Increased expression of the microRNA 106b~25 cluster and its host gene MCM7 in corticotroph pituitary adenomas is associated with tumor invasion and Crooke's cell morphology

Aggressive PitNETs and Potential Target Therapies: A Systematic Review of Molecular and Genetic Pathways

Recently, advances in molecular biology and bioinformatics have allowed a more thorough understanding of tumorigenesis in aggressive PitNETs (pituitary neuroendocrine tumors) through the identification of specific essential genes, crucial molecular pathways, regulators, and effects of the tumoral microenvironment. Target therapies have been developed to cure oncology patients refractory to traditional treatments, introducing the concept of precision medicine. Preliminary data on PitNETs are derived from preclinical studies conducted on cell cultures, animal models, and a few case reports or small case series. This study comprehensively reviews the principal pathways involved in aggressive PitNETs, describing the potential target therapies. A search was conducted on Pubmed, Scopus, and Web of Science for English papers published between 1 January 2004, and 15 June 2023. 254 were selected, and the topics related to aggressive PitNETs were recorded and discussed in detail: epigenetic aspects, membrane proteins and receptors, metalloprotease, molecular pathways, PPRK, and the immune microenvironment. A comprehensive comprehension of the molecular mechanisms linked to PitNETs' aggressiveness and invasiveness is crucial. Despite promising preliminary findings, additional research and clinical trials are necessary to confirm the indications and effectiveness of target therapies for PitNETs.

Pathology of Crooke Cells in the Human Pituitaries: A Timely Review

Crooke cell change was first found in the regressed and suppressed corticotroph (adrenocorticotropic hormone-producing) cells, and now is known to occur in pituitary tumors. The tumor cells of this type can be recognized by morphology with immunohistochemistry, and are well known to predict aggressive behavior such as invasion and rare metastases. This is one of the representative neuroendocrine tumors in the pituitary which is now considered to have malignant potential as proposed in the pancreas and gastrointestinal tracts. It is important to emphasize the pituitary tumor pathology such as Crooke cell change for prognostication and appropriate therapies. This review article describes the evolution from the Crooke cells to Crooke cell tumors which is timely along with the Fifth WHO classification 2022 published online.

Non-coding RNAs and exosomal non-coding RNAs in pituitary adenoma

Pituitary adenoma (PA) is the third most common primary intracranial tumor in terms of overall disease incidence. Although they are benign tumors, they can have a variety of clinical symptoms, but are mostly asymptomatic, which often leads to diagnosis at an advanced stage when surgical intervention is ineffective. Earlier identification of PA could reduce morbidity and allow better clinical management of the affected patients. Non-coding RNAs (ncRNAs) do not generally code for proteins, but can modulate biological processes at the post-transcriptional level through a variety of molecular mechanisms. An increased number of ncRNA expression profiles have been found in PAs. Therefore, understanding the expression patterns of different ncRNAs could be a promising method for developing non-invasive biomarkers. This review summarizes the expression patterns of dysregulated ncRNAs (microRNAs, long non-coding RNAs, and circular RNAs) involved in PA, which could one day serve as innovative biomarkers or therapeutic targets for the treatment of this neoplasia. We also discuss the potential molecular pathways by which the dysregulated ncRNAs could cause PA and affect its progression.

circDYRK1A tethers biological behaviors of gastric carcinoma using novel bioinformatics analysis and experimental validations

Gastric cancer has been one of the wide public health burdens with its high morbidity and mortality over several decades. As the unconventional modules among RNA families, circular RNAs present their blazing biological effects during gastric carcinogenesis. Though diverse hypothetical mechanisms were reported, further tests were necessitated for authentication. Herein, this study pinpointed a representative circDYRK1A which screened from vast amounts of public data sets using surprisingly novel bioinformatics approaches together with validations from the in vitro findings and then concluded that circDYRK1A tethered the biological behavior and swayed the clinicopathological features with gastric cancer patients thus providing an in-depth awareness for gastric carcinoma.

Prevalence and clinical characteristics of Crooke's cell adenomas in 101 patients with T-PIT-positive pituitary adenomas: Case series and literature review

PURPOSE

We aimed to perform a retrospective analysis of a rare subtype of corticotroph adenoma, Crooke's cell adenoma, to better understand its clinical features.

METHODS

We collected T-PIT-positive pituitary adenomas and screened Crooke's cell adenomas from January 2020 to December 2021 in our center. Case reports of such tumors were also collected through a literature search. Clinical data such as biochemical tests, imaging examinations, and pathological data of the above cases were analyzed.

RESULTS

A total of 101 T-PIT-positive patients were treated in our center in the last 2 years, and 4 were finally pathologically diagnosed with Crooke's cell adenomas. All of these patients were male with elevated adrenocorticotropic hormone levels, and 50.0% presented with hypercortisolemia, Cushing's syndrome, visual impairment, and headache. The tumor diameter was significantly larger in these 4 patients (37.0 mm) than in the other patients (26.0 mm), and their tumor invasive behavior was more pronounced. Cases reported in the literature were mainly female (72.8%), and the clinical presentation was also dominated by Cushing's syndrome (65.1%) and hormonal dysfunction. Tumors were more common as macroadenomas (33.2 mm) and suprasellar growths (63.8%). The tumor recurrence rate was as high as 55.6%, with 6 cases progressing to pituitary carcinomas and 7.7% of tumor-related deaths. Our further integrated analysis of our center and reported cases revealed that gender, Cushing's syndrome, visual dysfunction, hormonal disorders, and tumor growth characteristics were statistically different in different tumor categories.

