Elevated serum concentrations of IGF-1 and IGF-1R in patients with thyroid cancers

BACKGROUND

The rising incidence of thyroid cancer observed in the last few decades requires an improvement in diagnostic tools and management techniques for patients with thyroid nodules.

AIMS

The aim of this study was to assess serum concentrations of IGF-1 and IGF-1R in patients diagnosed with thyroid cancers.

METHODS

36 patients diagnosed with papillary thyroid cancer (PTC), 11 subjects with follicular thyroid cancer (FTC), 9 patients with anaplastic thyroid cancer (ATC) and 19 subjects with multinodular nontoxic goiter (MNG) were enrolled to the study. The control group (CG) consisted of 20 healthy volunteers. Blood samples were collected one day before surgery. Serum IGF-1 and IGF-1R concentrations were measured using specific ELISA methods.

RESULTS

Significantly higher concentrations of IGF-1 were found in patients with PTC as compared with controls but not that obtained from subjects diagnosed with MNG. The concentration of IGF-1R was significantly elevated in subjects with PTC and ATC as compared with healthy volunteers. Similarly, patients diagnosed with PTC or ATC presented significantly higher serum concentration of IGF-1R in comparison to the MNG group.

CONCLUSIONS

Our results show that the IGF-1 - IGF-1R axis plays a significant role in the development of PTC and ATC and imply that serum concentrations of both cytokines may be considered as additional markers for the differentiation of malignancies during the preoperative diagnosis of patients with thyroid gland tumors. These results indicate that IGF-1R serum concentrations allow us to differentiate between MNG and PTC or ATC. Moreover IGF-1R serum values appear to be better predictor of PTC and ATC than IGF-1 concentrations.

Estimation of vitamin D status in patients with secondary and primary hypothyroidism of different etiology

BACKGROUND

Though vitamin D deficiency is a global problem with wide spectrum of severe public health consequences, inadequate vitamin D status still remains one of the most common and untreated medical conditions. Thyroid diseases, including hypothyroidism, also represent the most frequent endocrinopathies in general population.

OBJECTIVES

To determine the vitamin D status in hypothyroid patients and to ascertain the status of thyroid hormone replacement.

METHODS

The 25(OH)D concentrations (ECLIA) in 71 hypothyroid patients recruited in the Outpatient Clinic of Endocrinology or Department of Clinical Endocrinology were assessed. The examined group was composed of 59 subjects diagnosed with primary hypothyroidism of different etiology and 12 patients with secondary hypothyroidism. The control group included 16 healthy individuals.

RESULTS

Mean serum 25(OH)D concentration in healthy volunteers was significantly lower than in hypothyroid subjects (13.09±1.63 vs. 19.92±1.37 ng/mL). Patients with a history of thyroidectomy presented with significantly higher mean 25(OH)D concentration than controls (23.25±2.75 vs. 13.09±1.63 ng/mL). Mean serum 25(OH)D concentration in effectively treated hypothyroidism was significantly higher than in controls (21.90±1.47 vs. 13.09±1.63 ng/mL) or undertreated hypothyroidism (21.90±1.47 vs. 13.52±3.39 ng/mL). Hypothyroid patients aged under 60 years presented with significantly lower mean 25(OH)D concentration than elders (16.46±1.54 vs. 24.39±1.18 ng/mL). The major 25(OH)D deficient (≤10 ng/mL) or deficient (≤20 ng/mL) hypothyroid patients were significantly younger than those with 25(OH)D concentrations exceeding 10 ng/mL or 20 ng/mL respectively.

CONCLUSIONS

These findings confirm the necessity for vitamin D status improvement in the general population and more effective healthcare of hypothyroid patients.

Somatostatin Analogs and Tumor Localization Do Not Influence Vitamin D Concentration in Patients with Neuroendocrine Tumors

Patients with neuroendocrine tumors (NETs), malignancies of rare but still rising incidence, may be a group at higher risk of vitamin D insufficiency. The gastrointestinal tumor prevalence and somatostatin analog (SSA) therapy may cause vitamin D malabsorption. The aim of this study was to evaluate the serum level of vitamin D in NET patients. A total of 36 NET patients were enrolled into the experimental group and 16 individuals were enrolled into the control group. All patients were further classified into subgroups according to primary tumor localization (gastropancreatic, lung, and other NETs) or therapy (with or without SSA treatment). The concentrations of total 25(OH)D were assayed with Electrochemiluminescence immunoassay (ECLIA). Serum concentration of 25(OH)D in NET patients did not differ significantly from that of the control group. However, the average level of 25(OH)D in both groups met the criteria of vitamin D deficiency. Importantly, SSA therapy did not aggravate vitamin D deficiency. Moreover, the concentration of 25(OH)D in the studied group was not significantly influenced by primary tumor localization, patient age, or season. Vitamin D deficiency is a widespread disorder affecting both NET patients and individuals without other health problems, and SSA and gastrointestinal tumor localization do not exacerbate this condition.

Interferon alpha and rapamycin inhibit the growth of pheochromocytoma PC12 line in vitro

INTRODUCTION

Pheochromocytomas are benign or malignant neuroendocrine tumours. The unsatisfactory efficacy of the traditional therapeutic methods for patients with metastatic disease results in a continuing search for more effective and targeted agents. Due to the increased vascularisation of these tumours, inhibitors of angiogenesis could be potentially a new group of drugs in pheochromocytoma/paraganglioma therapy.

MATERIAL AND METHODS

The aim of this study was to evaluate the influence of angiomodulators: VEGF (vascular endothelial growth factor) and five endogenous and exogenous antiangiogenic compounds (endostatin; IFN-alpha [interferon alpha]; rapamycin - mTOR [mammalian target of rapamycin] inhibitor; JV1-36 and SU5416 (semaxinib]) on the growth of rat pheochromocytoma PC12 cell line.

