Autophagy Inhibition Increased Sensitivity of Pancreatic Cancer Cells to Carbon Ion Radiotherapy.

BACKGROUND/AIMS: Pancreatic cancer has the poorest survival rate among all cancer types. Therefore, it is essential to develop an effective treatment strategy for this cancer. METHODS: We performed carbon ion radiotherapy (CIRT) in human pancreatic cancer cell lines and analyzed their survival, apoptosis, necrosis, and autophagy. To investigate the role of CIRT-induced autophagy, autophagy inhibitors were added to cells prior to CIRT. To evaluate tumor formation, we inoculated CIRT-treated murine pancreatic cancer cells on the flank of syngeneic mice and measured tumor weight. We immunohistochemically measured autophagy levels in surgical sections from patients with pancreatic cancer who received neoadjuvant chemotherapy (NAC) plus CIRT or NAC alone. RESULTS: CIRT reduced the survival fraction of pancreatic cancer cells and induced apoptotic and necrotic alterations, along with autophagy. Preincubation with an autophagy inhibitor accelerated cell death. Mice inoculated with control pancreatic cancer cells developed tumors, while those inoculated with CIRT/autophagy inhibitor-treated cells showed significant evasion. Surgical specimens of NAC-treated patients expressed autophagy comparable to control patients, while those in the NAC plus CIRT group expressed little autophagy and nuclear staining. CONCLUSION: CIRT effectively killed the pancreatic cancer cells by inhibiting their autophagy-inducing abilities.

Antithrombin Together with NETs Inhibitor Protected Against Postoperative Adhesion Formation in Mice.

BACKGROUND/AIMS: Postoperative adhesions may induce adverse outcomes in patients. Adhesion formation is initiated by fibrin accumulation at the surgical site which is followed by local neutrophilia and the establishment of neutrophil extracellular traps (NET). Previous reports have suggested that the preventive efficacy of reagents designed to reduce postoperative adhesion is inversely correlated with neutrophilia and NET production. Antithrombin (AT) is a natural inhibitor of thrombin, a key factor in coagulation. Here, we evaluate whether treatment with AT and/or NET inhibitors prevent or reduce postoperative adhesion formation in mice. METHODS: Mice were treated with AT and/or NET inhibitors before and/or after cecum cauterization and their adhesion scores were evaluated on day 7 post-operation. Immunochemistry/ immunofluorescence analyses were also performed and we used GSK484, an inhibitor of peptidyl arginine deiminase 4 (PAD4), as the NET inhibitor. RESULTS: AT or GSK484 partially rescued postoperative adhesion formation in mice. AT prevented thrombin-induced plasminogen activator inhibitor 1 and interleukin-6 expression in mesothelial cells in vitro. However, AT could not prevent neutrophilia or NETs formation around the injured serosa. Finally, we investigated a combination of AT and a PAD4 inhibitor and found that this could inhibit almost all adhesion formation in these animals. Since AT-inactivating proteases are liberated following NET release, they might dampen the biological action of the AT treatment. This suggests that NET inhibitors might allow AT to exert its full action in the surgically injured serosa. CONCLUSION: Combined treatment with AT and GSK484 may effectively attenuate postoperative adhesion production in mice.

Blockade of Tumor Necrosis Factor by Etanercept Prevents Postoperative Adhesion Formation in Mice.

BACKGROUND/AIMS: Although adhesion formation is a frequent adverse event following intraperitoneal surgery, efficient prophylactic interventions have not yet been established. We recently reported that blockade of interleukin (IL)-6 prevented postoperative adhesion after cecum cauterization. Intriguingly, this intervention dampened tumor necrosis factor (TNF) induction in the injured serosa. Herein, we addressed whether TNF might be a key target and, if so, how TNF blockade rescued adhesion formation. METHODS: Mice were administered an anti-TNF biologic (etanercept) on days -2 and -1 before and upon cecal cauterization. The adhesion scores were evaluated at day 7 postoperatively. Histological alterations were examined by immunochemistry/immunofluorescence studies. We incubated human neutrophils and mesothelial cell line cells with recombinant TNF in the presence of etanercept and measured transcript levels of cytokines and chemokines by quantitative reverse transcription-polymerase chain reaction (RT-qPCR). RESULTS: Etanercept rescued mice from adhesion formation, accompanied by a robust reduction of neutrophilia in the injured serosa. Immunofluorescence revealed a substantial formation of neutrophil extracellular traps (NETs) with the potential to induce tissue damage and profibrotic responses. In contrast, the etanercept-treated mice lacked NET formation. In addition, etanercept inhibited TNF-induced IL-6, TNF, and neutrophil-recruiting chemokines in neutrophils and mesothelial cells, a major cellular source of myofibroblasts in the adhesion band. CONCLUSION: Prophylactic administration of etanercept might be a potential strategy for preventing postoperative adhesion formation.

