Gonadotroph Pituitary Adenomas Research Articles

Characterization of Gonadotroph Pituitary Adenomas Based on the Recent 2017 WHO Pituitary Tumor Classification

Abstract Introduction: More than 20% of pituitary adenomas are nonfunctional, the majority of which are of gonadotroph origin. Whereas previously, immunohistochemistry of pituitary hormones was used to classify adenoma subtypes, in 2017 the World Health Organization (WHO) reclassified pituitary adenomas using transcription factor expression in addition to immunohistochemistry. With this change, clinically nonfunctional gonadotroph adenomas can be distinguished among: (1) those staining for the transcription factor SF-1 and gonadotropins FSH and/or LH (FSH/LH+), (2) those that stain for SF-1 but not for FSH or LH (FSH/LH- SF1+), and (3) true null cell adenomas. It is unclear whether these three subgroups behave similarly clinically, or if they have distinct manifestations or outcomes. Our aim was to characterize these subgroups in regard to tumor size, recurrence and pituitary insufficiency. Methods: In a retrospective chart review, 71 patients from 2017-2020 who presented to the hospital for transsphenoidal resection of clinically nonfunctioning pituitary adenomas were reviewed. All patients with pituitary adenomas that stained positive for SF-1 and negative for T-PIT and PIT-1, and tumors that were negative for all three transcription factors were evaluated. Those lacking clinical data were excluded. Clinical characteristics examined include: demographics, tumor size, invasion of cavernous sinus, and hormone deficiencies. Results: Of the 71 pituitary tumors, 45% (n=32) stained positive for the beta subunit FSH and/or LH (FSH/LH+) and SF-1, 44% (n=31) stained for SF-1 with negative pituitary hormone stains (FSH/LH- SF1+), and 11% (n=8) were negative for all transcription factors and hormones (true null). All tumors were macroadenomas (>1 cm). While there were >50% males in the FSH/LH+ and FSH/LH- SF1+ groups, in the true null group only 25% of patients were male. Most patients were >50 years old in all 3 groups (81% FSH/LH+, 75% FSH/LH- SF1+, 88% true null). The prevalence of cavernous sinus involvement was 36% in both groups that stained for SF-1, but was 62% in the true null group. Both SF-1+ groups had similar tumor sizes and prevalence of panhypopituitarism (15-21%), but there were more episodes of recurrence since last known follow up in the FSH/LH- SF1+ group (20%), compared to FSH/LH+ tumors (7%). The true null group had ≥50% rates for both panhypopituitarism and recurrence. Conclusions: In this study, we highlighted the category of FSH/LH- SF1+ gonadotroph adenomas and compared these to FSH/LH+ and true null cell tumors. Based on clinical features, FSH/LH- SF1+ gonadotroph adenomas are similar to FSH/LH+ staining pituitary adenomas in regard to age, sex, size, and degree of cavernous sinus invasion, although there were more recurrences in the FSH/LH- SF1+ group. Though less common, our cohort suggests more aggressive tendencies in the true null group compared to SF-1 staining tumors.

Magnetic resonance fingerprinting for preoperative differentiation between gonadotroph and non-gonadotroph pituitary macroadenomas.

