Soluble tumor necrosis factor receptor expression in patients with metastatic renal cell carcinoma treated with interleukin-2-based immunotherapy

Heterogeneous effects of tissue inhibitors of matrix metalloproteinases on cardiac fibroblasts

The balance between matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), plays a critical role in cardiac remodeling. Although a number of studies have characterized the pathophysiological role of MMPs in the heart, very little is known with respect to the role of TIMPs in the heart. To delineate the role of TIMPs in the heart we examined the effects of adenovirus-mediated overexpression of TIMP-1, -2, -3, and -4 in cardiac fibroblasts. Infection of cardiac fibroblasts with adenoviral constructs containing human recombinant TIMP (AdTIMP-1, -2, -3, and -4) provoked a significant (P < 0.0001) 1.3-fold in increase in bromodeoxyuridine (BrdU) incorporation. Similarly, treatment of cardiac fibroblasts with AdTIMP-1-, -2-, -3-, and -4-conditioned medium led to a 1.2-fold increase in BrdU incorporation (P < 0.0001) that was abolished by pretreatment with anti-TIMP-1, -2, -3, and -4 antibodies. The effects of TIMPs were not mimicked by treating the cells with RS-130830, a broad-based MMP inhibitor, suggesting that the effects of TIMPs were independent of their ability to inhibit MMPs. Infection with AdTIMP-1, -2, -3, and -4 led to a significant increase in alpha-smooth muscle actin staining, consistent with TIMP-induced phenotypic differentiation into myofibroblasts. Finally, infection with AdTIMP-2 resulted in a significant increase in collagen synthesis, whereas infection with AdTIMP-3 resulted in a significant increase in fibroblast apoptosis. TIMPs exert overlapping as well as diverse effects on isolated cardiac fibroblasts. The observation that TIMPs stimulate fibroblast proliferation as well as phenotypic differentiation into myofibroblasts suggests that TIMPs may play an important role in tissue repair in the heart that extends beyond their traditional role as MMP inhibitors.

Serum Levels of IL-1b, IL-6, TNF-a, sTNF-RI and CRP in Patients with Oral Cavity Cancer

Pro-inflammatory cytokines, such as interleukin-1b (IL-1b), interleukin-6 (IL-6) and tumor necrosis factor- (TNF-a) play an essential role in the regulation of immune response to, and may have prognostic significance in, cancer. The aim of this study was to examine the relationship between the serum levels of IL-1b, IL-6 and TNF-a as well as the concentrations of soluble TNF receptor I (sTNF-RI) and C-reactive protein (CRP) in patients with squamous cell carcinoma of oral cavity. Results obtained were confronted with squamous cell carcinoma antigen (SCC) concentrations. IL-1b IL-6 and TNF-a serum levels as well as sTNF-RI and CRP concentrations were higher in patients than in controls. The increased serum levels appeared to be related to the clinical stage of disease. There was a correlation between IL-1b and sTNF-RI. IL-6 and IL-1b correlated with CRP levels. The mean concentrations of SCC were also elevated. IL-6 and sTNF-RI seemed to be the most sensitive parameters in early stages and may be used as additional markers in oral cancer.

Multifaceted inhibition of anti-tumour immune mechanisms by soluble tumour necrosis factor receptor type I

Soluble tumour necrosis factor receptor type I (sTNFRI) is a potent inhibitor of TNF with the potential to suppress a variety of effector mechanisms important in tumour immunity. That sTNFRI influences tumour survival in vivo is suggested by results from human clinical trials of Ultrapheresis, an experimental extracorporeal treatment for cancer. While the considerable clinical benefit provided by Ultrapheresis is correlated with the removal of plasma sTNFRI, there is no direct evidence that sTNFRI inhibits immune mechanisms which mediate tumour cell elimination. To evaluate formally the ability of sTNFRI to inhibit these mechanisms, we have engineered sTNFRI production into the TNF-sensitive murine fibrosarcoma cell line, L929. Soluble TNFRI-secreting L929 cells display increased resistance to direct lysis by TNF, and to lysis by syngeneic lymphokine-activated killer cells and cytotoxic T cells. These findings confirm the suggestion that sTNFRI inhibits immunological mechanisms important in tumour cell eradication, and further support a role for sTNFRI in tumour survival in vivo. In addition, these observations suggest the development of methods for more specific removal and/or inactivation of sTNFRI as promising new avenues for cancer immunotherapy.

Increased release of the tumour necrosis factor receptor p75 by immortalized human keratinocytes results from an activated shedding mechanism and is not related to augmented steady-state levels of p75 mRNA

The soluble tumour necrosis factor receptor I (sTNFRI, p55) is produced at similar levels by both immortalized (A431, HaCaT, KB) and primary normal human keratinocytes (HNK), whereas the soluble TNFR II (sTNFR II, p75) appears to be specifically released only by immortalized human keratinocytes. The purpose of this study was to investigate whether the increase in p75 secretion by immortalized human keratinocytes is due to an increased shedding of the receptor from the cell membrane, or is related to increased steady-state levels of p75 mRNA. FACS analysis showed that levels of membranous p75 decreased in a time-dependent manner in immortalized cells cultured for 1, 3, 6, 12 and 24 h, while remaining unchanged in HNK throughout. Northern blot analysis showed that after 12 h of culture, when p75 expression was decreased on the cell membrane of all immortalized cells, there was no significant difference in steady state levels of p75 mRNA between immortalized keratinocytes and HNK. Supernatants of immortalized cells, cultured for 24 h contained distinct levels of p75, while levels of p75 in supernatants of HNK were under the detection limit, confirming that the p75 decrease on the cell membrane results from increased p75 shedding from the cell membrane of immortalized cells. In contrast to p75, p55 was continuously expressed on the cell membrane of normal and immortalized keratinocytes without significant variation throughout the entire 24-h culture period and was similarly shed by both cell types. These results suggest that immortalized keratinocytes are specifically activated for shedding of p75 from the cell membrane. Since p75 has a high affinity for TNF, the release of this receptor may imply a direct role in the escape of malignant/transformed keratinocytes from the TNF-mediated immune response.

