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Background Pituitary neuroendocrine tumors (PitNETs) are common intracranial tumors that are classified into seven histological subtypes, including lactotroph, somatotroph, corticotroph, thyrotroph, gonadotroph, null cell, and plurihormonal PitNETs. However, the molecular characteristics of these types of PitNETs are not completely clear. Methods A total of 180 consecutive cases of PitNETs were collected to perform RNA sequencing. All subtypes of PitNETs were distinguished by unsupervised clustering analysis. We investigated the regulation of TPIT by TRIM65 and its effects on ACTH production and secretion in ACTH-secreting pituitary cell lines, as well as in murine models using biochemical analyses, confocal microscopy, and luciferase reporter assays. Results A novel subtype of PitNETs derived from TPIT lineage cells was identified as with normal TPIT transcription but with lowered protein expression. Furthermore, for the first time, TRIM65 was identified as the E3 ubiquitin ligase of TPIT. Depending on the RING domain, TRIM65 ubiquitinated and degraded the TPIT protein at multiple Lys sites. In addition, TRIM65-mediated ubiquitination of TPIT inhibited POMC transcription and ACTH production to determine the fate of the novel subtype of PitNETs in vitro and in vivo. Conclusion Our studies provided a novel classification of PitNETs and revealed that the TRIM65-TPIT complex controlled the fate of the novel subtype of PitNETs, which provides a potential therapy target for Cushing’s disease.

ACT001, derived from traditional herbal medicine, is a novel compound with effective anticancer activity in clinical trials. However, little is known regarding its role in pituitary adenomas. Here, we demonstrated that ACT001 suppressed cell proliferation and induced cell death of pituitary tumor cells in vitro and in vivo. ACT001 was also effective in suppressing the growth of different subtypes of human pituitary adenomas. The cytotoxic mechanism ACT001 employed was mainly related to autophagic cell death (ACD), indicated by autophagosome formation and LC3-II accumulation. In addition, ACT001-mediated inhibitory effect decreased when either ATG7 was downregulated or cells were cotreated with autophagy inhibitor 3-methyladenine (3-MA). RNA-seq analysis showed that mitogen-activated protein kinase (MAPK) pathway was a putative target of ACT001. Specifically, ACT001 treatment promoted the phosphorylation of JNK and P38 by binding to mitogen-activated protein kinase kinase 4 (MEK4). Our study indicated that ACT001-induced ACD of pituitary tumor cells via activating JNK and P38 phosphorylation by binding with MEK4, and it might be a novel and effective anticancer drug for pituitary adenomas.

Purpose The dopamine agonists (DA) have been used widely to treat prolactinomas. However, it is difficult to predict whether the patient will be responsive to DA treatment. Methods We aimed to investigate whether the in vivo expression of DRD2 based on 18F-fallypride PET/MR could predict the therapeutic effect of DA on prolactinomas. Seven patients with prolactinomas who underwent surgery and further tumor immunohistochemistry completed 18F-fallypride PET/MR preoperatively. Imaging findings and immunohistochemical staining were compared with treatment outcomes. Results 18F-fallypride PET/MR was visually positive in 7 of 7 patients, and DRD2 target specificity could be confirmed by immunohistochemical staining. A significantly lower tracer standard uptake value (SUV) could be detected in the resistant patients (n = 3) than in the sensitive patients (n = 4; SUVmean, 4.67 ± 1.32 vs. 13.57 ± 2.42, p 18F-fallypride PET/MR corresponded with the DA treatment response. Conclusion 18F-fallypride PET/MR represents an effective diagnostic tool to predict DA response in patients with prolactinoma.

Background A growing awareness regarding all molecular mechanisms involved in both tumor shrinkage and hormonal control might allow for medical treatment of pituitary neuroendocrine tumors (PitNETs), especially macroadenomas, rather than surgery. However, there are still no effectively therapeutic targets and corresponding drugs for all subtypes of PitNETs. Methods To identify druggable cell-intrinsic vulnerabilities and correspondingly promising therapeutic agents, we examined 3 PitNETs cell lines and 21 PitNETs patient-derived primary cell cultures in sequential quantitative high-throughput screens (HTS) of 2149 FDA-approved and bio-active targeted drugs. Furthermore, we verified the most effective drug which targeted the class of mechanistic vulnerabilities, histone deacetylase (HDAC) in vitro and in vivo PitNETs models. Further RNA sequencing was employed to reveal underlying molecular mechanisms following treatment with the most effective HDAC inhibitor, panobinostat. Results The HTS effort generated a total of 55296 single-agent dose responses which were enriched among multiple inhibitors for relevant PitNETs oncogenic targets, including HDAC, Akt/mTOR, proteasome, mitogenactivated protein kinase (MEK), and phosphoinositide-3-kinase (PI3K). Inhibitors from these mechanistic classes demonstrated a relatively wide potency-range, with HDAC inhibitors being, on average, the most potent drug class. Further in vitro and In vivo testing in PitNETs models validated HDACi, especially panobinostat as a promising therapeutic approach. Transcriptional surveys revealed substantial alterations to the oxidative redox mediated by the Akt/mTOR1/4EBP1/Nuclear factor-E2-related factor 2 (Nrf2) antioxidant signaling pathway following treatment with panobinostat. Conclusion The current study revealed a class of newfound anti-tumor drugs, HDACi based on the HTS technology, which may be potential drugs for the treatment of PitNETs. Presentation: No date and time listed

