Comprehensive circular RNA profiling reveals the regulatory role of circRNA_0007694 in papillary thyroid carcinoma.

PURPOSE: The present study aimed to identify differentially expressed circRNAs in thyroid cancer and verify their potential functions. METHODS: Next-generation sequencing was used to identify differentially expressed circRNAs between papillary thyroid carcinoma (PTC) tissues and paired pericarcinomatous tissues. Polymerase chain reaction and Sanger sequencing methods successfully identified hsa_circ_0007694. A hsa_circ_0007694 over-expression vector was prepared to determine the effect of this circRNA on proliferation, migration, invasion, apoptosis, and the cell cycle in PTC cells. An in vivo animal assay was conducted by injecting PTC cells into the chests of mice. Further, RNA-seq was performed, followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, to verify the regulatory mechanism of hsa_circ_0007694. Western blotting was used to verify the genes thought to be involved in the hsa_circ_0007694 regulatory pathways based on KEGG analysis. RESULTS: We identified a circRNA, hsa_circ_0007694 that was down-regulated in PTC tissues compared to pericarcinomatous tissues. Over-expression of hsa_circ_0007694 promoted apoptosis and inhibited proliferation, migration, and invasion in PTC cells in vitro, and decreased tumor growth in vivo. Transcriptome sequence analysis suggested 129 differentially expressed genes between PTC tissue and paired pericarcinomatous tissue. KEGG analysis and western blotting indicated that the PI3K/AKT/mTOR and Wnt signaling networks are most likely to be related to hsa_circ_0007694 in thyroid cancer. CONCLUSION: The circRNA hsa_circ_0007694 is down-regulated in PTC and is therefore a potential therapeutic target.

Cabergoline versus bromocriptine for the treatment of giant prolactinomas: A quantitative and systematic review.

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.

Optimal timing of dopamine agonist withdrawal in patients with hyperprolactinemia: a systematic review and meta-analysis.

PURPOSE: Dopamine agonists (DAs) are recommended as first-line treatment for patients with hyperprolactinemia. Generally, it is accepted that patients with hyperprolactinemia do not need lifelong medication, but the optimal timing for DA withdrawal has not been determined. The aim of this systematic review and meta-analysis is to assess the impact of DA withdrawal on the clinical outcomes of patients with hyperprolactinemia, and to explore possible factors affecting successful DA withdrawal. METHODS: The databases of PubMed, Cochrane and EMBASE were searched up to May 2016. RESULTS: The proportion of patients with persisting normoprolactinemia after DA withdrawal reached 36.6% in a random effects model (95% CI, 29.4-44.2%; I-squared: 82.5%). Data of stratified analysis showed that the success rate of drug withdrawal was high in patients using cabergoline (CAB) as the only treatment (41.2%; 95% CI 32.3-50.4%) and those using CAB over 24 months (48.7%; 95% CI 38.9-58.5%), especially in patients with idiopathic hyperprolactinemia (73.2%; 95% CI 55.6-87.7%). In addition, patients who received a low maintenance dose of CAB, and had a significant reduction in tumor size (over 50%) before withdrawal, were more likely to achieve success (51.5 and 49.4%, respectively). CONCLUSION: The success rate of DA withdrawal has increased in recent years. Further, the success rate of CAB withdrawal was higher than that of bromocriptine, especially in patients with a duration of treatment longer than 24 months. Conclusively, the probability of success was higher in patients who received low-dose CAB maintenance treatment and those who achieved a significant reduction in tumor size before withdrawal.

Pituitary Tumor Suppression by Combination of Cabergoline and Chloroquine.

Context: The dopamine agonist cabergoline (CAB) has been used widely in the treatment of prolactinomas and other types of pituitary adenomas, but its clinical use is hampered by intolerance in some patients with prolactinoma and lack of effectiveness in other pituitary tumor types. Chloroquine (CQ) is an old drug widely used to treat malaria. Recent studies, including our own, have revealed that CAB and CQ are involved in induction of autophagy and activation of autophagic cell death. Objective: To test whether CAB and CQ can function cooperatively to suppress growth of pituitary adenomas as well as other cancers. Results: In vitro studies using the rat pituitary tumor cell lines MMQ and GH3, human pituitary tumor cell primary cultures, and several human cancer cell lines showed that CQ enhanced suppression of cell proliferation by CAB. These results were confirmed in in vivo xenograft models in nude mice and estrogen-induced rat prolactinomas. To understand the mechanism of combined CAB and CQ action, we established a low-CAB-dose condition in which CAB was able to induce autophagy but failed to suppress cell growth. Addition of CQ to low-dose CAB blocked normal autophagic cycles and induced apoptosis, evidenced by the further accumulation of p62/caspase-8/LC3-II. Conclusion: The data suggest that combined use of CAB and CQ may increase clinical effectiveness in treatment of human pituitary adenomas, as well as other cancers, making it an attractive option in tumor and cancer therapies.