To use magnetic resonance fingerprinting (MRF)-derived T1 and T2 values to differentiate gonadotroph from non-gonadotroph pituitary macroadenomas based on the 2017 World Health Organization classification of pituitary adenomas. A total of 57 patients with suspected pituitary macroadenomas were enrolled for analyses in this study between May 2018 and January 2020. Conventional magnetic resonance imaging (MRI) and MRF were performed in all patients before surgery using a 3-T MRI scanner. MRF-derived T1 and T2 values were compared between the gonadotroph and non-gonadotroph pituitary macroadenomas using a Mann-Whitney U test. The Knosp classification was used to evaluate cavernous sinus invasion by the adenomas. Receiver operating characteristic analyses were used to determine the diagnostic performance of T1 and T2 values. Quantitative T1 and T2 values yielded from MRF of gonadotroph pituitary macroadenomas were significantly higher than those of the non-gonadotroph pituitary macroadenomas (p < 0.001 and = 0.002, respectively). The AUC for the T2 value (0.888) was significantly greater than that for the T1 value (0.742) (p = 0.034). The AUC for combined T1 and T2 values was 0.885. Non-gonadotroph pituitary macroadenomas were more likely to invade the cavernous sinus than gonadotroph pituitary macroadenomas (55% vs 26%, p = 0.026). MRF may help to preoperatively differentiate between gonadotroph and non-gonadotroph pituitary macroadenomas and may be useful in guiding the treatment of these adenomas. • Somatostatin receptor type 3 is the most abundant receptor subtype in gonadotroph pituitary adenomas. • Magnetic resonance fingerprinting may help to preoperatively differentiate between gonadotroph and non-gonadotroph pituitary macroadenomas. • Magnetic resonance fingerprinting shows potential for guiding the treatment of pituitary macroadenomas.

SAT-269 A Rare Case of Functioning Gonadotroph Producing Pituitary Macroadenoma in Teenage Male

Background: Unlike nonfunctioning gonadotroph pituitary adenomas, functioning gonadotroph pituitary adenomas (FGA) are an uncommon type of pituitary tumors that secrete biologically active gonadotropins (LH, FSH, or both). Clinical Case: A 23-year-old man with no previous medical history presented to the emergency department with three months history of progressive decreased vision and decreased libido. He denied headache, seizure, erectile dysfunction, or weakness. On physical examination, his visual acuity was significantly reduced on the right eye and was only able to perceive light. He had a visual field narrowing on the left eye. Gynecomastia was noted bilaterally and testicles were found to be enlarged (Orchidometer >25 mL). Complete blood count was significant for hemoglobin of 19.2 g/dL (N, 13.7-17.5 g/dL), and hematocrit of 57.0% (N, 40.1-51.0%). Pituitary function tests were as follow: FSH >200.0 mIU/mL (N, 1.5-12.4 mIU/mL), LH 17.0 mIU/mL (N, 1.7-8.6 mIU/mL), total testosterone 41.3 nmol/L (N, 8.6-29.0 nmol/L), free testosterone 1.263 nmol/L (N, 0.148-0.718 nmol/L), and bioavailable testosterone 29.609 (N, 2.110-8.920 nmol/L). Prolactin, TSH, GH, and ACTH were all within the normal range. Magnetic resonance imaging (MRI) showed a sellar mass involving the planum sphenoidal measuring 5.8 x 5.2 x 5.6 cm with optic chiasm displaced superiorly, in addition, subfalcine herniation with mild hydrocephalus was also noted. The patient underwent orbitozygomatic approach resection of the pituitary tumor. Histological examination was consistent with a pituitary adenoma. Cells stained positive for transcription factor steroidogenic factor 1 (SF 1), FSH, LH, and alpha-subunit consistent with a gonadotroph adenoma. They were negative for transcription factor Pit 1 stain and the remaining pituitary hormones including ACTH, GH, prolactin, and TSH stain. Postsurgical hormone assessment showed a significant decline in FSH and LH to 2.3 and 0.4 mIU/mL, respectively and testosterone level decreased to < 0.087 nmol/L on postoperative day 18. The patient’s vision improved postoperatively prior to discharge but he lost follow up thereafter. Conclusion: Most patients with functioning gonadotroph pituitary adenoma present with large tumors that are detected based on the occurrence of symptoms of compression that result from the enlarging sellar mass. Most patients, particularly men and postmenopausal women, do not develop symptoms of hormone excess and the lack of symptomatology results in delay in diagnosis. Our patients presented with significant polycythemia which resulted from excess testosterone and could have prompted earlier tumor detection if he had presented in an earlier stage. The incidence of polycythemia in male patients with functioning gonadotroph pituitary adenoma has previously been described in the literature in a few case reports.

