Diagnostic Value of Immunostaining for Thyroid Transcription Factor 1 (TTF1) and Paired Box 8 (PAX8) in Distinguishing Pulmonary Metastases of Mesonephric and Mesonephric-like Adenocarcinomas from Primary Lung Adenocarcinomas

BACKGROUND/AIM

Both mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA) express thyroid transcription factor 1 (TTF1). TTF1 is also considered a highly sensitive and specific diagnostic marker for primary lung adenocarcinoma (PLA). However, distinguishing PLA from pulmonary metastatic MA/MLA (PMM) based on the expression of TTF1 alone can be difficult. This study aimed to investigate the expression of TTF1 and paired box 8 (PAX8) and assess their value in distinguishing PMM from PLA.

PATIENTS AND METHODS

We reviewed the electronic medical records and pathology slides of eight PMM cases. We conducted immunostaining for TTF1 and PAX8 in 6, 8, and 21 cases of primary MA/MLA, PMM, and PLA, respectively.

RESULTS

Two patients with stage IB uterine MLA developed lung metastases at 5 and 57 months after hysterectomy. Solitary pulmonary nodules were suspected to be primary lung cancer in two patients. Compared to primary tumors, all matched PMMs exhibited reduced TTF1 immunoreactivity. In contrast, the majority of PLAs showed uniform and intense TTF1 expression. All except one PMM exhibited diffuse and strong PAX8 expression, while only one PLA showed focal and weak PAX8 expression.

CONCLUSION

Immunostaining for TTF1 and PAX8 can help in distinguishing PMM from PLA in the diagnosis of pulmonary lesions detected in patients with a history of MA/MLA.

Non-small cell lung carcinoma with focal coexpression of thyroid transcription factor-1 and Δ Np63/p40: A case report

Most lung carcinomas are subtyped by their morphologies; however, immunohistochemistry is usually performed when it is difficult to determine. The most reliable antibodies for distinguishing lung adenocarcinoma from squamous cell carcinoma are thyroid transcription factor-1 (TTF-1) and p40 (ΔNp63). In general, these markers are mutually exclusive in their expression of lung primary carcinoma; however, a few cases of non-small cell lung carcinoma (NSCLC) with coexpression of both markers have been reported. Examining a tissue microarray of 229 squamous cell carcinomas and 346 adenocarcinomas, we found one case of NSCLC with coexpression of TTF-1 and p40. Herein, we present a 71-year-old man, who had a mass lesion in the left lung apex. A transbronchial lung biopsy was performed, revealing NSCLC. He underwent left upper segmentectomy and lymph node dissection. Macroscopically, the mass showed a white-to-tan solid tumor on the cut surface. Microscopically, the tumor was composed of polygonal tumor cells which had round and vesicular nuclei with prominent nucleoli. They had an abundant amount of cytoplasm, which was slightly eosinophilic or amphophilic. Multinucleated cells with atypical nuclear features were observed to be scattered in some areas. Multifocal necrosis and hemorrhage were also noted. Distinct squamous features and obvious glandular features were absent. Immunohistochemically, the most tumor cells were coexpressed positive for both TTF-1 and p40. In our study, NSCLC with TTF-1 and p40 coexpression is rare; therefore, it is necessary to obtain further data and examine similar cases to establish more precise definitions and clinicopathological features.

Thyroid transcription factor-1 expression in lung neuroendocrine tumours: a gender-related biomarker?

PURPOSE

Thyroid transcription factor-1 (TTF-1) assessed by immunohistochemistry (IHC) is a specific biomarker for lung adenocarcinoma, and is commonly used to confirm the pulmonary origin of neuroendocrine tumours (NET). The majority of the available data suggest that TTF-1 is favourable prognostic biomarker for lung adenocarcinomas, whereas its role is more conflicting for lung NET. The main aim of this multicenter retrospective study was to investigate the potentially relevant associations between TTF-1 biomarker and clinical and pathological features of the study population, as well as determine TTF-1 prognostic effect on the clinical outcome of the patients.

METHODS

A multicentre retrospective study was conducted on 155 surgically-removed lung NET, with available IHC TTF-1 assessment.

RESULTS

Median age was 59.5 years (range 13-86), 97 patients (62.6%) were females, 31 cases (20%) were atypical carcinoids, 4 (2.6%) had TNM stage IV. Mitotic count ≥2 per 10 high-power field was found in 35 (22.6%) subjects, whereas necrosis was detected in 20 patients (12.9%). TTF-1 was positive in 78 cases (50.3%). The median overall survival was 46.9 months (range 0.6-323) and the median progression-free survival was 39.1 months (range 0.6-323). Statistically significant associations were found between (1) TTF-1 positivity and female sex (p = 0.007); and among (2) TTF-1 positivity and the absence of necrosis (p = 0.018).

CONCLUSIONS

This study highlights that TTF-1 positivity differs according to sex in lung NET, with a more common TTF-1 positive staining in female. Moreover, TTF-1 positivity correlated with the absence of necrosis. These data suggest that TTF-1 could potentially represent a gender-related biomarker for lung NET.

Regulatory effect of NK homeobox 1 (NKX2.1) on melanocortin 4 receptor (Mc4r) promoter in Mandarin fish

The melanocortin 4 receptor (MC4R) is a G protein-coupled transporter that mediates the regulation of thyroid hormones and leptin on energy balance and food intake. However, the mechanisms of transcriptional regulation of Mc4r by thyroid hormone and leptin in fish have been rarely reported. The messenger RNA expression of Mc4r gene was significantly higher in brain than those in other tissues of mandarin fish. We analyzed the structure and function of a 2029 bp sequence of Mc4r promoter. Meanwhile, overexpression of NKX2.1 and incubation with leptin significantly increased Mc4r promoter activity, but triiodothyronine showed the opposite effect. In addition, mutations in the NKX2.1 binding site abolished not only the activation of Mc4r promoter activity by leptin but also the inhibitory effect of thyroid hormones on Mc4r promoter activity. In summary, these results suggested that thyroid hormones and leptin might regulate the transcriptional expression of Mc4r through NKX2.1.

Stable iPSC-derived NKX2-1+ lung bud tip progenitor organoids give rise to airway and alveolar cell types

Bud tip progenitors (BTPs) in the developing lung give rise to all epithelial cell types found in the airways and alveoli. This work aimed to develop an iPSC organoid model enriched with NKX2-1+ BTP-like cells. Building on previous studies, we optimized a directed differentiation paradigm to generate spheroids with more robust NKX2-1 expression. Spheroids were expanded into organoids that possessed NKX2-1+/CPM+ BTP-like cells, which increased in number over time. Single cell RNA-sequencing analysis revealed a high degree of transcriptional similarity between induced BTPs (iBTPs) and in vivo BTPs. Using FACS, iBTPs were purified and expanded as induced bud tip progenitor organoids (iBTOs), which maintained an enriched population of bud tip progenitors. When iBTOs were directed to differentiate into airway or alveolar cell types using well-established methods, they gave rise to organoids composed of organized airway or alveolar epithelium, respectively. Collectively, iBTOs are transcriptionally and functionally similar to in vivo BTPs, providing an important model for studying human lung development and differentiation.

