HIGH EXPRESSION OF CHEMOKINE GENE AS A FAVORABLE PROGNOSTIC FACTOR IN RENAL CELL CARCINOMA

CCL5 as an adjuvant for cancer immunotherapy

IMPORTANCE OF THE FIELD

To date cancer immunotherapy has only achieved limited clinical efficacy, thus more efficient immunotherapeutic approaches need to be explored. The CC chemokine CCL5 plays a role in chemoattraction and activation of immune cells implying its potential clinical application as an adjuvant for boosting anti-tumor immunity, although an effect on carcinogenesis and tumor cell invasiveness is also reported to be associated with CCL5.

AREAS COVERED IN THIS REVIEW

Recent progress in exploiting CCL5 as an adjuvant for cancer prevention and treatment, and updated understanding on how CCL5 is involved in tumor invasiveness and carcinogenesis.

WHAT THE READER WILL GAIN

CCL5 represents a natural adjuvant for enhancing anti-tumor immune responses. However, animal experiments and clinical reports suggest that CCL5 plays a role in carcinogenesis and invasiveness of tumor cells. Therefore, a CCL5-based cancer therapeutic approach needs to avoid the CCL5-associated potential detrimental effects.

TAKE HOME MESSAGE

CCL5 has a pre-eminent role in chemotaxis and activation of a wide spectrum of immune cells. CCL5 functions as an adjuvant to boost anti-tumor immunity by diverse protocols such as co-immunization of recombinant CCL5 protein with tumor-associated antigen, vaccination with CCL-5-expressing tumor cells, or viral vector delivery of CCL5 cDNA into growing tumor. CCL5 may also promote tumor cell survival, proliferation and invasion by different mechanisms.

Immunologic mechanisms in RCC and allogeneic renal transplant rejection

The tolerance state that exists between renal cell carcinoma (RCC) and the host's immune system would be an ideal situation in the setting of human kidney transplantation, in which graft tolerance is the ultimate goal of immunosuppressive therapy. On the other hand, acute rejection, as it appears in renal allografts, would be the optimal immunologic situation in patients with RCC. Analysis of the underlying mechanisms of acute allograft rejection and local pro-tumor immunosuppression could help to identify potential therapeutic targets for inducing immune tolerance in allograft recipients and immune rejection in RCC patients. Experimental kidney transplantation might be a suitable model in which to analyze these processes. Macrophages are a prominent and vital cell type in the cellular infiltrate seen in both RCC and renal allografts. Depending on their polarization, they can initiate and promote either proinflammatory or pro-tumor responses, which lead to tissue rejection or acceptance, respectively. Improved understanding of macrophage biology could lead to therapeutic modification of their function in order to promote a desirable immunologic response in either RCC or transplant tissue.

Decreased expression of miR-125b and miR-100 in oral cancer cells contributes to malignancy

Altered microRNA (miRNA) expression profiles have been observed in numerous malignancies, including oral squamous cell carcinoma (OSCC). However, their role in disease is not entirely clear. Several genetic aberrations are characteristic of OSCC, with amplification of chromosomal band 11q13 and loss of distal 11q being among the most prevalent. It is not known if the expression levels of miRNAs in these regions are altered or whether they play a role in disease. We hypothesize that the expression of miRNAs mapping to 11q are altered in OSCC because of loss or amplification of chromosomal material, and that this contributes to the development and progression of OSCC. We found that miR-125b and miR-100 are down-regulated in OSCC tumor and cell lines, and that transfecting cells with exogenous miR-125b and miR-100 significantly reduced cell proliferation and modified the expression of target and nontarget genes, including some that are overexpressed in radioresistant OSCC cells. In conclusion, the down-regulation of miR-125b and miR-100 in OSCC appears to play an important role in the development and/or progression of disease and may contribute to the loss of sensitivity to ionizing radiation.

Role of the chemokines CCL3/MIP-1 alpha and CCL5/RANTES in sponge-induced inflammatory angiogenesis in mice

OBJECTIVE

We examined the potential contribution of CCL3 and CCL5 to inflammatory angiogenesis in mice.

METHODS

Polyester-polyurethane sponges were implanted in mice and blood vessel counting and hemoglobin, myeloperoxidase and N-acetylglucosaminidase measurements used as indexes for vascularization, neutrophil and macrophage accumulation, respectively.