Introduction: Angiotensin-converting enzyme 2 (ACE2) is the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The effects of SARS-CoV-2 on normal pituitary glands function or pituitary neuroendocrine tumors (PitNETs) have not yet been elucidated. Thus, the present study aimed to investigate the potential risks of SARS-CoV-2 infection on the impairment of pituitary glands and the development of PitNETs.Methods: PitNETs tissues were obtained from 114 patients, and normal pituitary gland tissues were obtained from the autopsy. The mRNA levels of ACE2 and angiotensin II receptor type 1 (AGTR1) were examined by quantitative real-time PCR. Immunohistochemical staining was performed for ACE2 in 69 PitNETs and 3 normal pituitary glands. The primary tumor cells and pituitary cell lines (MMQ, GH3 and AtT-20/D16v-F2) were treated with diminazene aceturate (DIZE), an ACE2 agonist, with various dose regimens. The pituitary hormones between 43 patients with SARS-CoV-2 infection were compared with 45 healthy controls.Results: Pituitary glands and the majority of PitNET tissues showed low/negative ACE2 expression at both the mRNA and protein levels, while AGTR1 showed high expression in normal pituitary and corticotroph adenomas. ACE2 agonist increased the secretion of ACTH in AtT-20/D16v-F2 cells through downregulating AGTR1. The level of serum adrenocorticotropic hormone (ACTH) was significantly increased in COVID-19 patients as compared to normal controls (pConclusion: This study revealed a potential impact of SARS-CoV-2 infection on corticotroph cells and adenomas.

Intracerebral hemorrhage is a complicated disorder with limited proven prognostic and therapeutic targets and elusive mechanisms. With proteomic methods, we aimed to explore the global protein expression profile of perihematomal tissue from ICH patients and identify potential pathophysiological pathways and protein markers. Using iTRAQ-labeling quantitative proteomics technology, four ICH brain sample and four non-ICH brain samples were analyzed. Among the 3740 quantifiable proteins, 884 were dysregulated in the patients compared to those in the controls (p

Pituitary adenoma (PA) is one of the most common intracranial tumors, and approximately 40% of all PAs are prolactinomas. Dopamine agonists (DAs), such as cabergoline (CAB), have been successfully used in the treatment of prolactinomas. The expression of dopamine type 2 receptor (DRD2) determines the therapeutic effect of DAs, but the molecular mechanisms of DRD2 regulation are not fully understood. In this study, we first demonstrated that DRD2 underwent proteasome-mediated degradation. We further employed the yeast two-hybrid system and identified kelch repeat and BTB (POZ) domain containing 7 (KBTBD7), a substrate adaptor for the CUL3-RING ubiquitin (Ub) ligase complex, as a DRD2-interacting protein. KBTBD6/7 directly interacted with, and ubiquitinated DRD2 at five ubiquitination sites (K221, K226, K241, K251, and K258). CAB, a high-affinity DRD2 agonist, induced DRD2 internalization, and cytoplasmic DRD2 was degraded via ubiquitination under the control of KBTBD6/7, the activity of which attenuated CAB-mediated inhibition of the AKT/mTOR pathway. KBTBD7 knockout (KO) mice were generated using the CRISPR-Cas9 technique, in which the static level of DRD2 protein was elevated in the pituitary gland, thalamus, and heart, compared to that of WT mice. Consistently, the expression of KBTBD6/7 was negatively correlated with that of DRD2 in human pituitary tumors. Moreover, KBTBD7 was highly expressed in dopamine-resistant prolactinomas, but at low levels in dopamine-sensitive prolactinomas. Knockdown of KBTBD6/7 sensitized MMQ cells and primary pituitary tumor cells to CAB treatment. Conversely, KBTBD7 overexpression increased CAB resistance of estrogen-induced in situ rat prolactinoma model. Together, our findings have uncovered the novel mechanism of DRD2 protein degradation and shown that the KBTBD6/7-DRD2 axis regulates PA sensitivity to DA treatment. KBTBD6/7 may thus become a promising therapeutic target for pituitary tumors.

