Experimental evidence has shown that melatonin (MLT) may act through both membrane and nuclear receptors. Moreover, it was proposed that the nuclear MLT receptor is identical with nuclear orphan receptors called RZR/ROR. Our earlier results suggest that the antitumor action of MLT depends mainly on nuclear signaling. In the present study, we investigated whether CGP 55644 (an antagonist of the nuclear RZR/RORα receptor) changes the oncostatic effects of MLT on murine Colon 38 cancer. The experiment was performed on adult male B6D2F1 mice. MLT or CGP were given either alone or combined during 10 days, and cell proliferation, apoptosis and the proliferation/apoptosis (P/A) ratio were determined. Cell proliferation was assessed by incorporation of bromodeoxyuridine into tumor cell nuclei (labeling index – LI). The number of apoptotic cells using the TUNEL method was considered as an index of apoptosis. It was found that MLT inhibited cell proliferation. Addition of CGP to MLT diminished the antiproliferative effect of MLT. Moreover, MLT increased the apoptotic index, but CGP decreased apoptosis. In addition, CGP given together with MLT blocked its proapoptotic effect. Given alone, MLT strongly lowered the P/A ratio, and addition of CGP to MLT abolished the effect of MLT on the P/A ratio. Based on our data, we conclude that nuclear RZR/RORα receptors participate in the oncostatic action of MLT.

The effects of melatonin and the thiazolinidinedione derivative CGP 52608 on apoptosis of Colon 38 cancer cells were investigated. Male mice were implanted subcutaneously with a suspension of Colon 38 cells. Ten days after induction of tumors, the animals were treated with melatonin or CGP 52608. Both substances were given in subcutaneous injections in daily doses of 10 or 100 microg in the evening for 6 days. The control group received solvent. The apoptotic cells were visualized in paraffin sections by means of the transferase-mediated dUTPnick end-labeling method. Both treatments increased significantly and to the same degree the number of apoptotic cells in tumors. This finding confirms our earlier observation that melatonin exerts a pro-apoptotic effect on murine colonic cancer cells. Moreover, because CGP 52608 is a ligand of RZR/ROR receptors and the latter are considered by some investigators as nuclear binding sites for melatonin, our data suggest the involvement of these receptors in the pro-apoptotic effect of melatonin.

IntroductIon Hepatic encephalopathy is one of the symptoms of liver failure. The exact causes of encephalopathy are complex and still unclear. Apart from elevated blood ammonia levels, the role of numerous other factors is being considered. objectIves The aim of the study was to determine the serum level of serotonin and melatonin and the urinary excretion of their metabolites (5-hydroxyindoleacetic acid [5-HIAA] and 6-sulfatoxymelatonin [6-HMS]) in patients with various stages of liver cirrhosis. PAtIents And methods The study comprised 75 patients with alcohol-induced liver cirrhosis and 25 healthy subjects (control group). Based on the Child-Pugh classification, 3 groups of 25 patients each were distinguished-group A, B, and C with grade A, B, and C of liver failure, respectively. Blood samples were drawn at fasting at 9 a.m., and 24-hour urine collection was performed. Immunoenzymatic assays were used to determine serum melatonin and serotonin levels as well as urine 5-HIAA and 6-HMS concentrations. results Serum serotonin levels were 159.8 ±23.1 ng/ml in controls, 179.3 ±21.1 ng/ml in group A (P >0.05), 143.2 ±22.8 ng/ml in group B (P >0.05), and 114.5 ±37.6 ng/ml in group C (P <0.01). Serum melatonin levels were 10.6 ±1.7 in controls, 31.2 ±9.8 pg/ml in group A (P <0.01), 49.8 ±12.2 pg/ml in group B (P <0.001), and 94.8 ±22.6 pg/ml in group C (P <0.001). Urinary 5-HIAA excretion was 5.9 ±2.1 mg/24 h in controls, 5.9 ±1.9 mg/24 h in group A (P >0.05), 4.8 ±1.2 mg/24 h in group B (P >0.05), and 4.6 ±1.4 mg/24 h in group C (P <0.05). Urinary 6-HMS excretion was 26.6 ±15.1 μg/24 h in controls, 23.2 ±7.9 μg/24 h in group A (P >0.05), 18.3 ±10.6 μg/24 h in group B (P >0.05), and 6.5 ±3.6 μg/24 h in group C (P <0.001). conclusIon Disturbances in serotonin and melatonin homeostasis observed in patients with liver cirrhosis may be associated with advanced encopaholopathy.

