Expression of cytokine mRNA transcripts in renal cell carcinoma

Sunitinib does not impair natural killer cell function in patients with renal cell carcinoma

Although the available treatment options have expanded, the survival of patients with metastatic renal cell carcinoma (RCC) remains poor. As patients with RCC lack responsiveness to chemotherapy or radiation, therapeutic options predominantly include surgical interventions and immunomodulatory approaches, including the administration of tyrosine kinase inhibitors (TKIs) such as sunitinib. Natural killer (NK) cells have been reported to be key players in TKI-mediated off-target effects on the immune system. However, only limited information is available regarding the possible impact of sunitinib on the function of NK cells of individual patients. The present study reports on the immunomonitoring results of three patients with metastatic RCC who underwent sunitinib treatment. These results were compared with age-matched, healthy controls in terms of the immune status of T, B and NK cells, focusing on functional in vitro analyses of NK cells. In all three patients, NK cell number, subset distribution and function, as measured by cluster of differentiation 107a degranulation, did not exhibit any significant alterations as a result of sunitinib treatment. These results indicate that sunitinib does not negatively affect NK cell function, which supports the pursuit of therapeutic modalities that combine immunomodulation and NK cell-stimulating approaches.

Interleukin-6, Interleukin-10 and Heat Shock Protein-90 Expression in Renal Epithelial Neoplasias and Surrounding Normal-Appearing Renal Parenchyma

Cytokines, notably the interleukins IL-6 and IL-10, have an important role in the development and progression of renal-cell carcinomas, acting in the host-tumor interaction and in tumor bulk. Heat shock proteins (HSP), in particular HSP-90, may have a regulatory role in cytokine biosynthesis and prognostic implication in some tumors. To define the roles of the cytokines IL-6 and IL-10 and HSP-90 in the progression of renal-cell carcinoma we analyzed immunohistochemical expression of these proteins in human renal-cell carcinomas from 95 total nephrectomies. IL-6, IL-10 and HSP-90 proteins were more strongly expressed in epithelium and stroma of the renal tumoral compartment than in adjacent normal peritumoral tissue. But the difference reached significance only for HSP-90 protein. The percentage of cells expressing IL-6, IL-10 and HSP-90 immunoreactivity was higher in benign epithelial tumors, than in normal peritumoral tissue, but lower than in renal-cell carcinomas. Whereas HSP-90 immunoreactivity seemed higher in more aggressive histological phenotypes (collecting-duct carcinoma) of renal-cell carcinomas, IL-10 protein levels were higher in more advanced TNM stage (pT3) tumors. Our observation suggests that IL-6 and IL-10 and HSP-90 may be useful markers associated with the development and progression of renal-cell carcinomas and have independent functional roles in this malignant condition.

Modification of the tumor microenvironment as a novel target of renal cell carcinoma therapeutics

To move forward with immunotherapy, it is important to understand how the tumor microenvironment generates systemic immunosuppression in patients with renal cell carcinoma (RCC) as well as in patients with other types of solid tumors. Even though antigen discovery in RCC has lagged behind melanoma, recent clinical trials have finally authenticated that RCC is susceptible to vaccine-based therapy. Furthermore, judicious coadministration of cytokines and chemotherapy can potentiate therapeutic responses to vaccine in RCC and prolong survival, as has already proved possible for melanoma. Although high-dose interleukin 2 immunotherapy has been superseded as first-line therapy for RCC by promiscuous receptor tyrosine kinase inhibitors (rTKIs) such as sunitinib, sunitinib itself is a potent immunoadjunct in animal tumor models. A reasonable therapeutic goal is to unite antiangiogenic strategies with immunotherapy as first-line therapy for RCC. This strategy is equally appropriate for testing in all solid tumors in which the microenvironment generates immunosuppression. A common element of RCC and pancreatic, colon, breast, and other solid tumors is large numbers of circulating myeloid-derived suppressor cells (MDSCs), and because MDSCs elicit regulatory T cells rather than vice versa, gaining control over MDSCs is an important initial step in any immunotherapy. Although rTKIs like sunitinib have a remarkable capacity to deplete MDSCs and restore normal T-cell function in peripheral body compartments such as the bloodstream and the spleen, such rTKIs are effective only against MDSCs, which are engaged in phospho-STAT3-dependent programming (pSTAT3+). Unfortunately, rTKI-resistant pSTAT3- MDSCs are especially apt to arise within the tumor microenvironment itself, necessitating strategies that do not rely exclusively on STAT3 disruption. The most utilitarian strategy to gain control of both pSTAT3+ and pSTAT3- MDSCs may be to exploit the natural differentiation pathway, which permits MDSCs to mature into tumoricidal macrophages (TM1) via such stimuli as Toll-like receptor agonists, interferon γ, and CD40 ligation. Overall, this review highlights the mechanisms of immune suppression used by the different regulatory cell types operative in RCC as well as other tumors. It also describes the different therapeutic strategies to overcome the suppressive nature of the tumor microenvironment.