Clinicopathological effect of PLAG1 fusion genes in pleomorphic adenoma and carcinoma ex pleomorphic adenoma with special emphasis on histological features.

AIMS: Pleomorphic adenoma gene 1 (PLAG1) rearrangement is well known in pleomorphic adenoma (PA), which is histologically characterised by admixed epithelial and mesenchymal components. Multiple fusion variants of PLAG1 and HMGA2 have been reported; currently, however, little is known regarding the clinicopathological impacts of these fusion types METHODS AND RESULTS: We examined the PLAG1- and HMGA2-related fusion status in 105 PAs and 11 cases of carcinoma ex PAs (CXPA) arising from salivary glands and lacrimal glands to elucidate their correlation to the clinicopathological factors. Forty cases harboured PLAG1 fusion genes: CTNNB1-PLAG1 in 22 cases, CHCHD7-PLAG1 in 14 cases and LIFR-PLAG1 in four cases. Only two cases possessed HMGA2 fusion genes. The mean age of LIFR-PLAG1-positive cases was significantly higher than that of CTNNB1-PLAG1- and CHCHD7-PLAG1-positive cases (P = 0.0358). PAs located in the submandibular gland demonstrated CTNNB1-PLAG1 fusion at a significantly higher rate than other fusions (P = 0.0109). Histologically, PLAG1 fusion-positive cases exhibited chondroid formation and plasmacytoid features more commonly (P = 0.043, P = 0.015, respectively) and myxoid abundant feature less frequently (P = 0.031) than PLAG1 fusion-negative cases. For CXPAs, four CTNNB1-PLAG1 fusions were detected in two salivary duct carcinomas and two myoepithelial carcinomas. Ductal formation was observed frequently (90.9%) in residual PA. CONCLUSIONS: The presence of PLAG1 fusion was associated with specific histological features in PA. Detecting the PLAG1 fusion gene and searching residual ductal formation in salivary gland malignant tumours with extensive hyalinisation could be useful for diagnosis.

Oxidized regenerated cellulose induces pleural thickening in patients with pneumothorax: possible involvement of the mesothelial-mesenchymal transition.

PURPOSE: The pleural covering technique, i.e., wrapping a part of or the entire surface of the lung with oxidized regenerative cellulose (ORC), reinforces visceral pleura through pleural thickening for patients with pneumothorax and cystic lung diseases. However, it remains undetermined how ORC induces pleural thickening. METHODS: A histopathological examination was performed for lung specimens from patients who had recurrent pneumothoraces after pleural covering and re-operation (n = 5). To evaluate the influence of ORC on the pleura in vitro, we used MeT-5A cells (a human pleural mesothelial cell line). RESULTS: Pleural thickening was confirmed in all lung specimens examined. Three months after covering, the thickened pleura showed inflammatory cell infiltration, proliferation of myofibroblasts, and expression of fibronectin and TGF-ß. However, after 1 year, those findings virtually disappeared, and the thickened pleura was composed mainly of abundant collagen. When MeT-5A cells were cultured in ORC-immersed medium, their morphology changed from a cobblestone to spindle-shaped appearance. The expression of E-cadherin decreased, whereas that of N-cadherin, α-smooth muscle actin, and fibronectin increased, suggesting mesothelial-mesenchymal transition (Meso-MT). CONCLUSIONS: Our results suggest that Meso-MT may be involved as a mechanism of pleural thickening induced by pleural covering with ORC.