RESULTS

IFN-alpha (10(5) U/mL) strongly inhibited PC12 growth in a 72 h culture, increasing apoptosis and arresting the cell cycle. Rapamycin in a wide range of concentrations (10(-5) to 10(-8) M) induced a slight inhibitory effect on PC12 viability and decreased cell proliferation at the concentration of 10(-5) M. VEGF, endostatin and JV1-36 did not influence the growth of PC12.

CONCLUSIONS

The study has shown for the first time that IFN-a inhibited the growth of pheochromocytoma PC12 line and confirmed the inhibitory action of rapamycin on these cells. The results suggest that IFN-alpha and mTOR inhibitors could be potentially effective in the therapy of malignant pheochromocytoma, and encourage further study in this field.

Interferon alpha and rapamycin inhibit the growth of carcinoid and medullary thyroid cancer in vitro

Neuroendocrine tumors (NETs) are highly vascularized neoplasms characterized by rising incidence. Moreover, the neuroendocrine cells were shown to express vascular endothelial growth factor (VEGF) and VEGF receptors. Therefore, angiomodulators could be potentially a new group of drugs enhancing still unsatisfactory effectiveness of NET therapy. The aim of this study was to assess the direct influence of angiomodulators: VEGF and five endogenous and exogenous antiangiogenic compounds (endostatin, interferon alpha [IFNα], rapamycin, JV1-36, semaxinib [SU5416]) on the growth of two NET cell lines: lung carcinoid H727 cell line and medullary thyroid cancer TT cell line in vitro. IFNα and rapamycin induced the inhibitory effect on H727 and TT cell viability and proliferation, increasing apoptosis and arresting the cell cycle. Also semaxinib (10(-5)M) inhibited proliferation of both cell lines. VEGF and endostatin did not influence the growth of H727 and TT cells. The inhibitory effect of IFNα, rapamycin and semaxinib on carcinoid and medullary thyroid cancer growth was revealed in our in vitro study, although some other antiangiogenic agents did not directly influence H727 and TT cell growth. Thus, IFNα and mTOR inhibitors as multidirectionally acting drugs with antiangiogenic effect could be potentially efficient in treatment of neuroendocrine tumors and are worth further studies.

Modulation of ghrelin axis influences the growth of colonic and prostatic cancer cells in vitro

BACKGROUND

The risk of different cancers seems to be associated with obesity. Moreover, low ghrelin levels observed in obese people may be implicated in cancer development and progression. The aim of this study was to examine the direct effects of both forms of ghrelin (acylated and unacylated) and ghrelin receptor type 1a antagonist (D-Lys-GHRP-6) on the growth of murine colon cancer MC38 and human prostate cancer DU145 cell lines in vitro.

METHODS

The cells were cultured for 72 h in the presence of rat or human acylated ghrelin (rG, hG), human unacylated ghrelin (hUAG), D-Lys-GHRP-6 (GHS-RA) applied either alone or jointly. The cell line growth was assessed by the colorimetric Mosmann method.

RESULTS

hUAG (10(-6), 10(-7) and 10(-10) M) inhibited MC38 cancer cell growth and, at some concentrations (10(-8), 10(-9), 10(-10) M), enhanced the antineoplastic effect of GHS-RA(10(-4) M). In turn, GHS-RA evoked a biphasic effect on MC38 cancer growth: inhibitory at 10(-4) M and stimulatory at 10(-5) and 10(-6) M. Moreover, GHS-RA at the highest examined concentration (10(-4) M) enhanced the cytostatic effect of FU. Human acylated and unacylated ghrelin and GHS-RA inhibited DU145 cancer growth with moderate and different potencies. A dose-response effect was observed for the inhibitory action of hG together with the synergistic effect of hUAG and GHS-RA.

CONCLUSION

The obtained results indicate an involvement of the ghrelin axis in the growth regulation of colon and prostate cancers and may suggest new therapeutic options for these neoplasms.

The effects of angiotensin peptides and angiotensin receptor antagonists on the cell growth and angiogenic activity of GH3 lactosomatotroph cells in vitro

The local renin-angiotensin system (RAS) is present in the pituitary gland, and inhibitory effects of angiotensins on the lactosomatotroph (GH3) cell growth have been revealed. The aim of this study was to examine the influence of various angiotensin peptides and angiotensin AT1, AT2, and AT4 receptors antagonists on the cell proliferation, viability, and VEGF secretion in pituitary lactosomatotroph GH3 cell culture in order to identify receptors involved in antiproliferative effects of angiotensins on GH3 tumor cells. Cell viability and proliferation using Mosmann method and BrdU incorporation during DNA synthesis, and VEGF secretion using ELISA assay were estimated. The inhibitory effects of ang II, ang IV, and ang 5-8 on the cell viability and BrdU incorporation in GH3 culture were not abolished by AT1, AT2, and AT4 receptors antagonists. Ang II, as well as ang III and ang IV at lower concentrations stimulated the secretion of VEGF in GH3 cell culture. The secretion of VEGF was inhibited by ang III and ang IV at higher concentrations. AT1 and AT2 receptors antagonists prevented the proangiogenic effects of ang II. Ang II, ang IV, and ang 5-8 decrease the cell number and proliferation in GH3 cell culture independently of the AT1, AT2, and AT4 receptors. These peptides affect also secretion of VEGF in culture examined. Both the AT1 and AT2 receptors appear to mediate the proangiogenic effects of ang II.