Dabrafenib monotherapy for a recurrent BRAFV600E-mutated TTF-1-positive posterior pituitary tumor

Posterior pituitary tumors (PPT) expressing thyroid transcription factor-1 (TTF-1) are extremely rare low-grade neoplasms. The recent discovery of BRAF mutations in these tumors offers a potential alternative treatment using targeted therapies. We present the case of a 57-year-old female with recurrent BRAFV600E-mutated TTF-1-positive PPT treated with a BRAF inhibitor monotherapy (dabrafenib) leading to tumor regression. After 18 months of uninterrupted treatment, ongoing radiological tumor regression was observed and the patient remained asymptomatic without any significant adverse event. BRAF inhibitor is potentially a valuable treatment option for recurrent TTF-1-positive PPT with BRAF mutation.

Transcription start site-level expression of thyroid transcription factor 1 isoforms in lung adenocarcinoma and its clinicopathological significance

There are multiple transcription start sites (TSSs) in agreement with multiple transcript variants encoding different isoforms of NKX2-1/TTF-1 (thyroid transcription factor 1); however, the clinicopathological significance of each transcript isoform of NKX2-1/TTF-1 in lung adenocarcinoma (LAD) is unknown. Herein, TSS-level expression of NKX2-1/TTF-1 isoforms was evaluated in 71 LADs using bioinformatic analysis of cap analysis of gene expression (CAGE)-sequencing data, which provides genome-wide expression levels of the 5'-untranslated regions and the TSSs of different isoforms. Results of CAGE were further validated in 664 LADs using in situ hybridisation. Fourteen of 17 TSSs in NKX2-1/TTF-1 (80% of known TSSs in FANTOM5, an atlas of mammalian promoters) were identified in LADs, including TSSs 1-13 and 15; four isoforms of NKX2-1/TTF-1 transcripts (NKX2-1_001, NKX2-1_002, NKX2-1_004, and NKX2-1_005) were expressed in LADs, although NKX2-1_005 did not contain a homeodomain. Among those, six TSSs regulated NKX2-1_004 and NKX2-1_005, both of which contain exon 1. LADs with low expression of isoforms from TSS region 11 regulating exon 1 were significantly associated with poor prognosis in the CAGE data set. In the validation set, 62 tumours (9.3%) showed no expression of NKX2-1/TTF-1 exon 1; such tumours were significantly associated with older age, EGFR wild-type tumours, and poor prognosis. In contrast, 94 tumours, including 22 of 30 pulmonary invasive mucinous adenocarcinomas (IMAs) exhibited exon 1 expression without immunohistochemical TTF-1 protein expression. Furthermore, IMAs commonly exhibited higher exon 1 expression relative to that of exon 4/5, which contained a homeodomain in comparison with EGFR-mutated LADs. These transcriptome and clinicopathological results reveal that LAD use at least 80% of NKX2-1 TSSs and expression of the NKX2-1/TTF-1 transcript isoform without exon 1 (NKX2-1_004 and NKX2-1_005) defines a distinct subset of LAD characterised by aggressive behaviour in elder patients. Moreover, usage of alternative TSSs regions regulating NKX2-1_005 may occur in subsets of LADs.

A Positive Feedback Loop Between DICER1 and Differentiation Transcription Factors Is Important for Thyroid Tumorigenesis

Background: DICER1 plays a central role in microRNA biogenesis and functions as a tumor suppressor in thyroid cancer, which is the most frequent endocrine malignancy with a rapidly increasing incidence. Thyroid cancer progression is associated with loss of cell differentiation and reduced expression of thyroid differentiation genes and response to thyrotropin (TSH). Here we investigated whether a molecular link exists between DICER1 and thyroid differentiation pathways. Methods: We used bioinformatic tools to search for transcription factor binding sites in the DICER1 promoter. DICER1, NKX2-1, PAX8, and CREB expression levels were evaluated by gene and protein expression in vitro and by interrogation of The Cancer Genome Atlas (TCGA) thyroid cancer data. Transcription factor binding and activity were assayed by chromatin immunoprecipitation, band-shift analysis, and promoter-reporter gene activity. Gene-silencing and overexpression approaches were used to elucidate the functional link between DICER1 and differentiation. Results: We identified binding sites for NKX2-1 and CREB within the DICER1 promoter and found that both transcription factors are functional in thyroid cells. TSH induced DICER1 expression in differentiated thyroid cells, at least in part, through the cAMP/PKA/CREB pathway. TCGA analysis revealed a significant positive correlation between CREB and DICER1 expression in human thyroid tumors. NKX2-1 overexpression increased DICER1 promoter activity and expression in vitro, and this was significantly greater in the presence of CREB and/or PAX8. Gain- and loss-of-function assays revealed that DICER1 regulates NKX2-1 expression in thyroid tumor cells and vice versa, thus establishing a positive feedback loop between both proteins. We also found a positive correlation between NKX2-1 and DICER1 expression in human thyroid tumors. DICER1 silencing decreased PAX8 expression and, importantly, the expression and activity of the sodium iodide symporter, which is essential for the diagnostic and therapeutic use of radioiodine in thyroid cancer. Conclusions: The differentiation transcription factors NKX2.1, PAX8, and CREB act in a positive feedback loop with DICER1. As the expression of these transcription factors is markedly diminished in thyroid cancer, our findings suggest that DICER1 downregulation in this cancer is mediated, at least partly, through impairment of its transcription.

An NKX2-1/ERK/WNT feedback loop modulates gastric identity and response to targeted therapy in lung adenocarcinoma

Cancer cells undergo lineage switching during natural progression and in response to therapy. NKX2-1 loss in human and murine lung adenocarcinoma leads to invasive mucinous adenocarcinoma (IMA), a lung cancer subtype that exhibits gastric differentiation and harbors a distinct spectrum of driver oncogenes. In murine BRAFV600E-driven lung adenocarcinoma, NKX2-1 is required for early tumorigenesis, but dispensable for established tumor growth. NKX2-1-deficient, BRAFV600E-driven tumors resemble human IMA and exhibit a distinct response to BRAF/MEK inhibitors. Whereas BRAF/MEK inhibitors drive NKX2-1-positive tumor cells into quiescence, NKX2-1-negative cells fail to exit the cell cycle after the same therapy. BRAF/MEK inhibitors induce cell identity switching in NKX2-1-negative lung tumors within the gastric lineage, which is driven in part by WNT signaling and FoxA1/2. These data elucidate a complex, reciprocal relationship between lineage specifiers and oncogenic signaling pathways in the regulation of lung adenocarcinoma identity that is likely to impact lineage-specific therapeutic strategies.

Novel insights into di‑(2‑ethylhexyl)phthalate activation: Implications for the hypothalamus‑pituitary‑thyroid axis

Di (2‑ethylhexyl) phthalate (DEHP), an environmental pollutant, is widely used as a plasticizer and causes serious pollution in the ecological environment. As previously reported, exposure to DEHP may cause thyroid dysfunction of the hypothalamic‑pituitary‑thyroid (HPT) axis. However, the underlying role of DEHP remains to be elucidated. The present study performed intragastrical administration of DEHP (150, 300 and 600 mg/kg) once a day for 90 consecutive days. DEHP‑stimulated oxidative stress increased the thyroid follicular cavity diameter and caused thyrocyte oedema. Furthermore, DEHP exposure altered mRNA and protein levels. Thus, DEHP may perturb TH homeostasis by affecting biosynthesis, biotransformation, bio‑transportation, receptor levels and metabolism through disruption of the HPT axis and activation of the thyroid‑stimulating hormone (TSH)/TSH receptor signaling pathway. These results identified the formerly unappreciated endocrine‑disrupting activities of phthalates and the molecular mechanisms of DEHP‑induced thyrotoxicity.

