Macrophage-derived chemokine gene transfer results in tumor regression in murine lung carcinoma model through efficient induction of antitumor immunity

Integration of single-cell sequencing and bulk expression data reveals chemokine signaling pathway in proliferating cells is associated with the survival outcome of osteosarcoma

BACKGROUND

Osteosarcoma, as the most common primary bone malignancy, is urgent to be well-studied on the biomarkers and therapeutic targets to improve the five-year survival rate. Transcriptomic analysis using single-cell RNA or bulk RNA sequencing has been developed to detect biomarkers in various cancer types.

METHODS AND RESULTS

We applied Scissor to combine single-cell RNA-seq data and bulk transcriptome data of osteosarcoma, providing cell-level information and sample phenotypes to identify the survival-associated cell subpopulations. By investigating the differences between the survival-associated cell subpopulations, we identified CCL21, CCL22, CCL24, CXCL11, CXCL12, CXCL13, GNAI2, and RAC2 in the proliferating cells that are significantly associated with osteosarcoma patient outcome. Then we assigned the risk score for each sample based on the cell proportion-normalized gene expression and validated it in the public dataset.

CONCLUSIONS

This study provides the clinical insight that chemokine signaling pathway genes (CCL21, CCL22, CCL24, CXCL11, CXCL12, CXCL13, GNAI2, and RAC2) in proliferating cells might be the potential biomarkers for treatment of osteosarcoma.

A systematic pan-cancer analysis reveals the clinical prognosis and immunotherapy value of C-X3-C motif ligand 1 (CX3CL1)

It is now widely known that C-X3-C motif ligand 1 (CX3CL1) plays an essential part in the process of regulating pro-inflammatory cells migration across a wide range of inflammatory disorders, including a number of malignancies. However, there has been no comprehensive study on the correlation between CX3CL1 and cancers on the basis of clinical features. In order to investigate the potential function of CX3CL1 in the clinical prognosis and immunotherapy, I evaluated the expression of CX3CL1 in numerous cancer types, methylation levels and genetic alterations. I found CX3CL1 was differentially expressed in numerous cancer types, which indicated CX3CL1 may plays a potential role in tumor progression. Furthermore, CX3CL1 was variably expressed in methylation levels and gene alterations in most cancers according to The Cancer Genome Atlas (TCGA). CX3CL1 was robustly associated with clinical characteristics and pathological stages, suggesting that it was related to the degree of tumor malignancy and the physical function of patients. As determined by the Kaplan-Meier method of estimating survival, high CX3CL1 expression was associated with either favorable or unfavorable outcomes depending on the different types of cancer. It suggests the correlation between CX3CL1 and tumor prognosis. Significant positive correlations of CX3CL1 expression with CD4+ T cells, M1 macrophage cells and activated mast cells have been established in the majority of TCGA malignancies. Which indicates CX3CL1 plays an important role in tumor immune microenvironment. Gene Ontology (GO) terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis suggested that the chemokine signaling pathway may shed light on the pathway for CX3CL1 to exert function. In a conclusion, our study comprehensively summarizes the potential role of CX3CL1 in clinical prognosis and immunotherapy, suggesting that CX3CL1 may represent a promising pharmacological treatment target of tumors.

Immunocyte Derived Exosomes: Insight into the Potential Chemo-immunotherapeutic Nanocarrier Targeting the Tumor Microenvironment

"Cancer" is a dreadful immune-pathological condition that is characterized by anti-inflammatory and tumorigenic responses, elicited by the infiltrating immune cells in the vicinity of an uncontrollably proliferative tumor in the tumor microenvironment (TME). The TME offers a conducive microenvironment that supports cancer cell survival by modulating the host immune defense. Recent advancement in exosomal research has shown exosomes, originating from immune cells as well as the cancer cells, have immense potential for suppressing cancer progression and survival in the TME. Additionally, exosomes, irrespective of their diverse sources, have been reported to be efficient nanocarriers for cancer therapeutics with the ability for targeted delivery due to their biogenic nature, ease of cellular uptake, and scope for functionalization with biomolecules like peptides, aptamers, targeting ligands, etc. Immune cell-derived exosomes per se have been found efficacious against cancer owing to their immune-stimulant properties (in either naive or antigen primed form) even without loading any of cancer therapeutics or targeting ligand conjugation. Nevertheless, exosomes are being primarily explored as nanovesicular carriers for therapeutic molecules with different loading and targeting strategies, and the synergism between immunotherapeutic behavior of exosomes and the anticancer effect of the therapeutic molecules is yet to be explored. Hence, this review focuses specifically on the possible strategies to modulate the immunological nature of the source immune cells to obtain immune stimulant exosomes and bring these into the spotlight as chemo-immunotherapeutic nanovesicles, that can easily target and modulate the TME.

The Dynamic Entropy of Tumor Immune Infiltrates: The Impact of Recirculation, Antigen-Specific Interactions, and Retention on T Cells in Tumors

Analysis of tumor infiltration using conventional methods reveals a snapshot view of lymphocyte interactions with the tumor environment. However, lymphocytes have the unique capacity for continued recirculation, exploring varied tissues for the presence of cognate antigens according to inflammatory triggers and chemokine gradients. We discuss the role of the inflammatory and cellular makeup of the tumor environment, as well as antigen expressed by cancer cells or cross-presented by stromal antigen presenting cells, on recirculation kinetics of T cells. We aim to discuss how current cancer therapies may manipulate lymphocyte recirculation versus retention to impact lymphocyte exclusion in the tumor.

CC Chemokines in a Tumor: A Review of Pro-Cancer and Anti-Cancer Properties of the Ligands of Receptors CCR1, CCR2, CCR3, and CCR4

CC chemokines, a subfamily of 27 chemotactic cytokines, are a component of intercellular communication, which is crucial for the functioning of the tumor microenvironment. Although many individual chemokines have been well researched, there has been no comprehensive review presenting the role of all known human CC chemokines in the hallmarks of cancer, and this paper aims at filling this gap. The first part of this review discusses the importance of CCL1, CCL3, CCL4, CCL5, CCL18, CCL19, CCL20, CCL21, CCL25, CCL27, and CCL28 in cancer. Here, we discuss the significance of CCL2 (MCP-1), CCL7, CCL8, CCL11, CCL13, CCL14, CCL15, CCL16, CCL17, CCL22, CCL23, CCL24, and CCL26. The presentation of each chemokine includes its physiological function and then the role in tumor, including proliferation, drug resistance, migration, invasion, and organ-specific metastasis of tumor cells, as well as the effects on angiogenesis and lymphangiogenesis. We also discuss the effects of each CC chemokine on the recruitment of cancer-associated cells to the tumor niche (eosinophils, myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), regulatory T cells (T_reg)). On the other hand, we also present the anti-cancer properties of CC chemokines, consisting in the recruitment of tumor-infiltrating lymphocytes (TIL).

Applications of chemokines as adjuvants for vaccine immunotherapy

Vaccinations are expected to aid in building immunity against pathogens. This objective often requires the addition of an adjuvant with certain vaccine formulations containing weakly immunogenic antigens. Adjuvants can improve antigen processing, presentation, and recognition, thereby improving the immunogenicity of a vaccine by simulating and eliciting an immune response. Chemokines are a group of small chemoattractant proteins that are essential regulators of the immune system. They are involved in almost every aspect of tumorigenesis, antitumor immunity, and antimicrobial activity and also play a critical role in regulating innate and adaptive immune responses. More recently, chemokines have been used as vaccine adjuvants due to their ability to modulate lymphocyte development, priming and effector functions, and enhance protective immunity. Chemokines that are produced naturally by the body's own immune system could serve as potentially safer and more reliable adjuvant options versus synthetic adjuvants. This review will primarily focus on chemokines and their immunomodulatory activities against various infectious diseases and cancers.