CONCLUSION

Crooke's cell adenoma is a tumor subtype with obvious clinical aggressive behavior, and an in-depth analysis of its clinical characteristics may assist in developing a comprehensive treatment plan.

Functioning Crooke Cell Adenomas: Case Series and Literature Review

BACKGROUND

Crooke cell adenomas (CCA) are rare potentially aggressive pituitary adenomas. Data regarding prevalence and clinical course is sparse.

METHODS

Methods consisted of a retrospective review of 59 consecutive functioning corticotroph adenomas (FCA) operated between October 2017-November 2020, and a literature review of CCA publications since 1991.

RESULTS

The prevalence of CCA among FCA at our institution was 8.5% (5/59). In the 4 other surgical cases series, prevalence of CCA ranged between 0%-6.8%. Our patients, 4 women and 1 man, mean age 46±11 years, presented with hypercortisolism (3/5), vision loss (1/5) and incidentally (1/5). All patients had elevated ACTH (151±54 pg/ml) and urinary free cortisol (830±796.5 μg/day) levels. Radiologically, 3 tumors were macroadenomas and 2 had cavernous sinus invasion. All patients achieved biochemical remission at 3 months postoperatively. One patient with a giant pituitary adenoma underwent fractionated radiation for residual tumor. During follow-up (range: 3.1-31.0 months), no patients had evidence of radiological or biochemical recurrence. The literature review (3 case series) and 21 case reports identified 22 FCA with outcome data. Additional treatments included reoperation (50%), radiation (59%), bilateral adrenalectomy (23%) and Temozolomide (36%).

CONCLUSION

We report a higher CCA prevalence among functioning ACTH-adenomas after the implementation of 2017 WHO classification. In our series and the literature, most CCAs were macroadenomas with high ACTH levels. Postoperative outcomes were excellent in our series, while some cases from the literature were refractory to standard treatments. Larger clinical and molecular studies are needed to identify patients at risk.

[Differences in plasma miRNA levels in inferior petrosal sinus samples of patients with ACTH-dependent Cushing's syndrome]

BACKGROUND

For the last decades microRNAs (miR) have proven themselves as novel biomarkers for various types of diseases. Identification of specific circulating microRNA panel that differ patient with Cushing's disease (CD) and ectopic ACTH syndrome (EAS) could improve the diagnostic procedure.

AIM

to evaluate the differences in miR levels in plasma samples drained from inferior petrosal sinuses in patients with CD and EAS.

MATERIALS AND METHODS

single-center, case-control study: we enrolled 24 patients with ACTH-dependent Cushing's syndrome (CS) requiring bilateral inferior petrosal sinus sampling (BIPSS).  Among them 12 subjects were confirmed as CD (males=2, females=10; median age 46,5 [IR 33,8;53,5]) and 12 as EAS (males=4, females=8, median age 54 [IR 38,75;60,75]). BIPSS was performed through a percutaneous bilateral approach. Once catheters were properly placed, blood samples were withdrawn simultaneously from each petrosal sinus and a peripheral vein. Plasma samples from both sinuses were centrifuged and then stored at -80 C. MiRNA isolation from plasma was carried out by an miRneasy Plasma/Serum Kit (Qiagen, Germany) on the automatic QIAcube station according to the manufacturer protocol. To prevent degradation, we added 1 unit of RiboLock Rnase Inhibitor (Thermo Fisher Scientific, USA) per 1 μL of RNA solution. The concentration of total RNA in the aqueous solution was evaluated on a NanoVue Plus spectrophotometer (GE Healthcare, USA). The libraries were prepared by the QIAseq miRNA Library Kit following the manufacturer standard protocols. MiR expression was then analyzed by sequencing on Illumina NextSeq 500 (Illumina, USA).

RESULTS

108 miRNAs were differently expressed (p <0,05) in inferior petrosal sinus samples of patients with CD vs EAS. We divided these miRNAs into 3 groups based on the significance of the results. The first group consisted of samples with the highest levels of detected miR in both groups. Four miRNAs were included: miR-1203 was downregulated in CD vs EAS - 36.74 (p=0,013), and three other were upregulated in CD vs EAS: miR-383-3p 46.36 (p=0,01), miR-4290 6.84 (p=0,036), miR-6717-5p 4.49 (p=0,031). This miRs will be validated in larger cohorts using RT-qPCR.

CONCLUSION

Plasma miR levels differ in inferior petrosal samples taken from patients with CD vs EAS. These miRs need to be validated by different methods and in peripheral plasma samples in order to be used as potentially non-invasive biomarkers to differentiate ACTH-dependent CS.

MiR-106b-5p Promotes Malignant Behaviors of Cervical Squamous Cell Carcinoma Cells by Targeting TIMP2

The objective of this study was to investigate modulatory mechanism of miR-106b-5p and tissue inhibitor of metalloproteinases 2 (TIMP2) on cervical squamous cell carcinoma cells. Differentially expressed genes in CSCC were analyzed via bioinformatics analysis. The targeting impact of miR-106b-5p on TIMP2 was validated through dual-luciferase assay and RNA immunoprecipitation assay. MiR-106b-5p level and TIMP2 mRNA level were assessed via qRT-PCR. TIMP2 protein level was measured via western blot. Malignant behaviors of CSCC cells were evaluated by functional experiments. The EMT and apoptosis-related proteins were determined via western blot. MiR-106b-5p was noticeably elevated in CSCC cells. Its downstream target was TIMP2. MiR-106b-5p and TIMP2 levels were inversely correlated. MiR-106b-5p overexpression fostered malignant phenotypes of CSCC cells, and vice versus. TIMP2 overexpression weakened the promotive impact of forced expression of miR-106b-5p on CSCC cell growth. EMT was facilitated by forced expression of miR-106b-5p. MiR-106b-5p regulates the progression of CSCC cells via targeting TIMP2, which may provide novel value for development of therapeutic targets for CSCC.