TTF-1 and c-MYC-defined Phenotypes of Large Cell Neuroendocrine Carcinoma and Delta-like Protein 3 Expression for Treatment Selection

The standard treatment regimen has not yet been established for advanced pulmonary large cell neuroendocrine carcinoma (LCNEC) because of its rarity. LCNEC can be subdivided into 2 mutually exclusive molecular subgroups: STK11/KEAP1 and TP53 mutated with high neuroendocrine expression and transcriptional profile of ASCL1high/DLL3high/NOTCHlow (non-small cell lung carcinoma, NSCLC-like) or RB1 and TP53 mutated with reduced neuroendocrine markers and transcriptional pattern of ASCL1low/DLL3low/NOTCHhigh (small cell lung cancer, SCLC-like). Model-based clustering shows that SCLC has subdivided into 2 major proteomic subsets defined by either TTF-1high/c-MYClow or TTF-1low/c-MYChigh, which may correspond to 2 mutually exclusive molecular subgroups: NSCLC-like or SCLC-like, respectively. We herein investigated whether TTF-1 and c-MYC could be applied to LCNEC to identify distinct subsets immunohistochemically and assessed DLL3 expression in these subsets. The protein expression profile may be useful to select patients for potential efficacy of targeted therapies including aurora kinase inhibitors for MYC alterations or anti-DLL3 antibody-drug conjugates. TTF-1 and c-MYC expression was mutually exclusive in 25 of 27 (93%) cases; TTF-1+/c-MYC- in 10, TTF-1-/c-MYC+ in 15, and TTF-1+/c-MYC+ in 2. DLL3 expression was seen in 15 of 27 cases (56%). All 12 TTF-1+ LCNEC cases were positive for DLL3. Three of 15 (20%) TTF-1-/c-MYC+ cases showed DLL3 positivity. LCNEC could be separated into 2 subsets proteomically defined by TTF-1 and c-MYC expression, which may be suitable to guide treatment selection including aurora kinase inhibitors for c-MYC+ cases. TTF-1 positivity can serve as a surrogate marker for DLL3, but caution is necessary as 20% of TTF-1- cases showed DLL3 positivity.

Downregulation of TTF1 in the rat hypothalamic ARC or AVPV nucleus inhibits Kiss1 and GnRH expression, leading to puberty delay

BACKGROUND

TTF1 is a transcription factor that is expressed in the hypothalamus after birth and plays crucial roles in pubertal development. TTF1 may regulate the expression of the Kiss1 gene, which may drive puberty onset in the hypothalamic arcuate (ARC) and anterior ventral paraventricular (AVPV) nuclei.

METHODS

A dual-luciferase reporter assay was used to detect binding between TTF1 and the Kiss1 gene promoter. To investigate the effects of TTF1, we modified TTF1 expression in cell lines and in the ARC or AVPV nucleus of 21-day-old female rats via lentivirus infection. TTF1 and other puberty onset-related genes were detected by qRT-PCR and western blot analyses.

RESULTS

The in vitro data indicated that TTF1 knockdown (KD) significantly reduced Kiss1 and GnRH expression. Overexpression (OE) of TTF1 promoted Kiss1 expression. In vivo, the expression of Kiss1 and GnRH decreased significantly in the rats with hypothalamic ARC- or AVPV-specific TTF1 KD. The TTF1-KD rats showed vaginal opening delay. H&E staining revealed that the corpus luteum was obviously reduced at the early puberty and adult stages in the rats with ARC- or AVPV-specific TTF1 KD.

CONCLUSION

TTF1 bound to the promoter of the Kiss1 gene and enhanced its expression. For 21-day-old female rats, decreased TTF1 in the hypothalamic ARC or AVPV nucleus resulted in delayed vaginal opening and ovarian abnormalities. These observations suggested that TTF1 regulates puberty onset by promoting the expression of Kiss1 and plays an important role in gonad development.

Unraveling the Complex Interplay Between Transcription Factors and Signaling Molecules in Thyroid Differentiation and Function, From Embryos to Adults

Thyroid differentiation of progenitor cells occurs during embryonic development and in the adult thyroid gland, and the molecular bases of these complex and finely regulated processes are becoming ever more clear. In this Review, we describe the most recent advances in the study of transcription factors, signaling molecules and regulatory pathways controlling thyroid differentiation and development in the mammalian embryo. We also discuss the maintenance of the adult differentiated phenotype to ensure the biosynthesis of thyroid hormones. We will focus on endoderm-derived thyroid epithelial cells, which are responsible for the formation of the thyroid follicle, the functional unit of the thyroid gland. The use of animal models and pluripotent stem cells has greatly aided in providing clues to the complicated puzzle of thyroid development and function in adults. The so-called thyroid transcription factors - Nkx2-1, Foxe1, Pax8 and Hhex - were the first pieces of the puzzle identified in mice. Other transcription factors, either acting upstream of or directly with the thyroid transcription factors, were subsequently identified to, almost, complete the puzzle. Among them, the transcription factors Glis3, Sox9 and the cofactor of the Hippo pathway Taz, have emerged as important players in thyroid differentiation and development. The involvement of signaling molecules increases the complexity of the puzzle. In this context, the importance of Bmps, Fgfs and Shh signaling at the onset of development, and of TSH, IGF1 and TGFβ both at the end of terminal differentiation in embryos and in the adult thyroid, are well recognized. All of these aspects are covered herein. Thus, readers will be able to visualize the puzzle of thyroid differentiation with most - if not all - of the pieces in place.

The cellular and molecular landscape of hypothalamic patterning and differentiation from embryonic to late postnatal development

The hypothalamus is a central regulator of many innate behaviors essential for survival, but the molecular mechanisms controlling hypothalamic patterning and cell fate specification are poorly understood. To identify genes that control hypothalamic development, we have used single-cell RNA sequencing (scRNA-Seq) to profile mouse hypothalamic gene expression across 12 developmental time points between embryonic day 10 and postnatal day 45. This identified genes that delineated clear developmental trajectories for all major hypothalamic cell types, and readily distinguished major regional subdivisions of the developing hypothalamus. By using our developmental dataset, we were able to rapidly annotate previously unidentified clusters from existing scRNA-Seq datasets collected during development and to identify the developmental origins of major neuronal populations of the ventromedial hypothalamus. We further show that our approach can rapidly and comprehensively characterize mutants that have altered hypothalamic patterning, identifying Nkx2.1 as a negative regulator of prethalamic identity. These data serve as a resource for further studies of hypothalamic development, physiology, and dysfunction.

Bidirectional Wnt signaling between endoderm and mesoderm confers tracheal identity in mouse and human cells

The periodic cartilage and smooth muscle structures in mammalian trachea are derived from tracheal mesoderm, and tracheal malformations result in serious respiratory defects in neonates. Here we show that canonical Wnt signaling in mesoderm is critical to confer trachea mesenchymal identity in human and mouse. At the initiation of tracheal development, endoderm begins to express Nkx2.1, and then mesoderm expresses the Tbx4 gene. Loss of β-catenin in fetal mouse mesoderm causes loss of Tbx4+ tracheal mesoderm and tracheal cartilage agenesis. The mesenchymal Tbx4 expression relies on endodermal Wnt activation and Wnt ligand secretion but is independent of known Nkx2.1-mediated respiratory development, suggesting that bidirectional Wnt signaling between endoderm and mesoderm promotes trachea development. Activating Wnt, Bmp signaling in mouse embryonic stem cell (ESC)-derived lateral plate mesoderm (LPM) generates tracheal mesoderm containing chondrocytes and smooth muscle cells. For human ESC-derived LPM, SHH activation is required along with WNT to generate proper tracheal mesoderm. Together, these findings may contribute to developing applications for human tracheal tissue repair.

