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Pituitary carcinoma is a rare and aggressive malignancy with a poor prognosis and few effective treatment options. A 35-year-old woman presented with an aggressive ACTH-secreting pituitary adenoma that initially responded to concurrent temozolomide and capecitabine prior to metastasizing to the liver. Following treatment with ipilimumab and nivolumab, the tumor volume of the dominant liver metastasis reduced by 92%, and the recurrent intracranial disease regressed by 59%. Simultaneously, her plasma ACTH level decreased from 45,550 pg/mL to 66 pg/mL. Both prospective clinical sequencing with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets and retrospective whole-exome sequencing were performed to characterize the molecular alterations in the chemotherapy-naive pituitary adenoma and the temozolomide-resistant liver metastasis. The liver metastasis harbored a somatic mutational burden consistent with alkylator-induced hypermutation that was absent from the treatment-naive tumor. Resistance to temozolomide treatment, acquisition of new oncogenic drivers, and subsequent sensitivity to immunotherapy may be attributed to hypermutation. Combination treatment with ipilimumab and nivolumab may be an effective treatment in pituitary carcinoma. Clinical sequencing of pituitary tumors that have relapsed following treatment with conventional chemotherapy may identify the development of therapy-induced somatic hypermutation, which may be associated with treatment response to immunotherapy.

Cushing disease is a condition in which the pituitary gland releases excessive adrenocorticotropic hormone (ACTH) as a result of an adenoma arising from the ACTH-secreting cells in the anterior pituitary. ACTH-secreting pituitary adenomas lead to hypercortisolemia and cause significant morbidity and mortality. Pituitary-directed medications are mostly ineffective, and new treatment options are needed. As these tumors express EGFR, we tested whether EGFR might provide a therapeutic target for Cushing disease. Here, we show that in surgically resected human and canine corticotroph cultured tumors, blocking EGFR suppressed expression of proopiomelanocortin (POMC), the ACTH precursor. In mouse corticotroph EGFR transfectants, ACTH secretion was enhanced, and EGF increased Pomc promoter activity, an effect that was dependent on MAPK. Blocking EGFR activity with gefitinib, an EGFR tyrosine kinase inhibitor, attenuated Pomc expression, inhibited corticotroph tumor cell proliferation, and induced apoptosis. As predominantly nuclear EGFR expression was observed in canine and human corticotroph tumors, we preferentially targeted EGFR to mouse corticotroph cell nuclei, which resulted in higher Pomc expression and ACTH secretion, both of which were inhibited by gefitinib. In athymic nude mice, EGFR overexpression enhanced the growth of explanted ACTH-secreting tumors and further elevated serum corticosterone levels. Gefitinib treatment decreased both tumor size and corticosterone levels; it also reversed signs of hypercortisolemia, including elevated glucose levels and excess omental fat. These results indicate that inhibiting EGFR signaling may be a novel strategy for treating Cushing disease.

There are five subtypes of somatostatin receptors (SST1‐5), which are expressed in several types of solid neoplasms, neuroendocrine tumors, and pituitary adenomas. Most commonly, SST2 and SST5, are of interest regarding diagnostic, treatment, and prognostic purposes. In this article the basic biological characteristics of SST are briefly reviewed, and focus given to the immunohistochemical evaluation of SST2 and SST5 in growth hormone (GH)‐secreting pituitary tumors, and their quantification as predictors of response to treatment with somatostatin receptor ligands (SRL), the mainstay of the pharmacological therapy available for these tumors. Although many different scoring systems for SST2 immunohistochemistry showing correlation with SRL response have been reported, among which the immunoreactivity score (IRS) has been the most consistently used, a universally validated immunohistochemical technique and scoring scheme is lacking. Efforts should be made on collaborative multicenter studies aiming at validating homogeneous immunostaining protocols and a scoring system for SST2 and SST5 expression, to help clinicians to define the optimal therapeutic strategy for the patients with somatotroph tumors. This article reviews the major biological characteristics of somatostatin receptors (SST2 and SST5) in anterior pituitary tumors, and the immunohistochemical evaluation of their expression as predictors of response to pharmacological therapy with SST ligands.