High CCL27 immunoreactivity in 'supratumoral' epidermis correlates with better prognosis in patients with cutaneous malignant melanoma

AIMS

It has been proposed that the expression of chemokines and chemokine receptors by melanoma cells may have a role in tumour immune escape. Chemokine CCL27 is reported to be expressed specifically on the epidermal keratinocytes. The implication of CCL27 in cutaneous melanomas is currently unresolved. It has been suggested that CCL27 expression in melanomas can induce antitumoral immunity, and that CCL27 may suppress tumour growth probably due to the local lymphocyte recruitment.

METHODS

We studied CCL27 chemokine expression in three different concentric epidermal areas covering the primary cutaneous melanoma in patients with a long clinical follow-up. Our study included 91 cases of primary melanomas of the skin diagnosed during the 10-year period 1992-2002, and a minimum clinical follow-up of 10 years.

RESULTS

We evaluated three different concentric and easily reproducible areas in the epidermis: the area covering melanoma (which we called 'supratumoral'), the area adjacent to the tumour ('peritumoral') and the most peripheral epidermal area ('peripheral'). Only CCL27 expression in supratumoral epidermis correlated with clinical outcome.

CONCLUSIONS

Our study showed that a higher immunostaining of CCL27 in supratumoral epidermis is associated with longer progression-free interval and melanoma-specific survival.

Chemokine Receptor Signaling and the Hallmarks of Cancer

The chemokines are a family of chemotactic cytokines that mediate their activity by acting on seven-transmembrane-spanning G protein-coupled receptors. Both the ability of the chemokines and their receptors to form homo- and heterodimers and the promiscuity of the chemokine-chemokine receptor interaction endow this protein family with enormous signaling plasticity and complexity that are not fully understood at present. Chemokines were initially identified as essential regulators of homeostatic and inflammatory trafficking of innate and adaptive leucocytes from lymphoid organs to tissues. Chemokines also mediate the host response to cancer. Nevertheless, chemokine function in this response is not limited to regulating leucocyte infiltration into the tumor microenvironment. It is now known that chemokines and their receptors influence most-if not all-hallmark processes of cancer; they act on both neoplastic and untransformed cells in the tumor microenvironment, including fibroblasts, endothelial cells (blood and lymphatic), bone marrow-derived stem cells, and, obviously, infiltrating leucocytes. This review begins with an overview of chemokine and chemokine receptor structure, to better define how chemokines affect the proliferation, survival, stemness, and metastatic potential of neoplastic cells. We also examine the main mechanisms by which chemokines regulate tumor angiogenesis and immune cell infiltration, emphasizing the pro- and antitumorigenic activity of this protein superfamily in these interrelated processes.

Fusion cytokine IL-2-GMCSF enhances anticancer immune responses through promoting cell-cell interactions

Background

Potent antitumor responses can be induced through cytokine immunotherapy. Interleukin (IL)-2 and granulocyte–macrophage colony-stimulating factor (GM-CSF) are among the most effective cytokines to induce tumor-specific systemic immune responses and can act synergistically. To overcome the limitations of combined use of these two cytokines, we have constructed an IL2-GMCSF fusion protein and characterized its antitumor effects in this study.

Methods

The expression of IL-2 receptor and GM-CSF receptor of cell lines were detected with quantitative real-time PCR. On this basis, the bioactivities of IL2-GMCSF, especially effects on DC2.4 cells were assayed. Another function of IL2-GMCSF—bridge two types of cells—was assessed by cell contact counting and cytotoxicity assays. The anti-tumor activity in vivo of IL2-GMCSF was evaluated in the melanoma model. The statistical significance among treatment groups were determined by One-Way ANOVA.

Results

The fusion protein IL2-GMCSF maintained the activities of IL-2 and GM-CSF, and could significantly promote DC2.4 cell activities, including phagocytosis, proliferation and cytokine secretion. In addition to the inherent cytokine activity, IL2-GMCSF bridges direct cell–cell interactions and enhances splenocyte killing efficacy against multiple tumor cell lines in vitro. Co-injection of IL2-GMCSF and inactivated B16F10 mouse melanoma cells induced complete immunoprotective responses in about 30 % of mice.

Conclusion

These results suggested that IL2-GMCSF can efficiently regulate immune responses against tumors. Furthermore, as the bridging effect relies on both IL-2R and GM-CSFR and promotes interactions between immune and tumor cells, IL2-GMCSF may be utilized as a useful tool for dissecting specific immune responses for future clinical applications.

Exosomes from Dendritic Cells Loaded with Chaperone-Rich Cell Lysates Elicit a Potent T Cell Immune Response Against Intracranial Glioma in Mice

Chaperone-rich cell lysates (CRCLs) may play an important role in the development of anti-tumor vaccines. Tumor-derived CRCLs have been reported to activate dendritic cells (DCs) to elicit potent anti-tumor activity. However, the role of DC-derived exosomes (DEXs) secreted from DCs loaded with CRCLs in the treatment of tumors has not been clearly determined. In the present study, DEXs were generated from DCs loaded with CRCLs derived from GL261 glioma cells. These DEXs, designated DEX (CRCL-GL261), were then used to treat DCs to create DEX (CRCL-GL261)-DCs. The DEX (CRCL-GL261)-DCs were found to promote cell proliferation and cytotoxic T lymphocyte (CTL) activity of CD4(+) and CD8(+) T cells in vitro compared with DEX (GL261)-DCs, which were loaded with DEXs derived from DCs loaded with GL261 tumor cell lysates. DEX (CRCL-GL261)-DCs significantly prolonged the survival of mice with tumors and inhibited tumor growth in vivo. In addition, DEX (CRCL-GL261)-DCs induced enhanced T cell infiltration in intracranial glioma tissues compared with other treatments. DEX (CRCL-GL261)-DCs induced strong production of anti-tumor cytokines, including interleukin-2 and interferon-γ. Moreover, depletion of CD4(+) and CD8(+) T cells significantly impaired the anti-tumor effect of DEX (CRCL-GL261)-DCs. Finally, DEX (CRCL-GL261)-DCs were found to negatively regulate Casitas B cell lineage lymphoma (Cbl)-b and c-Cbl signaling, leading to the activation of phosphatidyl inositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) signaling in T cells. In summary, we present evidence that DEX (CRCL-GL261)-DCs induce more potent and effective anti-tumor T cell immune responses and delineate the underlying mechanism by which DEX (CRCL-GL261)-DCs exerted their anti-tumor activity through modulating Cbl-b and c-Cbl signaling. These results provide novel and promising insight for the development of an anti-tumor vaccine.

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

The chemokine CCL21 is a potent chemoattractant for T cells and dendritic cells. IL-15 elicits powerful antitumor immune responses through the stimulation of natural killer cells. We constructed a CCL21/IL-15-expressing adenovirus (Ad-CCL21-IL-15) and evaluated its antitumor effects in vitro and in vivo. We found that the intratumoral injection of Ad-CCL21-IL-15 into murine colon carcinomas significantly inhibited tumor growth. Splenocytes from mice treated with Ad-CCL21-IL-15 developed tumor-specific cytotoxic T cells and were protected from subsequent challenges with tumor cells. This study indicates that providing cancer therapy by combining CCL21 and IL-15 can induce antitumor immune responses and is an effective strategy for cancer immunotherapy.