Lineage-dependent role of miR-410-3p as oncomiR in gonadotroph and corticotroph pituitary adenomas or tumor suppressor miR in somatotroph adenomas via MAPK, PTEN/AKT, and STAT3 signaling pathways

PurposemiR-410-3p plays opposite roles in different cancers and may act as an oncomiR or tumor suppressor miR. The purpose of this study was to assess the role of miR-410-3p in somatotroph, gonadotroph, and corticotroph pituitary adenomas.MethodsTissue samples were obtained from 75 patients with pituitary adenoma. miR-410-3p expression was assessed using qRT-PCR performed on RNA isolated from fresh frozen samples. In vitro experiments were performed on cell lines derived from somatotroph (GH3), gonadotroph (RC-4B/C), and corticotroph (AtT-20) pituitary tumors. Cells were transfected with synthetic mimic of miR-410-3p or non-targeting scrambled-miR control. Subsequently, proliferation assays and transwell invasion assays were performed. The expression of cyclin D1, E1, and B1 in cells after transfection was determined using qRT-PCR. The activation of MAPK, PTEN/AKT and STAT3 signaling pathways were assessed using western blot.ResultsWe have found that the level of expression of miR-410-3p differs in particular types of pituitary adenomas. miR-410-3p significantly upregulates proliferation and invasiveness of RC-4B/C and AtT-20 cells, while inhibiting GH3 cells. We observed that the levels of cyclin B1 upon transfection with miR-410-3p mimic were increased in RC-4B/C and AtT-20, yet decreased in GH3 cells. We have shown that miR-410-3p promoted the activation of MAPK, PTEN/AKT, and STAT3 signaling pathways in RC-4B/C and AtT-20 cells, but suppressed their activity in GH3 cells.ConclusionsmiR-410-3p acts as an oncomiR in gonadotroph and corticotroph adenoma cells, while as a tumor suppressor miR in somatotroph adenoma cells.

RPSAP52 lncRNA is overexpressed in pituitary tumors and promotes cell proliferation by acting as miRNA sponge for HMGA proteins.

Long non-coding RNAs (lncRNAs) are emerging as fundamental players in cancer biology. Indeed, they are deregulated in several neoplasias and have been associated with cancer progression, tumor recurrence, and resistance to treatment, thus representing potential biomarkers for cancer diagnosis, prognosis, and therapy. In this study, we aimed to identify lncRNAs associated with pituitary tumorigenesis. We have analyzed the lncRNA expression profile of a panel of gonadotroph pituitary adenomas in comparison with normal pituitaries. Then, we focused on RPSAP52, a novel lncRNA antisense for the HMGA2 gene, whose overexpression plays a critical role in the development of pituitary adenomas. We report that RPSAP52 expression is highly upregulated in gonadotroph and prolactin-secreting pituitary adenomas, where it correlates with that of HMGA2, compared with normal pituitary tissues. Conversely, its expression showed a variable behavior in somatotroph adenomas. We also demonstrate that RPSAP52 enhances HMGA2 protein expression in a ceRNA-dependent way acting as sponge for miR-15a, miR-15b, and miR-16, which have been already described to be able to target HMGA2. Interestingly, RPSAP52 also positively modulates HMGA1, the other member of the High-Mobility Group A family. Moreover, functional studies indicate that RPSAP52 promotes cell growth by enhancing the G1-S transition of the cell cycle. The results reported here reveal a novel mechanism, based on the overexpression of the lncRNA RPSAP52, which contributes to pituitary tumorigenesis, and propose this lncRNA as a novel player in the development of these tumors. KEY MESSAGES: RPSAP52 is overexpressed in pituitary adenomas. RPSAP52 increases HMGA protein levels. A ceRNA mechanism is proposed for the increased HMGA1/2 expression.

Attenuation of MAMLD1 Expression Suppresses the Growth and Migratory Properties of Gonadotroph Pituitary Adenomas.