Isolation of individual cellular components from lung tissues of patients with lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease entailing cystic destruction of the lungs and progressive respiratory failure. LAM lungs are histologically characterized by the proliferation of smooth muscle-like cells (LAM cells) and an abundance of lymphatic vessels. To elucidate the pathophysiological processes of LAM, cell-type-specific analyses are required. However, no method exists for isolating the individual types of cells in LAM lesions. Therefore, we established a fluorescence-activated cell sorting (FACS)-based method for the direct isolation of LAM cells and other various cellular components from LAM-affected lung tissue. We obtained LAM-affected lung tissue from resections or transplant recipients and prepared single-cell suspensions. FACS, immunohistochemical, and molecular analysis were used cooperatively to isolate HMB45-positive LAM cells with tuberous sclerosis complex (TSC) 2 loss of heterozygosity (LOH). Using a combination of antibodies against an epithelial cell adhesion molecule (EpCAM) and podoplanin, we fractionated CD45-negative lung cells into three groups: lymphatic endothelial cells (LEC) (EpCAM(-)/podoplanin(hi) subset), alveolar type II cells (EpCAM(hi)/podoplanin(-) subset), and mesenchymal cells (EpCAM(-)/podoplanin(-/low) subset). During subsequent analysis of HMB45 expression, as a LAM-specific marker, we clearly identified LAM cells in the mesenchymal cell population. We then discovered that CD90(+)/CD34(-) cells in the mesenchymal cell population are not only positive for HBM45 but also had TSC2 LOH. These isolated cells were viable and subsequently amenable to cell culture. This method enables us to isolate LAM cells and other cellular components, including LAM-associated LEC, from LAM-affected lung tissues, providing new research opportunities in this field.

Detection of low-prevalence somatic TSC2 mutations in sporadic pulmonary lymphangioleiomyomatosis tissues by deep sequencing.

Lymphangioleiomyomatosis (LAM) (MIM #606690) is a rare lung disorder leading to respiratory failure associated with progressive cystic destruction due to the proliferation and infiltration of abnormal smooth muscle-like cells (LAM cells). LAM can occur alone (sporadic LAM, S-LAM) or combined with tuberous sclerosis complex (TSC-LAM). TSC is caused by a germline heterozygous mutation in either TSC1 or TSC2, and TSC-LAM is thought to occur as a result of a somatic mutation (second hit) in addition to a germline mutation in TSC1 or TSC2 (first hit). S-LAM is also thought to occur under the two-hit model involving a somatic mutation and/or loss of heterozygosity in TSC2. To identify TSC1 or TSC2 changes in S-LAM patients, the two genes were analyzed by deep next-generation sequencing (NGS) using genomic DNA from blood leukocytes (n = 9), LAM tissue from lung (n = 7), LAM cultured cells (n = 4), or LAM cell clusters (n = 1). We identified nine somatic mutations in six of nine S-LAM patients (67 %) with mutant allele frequencies of 1.7-46.2 %. Three of these six patients (50 %) showed two different TSC2 mutations with allele frequencies of 1.7-28.7 %. Furthermore, at least five mutations with low prevalence (<20 % of allele frequency) were confirmed by droplet digital PCR. As LAM tissues are likely to be composed of heterogeneous cell populations, mutant allele frequencies can be low. Our results confirm the consistent finding of TSC2 mutations in LAM samples, and highlight the benefit of laser capture microdissection and in-depth allele analyses for detection, such as NGS.

Clinicopathological effects of protein phosphatase 2, regulatory subunit A, alpha mutations in gastrointestinal stromal tumors.