A meta-analysis of kidney microarray datasets: investigation of cytokine gene detection and correlation with rt-PCR and detection thresholds

Background

Microarrays provide a means to simultaneously examine the gene expression of the entire transcriptome in a single sample. Many studies have highlighted the need for novel software and statistical approaches to assess the measured gene expression. Less attention has been directed toward whether genes considered undetectable by microarray can be detected by other strategies or whether these genes can provide accurate gene expression determinations. In the kidney this is a concern for genes such as cytokines which dramatically influence the immune response but are often considered low abundance genes produced by a small number of cells.

Results

Using both publicly available and our own microarray datasets we analyzed the detection p-value and detection call values for 81 human kidney samples run on the U133A or U133Plus2.0 Affymetrix microarrays (Affymetrix, Santa Clara, CA). For the cytokine genes, the frequency of detection in each sample group (normal, transplant and renal cell carcinoma) was examined and revealed that a majority of cytokine related genes are not detectable in human kidney by microarray. Using a subset of 29 Mayo transplant samples, a group of seven transplant-related cytokines and eight non-cytokine genes were evaluated by real-time PCR (rt-PCR). For these 15 genes we compared the impact of decreasing microarray detection frequency with the changes in gene expression observed by both microarray and rt-PCR. We found that as microarray detection frequency decreased the correlation between microarray and rt-PCR data also decreased.

Conclusion

We conclude that, when analyzing microarray data from human kidney samples, genes generally expressed at low abundance (i.e. cytokines) should be evaluated with more sensitive approaches such as rt-PCR. In addition, our data suggest that the use of detection frequency cutoffs for inclusion or exclusion of microarray data may be appropriate when comparing microarray and rt-PCR gene expression data and p-value calculations.

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.

Cytokine gene polymorphisms as potential risk and protective factors in renal cell carcinoma

The major aim of this study was to investigate the association of the cytokine gene polymorphisms with the development of renal cell carcinoma (RCC). The study included 29 patients with RCC and 50 healthy controls. All genotyping (TNF-alpha, TGF-beta, IL-10, IL-6, IFN-gamma) experiments were performed using sequence-specific primers PCR (PCR-SSP). It was found that TNF-alpha -308 G/G and TGF-beta codon 10-25 T/T-G/C genotypes were significantly higher in frequency in the patients with RCC group compared with the healthy control group. Additionally, the frequency of TNF-alpha -308 G allele was significantly higher in the patients when compared to controls. On the other hand, the frequencies of TNF-alpha -308 G/A, IL-6 C/C and TGF-beta1 codon 10-25 C/C-G/G genotypes were significantly lower in the cancer group compared with the healthy control group. However, after correction for multiple comparisons (Bonferroni), these results did not remain significant. Nevertheless, these findings suggest that the TNF-alpha -308 G/G and TGF-beta codon 10-25 T/T-G/C genotypes may be potential risk factors for RCC, whereas TNF-alpha -308 G/A, IL-6 C/C and TGF-beta1 codon 10-25 C/C-G/G genotypes may be possible protective factors. The number of the cases has to be increased to investigate the independency of these polymorphisms involved in the oncogenesis of RCC.