Intracerebral hemorrhage (ICH) is a devastating subtype of stroke because it has few viable therapeutic options to intervene against primary or second brain injury. Recently, evidence has suggested that ferroptosis, a nonapoptotic form of cell death, is involved in ICH. In this study, we examined whether ICH-induced neuron death is partly ferroptotic in humans and assessed its temporal and spatial characteristics in mice. Furthermore, the ferroptosis inhibitor ferrostatin-1 (Fer-1) was used to examine the role of ferroptosis after ICH. Fold changes in ferroptosis-related gene expression, intracellular iron levels, malondialdehyde (MDA) levels, and both protein levels and cellular localization of cyclooxygenase-2 (COX-2) were measured to monitor ferroptosis. Transmission electron microscopy (TEM) was also performed to examine the ultrastructure of cells after ICH. We found that the expression level of prostaglandin-endoperoxide synthase (PTGS2) was increased in both in vitro and in vivo ICH models; by comparison, expression level of RPL8 was increased in human brain tissue. In mice, iron and MDA levels were significantly increased 3 h after ICH; COX-2 levels were increased at 12 h after ICH and peaked at 3 days after ICH; COX-2 colocalized with NeuN (a neuronal biomarker); and TEM showed that shrunken mitochondria were found at 3 h, 3 days, and 7 days after ICH. Moreover, ICH-induced neurological deficits, memory impairment and brain atrophy were reduced by Fer-1 treatment. Our results demonstrated that neuronal ferroptosis occurs during the acute phase of ICH in brain areas distant from the hematoma and that inhibition of ferroptosis by Fer-1 exerted a long-term cerebroprotective effect.

DEP domain-containing mechanistic target of rapamycin (mTOR)-interacting protein (DEPTOR) is an important modulator of mTOR, a highly conserved kinase whose hyperactivation is critically involved in a variety of human tumors. The role of DEPTOR playing in pituitary adenoma (PA) is largely unknown. Here, we reported that DEPTOR was downregulated in PA tissues, especially dopamine-resistant prolactinomas. Consistently, overexpression of DEPTOR inhibited pituitary tumor GH3 and MMQ cells proliferation in vitro and in vivo, and sensitized GH3 and MMQ cells to cabergoline (CAB), a dopamine agonist (DA). Conversely, knockdown of DEPTOR promoted GH3 and MMQ cells proliferation, and conferred cells resistance to CAB. Mechanistically, DEPTOR inhibited both mTOR Complex 1 (mTORC1) and 2 (mTORC2) activities in PA cells. In addition, DEPTOR expression level was increased to suppress mTOR kinase activity via decreasing E3 ubiquitin ligase, βTrCP1, in response to CAB. Furthermore, DEPTOR enhanced autophagy-dependent cell death to confer cells sensitivity to CAB. Taken together, our results suggest that DEPTOR may be a potential target for the treatment of PAs.

To date, the management of dopamine agonist (DA)-resistant prolactinomas remains a major clinical problem. Previously, we determined that miRNA-93 expression increases in DA-resistant prolactinomas; however, the role of miRNA-93 in the DA resistance remains largely unexplored. Hence, this study aimed to investigate the susceptibility of tumor cells to cabergoline (CAB) and the autophagy changes in MMQ and GH3 cells after miRNA-93 overexpression or inhibition. We used bioinformatics to identify the potential target of miRNA-93. Subsequently, we analyzed the correlation between miRNA-93 and autophagy-related 7 (ATG7) using protein expression analysis and luciferase assays. Furthermore, the change in the effect of miRNA-93 was measured after ATG7 overexpression. miRNA-93 expression was elevated in DA-resistant prolactinomas, whereas the expression of its identified target, ATG7, was downregulated. miRNA-93 overexpression suppressed the cytotoxic effect of CAB in MMQ and GH3 cells. In contrast, miRNA-93 downregulation enhanced CAB efficiency and promoted cell autophagy, eventually resulting in apoptosis. These results were further confirmed in in vivo xenograft models in nude mice. ATG7 overexpression could reverse the inhibitory effect of miRNA-93 on CAB treatment. Taken together, our results suggest that miRNA-93 mediates CAB resistance via autophagy downregulation by targeting ATG7 and serves as a promising therapeutic target for prolactinoma.

