Xiaohai Liu

Inhibition of PI3K/AKT/mTOR Pathway Enhances Temozolomide-Induced Cytotoxicity in Pituitary Adenoma Cell Lines in Vitro and Xenografted Pituitary Adenoma in Female Nude Mice

Invasive pituitary adenomas (PAs) are often refractory to standard therapy and salvage treatment with temozolomide (TMZ). Hyperactivation of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway contributes to chemotherapy resistance in many cancers. XL765, a novel dual-PI3K/mTOR inhibitor, has recently shown its efficacy as a monotherapy and in combination with conventional therapeutics in many cancers. The hyperactive PI3K/AKT/mTOR pathway frequently occurs in invasive PAs. In this study, we investigated whether XL765 sensitizes PA cells to TMZ in vitro and in vivo. Experiments were carried out to evaluate the effect of XL765 and TMZ alone or in combination on cell proliferation and apoptosis of PA cell lines (αT3-1, GH3, and MMQ) in vitro as well as the tumor growth and serum GH and prolactin secretions in a GH3 xenograft tumor model of female nude mice. XL765 and TMZ synergistically inhibited the growth of PA cell lines and induced apoptosis. Combination of XL765 and TMZ synergistically inhibited tumor growth, decreased serum GH and prolactin levels, and reduced the sacrifice rate of GH3 xenograft tumor models without increased systemic side effects. In addition, XL765 in combination with TMZ dramatically decreased phosphorylation of AKT and mTOR as well as the expression of Bcl-2. The increased expression of cleaved poly (ADP-ribose) polymerase and Bcl-2-associated X protein along with elevated caspase-3/7 activity were also observed in the combination group. Therefore, dual inhibitors of PI3K and mTOR may enhance alkylating agent-mediated cytotoxicity and provide a novel regimen in the treatment of invasive PAs.

Pyrimethamine sensitizes pituitary adenomas cells to temozolomide through cathepsin B-dependent and caspase-dependent apoptotic pathways.

Invasive pituitary adenomas (PAs) are generally refractory to conventional therapy and salvage treatment with temozolomide (TMZ). In addition to antiprotozoan effects, pyrimethamine (PYR) has recently shown its strong antitumor activity as an antineoplastic agent or in combination with TMZ in metastatic melanoma cells. In this study, the effects of TMZ, PYR or TMZ/PYR combination on rat/mouse PA cell lines αT3‐1, GH3, MMQ and ATt‐20 as well as GH3 xenograft tumor model were evaluated. TMZ/PYR combination synergistically inhibited proliferation, invasion and induced apoptosis of these PA cell lines in vitro. Strikingly, combination treatment with TMZ and PYR produced synergistic antitumor activity and enhanced the survival rate of GH3 xenograft tumor models without increasing systemic side effects. In addition, TMZ/PYR induced cell cycle arrest, increased DNA damage, upregulated the expression of cathepsin B, BAX, cleaved PARP and phosphorylated histone H2AX as well as elevated caspase3/7, 8 and 9 activities. The decreased expression of Bcl‐2, MMP‐2 and MMP‐9 alone with cytochrome c release from mitochondria into the cytosol was also observed in the TMZ/PYR combination group. The increase in cell apoptosis due to combination with PYR was rescued by leucovorin. These data suggest that PYR may enhance the efficacy of TMZ via triggering both cathepsin B‐dependent and caspase‐dependent apoptotic pathways. Therefore, combination of PYR and TMZ may provide a novel regimen for invasive PAs refractory to standard therapy and TMZ.