TLR4 is essential for dendritic cell activation and anti-tumor T-cell response enhancement by DAMPs released from chemically stressed cancer cells

The combination of immunotherapy and chemotherapy is regarded as a promising approach for the treatment of certain types of cancer. However, the underlying mechanisms need to be fully investigated to guide the design of more efficient protocols for cancer chemoimmunotherapy. It is well known that danger-associated molecular patterns (DAMPs) can activate immune cells, including dendritic cells (DCs), via Toll-like receptors (TLRs); however, the role of DAMPs released from chemical drug-treated tumor cells in the activation of the immune response needs to be further elucidated. Here, we found that colorectal cancer (CRC) cells treated with oxaliplatin (OXA) and/or 5-fluorouracil (5-Fu) released high levels of high-mobility group box 1 (HMGB1) and heat shock protein 70 (HSP70). After OXA/5-Fu therapy, the sera of CRC patients also exhibited increased levels of HMGB1 and HSP70, both of which are well-known DAMPs. The supernatants of dying CRC cells treated with OXA/5-Fu promoted mouse and human DC maturation, with upregulation of HLA-DR, CD80 and CD86 expression and enhancement of IL-1β, TNF-α, MIP-1α, MIP-1β, RANTES and IP-10 production. Vaccines composed of DCs pulsed with the supernatants of chemically stressed CRC cells induced a more significant IFN-γ-producing Th1 response both in vitro and in vivo. However, the supernatants of chemically stressed CRC cells failed to induce phenotypic maturation and cytokine production in TLR4-deficient DCs, indicating an essential role of TLR4 in DAMP-induced DC maturation and activation. Furthermore, pulsing with the supernatants of chemically stressed CRC cells did not efficiently induce an IFN-γ-producing Th1 response in TLR4-deficient DCs. Collectively, these results demonstrate that DAMPs released from chemically stressed cancer cells can activate DCs via TLR4 and enhance the induction of an anti-tumor T-cell immune response, delineating a clinically relevant immuno-adjuvant pathway triggered by DAMPs.

Exosomes derived from Rab27a‑overexpressing tumor cells elicit efficient induction of antitumor immunity

Lung cancer is the leading cause of mortality worldwide. However, there is a lack of effective therapeutic strategies. Currently, tumor immunotherapy based on exosomes, which are secreted by a variety of cell types including tumor cells, has drawn particular attention and are suggested to have the potential for exploitation in tumor therapy. Nevertheless, the therapeutic efficacy mediated via tumor cell-derived exosomes is not satisfactory. Rab27a, one of the Rab family of small GTPases, has been suggested to be important in exosome secretion. Thus, the purpose of the present study was to examine whether exosomes derived from Rab27a‑overexpressing cells elicited more potent antitumor immunity. A Rab27a‑overexpressing line was established via transfection of a Rab27a overexpression vector into the human non-small-cell lung cancer cell line, A549. Exosomes were isolated and the typical exosomal protein markers, CD9, CD63, heat shock protein (Hsp) 70 and Hsp90, were found to be enriched in the exosomes derived from Rab27a‑overexpressing cells. Subsequently, these exosomes were demonstrated to be capable of upregulating major histocompatibility complex class II molecules as well as the co-stimulatory molecules CD80 and CD86 on dendritic cells (DCs), suggesting that more potent maturation of DCs was induced. Furthermore, DCs loaded with exosomes derived from Rab27-overexpressing cells significantly promoted CD4+ T cell proliferation in vitro. In addition, in vivo immunization of exosomes derived from Rab27a‑overexpressing cells inhibited tumor growth in a mouse model. It was also demonstrated that splenocytes from mice immunized with exosomes derived from Rab27-overexpressing cells expressed high levels of type I cytokines, including IL-2 and IFN-γ, which are important in the regulation of cell-mediated antitumor immunity. Collectively, it was demonstrated that exosomes derived from Rab27a‑overexpressing cancer cells elicited more potent antitumor immune effects, which may provide novel insights for the development of efficient exosome-based cancer vaccines.

Alocasia cucullata exhibits strong antitumor effect in vivo by activating antitumor immunity

Chinese herbal medicines have long been used to treat various illnesses by modulating the human immune response. In this study, we investigate the immuno-modulating effect and antitumor activity of Alocasia Cucullata (AC), a Chinese herb traditionally used to treat infection and cancer. We found that the whole water extract of AC roots could significantly attenuate tumor growth in mouse tumor models. The median survival time of the AC-treated mice was 43 days, 16 days longer than that of the control group. Moreover, the AC-treated mice showed substantially higher induction of key antitumor cytokines, such as IL-2, IFN-γ, and TNF-α, indicating that AC may exert antitumor effect by activating antitumor immunity. To further pinpoint the cellular and molecular mechanism of AC, we studied the dose response of a human monocytic cell line, THP-1, to the whole water extract of AC. Treatment of the AC extract significantly induced THP-1 differentiation into macrophage-like cells and the differentiated THP-1 showed expression of specific macrophage surface markers, such as CD11b and CD14, as well as productions of antitumor cytokines, e.g. IFN-γ and TNF-α. Our data thus point to AC as potentially a new, alternative immuno-modulating herbal remedy for anticancer treatment.

Chemokine-based immunotherapy: delivery systems and combination therapies

A major role of chemokines is to mediate leukocyte migration through interaction with G-protein-coupled receptors. Various delivery systems have been developed to utilize the chemokine properties for combating disease. Viral and mutant viral vectors expressing chemokines, genetically modified dendritic cells with chemokine or chemokine receptors, engineered chemokine-expressing tumor cells and pDNA encoding chemokines are among these methods. Another approach for inducing a targeted immune response is fusion of a targeting antibody or antibody fragment to a chemokine. In addition, chemokines induce more effective antitumor immunity when used as adjuvants. In this regard, chemokines are codelivered along with antigens or fused as a targeting unit with antigenic moieties. In this review, several chemokines with their role in inducing immune response against different diseases are discussed, with a major emphasis on cancer.

The pros and cons of chemokines in tumor immunology

Innate and adaptive immune cells can intervene during tumor progression at different stages including initiation, angiogenesis, local spreading and distant metastasis formation. The net effect can be favorable or detrimental to tumor development, depending on the composition and activation status of the immune infiltrate. Chemokines can determine the distribution of immune cells in the tumor microenvironment and also affect stroma composition. Here we consider how a complex network of chemokines plays a key role in dictating the fate of a tumor. Although the field is in its infancy, we also highlight how targeting chemokines offers a tool to modulate the tumor environment with the aim of enhancing immune-mediated rejection of cancer.

Tong Luo Jiu Nao injection, a traditional Chinese medicinal preparation, inhibits MIP-1β expression in brain microvascular endothelial cells injured by oxygen-glucose deprivation

ETHNOPHARMACOLOGICAL RELEVANCE

Tong Luo Jiu Nao injection (TLJN), a modern Chinese formula based on Traditional Chinese Medicine theory, has been used to treat ischemic stroke and vascular dementia. TLJN belongs to the ethnopharmacological family of medicines.

AIM OF THE STUDY

To investigate the protective effect of TLJN on oxygen-glucose deprivation (OGD) induced-injury of brain microvascular endothelial cells (BMECs).

MATERIALS AND METHODS

The model of OGD was established in the primarily cultured BMECs. TLJN was added to the OGD-injured BMECs for 6h. A series of assays were used to detect the effects of TLJN on: (i) MIP-1β content in BMECs conditioned media (CM) by ELISA; (ii) MIP-1β protein expression in BMECs by western blotting and immunocytochemistry; (iii) the expression of CCR5, receptor of MIP-1β, in BMECs by western blotting; (iv) the proliferative activity of microglial cells via the Cell Counting Kit-8 (CCK-8).