Delineating the early transcriptional specification of the mammalian trachea and esophagus

The genome-scale transcriptional programs that specify the mammalian trachea and esophagus are unknown. Though NKX2-1 and SOX2 are hypothesized to be co-repressive master regulators of tracheoesophageal fates, this is untested at a whole transcriptomic scale and their downstream networks remain unidentified. By combining single-cell RNA-sequencing with bulk RNA-sequencing of Nkx2-1 mutants and NKX2-1 ChIP-sequencing in mouse embryos, we delineate the NKX2-1 transcriptional program in tracheoesophageal specification, and discover that the majority of the tracheal and esophageal transcriptome is NKX2-1 independent. To decouple the NKX2-1 transcriptional program from regulation by SOX2, we interrogate the expression of newly-identified tracheal and esophageal markers in Sox2/Nkx2-1 compound mutants. Finally, we discover that NKX2-1 binds directly to Shh and Wnt7b and regulates their expression to control mesenchymal specification to cartilage and smooth muscle, coupling epithelial identity with mesenchymal specification. These findings create a new framework for understanding early tracheoesophageal fate specification at the genome-wide level.

Mechanisms of larynx and vocal fold development and pathogenesis

The larynx and vocal folds sit at the crossroad between digestive and respiratory tracts and fulfill multiple functions related to breathing, protection and phonation. They develop at the head and trunk interface through a sequence of morphogenetic events that require precise temporo-spatial coordination. We are beginning to understand some of the molecular and cellular mechanisms that underlie critical processes such as specification of the laryngeal field, epithelial lamina formation and recanalization as well as the development and differentiation of mesenchymal cell populations. Nevertheless, many gaps remain in our knowledge, the filling of which is essential for understanding congenital laryngeal disorders and the evaluation and treatment approaches in human patients. This review highlights recent advances in our understanding of the laryngeal embryogenesis. Proposed genes and signaling pathways that are critical for the laryngeal development have a potential to be harnessed in the field of regenerative medicine.

Development of an In Vitro Human Thyroid Microtissue Model for Chemical Screening

Thyroid hormones (TH) are essential for regulating a number of diverse physiological processes required for normal growth, development, and metabolism. The US EPA Endocrine Disruptor Screening Program (EDSP) has identified several molecular thyroid targets relevant to hormone synthesis dynamics that have been adapted to high-throughput screening (HTS) assays to rapidly evaluate the ToxCast/Tox21 chemical inventories for potential thyroid disrupting chemicals (TDCs). The uncertainty surrounding the specificity of active chemicals identified in these screens and the relevance to phenotypic effects on in vivo human TH synthesis are notable data gaps for hazard identification of TDCs. The objective of this study was to develop a medium-throughput organotypic screening assay comprised of reconstructed human thyroid microtissues to quantitatively evaluate the disruptive effects of chemicals on TH production and secretion. Primary human thyroid cells procured from qualified euthyroid donors were analyzed for retention of NK2 homeobox 1 (NKX2-1), Keratin 7 (KRT7), and Thyroglobulin (TG) protein expression by high-content image analysis to verify enrichment of follicular epithelial cells. A direct comparison of 2-dimensional (2D) and 3-dimensional (3D) 96-well culture formats was employed to characterize the morphology, differential gene expression, TG production, and TH synthesis over the course of 20 days. The results indicate that modeling human thyroid cells in the 3D format was sufficient to restore TH synthesis not observed in the 2D culture format. Inhibition of TH synthesis in an optimized 3D culture format was demonstrated with reference chemicals for key molecular targets within the thyroid gland. Implementation of the assay may prove useful for interpreting phenotypic effects of candidate TDCs identified by HTS efforts currently underway in the EDSP.

The in vivo genetic program of murine primordial lung epithelial progenitors

Multipotent Nkx2-1-positive lung epithelial primordial progenitors of the foregut endoderm are thought to be the developmental precursors to all adult lung epithelial lineages. However, little is known about the global transcriptomic programs or gene networks that regulate these gateway progenitors in vivo. Here we use bulk RNA-sequencing to describe the unique genetic program of in vivo murine lung primordial progenitors and computationally identify signaling pathways, such as Wnt and Tgf-β superfamily pathways, that are involved in their cell-fate determination from pre-specified embryonic foregut. We integrate this information in computational models to generate in vitro engineered lung primordial progenitors from mouse pluripotent stem cells, improving the fidelity of the resulting cells through unbiased, easy-to-interpret similarity scores and modulation of cell culture conditions, including substratum elastic modulus and extracellular matrix composition. The methodology proposed here can have wide applicability to the in vitro derivation of bona fide tissue progenitors of all germ layers.

Npas1+-Nkx2.1+ Neurons Are an Integral Part of the Cortico-pallido-cortical Loop

Within the basal ganglia circuit, the external globus pallidus (GPe) is critically involved in motor control. Aside from Foxp2+ neurons and ChAT+ neurons that have been established as unique neuron types, there is little consensus on the classification of GPe neurons. Properties of the remaining neuron types are poorly defined. In this study, we leverage new mouse lines, viral tools, and molecular markers to better define GPe neuron subtypes. We found that Sox6 represents a novel, defining marker for GPe neuron subtypes. Lhx6+ neurons that lack the expression of Sox6 were devoid of both parvalbumin and Npas1. This result confirms previous assertions of the existence of a unique Lhx6+ population. Neurons that arise from the Dbx1+ lineage were similarly abundant in the GPe and displayed a heterogeneous makeup. Importantly, tracing experiments revealed that Npas1+-Nkx2.1+ neurons represent the principal noncholinergic, cortically-projecting neurons. In other words, they form the pallido-cortical arm of the cortico-pallido-cortical loop. Our data further show that pyramidal-tract neurons in the cortex collateralized within the GPe, forming a closed-loop system between the two brain structures. Overall, our findings reconcile some of the discrepancies that arose from differences in techniques or the reliance on preexisting tools. Although spatial distribution and electrophysiological properties of GPe neurons reaffirm the diversification of GPe subtypes, statistical analyses strongly support the notion that these neuron subtypes can be categorized under the two principal neuron classes: PV+ neurons and Npas1+ neurons.SIGNIFICANCE STATEMENT The poor understanding of the neuronal composition in the external globus pallidus (GPe) undermines our ability to interrogate its precise behavioral and disease involvements. In this study, 12 different genetic crosses were used, hundreds of neurons were electrophysiologically characterized, and >100,000 neurons were histologically- and/or anatomically-profiled. Our current study further establishes the segregation of GPe neuron classes and illustrates the complexity of GPe neurons in adult mice. Our results support the idea that Npas1+-Nkx2.1+ neurons are a distinct GPe neuron subclass. By providing a detailed analysis of the organization of the cortico-pallidal-cortical projection, our findings establish the cellular and circuit substrates that can be important for motor function and dysfunction.