Screening for AIP gene mutations in a Han Chinese pituitary adenoma cohort followed by LOH analysis

OBJECTIVE The aryl hydrocarbon receptor interacting protein gene (AIP) is associated with pituitary adenoma (PA). AIP has not been sequenced in East Asian PA populations, so we performed this study in a Han Chinese cohort. DESIGN Our study included six familial PA pedigrees comprising 16 patients and 27 unaffected relatives, as well as 216 sporadic PA (SPA) patients and 100 unrelated healthy controls. METHODS AIP sequencing was carried out on genomic DNA isolated from blood samples. Multiplex ligation-dependent probe amplification and microsatellite marker analyses on DNA from the paired tumor tissues were performed for loss of heterozygosity analysis. RESULTS We identified three common and four rare single nucleotide polymorphisms (SNPs), one intron insertion, one novel synonymous variant, four novel missense variants, and a reported nonsense mutation in three familial isolated PA (FIPA) cases from the same family. Large genetic deletions were not observed in the germline but were seen in the sporadic tumor DNA from three missense variant carriers. The prevalence of AIP pathogenic variants in PA patients here was low (3.88%), but was higher in somatotropinoma patients (9.30%), especially in young adults (≤30 years) and pediatric (≥18 years) paients (17.24% and 25.00% respectively). All AIP variant patients suffered from macroadenomas. However, the AIP mutation rate in FIPA families was low in this cohort (16.67%, 1/6 families). CONCLUSION AIP gene mutation may not be frequent in FIPA or SPA from the Han Chinese population. AIP sequencing and long-term follow-up investigations should be performed for young patients with large PAs and their families with PA predisposition.

Differential expression of folate receptor alpha in pituitary adenomas and its relationship to tumor behavior.

BACKGROUND Folate receptor alpha (FRα) plays a pivotal role in the tumorigenesis of some malignant tumors, but its role and clinical significance in pituitary adenomas remain unclear. OBJECTIVE To identify a possible biomarker for the diagnosis of nonfunctional pituitary adenomas (NFAs) that could also be used to assess tumor behavior. METHODS Sporadic pituitary tumor specimens (n = 76) and normal pituitary glands (n = 7) were examined. FRα protein and mRNA expression were quantified by immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction, respectively. We verified the differential expression of FRα in pituitary adenomas and evaluated the associations of FRα expression with Ki-67 labeling index (LI) and clinicopathologic characteristics of NFAs. Statistical significance was determined by using the Student t test or one-way analysis of variance. RESULTS FRα mRNA and protein was uniquely overexpressed in NF (immunohistochemically positive) and NF (immunohistochemically negative) adenomas but not in functional adenomas (adrenocorticotropic hormone, growth hormone, and prolactin) or normal adenohypophysial tissues (P < .001). The expression of FRα was positively correlated with tumor invasiveness, size and Ki-67 LI in NFAs. CONCLUSION FRα may play an important role in the development and progression of NFAs. Therefore, FRα may be useful as a molecular biomarker for the diagnosis of NFAs and assessment of tumor invasiveness.

Antiproliferative, Antiinvasive, and Proapoptotic Activity of Folate Receptor α-Targeted Liposomal Doxorubicin in Nonfunctional Pituitary Adenoma Cells

There is an urgent need for novel therapeutic strategies for the treatment of nonfunctional pituitary adenomas (NFPAs), especially those that are invasive. The folate receptor (FR)α is overexpressed in several cancers, including NFPA. The aim of this study was to determine the efficacy of FRα-targeted liposomes loaded with doxorubicin (F-L-DOX) in the treatment of NFPA. We evaluated targeting, cytotoxicity, antiinvasive, and proapoptotic activity of F-L-DOX in 25 primary cell lines derived from patients with NFPAs. We found that these liposomes effectively targeted NFPA cells through FRα and that endocytosis of the liposomes was blocked by 1mM free folic acid. F-L-DOX inhibited proliferation of NFPA cells and promoted apoptosis through activation of caspase-8, caspase-9, and caspase-3/7 more effectively than L-DOX. Furthermore, F-L-DOX also exerted greater antiinvasive ability in NFPA cells than L-DOX through suppression of the secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9. Addition of 1mM free folic acid significantly reduced the pleotropic effects of F-L-DOX in NFPA cells, suggesting that FRα plays a critical role in mediating the antitumor effect of F-L-DOX. Our findings warrant further investigation of F-L-DOX as an alternative therapeutic strategy for the treatment of NFPAs that express FRα.

