Wei Lian

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.

Pituitary abscess following transsphenoidal surgery: The experience of 12 cases from a single institution

OBJECTIVE To explore possible reasons for the incidence of a pituitary abscess following transsphenoidal surgery and determine the most effective treatment. METHODS A series of 12 patients who had undergone transsphenoidal surgery in other hospitals before being treated at Peking Union Medical College Hospital were reviewed. The presence of a pituitary abscess was confirmed when pus was intraoperatively observed within the sella turcica. All patients were treated with debridement of the abscess, nine among whom through a transsphenoidal approach and the other three via a craniotomy, followed by antibiotic treatment and hormone replacement therapy. The mean follow-up time was 27.0 months (range from 3.0 to 79.0 months). RESULTS Headache (92%), panhypopituitarism (58%) and visual disturbance (50%) were the most common clinical indicators of a pituitary abscess. Imaging tests demonstrated a pituitary mass in all patients, with seven (58%) manifested with typical magnetic resonance features of an abscess. Ten patients (83%) were correctly diagnosed preoperatively. During surgical exploration, six presented with severe inflammation or an abscess within the sphenoidal sinus. Causative organisms were identified in five patients (42%). After surgical and antibiotic therapies, all patients fully recovered except for two presenting with severe visual impairment. Six patients (50%) required hormone replacement therapy. CONCLUSION Retrograde infection from the sphenoid sinus may be a vital mechanism underlying the formation of a pituitary abscess following transsphenoidal surgery. Debridement of the abscess through surgical approaches combined with antibiotic treatment has been found to yield positive outcomes.

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.

Transsphenoidal surgery in a patient with acromegaly and McCune–Albright syndrome: application of neuronavigation

The McCune-Albright syndrome (MAS) is characterized by a clinical triad of polyostotic fibrous dysplasia, café-au-lait hyperpigmented macules, and hypersecretory endocrinopathies. Acromegaly is an uncommon manifestation of the endocrine disturbance associated with MAS, and the role of surgery in managing these cases has been a topic of debate. The authors present the case of a 35-year-old man with MAS who was also diagnosed with acromegaly, hyperprolactinemia, and pituitary macroadenoma. The patient had an 18-year history of fibrous dysplasia involving the right frontal bone and ribs as well as multiple endocrinopathies, but no cutaneous hyperpigmented macules. An oral glucose tolerance test demonstrated partial suppression of plasma levels of growth hormone (GH). The patient underwent transsphenoidal resection of the pituitary tumor, performed with assistance of neuronavigation, and tolerated the procedure well. After the surgery, both prolactin and GH levels returned to normal. These results suggest that neuronavigation-assisted transsphenoidal surgery can safely remove pituitary adenomas associated with MAS and successfully treat the underlying endocrine abnormalities.

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.

Study on the Expression Levels of CXCR4, CXCL12, CD44, and CD147 and Their Potential Correlation with Invasive Behaviors of Pituitary Adenomas

OBJECTIVE To evaluate the factors of CXCR4, CXCL12, CD44, and CD147 as early potential diagnostic biomarkers by determining their expression levels in invasive and non-invasive pituitary adenomas. METHODS Fresh pituitary adenoma specimens were collected from 35 pituitary adenoma (21 invasive and 14 non-invasive) patients who underwent surgical treatment in our Neurosurgery Department between January and April of 2009. The expression levels of CXCR4, CXCL12, CD44, and CD147 were evaluated firstly by flow cytometry, fluorescence microscopy in single cell suspensions, and then by immunohistochemical staining of paraffin tissue sections. RESULTS Flow cytometric analyses showed that the percentage of CXCR4- and CXCL12-positive cells from invasive pituitary adenomas (IPA) was significantly higher in the single cell suspensions than that from non-invasive pituitary adenomas (nIPA) (P<0.05). Immunohistochemical staining revealed that CXCR4 and CXCL12 staining index scores of the invasive pituitary adenomas were significantly higher than those of the non-invasive pituitary adenomas (P<0.05). In contrast, neither flow cytometry nor immunohistochemical staining demonstrated significant difference between CD44 and CD147 expression levels, respectively. CONCLUSION Expression levels of CXCR4 and CXCL12 are correlated with the invasiveness of pituitary adenomas. Therefore, rather than CD44 and CD147, CXCR4 and CXCL12 may potentially serve as biomarkers for early detection of pituitary adenomas.