Expression of transforming growth factor beta in renal cell carcinoma and matched non-involved renal tissue

TGFbeta1 is one of several cytokines produced by proximal tubular and renal cancer cells. Previous studies have been mainly focused on determining plasma or serum TGFbeta levels, its effect on RCC cultures, and the expression of TGFbeta mRNA. Cancerous and autologous normal kidney samples were obtained from 24 patients treated by radical nephrectomy. TGFbeta1 expression was determined using a semi quantitative Western blot analysis and immunohistochemistry. Blot densities and immunohistochemical expression intensities in normal and neoplastic tissue were compared, and subsequently correlated to tumor stage, histological type and nuclear grade. All tissue samples examined expressed TGFbeta1; mean tumor to non-involved kidney spot density ratio correlated with advancing stage and higher nuclear grade. The overexpression of TGFbeta1 in certain RCCs may partially explain their resistance to the growth suppression action of TGFbeta. The correlation with tumor stage and grade indicates a possible role in the development of metastatic potential as well as in host's immune response modulation.

Tachycardia-Induced Heart Failure Does Not Alter Myocardial P-glycoprotein Expression

STUDY OBJECTIVE

To determine the effects of tachycardia-induced heart failure on myocardial P-glycoprotein (P-gp) expression.

DESIGN

Nonblinded, parallel, sham-controlled, animal model study.

SETTING

University laboratory.

ANIMALS

Thirty mongrel dogs.

INTERVENTION

Heart failure was induced by rapid ventricular pacing over 4 weeks; sham procedures were performed for the control group.

MEASUREMENTS AND MAIN RESULTS

Myocardial biopsies were taken from the left ventricular lateral wall and prepared for P-gp quantification by laser-induced fluorescence. The relative amount of P-gp messenger RNA (mRNA) was assessed by reverse transcriptase polymerase chain reaction. Rapid ventricular pacing produced heart failure and reduced the area ejection fraction from 48% +/- 6% to 21% +/- 6% (p<0.05 vs baseline). However, heart failure did not alter the quantity of myocardial P-gp (0.20 +/- 0.02 microg/ml for the control group vs 0.23 +/- 0.02 microg/ml for the intervention group, p=0.4). Furthermore, heart failure did not alter P-gp expression significantly.

CONCLUSION

Myocardial P-gp does not change in response to tachycardia-induced heart failure. Thus, there is a low likelihood for P-gp-related drug resistance during a syndrome similar to tachycardia-induced heart failure.

Conventional (clear cell) renal carcinoma metastases have greater bcl-2 expression than high-risk primary tumors

Bcl-2 antagonizes p53-induced apoptosis and may contribute to chemoresistance. In renal cell carcinoma (RCC), the role of bcl-2 is not well-defined, though its expression is reportedly low in primary tumors and lacks prognostic value. This study evaluates patterns of bcl-2 expression in high-risk (pT(3)) primary tumors and in matched patient metastases. Immunohistochemical analysis of bcl-2 was performed on 149 cases of conventional (clear cell) RCC (112 pT(3) primaries, 37 metastases). Paraffin-embedded tissues were obtained from nephrectomies and metastatic resections. Median follow up was 48 months in the entire cohort and 69 months in living patients. We evaluated associations between bcl-2 expression and tumor recurrence or patient survival with the Cox regression test, and used the t-test and Pearson correlation methods to evaluate bcl-2 expression in primary and metastatic cases. Bcl-2 expression was observed at a higher frequency in metastases (21/37 cases; 57%) compared to primary tumors (24/112 cases; 21%; P < 0.001). The percentage of cells stained was greater in metastases than primary tumors (P = 0.003). This finding was also noted when expression in metastatic cases was compared with matched primaries (P = 0.05). Bcl-2 expression did not predict disease-free (P = 0.30), disease-specific (P = 0.90), or overall (P = 0.51) survival. Most RCC primary tumors have low-to-absent levels of bcl-2 protein, whereas most RCC metastases display greater protein levels. Bcl-2 expression in primary tumors does not predict clinical outcome. However, expression of bcl-2 protein occurs at a high frequency in RCC metastases when compared to primary tumors. It may be reasonable to target RCC patients displaying altered bcl-2 levels for molecular therapies, such as anti-bcl2, should metastatic disease develop.