Activation of DRD5 (dopamine receptor D5) inhibits tumor growth by autophagic cell death.

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.

Long-Term Clinical Outcomes of Invasive Giant Prolactinomas after a Mean Ten-Year Followup.

Objective. The aim of this study is to observe clinical outcomes after more than ten years of followup in a group of patients with invasive giant prolactinomas (IGPs) treated with dopamine agonists (DAs). Methods. Twenty-five patients met the criteria of IGPs, among which 16 patients primarily received bromocriptine (BRC) and the other nine had undergone unsuccessful microsurgery prior to BRC treatment. Results. After a mean follow-up period of 135.5 ± 4.7 months, the clinical symptoms in all patients improved by different degrees. Tumor volume was decreased by a mean of 98.6%, and the tumors of 19 patients had almost completely disappeared. The mean duration of treatment at maximal doses of BRC was 48.5 months. At the last follow-up visit, nineteen patients had normal PRL levels, and 14 of these patients had received the low-dose BRC treatment (at an average of 2.9 ± 0.3 mg/d). Younger patients < 25 years had a significantly higher rate of persistent hyperprolactinemia after long-term BRC treatment (p = 0.043). Conclusion. DAs are a first-line therapy for IGPs because they can effectively achieve long-term control in both shrinking tumor volume and normalizing the PRL level, and majority of patients need low-dose DA maintenance. Younger patients are prone to persistent hyperprolactinemia despite long-term DA treatment.

Dopamine agonist resistance-related endocan promotes angiogenesis and cells viability of 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.

Heat Shock Protein 47 Promotes Glioma Angiogenesis.

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.

Suppression of mTOR pathway and induction of autophagy-dependent cell death by cabergoline.

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.

A Meta-analysis of Carbon Nanoparticles for Identifying Lymph Nodes and Protecting Parathyroid Glands during Surgery.

OBJECTIVE: To investigate the ability of carbon nanoparticles (CNs) to identify lymph nodes and protect parathyroid glands during thyroid cancer surgery. DATA SOURCES: English and Chinese literature in PubMed, ClinicalTrials.gov, EMBASE, the Cochrane Database of Systematic Reviews, the China Biology Medicine Database, the China Master's and Doctoral Theses Full-Text Database, the China National Knowledge Infrastructure, the WANFANG database, and the Cqvip database (from January 2009 to July 2014). REVIEW METHODS: Studies were included if they were randomized controlled trials or nonrandomized controlled trials for thyroidectomy and central neck dissections that compared the use of CNs with methylene blue or a blank control in patients undergoing initial thyroid cancer surgery. The primary outcomes were the number of retrieved central lymph nodes and the accidental parathyroid removal rate. RESULTS: This meta-analysis identified 11 randomized controlled trials and 4 nonrandomized controlled trials comprising 1055 patients. Compared with the outcomes of the blank controls, the use of CNs resulted in an average of 2.71 more lymph nodes removed per patient (weighted mean difference = 2.71, 95% confidence interval [CI] = 1.68-3.74, P < .001), a 23% lower rate of accidental parathyroid removal (odds ratio = 0.23, 95% CI = 0.10-0.54, P = .0008), and similarly reduced rates of transient hypoparathyroidism and hypocalcemia. Compared with methylene blue, the use of CNs resulted in an average of 1.50 more lymph nodes removed per patient (weighted mean difference = 1.50, 95% CI = 0.11-2.89, P = .03) and a 5% reduction in the rate of accidental parathyroid removal (odds ratio = 0.05, 95% CI = 0.01-0.29, P = .0007). CONCLUSION: CNs partially improve the extent and accuracy of neck dissection and preserve the normal anatomic structure and physiologic function of the parathyroid glands during thyroid cancer surgery.