Recently, several studies have reported that dysfunctions in protein phosphatase 2A (PP2A) caused by alterations in protein phosphatase 2 regulatory subunit A, alpha (PPP2R1A) are responsible for tumorigenesis and tumor progression in several types of cancers. The impact of PPP2R1A mutations remains unknown in gastrointestinal stromal tumors (GISTs), although mutations in KIT and PDGFRA, which result in constitutive activation of the receptor tyrosine kinase pathway, are important in GIST tumorigenesis. In this study, we performed mutation analysis of PPP2R1A to examine the frequency of PPP2R1A mutations and their clinicopathological correlation in 94 GIST cases. In addition, we performed an in vitro analysis to investigate the effects of PPP2R1A mutations on cell proliferation and kinase phosphorylation in GIST cells. Seventeen GIST cases (18%) harbored mutations in PPP2R1A. All but one of these 17 cases harbored a KIT, PDGFRA, HRAS, NRAS, or KRAS mutation as the oncogenic driver mutation, and the remaining case was immunohistochemically negative for succinate dehydrogenase B (SDHB). Multivariate analysis showed that larger tumor size, higher mitotic rate, and PPP2R1A mutation are independent prognostic factors for overall survival; however, PPP2R1A mutation was not an independent prognostic factor for disease-free survival. The transduction of GIST cells with mutant PPP2R1A induced an accelerated growth rate via increased phosphorylation of Akt1/2, ERK1/2, and WNK1, a kinase associated with angiogenesis. In addition, the transduction of GIST cells with mutant PPP2R1A caused increased c-kit phosphorylation, suggesting that c-kit is also a target of PP2A, reinforcing the tumorigenic capabilities of c-kit. Furthermore, the transducing GIST cells with wild-type PP2A dephosphorylated mutant c-kit. This study provides a new insight into the biology of GISTs and their phosphatase activity, and activated PP2A could be a therapeutic target in GISTs.

Benign clear cell "sugar" tumor of the lung in a patient with Birt-Hogg-Dubé syndrome: a case report.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome is a rare inherited autosomal genodermatosis and caused by germline mutation of the folliculin (FLCN) gene, a tumor suppressor gene of which protein product is involved in mechanistic target of rapamycin (mTOR) signaling pathway regulating cell growth and metabolism. Clinical manifestations in BHD syndrome is characterized by fibrofolliculomas of the skin, pulmonary cysts with or without spontaneous pneumothorax, and renal neoplasms. There has been no pulmonary neoplasm reported in BHD syndrome, although the condition is due to deleterious sequence variants in a tumor suppressor gene. Here we report, for the first time to our knowledge, a patient with BHD syndrome who was complicated with a clear cell "sugar" tumor (CCST) of the lung, a benign tumor belonging to perivascular epithelioid cell tumors (PEComas) with frequent causative relation to tuberous sclerosis complex 1 (TSC1) or 2 (TSC2) gene. CASE PRESENTATION: In a 38-year-old Asian woman, two well-circumscribed nodules in the left lung and multiple thin-walled, irregularly shaped cysts on the basal and medial area of the lungs were disclosed by chest roentgenogram and computer-assisted tomography (CT) during a preoperative survey for a bilateral faucial tonsillectomy. Analysis of the resected tumor showed large polygonal cells with clear cytoplasm proliferating in a solid pattern. Immunohistochemistry revealed that these tumor cells were positive for microphthalmia-transcription factor, S100, and CD1a but negative for HMB45, indicating that the tumor was a CCST. Genetic testing indicated that the patient had a germline mutation on exon 12 of the FLCN gene, i.e., insertion of 7 nucleotides (CCACCCT) (c.1347_1353dupCCACCCT). Direct sequencing of the FLCN exon 12 using genomic DNA obtained from her microdissected CCST cells clearly revealed loss of the wild-type FLCN sequence, which confirmed complete functional loss of the FLCN gene. On the other hand, no loss of heterozygosity around TCS1- or TSC2-associated genetic region was demonstrated. CONCLUSION: To our knowledge, this is the first report of CCST of the lung in a patient with BHDS, indicating that CCST should be added to the spectrum of pulmonary manifestations of BHDS.

Novel biomarkers that assist in accurate discrimination of squamous cell carcinoma from adenocarcinoma of the lung.