The involvement of angiotensin type 1 and type 2 receptors in estrogen-induced cell proliferation and vascular endothelial growth factor expression in the rat anterior pituitary

The aim of our study was to examine the involvement of renin-angiotensin system (RAS) in estrogen-induced lactotropes proliferation and vascular endothelial growth factor (VEGF) expression in rat pituitary. The study was performed on Fisher 344 rats underwent 8-day treatment with diethylstilboestrol (DES). The proliferation index (PCNA) and VEGF expression in pituitary sections were estimated using immunohistochemical methods. Treatment with DES increased the number of PCNA-positive cells, VEGF-positive cells, and VEGF-positive blood vessels in pituitary. Stimulatory effect of estrogen on cell proliferation and VEGF expression in blood vessels was attenuated by losartan, PD123319, and captopril. VEGF immunoreactivity in pituitary cells of DES-treated rats was decreased by AT1 antagonist and not changed by AT2 blocker and ACE inhibitor. Our findings suggest the involvement of RAS in DES-induced cell proliferation and VEGF expression in pituitary. Both the AT1 and AT2 receptors appear to mediate the estrogen-dependent mitogenic and proangiogenic effects in rat pituitary.

Angiotensins inhibit cell growth in GH3 lactosomatotroph pituitary tumor cell culture: a possible involvement of the p44/42 and p38 MAPK pathways

The local renin-angiotensin system is present in the pituitary. We investigated the effects of angiotensins on GH3 lactosomatotroph cells proliferation in vitro and the involvement of p44/42 and p38 MAPK inhibitors in the growth-regulatory effects of angiotensins. Materials and Methods. Cell viability using the Mosmann method and proliferation by the measurement of BrdU incorporation during DNA synthesis were estimated. Results. Ang II and ang IV decreased the viability and proliferation of GH3 cells. Inhibitor of p44/42 MAPK attenuated the effects of ang II on cell viability and proliferation but did not affect the ang 5-8-dependent actions. Inhibitor of p38 MAPK prevented the decrease in the number of GH3 cells in ang-II- and ang-IV-treated groups. Conclusions. The growth-inhibitory effect of ang II is possibly mediated by the p44/42 MAPK. The p38 MAPK appears to mediate the inhibitory effects of both ang II and ang 5-8 upon cell survival.

Osteopontin and endostatin concentrations in peripheral blood of patients with adrenal tumors undergoing unilateral adrenalectomy

Peripheral blood osteopontin (OPN) and endostatin (END) levels were studied in 35 patients with adrenal cortex tumors and 10 patients with pheochromocytoma before unilateral adrenalectomy, as well as in 10 healthy subjects (controls). Thirty days after surgery, OPN and END were evaluated again in 16 patients with adrenal cortex tumors and 4 female patients with pheochromocytoma. Before surgery, OPN blood concentrations increased in the group of patients with adrenal cortex carcinomas as compared to controls (p < 0.001) and the group with Conn syndrome (p < 0.05); they did not change after surgery. Before adrenalectomy, OPN blood levels in pheochromocytoma patients were also lower than in Conn syndrome subjects (p < 0.05). After adrenalectomy, the normal concentrations of END decreased only in the group of patients with hormonally inactive cortical adenomas (p < 0.05). We were unable to demonstrate any relationships between removed tumor volumes and OPN or END blood levels.

Decreased 1-25 dihydroxyvitamin D3 concentration in peripheral blood serum of patients with thyroid cancer

BACKGROUND AND AIMS

Vitamin D(3), in addition to its role in calcium homeostasis, has been recognized as playing a role in human cancer development. However, little is known about the association between vitamin D status and the development of thyroid cancer. This study aimed to investigate vitamin D metabolism by measuring 25(OH) D(3), 1-25 (OH)(2) D(3), PTH and calcium concentrations in the peripheral blood of patients with different forms of thyroid tumors.

METHODS

The 25-hydroxyvitamin D(3) ,1-25- dihydoxyvitamin D(3), PTH and calcium serum levels of 50 consecutive patients with epithelial thyroid cancer 27 cases of papillary cancers (PTC), 16 follicular cancers (FTC), and seven cases of anaplastic cancers (ATC) and 34 multinodular nontoxic goiter (MNG) were measured by specific immunoassay. The control group consisted of 26 healthy volunteers.

RESULTS

Our results revealed significantly lower 1-25 (OH)(2) D(3) concentration in the PTC group (22.67 pg/mL +/- 8.12; p <0.05), FTC group (16.09 pg/mL +/- 6.15; p <0.02) and ATC group (9.48 pg/mL +/- 5.18; p <0.02). Levels of 1-25 (OH)(2) D(3) varied by cancer stage and were also significantly different. A significant decrease in circulating 1-25 (OH)(2) D(3) concentration was found in patients with stage I (24.12 pg/mL +/- 6.77; p <0.05), stage II (16.93 pg/mL +/- 4.55; p <0.05), stage III (12.44 +/- 8.98; p <0.02) and in stage IVa (6.18 +/- 2.22; p <0.01). There were no significant differences when comparing serum levels of 25(OH) D(3), PTH or calcium concentrations among individuals with multinodular goiter, thyroid cancer and age- and sex-matched control volunteers.

CONCLUSIONS

Our study revealed that impaired vitamin D(3) metabolism may play an important role in thyroid follicular cell oncogenesis.