Gonadotroph pituitary adenomas (GPAs) constitute approximately 15-40% of pituitary tumors. Some GPAs can be highly infiltrative, making full surgical resection challenging and increasing the risk of recurrence. The transcriptional co-activator Mastermind-Like Domain Containing 1 (MAMLD1, CXorf6, F18) is involved in regulating signaling pathways important in pituitary tumorigenesis, including the Notch signaling pathway. However, MAMLD1's role in GPA remains unknown. GPA biopsies were collected from 96 patients following surgery, who were monitored until tumor recurrence. GPA tissue was used for immunohistochemistry. The murine GPA cell lines αT3 and LβT2 were used for in vitro experiments. Lentiviral constructs were employed for MAMLD1 knockdown (KD) and dominant negative (DN) mutant experiments. Quantitative real-time PCR (qPCR) and Western blotting of MAMLD1 and Notch2 were performed. MTT and Transwell assays were used to quantify proliferation and migration, respectively. An αT3 xenograft model was established in athymic nude mice followed by fluorescent IHC of xenograft tumors. MAMLD1 and Notch2 levels correlated positively with aggressive GPAs. Increased MAMLD1 levels correlated with shortened recurrence-free survival (RFS) in aggressive GPA patients. Moreover, MAMLD1 expression independently affected patient RFS according to multivariate Cox regression. In vitro, MAMLD1 KD in the murine GPA cell lines attenuated their proliferation and migration and Notch2 expression. Additionally, DN MAMLD1L210X lowered their proliferative and migratory capacity. MAMLD1 KD suppressed tumor growth and Notch2 expression in murine xenografts. MAMLD1 may serve as a predictor of GPA patient outcome and may also be leveraged as a possible therapeutic target for aggressive GPA tumors.

Gene expression profiling of fast- and slow-growing non-functioning gonadotroph pituitary adenomas.

Reliable biomarkers associated with aggressiveness of non-functioning gonadotroph adenomas (GAs) are lacking. As the growth of tumor remnants is highly variable, molecular markers for growth potential prediction are necessary. We hypothesized that fast- and slow-growing GAs present different gene expression profiles and reliable biomarkers for tumor growth potential could be identified, focusing on the specific role of epithelial-mesenchymal transition (EMT). Eight GAs selected for RNA sequencing were equally divided into fast- and slow-growing group by the tumor volume doubling time (TVDT) median (27.75 months). Data were analyzed by tophat2, cufflinks and cummeRbund pipeline. 40 genes were selected for RT-qPCR validation in 20 GAs based on significance, fold-change and pathway analyses. The effect of silencing MTDH (metadherin) and EMCN (endomucin) on in vitro migration of human adenoma cells was evaluated. 350 genes were significantly differentially expressed (282 genes upregulated and 68 downregulated in the fast group, P-adjusted <0.05). Among 40 selected genes, 11 showed associations with TVDT (-0.669<R<-0.46, P < 0.05). These were PCDH18, UNC5D, EMCN, MYO1B, GPM6A and six EMT-related genes (SPAG9, SKIL, MTDH, HOOK1, CNOT6L and PRKACB). MTDH, but not EMCN, demonstrated involvement in cell migration and association with EMT markers. Fast- and slow-growing GAs present different gene expression profiles, and genes related to EMT have higher expression in fast-growing tumors. In addition to MTDH, identified as an important contributor to aggressiveness, the other genes might represent markers for tumor growth potential and possible targets for drug therapy.

Ovarian Hyperstimulation Caused by Gonadotroph Pituitary Adenoma--Review.