Abstract:The effectiveness of the long acting somatostatin analogues like octreotide and lanreotide depends on the expression of specific somatostatin receptors on the target cells. The immunohistochemical method performed on surgically removed tumors searches the expression of receptors at the level of receptor protein and gives us insight into receptor's cellular localization. The aim of study was to assess the presence of all the 5 subtypes of SSTR 1-5 (including 2A and 2B SSTR isoforms) in surgically treated human neuroendocrine tumors (NETs) to establish which receptor subtype is the dominant form of somatostatin receptor in particular tumor and thus to be able to predict which somatostatin analog will be effective in NETs treatment. 18 samples of neuroendocrine tumors (surgically excised tumors or biopsies) were immunostained with specific antibodies. Expression of SSTR was scored semiquantitatively. Only strong or moderate immunostaining was considered as positive reaction. The summarized expression pattern of SSTR in the investigated neuroendocrine tumors in our material was: SSTR 1> SSTR 5> SSTR 3> SSTR 2A> SSTR 2B. The receptors were distributed mainly in the area of cells cytoplasm with a few specimens showing only membranous or mixed: membranous -cytoplasmic localization. The observed pattern suggests that apart from octreotide and lanreotide, newly synthesized multiligand analogs such as SOM 230, KE 108 or SSTR 1 and SSTR 5 selective analogs could be effective in NETs treatment.

Introduction: Follicle stimulating hormone receptors (FSHR) are well known to be expressed in gonads and in gonadal tumours. Recently, their incidence has also been revealed in endocrine non-gonadal tumours such as adrenal and pituitary tumours. Moreover, FSHR immunostaining has also been reported in endothelium of intra-and peritumoral blood vessels of a large series of cancers. The present paper reports on the incidence of FSHR in both tumoral cells and some intratumoral blood vessels of neuroendocrine tumours (NETs). Material and methods: Sixteen NETs samples were taken from 14 patients. The tumour samples were immunostained using the antibody raised against 1-190 amino acid sequence from the human FSH-R and anti-Ki67 antibody. Results: In all the samples examined, the majority of tumoral cells were immunostained with anti-FSHR antibody. Positive immunostaining concerned also the intratumoral blood vessels endothelia in a half of the examined samples. Immunopositive blood vessels were found more often in tumours with higher Ki-67 index.

No abstract

BackgroundIn normal conditions FSHR are expressed in granulosa cells of the ovary and Sertoli cells of the testis. They can be expressed also in gonadal tumours. However, recently the expression of FSHR was found in tumoral cells and intra-tumoral blood vessels of many other tumours, including thyroid tumours. Aim of this study was to see whether the expression of FSHR can be useful in the differentiation of benign and malignant thyroid lesions.Methods44 samples of surgically excised thyroids were immunostained with anti- FSHR antibody raised against 1–190 amino acid sequence from the human FSHR.ResultsNon-neoplastic thyroid follicles (i.e. the follicles situated outside the tumour) do not show the immunostaining for FSHR. The same concerns the majority of follicular adenomas. In contrast, 87.5% of follicular cancers, the same percentage of papillary cancers and all the examined undifferentiated cancers showed the FSHR immunopositivity of tumoral cells. A tendency towards the higher frequency of FSHR – positive blood vessels also concerns malignant thyroid tumours.ConclusionsThe ectopic FSHR immunostaining seems to be useful to differentiate malignant from benign lesions, especially follicular cancers from follicular adenomas. However, the further studies on larger material are needed.

IntroductionIn normal conditions follicle-stimulating hormone receptors (FSHR) are expressed in the ovary and the testis. They can also be expressed in gonadal tumors. However, recently we have found FSHR immunostaining in pituitary adenomas, adrenal tumors and neuroendocrine tumors (carcinoids). The aim of this study was to determine whether the same occurs in thyroid tumors.Material and methodsThirty-six samples of surgically excised thyroids were examined. Follicle-stimulating hormone receptors immunostaining was performed on paraffin sections using the rabbit anti-human FSHR polyclonal antibody raised against a 1-190 amino acid sequence from the human FSHR (sc-13935, Santa Cruz).ResultsNormal thyroid follicles do not show immunopositivity for FSHR. The same concerns the majority of benign lesions, diagnosed as hyperplasia nodularis or thyroid adenomas. However, positive FSHR immunostaining in some follicles was observed. In all but one thyroid cancer (15 papillary, 10 follicular cancers and one case of anaplastic thyroid cancer) 10–100% of tumor cells exhibit positive FSHR immunostaining. In about 40% of samples FSHR immunoreactivity can be observed also in the endothelia of intrathyroidal blood vessels. This immunopositivity was more frequent in the samples of thyroid cancers (13/27) than in benign lesions (2/9).ConclusionsEctopic positive FSHR immunostaining is also present in thyroid cancers, and, to a lesser degree, in benign lesions but not in the normal thyroid epithelium.