IL-6 promotes PD-L1 expression in monocytes and macrophages by decreasing protein tyrosine phosphatase receptor type O expression in human hepatocellular carcinoma

Background

We have previously discovered a relationship between the low expression of protein tyrosine phosphatase, receptor type O (PTPRO) in tumor-infiltrating T cells and immunosuppression. The aim of the present study was to investigate the relationship between decreased PTPRO and increased programmed death ligand 1 (PD-L1) in both the peripheral monocytes and tumor-infiltrating macrophages of human hepatocellular carcinoma (HCC).

Methods

The expression and correlation of all the indices were explored in monocytes and tumor-infiltrating macrophages within both human and mice HCC. The mechanic regulations were studied by using both in vitro and in vivo studies.

Results

We found a significant decrease in PTPRO in HCC peripheral monocytes that was associated with increased PD-L1 expression in peripheral monocytes and tumor-associated macrophages (TAMs) in HCC. Monocyte PD-L1 and PTPRO therefore could serve as valuable prognostic indicators for post-surgery patients with HCC and were associated with increased T-cell exhaustion (Tim3+T cells). A depletion of PTPRO promoted PD-L1 secretion in both monocytes and macrophages through the JAK2/STAT1 and JAK2/STAT3/c-MYC pathways. Increased IL-6 expression was associated with activation of JAK2/STAT3/c-MYC and with decreased PTPRO expression through the STAT3/c-MYC/miR-25–3 p axis. Monocytes and TAMs showed significantly increased miR-25–3 p expression, which could target the 3′ untranslated region of PTPRO. The miR-25–3 p expression positively correlated with serum IL-6 levels, but inversely correlated with PTPRO in HCC monocytes. IL-6/STAT3/c-MYC activation enhanced in vitro miR-25–3 p transcription and decreased PTPRO, while further promoting PD-L1 secretion. Adoptive cell transfer of c-MYC/miR-25–3 p–modified monocytes promoted tumor growth by downregulating PTPRO and causing a PD-L1–induced immunosuppression in an orthotopic tumor transplantation model.

Conclusions

Increased serum IL-6 downregulated PTPRO expression in HCC monocytes and macrophages by activating STAT3/c-MYC/miR-25–3 p and by further enhancing PD-L1 expression through JAK2/STAT1 and JAK2/STAT3/c-MYC signaling.

Clinical, Biological, Radiological Pathological and Immediate Post-Operative Remission of Sparsely and Densely Granulated Corticotroph Pituitary Tumors: A Retrospective Study of a Cohort of 277 Patients With Cushing's Disease

PURPOSE

Cushing's disease is the most common cause of endogenous hypercortisolemia due to a corticotroph pituitary tumor. Up-to-date there is no reliable biomarker of invasiveness among corticotroph tumors, while it is well established in the literature that sparsely granulated somatotroph tumors are characterized by poorer prognosis. The aim of the study was to correlate multiple data including clinical, biochemical, radiological, and pathological findings (including granulation pattern) as well as immediate post-operative remission status among patients operated on due to corticotroph tumors.

METHODS

We enrolled all patients consecutively operated on for planned transsphenoidal neurosurgery due to corticotroph PitNETs in years 2010-2018. We excluded from analysis silent corticotroph tumors, plurihormonal PitNETs, and the Crooke's cell adenomas.

RESULTS

We recorded 348 hormonally active corticotroph PitNETs. The results of the analysis showed the female predominance 79.88% (n = 278), with the mean age of Cushing's disease occurrence 43.27 years of age. The mean time from the first signs and symptoms to the operation was 2 years. The women were diagnosed earlier (20-40 years of age vs. 50-60 years of age among men). We performed a detailed analysis of 277 cases classified by granularity pattern as DG or SG corticotroph PitNETs. Densely granulated tumors (DG) occurred four times more frequently than sparsely granulated (SG) (n = 225 vs. n = 52), at similar age (mean 42.94; median 40 vs. mean 45.46; median 45.5; p = 0.3896), but were characterized by lower Knosp's scale grades (p = 0.0147*), smaller preoperative tumors' volumes measured at MRI, and more commonly exhibited lower Ki-67 labeling index (<3%) (p = 0.0168*). What is more, DG adenomas more frequently achieved an immediate remission status (measured as postoperative cortisol concentration <2 µg/dl; p = 0.0180*), and the mean postoperative cortisol concentration in DG group was lower than in SG group (mean 5.375 µg/dl vs. 10.47 µg/dl; median 2.49 µg/dl vs. 6.52 µg/dl; p = 0.0028**).