RESULTS

CCL3 and CCL5 were expressed throughout the observation period. Exogenous CCL3 enhanced angiogenesis in WT, but angiogenesis proceeded normally in CCL3(-/-) mice, suggesting that endogenous CCL3 is not critical for sponge-induced angiogenesis in mice. CCL5 expression was detected at day 1, but levels significantly increased thereafter. Exogenous CCL5 reduced angiogenesis in WT mice possible via CCR5 as CCL5 was without an effect in CCR5(-/-) mice. Treatment of WT with the CCR1/CCR5 antagonist, Met-RANTES, prevented neutrophil and macrophage accumulation, but enhanced sponge vascularization.

CONCLUSION

Thus, endogenous CCL3 appears not to play a role in driving sponge-induced inflammatory angiogenesis in mice. The effects of CCL5 were anti-angiogenic and appeared to be mediated via activation of CCR5.

Chemokine receptors expression and migration potential of tumor-infiltrating and peripheral-expanded Vgamma9Vdelta2 T cells from renal cell carcinoma patients

We previously showed that Vdelta2 T cells infiltrate renal tumors and can be expanded as potent cytotoxic effectors from peripheral blood mononuclear cells of most renal cell carcinoma (RCC) patients, using a structural analog of nonconventional T-cell receptor gamma9delta2 ligand, bromohydrin pyrophosphate, and interleukin-2 (IL-2). In this study, we have further investigated the differentiation status and the migration potential of circulating and tumor-infiltrating Vgamma9Vdelta2 T lymphocytes from RCC patients. The repertoire of tumor-infiltrating and peripheral Vgamma9Vdelta2 T cells from RCC patients was characterized by a dominant CD27- CD45RA- subset. These effector memory Vgamma9Vdelta2 T cells were efficiently expanded using bromohydrin pyrophosphate combined with IL-15, but not IL-2. In addition, peripheral Vgamma9Vdelta2 T cells from RCC patients present a modified chemotactic pattern compared with donors. After ex vivo activation, peripheral expanded Vgamma9Vdelta2 T cells acquire low-migration capacities toward renal cells. Tumor-infiltrating Vgamma9Vdelta2 T cells migrated with higher efficiency toward primary renal tumor cells. The traffic toward tumor cells required the CXCL12/CXCR4 interaction. Altogether, these results outline that those Vgamma9Vdelta2 effectors exhibit differential migration capacities according to their localization, their differentiation status, and the tumor microenvironment parameters that may influence their use in immunotherapy.

A three-gene expression signature model to predict clinical outcome of clear cell renal carcinoma

Renal cell carcinomas (RCCs) are morphologically and genetically heterogeneous tumors and present diverse clinical courses. We developed a scoring system using levels of gene expression to predict the outcome for clear cell RCC patients. We selected differentially expressed genes from the DNA microarray data of 27 clear cell RCCs; 16 were metastasis phenotypes and 11 were not. We compared the selected gene set with previously published data and identified 33 overlapping genes closely associated with patient outcome. We selected the 12 top-ranked genes and confirmed the level of expression using quantitative reverse transcriptase PCR. Multivariate Cox analysis revealed that 3 genes-vascular cell adhesion molecule 1 (VCAM1), endothelin receptor type B (EDNRB), and regulator of G-protein signaling 5 (RGS5)-were the most tightly associated with cancer-specific survival and that higher expression of the 3 genes correlated with better outcome. A formula for an outcome predictor was generated from integration of the measurements of the expression levels of the 3 genes. Multivariate Cox models combined with a split-sample cross-validation method in a cohort of 386 clear cell RCC patients demonstrated that the derived score for outcome prediction was an independent predictor in cancer-specific survival tests. The accuracy of the prediction of cancer death after nephrectomy was improved by the inclusion of this score in receiver operating characteristic analysis from multivariate logistic regression models, suggesting that a scoring system based on the expression levels of these 3 genes is useful in the prediction of survival for patients with clear cell RCC.

RANTES-403 polymorphism is associated with reduced risk of gastric cancer in women

BACKGROUND

Men are more susceptible to gastric cancer (GC) than women. However, the genetic factors associated with the sex difference are not well understood. Chemokines have been shown to modulate tumor behavior, and the sex-specific effect of the chemokine polymorphisms on the host susceptibility to several diseases has been reported. We aimed to determine the role of chemokine polymorphisms on host susceptibility to GC, with special interest on their sex-specific effect.

METHODS

A hospital-based case-control study, including 177 patients with GC and 217 age-matched unaffected healthy controls, was performed in three major tertiary care hospitals. Genotyping for regulated upon activation, normal T-cell expressed and secreted (RANTES) -403 A/G and -28 C/G, CC chemokine receptor 5 (CCR5) deletion, and CCR2-V64I was performed using peripheral blood DNA.