Aberrant expression of long noncoding RNA H19 has been associated with tumour progression, but the underlying molecular tumourigenesis mechanisms remain largely unknown. Here, we report that H19 expression is frequently downregulated in human primary pituitary adenomas and is negatively correlated with tumour progression. Consistently, upregulation of H19 expression inhibits pituitary tumour cell proliferation in vitro and tumour growth in vivo. Importantly, we uncover a function of H19, which controls cell/tumour growth through inhibiting function of mTORC1 but not mTORC2. Mechanistically, we show that H19 could block mTORC1-mediated 4E-BP1 phosphorylation without affecting S6K1 activation. At the molecular level, H19 interacted with 4E-BP1 at the TOS motif and competitively inhibited 4E-BP1 binding to Raptor. Finally, we demonstrate that H19 is more effective than cabergoline treatment in the suppression of pituitary tumours. Together, our study uncovered the role of H19-mTOR-4E-BP1 axis in pituitary tumour growth regulation that may be a potential therapeutic target for human pituitary tumours., LncRNA H19 has been shown to be aberrantly expressed in different cancers. Here, the authors show that H19 lncRNA is downregulated in pituitary adenomas and H19 is able to impede pituitary tumorigenesis via disruption of 4E-BPB1 and Raptor interaction to inhibit the phosphorylation of 4E-BP1.

Therapeutic agents for refractory prolactinomas that are resistant to dopamine agonists (DAs) are troublesome, and surgery often only removes a large part of the tumor without complete remission. Among the various second-line treatment regimens, the treatment effect of the alkylating agent temozolomide (TMZ) is only effective for approximately half of patients; however, complete remission is rare. Here we report a patient with prolactinoma who was resistant to high-dose cabergoline (CAB) treatment, demonstrating a continuous increase in both the tumor volume and the prolactin (PRL) level. Given that this case is a refractory prolactinoma, the patient underwent two transsphenoidal approach (TSA) surgeries. The pathological analysis indicated that the Ki-67 index increased significantly from 3% to 30%, and the expression levels of DRD2 and MGMT were low. Finally, TMZ treatment was recommended. A total of six cycles of TMZ standard chemotherapy shrank the tumor volume and the tumor disappeared completely. During the 6-month follow-up period, the tumor did not relapse again, and the PRL level was also normal. RNA sequencing and DNA whole genome sequencing were performed on this prolactinoma specimen, revealing 16 possible gene mutations, including a missense mutation of the PABPC1 gene. Additionally, the copy number variation analysis results showed that several chromosomes had copy number gains compared to the matched peripheral blood sample. In this case, low expression of DRD2 and high proliferation led to resistance to CAB, whereas low MGMT expression contributed to sensitivity to TMZ treatment. The results of genome sequencing still need further investigation at the molecular level to explain the tumor aggressiveness and high sensitivity to TMZ.

Tripartite motif protein 32 (TRIM32), an E3 ubiquitin ligase, has been reported to participate in many human cancers. However, the underlying role of TRIM32 in glioma remains largely unknown. Here, we aimed to explore the function of TRIM32 in glioma cells and the clinical implications and found that TRIM32 was upregulated in glioma tissues. Consistently, overexpression of TRIM32 promoted glioma U87 and U251 cell proliferation and conferred cell resistance to temozolomide (TMZ). Conversely, knockdown of TRIM32 inhibited glioma cells proliferation in vitro and in vivo and sensitized glioma cells to the treatment of TMZ in a p53-dependent and -independent manner. Mechanistically, knockdown of TRIM32 induced apoptosis of U87 an U251 cells. In addition, TRIM32 interacted with the antiapoptotic proteins BCL-xL and BCL-w, which antagonized the inhibitory effect of TRIM32 knockdown in U87 cells. Together, our study uncovered the role of TRIM32 in glioma and TRIM32 may be a potential therapeutic target for gliomas.

Pituitary adenoma (PA) is one of the most common intracranial tumors, and approximately 40% of all PAs are prolactinomas. Dopamine agonists (DAs), such as cabergoline (CAB), have been successfully used in the treatment of prolactinomas. The expression of dopamine type 2 receptor (DRD2) determines the therapeutic effect of DAs, but the molecular mechanisms of DRD2 regulation are not fully understood. In this study, we first demonstrated that DRD2 underwent proteasome-mediated degradation. We further employed the yeast two-hybrid system and identified kelch repeat and BTB (POZ) domain containing 7 (KBTBD7), a substrate adaptor for the CUL3-RING ubiquitin (Ub) ligase complex, as a DRD2-interacting protein. KBTBD6/7 directly interacted with, and ubiquitinated DRD2 at five ubiquitination sites (K221, K226, K241, K251, and K258). CAB, a high-affinity DRD2 agonist, induced DRD2 internalization, and cytoplasmic DRD2 was degraded via ubiquitination under the control of KBTBD6/7, the activity of which attenuated CAB-mediated inhibition of the AKT/mTOR pathway. KBTBD7 knockout (KO) mice were generated using the CRISPR-Cas9 technique, in which the static level of DRD2 protein was elevated in the pituitary gland, thalamus, and heart, compared to that of WT mice. Consistently, the expression of KBTBD6/7 was negatively correlated with that of DRD2 in human pituitary tumors. Moreover, KBTBD7 was highly expressed in dopamine-resistant prolactinomas, but at low levels in dopamine-sensitive prolactinomas. Knockdown of KBTBD6/7 sensitized MMQ cells and primary pituitary tumor cells to CAB treatment. Conversely, KBTBD7 overexpression increased CAB resistance of estrogen-induced in situ rat prolactinoma model. Together, our findings have uncovered the novel mechanism of DRD2 protein degradation and shown that the KBTBD6/7-DRD2 axis regulates PA sensitivity to DA treatment. KBTBD6/7 may thus become a promising therapeutic target for pituitary tumors.

