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 role of peroxisome proliferators-activated receptors (PPARγ) in neoplasms of endocrine glands

The peroxisome proliferators-activated receptors gamma (PPAR) belong to the family of nuclear receptors, which directly regulate transcription of target genes. PPARγ take part in many processes such as adipogenesis, glucose and lipid metabolism, atherosclerosis and inflammation and carcinogenesis. The expression of PPARγ was detected in normal and tumor cells of endocrine glands. Activation of receptors by specific ligands of PPARγ induces inhibition of cell proliferation, induction of apoptosis and terminal differentiation as well as inhibition of angiogenesis. In the present paper the structure, tissue expression and biological function of PPARγ are presented. The reports about oncostatic effects of PPARγ agonists in pituitary adenomas, thyroid cancers and adrenal tumor are reviewed. (Pol J Endocrinol 2008; 59 (2): 156-166)Receptory aktywowane proliferatorami peroksysomów gamma (PPARγ) należą do rodziny receptorów jądrowych regulujących transkrypcję docelowych genów. Receptory aktywowane proliferatorami peroksysomów gamma biorą udział w wielu procesach, takich jak: adipogeneza, metabolizm glukozy i lipidów, zapalenia, miażdżyca i karcinogeneza. Ekspresję PPARγ wykazano w prawidłowych i zmienionych nowotworowo gruczołach dokrewnych. Aktywacja receptorów poprzez swoiste ligandy powoduje obniżenie proliferacji, nasilenie apoptozy i prawidłowe różnicowanie komórek nowotworowych oraz hamuje angiogenezę. W pracy omówiono budowę, lokalizację tkankową i właściwości PPARγ oraz przedstawiono dotychczasowe doniesienia na temat działania agonistów PPARγ na gruczolaki przysadki, nowotwory tarczycy i guzy nadnerczy. (Endokrynol Pol 2008; 59 (2): 156-166

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

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

Endocrine and metabolic aspects of COVID-19

The paper presents the theoretical considerations on the role of endocrine and metabolic alterations accompanying COVID-19 infection. These alterations may be presumed on the basis of the following two observations. Firstly, the virus SARS-CoV-2 responsible for the COVID-19 infection uses an important renin–angiotensin system (RAS) element — angiotensin-converting enzyme 2 (ACE2) — as a receptor protein for entry into target cells and, in consequence, disturbs the function of the main (circulating) renin–angiotensin–aldosterone system (RAAS) and of the local renin–angiotensin system localized in different tissues and organs. The binding of SARS-CoV-2 to ACE2 leads to the downregulation of this enzyme and, in the aftermath, to the excess of angiotensin II and aldosterone. Thus, in the later stageof COVID-19 infection, the beneficial effects of ACEI and ARB could be presumed. It is hypothesized that the local RAS dysregulation in the adipose tissue is the main cause of the negative role of obesity as a risk factor of severe outcome of the COVID-19 infection. Secondly, the outcome of COVID-19 strongly depends on the age of the patient. Age-related hormonal deficiencies, especially those of melatonin and dehydroepiandrosterone, may contribute to morbidity/mortality in older people. The usefulness of melatonin and angiotensin converting enzyme inhibitors/angiotensin receptor 1 blockers (the latter only in later phases of the infection) as adjuvant drugs is probable but needs thorough clinical trials.

Expression of α-Klotho protein in human thyroid cancers — an immunohistochemical study

Introduction: The α-Klotho protein was discovered as a gene controlling the process of aging, but further studies indicated that it also plays the role of a tumour suppressor. Although numerous studies were performed on the role of the α-Klotho gene and protein in neoplasia, the data on α-Klotho protein expression in thyroid cancers are very scarce. Our study presents the immunohistochemical investigation of α-Klotho expression in benign and malignant thyroid tumours. Material and methods: The material included samples of benign (nodular hyperplasia, follicular adenoma), differentiated (follicular and papillary) cancers and aggressive thyroid cancers of low differentiation grade. The samples were immunostained using two different monoclonal anti-α-Klotho antibodies. Results: From the two antibodies used in this study, one (EPR6856) reacted probably with the soluble form of Klotho and immunostained mostly the colloid filling thyroid follicles and intravascular or extravascular serum deposits. The other (A-9 antibody) immunostained the follicular epithelium in benign thyroid lesions as well as the epithelial tumoural cells in differentiated thyroid (follicular and papillary cancers). In the thyroid cancers of high malignancy, the immunostaining with A-9 anti-α-Klotho antibody was (except in one case) negative or very weak. Conclusion: Our results indicate that lowered expression of a- Klotho is involved in the process of thyroid neoplasia

Does the response of GH-secreting pituitary adenomas to octreotide depend on the cellular localization of the somatostatin receptor subtypes SSTR2 and SSTR5?