Increased Anaplastic Lymphoma Kinase Activity Induces a Poorly Differentiated Thyroid Carcinoma in Mice

Background: Radioiodine refractory dedifferentiated thyroid cancer is a major clinical challenge. Anaplastic lymphoma kinase (ALK) mutations with increased ALK activity, especially fusion genes, have been suggested to promote thyroid carcinogenesis, leading to development of poorly differentiated thyroid carcinoma (PDTC) and anaplastic thyroid carcinoma. To determine the oncogenic potential of increased ALK activity in thyroid carcinogenesis in vivo, we studied mice with thyrocyte-specific expression of a constitutively active ALK mutant. Methods: Mice carrying a Cre-activated allele of a constitutively active ALK mutant (F1174L) were crossed with mice expressing tamoxifen-inducible Cre recombinase (CreER^T2) under the control of the thyroglobulin (Tg) gene promoter to achieve thyrocyte-specific expression of the ALK mutant (ALK^F1174L mice). Survival, thyroid hormone serum concentration, and tumor development were recorded. Thyroids and lungs were studied histologically. To maintain euthyroidism despite dedifferentiation of the thyroid, a cohort was substituted with levothyroxine (LT4) through drinking water. Results: ALK^F1174L mice developed massively enlarged thyroids, which showed an early loss of normal follicular architecture 12 weeks after tamoxifen injection. A significant decrease in Tg and Nkx-2.1 expression as well as impaired thyroid hormone synthesis confirmed dedifferentiation. Histologically, the mice developed a carcinoma resembling human PDTC with a predominantly trabecular/solid growth pattern and an increased mitotic rate. The tumors showed extrathyroidal extension into the surrounding strap muscles and developed lung metastases. Median survival of ALK^F1174L mice was significantly reduced to five months after tamoxifen injection. Reduced Tg expression and loss of follicular structure led to hypothyroidism with elevated thyrotropin (TSH). To test whether TSH stimulation played a role in thyroid carcinogenesis, we kept ALK^F1174L mice euthyroid by LT4 substitution. These mice developed PDTC with identical histological features compared with hypothyroid mice, demonstrating that PDTC development was due to increased ALK activity and not dependent on TSH stimulation. Conclusion: Expression of a constitutively activated ALK mutant in thyroids of mice leads to development of metastasizing thyroid cancer resembling human PDTC. These results demonstrate in vivo that increased ALK activity is a driver mechanism in thyroid carcinogenesis.

Functions of stem cells of thyroid glands in health and disease

Thyroid gland has been implicated in the regulation of many functions using endocrine, paracrine and autocrine signals. Functional thyroid follicular cells derived from stem cells attracted a great interest from researchers as a strategy for thyroid's regenerative therapy. Thyroid has a very low rate of turnover; however, studies showed that the regenerative ability is enhanced following diseases or thyroidectomy, which promotes the role of stem cell. The objective of this review is to summarize the morphological characterization and the expression of stem cell genes/markers in the thyroid. Also, to highlight the mechanisms of tumor formation in thyroid via its stem cells. The most important thyroid stem cell's markers are: stem cell antigen 1 (SCA-1), octamer-binding transcription 4 (OCT-4), p63, CD34+ CD45-, paired box gene 8 (PAX-8), thyroid transcription factor 1 (TTF-1), thyroid transcription factor 2 (TTF-2), hematopoietically expressed homeobox protein HHEX, the transcription factor GATA-4, hepatocyte nuclear factor 4-α (HNF-4-α) and homeobox transcription factor Nanog (hNanog). This review highlights the functional characterization describing the mechanisms of stem cell's differentiation into functional thyroid follicle and proposing mechanisms involving in cancer formation through one of these cell types: fetal cell, thyroblasts, prothyrocytes, certain genetic mutation in the mature thyroid cells or presence of a special type of cells (cancer stem cell) which are responsible for different types of cancer formation. Understanding the mechanisms of thyroid's stem cell in cancer formation and the expression of the biomarkers in normal and abnormal thyroid status are promising physiological tools in promoting thyroid regeneration and in provision management for thyroid cancer.

MOLECULAR-BIOLOGICAL THYROID PROFILE DURING AUTOIMMUNE DISEASE - HASHIMOTO AND RIEDEL'S THYROIDITIS

Investigated 62 sample of thyroid gland obtained after surgical intervention, including: HT (n=27), RT (n=9), Graves' disease (n=17) and papillary thyroid carcinoma (n = 10). The slides were studied using classical histological and immunohistochemical methods: H&E, TTF1, TSH, S100-protein, CD56 and p63. Dispite of the histological and immunohistochemical heterogeneity of Thyroiditis HT and RT, the progressive involution of the glandular tissue with the replacement by the sever fibrosis, in some cases by the scar tissue is observed as damage sign. In Hashimoto thyroiditis, the foci of follicular epithelium dysplasia were determined, with p63 positive and CD56 negative reactions. Graves' disease is characterized by high TSH expression as well as lymphoproliferation with the formation of large fused nodules with germinative centers. With Riedel's thyroiditis, there is a moderate expression of TTF-1 in the stroma and capillary endotheliocytes, as well as diffuse-focal moderate expression of S100 protein in cells of neuroectodermal population. The reaction to malignant transformation markers - CD56 and p63 - in the tissue of Thyroid gland with Thyroiditis, Riedel was definitely negative.

Neuroendocrine Liver Metastasis-a Specific Set of Markers to Detect Primary Tumor Sites

The diagnosis of neuroendocrine neoplasia (NEN) is often made at an advanced stage of disease, including hepatic metastasis. At this point, the primary may still be unknown and sometimes cannot even be detected by functional imaging, especially in very small tumors of the pancreas (pan) and small intestinal (si) entities. The site of the primary may be based on biopsy specimens of the liver applying a specific set of markers. Specimens of liver metastases from 87 patients with NENs were studied. In retrospect, 50 patients had si and 37 pan NENs. Tissue samples were evaluated by immunohistochemistry. The markers applied were insulin gene enhancer protein Islet-1 (ISL-1), homeobox protein CDX-2 (CDX2), thyroid transcription factor 1 (TTF-1), and serotonin. Positive stains for CDX2 were documented in 43 (86%) and for serotonin in 45 (90%) of 50 siNENs. Three panNENs were positive for CDX2 and one for serotonin, respectively. ISL-1 was negative throughout in siNENs and also negative in 8 of 50 panNENs (21.6%). TTF-1 was negative in more than 90% of the specimens of either entity. Immunohistochemical markers in liver metastasis can lead the way to the site of the primary NEN. They should always be used in combined clusters.

The Epigenetic Factor CBP Is Required for the Differentiation and Function of Medial Ganglionic Eminence-Derived Interneurons

The development of inhibitory circuits depends on the action of a network of transcription factors and epigenetic regulators that are critical for interneuron specification and differentiation. Although the identity of many of these transcription factors is well established, much less is known about the specific contribution of the chromatin-modifying enzymes that sculpt the interneuron epigenome. Here, we generated a mouse model in which the lysine acetyltransferase CBP is specifically removed from neural progenitors at the median ganglionic eminence (MGE), the structure where the most abundant types of cortical interneurons are born. Ablation of CBP interfered with the development of MGE-derived interneurons in both sexes, causing a reduction in the number of functionally mature interneurons in the adult forebrain. Genetic fate mapping experiments not only demonstrated that CBP ablation impacts on different interneuron classes, but also unveiled a compensatory increment of interneurons that escaped recombination and cushion the excitatory-inhibitory imbalance. Consistent with having a reduced number of interneurons, CBP-deficient mice exhibited a high incidence of spontaneous epileptic seizures, and alterations in brain rhythms and enhanced low gamma activity during status epilepticus. These perturbations led to abnormal behavior including hyperlocomotion, increased anxiety and cognitive impairments. Overall, our study demonstrates that CBP is essential for interneuron development and the proper functioning of inhibitory circuitry in vivo.