CONCLUSIONS

Our study indicates that DG corticotroph adenomas occurred at younger age, more commonly were microadenomas as compared to SG tumors, less frequently had invasive features in comparison to SG corticotroph adenomas (p = 0.0019**), and more commonly achieved an immediate postsurgical hormonal remission (p = 0.0180*). We highlight the need for an accurate differentiation of DG and SG subtypes in the pathomorphological diagnosis of corticotropic tumors, especially in invasive PitNETs.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

Recent Understanding and Future Directions of Recurrent Corticotroph Tumors

Corticotroph tumors (CTs) are pituitary neoplasms arising from the Tpit lineage, which may or not express adrenocorticotrophic hormone (ACTH). Functioning CTs cause Cushing's disease (CD), which has high morbidity and mortality due to hypercortisolemia. "Non-functioning" or silent CTs (SCT) and the Crooke's cell subtypes do not cause CD and may be asymptomatic until manifested by compressive symptoms and are more frequently found as macroadenoma. Both tend toward more aggressive behavior, recurrence, and a higher rate of malignant transformation to pituitary carcinoma. Tumorigenesis involves genetic, epigenetic, and post-transcriptional disruption of cell-cycle regulators, which increase cell proliferation, POMC overexpression, ACTH transcription, and/or hypersecretion. Furthermore, functioning CTs develop resistance to glucocorticoid-mediated negative feedback on ACTH secretion, through increased expression of testicular orphan nuclear receptor 4 (TR4), heat-shock protein 90 (HSP90), and loss-of-function mutation of CDK5 and ABL enzyme substrate 1 (CABLES1) gene. Overt autonomous hypercortisolemia is difficult to control, and multiple diagnostic studies and therapeutic modalities are commonly required. Cell-cycle regulation depends mainly on p27, cyclin E, cyclin-dependent kinases (CDKs), and the retinoblastoma protein (Rb)/E2F1 transcription factor complex. Gain-of-function mutations of ubiquitin-specific protease (USP) 8, USP48, and BRAF genes may subsequently cause overexpression of epithelial growth factor receptor (EGFR), and enhance POMC transcription, cell proliferation, and tumor growth. Epigenetic changes through micro RNAs and decreased DNA deacetylation by histone deacetylase type 2 (HDAC2), may also affect tumor growth. All the former mechanisms may become interesting therapeutic targets for CTs, aside from temozolomide, currently used for aggressive tumors. Potential therapeutic agents are EGFR inhibitors such as gefitinib and lapatinib, the purine analog R-roscovitine by dissociation of CDK2/Cyclin E complex, the HSP90 inhibitor silibinin (novobiocin), to reduce resistance to glucocorticoid-mediated negative feedback, and BRAF inhibitors vemurafenib and dabrafenib in BRAF V600E positive tumors. This review summarizes the molecular mechanisms related to CTs tumorigenesis, their diagnostic approach, and provides an update of the potential novel therapies, from the lab bench to the clinical translation.

Identification of Serum microRNA-25 as a novel biomarker for pancreatic cancer

To identify serum microRNA-25 (miR-25) as a diagnostic biomarker for pancreatic cancer (PCa) and to evaluate its supplementary role with serum carbohydrate antigen 19-9 (CA19-9) in early identification of cancers.Eighty patients with pancreatic cancer and 91 non-cancer controls were enrolled in this study. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression level of miR-25. Levels of CA19-9, carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125) were measured by chemiluminescent immunoassay. The logistic model was established to evaluate the correlation of miR-25 with clinical characteristics. A risk model for PCa was conducted by R statistical software. Diagnostic utility for PCa and correlation with clinical characteristics were analyzed.The expression level of miR-25, in the PCa group was significantly higher (P < .05). Risk Model illustrated the relation between miR-25 and pancreatic cancer. With the combination of CA19-9, the performance of miR-25 in early stages (I+II) in the diagnosis of PCa was profoundly better than CA19-9 and miR-25 alone. This combination was more effective for discriminating PCa from non-cancer controls (AUC-ROC, 0.985; sensitivity, 97.50%; specificity, 90.11%) compared with CA19-9 alone or the combination of CA19-9 and CA125.The expression level of miR-25 among pancreatic cancer patients was significantly higher than that in the control group. miR-25 existed as one of the most relevant factors of PCa. miR-25 can serve as a novel noninvasive approach for PCa diagnosis, and with the supplementary of CA19-9, the combination was more effective, especially in early tumor screening.

Novel Insights into Pituitary Tumorigenesis: Genetic and Epigenetic Mechanisms

Substantial advances have been made recently in the pathobiology of pituitary tumors. Similar to many other endocrine tumors, over the last few years we have recognized the role of germline and somatic mutations in a number of syndromic or nonsyndromic conditions with pituitary tumor predisposition. These include the identification of novel germline variants in patients with familial or simplex pituitary tumors and establishment of novel somatic variants identified through next generation sequencing. Advanced techniques have allowed the exploration of epigenetic mechanisms mediated through DNA methylation, histone modifications and noncoding RNAs, such as microRNA, long noncoding RNAs and circular RNAs. These mechanisms can influence tumor formation, growth, and invasion. While genetic and epigenetic mechanisms often disrupt similar pathways, such as cell cycle regulation, in pituitary tumors there is little overlap between genes altered by germline, somatic, and epigenetic mechanisms. The interplay between these complex mechanisms driving tumorigenesis are best studied in the emerging multiomics studies. Here, we summarize insights from the recent developments in the regulation of pituitary tumorigenesis.