Abstract Context Cushing disease (CD) is a life-threatening disorder. Therapeutic goals include symptom relief, biochemical control, and tumor growth inhibition. Current medical therapies for CD by and large exert no action on tumor growth. Objective To identify drugs that inhibit corticotroph tumor adrenocorticotropic hormone (ACTH) secretion and growth. Design High throughput screen employing a novel “gain of signal” ACTH AlphaLISA assay. Setting Academic medical center. Patients Corticotroph tumor tissues from patients with CD. Interventions None. Main outcome measures Potent inhibitors of corticotroph tumor ACTH secretion and growth. Results From a kinase inhibitor library, we identified the dual PI3K/HDAC inhibitor CUDC-907 as a potent inhibitor of murine and human corticotroph tumor ACTH secretion (median effective concentration 1-5 nM), and cell proliferation (median inhibitory concentration 5 nM). In an in vivo murine corticotroph tumor xenograft model, orally administered CUDC-907 (300 mg/kg) reduced corticotroph tumor volume (TV [cm3], control 0.17 ± 0.05 vs CUDC-907 0.07 ± 0.02, P < .05) by 65% and suppressed plasma ACTH (ACTH [pg/mL] control 206 ± 27 vs CUDC-907 47 ± 7, P < .05) and corticosterone (corticosterone [ng/mL] control 180 ± 87 vs CUDC-907 27 ± 5, P < .05) levels by 77% and 85% respectively compared with controls. We also demonstrated that CUDC-907 acts through HDAC1/2 inhibition at the proopiomelanocortin transcriptional level combined with its PI3K-mediated inhibition of corticotroph cell viability to reduce ACTH secretion. Conclusions Given its potent efficacy in in vitro and in vivo models of CD, combined with proven safety and tolerance in clinical trials, we propose CUDC-907 may be a promising therapy for CD.

Abstract Context Acromegaly registries constitute a valuable source of therapeutic outcome information in real-life. Objective The objective of this work is to analyze surgical and pharmacological outcomes in the Mexican Acromegaly Registry (MAR). Design and Methods Data were extracted from the MAR informatic platform. Surgical remission was defined by a postoperative postglucose (GH) of less than 1 ng/mL and an insulin-like growth factor 1 (IGF-1) of less than 1.2 × upper limit of normal (ULN). Pharmacological remission was defined by a basal GH of less than 1 ng/mL and an IGF-1 of less than 1.2 × ULN. Results A total of 650 surgical outcomes were analyzed (94.6% transsphenoidal). Surgical remission was achieved in 40.15%, whereas 44.15% remained biochemically active. Persistently active disease after surgery was significantly associated with harboring an invasive macroadenoma, a basal GH of greater than 10 ng/mL, and/or an IGF-1 of greater than 2 × ULN at diagnosis on bivariate and multivariate analysis. The outcome of monotherapy with first-generation somatostatin analogs (SSAs) was evaluated in 267 patients (adjunctive in 65%), of whom 28.4% achieved remission. Persistently active disease was significantly associated with harboring an invasive macroadenoma as well as with pretreatment basal GH and IGF-1 levels of greater than 10 ng/mL and greater than 2 × ULN, respectively, on bivariate and multivariate analysis. Combined therapy with SSA and cabergoline was analyzed in 100 patients, of whom 19% achieved remission and 44% remained active; in this subset of patients, only a pretreatment IGF-1 of greater than 2 × ULN was significantly associated with persistent disease activity. Conclusion Surgical and pharmacological outcomes in acromegaly are highly dependent on tumor size/invasiveness as well as on the degree of hypersomatotropinemia.

Background Targets of acromegaly treatment are normalization of biochemical values, removal/reduction/stabilization of the pituitary mass, control of clinical activity and mortality with a multimodal/multidisciplinary approach. Despite significant technological and pharmacological progress, still several patients with acromegaly bear a resistant somatotroph adenoma and active disease may persist for many years with resultant poor clinical outcomes. Aim To review briefly definition and pathophysiology of resistance to acromegaly treatment and the options of medical treatment in this context, exploring the role of novel clinical and molecular biomarkers in the personalization of therapy and proposing updates to the currently available guidelines for the treatment of resistant GH-secreting adenomas. Conclusions In the last few years, in parallel with the increased number of medical options available for the therapy of acromegaly, relevant advances occurred in the understanding of the role of novel molecular and clinical biomarkers in predicting the responsiveness to second-line medical treatments, such as Pegvisomant and Pasireotide LAR, and helping clinicians in the personalization of the follow-up and treatment of resistant somatotroph adenomas. The integration of these findings into the existing guidelines may represent a possibly important step forward in the management of “difficult” acromegaly patients.

