Benito Fraile

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

Nestin, a neuroectodermal stem cell marker molecule, is expressed in Leydig cells of the human testis and in some specific cell types from human testicular tumours.

The intermediate filament protein nestin is predominantly expressed in some stem/progenitor cells and appears to be a useful molecular tool to characterise tumours originating from precursor cells of neuroectodermal and mesenchymal lineages. Leydig cells originate in the adult testis by differentiation from stem cells and express a variety of neural and neuroendocrine markers. The possible expression of the neural stem cell marker nestin in Leydig cells and testicular tumour cells was determined by analysing the patterns of nestin expression in normal and pathological human testes by Western blot and immunohistochemical methods. In normal testis, nestin was found in some vascular endothelial cells, a subset of peritubular spindle-shaped cells and some Leydig cells; spermatogenic and Sertoli cells were unstained. In normal Leydig cells, nestin was distributed in the perinuclear cytoplasm and accumulated in the crystalloids of Reinke with ageing. In non-tumour pathologies (cryptorchidism, impaired spermatogenesis), the seminiferous tubules were immunonegative, whereas hyperplastic Leydig cells showed cytoplasmic immunolabelling. In testicular malignancies, nestin was localised in the Sertoli cells of the seminiferous tubules affected with intratubular germ cell neoplasia, in the hyperplastic Leydig cells associated with these tumours and in some components (mesenchymal and neuroepithelial cells) of teratomas; spermatocytic and non-spermatocytic seminomas were unstained. Some vascular endothelial cells were immunolabelled in all tumour samples. Thus, nestin is expressed in a population of normal and hyperplastic Leydig cells and in Sertoli cells in the presence of intratubular germ-cell neoplasia. Nestin may be a good marker for identifying components of testicular teratomas.

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.

MAP Kinases and Prostate Cancer

The three major mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK are signal transducers involved in a broad range of cell functions including survival, apoptosis, and cell differentiation. Whereas JNK and p38 have been generally linked to cell death and tumor suppression, ERK plays a prominent role in cell survival and tumor promotion, in response to a broad range of stimuli such as cytokines, growth factors, ultraviolet radiation, hypoxia, or pharmacological compounds. However, there is a growing body of evidence supporting that JNK and p38 also contribute to the development of a number of malignances. In this paper we focus on the involvement of the MAPK pathways in prostate cancer, including the less-known ERK5 pathway, as pro- or antitumor mediators, through their effects on apoptosis, survival, metastatic potential, and androgen-independent growth.

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.

Transforming Growth Factor β and its Receptor Types I and II. Comparison in Human Normal Prostate, Benign Prostatic Hyperplasia, and Prostatic Carcinoma

An immunohistochemical and semiquantitative comparative study of transforming growth factor beta 1 (TGF-beta 1) and its receptor types I (TGF-beta RI) and II (TGF-beta RII) was carried out in normal prostates and in the prostates from men with benign prostatic hyperplasia (BPH), and men with prostatic adenocarcinoma. Immunoreaction to TGF-beta 1 was limited to the basal epithelial cells in the normal prostates. Some cells in the connective tissue stroma were also stained. In BPH immunolabelling was also observed in columnar (secretory) cells of the epithelium. In prostatic adenocarcinoma, all epithelial cell types were intensely immunostained. Some stromal cells were also stained. Immunostaining to TGF-beta RI was only present in the basal cells in normal prostates. In BPH, this immunoreaction was found in the whole epithelium and in some stromal cells. In prostatic cancer, the immunostaining pattern for this receptor was similar to that of BPH but more intense in the epithelial cells. Immunoreactivity to TGF-beta RII appeared in some basal cells and some scattered columnar cells of the normal prostate epithelium. In the BPH sections, this pattern was maintained, and a weak immunolabelling was also observed in the stroma. In prostate cancer, all epithelial cells appeared intensely labelled. In the stroma, immunolabelling was similar to that of the BPH specimens. The results of the present study suggest that, in normal prostates, only the basal cells of the epithelium possess both receptor types, and hence can transduce TGF-beta 1 signal intracellularly. The basal cells can also secrete this growth factor which would act as an autocrine inhibitory growth factor for them. In addition, TGF-beta 1 is secreted in some zones by stromal cells, acting then as a paracrine growth factor for basal cells in those areas. In BPH, in addition to the basal cells, some secretory columnar cells also secrete TGF-beta 1 and possess both types of TGF-beta 1 receptors, and thus, both epithelial cell types are susceptible to TGF-beta 1 action. Since both receptor types are also present in some stromal cells, these cells also perform an autocrine secretion, in addition to their paracrine secretion to the epithelial cells. TGF-beta RIIs seem to be more numerous than TGF-beta RIs and this lead us to hypothesize that these incomplete receptors might be a protection against the inhibition caused by TGF-beta 1 action. In prostatic carcinoma all cell types display the same characteristics as in BPH, although both receptor types are found in similar numbers, and thus, the above mentioned protection would not occur.

TNF/IL-1/NIK/NF-κB transduction pathway: a comparative study in normal and pathological human prostate (benign hyperplasia and carcinoma)

Aims:  Tumour necrosis factor (TNF)‐α induces death or cell proliferation by activation of nuclear factor (NF)‐κB, also activated by interleukin (IL)‐1α. The aim was to investigate upstream and downstream components of NIK transduction pathway in normal (NP), benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN) and prostatic carcinoma (PC).

A lectin histochemistry comparative study in human normal prostate, benign prostatic hyperplasia, and prostatic carcinoma.

The partial oligosaccharide sequences of glycoconjugates and the nature of their glycosidic linkages were investigated in normal human prostate, benign prostatic hyperplasia (BPH) and prostatic carcinoma by means of lectin histochemistry, using light microscopy and Western blot analysis. The labeling pattern of BPH differed from that of normal prostate in having more intense staining with DSA, HPA, UEA-I and AAA, and in showing lesser staining with WGA and SBA. Prostatic carcinoma differed from normal prostates in displaying the more intense labeling with PNA, DSA, SBA, DBA, UEA-I and AAA, and in having lesser labeling with WGA. The main differences in labeling pattern between prostatic carcinoma and BPH were that the latter specimens showed more marked staining with PNA, DSA, DBA, SBA, UEA-I and AAA, and lesser staining with WGA and HPA. The staining patterns of SNA, MAA, ConA, LCA and GNA were similar in all three groups of specimens. For most of the lectins studied, including those showing a similar immunohistochemical staining in the three groups of specimens studied, the Western blot analysis showed differences in the banding pattern among normal, hyperplastic, and carcinomatous prostates. Present results suggest that the glycosylation of proteins was modified in both BPH and prostatic carcinoma. In BPH a strong expression of N-acetylgalactosamine residues occurred, while in prostatic carcinoma an increase of sialic aci, galactose and fucose residues was observed. No changes in mannose residues were detected.