The aim of this study is to compare the efficacy of bromocriptine (BRC) versus cabergoline (CAB) in patients with giant prolactinomas. We searched MEDLINE, EMBASE, CENTRAL and Clinical Trials.gov for studies dated before March 1st, 2016, that used BRC or CAB for the treatment of patients with giant prolactinomas. Specific eligibility criteria were set to identify articles and cases. The selected articles were reviewed, and the data were extracted for analysis. The compared outcomes included tumor shrinkage, tumor response, normalization of prolactin (PRL) level, and visual field defect (VFD) improvement. Gender differences were also considered. Differences between the groups were assessed using Student's t test and the chi-square test. Two hundred and forty-five records were identified, and 10 articles and 104 cases met the inclusion criteria. Based on our analysis, CAB is significantly better than BRC in normalizing PRL levels in patients, especially males, with giant prolactinomas (69.4% versus 31.7%, p = 0.01). However, there was no significant difference between the two drugs in terms of tumor shrinkage, tumor response and VFD improvement (p > 0.05) in male or female patients. CAB exhibits significantly better efficacy than BRC in the normalization of PRL levels in male patients with giant prolactinomas. Regarding tumor reduction and VFD improvement, both drugs are comparably effective for patients of both genders. This quantitative and systematic review provides preliminary evidence in favor of CAB as a medical therapy for treating giant prolactinomas in male patients, especially those with extremely high PRL levels.

Background The authors report the case of a 34-year-old man who presented with intractable hiccups. The imaging examination showed that the patient was suffering from syringomyelia associated with Chiari type I malformation. Case Descriptions The patient underwent posterior fossa decompression combined with bilateral tonsillectomy and duroplasty. The intractable hiccups completely resolved 1 week after operation and had not recurred at 2 months after surgery. Postoperative magnetic resonance imaging showed the atrophy of the tonsils of the cerebellum and disappearance of the cavities of the spinal cord. Conclusions Intractable hiccups as the main symptoms of Chiari type I malformation are extremely rare in the clinic. Decompression surgery should be an appropriate method to relieve the symptoms.

Objective To identify biomarkers key to invasiveness of the 3 subtypes of nonfunctioning pituitary adenomas (NFPAs) and provide a guidance for therapeutic decision making and identification of potential adjuvant drugs. Methods Fifty NFPA tumor tissues obtained from transsphenoidal surgery were used in the study. Three invasive NFPAs and 4 noninvasive NFPAs were used for gene expression microarray analyses. In addition, there are 5 invasive NFPAs and 4 noninvasive NFPAs used for proteomic analyses. Invasive-related biomarkers were identified by bioinformatics analysis by integrating the transcriptomics and proteomics data sets. All 3 subtypes of NFPAs (null cell adenomas, oncocytomas, and gonadotroph adenomas) were used to validate differentially expressed candidate biomarkers by means of quantitative real-time reverse transcription polymerase chain reaction and Western blot. The level of EZR was downregulated in pituitary adenoma cell line GH3 to investigate the invasive effect of EZR on GH3 cells by using the RNA interference technique. Results Eight genes involved in the invasion function were found by bioinformatics analysis, and the EZR gene was identified as a novel invasive-related biomarker in the 3 subtypes of NFPAs. The expression level of EZR was found higher in terms of invasiveness than the noninvasive ones of the 3 subtypes of NFPAs. Moreover, the knockdown of EZR inhibited the invasion of GH3 cells in vitro. Conclusions EZR is a novel biomarker in terms of invasion among the 3 subtypes of NFPAs, and it is a promising guide for therapeutic decision making as well.

Cabergoline is a dopamine agonist that has been used as the first-line treatment option for prolactin-secreting pituitary adenomas for several decades. It not only suppresses hormone production from these prolactinomas, but also causes tumour shrinkage. Recent studies revealed some novel mechanisms by which cabergoline suppresses tumour cell proliferation and induces cell death. In this article, we review the most recent findings in cabergoline studies, focusing on its anti-tumour function. These studies suggest the potential broader clinical use of cabergoline in the treatment of other tumours such as breast cancer, pancreatic neuroendocrine tumours, and lung cancer.