ContextRemission failure following transsphenoidal surgery in Cushing disease (CD) from pituitary corticotroph tumors (CtTs) remains clinically challenging. Histone deacetylase inhibitors (HDACis) are antitumor drugs approved for clinical use, with the potential to affect adrenocorticotropin hormone (ACTH) hypersecretion by inhibiting pro-opiomelanocortin (POMC) transcription.ObjectiveTesting the efficacy of suberoylanilide hydroxamic acid (SAHA) on human and murine ACTH-secreting tumor (AtT-20) cells.DesignCell viability, ACTH secretion (enzyme-linked immunosorbent assay), apoptosis, and gene expression profile were investigated on AtT-20 cells. In vivo efficacy was examined in an athymic nude mouse AtT-20 xenograft model. SAHA efficacy against human-derived corticotroph tumor (hCtT) (n = 8) was tested in vitro.SettingNational Institutes of Health.InterventionSAHA (0.5 to 8 µM).Main Outcome MeasuresAtT-20 and hCtT cell survival, in vitro/invivo ACTH measurements.ResultsSAHA (1 µM) reduced AtT-20 viability to 75% at 24 hours, 43% at 48 hours (analysis of variance; P = 0.002). Apoptosis was confirmed with elevated BAX/Bcl2 ratio and FACS. Intriguingly, early (3-hour) significant decline (70%; P < 0.0001) of secreted ACTH and diminished POMC transcription was observed with SAHA (1 µM). Microarray analysis revealed a direct association between liver X receptor alpha (LXRα) and POMC expression. Accordingly, SAHA reduced LXRα in AtT-20 cells but not in normal murine corticotrophs. Xenografted nude-mice tumor involution (126 ± 33/160 ± 35 vs 337 ± 49 mm3; P = 0.0005) was observed with 5-day intraperitoneal SAHA, with reversal of elevated ACTH (P < 0.0001). SAHA did not affect serum ACTH in nontumor mice. Lastly, we confirmed that SAHA (1 µM/24 h) decreased hCtT survival (78.92%; P = 0.0007) and ACTH secretion (83.64%; P = 0.03).ConclusionOur findings demonstrate SAHA’s efficacy in reducing survival and ACTH secretion in AtT-20 and hCtT cells, providing a potential intervention for recurrent/unremitting CD.SAHA efficacy was tested on human/murine ACTH-secreting tumor cells. It successfully reduced survival and ACTH secretion, offering potential novel treatment of recurrent/unremitting Cushing disease.

The most frequent cause of endogenous hypercortisolism is Cushing disease (CD), a devastating condition associated with severe comorbidities and high mortality. Effective tumor-targeting therapeutics are limited. Search in PubMed with key words \"corticotroph\" and \"Cushing's disease\" plus the name of the mentioned therapeutic agent and in associated references of the obtained papers. Additionally, potential therapeutics were obtained from ClinicalTrials.gov with a search for \"Cushing disease.\" At present, the tumor-targeted pharmacological therapy of CD is concentrated on dopamine agonists (cabergoline) and somatostatin analogs (pasireotide) with varying efficacy, escape from response, and considerable side effects. Preclinical studies on corticotroph pathophysiology have brought forward potential drugs such as retinoic acid, silibinin, and roscovitine, whose efficacy and safety remain to be determined. For many patients with CD, effective tumor-targeted pharmacological therapy is still lacking. Coordinated efforts are pivotal in establishing efficacy and safety of novel therapeutics in this rare but devastating disease.

BACKGROUND AND IMPORTANCE:Rarely, corticotrophic pituitary tumors take on an aggressive form characterized by rapid growth, invasion into local structures, compression of cranial nerves, and possible spread to distant sites. When conventional surgery, radiation therapy, and hormones fail to control progression and symptoms, alternative therapies are needed. A novel chemotherapeutic regimen of capecitabine and temozolomide (CAPTEM), originally designed in our laboratory, demonstrated dramatic antineoplastic effects against corticotrophic pituitary tumors. CLINICAL PRESENTATION:We present a case series of 4 patients with aggressive, adrenocorticotrophic hormone--producing pituitary tumors who had previously depleted all surgical, radiation, and hormonal therapies and were then treated with CAPTEM. Dramatic clinical improvements in neurological deficits and Cushing symptoms were evident in all patients after treatment was initiated. Confirmed by radiographic imaging, 2 of 4 patients demonstrated complete regression of disease, 1 patient had a 75% regression, and the fourth patient has ongoing stable disease for > 4.5 years at the time of this writing. Immunohistochemical analysis of patients’ tumor samples showed low O-methyguanyl methyltransferase expression and adequate levels of mismatch repair enzymes (MLH-1, MSH-2, MSH-6, and PMS-2), which are important for the in vivo efficacy of CAPTEM. CONCLUSION:This is the first report of prolonged antitumor response to and radiographic complete remissions as a result of CAPTEM in patients with aggressive pituitary tumors who had exhausted all other therapies. ABBREVIATIONS:ACTH, adrenocorticotrophic hormoneCAPTEM, capecitabine and temozolomideCN, cranial nerve5-FU, 5-fluorouracilMGMT, O-methyguanyl methyltransferaseNET, neuroendocrine tumorPFS, progression-free survivalRECIST, Response Evaluation Criteria in Solid Tumors