RESULTS

Our results showed that the OGD-injured BMECs presented with large amounts of secretion and expression of MIP-1β and up-regulation of CCR5. Also, the CM of OGD-injured BMECs remarkably increased the proliferative activity of microglial cells. The TLJN-treated BMECs exhibited a reduction of MIP-1β content in BMECs-CM and a down-regulation of MIP-1β and CCR5 expression. In addition, an inhibitory effect of CM of OGD-injured plus TLJN injection-treated BMECs on microglial proliferation was also found.

CONCLUSION

TLJN reduced the expression of MIP-1β and CCR5 in OGD-injured BMECs, and the CM of OGD-injured plus TLJN injection-treated BMECs inhibited the proliferative activity of microglial cells, suggesting the therapeutic potential of TLJN on ischemic cerebral vascular disease.

Rapid determination of serological cytokine biomarkers for hepatitis B virus-related hepatocellular carcinoma using antibody microarrays

Hepatocellular carcinoma (HCC) is one of the most frequent tumors worldwide with an increasing incidence. The exploration of biomarkers for HCC is one of the main aims for improving the efficacy of diagnosis and treatment. The microarray technology provides a high-throughput platform for parallel exploration of biomarkers for clinics. In this study, we used antibody microarrays to screen the novel cytokine biomarkers of hepatitis B virus (HBV)-related HCC. Cytokine-secreting patterns in sera were determined from 109 cases including 43 HBV-related HCC patients, 33 chronic hepatitis B patients, and 33 normal controls by RayBio Biotin label-based human antibody array. The correlation analysis was performed with conventional clinical diagnostic biomarkers, including serum alanine aminotransferase, alpha-fetoprotein (AFP) and hepatitis B surface antigen. Our results showed that in HBV-related HCC group, which had the highest percentage of AFP positive (>20 ng/ml) ratio, six cytokines were found differentially expressed in HCC patients (P < 0.05), compared with either normal controls or chronic hepatitis B group. Two macrophage-related cytokines, macrophage-derived chemokine (MDC) and macrophage-stimulating protein α (MSPα), displayed significant difference in the HCC group. Furthermore, an HCC diagnostic model for prediction was constructed, by which the combination of MDC and MSPα together with AFP had improved the diagnostic sensitivity from 60% (AFP alone) to 73.2% with similar specificity. Our results suggested that MDC and MSPα screened by antibody microarrays might serve as novel cytokines biomarkers for potential auxiliary diagnosis of HBV-related HCC.

Improving survival rates in two models of spontaneous postoperative metastasis in mice by combined administration of a beta-adrenergic antagonist and a cyclooxygenase-2 inhibitor

Clinical practice does not consider perioperative paracrine and neuroendocrine stress responses as risk factors for cancer recurrence, although recent animal studies provided supportive evidence. Suggested mechanisms include the effects of stress-hormones on tumor cells and on host physiology. In this study, in mice undergoing primary tumor excision, we tested the survival-enhancing potential of perioperative blockade of catecholamines and prostaglandins, and studied potential mediating mechanisms. C57BL/6J mice were inoculated intrafootpad with syngeneic B16F10.9-melanoma or Lewis lung carcinoma, and the paw was amputated when a developing tumor exceeded 100 microl. The clinically used beta-adrenergic antagonist propranolol, and/or the cyclooxygenase-2 inhibitor etodolac, were administered once before amputation, and recurrence-free survival was monitored. In different studies, NK cytotoxicity, leukocytes' molecular functional markers, and vascular endothelial growth factor secretion by tumor cells were studied in the context of surgery and drug treatments. The findings indicated that the combination of propranolol and etodolac, but neither drug alone, significantly and markedly improved survival rates in both tumor models, and was as effective as established immunostimulatory agents (IL-12 and polyinosinic-polycytiylic acid). Surgery markedly reduced NK cytotoxicity and NK cell expression of Fas ligand and CD11a, reduced all circulating lymphocyte-subtype concentrations, and increased corticosterone levels. Propranolol and etodolac administration counteracted these perturbations. B16 and 3LL secreted vascular endothelial growth factor in vitro, but secretion was not affected by catecholamine agonists, prostaglandins, corticosterone, propranolol, or etodolac. Overall, propranolol and etodolac administration, which could be applied perioperatively in most cancer patients with minimal risk and low cost, has counteracted several immunologic and endocrinologic perturbations and improved recurrence-free survival rates in mice undergoing primary tumor excision.

CXCR6/CXCL16 functions as a regulator in metastasis and progression of cancer

Metastasis is considered the obvious mark for most aggressive cancers. However, little is known about the molecular mechanism of the regulation of cancer metastasis. Recent evidence increasingly suggests that the interaction between chemokines and chemokine receptors is pivotal in the process of metastasis. The chemokine receptor CXCR4 and its ligand CXCL12, for example, have been reported to play a vital role in cancer metastasis. Another chemokine and chemokine receptor pair, the CXCL16/CXCR6 axis, has been studied by several independent research groups. Here, we summarize recent advances in our knowledge of the function of CXC chemokine receptor CXCR6 and its ligand CXCL16 in regulating metastasis and invasion of cancer. CXCR6 and CXCL16 are up-regulated in multiple cancer tissue types and cancer cell lines relative to normal tissues and cell lines. In addition, both CXCR6 and CXCL16 levels increase as tumor malignancy increases. Trans-membranous CXCL16 chemokine reduces proliferation while soluble CXCL16 chemokine enhances proliferation and migration. TM-CXCL16 functions as an inducer for lymphocyte build-up around tumor sites. High trans-membranous CXCL16 expression correlates with a good prognosis. Moreover, the Akt/mTOR signal pathway is involved in activating the CXCR6/CXCL16 axis. These findings suggest multiple opportunities for blocking the CXCR6/CXCL16 axis and the Akt/mTOR signal pathway in novel cancer therapies.

Modulating the expression of IFN regulatory factor 8 alters the protumorigenic behavior of CD11b+Gr-1+ myeloid cells

CD11b(+)Gr-1(+)-expressing cells, termed myeloid-derived suppressor cells, can mediate immunosuppression and tumor progression. However, the intrinsic molecular events that drive their protumorigenic behavior remain to be elucidated. Although CD11b(+)Gr-1(+) cells exist at low frequencies in normal mice, it also remains unresolved whether they are biologically distinct from those of tumor-bearing hosts. These objectives were investigated using CD11b(+)Gr-1(+) cells from both implantable (4T1) and autochthonous (mouse mammary tumor virus-polyomavirus middle T Ag (MMTV-PyMT)) mouse models of mammary carcinoma. Limited variation was observed in the expression of markers associated with immunoregulation between CD11b(+)Gr-1(+) cells of both tumor models, as well as with their respective controls (Cnt). Despite limited differences in phenotype, tumor-induced CD11b(+)Gr-1(+) cells were found to produce a more immunosuppressive cytokine profile than that observed by Cnt CD11b(+)Gr-1(+) cells. Furthermore, when admixed with tumor cells, CD11b(+)Gr-1(+) cells from tumor-bearing mice significantly enhanced neoplastic growth compared with counterpart cells from Cnt mice. However, the protumorigenic behavior of these tumor-induced CD11b(+)Gr-1(+) cells was significantly diminished when the expression of IFN regulatory factor 8, a key myeloid-associated transcription factor, was enhanced. The loss of this protumorigenic effect occurred independently of the host immune system and correlated with a CD11b(+)Gr-1(+) cytokine/chemokine production pattern that resembled cells from nontumor-bearing Cnt mice. Overall, our data indicate that 1) tumor-induced CD11b(+)Gr-1(+) cells from both cancer models were phenotypically similar, but biologically distinct from their nontumor-bearing counterparts and 2) modulation of IFN regulatory factor 8 levels in tumor-induced CD11b(+)Gr-1(+) cells can significantly abrogate their protumorigenic behavior, which may have important implications for cancer therapy.