RESULTS

The RANTES -403 GA and AA genotypes were independently associated with a 2.3-fold reduced risk of developing GC (OR=0.44, 95% CI 0.22-0.90, P=0.025) compared with GG genotype in women, but not in men. The RANTES -28C/G and CCR2-V64I polymorphisms were not associated with different risk of developing GC. The tumor stage, histological features, and survival rate were not different when stratified by RANTES -403 and -28 and CCR2-V64I genotypes.

CONCLUSIONS

Our data indicate that women who inherit A allele at RANTES -403 may be at reduced risk of GC.

Chemokines in tumor angiogenesis and metastasis

Chemokines are a large group of low molecular weight cytokines that are known to selectively attract and activate different cell types. Although the primary function of chemokines is well recognized as leukocyte attractants, recent evidences indicate that they also play a role in number of tumor-related processes, such as growth, angiogenesis and metastasis. Chemokines activate cells through cell surface seven trans-membranes, G-protein-coupled receptors (GPCR). The role played by chemokines and their receptors in tumor pathophysiology is complex as some chemokines favor tumor growth and metastasis, while others may enhance anti-tumor immunity. These diverse functions of chemokines establish them as key mediators between the tumor cells and their microenvironment and play critical role in tumor progression and metastasis. In this review, we present some of the recent advances in chemokine research with special emphasis on its role in tumor angiogenesis and metastasis.

Immune-mediated modulation of breast cancer growth and metastasis by the chemokine Mig (CXCL9) in a murine model

Current immunotherapies are limited by several factors, including the failure to recruit sufficient numbers of immune effector cells to tumors. The chemokine monokine induced by gamma-interferon (Mig; CXCL9) attracts activated T cells and natural killer (NK) cells bearing the chemokine receptor CXCR3. We investigated Mig as an immunotherapeutic agent in a syngeneic murine model of metastatic breast cancer. We transfected the highly malignant murine mammary tumor cell line 66.1 to stably express murine Mig cDNA. Immune-competent mice injected with Mig-expressing tumor cells developed smaller local tumors and fewer lung metastases, and they survived longer than mice injected with vector-control tumor cells. Mig-mediated inhibition of local tumor growth was lost in the absence of host T cells. Mig-transduced tumors had increased numbers of CD4 T cells compared with vector-control tumors, consistent with the T-cell chemoattractant property of Mig, and many tumor-infiltrating host cells expressed CXCR3. NK cells had not been examined previously as a possible effector cell in Mig-based therapies. Our studies now show that NK cells are critical to the mechanism by which Mig limits metastasis. Inhibition of angiogenesis was not implicated as a mechanism of Mig-mediated therapy in this model. These studies support the hypothesis that by manipulating the Mig-CXCR3 gradient, it is possible to direct host immune effector cells to tumors, curtailing both local tumor growth and metastasis. These studies also implicate host NK cells as an additional effector cell critical for Mig-mediated control of metastasis.

Mechanisms of disease: regulation of RANTES (CCL5) in renal disease

Chemokines (chemoattractant cytokines) are fundamental regulators of immune cell movement from the bloodstream into tissues. Regulating expression of chemokines might, therefore, alleviate inflammation in autoimmune diseases and transplant rejection, or augment immune responses in cancer and immunodeficiency. RANTES (regulated upon activation, normal T cell expressed and secreted [also known as CCL5]) is a model chemokine of relevance to a myriad of diseases. Regulation of RANTES expression is complex. In fibroblasts and monocytes, rel proteins alone suffice to induce transcription of RANTES. By contrast, expression of RANTES in T lymphocytes 3-5 days after activation requires the development of a molecular complex (enhancesome) including KLF13 (Krueppel-like factor 13), rel proteins p50 and p65, and scaffolding proteins. This complex recruits enzymes involved in acetylation, methylation and phosphorylation of chromatin, and ultimately in the expression of RANTES. In addition, KLF13-the lynchpin for recruitment of this molecular complex-is itself translationally regulated. Such complex regulation of biological systems has major implications for the rational design of drugs aimed at increasing or decreasing inflammatory responses in patients.