Ovarian hyperstimulation syndrome (OHSS) occurs mostly as an iatrogenic complication of assisted reproductive technology. Gonadotroph pituitary adenomas are rarely associated with OHSS. To the authors' knowledge, to date only 30 cases of spontaneous ovarian stimulation associated with gonadotroph adenomas have been reported in women and only 2 in children. The most common symptoms in such cases included menstrual disturbances, abdominal or pelvic pain, abdominal distension and increased girth. Galactorrhea, nausea and vomiting were also reported. Neurological symptoms occurred when the size of the pituitary tumor reached at least 20 mm. Transvaginal ultrasound examination usually demonstrated enlarged multicystic ovaries. MRIs of the pituitary revealed macroadenomas up to 61 mm in maximum diameter. The hormonal profiles of the reported cases showed normal or elevated FSH levels, suppressed LH levels, elevated estradiol levels and supranormal concentrations of prolactin. Transsphenoidal surgery is the therapy of choice, however other treatment modalities can be utilized in selected cases.

SSTR3 is a putative target for the medical treatment of gonadotroph adenomas of the pituitary.

Gonadotroph pituitary adenomas (GPAs) often present as invasive macroadenomas not amenable to complete surgical resection. Radiotherapy is the only post-operative option for patients with large invasive or recurrent lesions. No medical treatment is available for these patients. The somatostatin analogs (SSAs) octreotide and lanreotide that preferentially target somatostatin receptor type 2 (SSTR2) have little effect on GPAs. It is widely accepted that the expression of specific SSTR subtypes determines the response to SSAs. Given that previous studies on mRNA and protein expression of SSTRs in GPAs have generated conflicting results, we investigated the expression of SSTR2, SSTR3, and SSTR5 (the main targets of available SSAs) in a clinically and pathologically well-characterized cohort of 108 patients with GPAs. A total of 118 samples were examined by immunohistochemistry using validated and specific MABs. Matched primary and recurrent tissues were available for ten patients. The results obtained were validated in an independent cohort of 27 GPAs. We observed that SSTR3 was significantly more abundant than SSTR2 (P<0.0001) in GPAs, while full-length SSTR5 was only expressed in few tumors. Expression of SSTR3 was similar in primary and recurrent adenomas, was high in potentially aggressive lesions, and did not change significantly in adenomas that recurred after irradiation. In conclusion, low levels of expression of SSTR2 may account for the limited response of GPAs to octreotide and lanreotide. Given the potent anti-proliferative, pro-apoptotic, and anti-angiogenic activities of SSTR3, targeting this receptor with a multireceptor ligand SSA such as pasireotide may be indicated for potentially aggressive GPAs.

In vitro secretion of FSH by cultured clinically nonfunctioning and gonadotroph pituitary adenomas is directly correlated with locally produced levels of activin A

Expression of mRNAs encoding activin and its antagonists inhibin and follistatin has been described in human pituitary adenomas, including clinically nonfunctioning adenomas (NFAs) and gonadotroph adenomas (Gn-omas). Since many of the NFAs and Gn-omas secrete FSH in vitro, we hypothesized that locally produced activin may stimulate secretion of FSH in these pituitary adenomas. Pituitary adenoma tissue was obtained from 38 patients diagnosed preoperatively as having NFAs (n = 17), Gn-omas (n = 5), prolactinomas (n = 6) or growth hormone (GH)-producing adenomas (n = 10). Actual protein levels of activin, inhibin, follistatin, FSH and LH were measured in media of these 38 cultured pituitary adenomas. In addition, we investigated correlations between concentrations of these growth factors and hormones in NFAs and Gn-omas. Gn-omas were found to secrete significantly more activin A in their culture medium than PRL- and GH-producing adenomas (P < 0.05). Inhibin A and inhibin B protein levels in culture media were very low. A positive correlation between levels of activin A and FSH (r = 0.56, P < 0.005) was found, while no correlation between activin A and LH could be detected. Furthermore, levels of follistatin were positively correlated with activin A levels (r = 0.73, P < 0.0005). Comparison of the activin A:follistatin ratio with the measured FSH protein levels showed an even stronger relationship (r = 0.79, P < 0.0005). It is concluded that levels of activin A, follistatin and FSH in media of cultured nonfunctioning adenomas and gonadotroph adenomas are positively correlated. This suggests that these adenomas secrete FSH in response to the relatively high locally produced levels of activin A.

