Immunohistochemical detection of dopamine D2 receptors in human pituitary adenomas.

Thirty one pituitary adenomas and 3 samples of peritumoral anterior pituitary tissue were immunostained with an antibody raised against dopamine D2 receptor protein. The positive reactions were found in cell cytoplasm, a subpopulation of cell nuclei and the intratumoral blood vessels walls. As expected, the positive immunostaining was shown in cytoplasm and/or cell nuclei of all examined prolactinomas (7/7). In acromegaly the positive D2 staining occurred in 5/7 samples, in gonadotropinomas in 6/8 and in plurihormonal adenomas 2/4. The lowest expression was observed in corticotropinomas (1/5). These findings corroborate with the well known efficacy of D2 agonists in the treatment of prolactinomas and somatotropinomas, and support the rationale of the therapeutic trials with these compounds in gonadotropinomas. Moreover, the presence of D2 receptors in intratumoral blood vessels walls constitutes the possibility of the anti-angiogenic action of D2 agonists in pituitary adenomas

Circular dichroism study of the light-harvesting PCP complexes within the vibronic multistate dimer theory

Chiral properties of peridinin-chlorophyll-protein (PCP) light-harvesting complexes are studied in terms of vibronic dimer theory previously applied to study certain structural aspects of α-crustacyanin pigments. On the base of CD spectra it is shown that the peridinin dimer acts as a chiral group in PCP complexes and its geometrical structure is such that the peridinin monomers cannot be coplanar. Certain observations concerning the energy transfer process in PCP complexes in vivo are also made

Immunohistochemical detection of prothymosin alpha in pituitary adenomas--a new marker of tumor recurrence?

Forty pituitary adenomas were immunostained with an antibody raised against the C-terminal fragment (101-109) of human prothymosin alpha (PT alpha). The strong positive immunostaining was found in the subpopulation of cell nuclei and intratumoral vessel walls, while the cytoplasm of adenoma cells was slightly immunopositive. The significantly higher percentage of PT alpha-positive cell nuclei was found in recurrent pituitary adenomas as compared with primary tumors. However, there was no correlation between the percentage of PT alpha-positive cell nuclei and Ki-67 indices. Gonadotropinomas were characterized by higher nuclear PT alpha expression in comparison to other pituitary adenomas, which is probably linked with the high recurrence rate of these tumors. It is suggested that PT alpha immunostaining may be helpful in predicting the pituitary tumor recurrence. However, this conclusion needs to be confirmed in further prospective studies. Moreover, PT alpha may be also useful as an immunohistochemical marker of the intratumoral microvasculature

Immunohistochemical detection of PPARγ receptors in the human pituitary adenomas: correlation with PCNA

The occurrence of peroxisome proliferator-activated receptors gamma (PPARγ) was investigated in 51 human pituitary adenomas and in 6 non-tumoral human pituitary tissue samples. Moreover, the correlation between PPARγ and the proliferating cells nuclear antigen (PCNA) - immunocytochemical proliferation marker was evaluated. The receptors and PCNA were detected by immunohistochemical methods using the polyclonal anti-PPARγ and the monoclonal anti-PCNA antibodies, respectively. PPARγ were found in all examined tissues. The mean percentage of cells with positive nuclear reaction was 3-fold higher in pituitary adenomas in comparison with non-tumoral pituitary tissues. The strongest expression of PPARγ was observed in somatotropinomas. Besides the nuclear reaction, which is typical for PPARγ, positive immunostaining was also observed in the cytoplasm. It was clearly stronger in pituitary adenomas than in non-tumoral pituitary tissues. A slight, statistically insignificant tendency towards negative correlation between PPARγ and PCNA was found in somatotropinomas, prolactinomas, corticotropinomas and gonadotropinomas. On the other hand, in null cell adenomas and "silent" corticotropinomas, a strong positve correlation between the expression of PPARγ and PCNA was observed. The strong expression of PPARγ in human pituitary adenomas and its possible involvement in control of cell proliferation in these tumors give a good reason for the attempts of their treatment with PPARγ ligands

The incidence of somatostatin receptors in human neoplasms in the light of ex vivo–in vitro studies