BACKGROUND: Targeted therapies based on the molecular and histological features of cancer types are becoming standard practice. The most effective regimen in lung cancers is different between squamous cell carcinoma (SCC) and adenocarcinoma (AD). Therefore a precise diagnosis is crucial, but this has been difficult, particularly for poorly differentiated SCC (PDSCC) and AD without a lepidic growth component (non-lepidic AD). Biomarkers enabling a precise diagnosis are therefore urgently needed. METHODS: Cap Analysis of Gene Expression (CAGE) is a method used to quantify promoter activities across the whole genome by determining the 5' ends of capped RNA molecules with next-generation sequencing. We performed CAGE on 97 frozen tissues from surgically resected lung cancers (22 SCC and 75 AD), and confirmed the findings by immunohistochemical analysis (IHC) in an independent group (29 SCC and 45 AD). RESULTS: Using the genome-wide promoter activity profiles, we confirmed that the expression of known molecular markers used in IHC for SCC (CK5, CK6, p40 and desmoglein-3) and AD (TTF-1 and napsin A) were different between SCC and AD. We identified two novel marker candidates, SPATS2 for SCC and ST6GALNAC1 for AD, as showing comparable performance and complementary utility to the known markers in discriminating PDSCC and non-lepidic AD. We subsequently confirmed their utility at the protein level by IHC in an independent group. CONCLUSIONS: We identified two genes, SPATS2 and ST6GALNAC1, as novel complemental biomarkers discriminating SCC and AD. These findings will contribute to a more accurate diagnosis of NSCLC, which is crucial for precision medicine for lung cancer.

PTCH1 mutation is a frequent event in oesophageal basaloid squamous cell carcinoma.

Basaloid squamous cell carcinoma (BSCC) is a rare and poorly differentiated variant of typical squamous cell carcinoma, and is characterised in part by activation of the Wnt signalling pathway. We previously demonstrated that constitutive activation of the Wnt signalling pathway by epigenetic silencing of secreted frizzled-related protein 4 (SFRP4) is observed in this tumour. Increasing evidence shows that the Wnt signalling pathway cross-talks with other developmental pathways, including the Hedgehog (HH) pathway. The HH pathway is stimulated by inactivating mutations of PTCH1, which have a well-described oncogenic role in basal cell carcinoma (BCC) of the skin. We employed polymerase chain reaction followed by direct sequencing to detect inactivating mutations of PTCH1 using archival tissue samples of 30 oesophageal BSCCs. The frequency of PTCH1 mutation was compared to that of Wnt component genes that we reported previously. We found PTCH1 mutations in 53.3% (16/30) of cases, revealing T1195S as a hotspot mutation. This frequency is quite high for cancers other than BCC of the skin, and PTCH1 mutations were almost mutually exclusive with mutations in APC, Axin1 and Axin2. Considering the fact that activation of Wnt signalling via down-regulation of APC and SFRP5 due to promoter methylation is observed in BCC of the skin, Wnt signalling activation in oesophageal BSCC might be a secondary effect of the PTCH1-inactivating mutations. These findings suggest that the HH and Wnt pathways coordinately contribute to tumourigenesis in oesophageal BSCC. Furthermore, this study provides a potential therapeutic application for HH pathway inhibitors in oesophageal BSCC with highly malignant potential.

Characterization of pulmonary cysts in Birt-Hogg-Dubé syndrome: histopathological and morphometric analysis of 229 pulmonary cysts from 50 unrelated patients.

AIMS: To characterize the pathological features of pulmonary cysts, and to elucidate the possible mechanism of cyst formation in the lungs of patients with Birt-Hogg-Dubé syndrome (BHDS), a tumour suppressor gene syndrome, using histological and morphometric analyses. METHODS AND RESULTS: We evaluated 229 lung cysts from 50 patients with BHDS and 117 from 34 patients with primary spontaneous pneumothorax (PSP) for their number, size, location and absence or presence of inflammation. The BHDS cysts abutted on interlobular septa (88.2%) and had intracystic septa (13.6%) or protruding venules (39.5%) without cell proliferation or inflammation. The frequencies of these histological characteristics differed significantly from those seen in the lungs of patients with PSP (P < 0.05). Although the intrapulmonary BHDS cysts were smaller than the subpleural BHDS cysts (P < 0.001), there was no difference in size between them when there was no inflammation. The number of cysts diminished logarithmically and the proportion of cysts with inflammation increased as their individual sizes became greater (P < 0.05). CONCLUSIONS: These results imply that the BHDS cysts are likely to develop in the periacinar region, an anatomically weak site in a primary lobule, where alveoli attach to connective tissue septa. We hypothesize that the BHDS cysts possibly expand in size as the alveolar walls disappear at the alveolar-septal junction, and grow even larger when several cysts fuse.

