A potential impact of SARS-CoV-2 on pituitary glands and pituitary neuroendocrine tumors.

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 compared to normal controls (p < 0.001), but was dramatically decreased in critical cases compared to non-critical patients (p = 0.003). CONCLUSIONS: This study revealed a potential impact of SARS-CoV-2 infection on corticotroph cells and adenomas.

Knockdown of TRIM32 inhibits tumor growth and increases the therapeutic sensitivity to temozolomide in glioma in a p53-dependent and -independent manner.

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.

The KBTBD6/7-DRD2 axis regulates pituitary adenoma sensitivity to dopamine agonist treatment.

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.

Multidisciplinary team efforts improve the surgical outcomes of sellar region lesions during pregnancy.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Exosome-Transmitted lncRNA H19 Inhibits the Growth of Pituitary Adenoma.

CONTEXT: Our previous study demonstrated that the expression of long noncoding RNA (lncRNA) H19 was frequently downregulated in human primary pituitary adenomas and negatively correlated with tumor progression. However, the role of exosomal lncRNA H19 in the inhibition of pituitary tumor growth remains unclear. OBJECTIVE: To investigate whether exosomal H19 could be transported across the cell membrane to exert its inhibitory effect on pituitary tumor growth. DESIGN: Empty lentivirus GH3 cells with or without H19 overexpression were used to establish a xenograft model. Isolated exosomes were identified by transmission electron microscopy, nanoparticle tracking, and Western blotting. The expression levels of serum exosomal H19 from 200 healthy subjects and 206 patients with various subtypes of pituitary tumors were detected by ultracentrifugation and quantitative real-time PCR. RESULTS: The growth of distal tumor cells was inhibited by transferring exosomal H19, which could be transported through cell membrane and exert its inhibitory effect. Cabergoline increased H19 expression and played a synergic therapeutic effect with exosomal H19. Exosomal H19 inhibited phosphorylation of the mTORC1 substrate 4E-BP1. Of note, the expression level of exosomal H19 in the patients with all subtypes of pituitary tumors was significantly lower than that in the healthy subjects. The change of plasma exosomal H19 level may be correlated with the prognosis or drug response of the patients. CONCLUSION: Exosomal H19 inhibits the growth of distal pituitary tumors through inhibiting 4E-BP1 phosphorylation. Plasma exosomal H19 may serve as an important biomarker for predicting medical responses of patients with prolactinomas.

DEPTOR inhibits cell proliferation and confers sensitivity to dopamine agonist in pituitary adenoma.

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, ßTrCP1, 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.

Treatment of recurrent malignant gliomas with 13-cis-retinoic acid naphthalene triazole.

Glioblastoma multiforme and anaplastic astrocytoma are challenges to clinical biologists at present. The patients with glioblastoma have median survival of less than 12 months, despite advances in radiotherapeutical, chemotherapeutical and conventional surgical modalities. Retinoic acids are known to effect in vitro proliferation, differentiation, and apoptosis in colon, prostate, lung, and leukemia cancers. Retinoids are known to have anti-proliferation, anti-migration, and anti-invasive activity against human malignant gliomas, suggesting that retinoids are suitable anticancer agents to inhibit progression of tumors. Recurrent malignant cerebral gliomas have been treated with ATRA and 13-cis RA. However, the side effects associated with the use of high doses of retinoic acid demand for some more potent derivative free from such effects. The present clinical trials are undertaken to investigate the clinical safety and possible efficacy of administering retinoic acid naphthalene triazole (RANT) to patients with recurrent malignant gliomas. The toxicities observed in the patients during RANT treatment were mild. These preliminary results suggest that RANT is more potent compared to RA against recurrent malignant gliomas.

Neutrophil gelatinase-associated lipocalin as an early marker of acute kidney injury in patients with traumatic brain injury.

BACKGROUND: Recent studies have shown that urinary neutrophil gelatinase-associated lipocalin (NGAL) is rapidly up-regulated early after murine renal injury, and in patients after cardiac surgery or patients critically ill with multiple trauma. In this study, we evaluated urinary NGAL levels as a potential biomarker of early acute kidney injury (AKI) in patients with severe traumatic brain injury (TBI). METHODS: All patients with severe TBI admitted to our neurosurgical intensive care unit from March to September 2011 were enrolled prospectively. Urinary NGAL was measured using a chemiluminescent microparticle immunoassay upon admission and at 24 and 48 hours after TBI. The presence of AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. RESULTS: Using AKIN criteria, a total of 13 patients were identified with AKI, an incidence of 24%. Those who subsequently developed AKI had a striking rise in urinary NGAL early after TBI and a sustained increase over the entire duration of the study. The urinary NGAL level of the AKI group was significantly higher than the group without AKI at all time points. Using a cutoff value of 53.9 ng/mL, the area under the receiver-operating characteristic curve for urinary NGAL at 48 hours was 0.876 with a sensitivity of 0.69 and specificity of 0.95. CONCLUSIONS: Increased urinary NGAL is associated with an increased occurrence of AKI in patients with severe TBI. It is possible that urinary NGAL could provide a screening tool for AKI immediately after severe TBI, and this may in turn allow early intervention to ameliorate the adverse effects of AKI.