NKX2-1-AS1 negatively regulates CD274/PD-L1, cell-cell interaction genes, and limits human lung carcinoma cell migration

The function of most long noncoding RNAs (lncRNAs) is unknown. However, recent studies reveal important roles of lncRNAs in regulating cancer-related pathways. Human antisense lncRNA-NKX2-1-AS1 partially overlaps the NKX2-1/TTF1 gene within chromosomal region 14q13.3. Amplification of this region and/or differential expression of genes therein are associated with cancer progression. Herein we show higher levels of NKX2-AS1 and NKX2-1 in lung adenocarcinomas relative to non-tumor controls but no correlation between NKX2-1-AS1 and NKX2-1 levels across specimens, or with amplification of the 14q13.3 region, suggesting that NKX2-1-AS1 and NKX2-1 are independently regulated. Loss-and-gain of function experiments showed that NKX2-1-AS1 does not regulate NKX2-1 expression, or nearby genes, but controls genes in trans. Genes up-regulated by NKX2-1-AS1-knockdown belong to cell adhesion and PD-L1/PD-1 checkpoint pathways. NKX2-1-AS1 negatively regulates endogenous CD274/PD-L1, a known target of NKX2-1, and the transcriptional activity of -1kb-CD274 promoter-reporter construct. Furthermore, NKX2-1-AS1 interferes with NKX2-1 protein binding to the CD274-promoter, likely by NKX2-1 protein-NKX2-1-AS1 interactions. Finally, NKX2-1-AS1 negatively regulates cell migration and wound healing, but not proliferation or apoptosis. These findings support potential roles of NKX2-1-AS1 in limiting motility and immune system evasion of lung carcinoma cells, highlighting a novel mechanism that may influence tumorigenic capabilities of lung epithelial cells.

Differential expression of neuroendocrine markers, TTF-1, p53, and Ki-67 in cervical and pulmonary small cell carcinoma

Small cell carcinoma (SCC) is a highly malignant neuroendocrine tumor that may occur in many anatomic sites of the body.In this study, we compared the different expression of neuroendocrine markers, thyroid transcription factor 1 (TTF-1), p53, and Ki-67 in 23 cases of cervical SCC and 56 cases of pulmonary SCC using immunohistochemistry.Our study showed that cervical SCC had a younger onset age than pulmonary counterpart. Although both had the similar morphological features, different immunohistochemical expression panel was observed in this study. As neuroendocrine tumors, SCC of cervix and lung had similar immunoreactive staining for CD56 and chromogranin A, but the expression of the synaptophysin in cervical SCC was significantly higher than that in pulmonary SCC (P = .007). The TTF-1 expression of pulmonary SCC illustrating diffuse and strong positivity in tumor cell nuclei was significantly higher than that of the cervical SCC (P = .003). There was only 1 case showing p53 protein over-expression in the 23 cases of cervical SCC, and p53 over-expression was observed in 42.9% of pulmonary SCC (P = .001). Only 9 cases of cervical SCC showed ≥80% of the Ki-67 proliferation index, while it was found in 94.6% of pulmonary SCC (P < .001).The different immunohistochemical expressions of these 2 kinds of SCCs may be related with their pathogenetic mechanism, and these differences may be helpful in the identification of the origins of the metastatic SCC with unknown primary site.

Absence of thyroid transcription factor-1 expression is associated with poor survival in patients with advanced pulmonary adenocarcinoma treated with pemetrexed-based chemotherapy

INTRODUCTION

Adenocarcinoma is the commonest histologic subtype of lung cancer and is often identified by immunohistochemical staining for thyroid transcription factor-1 (TTF-1). However, up to 20% of lung adenocarcinomas do not express TTF-1, and there is uncertainty regarding the significance of this. We aimed to evaluate the prognostic effect of TTF-1 expression status on survival in patients treated with pemetrexed-based chemotherapy for advanced adenocarcinoma of the lung.

METHODS

This retrospective study included patients treated with pemetrexed-based chemotherapy for stage IIIB/IV lung adenocarcinoma, who had known TTF-1 expression status. Clinical and demographic data were obtained from medical records. Overall survival (OS) was estimated using the Kaplan-Meier method, and differences in survival between groups assessed using the Cox proportional hazards model.

RESULTS

Forty-four patients were identified with documented TTF-1 expression: 35 with TTF-1-positive and 9 with TTF-1-negative disease. Patients in the TTF-1-negative group had poorer performance scores than those in the TTF-1-positive group (ECOG 2: 67 vs 20%, p = 0.008), and received less chemotherapy (median cycles 2 vs 4, p = 0.009), and were fewer in treatment with doublet regimens (22 vs 69%, p = 0.013). OS was significantly shorter in the TTF-1-negative group than in the TTF-1-positive group (2.4 vs 11.5 months, HR 8.38, p < 0.0001).

CONCLUSIONS

In this group of patients treated with pemetrexed-based chemotherapy for advanced pulmonary adenocarcinoma, absence of TTF-1 expression was associated with an aggressive tumor phenotype, poorer performance status, and poor survival. This subgroup of patients should be recognized as having a distinct clinical course, with limited benefit from standard chemotherapy.

Thyroid transcription factor 1 enhances cellular statin sensitivity via perturbing cholesterol metabolism

We have discovered an unexpected connection between a critical lung development and cancer gene termed thyroid transcription factor 1 (TTF-1 also known as NKX2-1) and cholesterol metabolism. Our published work implicates that TTF-1 positively regulates miR-33a which is known to repress ATP-binding cassette transporter 1 (ABCA1) and thus its cholesterol efflux activity. We set out to demonstrate that a higher TTF-1 expression would presumably inhibit cholesterol efflux and consequently raise intracellular cholesterol level. Surprisingly, raising TTF-1 expression actually lowers intracellular cholesterol level, which, we believe, is attributed to a direct transactivation of ABCA1 by TTF-1. Subsequently, we show that lung cancer cells primed with a TTF-1-driven decrease of cholesterol were more vulnerable to simvastatin, a frequently prescribed cholesterol biosynthesis inhibitor. In view of the fact that pathologists routinely interrogate human lung cancers for TTF-1 immunopositivity to guide diagnosis and the prevalent use of statins, TTF-1 should be further investigated as a putative biomarker of lung cancer vulnerability to statins.

Thyroid follicular carcinoma-like renal tumor: A case report and literature review

RATIONALE

Thyroid follicular carcinoma-like renal tumor (TFCLRT) is a rare primary renal epithelial tumor that was first reported in 2006. We report a case diagnosed of TFCLRT by us to observe the pathological feature and analyze comparatively the clinical and pathologic characteristics with all cases of reviewed literatures.

PATIENT CONCERNS

A 54-year-old female patient had the urinary frequency with the symptom of right flank pain with a history of more than half a year of hypertension and received uterine fibroid resection 12 years ago. B-mode ultrasound examination and renal magnetic resonance showed a right renal sinus nodule.