Multiple Endocrine Neoplasia Type 1: The Potential Role of microRNAs in the Management of the Syndrome

Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited tumor syndrome, characterized by the development of multiple neuroendocrine tumors (NETs) in a single patient. Major manifestations include primary hyperparathyroidism, gastro-entero-pancreatic neuroendocrine tumors, and pituitary adenomas. In addition to these main NETs, various combinations of more than 20 endocrine and non-endocrine tumors have been described in MEN1 patients. Despite advances in diagnostic techniques and treatment options, which are generally similar to those of sporadic tumors, patients with MEN1 have a poor life expectancy, and the need for targeted therapies is strongly felt. MEN1 is caused by germline heterozygous inactivating mutations of the MEN1 gene, which encodes menin, a tumor suppressor protein. The lack of a direct genotype–phenotype correlation does not permit the determination of the exact clinical course of the syndrome. One of the possible causes of this lack of association could be ascribed to epigenetic factors, including microRNAs (miRNAs), single-stranded non-coding small RNAs that negatively regulate post-transcriptional gene expression. Some miRNAs, and their deregulation, have been associated with MEN1 tumorigenesis. Recently, an extracellular class of miRNAs has also been identified (c-miRNAs); variations in their levels showed association with various human diseases, including tumors. The aim of this review is to provide a general overview on the involvement of miRNAs in MEN1 tumor development, to be used as possible targets for novel molecular therapies. The potential role of c-miRNAs as future non-invasive diagnostic and prognostic biomarkers of MEN1 will be discussed as well.

Differential Expression of MicroRNAs in Silent and Functioning Corticotroph Tumors

The potential role of miRNAs in the silencing mechanisms of pituitary neuroendocrine tumors (PitNETs) has not been addressed. The aim of the present study was to evaluate the expression levels and the potential associated role of some miRNAs, pathways, and transcription factors in the silencing mechanisms of corticotroph tumors (CTs). Accordingly, the expression of miR-375, miR-383, miR-488, miR-200a and miR-103; of PKA, MAP3K8, MEK, MAPK3, NGFIB, NURR1, PITX1, and STAT3 were analyzed via qRT-PCR in 23 silent and 24 functioning CTs. miR-200a and miR-103 showed significantly higher expression in silent than in functioning CTs, even after eliminating the bias of tumor size, therefore enabling the differentiation between the two variants. Additionally, miR-383 correlated negatively with TBX19 in silent CTs, a transcription factor related with the processing of POMC that can participate in the silencing mechanisms of CTs. Finally, the gene expression levels of miR-488, miR-200a, and miR-103 were significantly higher in macroadenomas (functioning and silent) than in microadenomas. The evidence from this study indicates that miRNAs could be involved in the pathophysiology of CTs. The translational implications of these findings suggest that pharmacological treatments specifically targeting these miRNAs could become a promising therapeutic option for these patients.

Biomarkers for Liquid Biopsies of Pituitary Neuroendocrine Tumors

Pituitary neuroendocrine tumors (PitNET) do not only belong to the most common intracranial neoplasms but seem to be generally more common than has been thought. Minimally invasive liquid biopsies have the potential to improve their early screening efficiency as well as monitor prognosis by facilitating the diagnostic procedures. This review aims to assess the potential of using liquid biopsies of different kinds of biomarker species that have only been obtained from solid pituitary tissues so far. Numerous molecules have been associated with the development of a PitNET, suggesting that it often develops from the cumulative effects of many smaller genetic or epigenetic changes. These minor changes eventually pile up to switch critical molecules into tumor-promoting states, which may be the key regulatory nodes representing the most potent marker substances for a diagnostic test. Drugs targeting these nodes may be superior for the therapeutic outcome and therefore the identification of such pituitary-specific cellular key nodes will help to accelerate their application in medicine. The ongoing genetic degeneration in pituitary adenomas suggests that repeated tumor profiling via liquid biopsies will be necessary for personalized and effective treatment solutions.

Aggressive Pituitary Tumor with Crooke's Cells and Invasion of the Posterior Fossa

BACKGROUND

Pituitary adenomas are mostly benign in character and are managed via a transsphenoidal approach in most cases. Crooke's cell adenoma (CCA) is a particular variant accounting for less than 1% of the pituitary adenomas. They have a distinctive histopathologic pattern and behavior.

CASE DESCRIPTION

We present a case of a 56-year-old man with recurrent pituitary adenoma and complicated neurosurgical history. Imaging follow-up showed a suprasellar mass with progressive growth into the posterior fossa. Surgical management via retrosigmoid craniectomy was performed, and histopathology elucidated Crooke's cells.

CONCLUSIONS

CCA is recognized by its local aggressiveness and high recurrence rates. They tend to be locally invasive; however, posterior fossa invasion has not been reported to date. We aim to contribute to the arsenal of differential diagnosis of similar pituitary tumor cases.

Pan-cancer analysis reveals cooperativity of both strands of microRNA that regulate tumorigenesis and patient survival

Recently, both 5p and 3p miRNA strands are being recognized as functional instead of only one, leaving many miRNA strands uninvestigated. To determine whether both miRNA strands, which have different mRNA-targeting sequences, cooperate to regulate pathways/functions across cancer types, we evaluate genomic, epigenetic, and molecular profiles of >5200 patient samples from 14 different cancers, and RNA interference and CRISPR screens in 290 cancer cell lines. We identify concordantly dysregulated miRNA 5p/3p pairs that coordinately modulate oncogenic pathways and/or cell survival/growth across cancers. Down-regulation of both strands of miR-30a and miR-145 recurrently increased cell cycle pathway genes and significantly reduced patient survival in multiple cancers. Forced expression of all four strands show cooperativity, reducing cell cycle pathways and inhibiting lung cancer cell proliferation and migration. Therefore, we identify miRNA whose 5p/3p strands function together to regulate core tumorigenic processes/pathways and reveal a previously unknown pan-cancer miRNA signature with patient prognostic power.