Cardiovascular System Changes and Related Risk Factors in Acromegaly Patients: A Case-Control Study

Background. Cardiovascular complications are known to be the main determinants of reduced life expectancy and decreased quality of life in acromegaly patients. Our study aimed to provide insight into the cardiovascular changes that occur in acromegaly patients and to investigate the correlative risk factors. Methods. A total of 108 patients definitively diagnosed with acromegaly and 108 controls matched for age and gender were recruited into study and control groups, respectively. Standard echocardiography was performed on all of the participants, and data were collected and analyzed. Results. All acromegaly patients presented with structural cardiac changes, including a larger heart cavity, thicker myocardial walls, and increased great vessel diameters compared with the control group. Additionally, the acromegaly patients presented with reduced diastolic function. Aging and increased body mass index (BMI) were correlated with myocardial hypertrophy and diastolic dysfunction; a longer disease duration was correlated with larger great vessel diameters. Conclusions. Ageing and increased BMI are independent risk factors for acromegalic cardiomyopathy, and a long disease duration results in the expansion of great vessels. Increased efforts should be made to diagnose acromegaly at an early stage and to advise acromegaly patients to maintain a healthy weight.

Refractory pituitary adenoma: a novel classification for pituitary tumors

Pituitary adenomas are classified as typical or atypical, invasive or noninvasive, and aggressive or nonaggressive based on pathological features, radiological findings, and clinical behavior. Only pituitary tumors with cerebrospinal and/or systemic metastasis are considered malignant carcinomas. However, some pituitary adenomas with high Ki-67 indexes exhibit aggressive behaviors, such as rapid growth, early and frequent recurrence, and resistance to conventional treatment, even in the absence of metastasis. Novel terminology is needed to define these tumors. Here, we propose the use of the term “refractory pituitary adenoma” to define malignant pituitary tumors exhibiting 1) a high Ki-67 index and rapid growth, 2) early and high frequency of recurrence, 3) resistance to conventional treatments and/or salvage treatment with temozolomide (TMZ), 4) poor prognosis, 5) and a lack of cerebrospinal or systemic metastases. To illustrate the utility of this refractory pituitary adenoma classification and the difficulty in managing disease in these patients, we examined twelve clinical cases. Correctly identifying refractory pituitary adenomas is crucial for improving patient prognoses. Early identification might encourage the early use of aggressive therapeutic strategies to prevent or delay recurrence.

Schwannoma in Sellar Region Mimics Invasive Pituitary Macroadenoma: Literature Review With One Case Report.

AbstractIn central nervous system, schwannomas, as ubiquitous tumors, mostly originate from sensory nerves like auditory and trigeminal nerves. However, intrasellar schwannomas are extremely rare. They are often misdiagnosed as pituitary adenomas.We report a rare case of schwannoma in the sellar region—a challenging diagnosis guided by clinical presentations, radiological signs, and postoperative pathological test.We represent a 65-year-old woman who had suffered from headaches, hypothyroidism, and visual disturbance. Her MRI revealed an abnormal sellar region mixed-signal mass lesion with suprasellar, left parasellar, and sellar floor invasiveness. We present detailed analysis of the patients disease course and review relevant literatures. Written informed consent was obtained from the patient for publication of this article. A copy of the written consent is available for review by the editors of MEDICINE. Because this article does not involve any human or animal trials, there is no need to conduct special ethic review and the ethical approval is not necessary.When surgically treated, her specimen revealed a typical histopathology pattern of schwannoma. The patients symptoms improved a lot after surgery and he continues to be under observation.Despite its rarity, intrasellar schwannoma should be considered in the differential diagnosis of sellar lesions that mimic pituitary adenomas.