DIAGNOSES

Histopathology revealed thyroid follicle-like structures of different sizes, containing a colloid-like substance, while the periodic acid-Schiff (PAS) and diastase-resistant PAS staining confirmed that it was mucus protein. Immunohistochemical staining showed that it expresses the transcription factor PAX-8 but does not express the thyroid-specific antibodies TG and TTF-1.

INTERVENTIONS

The patient underwent a tumor enucleation of right kidney. No other treatment was conducted after surgery.

OUTCOMES

No metastases to lymph nodes and other organs were found, and 9-months of follow-up did not reveal any tumor progression.

LESSONS

We should differentially diagnose the renal metastasis of thyroid follicular carcinoma or papillary carcinoma. Some related literatures reported that the tumour cells had significant heteromorphism, several of which metastasized to lymph nodes or distal organs. Its biological behavior need to be studied intensively by further expanding the number of cases.

Developmental History Provides a Roadmap for the Emergence of Tumor Plasticity

We show that the loss or gain of transcription factor programs that govern embryonic cell-fate specification is associated with a form of tumor plasticity characterized by the acquisition of alternative cell fates normally characteristic of adjacent organs. In human non-small cell lung cancers, downregulation of the lung lineage-specifying TF NKX2-1 is associated with tumors bearing features of various gut tissues. Loss of Nkx2-1 from murine alveolar, but not airway, epithelium results in conversion of lung cells to gastric-like cells. Superimposing oncogenic Kras activation enables further plasticity in both alveolar and airway epithelium, producing tumors that adopt midgut and hindgut fates. Conversely, coupling Nkx2-1 loss with foregut lineage-specifying SOX2 overexpression drives the formation of squamous cancers with features of esophageal differentiation. These findings demonstrate that elements of pathologic tumor plasticity mirror the normal developmental history of organs in that cancer cells acquire cell fates associated with developmentally related neighboring organs.

Establishment of patient-derived tumor spheroids for non-small cell lung cancer

The prognosis of advanced non-small cell lung cancer (NSCLC) patients is poor. One of the reasons for this hampered progress has been a lack of in vitro models that would faithfully recapitulate the heterogeneity of tumors and response to treatment. In this study, surgically resected tumors were obtained from patients with stage I/II NSCLC during curative-intent surgery. Using a 3D patient-derived tumor spheroids culture system, our results demonstrate successful long-term expansion of primary NSCLC cells in vitro (> 120 days). Patient-derived tumor spheroid (PDS) cultures could be established with a success rate of 100% (3 out of 3 samples). Consistent with their growth in culture and their cancer type, many cells within the tumor spheroids were stained positive for Ki67 and thyroid transcription factor-1. The result of this study supports the establishment of an expandable 3D in vitro NSCLC model for drug screening, and enables the potential long term studies such as the establishment of drug resistant models.

Evaluation of hypothalamus-pituitary-thyroid axis function by chronic perchlorate exposure in male rats

Perchlorate is a widespread endocrine disruptor that was previously correlated with increased serum TSH levels and decreased thyroid hormones production both in animals and humans. Even so, the regulation of gene/protein expression in the hypothalamus, pituitary and thyroid by chronic perchlorate exposure was not completely elucidated. Therefore, this study aimed to investigate the underlying mechanisms involved in the disruption of hypothalamus-pituitary-thyroid axis by chronic perchlorate exposure. Male Wistar rats were treated or not with NaClO₄ in the drinking water (35 mg/Kg/day) for 60 days. Thereafter, hormone/cytokines serum levels were measured through multiplex assays; genes/proteins expression were investigated by qPCR/Western Blotting and thyroid morphology was evaluated through histological analysis. Serum TSH levels were increased and serum T₄ /T₃ levels were decreased in perchlorate-treated animals. This treatment also altered the thyrotropin-releasing hormone mRNA/protein content in the hypothalamus. Additionally, the expression of both subunits of TSH were increased in the pituitary of perchlorate-treated rats, which also presented significant alterations in the thyroid morphology/gene expression. Furthermore, perchlorate exposure reduced liver Dio1 mRNA expression and increased the content of pro-inflammatory cytokines in the thyroid and the serum. In conclusion, our study adds novel findings about the perchlorate-induced disruption of the hypothalamus-pituitary-thyroid axis gene/protein expression in male rats. The data presented herein also suggest that perchlorate induces thyroid and systemic inflammation through the increased production of cytokines. Taken together, our results suggest that perchlorate contamination should be monitored, especially in the individuals most susceptible to the deleterious effects of reduced levels of thyroid hormones.

Primary thyroid-like low-grade nasopharyngeal papillary adenocarcinoma: A case report and literature review

RATIONALE

Primary thyroid-like low-grade nasopharyngeal papillary adenocarcinoma (TL-LGNPPA) is an extremely rare malignant nasopharyngeal tumor with features resembling papillary thyroid carcinoma including nuclear positive expression of thyroid transcription factor-1 (TTF-1).

PATIENT CONCERNS

A 64-year-old male presented with nasal bleeding and a foreign body sensation of the nasopharynx. Laryngoscopy revealed a 2.0-cm broad-based mass with a smooth surface on the posterior wall of the nasopharynx. A biopsy was obtained.

DIAGNOSES

Histopathologic examination demonstrated tumor cells arranged in both papillary and glandular architecture. The tumor cells express nuclear immunoreactivity for TTF-1. The diagnosis of TL-LGNPPA was made.

INTERVENTIONS

After the patient was diagnosed with TL-LGNPPA, he underwent complete surgical resection.

OUTCOMES

There was no recurrence or evidence of metastatic disease at the 12-month follow-up.

LESSONS

TL-LGNPPA is easy to misdiagnose as metastatic papillary thyroid carcinoma or other relative primary adenocarcinomas. It is important to have a broad differential diagnosis and know the key features of each entity because the prognosis and clinical treatment of each may differ.

Differentiation of Human Pluripotent Stem Cells into Functional Lung Alveolar Epithelial Cells

Lung alveoli, which are unique to air-breathing organisms, have been challenging to generate from pluripotent stem cells (PSCs) in part because there are limited model systems available to provide the necessary developmental roadmaps for in vitro differentiation. Here we report the generation of alveolar epithelial type 2 cells (AEC2s), the facultative progenitors of lung alveoli, from human PSCs. Using multicolored fluorescent reporter lines, we track and purify human SFTPC+ alveolar progenitors as they emerge from endodermal precursors in response to stimulation of Wnt and FGF signaling. Purified PSC-derived SFTPC+ cells form monolayered epithelial "alveolospheres" in 3D cultures without the need for mesenchymal support, exhibit self-renewal capacity, and display additional AEC2 functional capacities. Footprint-free CRISPR-based gene correction of PSCs derived from patients carrying a homozygous surfactant mutation (SFTPB121ins2) restores surfactant processing in AEC2s. Thus, PSC-derived AEC2s provide a platform for disease modeling and future functional regeneration of the distal lung.