5p and 3p miRNA strands have different mRNA-targeting sequences and may both functionally impact gene expression in cancer. Here, the authors undertake a pan-cancer analysis that indicates 5p/3p miRNA strands function together to regulate tumorigenic processes.

Long noncoding RNA HOXA-AS2 mediates microRNA-106b-5p to repress sepsis-engendered acute kidney injury

HOXA cluster antisense RNA 2 (HOXA-AS2) is a long noncoding RNA associated with the development of numerous cancers. But, whether HOXA-AS2 exhibits a certain function in sepsis-engendered acute kidney injury (AKI) remains uninvestigated. We strived to unveil the role of HOXA-AS2 in sepsis-engendered AKI. The expression of HOXA-AS2 in sepsis patients, animal models and lipopolysaccharide (LPS)-impaired HK-2 cells was primarily assessed via a real-time quantitative polymerase chain reaction. The effects of HOXA-AS2 on cell survival of HK-2 cells under LPS irritation were evaluated after overexpression of HOXA-AS2. The correlation between HOXA-AS2 and microRNA (miR)-106b-5p was forecasted via bioinformatics software and verified by using a luciferase report system. Subsequently, the functions of miR-106b-5p in LPS-damaged HK-2 cells were reassessed. Western blot was used for the determination of Wnt/β-catenin and nuclear factor-κB (NF-κB) pathways. HOXA-AS2 expression was decreased in sepsis patients, animal operation group and LPS-irritated HK-2 cells. Overexpressed HOXA-AS2 mollified LPS-triggered impairment in HK-2 cells. In addition, a negative mediatory relation between HOXA-AS2 and miR-106b-5p was predicated. Synchronously, overexpressed miR-106b-5p counteracted the protection of HOXA-AS2 in LPS-damaged HK-2 cells. Ultimately, Wnt/β-catenin and NF-κB pathways were hindered by HOXA-AS2 via targeting miR-106b-5p. HOXA-AS2 exhibited protection in sepsis-engendered AKI via targeting miR-106b-5p and hindering the Wnt/β-catenin and NF-κB pathways.

MiR-219a-2-3p suppresses cell proliferation and promotes apoptosis by targeting MDM2/p53 in pituitary adenomas cells

Pituitary adenomas constitute one of the most common intracranial tumors. MicroRNAs play an important role in development and progression of pituitary adenomas. In this study, we showed that miR-219a-2-3p was significantly down-regulated in pituitary adenomas cells. Overexpression of miR-219a-2-3p suppressed the proliferation and promoted apoptosis of pituitary adenomas cells. After bioinformatics analysis, we found that MDM2 was one of the downstream targets of miR-219a-2-3p. Further researches showed that miR-219a-2-3p could reduce the protein level of MDM2 by binding to the 3'-UTR of MDM2 and promoted p53 expression. Then, we overexpressed both miR-219a-2-3p and MDM2 in the same group and found that it could counteract the effect of overexpressing miR-219a-2-3p alone on proliferation and apoptosis of pituitary adenoma cells. Taken together, these results suggested that miR-219a-2-3p regulated the proliferation and apoptosis by targeting MDM2/p53 in pituitary adenomas. Therefore, miR-219a-2-3p may serve as a novel marker and therapeutic target for pituitary adenomas.

Genetics of Pituitary Tumours

Pituitary tumours are relatively common in the general population. Most often they occur sporadically, with somatic mutations accounting for a significant minority of somatotroph and corticotroph adenomas. Pituitary tumours can also develop secondary to germline mutations as part of a complex syndrome or as familial isolated pituitary adenomas. Tumours occurring in a familial setting may present at a younger age and can behave more aggressively with resistance to treatment. This chapter will focus on the genetics and molecular pathogenesis of pituitary tumours.

LncRNA XIST depletion prevents cancer progression in invasive pituitary neuroendocrine tumor by inhibiting bFGF via upregulation of microRNA-424-5p

Background

Long noncoding RNAs (lncRNAs) are vital mediators in human cancers including pituitary neuroendocrine tumor (PitNET) and could function as competing endogenous RNAs (ceRNAs) of microRNAs (miRNAs). The main objective of this study is to identify effect of lncRNA X-inactive specific transcript (XIST) and microRNA-424-5p (miR-424-5p) on PitNET.

Methods

Microarray analysis was employed to identify the PitNET-related differentially expressed lncRNAs. PitNET tissues, including both invasive and non-invasive subtypes in parallel with normal pituitary tissues were collected for the determination of the expression of XIST, miR-424-5p and basic fibroblast growth factor (bFGF) and the interaction among them. Subsequently, the expression of XIST, miR-424-5p and bFGF in PitNET cells was altered to elucidate their biological significance in the aspects of proliferation, migration, invasion, and the apoptosis.

Results

Both XIST and bFGF exhibited high expression, but miR-424-5p had a low expression in invasive PitNET tissues as compared to non-invasive PitNET normal pituitary tissues. Additionally, XIST competitively bound to miR-424-5p to elevate the expression of bFGF. Furthermore, depleted XIST or bFGF, or elevated miR-424-5p was revealed to suppress the proliferation, migration, invasion, and promote cell cycle arrest and apoptosis of invasive PitNET cells. miR-424-5p repressed the proliferation, migration, invasion of invasive PitNET cells by targeting bFGF.