Treatment of space-occupying lesions (SOLs) in the sellar region is a clinical challenge, especially in pregnant women because many treatment decisions are restrained due to pregnancy. We attempt to discuss the surgical indications and timing for pregnant patients and highlight the importance of multidisciplinary team (MDT) treatment. From August 2017 to February 2018, four pregnant women were admitted to our hospital with severe visual impairment due to sellar region SOLs, including two cases of tuberculum sellae meningioma, one case of giant pituitary adenoma and one case of a pituitary abscess. All four patients were safely treated by surgery during the second and third trimesters of pregnancy through concerted efforts of the MDT, including a neurosurgeon as the team leader in combination with experts in obstetrics, ophthalmology and endocrinology. The SOLs were removed completely from all four patients, resulting in significantly improved vision without operation-related complications. Pregnancy continued postoperatively to full-term delivery in three of the four patients. The other patient with a pituitary abscess selected to terminate the pregnancy at a gestational age of 20 weeks because of her own concerns. The four babies (including a pair of twins) were born healthy and had developed normally at the 6-week postpartum follow-up. With the MDT guiding the decision-making process, surgical resection of sellar region SOLs in pregnant women with severe visual impairment is practical to improve the prognosis without affecting the outcomes of pregnancy for either the mother or the infant.

Dopamine agonists (DAs), such as cabergoline and bromocriptine, are the first-line clinical treatment for prolactinomas. Our previous study demonstrated that long noncoding RNA H19 expression is frequently downregulated in human primary pituitary adenomas and is negatively correlated with tumor progression. However, the significance and mechanism of H19 in the DA treatment of prolactinomas are still unknown. In this study, we reported that H19 had a synergistic effect with DA treatment on prolactinomas in vitro and in vivo. Mechanistically, H19 promoted ATG7 expression in pituitary tumor cells by inhibiting miR-93a expression. In addition, a potential binding site between miR-93 and H19 was confirmed, and low expression of miR-93 was previously found in DA-resistant prolactinomas. Furthermore, we showed that miR-93a regulates ATG7 expression by targeting ATG7 mRNA. In conclusion, our study has identified the role of the H19-miR-93-ATG7 axis in DA treatment of prolactinomas, which may be a potential therapeutic target for human prolactinomas.

Dopamine agonists (DAs) are the first-line treatment of prolactinomas. They function through the dopamine 2 receptor (D2R) in the tumor cells. Endocan, also called endothelial cell-specific molecule-1 (ESM1), has been described as a marker of neoangiogenesis. However, whether ESM1 promotes the resistance of prolactinomas to DA therapy is largely unknown. In our study, 25 patients with prolactinomas were divided into resistant- and sensitive- groups according to the clinical response to bromocriptine. We found that ESM1-microvessel density of resistant prolactinomas was significantly higher than that of sensitive prolactinomas (47.9 ± 11.6, n = 8, vs 13.1 ± 2.8, n = 17, p = 0.0006), indicating that ESM1 was a DA resistance-related gene. Immunostaining showed that ESM1 was expressed in tumor vessels and sporadic tumor cells, and ESM1 was overlapped with the Smooth Muscle Actin (SMA) and von Willebrand Factor (VWF) in the tumor vessels. Silencing of ESM1 markedly suppressed the viability of GH3 and MMQ cells in vitro, and furthermore, significantly increased the sensitivity of GH3 and MMQ cells to DA treatment. Additionally, silencing of ESM1 down-regulated the angiogenesis-associated genes, such as VEGFR2, FGF2, CD34, CD31, VWF, and EGFR. Knockdown of ESM1 decreased endothelial tube formation of HUVECs, and significantly increased the sensitivity of HUVECs to Avastin treatment. Therefore, we first demonstrate that DA resistance-related ESM1 promotes the angiogenesis and tumor cells growth of prolactinomas, suggesting that ESM1 may be a novel therapeutic target for prolactinomas.

Cabergoline (CAB), the first-line drug for treatment of prolactinomas, is effective in suppressing prolactin hypersecretion, reducing tumor size, and restoring gonadal function. However, mechanisms for CAB-mediated tumor shrinkage are largely unknown. Here we report a novel cytotoxic mechanism for CAB. CAB induced formation of autophagosome in rat pituitary tumor MMQ and GH3 cells at the early stage through inhibiting mTOR pathway, resulting in higher conversion rates of LC3-I to LC3-II, GFP-LC3 aggregation, and increased autophagosome formation. Interestingly, CAB treatment augmented lysosome acidification and resulted in impaired proteolytic degradation within autolysosomes. This blocked the autophagic flux, leading to the accumulation of p62 aggregation and undigested autolysosomes. Knockdown of ATG7, ATG5, or Becn1, could significantly rescue the CAB-mediated cell death of MMQ cells (p < 0.05). CAB-induced autophagy and blockade of autophagy flux participated in antitumoral action in vivo. In conclusion, our study provides evidence that CAB concomitantly induces autophagy and inhibits the autophagic flux, leading to autophagy-dependent cell death. These findings elucidate novel mechanisms for CAB action.