CXC Chemokine Ligand 9/Monokine Induced by IFN-γ Production by Tumor Cells Is Critical for T Cell-Mediated Suppression of Cutaneous Tumors

The role of tumor-produced chemokines in the growth of malignancies remains poorly understood. We retrieved an in vivo growing MCA205 fibrosarcoma and isolated tumor cell clones that produce both CXCL9/monokine induced by IFN-gamma (Mig) and CXCL10/IFN-gamma-inducible protein 10 following stimulation with IFN-gamma and clones that produce IFN-gamma-inducible protein 10 but not Mig. The Mig-deficient variants grew more aggressively as cutaneous tumors in wild-type mice than the Mig-producing tumor cells. The growth of Mig-expressing, but not Mig-deficient, tumor cells was suppressed by NK and T cell activity. Transduction of Mig-negative variants to generate constitutive tumor cell production of Mig resulted in T cell-dependent rejection of the tumors and in induction of protective tumor-specific CD8(+) T cell responses to Mig-deficient tumors. The results indicate a critical role for tumor-derived Mig in T cell-mediated responses to cutaneous fibrosarcomas and suggest the loss of Mig expression as a mechanism used by tumor cells to evade these responses.

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.

Bmi-1 cooperates with human papillomavirus type 16 E6 to immortalize normal human oral keratinocytes

Bmi-1 is a member of the polycomb group (PcG) transcription repressors and is implicated in human carcinogenesis. In normal human oral keratinocytes (NHOK), we found that exogenous Bmi-1 expression significantly extended the replicative life span without causing cellular immortalization. Immortalization of NHOK occurs only in combination with human papillomavirus type 16 E6 (HPV-16 E6) but not with E7. During immortalization of NHOK by sequential expression of exogenous Bmi-1 and E6, telomerase activation was observed only after the cells had overcome crisis. Genetic analysis with E6 deletion mutants revealed that the intact second zinc finger domain (amino acids 118-122) was necessary for its cooperative effects with Bmi-1 in the immortalization process. Using these mutants, we found that the increased telomerase activity was closely associated with cell immortalization by Bmi-1 and E6, whereas p53 degradation was not. Using microarray analysis, we identified genes that are immortalization-specific and may participate in the process of NHOK immortalization by Bmi-1 and HPV-16 E6. Our results provide new information on the roles of Bmi-1 and HPV-16 E6 in the multi-step process of oral epithelial carcinogenesis.

Analysis of the expression of HLA class I, proinflammatory cytokines and chemokines in primary tumors from patients with localized and metastatic renal cell carcinoma

Changes in the human leukocyte antigen (HLA) class I expression and cytokine and chemokine production both by cancer cells and by normal surrounding tissue are believed to be responsible for immune escape and tumor progression. In this study, we compared the tumor expression levels of HLA heavy chain (HLAhc), beta-2-microglobulin (beta2m), chemokines (Interferon-gamma-inducible Protein-10 (IP-10), Interferon-inducible T-cell Alpha-Chemoattractant (I-TAC), Stromal cell-Derived Factor-1 (SDF-1), Macrophage Inflammatory Protein-1-alpha (MIP-1-alpha) and Regulated upon Activation, Normally T-Expressed, and presumably Secreted (RANTES)) and cytokines (Vascular Endothelial Growth Factor (VEGF), Interferon-gamma (IFN-gamma), Interleukin-10 (IL-10), Tumor Growth Factor-beta (TGB-beta)) in primary tumors and adjacent normal tissues from patients with localized and metastatic renal cell carcinoma (RCC) using a quantitative real-time polymerase chain reaction technique. We report that the expression of HLAhc, beta2m and the studied cytokines and chemokines (except for SDF-1) was significantly higher in the tumor (29 samples) than in the normal tissue (14 samples). When we compared the tumor expression levels between patients with localized RCC and patients with advanced metastatic stage, we found that the messenger RNA expression levels of HLAhc and beta2m were much lower in patients with metastatic RCC (6 cases) than in patients with localized cancer (23 cases), with levels similar to those in normal tissue. This was also confirmed on a protein level by immunohistological labeling of tumor tissues. Thirty-nine percent of the analyzed RCC tumors showed partial loss of HLA class I molecules, while 6% of the tumors showed HLA class I total loss. The expression of IP-10, SDF-1 and VEGF-c was also significantly lower in patients with advanced tumor, while the IFN-gamma expression in metastatic RCC was not detectable. Our findings show that primary RCC tumors are characterized by a high expression of HLAhc and a presence of proinflammatory mediators and chemokines. We also observed that disease progression and development of metastasis in RCC are associated with decreased expression of HLAhc, beta2m, IP-10, SDF-1 and IFN-gamma. This microenvironment may suppress the cytotoxic response, creating conditions that favor tumor escape and cancer progression.