Interferon-alpha-2a is a potent inhibitor of hormone secretion by cultured human pituitary adenomas.

Interferon-alpha (IFN alpha) may exert direct inhibitory effects on cell proliferation and on the production of different peptide hormones. We investigated the effect of IFN alpha on hormone production by 15 GH-secreting pituitary adenomas, 4 clinically nonfunctioning or gonadotroph pituitary adenomas, and 4 prolactinomas in vitro. In the GH-secreting pituitary adenoma cultures, a short term (72-h) incubation with IFN alpha (50-100 U/mL) significantly inhibited GH secretion in 3 of 7 cases and PRL secretion in 6 of 7 cultures. During prolonged incubation (14 days) with IFN alpha, GH and/or PRL secretion was significantly inhibited in 7 of 8 cultures (GH, 17-78% inhibition; PRL, 39-88% inhibition). In the clinically nonfunctioning or gonadotroph cultures, incubation with IFN alpha resulted in inhibition of the secretion of gonadotropins and/or alpha-subunit in all cases (27-62%), whereas in the prolactinoma cultures PRL secretion was inhibited by IFN alpha in all cases (37-76%). The effect of IFN alpha was additive to the inhibitory effects of the dopamine agonist bromocriptine (10 nmol/L) or the somatostatin analog octreotide (10 nmol/L). The inhibition of hormone secretion by IFN alpha was accompanied by inhibition of the intracellular hormone concentrations. The effect of IFN alpha was dose dependent, with an IC50 for inhibition of hormone secretion of 2.3 +/- 0.3 U/mL (n = 5), which is relatively low compared with the concentrations that are reached in patients treated with IFN alpha for various malignancies. In conclusion, the potent antihormonal effect of IFN alpha on cultured pituitary adenomas suggests that this drug might be of benefit in the treatment of selected patients with secreting pituitary adenomas. As treatment with IFN alpha is associated with considerable adverse reactions, studies with this drug should only be considered in inoperable, invasive aggressive, and dopamine agonist- and/or somatostatin analog-resistant functioning pituitary macroadenomas.

A comparison between the diagnostic value of gonadotropins, alpha- subunit, and chromogranin-A and their response to thyrotropin-releasing hormone in clinically nonfunctioning, alpha-subunit-secreting, and gonadotroph pituitary adenomas

A comparison between the diagnostic value of gonadotropins, alpha- subunit, and chromogranin-A and their response to thyrotropin-releasing hormone in clinically nonfunctioning, alpha-subunit-secreting, and gonadotroph pituitary adenomas

Gonadotropin Release by Clinically Nonfunctioning and Gonadotroph Pituitary Adenomasin Vivoandin Vitro: Relation to Sex and Effects of Thyrotropin-Releasing Hormone, Gonadotropin-Releasing Hormone, and Bromocriptine

We studied in vivo hormone levels and in vitro hormone and subunit release in a group of 22 patients who were operated upon because of a clinically nonfunctioning or gonadotroph pituitary adenoma. In vivo, 5 of the 22 patients, all men, had hypersecretion of FSH, LH beta, or alpha-subunit. An elevated ratio of serum alpha-subunit to LH and FSH was found in 6 of 8 women in vivo, although in all 6 women serum LH, FSH, and alpha-subunit levels were low. LH, FSH, alpha-subunit, LH beta, or a combination of these glycoprotein hormones could be demonstrated in 19 of 22 cultured adenomas. We conclude that 1) virtually all clinically nonfunctioning adenomas contain or release gonadotropins or their subunits in vitro; 2) in vivo hypersecretion of these hormones and subunits occurs infrequently, and in this series only in men; 3) an elevated ratio of alpha-subunit to LH and FSH is frequently found in women and may prove to be a useful diagnostic tool; 4) responses to TRH and bromocriptine do not depend on baseline gonadotropin levels, either in vitro or in vivo, implying that the distinction between gonadotroph adenomas and adenomas without hypersecretion of gonadotropins in vivo is absent where hormone dynamics are concerned.