Attraction and activation of dendritic cells at the site of tumor elicits potent antitumor immunity

Tumor cells harbor unique genetic mutations, which lead to the generation of immunologically foreign antigenic peptide repertoire with the potential to induce individual tumor-specific immune responses. Here, we developed an in situ tumor vaccine with the ability to elicit antitumor immunity. This vaccine comprised an E1B-deleted oncolytic adenovirus expressing beta-defensin-2 (Ad-BD2-E1A) for releasing tumor antigens, recruiting and activating plasmacytoid dendritic cells (pDCs). Intratumoral injections of Ad-BD2-E1A vaccine inhibited primary breast tumor growth and blocked naturally occurring metastasis in mice. Ad-BD2-E1A vaccination induced potent tumor-specific T-cell responses. Splenic and intratumoral DCs isolated from Ad-BD2-E1A-immunized mice were able to stimulate or promote the differentiation of naive T cells into tumor-specific cytotoxic T cells. We further found that the increased numbers of mature CD45RA(+)CD8alpha(+)CD40(+) pDCs infiltrated into Ad-BD2-E1A-treated tumors. The antitumor effect of Ad-BD2-E1A vaccination was abrogated in toll-like receptor 4 (TLR4) deficient mice, suggesting the critical role of TLR4 in the induction of antitumor immunity by Ad-BD2-E1A. The results of this study indicate that in situ vaccination with the oncolytic BD2-expressing adenovirus preferentially attracts pDCs and promotes their maturation, and thus elicits potent tumor-specific immunity. This vaccine represents an attractive therapeutic strategy for the induction of individualized antitumor immunity.

NK cells are migrated and indispensable in the anti-tumor activity induced by CCL27 gene therapy

Natural killer (NK) cells have been demonstrated could play an important role in the treatment of a number of tumors in mice. In the present study, chemokine CCL27, which be considered only selectively chemoattracts cutaneous lymphocyte antigen positive memory T cells and Langerhans cells, firstly demonstrated that it could induce the accumulation of NK cells into tumor by the intratumoral injection of CCL27-encoding fiber-mutant vector, AdRGD-CCL27. Experiments using spleen cell fractionation and RT-PCR showed CCL27 receptor, mCCR10, was strongly expressed in NK cells, suggesting the accumulation of NK cells in tumor was attributed to chemoattractant activity of CCL27 itself. Moreover, the combination of AdRGD-CCL27 and AdRGD-IL-12 induced the synergistic anti-tumor activity via NK-dependent manner and induced more NK cells infiltration into tumor nodule than that induced by AdRGD-CCL27 alone or AdRGD-IL-12 alone.

Combination of two fiber-mutant adenovirus vectors, one encoding the chemokine FKN and another encoding cytokine interleukin 12, elicits notably enhanced anti-tumor responses

For achieving optimal cancer immunotherapy, it is anticipated that both the activation and infiltration of immune cells into tumor are indispensable. In the present study, fiber-mutant adenovirus vectors (Ad) encoding chemokine FKN, (AdRGD-FKN), and cytokine interleukin 12, (AdRGD-IL-12), were constructed. The in vivo gene expression of AdRGD was confirmed and the combination of both FKN and IL-12 encoding Ad elicited synergistic anti-tumor activity in ovarian carcinoma, which induced tumor regression in all tumor-bearing mice, while using FKN alone did not show notable tumor-suppressive effect. The treatment with both IL-12 and FKN induced long-term specific immunity against OV-HM tumors in tumor-rejected mice. The results of immunohistochemical staining for CD3+ and perforin-positive cells suggested that the failure of using FKN alone was because of the inactivation of infiltrated immune cells. In contrast, cotransduction with IL-12 and FKN could induce more activated tumor-infiltrating immune cells than that transducted with FKN or IL-12 alone. The results indicated that using both chemokine and cytokine might be a powerful tool and a promising way for effective cancer immunotherapy.

Increased expression of fractalkine is correlated with a better prognosis and an increased number of both CD8+ T cells and natural killer cells in gastric adenocarcinoma

BACKGROUND

Fractalkine (CX3CL1) is the only CX3C chemokine that can chemoattract natural killer (NK) cells, CD8+ T cells, monocytes, and dendritic cells. Although experimental studies have demonstrated that Fractalkine expression by tumor cells is related to the infiltrating lymphocytes and initiates antitumor immunity, the clinical significance of Fractalkine remains to be elucidated in gastric adenocarcinoma.

METHODS

Tissue sections from 158 patients with curatively resected T2 or T3 gastric adenocarcinoma were immunohistochemically stained for Fractalkine. Furthermore, to evaluate CD8+ T cells and NK cells infiltration, antibodies to CD8 and CD57 protein were respectively used for immunohistochemistry.

RESULTS

A significant direct correlation was observed between the Fractalkine scores and the number of CD8+ T cells and NK cells using the Spearman rank correlation coefficient test (P = .0080, .0031, respectively). Furthermore, the high Fractalkine expression group (n = 67) showed a significantly better prognosis than the low Fractalkine expression group (n = 91) regarding the disease-free survival (P = .0016). In a multivariate analysis, the Fractalkine expression was identified as one of the independent prognosticators for disease-free survival (risk ratio, 2.5; P = .0147).

CONCLUSIONS

These data suggest that the expression of Fractalkine by tumor cells enhances the recruitment of CD8+ T cells and NK cells and induces both innate and adaptive immunity, thereby yielding a better prognosis in gastric adenocarcinoma. Fractalkine is a new independent predictor of the prognosis and can be a novel candidate for development of a more effective therapeutic strategy for gastric adenocarcinomas.

Immune cell recruitment and cell-based system for cancer therapy

Immune cells, such as cytotoxic T lymphocytes, natural killer cells, B cells, and dendritic cells, have a central role in cancer immunotherapy. Conventional studies of cancer immunotherapy have focused mainly on the search for an efficient means to prime/activate tumor-associated antigen-specific immunity. A systematic understanding of the molecular basis of the trafficking and biodistribution of immune cells, however, is important for the development of more efficacious cancer immunotherapies. It is well established that the basis and premise of immunotherapy is the accumulation of effective immune cells in tumor tissues. Therefore, it is crucial to control the distribution of immune cells to optimize cancer immunotherapy. Recent characterization of various chemokines and chemokine receptors in the immune system has increased our knowledge of the regulatory mechanisms of the immune response and tolerance based on immune cell localization. Here, we review the immune cell recruitment and cell-based systems that can potentially control the systemic pharmacokinetics of immune cells and, in particular, focus on cell migrating molecules, i.e., chemokines, and their receptors, and their use in cancer immunotherapy.

Macrophage-derived chemokine in malignant and tuberculous pleural effusions

BACKGROUND AND OBJECTIVES

Macrophage-derived chemokine (MDC/CCL22) is recognized as a T-helper (Th) 2-type chemokine. Both malignant and tuberculous pleural effusions are typically lymphocytic pleural effusions. Tuberculous pleural effusions have a more polarized Th1 reaction than malignant effusions, which are predominantly Th2 in nature. The aim of this study was to compare the levels of MDC in malignant pleural effusions with those in tuberculous pleural effusions to help delineate the role of MDC in Th2 versus Th1 effusions.

METHODS

Forty-three patients with pleural effusions (32 malignant, 11 tuberculous) were studied. The concentration of MDC in the pleural effusion was measured by ELISA.

RESULTS

The median concentration of MDC was lower in malignant pleural effusions than in tuberculous pleural effusions (P < 0.005).