Interleukin-1beta induces human proximal tubule cell injury, alpha-smooth muscle actin expression and fibronectin production

BACKGROUND

Tubulointerstitial lesions, characterized by tubular injury, interstitial fibrosis and the appearance of myofibroblasts, are the strongest predictors of the degree and progression of chronic renal failure. These lesions are typically preceded by macrophage infiltration of the tubulointerstitium, raising the possibility that these inflammatory cells promote progressive renal disease through fibrogenic actions on resident tubulointerstitial cells. The aim of the present study, therefore, was to investigate the potentially fibrogenic mechanisms of interleukin-1beta (IL-1beta), a macrophage-derived pro-inflammatory cytokine, on human proximal tubule cells (PTC).

METHODS

Confluent, quiescent, passage 2 PTC were established in primary culture from histologically normal segments of human renal cortex (N = 11) and then incubated in serum- and hormone-free media supplemented with either IL-1beta (0 to 4 ng/mL) or vehicle (control).

RESULTS

IL-1beta significantly enhanced fibronectin secretion by up to fourfold in a time- and concentration-dependent fashion. This was accompanied by significant (2.5- to 6-fold) increases in alpha-smooth muscle actin (alpha-SMA) expression, transforming growth factor beta (TGF-beta1) secretion, nitric oxide (NO) production, NO synthase 2 (NOS2) mRNA and lactate dehydrogenase (LDH) release. Cell proliferation was dose-dependently suppressed by IL-1beta. NG-methyl-l-arginine (L-NMMA; 1 mmol/L), a specific inhibitor of NOS, blocked NO production but did not alter basal or IL-1beta-stimulated fibronectin secretion. In contrast, a pan-specific TGF-beta neutralizing antibody significantly blocked the effects of IL-1beta on PTC fibronectin secretion (IL-1beta, 268.1 +/- 30.6 vs. IL-1beta+alphaTGF-beta 157.9 +/- 14.4%, of control values, P < 0.001) and DNA synthesis (IL-1beta 81.0 +/- 6.7% vs. IL-1beta+alphaTGF-beta 93.4 +/- 2.1%, of control values, P < 0.01).

CONCLUSION

IL-1beta acts on human PTC to suppress cell proliferation, enhance fibronectin production and promote alpha-smooth muscle actin expression. These actions appear to be mediated by a TGF-beta1 dependent mechanism and are independent of nitric oxide release.

Role of low nuclear grading of renal carcinoma cells in the functional profile of tumor-infiltrating T cells

Tumor-infiltrating lymphocytes (TILs) from biopsies of 9 selected patients with pT1pN0M0 renal cell carcinoma (RCC) were analyzed at the clonal level for phenotypic distribution, cytokine secretion profile and antitumor cell proliferation and cytotoxicity. T-cell clones generated from RCCs were able to produce higher amounts of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) than the corresponding clones derived from peripheral blood mononuclear cells, thus suggesting a recruitment into tumors of T cells with peculiar functions. Moreover, CD4+ T-cell clones generated from TILs of nuclear grading 2 (G2)-type RCC patients produced significantly higher amounts of IL-4 and IL-10 and lower amounts of IFN-gamma than the corresponding clones generated from G1-type RCC and 2 renal angiomyolipoma (AML) patients. In addition, T-cell clones generated from lymphocytes infiltrating the peritumoral areas of G2-type, but not those from G1-type, RCC patients produced higher and lower amounts of IL-4 and IFN-gamma, respectively, than the corresponding clones derived from intratumoral T cells of the same patients. The proportion of T-cell clones derived from G2-type tumors and proliferating to autologous tumor cells (ATCs) was significantly lower than that of clones generated from G1-type RCC or AML patients. However, irrespective of their source, they exhibited similar cytokine profiles and produced comparable amounts of IL-4, IL-10 and IFN-gamma. Furthermore, the proportion and the production of both IL-4 and IFN-gamma of G2-type RCC-derived T-cell clones with cytotoxic activity against ATC were significantly lower than those of cytolytic clones generated from AML and G1-type RCCs. The concentrations of IL-4, IL-10 and IFN-gamma produced by the cytolytic clones from G2-type RCC were also lower than those produced by their noncytolytic counterparts obtained from the same patients. These data address the association of the nuclear grading of neoplastic cells with different local tumor-specific T-cell responses in RCC.