Human neoplastic cells express and often even over-express the somatostatin receptors (sstr). It concerns not only pituitary tumors and the so-called neuroendocrine tumors of the gut, but many other neoplasms, including the non-endocrine cancers. The incidence of sstr is important because it determinates the possibility of treatment with SST (somatostatin) analogs. The examination of sstr is possible under the in vivo conditions, by means of the receptor scintigraphy using the radiolabeled SST analogs. The receptors can be also examined under the ex vivo–in vitro conditions, using the post-surgical or biopsy specimens. Among the in vitro (ex vivo) methods, the immunohistochemical investigation with specific anti-receptor antibodies seems to be particularly useful for routine clinical diagnostics. This review presents the data, obtained by means of different in vitro techniques, on the incidence of five sstr subtypes in the different human tumors, deriving from endocrine glands, diffuse neuroendocrine cells as well as in neoplasms consididered as non-endocrine.W komórkach ludzkich nowotworów często ma miejsce ekspresja, a nawet nadekspresja receptorów somatostatynowych (sstr, somatostatin receptor). Dotyczy to nie tylko guzów przysadki oraz tak zwanych guzów neuroendokrynnych przewodu pokarmowego, ale także wielu innych nowotworów, w tym także nieendokrynnych. Występowanie sstr ma istotne znaczenie, ponieważ warunkuje możliwość ich leczenia analogami somatostatyny. Badanie sstr jest możliwe w warunkach in vivo, dzięki zastosowaniu scyntygrafii receptorowej ze znakowanymi radionuklidami analogami somatostatyny (SST, somatostatin). Omawiane receptory mogą być także badane ex vivo–in vitro z użyciem materiału operacyjnego lub biopsyjnego. Szczególną użyteczność dla praktyki klinicznej spośród badań in vitro ma metoda immunohistochemiczna, z użyciem swoistych przeciwciał przeciwko białkom receptorowym. W pracy omówiono, na podstawie przeprowadzonych różnymi technikami badań ex vivo–in vitro, występowanie 5 znanych podtypów sstr w różnych ludzkich nowotworach, zarówno wywodzących się z gruczołów dokrewnych i rozproszonych komórek neuroendokrynnych, jak i uważanych za nieendokrynne

Immunohistochemiczna detekcja receptorów dopaminowych D2 w guzach neuroendokrynnych

Background: Recently, dopamine D2 receptors (RD2) have been found to be expressed in neuroendocrine tumours (NET), the tumours which arise from the diffuse neuroendocrine cells. Moreover, successful trials of the treatment of NET with cabergoline — D2 agonist, have been reported. These findings increase the interest of investigating RD2 expression in NET. Material and methods: The expression of RD2 was investigated immunohistochemically using the antibody which recognises both short (S) and long (L) isoforms of the receptor in 17 NET samples taken from 15 patients. Results: In 17 NET samples, a positive reaction with the anti-RD2 antibody occurred in 11 cases. In six cases, the localisation of the immunostaining was cytoplasmic and in nine cases it was nuclear. Only in one case was the receptor cell membrane-located, and in two cases the immunoreaction was also localised in the blood vessels walls. The relation between RD2 expression and the grade of malignancy examined by means of Ki-67 antigen expression needs further study. However, preliminary observations indicate that the nuclear localisation of RD2 is linked to higher tumour malignancy. The next investigated question was the co-expression of somatostatin and dopamine receptors. This question seems important because of the perspectives of somatostatin-dopamine chimeras application in NET treatment. In the samples examined by us, RD2 were co-expressed in 5/10 cases with sstr1, in 3/10 with sstr2A, in 2/9 with sstr2B, in 3/10 with sstr3, and in 5/10 with sstr5. Conclusion: Dopamine D2 receptors are revealed by means of immunohistochemistry in the majority of NET. They exhibit cytoplasmic and/or nuclear localisations, the latter being possibly linked to a higher grade of malignancy, and are often co-expressed with somatostatin receptors (mostly with subtypes1 and 5). (Pol J Endocrinol 2011; 62 (5): 388–391)Wstęp: Ostatnio wykryto występowanie receptorów dopaminowych D2 (RD2) w guzach neuroendokrynnych (NET) i doniesiono o skutecznych próbach leczenia NET kabergoliną — agonistą tych receptorów. Zwiększa to znaczenie badań nad ekspresją RD2 w NET. Materiał i metody: Zbadano 17 wycinków guzów NET pobranych od 15 pacjentów. Badania immunohistochemiczne przeprowadzono z użyciem przeciwciała rozpoznającego zarówno krótką (S), jak i długą (L) izoformę receptora D2. Wyniki: Pozytywny odczyn z przeciwciałem anty-RD2 występował w 11 spośród 17 badanych przypadków NET. W 6 na 17 badanych wycinków był to odczyn o lokalizacji cytoplazmatycznej, w 9 na 17 odczyn jądrowy, a tylko w jednym przypadku odczyn o lokalizacji błonowej. Ponadto w 2 przypadkach obserwowano odczyn w ścianach naczyń krwionośnych. Podjęto próbę oceny zależności między stopniem złośliwości guza, określonym na podstawie badania antygenu Ki-67, a ekspresją RD2. Wstępne obserwacje wskazują, że lokalizacja jądrowa odczynu na RD2 wiąże się z wyższym stopniem złośliwości nowotworu. Zależność ta wymaga dalszych badań na większym materiale. Ponadto zbadano współwystępowanie receptorów somatostatynowych i dopaminowych. Zagadnienie to ma istotne znaczenie ze względu na perspektywy stosowania chimer somatostatynowo-dopaminowych w leczeniu NET. W badanych przez autorów pracy guzach cytoplazmatyczne receptory D2 występowały w 5 spośród 10 przypadków, łącznie z sstr1, w 3/10 z sstr2A, w 2/9 z sstr 2B, 3/10 z sstr3 i 5/10 z sstr5. Wnioski: Receptory dopaminowe D2 wykrywa się za pomocą metody immunohistochemicznej w większości NET. Mają one lokalizację cytoplazmatyczną i/lub jądrową. Lokalizacja jądrowa wydaje się wiązać z większym stopniem złośliwości nowotworu. RD2 wykazują często koekspresję z receptorami somatostatynowymi, zwłaszcza podtypami 1 i 5.(Endokrynol Pol 2011; 62 (5): 388–391

