Ignacio García-Tuñón

The p38 transduction pathway in prostatic neoplasia

It has been proposed that, among other cellular responses, TNF‐α induces not only cell death, but also cell proliferation by activation of p38. It has also been reported that IL‐1‐α favours cell proliferation by p38 activation. The aim of the present study was to evaluate upstream (α‐PAK, MEK‐6) and downstream (Elk‐1 and ATF‐2) components of the p38 transduction pathway in normal prostate, benign prostatic hyperplasia (BPH), and prostate carcinoma (PC). Immunohistochemical and western blot analyses were performed in 20 samples of normal prostate, 47 samples of BPH, and 27 samples of PC. In all normal prostates, immunoreactivity for p‐Elk‐1 and p‐ATF‐2 was observed in epithelial cell nuclei, but no expression of α‐PAK or MEK‐6. In BPH, there was expression of α‐PAK (cytoplasm) and MEK‐6 (cytoplasm), while the proportions of lesions that were immunoreactive for p‐Elk‐1 (nucleus and cytoplasm) and p‐ATF‐2 (nucleus) decreased. In PC, the percentages of cells that were immunoreactive for α‐PAK (cytoplasm) or MEK‐6 (cytoplasm) rose slightly in comparison with BPH, while the percentages of cells that were immunoreactive for p‐Elk‐1 (nucleus and cytoplasm) or p‐ATF‐2 (nucleus and cytoplasm) were much higher than in BPH. It is concluded that overexpression of α‐PAK, MEK‐6, p38, p‐Elk‐1, and p‐ATF‐2 in BPH, and more intensely in PC, enhances cell proliferation. In BPH, such proliferation is triggered by IL‐1 and in part counteracted by the TNF‐α/AP‐1 pathway, which promotes apoptosis. In PC, proliferation is triggered by IL‐1 and TNF‐α (the TNF‐α/AP‐1 pathway is diverted towards p38 activation). Since in a study of the same patients immunoexpression of IL‐1α and IL‐1RI was previously observed to be increased in PC, inhibition of p38 is a possible target for PC treatment, as this inhibition would both decrease IL‐1‐induced cell proliferation and increase TNF‐α‐induced cell death. Copyright

Immunohistochemical analysis of the IL-6 family of cytokines and their receptors in benign, hyperplasic, and malignant human prostate

Interleukin‐6 (IL‐6) and its receptor have been implicated in prostate cancer progression. Because other members of the IL‐6 family such as leukaemia inhibitory factor (LIF) and oncostatin M (OSM) share gp130, the signal transduction subunit of their receptors, interpretation of the data without considering the expression of these cytokines and their specific receptor subunits could be misleading. The immunohistochemical pattern of the IL‐6 family and their receptor subunits in normal prostate, benign prostatic hyperplasia (BPH), and prostatic carcinoma (PC) was investigated. In normal prostates, gp130 and OSMRα were detected exclusively in the stroma and LIFRβ was very scarce. While IL‐6 was scarcely immunolocalized to the basal cells of the epithelium, OSM was detected in the stroma and LIF in both the epithelium and the stroma. This suggests an autocrine role for this family of cytokines in the stroma of normal prostates. In BPH, gp130 and OSMRα were detected both in the epithelium and in the stroma, whereas LIFRβ was localized only to the epithelium. IL‐6 localized preferentially to the epithelium, OSM to the stroma, and LIF to both compartments. Therefore, in addition to the autocrine role in the stroma, IL‐6 and OSM may play a paracrine role from the stroma to the epithelium in BPH. In PC, gp130 and OSMRα were detected both in the epithelium and in the stroma, increasing with rising Gleason grade, whereas LIFRβ was localized exclusively to the epithelium of low Gleason grade carcinomas. IL‐6, LIF, and OSM localized in all cell types, with immunostaining increasing with Gleason grade. These data suggest an autocrine role for these cytokines in the epithelial cells of PC. The distinct pattern of expression of LIFRβ exclusively in low Gleason grade carcinomas makes LIFRβ a candidate for malignancy diagnosis. The role of OSM mainly in high Gleason grade carcinomas makes OSM a putative target for prostate cancer therapy. Copyright

Interleukin-1 (IL-1α and IL-1β) and its receptors (IL-1RI, IL-1RII, and IL-1Ra) in prostate carcinoma

The principal components of the interleukin‐1 (IL‐1) family are two secreted factors (IL‐1α and IL‐1β), two transmembrane receptors (IL‐1RI [biologically active] and IL‐1RII [inert receptor]), and a natural antagonist receptor of IL‐1 function (IL‐1Ra). Changes in the expression pattern of these IL‐1 members have been reported to be related to disease progression. The objective of the current study was to evaluate these changes in prostatic tissue by means of immunohistochemistry and Western blot analysis.