Few studies have specifically focused on the effect of cabergoline on invasive giant prolactinomas (IGPs) resistant to bromocriptine. This study aims to evaluate whether cabergoline could be used as an effective therapy for patients with bromocriptine-resistant IGPs. This retrospective study included 15 patients with bromocriptine-resistant IGPs who received treatment at our department during 2007–2015. Cabergoline was administered in all 15 patients, with the dose adjusted depending on the prolactin response of each patient. Parameters for outcome assessment included prolactin level, pituitary function, tumor size, improvement of the clinical symptoms, visual field defects, drug tolerance, and disease recurrence. Cabergoline was effective for the treatment of the patients with bromocriptine -resistant IGPs as represented by normalization of the prolactin level in 12/15 patients; improvement or normalization of the pituitary function in 4/5 patients with hypopituitarism; significant reduction in tumor size in 14/15 patients; and relief of the clinical symptoms in 11/15 patients. All 15 patients showed good tolerance to cabergoline. In addition, no recurrence was observed during the mean follow-up period of 63.47 (range 30–145) months. Data of this retrospective study demonstrate that cabergoline is an excellent option for the treatment of patients with bromocriptine-resistant IGPs.

Background and importance Metastasis to the pituitary gland is uncommon in patients with systemic disseminated cancer. Individual articles have reported cases of pituitary metastasis mimicking a prolactinoma, but no case of a prolactin-secreting tumor metastasizing to the pituitary mimicking a prolactinoma has been reported so far. Clinical presentation This article reports a 67-yr-old man with a recent onset of headaches, ophthalmoplegia, hypopituitarism, and hyperprolactinemia who was initially diagnosed with prolactinoma and given bromocriptine in the local hospital. Because of vomiting after taking drugs, he was transferred to our hospital for further diagnosis and treatment. Serum prolactin was elevated up to 1022 ng/mL, and pituitary magnetic resonance imaging revealed a 2.9 × 2.8 × 2.3 cm sellar mass with pituitary apoplexy, for which endoscopic transsphenoidal surgery was performed. Postoperative pathology and western blotting disclosed a prolactin-positive metastatic lung adenocarcinoma. Whole exome sequencing revealed a number of gene mutations including KRAS, PIK3CA, ALK, and CTNNB1. The patient died of deterioration of the lung disease 3 mo after the initial diagnosis. Conclusion To the best of our knowledge, this is the first report of a prolactin-secreting tumor metastasizing to the pituitary mimicking a prolactinoma as confirmed by both immunohistochemistry and western blot. Prolactin secretion is rare and elusive, and may associate with specified gene mutations.

Background Germinomas are sensitive to radiotherapy and chemotherapy. However, there has been no report involving in the potential therapeutic effect of dopamine agonists (DAs) such as bromocriptine on germinomas. Case description A 20-year-old female was presented with bitemporal visual disturbance and amenorrhea. Magnetic resonance imaging demonstrated a huge sellar tumor with upward extension and invasion of the parasellar region. The blood tests showed an exceedingly high level of prolactin. A sellar tumor with hyperprolactinemia was diagnosed, and bromocriptine was initially given. After three months, the tumor volume had been obviously decreased by 82%. However, the tumor re-grew after ten months and the endoscopic endonasal surgery was performed. Histopathological and immunohistochemical examination indicated the patient had a pure sellar germinoma. The tumor cells strongly expressed dopamine 2 receptor and dopamine 5 receptor, which located in the membrane and cytoplasm. Conclusions The transient but significant partial responsiveness of germinoma to bromocriptine treatment in this patient is a novel discovery, suggesting that DAs may be a potential therapeutic choice for tumors with the expression of dopamine 2/5 receptors.

Heat shock protein 47 (HSP47) is a collagen-binding protein, which has been recently found to express in glioma vessels. However, the expression profile of HSP47 in glioma patients and the underlying mechanisms of HSP47 on glioma angiogenesis are not fully explored. In the current study, we found that expression of HSP47 in glioma vessels was correlated with the grades of gliomas. HSP47 knockdown by siRNAs significantly decreased cell viability in vitro and tumor volume in vivo; moreover, it reduced the microvessel density (MVD) by CD31 immunohistochemistry in vivo. HSP47 knockdown significantly inhibited tube formation, invasion and proliferation of human umbilical vein endothelial cells (HUVECs). Furthermore, conditional medium derived from HSP47 knockdown cells significantly inhibited HUVECs tube formation and migration, while it increased chemosensitivity of HUVECs cells to Avastin. Silencing of HSP47 decreased VEGF expression in glioma cells consistently, and reduced glioma vasculature. Furthermore, HSP47 promoted glioma angiogenesis through HIF1α-VEGFR2 signaling. The present study demonstrates that HSP47 promotes glioma angiogenesis and highlights the importance of HSP47 as an attractive therapeutic target of GBM.

