL21-IL15 could induce higher antitumor activity than either CIK cells or CRAd-CCL21-IL15 alone. This combined treatment could induce the tumor specific cytotoxicity of CTLs (cytotoxic T lymphocytes) in vitro. Moreover, the treatment of established tumors with the combined therapy of CIK cells and CRAd-CCL21-IL15 resulted in tumor regression. This study suggests that the combined treatment by adoptive immunotherapy and gene therapy is a promising strategy for the therapy of tumor.

CCL21/IL21-armed oncolytic adenovirus enhances antitumor activity against TERT-positive tumor cells

Multigene-armed oncolytic adenoviruses are capable of efficiently generating a productive antitumor immune response. The chemokine (C-C motif) ligand 21 (CCL21) binds to CCR7 on naïve T cells and dendritic cells (DCs) to promote their chemoattraction to the tumor and resultant antitumor activity. Interleukin 21 (IL21) promotes survival of naïve T cells while maintaining their CCR7 surface expression, which increases their capacity to transmigrate in response to CCL21 chemoattraction. IL21 is also involved in NK cell differentiation and B cell activation and proliferation. The generation of effective antitumor immune responses is a complex process dependent upon coordinated interactions of various subsets of effector cells. Using the AdEasy system, we aimed to construct an oncolytic adenovirus co-expressing CCL21 and IL21 that could selectively replicate in TERTp-positive tumor cells (Ad-CCL21-IL21 virus). The E1A promoter of these oncolytic adenoviruses was replaced by telomerase reverse transcriptase promoter (TERTp). Ad-CCL21-IL21 was constructed from three plasmids, pGTE-IL21, pShuttle-CMV-CCL21 and AdEasy-1 and was homologously recombined and propagated in the Escherichia coli strain BJ5183 and the packaging cell line HEK-293, respectively. Our results showed that our targeted and armed oncolytic adenoviruses Ad-CCL21-IL21 can induce apoptosis in TERTp-positive tumor cells to give rise to viral propagation, in a dose-dependent manner. Importantly, we confirm that these modified oncolytic adenoviruses do not replicate efficiently in normal cells even under high viral loads. Additionally, we investigate the role of Ad-CCL21-IL21 in inducing antitumor activity and tumor specific cytotoxicity of CTLs in vitro. This study suggests that Ad-CCL21-IL21 is a promising targeted tumor-specific oncolytic adenovirus.

IL15 and T-cell Stemness in T-cell-Based Cancer Immunotherapy

Preclinical models revealed that the immune system can mediate rejection of established tumors, but direct evidence in humans has been limited to largely immunogenic tumors, such as melanoma. The recent success of immune checkpoint inhibitors and adoptive T-cell transfer immunotherapy in clinical trials has instilled new hope for the use of T-cell immunotherapy in the treatment of cancer. IL15, a potent immunostimulatory cytokine, both potentiates host T-cells and natural killer (NK) cell immune responses and promotes the generation of long-lived memory T cells with superior functional capacity, with potential use in adoptive T-cell transfer protocols. IL15 has been recently tested in the clinic and showed dramatic effects at the level of responding NK and CD8(+) memory T cells. The recent advances in the knowledge of IL15-dependent regulation of T-cell responses, gene expression, and metabolic adaptation have important implications for the use of IL15 in T-cell-based immunotherapy of cancer.

Immunostimulatory Gene Therapy Using Oncolytic Viruses as Vehicles

Immunostimulatory gene therapy has been developed during the past twenty years. The aim of immunostimulatory gene therapy is to tilt the suppressive tumor microenvironment to promote anti-tumor immunity. Hence, like a Trojan horse, the gene vehicle can carry warriors and weapons into enemy territory to combat the tumor from within. The most promising immune stimulators are those activating and sustaining Th1 responses, but even if potent effects were seen in preclinical models, many clinical trials failed to show objective responses in cancer patients. However, with new tools to control ongoing immunosuppression in cancer patients, immunostimulatory gene therapy is now emerging as an interesting option. In parallel, oncolytic viruses have been shown to be safe in patients. To prolong immune stimulation and to increase efficacy, these two fields are now merging and oncolytic viruses are armed with immunostimulatory transgenes. These novel agents are racing towards approval as established cancer immunotherapeutics.