Conclusion

In conclusion, the fundamental findings of the present study suggested that the functional suppression of XIST downregulated bFGF to inhibit the development of PitNET by increasing miR-424-5p expression, proposing XIST as a novel therapeutic target for PitNET.

Lineage-dependent role of miR-410-3p as oncomiR in gonadotroph and corticotroph pituitary adenomas or tumor suppressor miR in somatotroph adenomas via MAPK, PTEN/AKT, and STAT3 signaling pathways

PURPOSE

miR-410-3p plays opposite roles in different cancers and may act as an oncomiR or tumor suppressor miR. The purpose of this study was to assess the role of miR-410-3p in somatotroph, gonadotroph, and corticotroph pituitary adenomas.

METHODS

Tissue samples were obtained from 75 patients with pituitary adenoma. miR-410-3p expression was assessed using qRT-PCR performed on RNA isolated from fresh frozen samples. In vitro experiments were performed on cell lines derived from somatotroph (GH3), gonadotroph (RC-4B/C), and corticotroph (AtT-20) pituitary tumors. Cells were transfected with synthetic mimic of miR-410-3p or non-targeting scrambled-miR control. Subsequently, proliferation assays and transwell invasion assays were performed. The expression of cyclin D1, E1, and B1 in cells after transfection was determined using qRT-PCR. The activation of MAPK, PTEN/AKT and STAT3 signaling pathways were assessed using western blot.

RESULTS

We have found that the level of expression of miR-410-3p differs in particular types of pituitary adenomas. miR-410-3p significantly upregulates proliferation and invasiveness of RC-4B/C and AtT-20 cells, while inhibiting GH3 cells. We observed that the levels of cyclin B1 upon transfection with miR-410-3p mimic were increased in RC-4B/C and AtT-20, yet decreased in GH3 cells. We have shown that miR-410-3p promoted the activation of MAPK, PTEN/AKT, and STAT3 signaling pathways in RC-4B/C and AtT-20 cells, but suppressed their activity in GH3 cells.

CONCLUSIONS

miR-410-3p acts as an oncomiR in gonadotroph and corticotroph adenoma cells, while as a tumor suppressor miR in somatotroph adenoma cells.

Molecular Biology of Pituitary Adenomas

Pituitary adenomas are benign tumors, but still cause significant morbidity and in some cases increases in mortality. Surgical resection is not without risks, and approximately 40% of adenomas are incompletely resected. Medical therapies such as dopamine agonists, somatostatin analogues, and growth hormone antagonists are associated with numerous side effects. Understanding the molecular biology of pituitary adenomas may yield new therapeutic approaches. Additional studies are needed to help determine which genes or pathways are "drivers" of tumorigenesis and should be therapeutic targets. Further studies may also enable pituitary adenoma stratification to tailor treatment approaches.

Aberrant ERG expression associates with downregulation of miR-4638-5p and selected genomic alterations in a subset of diffuse large B-cell lymphoma

ERG (avian v-ets erythroblastosis virus E26 oncogene homolog), an oncoprotein in prostate carcinoma and Ewing's sarcoma is associated with poor prognosis in patients with acute myeloid leukemia and T lymphoblastic leukemia. However little is known about ERG in lymphoma. Here we studied ERG in diffuse large B-cell lymphoma (DLBCL) by immunohistochemistry, fluorescence in situ hybridization (FISH), genome-wide microRNA (miRNA) expression profiling, real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and whole exome sequencing (WES). Approximately 30% of de novo DLBCLs (37 of 118) expressed ERG (ERG+). ERG expression showed no significant correlation with DLBCL cell-of-origin classification, patient's age, sex, nodal, or extranodal disease status, tumor expression of p53 or p63. There was no ERG rearrangement in 10 randomly selected ERG+ DLBCLs by FISH. Forty-three miRNAs showed significant differential expression between ERG+ and ERG- DLBCLs. Downregulation of miR-4638-5p was confirmed by real-time RT-PCR. WES not only confirmed known gene mutations in DLBCLs but also revealed multiple novel gene mutations in POLA1, E2F1, PSMD8, AXIN1, GAB2, and GNB2L1, which occur more frequently in ERG+ DLBCLs. In conclusion, our studies demonstrated aberrant ERG expression in a subset of DLBCL, which is associated with downregulation of miR-4638-5p. In comparison with ERG-negative DLBCL, ERG+ DLBCL more likely harbors mutations in genes important in cell cycle control, B-cell receptor-mediated signaling and degradation of β-catenin. Further clinicopathological correlation and functional studies of ERG-related miRNAs and pathways may provide new insight into the pathogenesis of DLBCL and reveal novel targets for better management of patients with DLBCL.

MicroRNAs in endocrine tumors

MicroRNAs (miRNAs) are small, protein noncoding RNAs that regulate gene expression post-transcriptionally. Their role is considered to set the gene expression to the optimal level, or in other words to provide "fine tuning" of gene expression. They regulate essential physiological processes such as differentiation, cell growth, apoptosis and their role is known in tumor development too. At tissue level differential miRNA expression in endocrine disorders including endocrine malignancies has also been reported. A new era of miRNAs-related research started when miRNAs were successfully detected outside of cells, in biofluids, in cell-free environments. Their significant role has been demonstrated in cell-cell communication in tumor biology. Due to their stability circulating miRNAs can serve as potential biomarkers. In common diseases circulating miRNAs can be potentially proposed as screening biomarkers and they are also useful to detect tumor recurrence hence they can be applied in post-surgery follow-up too. MiRNAs as diagnostic markers can also be helpful at tissue level when certain histology diagnosis is challenging. Beside diagnosis, tissue miRNAs have the potential to predict prognosis. Intensive research is carried out regarding endocrine tumors as well in terms of miRNAs. However, until now miRNAs as biomarkers do not applied in routine diagnostics, probably due to the challenging preanalytics. In this review we summarized tissue and circulating miRNAs found in thyroid, adrenal, pituitary and neuroendocrine tumors. We aimed to highlight the most important, selected miRNAs with potential diagnostic and prognostic value both in tissue and circulation. Common miRNAs across different endocrine neoplasms are summarized and miRNAs enriched at 14q31 locus are also highlighted suggesting their general role in tumorigenesis of endocrine glands.

