Gabriela Mełeń-Mucha

The inhibitory effect of diarylpropionitrile, a selective agonist of estrogen receptor beta, on the growth of MC38 colon cancer line

The protective role of estrogens in the colon carcinogenesis has been suggested for many years and attributed mainly to estrogen receptor beta (ERbeta). However, the direct effect of estrogens and their action through ERbeta on the growth of colon cancer have been rarely studied. The aim of this study was to examine the effect of various concentrations (10(-4)-10(-12)M) of diarylpropionitrile (DPN)--a selective agonist of ERbeta--on the growth of murine MC38 colon cancer line. Moreover, the aim of this paper was the immunohistochemical assessment of estrogen and progesterone receptor expression in human colon tissues and in MC38 cells (only ERbeta). We found that DPN induced a growth inhibition of MC38 cancer (50-94% of control group) at the highest (10(-4)M) and two lowest concentrations (10(-11) and 10(-12)M). Furthermore, we detected a nuclear-cytoplasmic expression of ERbeta in human normal and neoplastic colon tissues and in the studied MC38 cancer cells. The inhibitory effect of DPN on the growth of MC38 colon cancer line suggests a possibility of using a selective estrogen receptor agonist in the treatment of colon cancer.

The involvement of the renin-angiotensin system in the regulation of cell proliferation in the rat endometrium

Abstract. Oestrogens are known to enhance angiotensin biosynthesis by increasing the elaboration of its precursor, angiotensinogen. On the other hand, we found that inhibition of angiotensin-converting enzyme (ACE) suppressed the proliferative response of the rat anterior pituitary gland to oestrogens. To answer the question whether the angiotensin system is involved in the control of the cell proliferation of the uterine epithelium, the effects of an ACE inhibitor, enalapril maleate, and of angiotensins II and IV, alone or together with losartan, an antagonist of angiotensin receptor type 1 (AT1), on endometrial epithelial cell proliferation have been studied. The experiments were performed on ovariectomized female Wistar rats. In the first experiment the animals were injected with a single dose of oestradiol benzoate or received an injection of solvent only. Half of the oestrogen-treated rats were injected additionally with enalapril maleate (EN, twice daily). The incorporation of bromodeoxyuridine (BrDU) into endometrial cell nuclei was used as an index of cell proliferation. It was found that oestradiol alone dramatically increased the BrDU labelling index (LI) of endometrial cell nuclei, and this effect was partially blocked by the simultaneous treatment with EN. In the second experiment, the animals were injected intraperitoneally with angiotensin II (AII), angiotensin IV (AIV) or saline, alone or together with losartan. It was found that AIV induced an increase in the LI in uterine epithelium, and this effect was not blocked by the simultaneous treatment with losartan. The increase in LI in uterine epithelium was also observed in the rats treated with AII and with losartan. These findings suggest an involvement of angiotensin IV in the control of uterine epithelium cell proliferation.

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.

Neuroendocrine neoplasms of the small intestine and the appendix — management guidelines (recommended by the Polish Network of Neuroendocrine Tumours)

We present revised Polish guidelines regarding the management of patients harbouring neuroendocrine neoplasms (NENs) of the small intestine and appendix. The small intestine, especially the ileum, is the most common origin of these neoplasms. Most of them are well differentiated with slow growth. Rarely, they are less differentiated, growing fast with a poor prognosis. Since symptoms can be atypical, the diagnosis is often accidental. Typical symptoms of carcinoid syndrome occur in less than 10% of patients. The most useful laboratory marker is chromogranin A; 5-hydroxyindoleacetic acid is helpful in the monitoring of carcinoid syndrome. Ultrasound, computed tomography, magnetic resonance imaging, colonoscopy, video capsule endoscopy, balloon enteroscopy and somatostatin receptors scintigraphy are used in the visualisation. A histological report is crucial for the proper diagnostics and therapy of NENs, and it has been extensively described. The treatment of choice is surgery, either radical or palliative. Somatostatin analogues are crucial in the pharmacological treatment of the hormonally active and non-active small intestine NENs and NENs of the appendix. Radioisotope therapy is possible in patients with a good expression of somatostatin receptors. Chemotherapy is not effective in general. Everolimus therapy can be applied in patients with generalised NENs of the small intestine in progression and where there has been a failure or an inability to use other treatment options. Finally, we make recommendations regarding the monitoring of patients with NENs of the small intestine and appendix.