Soluble interleukin-6 receptors in hematology patients undergoing bone marrow transplantation

Soluble interleukin-6 receptor (sIL-6R) has previously been shown to potentiate the activity of interleukin (IL)-6, which may display antitumor activity. We evaluated sIL-6R and IL-6 levels in the sera of 24 patients following transplantation (allogeneic, n=17; autologous, n=7). Five patients developed acute graft-versus-host disease (AGVHD), three had early graft rejection, and three had an early relapse following bone marrow transplantation (BMT). Soluble IL-6R levels were evaluated at day - 10, day 0, day of engraftment, and during BMT-related complications, using IL-6R-specific monoclonal antibodies (mAb) and double-sandwich ELISA. In normal controls, sIL-6R and IL-6 levels were 20+/-3 ng/ml and 0.01+/-0.005 ng/ml, respectively. Soluble IL-6R levels increased in direct correlation with engraftment in the uneventful allogeneic transplants (17.7+/-2.1 ng/ml at day 0 to 49.7+/-2.6 ng/ml at day of engraftment, n=6, P<0.05) as well as in the autologous transplants (26.8+/-2.82 at day 0 to 66.4+/-12.9 at day of engraftment, n=5, P=0.01). In contrast, IL-6 levels declined with time during the conditioning period and showed only a modest elevation following BMT. Increased levels of sIL-6R and IL-6 were found in the patients who developed AGVHD (23.8+/-4.2 and 0+/-0 ng/ml at day 0 to 79+/-6.9 and 0.26+/-0.04 ng/ml, respectively, at time of AGVHD, n=5, P=0.01). No correlation was found between the severity of AGVHD and sIL-6R levels. In the three patients with early relapse, sIL-6R levels increased from 30+/-0 ng/ml at day 0 to 90 ng/ml (P=0.05) and IL-6 levels increased from 0 to 0.16+/-0 ng/ml, respectively. The mean elevation of sIL-6R in the patients with early relapse and AGVHD was significantly higher than the mean elevation in the patients with the relatively smooth engraftment (P<0.05). Contrary to these findings, in the three patients with graft rejection, sIL-6R levels decreased while IL-6 was found to be elevated. Basic disease, conditioning regimen, type of transplant, GVHD propylaxis, and T cell depletion had no effect on sIL-6R or IL-6 levels. In summary, sIL-6R levels positively correlated with engraftment. Both sIL-6R and IL-6 levels were found to be significantly elevated in patients who developed AGVHD or early relapse following BMT. Therefore, the sIL-6R level may be used as a tool for assessing engraftment and transplant-related complications following BMT.

Soluble receptors for tumour necrosis factor in clinical laboratory diagnosis

Soluble tumour necrosis factor receptors (sTNF-Rs) play a role as modulators of the biological function of tumour necrosis factor-alpha (TNF-alpha) in an agonist/antagonist pattern. In various pathologic states the production and release of sTNF-Rs may mediate host response and determine the course and outcome of disease by interacting with TNF-alpha and competing with cell surface receptors. The determination of sTNF-Rs in body fluids such as plasma or serum is a new tool to gain information about immune processes and provides valuable insight into a variety of pathological conditions. Regarding its immediate clinical use, sTNF-Rs levels show high accuracy in the follow-up and prognosis of various diseases. In HIV infection and sepsis, sTNF-Rs concentrations strongly correlate with the clinical stage and the progression of disease and can be of predictive value. Determination of sTNF-Rs also gives useful information for monitoring cancer and autoimmune diseases. The information provided is often even superior to that obtained with classical disease markers, probably due to the direct involvement of the "TNF system" in the pathogenetic mechanisms in these patients. The available data imply that the measurement of sTNF-Rs, especially of the sTNF-R 75kD type, is a useful adjunct for quantification of the Th1-type immune response, similar to other immune activation markers such as neopterin and beta 2-microglobulin. Endogenous sTNF-Rs concentrations appear to reflect the activation state of the TNF-alpha/TNF receptor system.

Serum levels of cytokines and soluble cytokine receptors in patients with metastatic renal cell carcinoma or malignant melanoma receiving IL-2/interferon-alpha combination therapy

Elevated serum levels of soluble tumour necrosis factor receptor (sTNFR-55) and (at a lesser degree) of sTNFR-75 were found in most of the patients with metastatic renal cell carcinoma (RCC) or malignant melanoma (MM) before immunotherapy and with further increase during treatment (intravenous infusions of interleukin-2 [IL-2] and subcutaneous interferon-alpha [IFN-alpha]). In the majority of the patients with MM the pretreatment serum levels of IL-2 and soluble IL-2 receptor (sIL-2R) were increased, whereas fewer patients with RCC presented with increased serum levels of IL-2 and sIL-2R. Twelve days' treatment with IL-2/IFN-alpha, with a rest on days 6 and 7, resulted in a consistent further increase in the serum levels of sIL-2R and sTNFRs. In most patients the increase of sIL-2R and sTNFRs lasted for at least 3 weeks after treatment discontinuation. The clinical significance of the increase remains unknown.