CONCLUSIONS

MDC has been reported to both promote and suppress antitumour immunity. The low concentration of MDC in malignant effusions is likely to minimise its antitumour activity but the precise role of MDC in malignant and tuberculous effusions needs to be investigated further.

Gene therapy with CX3CL1/Fractalkine induces antitumor immunity to regress effectively mouse hepatocellular carcinoma

CX3CL1/Fractalkine(FK), a chemokine existing in both secreted and membrane anchored form, was reported to induce suppressive activities in tumor models. Here, we demonstrate for the first time the antitumor effects of FK in murine hepatocellular carcinoma (HCC) by constructing a FK eukaryotic expression vector (pIRES-FK) and transferring it into such tumor cells. Tumor rejection experiments were performed by injecting FK gene-modified murine HCC cell line (MM45T.Li) into immunocompetent mice, which significantly inhibited tumorigenicity or growth of MM45T.Li-FK cells. Immunohistochemistry examination and fluorescence-activated cell sorting analyses revealed both CD4+ and CD8+ T cells infiltration within the tumor together with a marked increase of these cells in the peripheral blood. Splenic lymphocyte from mice treated with MM45T.Li-FK were effective in the induction of tumor-specific cytotoxic T cells. We also observed an increased production of IL-2 and IFN-gamma in MM45T.Li-FK tumor tissue. Our results suggest that transfer of the FK gene into tumor cells could elicit a specific antitumor immunity capable of inhibiting tumor growth which lead to increased survival of tumor-bearing hosts. FK should be considered as a chemokine suitable for cancer immunoprevention or gene therapy.

More than chemotaxis: a new anti-tumor DC vaccine modified by rAAV2-SLC

Secondary lymphoid tissue chemokine (SLC) is strongly expressed in secondary lymphoid organs. Its ability to facilitate chemotaxis of both dendritic cells (DC) and T cells makes it a promising candidate for cancer therapy. In this study, we modified a BMDC vaccine by incorporating the SLC mature peptide gene. The efficacy of this vaccine was evaluated using a mouse hepatocellular carcinoma (HCC) model, with rAAV2 as the gene delivery vector. The rAAV2 encoding SLC (rAAV2-SLC) transfected immature BMDCs at high efficiency and the anti-tumor effects of SLC gene modified BMDCs (rAAV2-SLC/BMDC) were evaluated. In addition, rAAV2-SLC/BMDC vaccine injected directly into tumors attracted more CD4(+) and CD8(+) T lymphocytes into tumors and showed stronger anti-tumor effects than footpad delivery. Moreover, we found that the phenotypic expression of MHC II, the secretion of IL-12 and IFN-gamma, and T cell stimulation were increased in vitro following treatment with rAAV2-SLC/BMDC vaccine and these responses were inhibited by PTX. In vivo, PTX also inhibited the anti-tumor effects of the vaccine. The results suggest that the expression of SLC by rAAV2-SLC/BMDC plays more than a chemotactic role in anti-tumor responses, thus these studies further demonstrate that SLC has potential to be valuable in cancer therapy.

Antitumor effects of the MIG and IP-10 genes transferred with poly [D,L-2,4-diaminobutyric acid] on murine neuroblastoma

The number of tumor-infiltrating lymphocytes is known to be related to outcomes in patients with a variety of malignancies. Interferon (IFN) gamma-inducible protein-10 (IP-10) and monokine induced by IFNgamma (MIG) have chemotactic effects on activated T lymphocytes and natural killer (NK) cells. The aim of this study was to evaluate the antitumor effects of exogenous expression of the MIG and IP-10 genes delivered to solid tumors by poly [D,L-2,4-diaminobutyric acid] (PDBA). The murine MIG and IP-10 genes were transfected into mouse neuroblastoma cells with PDBA. MIG and IP-10 levels in supernatants of transfected cells were measured by enzyme-linked immunosorbent assay. The chemotactic activities of MIG and IP-10 in the supernatants of cell cultures were measured by chemotaxis assay. Tumors were injected in vivo with PDBA/pmMIGColon, two colonsIP-10 complexes to evaluate the effects of these genes on tumor volume and survival time of mice. Transfected PDBA/pmMIGColon, two colonsIP-10 complexes produced MIG and IP-10 protein in vitro. MIG and IP-10 proteins secreted into the culture medium showed chemotactic activity. MIG and IP-10 gene therapy with the PDBA system in vivo significantly inhibited tumor growth and prolonged survival time of mice. In conclusion, PDBA-mediated MIG and IP-10 gene therapy may be useful for treatment of solid tumors.

Clinical utilization of chemokines to combat cancer: the double-edged sword

Chemokines are a small group of related chemo-attractant peptides that play an essential role in the homeostatic maintenance of the immune system. They control the recruitment of cells needed for the induction and activation of innate and adaptive immune responses. However, tumors also utilize chemokines to actively progress and evade immunosurveillance. In fact, chemokines are involved directly or indirectly in almost every aspect of tumorigenesis. They mediate survival and metastatic spread of tumors, promote new blood vessel formation (neovascularization) and induce an immunosuppressive microenvironment via recruitment of immunosuppressive cells. As a result, a number of therapeutic strategies have been proposed to target almost every step of the chemokine/chemokine receptor involvement in tumors. Yet, despite occasional success stories, most of them appear to be ineffective or impractical, presumably due to 'nonspecific' harm of cells needed for the elimination of tumor escapees and maintenance of immunological memory. The strategy would only be effective if it also promoted antitumor adaptive immune responses capable of combating a residual disease and tumor relapse.

Expression of macrophage-derived chemokine (MDC)/CCL22 in human lung cancer

BACKGROUND

Ligands for CXCR3 chemokines [IFN-gamma-inducible protein of 10 kD (IP-10/CXCL10), monokine induced by IFN-gamma (Mig/CXCL9), IFN-inducible T cell alpha chemoattractant (I-TAC/CXCL11)] and those for CCR4 [macrophage-derived chemokine (MDC/CCL22), thymus- and activation-regulated chemokine (TARC/CCL17)] have been shown to play the central roles for T helper-cell recruitment into the tissues. To examine the role of these chemokines in tumor progression of lung cancer, we investigated their expression in human lung cancer tissues to determine the possible relationship between their expression and the prognosis of patients.

METHODS

Total RNA was prepared from lung cancer tissues of 40 patients (24 adenocarcinoma and 16 squamous cell carcinoma). We measured gene expression levels of chemokines (IP-10, Mig, I-TAC, MDC and TARC) by real-time quantitative RT-PCR.

RESULTS

Higher gene expression of MDC in lung cancer was significantly correlated with longer disease-free survival time and lower risk of recurrence after tumor resection. We could not find any significant relationship of IP-10, Mig, I-TAC and TARC gene expression with disease-free survival or lower risk of recurrence after surgery.

CONCLUSIONS

These results suggest that increased gene expression of MDC in tumor tissues may be a predictive marker for improving the prognosis of lung cancer.

Potential role of CCL27 and CCR10 expression in melanoma progression and immune escape

Aim of this study was to investigate using immunohistochemistry techniques the interrelation between T immunoreactive cells and the expression of CCR10 and its ligand CCL27 in 59 cutaneous melanocytic lesions. In malignant melanomas, T lymphocyte density was significantly decreased from thin melanomas to intermediate and thick ones (P<0.0005). CCR10 expression was found both in benign and malignant lesions and it was directly correlated with the Breslow depth (P=0.0298) and inversely with T lymphocyte density (P=0.0231). Moreover, cases with positive sentinel lymph node tended to have a higher CCR10 expression compared to cases with negative sentinel lymph node (P=0.0281). When CCR10 and CCL27 expression were evaluated together, CCR10-/CCL27-melanomas tended to have a higher mean density of CD3+ and CD8+ lymphocytes. Our results suggest that in human melanomas CCR10 and CCL27 may act to increase the ability of neoplastic cells to grow, invade tissue, disseminate to lymph nodes and to escape the host immune response.