Resorcylic acid lactone L-783,277 inhibits the growth of the human adrenal cancer cell line H295R in vitro

The resorcylic acid lactone L-783,277, isolated from a Phoma sp. (ATCC 74403), is a potent and specific inhibitor of MEK (Map kinase kinase) that exerts very interesting pharmacological activities including anti-neoplastic properties. However, the role of this compound in the regulation of endocrine-related cancer cell growth and tumor progression remains unknown. In the present study we have evaluated the effect of L-783,277 on the viability, proliferation and cell cycle of the human adrenocortical carcinoma cell line H295R. L-783,277 inhibited viability (IC50 of 22 microM) and cell proliferation (IC50 of 21 microM) of H295R. At concentrations of 10(-6)-10(-8)M this effect was associated with the accumulation of H295R cells in S-phase, whereas at concentrations of 10(-9)-10(-10)M a prolonged G1-phase and reduced transition into S-phase were observed. Our findings demonstrate for the first time the anti-proliferative action of L-783,277 on the human adrenocortical H295R cell line.

Growth hormone-releasing hormone stimulates the secretion of interleukin 17 from human peripheral blood mononuclear cells in vitro

OBJECTIVES

Growth hormone-releasing hormone (GHRH) plays a crucial role in the secretion of GH from the pituitary, acts as a growth factor in variety of cancer cells and possesses immunomodulatory activity. Interleukin(IL)-17 apart from its pro-inflammatory role has been also shown to play a role in carcinogenesis. The effect of GHRH on the IL-17 has not been studied so far.

AIM

To evaluate the effect of GHRH on the secretion of IL-17 from human peripheral blood mononuclear cells (PBMC) in vitro.

MATERIALS AND METHODS

The concentrations of IL-17 in supernatants from PBMC cultured for 24 hrs were assessed using ELISA kit.

RESULTS

We show for the first time that GHRH can stimulate the secretion of IL-17 from human PBMC in 24 hrs culture, and that GHRH antagonist counteracts this effect.

CONCLUSION

Our study further elucidates the immunomodulatory role of GHRH.

Stimulatory effect of growth hormone-releasing hormone (GHRH(1-29)NH2) on the proliferation, VEGF and chromogranin A secretion by human neuroendocrine tumor cell line NCI-H727 in vitro

Growth hormone-releasing hormone (GHRH) and its receptors have been implicated in a variety of cellular processes like cell survival, proliferation, apoptosis, angiogenesis and neoplastic transformation of various non-pituitary tissues. Here, we investigated for the first time the in vitro effect of GHRH(1-29)NH2 on the proliferation and the secretion of vascular endothelial growth factor (VEGF) and chromogranin A by the human bronchial neuroendocrine tumor cells NCI-H727. GHRH(1-29)NH2 at the concentrations of 10(-8)-10(-6)M increased the proliferation of these cells and this effect was associated with a statistically significant increase in VEGF and chromogranin A secretion into the supernatants of the tested cells. Our findings indicate that GHRH functions as a trophic hormone for bronchial neuroendocrine (NET) tumors.

Peripheral blood concentrations of vascular endothelial growth factor and its soluble receptors (R1 and R2) in patients with adrenal cortex tumours treated by surgery

INTRODUCTION

Neoangiogenesis appears to be an important event in tumour invasion and in the formation of metastases in many endocrine-related human cancers. Vascular endothelial growth factor (VEGF) is a glycoprotein with potent angiogenic, mitogenic and vascular permeability-enhancing activities specific for endothelial cells and acts through VEGF receptors. The aim of the study was to evaluate the plasma blood concentrations of VEGF, sVEGFR1, and sVEGFR2 in patients with benign and malignant adrenal tumours treated by surgery.

MATERIAL AND METHODS

We studied the blood before surgery of 41 patients with adrenal cortex tumours and 10 normal subjects without hormonal or CT/USG pathology of the adrenal glands (controls). We studied the blood after adrenalectomy of 16 patients with tumours of the adrenal cortex.

RESULTS

Concentrations of VEGF, sVEGFR1 and sVEGFR2 in blood plasma before as well as 30 days after surgery were evaluated by ELISA. VEGF blood concentrations before surgery did not differ in the patients with the cortical tumours as compared to the controls. After surgery VEGF concentrations decreased among the patients, taken in total, with adrenal cortex tumours and cortical adenomas. Before surgery sVEGFR1 blood concentrations were increased in the patients with Conn's syndrome only in comparison with the controls. After surgery, sVEGFR1 concentrations decreased significantly in the group with cortical adenomas only. Before and after surgery sVEGFR2 blood concentrations did not differ between the groups of patients studied and the controls.

CONCLUSIONS

Peripheral blood concentrations of VEGF and its receptors cannot be clinically valuable markers that discriminate between benign and malignant adrenocortical tumours before and after adrenalectomy.

Luzindole but not 4-phenyl-2- propionamidotetralin (4P-PDOT) diminishes the inhibitory effect of melatonin on murine Colon 38 cancer growth in vitro

OBJECTIVE

Our earlier studies have shown that MLT exerts the inhibitory effect on murine cancer via membrane and nuclear receptors. We have found that the antagonist of MT1 receptors does not diminish the antiproliferative effect of MLT on Colon 38 cells, and the contribution of MT2 receptors has been suggested to be responsible. Therefore, in the present study we have examined the influence of the 4-phenyl-2-propionamidotetralin (4P-PDOT), which is a selective antagonist of MT2 membrane receptor, and luzindole - an antagonist of both membrane receptors, on an oncostatic action of MLT.

MATERIALS AND METHODS

The murine cancer cell line Colon 38 was used in the experiments. In 48 hrs cell culture the effects of MLT, 4P-PDOT and luzindole administered alone and MLT applied jointly with either 4P-PDOT or luzindole were examined. The growth of cancer cells was assessed using the modified colorimetric Mosmann method.