Role of tumor necrosis factor-α and its receptors in human benign breast lesions and tumors (in situ and infiltrative)

The aim of the present study was to characterize the expression pattern of tumor necrosis factor (TNF)‐α and its receptors in breast samples (benign diseases, in situ carcinomas and infiltrating carcinomas), and to compare these results with those obtained previously for interleukin‐6, p53 and p21 using the same samples in order to elucidate the effects of these cytokines on the proliferation–apoptosis equilibrium. Immunoexpression of TNF‐α and its receptors (TNFRI and TNFRII) were studied by western blotting and immunohistochemistry. The percentage of samples positive for TNF‐α and TNFRII was higher in in situ carcinoma than in benign breast diseases, and TNFRII was even higher in infiltrating tumors. The percentage of samples positive for TNFRI was similar in the three groups. For the three proteins and in the three patient groups, immunoreactions were observed in the peripheral cytoplasm. In the positive samples, immunostaining for TNF‐α was more intense in infiltrating tumors than in the other two patient groups, whereas immunostaining for both receptors was higher in in situ carcinoma than in benign breast diseases, and even higher in infiltrating tumors. Comparing the TNF‐α results with previous results for mtp53, p21 and interleukin‐6, we found an association between the expression of these four proteins and increasing malignancy. TNF‐α might be an important factor in breast cancer promotion as its proliferation and survival effects seems to be enhanced through the increased expression of TNFRII. Also, the pro‐apoptotic pathway of TNFRI could be inhibited by p21 (which appeared increased in breast cancer), altering TNFRI effects in promoting the expression of several factors, such interleukin‐6, which contribute to tumor promotion. (Cancer Sci 2006; 97: 1044–1049)

IL-6, its receptors and its relationship with bcl-2 and bax proteins in infiltrating and in situ human breast carcinoma

Aims : To characterize the expression pattern of IL‐6 and its receptors (IL‐6Rα and gp130), to relate this pattern to bcl‐2 and bax expression and to elucidate the effects on the proliferation/apoptosis equilibrium in benign conditions and in situ and infiltrating breast cancer.

Pro-inflammatory cytokines and prostate-specific antigen in hyperplasia and human prostate cancer

BACKGROUND The aim of this study was to relate the expression, analyzed by Western blot and immunohistochemistry, of several pro-inflammatory cytokines, including IL-1, IL-6 and TNF-alpha, with serum levels of prostate-specific antigen (PSA) in normal and pathologic (hyperplasia and cancer) prostate tissues to elucidate their possible role in tumor progression. We are also discussing the possible use of these cytokines as a potential therapeutic target. METHODS The study was carried out in 5 normal, 25 benign prostatic hyperplastic (BPH) and 17 cancerous human prostates (PC). Immunohistochemical and Western blot analysis were performed. Serum levels of PSA were assayed by an immulite autoanalyzer. RESULTS The most relevant results showed that in BPH, IL-1alpha, IL-6 and tumor necrosis factor (TNF) were only expressed in patients with PSA serum levels of 0-4 or 4-20 ng/ml, but not in the group >20 ng/ml. In PC these cytokines were only expressed in patients with PSA serum levels >4 ng/ml. CONCLUSIONS In PC there was an association between the high expression of pro-inflammatory cytokines (TNFalpha, IL-6, IL-1), elevated serum levels of PSA and cancer progression. A better understanding of the biologic mechanism of this association may provide new targets for therapy in these patients.

P38 MAPK protects against TNF-α-provoked apoptosis in LNCaP prostatic cancer cells

Purpose: One of the most relevant aspects in cell death regulation is the signalling of apoptosis by the serine/threonine kinases MAPKs. The aim of this study was to investigate the effects of TNF-α stimulation on MAPK activation, and the pro- or anti-apoptotic role of these kinases in LNCaP and PC3 cells. Material and methods: Treatments were carried out using several TNF-α concentrations, as well as specific pharmacological inhibitors of MAPKs. Apoptosis rates were evaluated by DAPI staining and flow cytometry. MAPK phosphorylation/activation was measured by Western blot. Results: TNF-α induced apoptosis in a dose-dependent manner in LNCaP but not in PC3 cells. The MAPK inhibitors revealed that the apoptotic rate in LNCaP cells increased significantly following p38 inhibition. The kinase inhibitors failed to cause changes in apoptosis in PC3 cells. Conclusions: The potentiation of apoptosis by p38 inhibition points to this kinase as a possible target for the treatment of androgen-dependent prostatic cancer.