Correlations of Pituitary Tumor Transforming Gene Expression with Human Pituitary Adenomas: A Meta-Analysis

Objective Pituitary tumor transforming gene (PTTG) is an important paracrine growth factor involved in early lactotrope transformation and early onset of angiogenesis in pituitary hyperplasia. Emerging evidences have shown that PTTG expression may contribute to the etiology of pituitary adenomas; but individually published studies showed inconclusive results. This meta-analysis aimed to derive a more precise estimation of the correlations of PTTG expression with human pituitary adenomas. Methods A range of electronic databases were searched: MEDLINE (1966∼2013), the Cochrane Library Database (Issue 12, 2013), EMBASE (1980∼2013), CINAHL (1982∼2013), Web of Science (1945∼2013) and the Chinese Biomedical Database (CBM) (1982∼2013) without language restrictions. Meta-analysis was performed using the STATA 12.0 software. Crude odds ratio (OR) or standard mean difference (SMD) with its corresponding 95% confidence interval (95%CI) were calculated. Results Twenty-four clinical cohort studies were included with a total of 1,464 pituitary adenomas patients. The meta-analysis results revealed that patients with invasive pituitary adenomas had higher positive expression of PTTG than those of non-invasive patients (OR  = 6.68, 95%CI  = 3.72–11.99, P<0.001). We also found a significant difference in microvessel density between invasive and non-invasive patients (SMD  = 1.81, 95%CI  = 0.39–3.23, P = 0.013). However, there were no significant difference in PTTG expression between functional and non-functional patients with pituitary adenomas (OR  = 1.11, 95%CI  = 0.58–2.10, P = 0.753). No publication bias was detected in this meta-analysis (all P>0.05). Conclusion This present meta-analysis suggests that PTTG expression may be associated with tumor invasiveness and microvessel density of pituitary adenomas, while no correlations with functional status was found.

Tumour Lateralization in Cushing's disease by Inferior Petrosal Sinus Sampling with desmopressin

Bilateral inferior petrosal sinus sampling (IPSS) with corticotropin‐releasing hormone (CRH) is currently the gold standard in the diagnosis of Cushings disease (CD) and has also been used in tumour lateralization. Our objective was to determine the diagnostic value and lateralization accuracy of IPSS with desmopressin.

The clinical characteristics and microsurgical therapy of pituitary adenomas in elderly patients: A retrospective study of 130 cases

OBJECTIVE To investigate the clinical characteristics and microsurgical therapy of pituitary adenomas in elderly patients. METHOD This article describes a retrospective study of 130 pituitary adenomas in elderly patients over 65years of age who underwent a microsurgical operation using the transsphenoidal approach and were admitted to Peking Union Medical College Hospital (PUMCH) from January 2010 to December 2012. RESULTS A total of 60 (46.2%) males and 70 females (53.8%) were included, and the mean age of the patients was 68.38years. The main clinical manifestation was visual defects (35.4%), and the levels of growth hormone (GH), insulin-like growth factor-1 (IGF-1), adrenocorticotropic hormone (ACTH), and prolactin (PRL) were increased by 11.5%, 11.5%, 6.2%, and 7.7%, respectively. All patients underwent the transsphenoidal approach. The main comorbidity prior to surgery was hypertension (45.0%), and the average duration of follow-up was 39.6±10.6months. Tumor recurrence was observed in 19 patients, 17 of which received radiological therapy, and two patients underwent an additional operation at our hospital. The rate of loss to follow-up was 15.9%. CONCLUSION There was no significant difference in the surgical outcome, mortality in the perioperative period or complications between the elderly patients and the general population. However, the indications for pituitary adenomas in elderly patients still require further age-specific guidelines.