Dopamine agonists such as bromocriptine and cabergoline have been successfully used in the treatment of pituitary prolactinomas and other neuroendocrine tumors. However, their therapeutic mechanisms are not fully understood. In this study we demonstrated that DRD5 (dopamine receptor D5) agonists were potent inhibitors of pituitary tumor growth. We further found that DRD5 activation increased production of reactive oxygen species (ROS), inhibited the MTOR pathway, induced macroautophagy/autophagy, and led to autophagic cell death (ACD) in vitro and in vivo. In addition, DRD5 protein was highly expressed in the majority of human pituitary adenomas, and treatment of different human pituitary tumor cell cultures with the DRD5 agonist SKF83959 resulted in growth suppression, and the efficacy was correlated with the expression levels of DRD5 in the tumors. Furthermore, we found that DRD5 was expressed in other human cancer cells such as glioblastomas, colon cancer, and gastric cancer. DRD5 activation in these cell lines suppressed their growth, inhibited MTOR activity, and induced autophagy. Finally, in vivo SKF83959 also inhibited human gastric cancer cell growth in nude mice. Our studies revealed novel mechanisms for the tumor suppressive effects of DRD5 agonists, and suggested a potential use of DRD5 agonists as a novel therapeutic approach in the treatment of different human tumors and cancers.

MicroRNAs (miRNA) have been implicated in the resistance of tumors to chemotherapy. However, little is known about miRNA expression in bromocriptine-resistant prolactinomas. In this study, 23 prolactinoma samples were classified as bromocriptine-sensitive or -resistant according to the clinical definition of bromocriptine resistance, and their miRNA expression profiles were determined using Solexa sequencing. We found 41 miRNAs that were differentially expressed between the two groups, and 12 of these were validated by stem-loop qRT-PCR. Hsa-mir-93, hsa-mir-17, hsa-mir-22*, hsa-mir-126*, hsa-mir-142-3p, hsa-mir-144*, hsa-mir-486-5p, hsa-mir-451, and hsa-mir-92a were up-regulated and hsa-mir-30a, hsa-mir-382, and hsa-mir-136 were down-regulated in bromocriptine-resistant prolactinomas in comparison with bromocriptine-sensitive prolactinomas. Furthermore, silencing of mir-93 significantly increased the sensitivity of MMQ cells to dopamine agonist treatment. Mir-93 directly affected p21 expression in MMQ cells by targeting the 3'-UTR. Our study is the first to identify a miRNA expression profile associated with bromocriptine-resistant prolactinoma.

Tumor stem cells have been implicated as cancer-initiating cells in malignant brain tumors. However, whether benign brain tumors also contain tumor stem cells are largely unexplored. Here, we investigated whether tumor stem-like cells were present in pituitary adenoma similar to malignant brain tumors. By immunocytochemistry, we found that pituitary adenoma tissues expressed neural stem cell marker. These cells could form neurospheres in vitro, expressed neural stem/progenitor cell markers and generated daughter cells with the capacity to differentiate into three neural lineages. Importantly, compared with non-invasive pituitary adenomas, we found that CD133 expression was significantly increased in invasive pituitary adenomas, suggesting that the proliferative capacity was correlated with the malignance of pituitary adenomas. Finally, invasive pituitary adenomas cells displayed lower proliferative ability than glioblastoma. Our data indicate that a subpopulation of stem/progenitor-like cells are present in pituitary adenomas, and these cells may be responsible for benign tumor initiation and maintenance.

Immunotherapy strategies targeting glioma stem-like cells (GSCs) hold promise for improving outcomes in glioblastoma patients. We used the A2B5 monoclonal antibody to classify GSCs derived from the mouse GL261 glioma cell line, and A2B5+ GL261 cell lysate-pulsed dendritic cells (DCs) were used to treat mouse glioma. We found that such DCs elicited a stronger specific cytotoxic T lymphocyte response against A2B5+ GL261 cells than A2B5– GL261 cell lysate-pulsed DCs. The effect of A2B5+ GL261 cell lysate-pulsed DCs in vivo depended on when the vaccination was started. In the tumor cell adaptation phase, C57BL/6 mice had an immune response against GL261, and vaccination enhanced the immune response and prevented glioma formation in 37.5 % of mice. In contrast, after glioma formation, the immune response against GL261 was decreased, and vaccination had no therapeutic effect. Our findings suggest that vaccination with A2B5+ GL261 cell lysate-pulsed DCs only has some glioma preventive effect.