Molecular Network Basis of Invasive Pituitary Adenoma: A Review

Cases with pituitary adenoma comprise 10-25% of intracranial neoplasm, being the third most common intracranial tumor, most of the adenomas are considered to be benign. About 35% of pituitary adenomas are invasive. This review summarized the known molecular basis of the invasiveness of pituitary adenomas. The study pointed out that hypoxia-inducible factor-1α, pituitary tumor transforming gene, vascular endothelial growth factor, fibroblast growth factor-2, and matrix metalloproteinases (MMPs, mainly MMP-2, and MMP-9) are core molecules responsible for the invasiveness of pituitary adenomas. The reason is that these molecules have the ability to directly or indirectly induce cell proliferation, epithelial-to-mesenchymal transition, angiogenesis, degradation, and remodeling of extracellular matrix. HIF-1α induced by hypoxia or apoplexy inside the adenoma might be the initiating factor of invasive transformation, followed with angiogenesis for overexpressed VEGF, EMT for overexpressed PTTG, degradation of ECM for overexpressed MMPs, creating a suitable microenvironment within the tumor. Together, they form a complex interactive network. More investigations are required to further elucidate the mechanisms underlying the invasiveness of pituitary adenomas.

The emerging roles of the polycistronic miR-106b∼25 cluster in cancer - A comprehensive review

MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression at the post-transcriptional level by inhibiting translation and decreasing the stability of the targeted transcripts. Over the last two decades, miRNAs have been recognized as important regulators of cancer cell biology, acting either as oncogenes or tumor suppressors. The polycistronic miR-106b∼25 cluster, located within an intron of MCM7 gene, consists of three highly conserved miRNAs: miR-25, miR-93 and miR-106b. A constantly growing body of evidence indicates that these miRNAs are overexpressed in numerous human malignancies and regulate multiple cellular processes associated with cancer development and progression, including: cell proliferation and survival, invasion, metastasis, angiogenesis and immune evasion. Furthermore, recent studies revealed that miR-106b∼25 cluster miRNAs modulate cancer stem cells characteristics and might promote resistance to anticancer therapies. In light of these novel discoveries, miRNAs belonging to the miR-106b∼25 cluster have emerged as key oncogenic drivers as well as potential biomarkers and plausible therapeutic targets in different tumor types. Herein, we comprehensively review novel findings on the roles of miR-106b∼25 cluster in human cancer, and provide a broad insight into the molecular mechanisms underlying its oncogenic properties.

Recent advances in understanding corticotroph pituitary tumor initiation and progression

Cushing’s disease is the most frequent form of hypercortisolism and is caused by hypophyseal corticotroph adenomas secreting excessive amounts of adrenocorticotropic hormone. Most of the tumors develop sporadically and only a limited number of corticotroph adenomas have been found to be associated with different neuroendocrine syndromes or with familial isolated pituitary adenomas. The pathogenic mechanisms of corticotroph adenomas are largely unknown, but the discovered aberrant chaperoning activity of heat shock protein 90 on the one hand and the presence of ubiquitin-specific protease 8 mutations on the other hand partially explained the causes of their development. Corticotroph tumors arise initially as benign microadenomas but with time form invasively growing aggressive macroadenomas which can switch to corticotroph carcinomas in extremely rare cases. The mechanisms through which corticotroph tumors escape from glucocorticoid negative feedback are still poorly understood, as are the processes that trigger the progression of benign corticotroph adenomas toward aggressive and malignant phenotypes. This review summarizes recent findings regarding initiation and progression of corticotroph pituitary tumors.

Clinically Silent Adrenocorticotropic Hormone-Positive Crooke Cell Adenoma: Case Report and Review of Literature

BACKGROUND

Pituitary adenomas are one of the most common tumors of adulthood; however, subtypes such as Crooke cell adenoma are relatively rare.

CASE DESCRIPTION

We present the case of a 55-year-old woman who presented with new-onset intermittent headache and dizziness. Clinical and laboratory investigations were not suggestive of corticotroph tumor. However, subsequent computed tomography and magnetic resonance imaging scans revealed the presence of a suprasellar pituitary adenoma displacing the optic chiasma superiorly, with hemorrhage and sellar expansion. The lesion was removed by transsphenoidal surgery and the biopsy confirmed the lesion to be a nonfunctioning pituitary macroadenoma. Further investigation revealed that the specimen demonstrated Crooke hyaline changes, with strong immunoreactivity for adrenocorticotropic hormone. However, initial workup and postoperative testing lacked evidence of Cushing disease. There was no sign of recurrence after 1-year follow-up.

CONCLUSIONS

Clinically silent Crooke cell adenomas are rare occurrences, and as such we report this case with investigation of past cases.