Immunohistochemical detection of angiotensin receptors AT1 and AT2 in adrenal tumors.

Angiotensin II is well known to affect the adrenal cell growth and function. Angiotensin receptors AT1 and AT2 were found to be present in the normal adrenal gland. However, the data on the expression of the angiotensin receptors in the adrenal tumors are very scarce. To overcome this gap, the paraffin sections of the adrenal cortical tumors and of pheochromocytomas from the archival material were immunostained with antibodies raised against AT1 (sc-1173) and AT2 (sc-9040) receptor proteins. In hyperplasia of the adrenal cortex and in benign adrenocortical adenomas, both functioning and non-functioning, the AT1 immunostaining was present mainly in the cell membranes. A positive immunoreaction was also found in the subpopulation of cell nuclei and within the cytoplasm. In the adrenal cancer, as well as in pheochromocytomas, neither cell membranes nor cell nuclei were immunostained with anti-AT1 antibody. However, a weak AT1 immunostaining was present within the cytoplasm of tumoral cells. With anti-AT2 antibody, in all tumors investigated, the tumoral cells were immunonegative but moderate to strong AT2 immunostaining was observed in the walls of intratumoral blood vessels and in the interstitial tissue. Our data indicates that the expression of AT1 receptors is altered in adrenal cancer and in pheochromocytomas. The expression of AT2 receptors, in turn, may be connected with the process of tumoral neo-angiogenesis

Immunohistochemical demonstration of LH/CG receptors in non-neoplastic human adrenal cortex and adrenocortical tumors

Introduction. Numerous data indicate that luteinizing hormone and/or chorionic gonadotropin (LH/CG) exert direct actions on the adrenal cortex and are involved in the adrenal pathology. However, the immunohistochemical studies on the expression of LH/CG receptors (LH/CGR) in the human adrenal cortex and in the adrenocortical tumors are scarce. Material and methods. Paraffin sections of samples of 6 human non-neoplastic adrenal cortex and 25 adrenocortical tumors were immunostained with anti-LH/CGR polyclonal antibody. Results. All zones of the human non-neoplastic adrenal cortex present a positive immunoreaction with anti-LH/CGR antibody showing the strongest reaction in cell membranes. The LH/CGR immunostaining in the vast majority of hormonally non-functioning adenomas and in all hormone-secreting adenomas does not differ from the non-neoplastic adrenal cortex. In contrast to non-neoplastic adrenal cortex and benign adenomas, in adrenocortical cancers the immunostaining with anti-LH/CGR antibody behaves differently. The immunopositive material is almost totally filling the cytoplasm of the cells but the immunopositivity of cell membranes is weak or lacking. Conclusions. The data presented in our study show that the expression of LH/CGR in adrenocortical tumors is not ectopic but eutopic. The immunohistochemical examination of LH/CGR may be useful in the differentiation between benign and malignant lesions in the adrenal cortex. Moreover, the loss of membrane localization of LH/CGR in adrenocortical cancer suggests the alteration of receptors’ function.