Clinicopathological Impacts of Expression of Neuronal Markers in Lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a tuberous sclerosis complex (TSC)-associated tumor, characterized by the expression of neural crest lineages including neuronal markers. Neural crest cells can differentiate into multiple cell types that contribute to tissues associated with TSC-related tumors, and TSC-related tumors could be specifically associated with distinct neural crest subtypes. This study aimed to clarify the clinicopathological effects of expression of neuronal markers in LAM. Lung tissues from 40 patients with LAM (of whom 13, 1, and 26 had undergone lung transplantation, lobectomy, and partial lung resection, respectively) were immunohistochemically analyzed. All patients were women, and their median age was 36 years (range: 24-62 y). All patients who underwent lung transplantation or lobectomy were classified as LAM histologic score (LHS)-3, whereas those who underwent partial lung resection were classified as LHS-1. LAM cells expressed peripherin (65%), and neuron-specific ßIII-tubulin (43%). A comparison of the early (LHS-1) and advanced (LHS-3) stages of LAM revealed that neuron-specific ßIII-tubulin was significantly expressed in the early stage of LAM ( P = 0.0009). Neuron-specific ßIII-tubulin-positive LAM was associated with younger age ( P < 0.0001), the coexistence of renal angiomyolipoma ( P = 0.027), and the absence of retroperitoneal LAM ( P = 0.045). Furthermore, based on the expression levels of immunohistochemical markers in LAM, 2 distinct clusters with different expression levels of neuronal markers were observed. Approximately 40% to 60% of patients with LAM expressed neuron-specific ßIII-tubulin and peripherin. Neuronal expression may be associated with disease severity.

Isolation and characterisation of lymphatic endothelial cells from lung tissues affected by lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare pulmonary disease characterised by the proliferation of smooth muscle-like cells (LAM cells), and an abundance of lymphatic vessels in LAM lesions. Studies reported that vascular endothelial growth factor-D (VEGF-D) secreted by LAM cells contributes to LAM-associated lymphangiogenesis, however, the precise mechanisms of lymphangiogenesis and characteristics of lymphatic endothelial cells (LECs) in LAM lesions have not yet been elucidated. In this study, human primary-cultured LECs were obtained both from LAM-affected lung tissues (LAM-LECs) and normal lung tissues (control LECs) using fluorescence-activated cell sorting (FACS). We found that LAM-LECs had significantly higher ability of proliferation and migration compared to control LECs. VEGF-D significantly promoted migration of LECs but not proliferation of LECs in vitro. cDNA microarray and FACS analysis revealed the expression of vascular endothelial growth factor receptor (VEGFR)-3 and integrin α9 were elevated in LAM-LECs. Inhibition of VEGFR-3 suppressed proliferation and migration of LECs, and blockade of integrin α9 reduced VEGF-D-induced migration of LECs. Our data uncovered the distinct features of LAM-associated LECs, increased proliferation and migration, which may be due to higher expression of VEGFR-3 and integrin α9. Furthermore, we also found VEGF-D/VEGFR-3 and VEGF-D/ integrin α9 signaling play an important role in LAM-associated lymphangiogenesis.

Uncommon radiologic computed tomography appearances of the chest in patients with lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare destructive lung disease characterized by multiple thin-walled pulmonary cysts. The currently proposed diagnostic algorithm emphasizes the characteristic cystic appearance on high-resolution computed tomography (HRCT) so uncommon HRCT appearances present challenges to establishing the proper LAM diagnosis. The objective of this study is to accrue uncommon chest HRCT appearances, determine frequencies in both tuberous sclerosis complex (TSC)-associated LAM (TSC-LAM) and sporadic LAM (S-LAM) patients. 311 females referred to our hospital, including 272 S-LAM patients (mean age 39.2 years) and 39 TSC-LAM patients (mean age 38.3 years), were retrospectively evaluated. We found 2 types of radiologic findings likely to make HRCT cyst appearance atypical: characteristics of the cyst itself and uncommon findings in addition to cysts. We found that approximately 80% of LAM patients, whether TSC-associated or sporadic, showed typical HRCT appearance with mild to severe cystic destruction. The remaining 20% displayed unusual profiles in cyst appearance as well as additional findings aside from cyst: the former includes large cyst, thickened walls, and irregularly shaped whereas the latter includes ground glass attenuation and diffuse noncalcified nodules. It is important to be aware of various radiologic findings that make HRCT cystic appearance atypical of LAM.