RESULTS

Melatonin at both examined concentrations (10-7, 10-9 M) significantly decreased the viability of cancer cells. The selective antagonist of MT2 membrane receptor, namely 4P-PDOT and luzindole applied separately did not have an effect on the growth of Colon 38 cells. The addition of 4P-PDOT to MLT did not change the inhibitory effect of MLT, whereas luzindole given together with MLT diminished, but failed to block totally, the oncostatic properties of MLT.

CONCLUSIONS

The obtained data and our previous studies conducted on Colon 38 cancer indicate that membrane melatonin receptors are not indispensable to the oncostatic action of melatonin and thus other pathways such as nuclear signaling and receptor-independent mechanism may be also involved.

The place of somatostatin analogs in the diagnosis and treatment of the neuoroendocrine glands tumors

Somatostatin (SS) was originally discovered as a hypothalamic neurohormone which inhibits growth hormone secretion. The synthesis of the first two metabolically stabilized and more potent SS analogs, octreotide and lanreotide leads to the establishment of applications for them and to introduction into routine therapies. The effectiveness of octreotide or lanreotide in controlling symptoms and GH/IGF-I hypersecretion in acromegalic patients, both preoperatively and postoperatively is well proven. Similarly, these drugs are also very effective in the treatment of TSH-secreting adenomas. The introduction of these drugs into therapy of the functional neuroendocrine tumors of the gastrointestinal tract was a crucial step in the treatment. Octreotide and lanreotide are the drugs of choice in the treatment of patients with: VIPoma, glucagonoma and carcinoid syndrome. Somatostatin receptor scintigraphy with OctreoScan has been recommended as the best imaging technique in these tumors in the localization and staging procedure. SS analogs, coupled to radioisotope or cytotoxic drugs, create another class of SS molecules, very promising in the therapy of the endocrine glands tumors and in other tumors. Another class of SS analogs comprises hybrid molecules, which are chimera of sst2 agonist and D2 agonist, possessing more potent activity than these agonists, applied together.

Angiotensin peptides regulate angiogenic activity in rat anterior pituitary tumour cell cultures

INTRODUCTION

Angiogenesis has been shown to be necessary for the development and progression of solid tumours. VEGF is one of the crucial pro-angiogenic cytokines produced by the cells of many of the tumours examined, including various types of anterior pituitary adenomas. Angiotensin II (Ang II) is known to regulate the expression of VEGF in a variety of tissues both in the physiological and pathological conditions. Moreover, an association of the renin-angiotensin system (RAS) with oestrogen-induced vascular changes during the development of rat pituitary PRL-secreting adenoma has already been demonstrated. The aim of the study was to determine the in vitro effects of angiotensin peptides (Ang II, Ang III and Ang IV) on the secretion of VEGF in two anterior pituitary adenoma cell cultures: the culture of the rat pituitary lactosomatotrope tumour cell line (GH3) and the primary culture of rat PRL-secreting tumour induced by diethylstilbestrol (DES).

MATERIAL AND METHODS

GH3 and prolactinoma cells were cultured in an F10 and an F-12 medium respectively and then placed into 24 multiwell plates (10(5) of GH3 cells/well and 10(6) of rat prolactinoma cells/well). After 12 hours of preincubation the cells underwent 24-hour treatment with Ang II, Ang III or Ang IV at final concentrations of 10(-12), 10(-10), 10(-8) or 10(-6)M and, in the case of the GH3 cells, combined treatment with Ang II (10(-10)M) and specific AT1 or AT2 receptor antagonist (losartan or PD123319 respectively at a concentration of 10(-8) or 10(-7) M). The concentration of VEGF in the supernatant collected was determined using specific ELISA assay kits. Statistical evaluation was performed using Student's test and analysis of variance (ANOVA). Differences were considered significant if p < 0.05.

RESULTS

The incubation of both GH3 cells and rat adenoma cells with Ang II, Ang III or Ang IV at concentrations of 10(-12) -10(-8)M resulted in a significant increase in VEGF concentration in the culture medium. Exposure of GH3 cells to Ang III or Ang IV at concentrations of 10(-6)M led to a significant inhibition of cytokine release, and Pearson's correlation curve showed a tendency for Ang II at concentrations of more than 10(-6)M to inhibit VEGF secretion in primary prolactinoma cell culture. The stimulatory influence of Ang II on VEGF secretion in GH3 cell culture was negated by losartan or by PD123319 in both concentrations tested.

CONCLUSIONS

Ang II, Ang III and Ang IV affect the secretion of VEGF in cultures of the rat lactosomatotrope GH3 cell line and primary rat prolactinoma cells. Both AT1 and AT2 receptors mediate the stimulatory action of Ang II on the cytokine release in GH3 cell culture. The mechanism of the observed anti-angiogenic effects of angiotensin peptides remains unexplained.

Oestradiol and tamoxifen inhibit murine Colon 38 cancer growth and increase the cytotoxic effect of fluorouracil

The poor efficacy of reference chemotherapy (fluorouracil -FU) in colon cancer has resulted in a constant search for agents which could augment the action of FU. Epidemiological data, such as the decreased risk of colorectal cancer among menopausal women receiving hormonal replacement therapy, indicate the role of oestrogen in the pathogenesis of this disease. The differences between normal and neoplastic colon cells in the expression of oestrogen receptor beta (ERbeta) could confirm this association. However, the direct influence of oestrogen or tamoxifen (SERM, selective oestrogen receptor modulator) on colon cancer growth has rarely been studied. The aim of the present study was to examine the direct effects of various concentrations of oestradiol and tamoxifen (10(-4) to 10(-12) M), applied alone or together with FU, on the growth of murine Colon 38 cancer in vitro as assessed by three colorimetric methods: Mosmann's method, incorporation of BrdU into cell nuclei and the TUNEL method. At high concentrations oestradiol and tamoxifen decreased the cancer growth in a dose- and time-dependent manner (the Mosmann and BrdU methods) and at some concentrations augmented the cytotoxic action of FU (Mosmann's method). Tamoxifen exerted a very early and potent inhibitory effect, inducing even total cancer growth inhibition at the concentration of 10(-4) M (the Mosmann and BrdU methods). All the substances studied at different concentrations and at different incubation time points increased the apoptosis of tumour cells (the TUNEL method). The results indicate that oestradiol and tamoxifen inhibit Colon 38 cancer growth and increase the cytotoxic effect of FU, which confirms the role of sex steroids in colon carcinogenesis and even suggests new therapeutic schemes.