Immunohistochemical detection of follicle stimulating hormone receptor (FSHR) in neuroendocrine tumours

Wstęp: Wiadomo, że ekspresja receptorów folitropiny (FSHR) występuje w gonadach i wywodzących się z gonad nowotworach. Ostatniowykazano ich obecność także w innych nowotworach endokrynnych, takich jak guzy nadnerczy i gruczolaki przysadki. Ponadtostwierdzono immunopozytywność dla FSHR w śródbłonkach około- i wewnątrzguzowych naczyń krwionośnych różnych nowotworówzłośliwych. W obecnej pracy wykazano obecność FSHR zarówno w komórkach nowotworowych, jak i niektórych wewnątrz-guzowychnaczyniach krwionośnych guzów neuroendokrynnych (NETs).Materiał i metody: Zbadano 16 wycinków pobranych od 14 pacjentów z NETs. Odczyny immunohistochemiczne wykonano z użyciemprzeciwciała skierowanego przeciw fragmentowi 1-190 ludzkiego FSHR oraz przeciwciała dla Ki-67.Wyniki: Dodatni odczyn z przeciwciałem anty-FSHR stwierdzono w cytoplazmie większości komórek badanych guzów. W połowie badanychNETs odnotowano także immunopozytywność dla FSHR w śródbłonkach wewnątrzguzowych naczyń krwionośnych. Dodatniodczyn dla FSHR obserwowano częściej w naczyniach krwionośnych nowotworów z wyższym indeksem Ki-67.Wnioski: Ektopowe FSHR, jeśli są one aktywne, mogą przekazywać sygnały nasilające dalszy wzrost NETs.(Endokrynol Pol 2013; 64 (4): 268–271)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 immunostaininghas also been reported in endothelium of intra- and peritumoral blood vessels of a large series of cancers. The presentpaper 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 antibodyraised 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 immunostainingconcerned also the intratumoral blood vessels endothelia in a half of the examined samples. Immunopositive blood vessels were foundmore often in tumours with higher Ki-67 index.Conclusion: FSHR expressed in NETs, if they are functional, may mediate the signals which can enhance further tumour growth

The effect of octreotide and bromocriptine on expression of a pro-apoptotic Bax protein in rat prolactinoma.

It is well established that disruption of apoptosis may lead to tumor initiation, progression or metastasis. It is also well documented that many anticancer drugs induce apoptosis. In the earlier studies, the dopamine D2 receptor agonist bromocriptine (BC) and somatostatin analog octreotide (OCT) were found to inhibit the growth of the estrogen-induced rat prolactinoma. Our previous investigations, applying the TUNEL method showed the involvement of the pro-apoptotic effect in the action of BC, and to a lesser degree, in the action of OCT. The aim of the present study was to investigate whether the pro-apoptotic action of these drugs involves the increased expression of Bax--a member of Bcl-2 protein family which is known to play an important role in the regulation of apoptosis. Male four-week Fisher 344 rats were used in the experiment. Capsules containing diethylstilboestrol (DES) were implanted subcutaneously. Six weeks after the implantation the rats were given OCT (2 x 25 microg/animal/24), BC (3 mg/kg b.w./24 h) or OCT and BC at the above doses for 10 days. Bax expression was detected by immunohistochemistry. Prolactin (PRL) in blood serum was measured by radioimmunoassay (RIA). It has been found that both OCT and BC, alone or in combination, significantly reduce the tumor weight. Both OCT and BC suppressed PRL levels, but the inhibitory effect of BC was stronger than that of OCT. It has been found that the treatment with OCT and BC, alone or in combination, causes a significant increase in Bax expression in the rat prolactinoma cells. Our findings indicate that anti-tumoral action of bromocriptine and to some extent the action of octreotide in the experimental rat prolactinoma is connected with the induction of apoptosis and is associated with increased Bax expression