Inflammatory chemokines in cancer growth and progression

Leukocyte infiltration is a cardinal feature of almost all cancers. Chemokines are generally responsible for eliciting local accumulation of inflammatory cells and they appear to play the same role in the formation of peri- and intra-tumoural infiltrates. Chronic inflammation predisposes to cancer formation and progression, and it is likely that the chemokine system contributes to this process. In part, this may be a consequence of its ability to attract mononuclear cells to cancer sites, where they provide growth or angiogenic factors that enhance cancer development. However, accumulating evidence also points to a direct effect of chemokines on cancer cells that express chemokine receptors. In particular, some chemokines can activate anti-apoptotic pathways in these cells. By either mechanism, tumour cells that secrete and/or respond to chemokines would have a selective advantage. This provides another example of cancer's ability to co-opt host systems in order to promote tumour progression.

Anti-tumor responses induced by chemokine CCL19 transfected into an ovarian carcinoma model via fiber-mutant adenovirus vector

Considerable attention has recently been paid to the application of chemokines to cancer immunotherapy because of their chemotactic affinity for a variety of immune cells and because several chemokines are strongly angiostatic. In the present study, the recombinant adenovirus vectors encoding chemokine CCL19 or XCL1 in an E1 cassette (AdRGD-mCCL19 and AdRGD-mXCL1) were developed. The constructed fiber-mutant adenovirus vector, which contained the integrin-targeting Arg-Gly-Asp (RGD) sequence in the fiber knob, notably enhanced the transfection efficiency to OV-HM ovarian carcinoma cells compared to that induced by conventional adenovirus vector. The results of an in vitro chemotaxis assay for chemokine-encoding vector demonstrated that both AdRGD-mCCL19 and AdRGD-mXCL1 could induce the migration of cells expressing specific chemokine receptors. Of the two chemokine-encoding vectors evaluated in vivo, AdRGD-mCCL19 showed significant tumor-suppressive activity in B6C3F1 mice via transduction into OV-HM cells, whereas XCL1 did not exhibit any notable anti-tumor effects, suggesting that CCL19 may be a candidate for cancer immunotherapy.

Migration of dendritic cell based cancer vaccines: in vivo veritas?

Ex vivo generated cancer vaccines based on dendritic cells (DCs) are currently applied in the clinic. The migration of DCs from the tissues to the lymph nodes is tightly controlled and involves many different mediators and their receptors. A recent study demonstrated that the rate of migration of antigen-bearing DCs in situ from the skin to the lymph node is 100-fold higher than previously estimated. The migration of ex vivo generated DCs is rather inefficient but can be improved by pre-conditioning of the vaccine injection site with inflammatory cytokines. An alternative approach that is currently being explored is to target tumor antigens directly to DCs in situ, thereby exploiting the intricate migratory capacity of DCs in vivo. Recent advances have been made in understanding DC migration in the context of DC-based vaccines.

Gene modification strategies to induce tumor immunity

The immune system provides an attractive option for use in cancer therapy. Our increasing understanding of the molecular events important in the generation of an effective immune response presents us with the opportunity to manipulate key genes to boost the immune response against cancer. Genetic modification is being employed to enhance a range of immune processes including antigen presentation, activation of specific T cells, and localization of immune effectors to tumors. In this review, we describe how many diverse cell types, including dendritic cells, T cells, and tumor cells, are being modified with a variety of genes, including those encoding antigens, cytokines, and chemokines, in order to enhance tumor immunity.

Antitumor immune response by CX3CL1 fractalkine gene transfer depends on both NK and T?cells

The CX3C chemokine fractalkine (CX3CL1) exists as both a membrane-bound form promoting firm cell-cell adhesion and a soluble form chemoattracting leukocytes expressing its receptor CX3CR1. When adenoviral vector expressing mouse fractalkine (AdFKN) was transduced to the tumor cells, fractalkine was expressed as both membrane-bound form on the tumor cells and soluble form in the supernatant in vitro. Intratumoral injection of AdFKN (1 x 10(9)PFU/tumor) into C26 and B16F10 tumors resulted in marked reduction of tumor growth compared to control (C26: 86.5%, p<0.001; B16F10: 85.5%, p<0.001). Histological examination of tumor tissues revealed abundant infiltration of NK cells, dendritic cells, and CD8(+) T lymphocytes 3 and/or 6 days after treatment with AdFKN. Splenocytes from mice treated by AdFKN developed tumor-specific cytotoxic T cells, and thereby protected from rechallenging with parental tumor cells. Antitumor effects by AdFKN were completely abrogated in both NK cell-depleted mice and CD8(-/-) mice, and partially blocked in CD4(-/-) mice. These data indicated that fractalkine mediates antitumor effects by both NK cell-dependent and T cell-dependent mechanisms. This study suggests that fractalkine can be a suitable candidate for immunogene therapy of cancer because fractalkine induces both innate and adaptive immunity.

Anti-tumor activity of chemokine is affected by both kinds of tumors and the activation state of the host’s immune system: implications for chemokine-based cancer immunotherapy

In this study, we screened the anti-tumor activity of murine chemokines including CCL17, CCL19, CCL20, CCL21, CCL22, CCL27, XCL1, and CX3CL1 by inoculating murine B16BL6, CT26, or OV-HM tumor cells, all of which were transfected with chemokine-expressing fiber-mutant adenovirus vector, into immunocompetent mice. A tumor-suppressive effect was observed in mice inoculated with CCL19/B16BL6 and XCL1/B16BL6, and CCL22/OV-HM showed considerable retardation in tumor growth. In the cured mice inoculated with CCL22/OV-HM, a long-term specific immune protection against parental tumor was developed. However, we were unable to identify the chemokine that had a suppressive activity common to all three tumor models. Furthermore, an experiment using chemokine-transfected B16BL6 cells was also performed on mice sensitized with melanoma-associated antigen. A drastic enhancement of the frequency of complete rejection was observed in mice inoculated with CCL17-, CCL19-, CCL22-, and CCL27-transfected B16BL6. Altogether, our results suggest that the tumor-suppressive activity of chemokine-gene immunotherapy is greatly influenced by the kind of tumor and the activation state of the host's immune system.

Intralesional Injection of Adenovirus Encoding CC Chemokine Ligand 16 Inhibits Mammary Tumor Growth and Prevents Metastatic-Induced Death after Surgical Removal of the Treated Primary Tumor

The CC chemokine ligand (CCL)16 exerts chemotactic activity on human monocytes and lymphocytes. Although no murine homologous has been defined, the TSA mouse adenocarcinoma cells engineered to express human CCL16 are rapidly rejected by syngenic mice. An adenovirus encoding CCL16 (AdCCL16) was generated using a Cre-Lox-based system and was used to determine whether this chemokine might also block pre-existing tumors. Both recombinant and viral CCL16 showed in vitro chemotactic activity for murine CD4(+) and CD8(+) lymphocytes and dendritic cells (DC). AdCCL16, but not the control empty vector, when injected in established nodules significantly delayed tumor growth. Immunohistochemistry revealed accumulation of CD4(+) and CD8(+) T cells and DC in the treated tumors as well as in draining lymph nodes. DC from such lymph nodes stimulated IFN-gamma by a T cell clone specific for the known TSA tumor-associated Ag (TAA), suggesting the tumor origin of these cells. Lymphocytes from the same nodes showed specific CTL activity against TSA tumor cells and their immunodominant TAA peptide. Antitumor activity required CD4, CD8, and IFN-gamma production, as shown using subset-depleted and knockout mice. Despite the robust and rapid immune response triggered by intratumoral injection of AdCCL16, the lesions were not completely rejected; however, the same treatment given before surgical excision of primary lesions prevented metastatic spread and cured 63% of mice bearing the 4T1 mammary adenocarcinoma, which is perhaps the most compelling model of spontaneous metastasis.