[Anti-cytokine and anti-lymphocyte monoclonal antibodies in the treatment of thyroid associated ophthalmopathy]

Graves' ophthalmopathy or thyroid associated ophthalmopathy (TAO) is an autoimmune disease of the orbit involving both the retroorbital connective tissue and the extraocular muscles, but its pathogenesis is still incompletely understood. Examination of retroorbital tissues in the initial inflammatory phase of TAO reveals an accumulation of hydrophilic glycosaminoglycans, increased fat volume, marked T and B lymphocytic infiltration, and presence of many pro-inflammatory cytokines and growth factors. Peripheral blood levels of pro-inflammatory cytokines released from T and B lymphocytes (IFN-gamma, IL-1beta, IL-2, slL-2R TNF-alpha, IL-6, IL-6R) and antibodies of TSH receptor (TRAb) secreted from B lymphocytes are markers of the immune system activity. Updated the efficacy of the new anti-cytokine and anti-lymphocyte treatment of the Graves' ophthalmopathy has been revived. We described the first positive results of anti-B lymphocyte (anti-CD20; rituximab) and anti-TNF-alpha monoclonal antibodies (infliximab; etanercept) administration as new therapeutic options in the treatment of patients with active TAO. A randomized prospective study are needed to determine whether rituximab, infliximab or etanercept prove sufficiently effective in reducing the inflammatory symptoms of TAO, and whether they can be administered safely for a prolonged period without side effects.

Effects of somatostatin-14 and the receptor-specific somatostatin analogs on chromogranin A and alpha-subunit (alpha-SU) release from "clinically nonfunctioning" pituitary adenoma cells incubated in vitro

The aim of the study was to examine the effect of somatostatin (SST) and its analogs on the release of chromogranin A (CgA) and alpha-subunit (alpha-SU) from clinically non-functioning pituitary adenomas incubated in vitro. Seven pituitary macroadenomas surgically removed were investigated. All of the tumors were diagnosed before surgery as non-functioning, but they expressed either gonadotropins or their subunits as detected by immunohistochemistry. Two tumors additionally expressed prolactin and growth hormone. All adenomas also expressed chromogranin A (CgA) and at least 3 of 5 subtypes of somatostatin receptors. The cells isolated from the examined tumors were exposed in vitro to either native SST-14 or the following receptor-specific SST analogs: BIM-23926 (agonist of sst1 receptor), BIM-23120 (agonist of sst2 receptor), BIM-23206 (agonist of sst5 receptor) and BIM23A387 (somatostatin/dopamine chimera). The concentration of CgA was measured by means of ELISA method and of alpha-SU was measured by an immunoradiometric method. It was found that the exposure on SST-14 resulted in the decrease of CgA and alpha-SU release from tumor cells in majority of samples, and the effect on CgA was positively correlated with the expression of sst3 and also with the sst2A/sst2B expressions ratio. The inhibitory effect of SST-14 on CgA and alpha-SU seems also to correlate negatively with the expression of sst2B. CgA inhibition also correlates positively with sst5 expression. Among the other compounds studied, only the sst2 agonist decreased the release in all the investigated samples. The remaining substances (agonists of sst1 and sst5 and SST/DA chimera) produced the divergent changes (increased or decreased release, depending on the sample). The data suggest that the inhibition of CgA (and possibly of alpha-SU) release by SST is mediated via subtypes sst2A, sst3 and sst5, whereas sst2B subtype may induce the opposite effect.

Leptin promotes the growth of Colon 38 cancer cells and interferes with the cytotoxic effect of fluorouracil in vitro

INTRODUCTION

Epidemiological studies underline the fact that obesity represents a significant risk factor for the development of several cancers, one of which is cancer of the colon. Moreover, multiple recent data indicate that some adipose tissue-derived hormones may influence the growth of malignant cells. Leptin, the product of the ob gene, is one of these. However, the evidence from research is still contradictory regarding the role of leptin in colon cancer. The aim of our study was to examine the direct effect of leptin at various concentrations (from 10(-5) to 10(-12) M) when applied alone or jointly with fluorouracil (the classical cytotoxic drug for colon cancer) at two concentrations (0.25 mg/ml and 2.5 mg/ml) on the growth of murine Colon 38 cancer cells in vitro.

MATERIAL AND METHODS

Colon 38 cancer cells were preincubated in RPMI 1640 medium supplemented with foetal calf serum for 24 hours. The cells were then cultured for a further 72 hours in the presence of various concentrations of the substances under examination, applied either alone or jointly. The growth of the Colon 38 cell line was assessed by a colorimetric kit based on the modified Mosmann method.