Glioma-associated antigen HEATR1 induces functional cytotoxic T lymphocytes in patients with glioma.

A2B5+ glioblastoma (GBM) cells have glioma stem-like cell (GSC) properties that are crucial to chemotherapy resistance and GBM relapse. T-cell-based antigens derived from A2B5+ GBM cells provide important information for immunotherapy. Here, we show that HEAT repeat containing 1 (HEATR1) expression in GBM tissues was significantly higher than that in control brain tissues. Furthermore, HEATR1 expression in A2B5+ U87 cells was higher than that in A2B5-U87 cells (P = 0.016). Six peptides of HEATR1 presented by HLA-A∗02 were selected for testing of their ability to induce T-cell responses in patients with GBM. When peripheral blood mononuclear cells from healthy donors (n = 6) and patients with glioma (n = 33) were stimulated with the peptide mixture, eight patients with malignant gliomas had positive reactivity with a significantly increased number of responding T-cells. The peptides HEATR(1682-690), HEATR(11126-1134), and HEATR(1757-765) had high affinity for binding to HLA-A∗02:01 and a strong capacity to induce CTL response. CTLs against HEATR1 peptides were capable of recognizing and lysing GBM cells and GSCs. These data are the first to demonstrate that HEATR1 could induce specific CTL responses targeting both GBM cells and GSCs, implicating that HEATR1 peptide-based immunotherapy could be a novel promising strategy for treating patients with GBM.

MicroRNA expression profile of bromocriptine-resistant prolactinomas.

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.

CTL responses to HSP47 associated with the prolonged survival of patients with glioblastomas.

OBJECTIVE: To define heat shock protein 47 (HSP47) as a novel glioma-associated antigen and to preliminarily assess the association of cytotoxic T lymphocyte (CTL) responses to HSP47 with clinical outcomes in patients with glioblastomas (GBMs). METHODS: The expression of HSP47 was determined in primary GBM tissues (n = 17) and controlled brain tissues (n = 10) by Western blot. Candidate epitope peptides were predicted using the human leukocyte antigen (HLA) Peptide Binding Predictions Program. The CTL responses to HSP47 were quantified in peripheral blood mononuclear cells from 6 healthy donors and 38 patients (benign tumors = 5, astrocytoma grade II = 7, anaplastic gliomas grade III = 10, GBMs = 16) by stimulation with the mixture of the identified peptides above. Kaplan-Meier survival curves were used to analyze the association between CTL responses and clinical outcomes. RESULTS: Expression of HSP47 was hardly detectable in controlled brain tissues and increased in GBM tissues (p = 0.018). HSP47(184-192) (KLPEVTKDV) and HSP47(3-11) (LLLLSAFCL) were predicted as the most potent candidate epitope peptides with experimentally confirmed binding affinity to the HLA-A0201 molecule. Seven of 26 patients (26.9%) with malignant gliomas had positive CTL responses. Furthermore, patients with GBM with positive CTL responses to HSP47 experienced a prolonged progress-free survival time (12.6 ± 1.3 vs 8.1 ± 3.2 months, p = 0.01) and overall survival (13.4 ± 1.3 vs 10.4 ± 2.7 months, p = 0.035) than those with negative responses. CONCLUSION: Our data demonstrated that HSP47 is a novel glioma-associated antigen. HSP47-based vaccine will likely confer additional survival benefit to patients with GBM after surgical treatment.

High-mobility group box 2 is associated with prognosis of glioblastoma by promoting cell viability, invasion, and chemotherapeutic resistance.