Diagnostic and therapeutic guidelines for gastro-entero-pancreatic neuroendocrine neoplasms (recommended by the Polish Network of Neuroendocrine Tumours)

An increased interest in gastro-entero-pancreatic neuroendocrine neoplasms (GEP NENs) has recently been observed. These are rare neoplasms and their detection in recent years has improved. Over 50% of GEP NENs are carcinoids, and they are usually found incidentally during surgery in the small intestine and appendix and at diagnosis in distant metastases, mainly to the liver. There is a need for co-operation between specialists in various disciplines of medicine in order to work out the diagnostic and therapeutic guidelines. In this publication, we present general recommendations of the Polish Network of Neuroendocrine Tumours for the management of patients with GEP NENs, developed at the Consensus Conference which took place in Kamień Śląski in April 2013. Members of the guidelines working groups were assigned sections of the 2008 guidance to update. In the subsequent parts of this publication, we present the rules of diagnostic and therapeutic management of: - neuroendocrine neoplasms of the stomach and duodenum (including gastrinoma); - pancreatic neuroendocrine neoplasms; - neuroendocrine neoplasms of the small intestine and the appendix; - colorectal neuroendocrine neoplasms. The proposed recommendations by Polish and foreign experts representing different fields of medicine (endocrinology, gastroenterology, surgery, oncology, nuclear medicine and pathology) will be helpful in the diagnosis and treatment of GEP NENs patients.

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.

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.

Estrone and progesterone inhibit the growth of murine MC38 colon cancer line.

The unsatisfactory effectiveness of reference chemotherapy in colon cancer (fluorouracil - FU) results in continuous search for agents, which could enhance the action of FU. Some epidemiological data such as a decreased risk of colorectal cancer among menopausal women receiving hormonal replacement therapy indicate the role of female sex hormones in the pathogenesis of this disease. The aim of this study was to examine the direct effects of various concentrations of estrone and progesterone (10(-4) to 10(-12)M) applied alone or together with FU on the growth of murine MC38 colon cancer in vitro. Estrone inhibited MC38 cancer growth in a wide range of concentrations (10(-12) to 10(-4)M) with similar potency and at some concentrations (10(-6) and 10(-4)M) augmented also the cytotoxic action of FU. Progesterone induced MC38 cancer growth inhibition at high concentrations (10(-5) to 10(-4)M) in dose- and time-dependent manner but it did not intensify antineoplastic effect of FU. A weak inhibitory effect of progesterone was also observed for lower concentrations (10(-5) to 10(-10)M) in long lasting cultures (72h). The results indicate that estrone and progesterone inhibit the MC38 cancer growth and that estrone increases also the cytotoxic effect of FU, what confirms the role of female sex steroids in modulation of colon cancer growth.

Pancreatic neuroendocrine neoplasms — management guidelines (recommended by the Polish Network of Neuroendocrine Tumours)

We present revised diagnostic and therapeutic guidelines for the management of pancreatic neuroendocrine neoplasms (PNENs) proposed by the Polish Network of Neuroendocrine Tumours.These guidelines refer to biochemical (determination of specific and nonspecific neuroendocrine markers) and imaging diagnostics (EUS, CT, MR, and radioisotope examination with a 68Ga or 99Tc labelled somatostatin analogue).A histopathological diagnostic, which determines the further management of patients with PNENs, must be necessarily confirmed by immunohistochemical tests. PNENs therapy requires collaboration between a multidisciplinary team of specialists experienced in the management of these neoplasms. Surgery is the basic form of treatment. Medical therapy requires a multidirectional procedure, and therefore the rules of biotherapy, peptide receptor radionuclide therapy, chemotherapy and molecular targeted therapy are discussed.

Elevated Peripheral Blood Plasma Concentrations of Tie-2 and Angiopoietin 2 in Patients with Neuroendocrine Tumors

Background Gastro-entero-pancreatic/neuroendocrine (NET) tumors are highly vascularized neoplasms. However, our knowledge concerning circulating levels of the angiogenic factors in NET patients still remains insufficient. Methods The aim of this study was to measure plasma concentrations of VEGF, angiopoietin 1 (Ang-1), angiopoietin 2 (Ang-2), soluble Tie-2, endostatin, osteopontin (OPN) and chromogranin A (CgA) in 36 NET patients and 16 controls. Results Only the plasma concentrations of Tie-2 and CgA were higher in NET patients as compared to controls. These levels were within the reference range in controls; however one control demonstrated slightly elevated Tie-2 and 4 elevated CgA. Similarly, in the subgroup of patients with carcinoid syndrome, only Tie-2 and CgA concentrations were higher than those in patients with non-functioning NETs. In turn, in the subgroup of metastatic patients, only Ang-2 levels were higher than in those with localized disease. A positive correlation was found between Ang-2 and Tie-2 levels in metastatic patients and between Ang-1 and Tie-2 in localized NETs. Conclusions The plasma concentration of Tie-2 is proposed as an additional marker for NET patients and seems to be similarly effective as the currently used CgA level. Moreover, higher plasma levels of Ang-2 together with the positive correlation between Ang-2 and Tie-2 levels in metastatic subjects, implies that cases with a Tie-2 level above the upper limits, together with higher level of Ang-2 seem to be highly predictive of metastases.