Symptomatic Rathke's Cleft Cyst with Rapid Enlargement Masquerading as Rathke's Cleft Cyst Apoplexy.

To the Editor: A 35-year-old Chinese woman was admitted to our hospital complaining of a 1-year history of bilateral temporal chronic intermittent moderate headache which used to be alleviated by ibuprofen tablets or rest and had increased in intensity in the past 1 month. The patient also presented with the slow development of visual deficit. In January 2012, the patient presented with polyuria and polydipsia suggestive of central diabetes insipidus. Endocrine studies showed no clinically significant results. The patient also underwent a brain magnetic resonance imaging (MRI) which demonstrated an ovoid sellar lesion measuring 6 mm × 6 mm, with hyperintense, with no apparent enhancement after administration of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) on T1-weighted images and iso- to hypo-intense on T2-weighted images [Figure 1a]. The patient was initially diagnosed with Rathkes cleft cyst (RCC) and refused to undergo the operation. By the end of 2013, she once again presented with polyuria and polydipsia that were in spontaneous remission in the following 6 months with no medical intervention. A radiographic follow-up was administrated in July 2014 demonstrating an ovoid sellar lesion measuring 9 mm × 11 mm × 14 mm indicative of enlargement of the former cyst, with hyperintense, with no obvious enhancement after administration of Gd-DTPA on T1-weighted images and iso- to hyper-intense on T2-weighted images [Figure 1b], and apparently, the signal characteristics of the MRI were almost the same as the initial one suggesting likely hemorrhage. From July 2014 to May 2015, she sought for medical services in the Department of Traditional Chinese Medicine and regularly took medicinal herbs aiming to promote circulation and remove stasis. In May 2015, she complained of a slightly blurred vision of her right eye. In November 2015, she was attacked by a severe unbearable headache, a visions sharp decline of the right eye, and mild right temporal hemianopsia. The pain was diffuse, dull, and persistent for a week and could not be alleviated by tablets or rest as before. Her medical history was otherwise unremarkable. The general physical examination was uneventful. The neurological examination showed an awake, alert, and completely oriented patient with no focal sign. The muscular strength and tension of her four limbs were completely normal. Various physiological reflexes could be elicited in response to external stimulus. Pathological signs were absent. The results of ophthalmologic tests were in accordance with her self-reported symptoms indicating remarkable changes of visual acuity (VA) and visual field. Preoperatively, VA of the right eye was 0.5+, and VA of the left eye was 0.8. Partial temporal hemianopia was observed with no suspect [Figure 1c]. The results of hematologic and biochemical tests were uneventful. Endocrine evaluations were within the normal ranges. MRI studies demonstrated a sellar and suprasellar lesion with hyperintense, with no apparent enhancement after administration of Gd-DTPA on T1-weighted images and hyperintense on T2-weighted images, measuring 16.8 mm × 16.0 mm × 14.6 mm [Figure 1d]. Located in the inferoposterior position of RCC, there was an irregular-shaped lesion showing hypointense on T1-weighted images and hypointense on T2-weighted images suggesting internal apoplexy. The mixed signal intensity was thought to be consistent with the symptom of apoplexy indicating intracystic old hemorrhage of RCC. Repeated MRI findings revealed the rapid enlargement of RCC within <4 years which was quite uncommon and likely to be described in published cases for the first time. The patient underwent an endoscopic endonasal transsphenoidal resection for RCC. In the procedure, the intracystic contents, which were seemingly yellowish cholesterol crystals instead of expected stale hemorrhage, were completely drained off, and the wall of RCC was resected as much as possible in a safe manner. Intracystic hemorrhage of RCC apoplexy was denied by surgical exploration. Intra- and post-operatively, leakage of cerebrospinal fluid and intracranial infection did not happen. The results of histopathological examinations proved the cystic lesion to be RCC. The patient recovered from the chronic headache; however, the visual deficits failed to improve