RESULTS

We found that leptin increased the growth of murine Colon 38 cancer at concentrations of 10(-6), 10(-7) M and 10(-10), 10(-11), 10(-12) M. Its stimulatory effect was fairly slight, with an increase in cancer growth of 5% to 15% as compared to controls. As we expected, fluorouracil at both the concentrations examined inhibited the growth of Colon 38 cancer maximally up to 28% (2.5 mg/ml) and 34% (0.25 mg/ml) of controls, with a stronger effect obtained from higher doses. Leptin did not modulate the cytotoxic effect of fluorouracil applied at the higher concentration (2.5 mg/ml) but, unexpectedly, at concentrations of 1(-9) and 10(-10) M it heightened the cytotoxic effect of fluorouracil given at a lower concentration (0.25 mg/ml).

CONCLUSIONS

These data indicate that leptin is involved in the regulation of colon cancer growth and it may even heighten the cytotoxic effect of fluorouracil.

Monoclonal anti-TNFalpha antibody (infliximab) in the treatment of patient with thyroid associated ophthalmopathy

TNFalpha (tumor necrosis factor alpha) plays a central role in the development of thyroid associated ophthalmopathy (TAO). We describe and document by ophthalmic (CAS and NO SPECS scales) and radiological (MRI) evaluation a positive effect of anti-TNFalpha antibody (infliximab) administration on active TAO in a 58 years old woman with Graves' disease. The single dose of infliximab administration resulted in a dramatic reduction of inflammation studies and improvement of visual function as measured by MRI and CAS and NO SPECS scales, without noticeable short-term side effects. A randomized prospective study is needed to determine whether infliximab proves to be sufficiently effective in reducing the inflammatory symptoms of TAO, and whether it can be administered safely for a prolonged period without side effects.

Inhibitory effect of thalidomide on the growth, secretory function and angiogenesis of estrogen-induced prolactinoma in Fischer 344 rats

The process of angiogenesis has been found to be essential for the development of estrogen-induced pituitary prolactinoma in Fischer 344 rats. Thalidomide [(alpha-(N-phthalimido)-glutarimide] is known to be a potent immunomodulatory drug with antiangiogenic properties, but its effect on lactotroph cell secretory function and pituitary prolactinoma formation has not been described yet. The purpose of this study was to examine the effects of thalidomide on secretion of prolactin (PRL) and vascular endothelial growth factor (VEGF), cell proliferation, apoptosis and angiogenesis within the anterior pituitary gland in long-term diethylstilboestrol (DES)-treated male F344 rats in vivo and in vitro. It was found that DES sharply increased serum PRL and VEGF levels. On the other hand, simultaneous treatment of F344 rats with thalidomide for the last 15 days of the experiment attenuated the stimulatory effect of DES on PRL and VEGF secretion. It also diminished prolactin cell proliferation evaluated as the number of proliferating cell nuclear antigen (PCNA)-positive stained cell nuclei and increased the number of apoptotic bodies determined by the terminal deoxynucleotidyl-mediated dUTP nick-end labeling (TUNEL) method in sections of the DES-induced pituitary prolactinoma. The density of pituitary microvessels evaluated by microscopic counting of CD-31-positive blood vessels was also diminished by the tested drug. In addition, thalidomide (10(-4) to 10(-6) M) inhibited cell proliferation, prolactin and VEGF secretion from rat pituitary prolactinoma cells cultured in vitro. In conclusion, our results provide strong evidence for the antiprolactin and antitumor activity of thalidomide in experimentally DES-induced pituitary adenoma.

Growth-inhibitory action of melatonin and thiazolidinedione derivative CGP 52608 on murine 16/C breast cancer cells

OBJECTIVES

Melatonin may influence directly tumor cells through the specific binding sites. The best known melatonin binding sites are membrane receptors. Recently, the participation of nuclear signalling via estrogen as well as RZR/ROR receptors in oncostatic action of melatonin on the breast cancer has been widely discussed. The aim of present study was to investigate effects of melatonin, the selective ligand for nuclear RZR/ROR receptors - CGP 52608, and methotrexate on growth of murine 16/C breast cancer cells.

MATERIAL AND METHODS

The experiment was performed in vitro. The breast cancer cells were incubated for 2 days in the presence of melatonin, CGP 52608 (at concentrations of 10(-5)M, 10(-7)M, 10(-9)M, 10-(11)M ) and methotrexate (at concentrations of 0.25 and 0.125 microg/ml). The growth of cells was measured using the modified Mossman method.

RESULTS

All examined compounds significantly inhibited the growth of cancer cells. The effects of MLT and CGP 52 608 were comparable with suppression caused by methotrexate. The significant differences of efficacy between two examined concentrations of methotrexate were not observed.

CONCLUSION

The obtained data together with our previous results indicate that nuclear receptors RZR/ROR play an important, although not sufficiently recognized role in the oncostatic action of melatonin.

Effect of the growth hormone-releasing hormone [GHRH(1-44)NH2] on IL-6 and IL-8 secretion from human peripheral blood mononuclear cells in vitro

OBJECTIVE

Bidirectional communication between the neuroendocrine and immune systems is now a subject of an intensive investigation. Growth hormone-releasing hormone (GHRH) is synthesized by the hypothalamus, but is present also in the immune cells. Some recent data indicate also an immunomodulatory role of the neuropeptide. The aim of the study was to examine the influence of GHRH(1-44)NH2 on interleukin-6 and interleukin-8 secretion from human peripheral blood mononuclear cells cultured in vitro.