The chemokine network: a target in cancer biology?

Chemokine gradients are central to the movement of cells in both homeostatic and pathological processes. Most cancers express a complex array of chemokines that influence the local microenvironment through recruitment of stromal cells and by stimulating angiogenesis. Recently, the discovery of chemokine receptors on tumor cells has led to speculation that the chemokine system may be involved in cancer cell growth and survival, and possibly the development of site-specific spread. Understanding the networks of chemokines and their receptors in cancer will enable manipulation of this system. Both chemokines and their receptors represent targets for therapeutic intervention either with antibodies or small molecule antagonists. However, due to the complexity of the system, and the number of chemokines and receptors that are also expressed by normal cells, issues remain concerning whether systemic or local drug delivery are preferable and whether the redundancy of the system will compensate if one chemokine or receptor is targeted. Nevertheless, efficacy has been demonstrated in a number of experimental models. By targeting this network, it may be possible to generate anti-tumor immune responses by altering the chemokine and/or leukocyte balance in tumors; alternatively, chemokine/chemokine receptor-expressing cancer cells could be directly targeted.

Favorable prognosis of renal cell carcinoma with increased expression of chemokines associated with a Th1-type immune response

The potential role of chemokines in clinical tumors remains poorly understood. Recent investigations have shown the differential expression of chemokine receptors on lymphocytes mediating Th1- and Th2-type immune responses. We examined Th1- and Th2-associated cytokines and chemokines, as well as the expression of their receptors in tumor-infiltrating lymphocytes in renal cell carcinoma (RCC). Sixty-seven patients with sporadic RCC were analyzed for the expression of Th1- and Th2-associated genes using real-time polymerase chain reaction. Tumor infiltration by CXC chemokine receptor 3 (CXCR3)-positive and CC chemokine receptor 5 (CCR5)-positive cells was detected by immunohistochemistry and by flow cytometry. The expression of Th1-associated genes was significantly increased in tumors compared to normal kidney tissues. The expression of interferon-gamma correlated positively with that of Th1 chemokines. Tumors expressing higher Th1 chemokines did not recur after curative surgery. Multivariate analysis showed that increased monokine induced by interferon (IFN)-gamma (MIG) expression was an independent favorable prognostic factor. Immunohistochemistry showed that the degree of CXCR3-positive cell infiltration significantly correlated with IFN-gamma inducible protein 10, MIG and IFN-gamma-inducible T cell a chemoattractant expression (I-TAC). Flow cytometric analysis showed increased expression of CXCR3 and CCR5 in tumor-infiltrating T lymphocytes compared to that in peripheral blood T cells. These results suggest that upregulation of the Th1-type immune response in RCC tumors with a favorable prognosis may be mediated by Th1-associated chemokines. Integrity of the Th1-type immune response seems to be required for tumor regression, suggesting that detection and correction of a defect in the Th1-type response cascade would thus be one of the main targets for tailor-made immunotherapy and gene therapy in RCC.

Current status and perspective of antiangiogenic therapy for cancer: urinary cancer

Angiogenesis is considered a prerequisite for solid tumor growth. Antiangiogenic therapy reduces tumor size and extends host survival in a number of preclinical animal models. However, in humans antiangiogenic therapy is a poor promoter of tumor regression and has shown minimal effect on patient survival. In urinary cancers, such as renal cell cancer, prostate cancer, and bladder cancer, advanced refractory disease is a good candidate for antiangiogenic therapy because of its resistance to ordinary chemotherapy, radiotherapy, and hormonal therapy. Unique characteristics of molecular mechanisms underlie the induction of angiogenesis in urinary cancers. In this review, we summarize these unique mechanisms and review the results of clinical trials of antiangiogenic therapy for these cancers, discussing prospects and problems relating to antiangiogenic therapy.

Expression of CCL5 (RANTES) and CCR5 in prostate cancer

BACKGROUND

Expression of the inflammatory chemokine CCL5 (RANTES) by tumor cells is thought to correlate with the progression of several cancers. CCL5 was shown to induce breast cancer cell migration, mediated by the receptor CCR5. A CCR5 antagonist was demonstrated to inhibit experimental breast tumor growth. Recently, CCL5 and CCR5 mRNA expression was reported in prostate cancer (PCa) tissues. Herein, we characterized CCL5 and CCR5 expression in cultures of PCa cells and explored possible functions of CCL5 in PCa progression.