Quantitative proteomics identify Tenascin-C as a promoter of lung cancer progression and contributor to a signature prognostic of patient survival

The extracellular microenvironment is an integral component of normal and diseased tissues that is poorly understood owing to its complexity. To investigate the contribution of the microenvironment to lung fibrosis and adenocarcinoma progression, two pathologies characterized by excessive stromal expansion, we used mouse models to characterize the extracellular matrix (ECM) composition of normal lung, fibrotic lung, lung tumors, and metastases. Using quantitative proteomics, we identified and assayed the abundance of 113 ECM proteins, which revealed robust ECM protein signatures unique to fibrosis, primary tumors, or metastases. These analyses indicated significantly increased abundance of several S100 proteins, including Fibronectin and Tenascin-C (Tnc), in primary lung tumors and associated lymph node metastases compared with normal tissue. We further showed that Tnc expression is repressed by the transcription factor Nkx2-1, a well-established suppressor of metastatic progression. We found that increasing the levels of Tnc, via CRISPR-mediated transcriptional activation of the endogenous gene, enhanced the metastatic dissemination of lung adenocarcinoma cells. Interrogation of human cancer gene expression data revealed that high TNC expression correlates with worse prognosis for lung adenocarcinoma, and that a three-gene expression signature comprising TNC, S100A10, and S100A11 is a robust predictor of patient survival independent of age, sex, smoking history, and mutational load. Our findings suggest that the poorly understood ECM composition of the fibrotic and tumor microenvironment is an underexplored source of diagnostic markers and potential therapeutic targets for cancer patients.

Prognostic impact of TTF-1 expression in patients with stage IV lung adenocarcinomas

OBJECTIVES

Thyroid transcription factor 1 (TTF-1) is routinely tested in the diagnostic evaluation of suspected lung cancers, is commonly expressed by lung adenocarcinomas, and may modulate lung cancer biology. We examined the role of TTF-1 as a predictive and prognostic marker in patients with advanced lung adenocarcinomas.

MATERIALS AND METHODS

We analyzed clinical, pathologic, and molecular features, treatments received, and overall survival obtained from the medical records of 479 consecutive patients at a single site with stage IV lung adenocarcinomas and evaluable TTF-1 expression. TTF-1 expression was determined by immunohistochemistry using antibody 8G7G3/1.

RESULTS AND CONCLUSION

TTF-1 expression was evaluable in 479 (75%) of all patients reviewed, and was positive in 383 (80%, 95% CI 76-83%). Clinicopathologic features were similar between TTF-1 positive and TTF-1 negative tumors, except EGFR mutations were more common in TTF-1 positive cases (24% vs 6%, p<0.001). In univariate analysis, overall survival was significantly longer in patients with TTF-1 positive versus TTF-1 negative tumors (18 months vs 9 months, p<0.0001). In multivariate analysis, TTF-1 positivity remained associated with better overall survival (HR=0.38, p<0.0001), exceeding the prognostic impact of Karnofsky performance status >/=80% (HR 0.62, p=0.0003) and receipt of first-line combination chemotherapy or targeted therapy (HR relative to first-line single agent chemotherapy 0.59, p=0.05 and 0.51, p=0.05 respectively). Both patients with TTF-1 positive and TTF-1 negative cancers had longer durations of initial therapy when treated with pemetrexed-based chemotherapy. In patients with advanced lung adenocarcinomas, TTF-1 expression is associated with better survival but is not predictive of distinct benefit from pemetrexed-based chemotherapy.

Mitral valve vegetation diagnosed with oesophageal ultrasound with bronchoscope (EUS-B)

Oesophageal ultrasound with bronchoscope (EUS-B) is designed to evaluate mediastinal structures. We describe a case of a 78-year-old woman who presented with altered mental status for 2 weeks. CT head revealed a subacute infarct in the right middle cerebral artery distribution. She was also found to have a lung mass on chest imaging. EUS-B-guided fine needle aspiration demonstrated the presence of adenocarcinoma in station 7 lymph node and in the mass. Immunohistochemistry confirmed it to be a lung primary as the Thyroid Transcription Factor-1 (TTF-1) was strongly positive. During the procedure, the cardiac valves were evaluated, and a mitral valve vegetation was noted. Formal echocardiography confirmed the presence of the vegetation. During hospital stay, the patient developed fever. Her blood cultures grew oxacillin-resistant Staphylococcus aureus. She was subsequently treated for infective endocarditis. We suggest that the use of EUS-B to routinely scan adjacent structures during a procedure may help obtain additional clinical information that may be critical to patient management.

An Adult Mouse Thyroid Side Population Cell Line that Exhibits Enriched Epithelial-Mesenchymal Transition

BACKGROUND

Studies of thyroid stem/progenitor cells have been hampered due to the small organ size and lack of tissue, which limits the yield of these cells. A continuous source that allows the study and characterization of thyroid stem/progenitor cells is desired to push the field forward.

METHOD

A cell line was established from Hoechst-resistant side population cells derived from mouse thyroid that were previously shown to contain stem/progenitor-like cells. Characterization of these cells were carried out by using in vitro two- and three-dimensional cultures and in vivo reconstitution of mice after orthotopic or intravenous injection, in conjunction with quantitative reverse transcription polymerase chain reaction, Western blotting, immunohisto(cyto)chemistry/immunofluorescence, and RNA seq analysis.

RESULTS

These cells were named SPTL (side population cell-derived thyroid cell line). Under low serum culturing conditions, SPTL cells expressed the thyroid differentiation marker NKX2-1, a transcription factor critical for thyroid differentiation and function, while no expression of other thyroid differentiation marker genes were observed. SPTL cells formed follicle-like structures in Matrigel^® cultures, which did not express thyroid differentiation marker genes. In mouse models of orthotopic and intravenous injection, the latter following partial thyroidectomy, a few SPTL cells were found in part of the follicles, most of which expressed NKX2-1. SPTL cells highly express genes involved in epithelial-mesenchymal transition, as demonstrated by RNA seq analysis, and exhibit a gene-expression pattern similar to anaplastic thyroid carcinoma.

CONCLUSION

These results demonstrate that SPTL cells have the capacity to differentiate into thyroid to a limited degree. SPTL cells may provide an excellent tool to study stem cells, including cancer stem cells of the thyroid.

Directed differentiation of basal forebrain cholinergic neurons from human pluripotent stem cells

BACKGROUND

Basal forebrain cholinergic neurons (BFCNs) play critical roles in learning, memory and cognition. Dysfunction or degeneration of BFCNs may connect to neuropathology, such as Alzheimer's disease, Down's syndrome and dementia. Generation of functional BFCNs may contribute to the studies of cell-based therapy and pathogenesis that is related to learning and memory deficits.

NEW METHOD

Here we describe a detail method for robust generation of BFCNs from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). In this method, BFCN progenitors are patterned from hESC or hiPSC-derived primitive neuroepithelial cells, with the treatment of sonic hedgehog (SHH) or combination with its agonist Purmorphamine, and by co-culturing with human astrocytes.

RESULTS

At day 20, ∼90% hPSC-derived progenitors expressed NKX2.1, which is a transcriptional marker for MGE. Moreover, around 40% of NKX2.1+ cells co-expressed OLIG2 and ∼15% of NKX2.1+ cells co-expressed ISLET1, which are ventral markers. At day 35, ∼40% neurons robustly express ChAT, most of which are co-labeled with NKX2.1, ISLET1 and FOXG1, indicating the basal forebrain-like identity. At day 45, these neurons express mature neuronal markers MAP2, Synapsin, and VAChT.

COMPARISON WITH EXISTING METHOD(S)

In this method, undefined conditions including genetic modification or cell-sorting are avoided. As a choice, feeder free conditions are used to avoid ingredients of animal origin. Moreover, Purmorphamine can be substituted for SHH to induce ventral progenitors effectively and economically.

CONCLUSION

We provide an efficient method to generate BFCNs from multiple hPSC lines, which offers the potential application for disease modeling and pharmacological studies.