METHODS

Peripheral blood mononuclear cells (PBMC) were isolated by centrifugation using Böyum technique and cultured in a humidified atmosphere of 5 % CO2 and 95 % O2 at 37 degrees C for 24 hours in the presence of lipopolysaccharide (LPS) at the concentration of 2 microg/ml and GHRH(1-44)NH2 (the final neuropeptide concentrations to be tested were 10(-12) to 10(-6) M). ELISA methods were used to measure IL-6 and IL-8 concentrations in the supernatants of cultured cells

RESULTS

GHRH(1-44)NH2 influenced IL-6 secretion from cultured cells, but significant inhibition of IL-6 release was observed at 10-6 M (p < 0.001). The negative correlation between the GHRH concentration studied and the IL-6 level in the supernatants was found (r = -0.759; p < 0.001). GHRH had no influence on the secretion of IL-8 from activated PBMC.

CONCLUSIONS

Our results demonstrate that GHRH in vitro modulates IL-6 secretion from the human peripheral blood mononuclear cells, without any significant effect on IL-8 secretion.

Melatonin inhibits growth of diethylstilbestrol-induced prolactin-secreting pituitary tumor in vitro: possible involvement of nuclear RZR/ROR receptors

Melatonin exerts a marked antiproliferative action in numerous experimentally-induced tumors in vivo as well as in both animal and human cell lines in vitro. However, the mechanisms of oncostatic action of melatonin is not clear, and the involvement of both membrane and nuclear receptors are suggested. Therefore, the aim of this study was to investigate effects of melatonin, and both agonist (CGP 52608), and antagonist (CGP 55644) of RZR/ROR nuclear receptors on the growth of diethylstilbestrol-induced rat prolactin-secreting pituitary tumor cells in vitro. Pituitary tumors were induced by subcutaneous implantation of a single silastic capsule containing 10 mg of diethylstilbestrol in 4-wk-old male Fischer 344 rats. Four months after the implantation of capsules the animals were killed by decapitation, pituitary tumors were aseptically removed, mechanically dispersed, and enzymatically digested with 0.2% collagenase and 0.2% hyaluronidase. The cells (6 x 105 cells/well) were incubated for 24 hr in the presence of melatonin, CGP 52608, CGP 55644 and CGP 55644 plus melatonin (at the concentrations of 107 and 10-9 m) at 37 degrees C in the humidified atmosphere of 95% air and 5% CO2. The group with the addition of solvent only served as control. The growth of cell was measured using the EZ4U system. Statistical analysis was performed using ANOVA followed by LSD test. Both melatonin and CGP 52608 significantly suppressed growth of tumor cells in vitro in both used concentrations. CGP 55644 stimulated growth of tumor cells and blocked the inhibitory effects of melatonin in vitro. Results of the present study as well as other experimental evidence strongly support the hypothesis that both membrane and nuclear receptors are involved in the oncostatic action of melatonin, and indicate that nuclear signalling plays an important role in this process.

Effects of melatonin and melatonin receptors ligand N-[(4-methoxy-1H-indol-2-yl)methyl]propanamide on murine Colon 38 cancer growth in vitro and in vivo

OBJECTIVES

Our previous study suggest that oncostatic action of melatonin (MLT) depends mainly on nuclear RZR/ROR receptors. However, we cannot exclude the involvement of membrane receptors in the control of tumor growth. In the present study the effects of MLT and N-[(4-methoxy-1H-indol-2-yl)methyl]propanamide (UCM 386 - antagonist of membrane MT(1) receptor and partial agonist of membrane MT(2) receptor) on murine transplantable Colon 38 cancer were investigated in vitro and in vivo conditions.

MATERIAL AND METHODS

The experiments were performed on adult male B6D2F1 mice strain. In vitro the cell proliferation was measured using modified Mosmann method. In the experiment performed in vivo, we assessed the cell proliferation, apoptosis and proliferation/apoptosis ratio (P/A). The incorporation of bromodeoxyuridine into tumor cell nuclei was used as an index of cell proliferation (labeling index-LI). The labeling of apoptotic cells according to TUNEL method was considered as an index of apoptosis (AI).

RESULTS

In vitro MLT and UCM 386 decreased the cell proliferation, but administration of MLT and UCM 386 together did not change the inhibitory effect of MLT alone. In vivo MLT and UCM 386 alone decreased LI and the addition of UCM 386 to MLT did not diminish the antiproliferative effect of MLT. Melatonin and UCM 386 injected alone also increased the AI. Moreover, both compounds given together exerted the additive effect on tumor apoptosis. MLT and UCM 386 alone or together also significantly decreased P/A ratio which is additional parameter confirming the inhibition of tumor growth.

CONCLUSION

The obtained data together with our earlier observations suggest that oncostatic effect of MLT depends on acting via both MT(2) and RZR/ROR nuclear receptors

Effect of somatostatin and octreotide on proliferation and vascular endothelial growth factor secretion from murine endothelial cell line (HECa10) culture

Angiogenesis, development of new blood vessels, is required for normal tissue repair and also for tumor cell proliferation, extracellular matrix invasion, and hematogenous metastases. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen that has been shown to play a key role in neovascularization. Inhibition of angiogenesis in vitro and in vivo was documented by administration of native neuropeptide somatostatin and its analog octreotide. We have studied the effect of somatostatin-14 (SRIF) and ocreotide (sandostatin) on proliferation activity and VEGF release from cultured murine endothelial cells HECa10 in vitro. SRIF in concentrations from 10(-9) to 10(-5) M and ocreotide in concentrations from 10(-9) to 10(-5) M diminished the proliferative activity of cultured cells vs controls. SRIF and ocreotide in concentrations from 10(-14) to 10(-6) M did not change the release of VEGF into supernatants of 24 or 72 h endothelial cell cultures. Although we showed the antiproliferative effect of SRIF and ocreotide on mouse endothelial cells, we were unable to demonstrate the inhibitory effect of tested peptides on VEGF secretion in vitro.