Interleukin-2 and its receptor complex (α, β and γ chains) in in situ and infiltrative human breast cancer: an immunohistochemical comparative study

IntroductionThe presence and distribution of interleukin-2 (IL-2) and its receptor complex (Rα, Rβ, Rγ) were studied in 52 women who were clinically and histopathologically diagnosed with breast tumours (17 in situ and 35 infiltrating), and in 13 women with benign fibrocystic lesions in the breast.MethodsImmunohistochemistry with antibodies against IL-2, IL-2Rα, IL-2Rβ and IL-2Rγ was used. A comparative semiquantitative immunohistochemical study between the three breast groups (fibrocystic lesions, in situ tumours and infiltrating tumours) was performed.ResultsIL-2 and its three receptor chains were immunodetected in the cytoplasm of epithelial cells. The three receptor chains were also detected on the cell surface. In fibrocystic lesions, immunoreactions to IL-2 (38.5% of cases), IL-2Rα (53.8%) and IL-2Rβ (30.8%) were very weak, whereas immunoreaction to IL-2Rγ (46.1%) was somewhat more intense. In in situ tumours, the percentages of cases that immunostained positively for IL-2 and its three receptor chains were similar to those observed in fibrocystic lesions, but immunostainings of the four antibodies were more intense. In infiltrative tumours, the percentages of positively stained cases and also immunostaining intensities were approximately twice that found for in situ tumours. Within infiltrating tumours, the percentage of cases showing immunoreaction to IL-2 and their three receptor chains was higher in the patients with lymph node infiltration at the time of surgery.ConclusionThe development of breast tumour is associated with an increased expression of IL-2 and its three receptor chains, and this expression also seems to be associated with the malignancy of the tumour.

OSM, LIF, Its Receptors, and Its Relationship with the Malignance in Human Breast Carcinoma (In Situ and in Infiltrative)

IL-6 cytokine family is composed by several members. IL-6, LIF, and gp130 have been associated with cancer progression. Cytokines play an important role in tumoral growth, invasion of the vessels and development of metastases. Immunoexpressions of LIF, OSM, LIFRβ and OSMRβ were studied in benign breast lesion, in situ and infiltrating tumors by Western blot and immunohistochemistry. Percentages of positive samples to OSM, LIF and OSMRβ were higher in in situ carcinoma than in benign diseases and even higher in infiltrating tumors. gp130-positive samples was higher in infiltrating tumor than in benign diseases. All samples studied were LIFRβ-positive. Infiltrating tumors showed the most intense immunostaining to LIFRβ, OSM and OSMRβ; comparing present results revealed an association between the expression of these proteins and increasing malignancy. In conclusions, development of breast tumor increases the expression of OSM, LIF, OSMRβ, LIFRβ and gp130, and this expression may be associated with the malignancy. IL-6 family exert their action through transducer receptor gp130, and gp130 expression increase with malignance, it might be a crucial point in the development of infiltrative adenocarcinoma. The secretion of OSM and LIF by both epithelial and stromal (paracrine manner) cells seems to promote tumor growth.

Influence of IFN-gamma and its receptors in human breast cancer

BackgroundInterferons are a group of proteins that trigger multiple responses including prevention of viral replication, inhibition of cell growth, and modulation of cell differentiation. In different mammary carcinoma cell lines IFNγ induces growth arrest at mid-G1. At the present there are no in vivo studies in human breast. The aim of this study was to investigate the expression patterns of IFNγ and its two receptors (IFNγ-Rα and IFNγ-Rβ) by Western blot and immunohistochemistry, in order to elucidate its role in the different types of human breast cancer (in situ and infiltrative).MethodsImmunohistochemical and semiquantitative study of IFNγ, its receptors types (IFNγ-Rα and IFNγ-Rβ), cell proliferation (proliferating cell nuclear antigen, also named PCNA), and apoptosis (TUNEL method) was carried between the three breast groups (fibrocystic lesions, in situ tumors and infiltrating tumors).ResultsIn the three groups of patients, IFNγ and IFNγ-Rα immunoreactions appeared in the cytoplasm while IFNγ-Rβ also was found in the nucleus. The optical density to IFNγ was higher in in situ carcinoma than in benign and infiltrating tumors. When we observed IFNγ-Rα, the optical density was lower in infiltrating carcinoma than in benign and in situ tumors (the higher density). To IFNγ-Rβ, the optical density was similar in the three group samples. In tumor samples PCNA and TUNEL index was significantly higher; than in benign diseases. PCNA index increased with the malignance. No significant differences were found between cancer types to TUNEL. IFNγ could be a potential therapeutic tool in breast cancer. However, tumor cells are able to escape from the control of this cytokine in the early tumor stages; this is probably due to a decreased expression of IFNγ, or also to an alteration of either its receptors or some transduction elements.ConclusionWe conclude that the decrease in the % positive samples that expressed IFNγ and IFNγ-Rα together with the nuclear localization of IFNγ-Rβ, could be a tumoral cell response, although perhaps insufficient to inhibit the uncontrolled cell proliferation. Perhaps, IFNγ might be unable to activate p21 to stop the cell cycle, suggesting a possible participation in breast cancer development.