significantly. Figure 1 T1-coronal MRI with Gd-DTPA showed enlargement of RCC during the follow-up period in 2012 (a), 2014 (b), and 2015 (d). The figure of visual field showed partial temporal hemianopia of the right side (c). MRI: Magnetic resonance imaging; Gd-DTPA: Gadolinium-diethylenetriaminepentaacetic ... According to a very limited quantity of published reports on RCC apoplexy, the prevalence of RCC apoplexy in women is higher than that in men. Clinical manifestations of the patients with RCC apoplexy are similar to those with pituitary tumor apoplexy. Chronic headache is the most dominant presentation. The headache of our patient was severe, with sudden onset which was highly suggestive of apoplexy and was believed to result from the sudden expansion of the mass in the pituitary fossa, and in the meantime, there was strong radiographic evidence of hemorrhage on MRI. The patient also complained of the deterioration of her VA of her right eye and the ophthalmological tests revealed temporal hemianopia of the right side. MRI indicated the radiographic mass effect showing a large cystic lesion which was also proven by intraoperative findings. Hemorrhage into RCC has been reported, but to our knowledge, RCC with rapid enlargement behaving like RCC apoplexy is first reported in our case. Up to now, no typical and consistent MRI features have been identified for RCC. It is suggested that the presence of a posterior ledge of the diaphragma sellae or an intracystic nodule should be pathognomonic of RCC leading to early diagnosis. The signal intensity widely varies from lesion to lesion directly depending on the biochemical nature of each intracystic material. Considering the highly variable appearances of RCC on MRI, differential radiologic diagnosis is regularly required. The patient in our case exhibited a cystic lesion in the intrasellar region with mixed signals. According to the MRI features of the patient, we regarded the cystic lesion very likely to be RCC apoplexy. However, intraoperative visualization and/or pathological confirmation of hemorrhage on the background of RCC remain the gold standard in diagnosing RCC apoplexy. The preoperative diagnosis of RCC apoplexy of our patient mainly according to MRI features was not in consistence with the gold standard. RCC, a nonneoplasm cystic mass, usually remains steadily small and asymptomatic throughout the life in most patients.[1] However, some appear clinically significant for the growth and the subsequent mass effect on the surrounding structures in the sellar region. Although RCC apoplexy is rarely reported in published data, vigilance should be raised in the differential diagnosis of cystic mass in the sellar region.[2] Surgical treatment is the optimal approach for those patients with symptomatic RCC because histopathological results and intraoperative findings of the cystic lesion remain the gold standard for diagnosing RCC or RCC apoplexy, and surgery can alleviate mass effect-related symptoms and even lead to the recovery of endocrine dysfunction.[3] Through the case report, we hope that our experience can help enrich the clinical and radiographic differential diagnosis of RCC apoplexy and the further understanding of RCC. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Diagnosis, Therapy, and Therapeutic Effects in Cases of Pituitary Metastasis

OBJECTIVE This study aimed to summarize the diagnosis, therapy, and prognosis of pituitary metastasis. METHODS Ten patients from the Department of Neurosurgery of the Peking Union Medical College Hospital from April 1997 to August 2014 were retrospectively analyzed. RESULTS The participants included 7 males (70%) and 3 females (30%), with an average age of 60.4 years. The most common initial clinical feature was visual disability (50%). The postoperative pathology reports indicated 1 case (10%) of metastatic large-cell pulmonary carcinoma, 2 cases (20%) of metastatic small cell pulmonary carcinoma, 2 cases (20%) of clear cell renal carcinoma metastasis, and 5 cases (50%) of metastasis of adenocarcinomas from different areas. All the patients underwent a thorough follow-up, and the average survival was 144 days. CONCLUSIONS Pituitary metastasis is a rare disease. Its diagnosis depends on the clinical manifestations and radiologic results. The primary therapeutic method is surgery and subsequent radiotherapy and chemotherapy; however, the prognosis of this disease is poor.