Chemoattraction, adhesion and activation of natural killer cells are involved in the antitumor immune response induced by fractalkine/CX3CL1

Fractalkine (FK, also called neurotactin or CX3CL1) is a CX3C chemokine that can chemoattract T lymphocytes, monocytes, dendritic cells (DC) and natural killer (NK) cells. One of our previous studies demonstrated that FK in soluble form can chemoattract T cells and DC and membrane-bound FK can adhere T cells and DC. Vaccination with 3LL lung carcinoma cells gene-modified with FK (3LL-FK) induces potent antitumor CTL response. The aim of the present study is to investigate whether NK cells participate in FK-induced antitumor immunity. We found that NK activity was increased in mice inoculated with 3LL-FK and in vivo depletion of NK cells resulted in the decreased tumor growth inhibition of 3LL-FK, indicating that NK cells play an important role in the antitumor immunity induced by FK. Further studies showed 3LL-FK could chemoattract, adhere NK cells and attract more NK cells to infiltrate into tumor tissue. Incubation of NK cells with 3LL-FK could increase the cytotoxicity of NK cells against YAC-1 cells and even against NK-resistant parental 3LL cells. IL-12 production increased more significantly in the 3LL-FK tumor nodules. Taken together with CTL response induced by 3LL-FK, our data demonstrate that FK, expressed by gene-modified tumor cells, can induce potent antitumor effect through different mechanisms, one of which involves chemoattraction of NK cells into tumor sites and activation of NK cells.

Cyclosporin A impairs dendritic cell migration by regulating chemokine receptor expression and inhibiting cyclooxygenase-2 expression

Migration of dendritic cells (DCs) into tissues and secondary lymphoid organs plays a crucial role in the initiation of innate and adaptive immunity. In this article, we show that cyclosporin A (CsA) impairs the migration of DCs both in vitro and in vivo. Exposure of DCs to clinical concentrations of CsA neither induces apoptosis nor alters development but does impair cytokine secretion, chemokine receptor expression, and migration. In vitro, CsA impairs the migration of mouse bone marrow-derived DCs toward macrophage inflammatory protein-3beta (MIP-3beta) and induces them to retain responsiveness to MIP-1alpha after lipopolysaccharide (LPS)-stimulated DC maturation, while in vivo administration of CsA inhibits the migration of DCs out of skin and into the secondary lymphoid organs. CsA impairs chemokine receptor and cyclooxygenase-2 (COX-2) expression normally triggered in LPS-stimulated DCs; administration of exogenous prostaglandin E2 (PGE2) reverses the effects of CsA on chemokine receptor expression and DC migration. Inhibition of nuclear factor-kappaB (NF-kappaB) and mitogen-activated protein kinase (MAPK) pathway signaling by CsA may be responsible for the CsA-mediated effects on the regulation of chemokine receptor and cyclooxygenase-2 (COX-2) expression. Impairment of DC migration due to inhibition of PGE2 production and regulation of chemokine receptor expression may contribute, in part, to CsA-mediated immunosuppression.

Tumor and CD4 T-cell interactions: tumor escape as result of reciprocal inactivation

This paper addresses the capacity of naive, effector, and memory CD4 T cells to control growth of a major histocompatibility complex (MHC) class II-positive B-cell lymphoma in vivo. To assess the role of T cells on their own without contributions by B cells, antibodies, or natural killer (NK) cells, we generated pure effector or memory CD4 T cells in Rag-/-gc-/- mice deficient in endogenous lymphocytes and NK cells. Lymphoma cells expressing a model antigen were injected into mice with T cells of cognate specificity that were either naive or in effector or resting memory state. Naive T cells were unable to prevent tumor growth, probably due to delay of efficient cross-presentation by dendritic cells. However, both effector and memory T cells, dependent on the amount of antigen available, controlled the tumor for a considerable period of time without the need for dendritic cell stimulation. Nevertheless, the tumor eventually grew uncontrolled in all cases. This was not because of a defect in T-cell homing to the tumor site or loss of MHC class II or costimulatory molecules by the tumor, but reflected mutual paralysis of T-cell responsiveness and antigen processing by tumor cells.

Intratumoral expression of macrophage-derived chemokine induces CD4+ T cell-independent antitumor immunity in mice

Macrophage-derived chemokine is chemotactic for a variety of leukocytes, and has been shown to be involved in T 2-mediated cellular immunity. To evaluate the role of this chemokine in tumor immunity in vivo, an adenovirus vector encoding the human macrophage-derived chemokine cDNA (AdMDC) was administered to established murine tumors. Gene transfer with AdMDC significantly inhibited tumor growth and prolonged animal survival. AdMDC was not directly cytotoxic to tumor cells, but splenocytes from animals that received intratumoral AdMDC were able to lyse syngeneic tumor cells, and purified splenic CD8 cells secreted interferon-gamma in a tumor-specific manner. The antitumor activity of AdMDC was lost in mice lacking CD8 T lymphocytes, but surprisingly, it was preserved in animals lacking CD4 cells, as was the systemic cytotoxic T lymphocyte response. Systemic NK cells did not play a role in the antitumor immune response induced by AdMDC. Experiments using knockout mice demonstrated that host expression of MHC Class I, but not Class II, IL-4, or IL-12, was necessary for AdMDC to exert its antitumor effect, and immunohistochemistry demonstrated infiltrates of CD8 and CD86 cells, but not CD4 cells in treated tumors. These studies highlight a new function for macrophage-derived chemokine by demonstrating that it possesses in vivo antitumor activity with CD8 T cells as the effector cells, and interestingly, that the CD4 cell/MHC II pathway of CD8 cell activation is not required for the antitumor effects of this chemokine.(H)

Fractalkine transgene induces T-cell-dependent antitumor immunity through chemoattraction and activation of dendritic cells

Fractalkine (FK, also called neurotactin or CX3CL1) is a CX3C chemokine that can chemoattract T lymphocytes, monocytes and NK cells. In our study, we investigated the induction of antitumor response by FK gene transfer. FK gene-modified 3LL lung carcinoma cells (3LL-FK) could both secrete soluble form and express membrane-bound form of FK. The tumor growth of 3LL-FK was decreased. Vaccination with 3LL-FK was effective in the induction of protective immunity and CTL. In vivo depletion analysis demonstrated that CD8(+) T cells are the main participating cells of the antitumor response. Obvious infiltrations of CD8(+) T cells, CD4(+) T cells and dendritic cells (DC) were observed in the tumor sites, suggesting that 3LL-FK might induce antitumor immunity through chemoattraction and activation of T cells and DC. Then we investigated the chemoattraction and activation of DC by 3LL-FK. Chemotaxis assay showed that the supernatants of 3LL-FK could chemoattract immature DC, which were found to express FK receptor CX3CR1, and the immature DC could obviously adhere to 3LL-FK. Adherence of DC to 3LL-FK resulted in phenotypic maturation and upregulated IL-12 secretion of DC, and more strong stimulation of allogeneic T-cell proliferation by DC. The increased production of IL-2 and IFNgamma in 3LL-FK tumor tissue was also observed. Our data suggested that FK gene transfer to tumor cells could induce T-cell-dependent antitumor immunity through chemoattraction and activation of DC.