BACKGROUND: The expression profile of high-mobility group box 2 (HMGB2) in patients with glioblastoma multiforme (GBM) and its clinical signature with underlying mechanisms were not fully explored. METHODS: HMGB2 protein levels were measured in 51 GBM patients by immunohistochemical studies. To clarify the precise role of HMGB2 on cell invasion and viability of 3 GBM cell lines, we did in vitro and in vivo analyses with lentivirus vectors and small interfering RNA. Transwell invasion assays and wound-healing assays were used to analyze the invasion of GBM cells. Expression of p53 and matrix metalloproteinase 2/tissue inhibitors of metalloproteinase 2 (MMP2/TIMP2) protein was analyzed by Western blot. RESULTS: HMGB2 protein expression was significantly higher in GBM than in controlled brain tissues (P < .0001). HMGB2 overexpression was significantly correlated with shorter overall survival time, which was the only independent prognostic factor for overall survival in a multivariate analysis (P = .017). HMGB2 knockdown by small interfering RNA decreased cell viability and invasion in vitro and significantly decreased tumor volume in vivo, which might be involved in the change of p53 expression and the balance of MMP2/TIMP2. Moreover, silencing of HMGB2 could significantly increase the sensitivity of GBM cells to temozolomide chemotherapy. CONCLUSIONS: Our present data suggest that HMGB2 expression is a significant prognostic factor and might play an important role in cell invasion and temozolomide-induced chemotherapeutic sensitivity of GBM. This study highlights the importance of HMGB2 as a novel prognostic marker and an attractive therapeutic target of GBM.

The miR-92b functions as a potential oncogene by targeting on Smad3 in glioblastomas.

MicroRNAs(miR) play an important role in cell growth, differentiation, proliferation and apoptosis, which can function either as oncogenes or as tumor suppressors in their effect on tumor growth. Smad3 is often underexpressed in very diverse types of malignant tumors and has an important tumor suppressive function; however, the underlying mechanism in solid cancer including glioblastomas(GBM) is not fully explored. The aim of this study is to explore the role of miR-92b in regulation of smad3 in GBM. In our study, we found that miR-92b expression was significantly increased in GBM tissues compared with normal brain tissues by Q-RT-PCR and in situ hybridization (P<0.01). However, expression of smad3 in GBM samples was significantly reduced compared with normal brain tissues by western blot and immunohistochemistry (P<0.05). Using 3'UTR luciferase reporter gene assay, we found that miR-92b directly affected smad3 expression in GBM cells by targeting the 3'-untranslated region. Silencing of miR-92b was able to significantly inhibit the viability of GBM cells in three GBM cell lines through up-regulating the TGF-beta/smad3/p21 signaling pathway in vitro. Furthermore, the tumor growth and the weight of U87 cells in the miR-92b inhibitor group were significantly inhibited when compared with that of the control group in vivo. Our data demonstrated that miR-92b may be considered as a tumor oncogene to promote GBM cell proliferation, and thus may serve as a potentially useful target for development of miRNA-based therapies in the future.

[Fine-needle aspiration with measurement of parathyroid hormone levels in thyroidectomy].

OBJECTIVE: Hypoparathyroidism is one of the most serious complications of thyroidectomy. It is important to identify the parathyroid glands during thyroidectomy. In order to find an economic, simple and less traumatic way to identify the parathyroid glands and testify its feasibility, fine-needle aspiration of suspected parathyroid tissue was used to measure the parathyroid hormone (PTH) levels during the surgical procedure. METHODS: From Nov. 2011 to Apr. 2012, 50 patients were recruited for thyroid surgery in the Sun Yat-sen University Cancer Centre. During surgery, fine-needle aspiration of suspected tissues, including parathyroid gland, thyroid gland, muscle, fat tissue, and lymph node, was performed, the PTH levels were measured. In addition, the tissues above-mentioned were taken to pathological examination. Statistical processing was adopted to determine the sensitivity and specificity of intraoperative fine-needle aspiration with measurement of PTH level in finding the pathology of the parathyroid gland. RESULTS: There were 237 tissues from 50 patients in total, and 45 of them were certified as the parathyroid glands by pathology. Intra-operative PTH (ioPTH) of the tissues in forty-four cases were higher than 600 ng/L, ioPTH of the tissues in one case was lower than 600 ng/L, and it was 160 ng/L. The highest ioPTH in other cases was 537.7 ng/L. The sensitivity was 97.8%. The specificity was 100%. The difference between the sensitivity and the specificity of two groups was not statistically significant, and P > 0.05. The level of PTH of parathyroid gland were much higher than other tissues, and P < 0.001. CONCLUSIONS: The level of ioPTH of parathyroid gland were far higher than thyroid, muscle, fat, lymph node. It is an economic, fast and less traumatic way to identify the parathyroid gland by using the fine-needle aspiration of the parathyroid tissue with measurement of PTH levels. The sensitivity and the specificity are high. It can be used in the thyroidectomy to identify the parathyroid glands.