Wstęp: Badania immunohistochemicze ekspresji podtypów receptora somatostatynowego (SSTR1-5, somatostatin receptor 1-5) w guzach endokrynnych wykazują ich obecność zarówno w błonie komórkowej, jak i na terenie cytoplazmy komórek guza. Szeroko stosowany obecnie syntetyczny analog somatostatyny - oktreotyd wykazuje powinowactwo głównie do podtypów SSTR2 i SSTR5. W naszych wcześniejszych badaniach zauważono pozytywną korelację między zsumowanym wskaźnikiem (score) nasilenia odczynu immunohistochemicznego SSTR2A i 2B, a hamowaniem sekrecji hormonu wzrostu (GH, growth hormone) po podaniu oktreotydu u chorych z akromegalią, niezależnie od lokalizacji receptorów w komórkach guza. Obecne badania autorów pracy dotyczą ewentualnej współzależności pomiędzy hamowaniem GH w odpowiedzi na oktreotyd a komórkową lokalizacją SSTR2A, 2B i 5. Materiał i metody: Zbadano 13 chorych z akromegalią, u których przed operacją wykonano krótki test z oktreotydem. W gruczolakach przysadki określono immunohistochemicznie ich fenotyp hormonalny oraz występowanie i lokalizację podtypów SSTR. Wyniki: W większości przypadków obserwowano cytoplazmatyczną ekspresję badanych podtypów SSTR, aczkolwiek występowała również lokalizacja błonowa i mieszana błonowo-cytoplazmatyczna. Spadek wydzielenia GH w teście hamowania oktreotydem zawierał się w przedziale pomiędzy 57,1-96,7% (średnio 82,1%). Największy znamienny spadek wydzielenia GH (92,0 ± 7,0%) po podaniu oktreotydu wystąpił u pacjentów z cytoplazmatyczną lokalizacją SSTR5 w komórkach guza. Zauważono także tendencję do silniejszej odpowiedzi u pacjentów, u których również SSTR2A i 2B miały położenie cytoplazmatyczne (odpowiednio 86,8% i 87,0%). Wnioski: Wydaje się, że cytoplazmatyczne, a nie błonowe położenie SSTR2A, 2B i 5, jest powiązane z silniejszym hamowaniem GH w teście z oktreotydem. Możliwe, że oktreotyd w procesie internalizacji receptora zmienia jego położenie z błonowego na cytoplazmatyczne i zwiększa jego immunopozytywność w cytoplazmie badanych komórek guza. (Endokrynol Pol 2010; 61 (2): 178-181)Introduction: The immunohistochemical examination of somatostatin receptor (SSTR) subtypes expression in different endocrine tumours, including pituitary adenomas, revealed membranous or cytoplasmic distribution of SSTR1-5. Currently used long-acting somatostatin analogue octreotide prefers SSTR2 and SSTR5 subtypes. In an earlier study a positive correlation between the summarized score of SSTR2A + SSTR2B expressions and growth hormone (GH) response to octreotide administration was found, independently of receptor distribution within the cell. In this study we searched for the relationship between the GH inhibitory response to acute octreotide administration and SSTR2A, SSTR2B, and SSTR5 cellular localization. Material and methods: Thirteen acromegalic patients underwent a test of acute administration of octreotide before surgery. The drop in GH was defined as the percentage of the basal value. The pituitary adenomas from these patients were immunostained to determine the hormonal phenotype and expression of SSTR subtypes. The subcellular distribution pattern of SSTR subtypes - membranous or cytoplasmic - was determined. Results: In the majority of specimens, cytoplasmic localization of receptor subtypes was observed, although membrane or mixed cytoplasmicmembranous localized immunopositivity also occurred. The drop in GH after octreotide administration varied between 57.1-96.7% (mean 82.1%). Among the patients with the cytoplasmic localization of SSTR5, the decrease in GH was significantly higher (92.0 ± 7.0%). A tendency towards the higher response in patients with cytoplasmic localization of SSTR2A and 2B was also observed (86.8% and 87.0%, respectively). Conclusions: It seems that cytoplasmic localization of SSTR5, SSTR2A, and SSTR2B is connected with enhanced GH inhibition after octreotide administration. It is possible that this somatostatin analogue alters the localization of subtypes SSTR2A and SSTR2B through the receptor internalization. As a consequence, the SSTR-immunopositivity in cell cytoplasm is increased. The cytoplasmic but not the membranous localization is connected with the higher responsiveness to the octreotide in somatotropinomas. (Pol J Endocrinol 2010; 61 (2): 178-181

SSTR1 and SSTR5 subtypes are the dominant forms of somatostatin receptor in neuroendocrine tumors.

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