Human fused NKG2D-IL-15 protein controls xenografted human gastric cancer through the recruitment and activation of NK cells

Interleukin (IL)-15 plays an important role in natural killer (NK) and CD8+ T-cell proliferation and function and is more effective than IL-2 for tumor immunotherapy. The trans-presentation of IL-15 by neighboring cells is more effective for NK cell activation than its soluble IL-15. In this study, the fusion protein dsNKG2D-IL-15, which consisted of two identical extracellular domains of human NKG2D coupled to human IL-15 via a linker, was engineered in Escherichia coli. DsNKG2D-IL-15 could efficiently bind to major histocompatibility complex class I chain-related protein A (MICA) of human tumor cells with the two NKG2D domains and trans-present IL-15 to NK or CD8+ T cells. We transplanted human gastric cancer (SGC-7901) cells into nude mice and mouse melanoma cells with ectopic expression of MICA (B16BL6-MICA) into C57BL/6 mice. Then, we studied the anti-tumor effects mediated by dsNKG2D-IL-15 in the two xenografted tumor models. Human dsNKG2D-IL-15 exhibited higher efficiency than IL-15 in suppressing gastric cancer growth. Exogenous human dsNKG2D-IL-15 was centrally distributed in the mouse tumor tissues based on in vivo live imaging. The frequencies of human CD56+ cells infiltrated into the tumor tissues following the injection of peripheral blood mononuclear cells into nude mice bearing human gastric cancer were significantly increased by human dsNKG2D-IL-15 treatment. Human dsNKG2D-IL-15 also delayed the growth of transplanted melanoma (B16BL6-MICA) by activating and recruiting mouse NK and CD8+ T cells. The anti-melanoma effect of human dsNKG2D-IL-15 in C57BL/6 mice was mostly decreased by the in vivo depletion of mouse NK cells. These data highlight the potential use of human dsNKG2D-IL-15 for tumor therapy.Cellular & Molecular Immunology advance online publication, 14 September 2015; doi:10.1038/cmi.2015.81.

Enhanced growth suppression of TERT-positive tumor cells by oncolytic adenovirus armed with CCL20 and CD40L

Conditionally replicating adenoviruses (CRAds) selectively replicate in cancer cells and induce cell lysis, which represents a potential platform for cancer immunotherapy. The chemokine CCL20 exerts antitumor activity via chemoattraction of immature dendritic cells (DCs) and lymphocytes. However, the activation and maturation status of DCs is a limiting factor in the DCs -based immunity response. CD40L induces the phenotypic maturation of DCs, mediates DCs cytokine secretion, and increases the expression of FasL, which mediates apoptosis. We constructed a CCL20/CD40L co-expression CRAds (Ad-CCL20-CD40L) based on the AdEasy system. Ad-CCL20-CD40L was constructed from three plasmids, pGTE-CD40L, pShuttle-CMV-CCL20 and AdEasy-1, and was homologously recombined and propagated in the Escherichia coli strain BJ5183 and the packaging cell line HEK-293, respectively. Ad-CCL20-CD40L selectively replicates in TERT-positive tumor cells because the pGTE-CD40L plasmid contains the telomerase reverse transcriptase promoter (TERTp). Our results showed that Ad-CCL20-CD40L induced oncolytic effects and tumor-specific cytotoxicity of cytotoxic T lymphocytes (CTLs) in vitro. This study suggests that Ad-CCL20-CD40L can induce the antitumor immune response and that this platform can be modified to generate novel CRAds with other transgenes.

Interleukin-15: new kid on the block for antitumor combination therapy

Interleukin (IL)-15 is one of the most promising molecules to be used in antitumor immune therapy, as it is able to stimulate the main killer cells of both the innate and adaptive immune system. Although this cytokine can be used as a stand-alone immunotherapeutic agent, IL-15 will probably be most efficient in combination with other strategies to overcome high tumor burden, immune suppression of the tumor microenvironment and/or the short half-life of IL-15. In this review, we will discuss the combination strategies with IL-15 that have been tested to date in different animal tumor models, which include chemotherapy, other immunostimulatory cytokines, targeted therapy, adoptive cell transfer and gene therapy. In addition, we give an overview of IL-15 combination therapies that are currently tested in clinical studies to treat patients with hematological or advanced solid tumors.