METHODS

Quantitative RT-PCR, ELISA, and immunohistochemical staining were performed to examine CCL5 expression in prostate cell lines. CCR5 expression was measured by flow cytometry. Proliferation and invasion assays were performed to determine potential functions of CCL5 and CCR5 in PCa.

RESULTS

Expression of CCL5 mRNA and protein was found in human PCa cell lines (PC-3; DU-145; LNCaP) and primary prostate adenocarcinoma cells. CCL5 and CCR5 were also detected in human PCa tissues. CCR5 expression was demonstrated on the cell surface of PCa cells, as well as in intracellular pools. Incubation with CCL5 (10-100 ng/ml) induced PCa cell proliferation, and the CCR5 antagonist TAK-779 inhibited CCL5-induced proliferation. CCL5 was found to stimulate PCa cell invasion, and TAK-779 blocked the effects of CCL5.

CONCLUSIONS

In light of evidence that inflammation influences the pathogenesis of PCa, these results suggest that inflammatory chemokines, such as CCL5, expressed by prostate cells may act directly on the growth and survival of PCa cells. Chemokine receptor antagonists may thus block autocrine mechanisms of PCa progression.

Analysis of NK cells and chemokine receptors in tumor infiltrating CD4 T lymphocytes in human renal carcinomas

Recent data suggest that chemokines and chemokine receptors mediate leukocyte recruitment of all components of the antitumor response. This study aimed to phenotypically characterize the immune lymphocyte infiltrate in human renal cell carcinomas RCCs and at the invasive margin (tumor-host interface) and to define the association of these findings with established prognostic indicators. Tumor infiltrating lymphocytes TILs were obtained from 24 patients with RCC undergoing radical nephrectomy. Peripheral blood cells from 37 patients were also obtained before surgery. Our findings are consistent with the preferential recruitment of CD4+ Th1-polarized effector memory cells that express CXCR3/CCR5. These cells were the main component of TILs and expressed as CXCR3, CCR5, CD45RO, and CD95. Natural killer (NK) cells were found in significantly higher proportions in TILs of RCCs than in peripheral blood lymphocytes (PBLs) or in other tumors studied (colorectal and breast cancers), where these cells were found in small proportions. No differences in nuclear grade or other studied parameters were observed between the TILs and the lymphocytes present at the invasive margin, which showed a similar composition. However, differences were found according to the tumor stage. First, significantly fewer NK cells were observed in PBLs from metastatic patients. Second, a significantly lower proportion of CCR5/CXCR3/CD4+ cells and a higher proportion of CCR4/CD4+ cells were observed in metastatic patients, suggesting that preferential Th1-polarization may gradually change during the progression of renal cancer cells. Finally, the frequency of CD25/CD4+ cells was higher in metastatic patients. Although the sample of patients with metastasis was small, the overall results suggest a change in composition of the TILs that may potentially confer a selective advantage for tumor growth and may account for the suppression of an effective cytotoxic response.

Up-regulation of functional chemokine receptor CCR3 in human renal cell carcinoma

There is increasing evidence that chemokines and chemokine receptors are causally involved in tumorigenesis by facilitating tumor proliferation and metastasis. Little is known about the possible function of chemokine receptors in the development and progression of renal cell carcinoma (RCC). We, therefore, analyzed the expression of chemokine receptors in tumor specimens and adjacent healthy kidney tissues [normal kidney cell (NKC)] from 10 RCC patients. We also characterized the permanent RCC cell line A-498. CCR6, CXCR2, and CXCR3 were consistently expressed by both malignant cells and NKCs. A-498 displayed additional expression of CXCR4. Importantly, the expression of CCR3 was almost absent on NKCs but clearly enhanced in a substantial proportion of RCC specimens. The primary CCR3 ligand, eotaxin-1/CCL11, induced intracellular Ca2+ mobilization, receptor internalization, and proliferation in A-498 cells confirming signaling competence of RCC-associated CCR3. In addition, we screened tumor tissue sections of 219 patients and found that 28% (62 of 219) expressed the CCR3 receptor. The presence of CCR3 in tumor samples seemed to correlate with the grade of malignancy. Previous work has established that eotaxin-1 expression is induced by tumor necrosis factor-alpha, a cytokine known to be present in RCC tissue. Our data, therefore, supports a scenario in which eotaxin-1 as part of tumor-associated inflammation promotes progression and dissemination of CCR3-positive RCC.