Folliculin haploinsufficiency causes cellular dysfunction of pleural mesothelial cells.

Birt-Hogg-Dubé syndrome (BHDS), an autosomal dominant inheritance disease caused by folliculin (FLCN) mutations, is associated with lung cysts and spontaneous pneumothorax. The possibility of FLCN haploinsufficiency in pleural mesothelial cells (PMCs) contributing to development of pneumothorax has not yet been clarified. Electron microscopy revealed exposed intercellular boundaries between PMCs on visceral pleura and decreased electron density around the adherens junctions in BHDS. To characterize cellular function of PMCs in BHDS patients (BHDS-PMCs), during surgery for pneumothorax, we established the flow cytometry-based methods of isolating high-purity PMCs from pleural lavage fluid. BHDS-PMCs showed impaired cell attachment and a significant decrease in proliferation and migration, but a significant increase in apoptosis compared with PMCs from primary spontaneous pneumothorax (PSP) patients (PSP-PMCs). Microarray analysis using isolated PMCs revealed a significant alteration in the expression of genes belonging to Gene Ontology terms "cell-cell adhesion junction" and "cell adhesion molecule binding". Gene set enrichment analysis demonstrated that CDH1, encoding E-cadherin, was identified in the down-regulated leading edge of a plot in BHDS-PMCs. AMPK and LKB1 activation were significantly impaired in BHDS-PMCs compared with PSP-PMCs. Our findings indicate that FLCN haploinsufficiency may affect the E-cadherin-LKB1-AMPK axis and lead to abnormal cellular function in BHDS-PMCs.

Loss of heterozygosity on tuberous sclerosis complex genes in multifocal micronodular pneumocyte hyperplasia.

Multifocal micronodular pneumocyte hyperplasia is a rare pulmonary manifestation of tuberous sclerosis complex (TSC) that is a tumor suppressor gene disorder characterized by many hamartomas. A purported mechanism of hamartomatous proliferation in TSC is constitutive activation of the mammalian target of rapamycin (mTOR) signaling pathway dysregulated by a functional loss of TSC genes. Although multifocal micronodular pneumocyte hyperplasia develops locally as self-limited, benign lesions, it is morphologically similar to the preinvasive lesion of pneumocytes that characterize atypical adenomatous hyperplasia or bronchioloalveolar carcinoma. Frequently both conditions include a loss of heterozygosity on TSC. The goal of this study was to determine whether multifocal micronodular pneumocyte hyperplasia is neoplastic. Loss of heterozygosity on TSC genes and immunohistochemistry for mTOR-related proteins (phospho-mTOR, phospho-p70S6K, phospho-S6, and phospho-Akt) were analyzed in 42 lesions: 16 multifocal micronodular pneumocyte hyperplasia (7 patients with TSC, 1 TSC not confirmed), 14 atypical adenomatous hyperplasia, and 12 bronchioloalveolar carcinoma (9 and 12 patients, respectively). The results showed that at least one of two multifocal micronodular pneumocyte hyperplasia lesions from each patient had loss of heterozygosity on TSC1 or TSC2 (15 or 50%) and were frequently immunopositive for phospho-mTOR (88%), phospho-p70S6K (100%), and phospho-S6 (100%) but not phospho-Akt (14%), an upstream regulatory protein of mTOR. Loss of heterozygosity of TSC was found in the preinvasive lesions of pneumocytes, equal to or less than multifocal micronodular pneumocyte hyperplasia. In contrast, phospho-Akt was expressed in the preinvasive lesions of pneumocytes more frequently than multifocal micronodular pneumocyte hyperplasia, but the other mTOR-related proteins were less frequently expressed in the former than in the latter. These outcomes suggest that functional loss of TSCs and consequent hyperphosphorylation of mTOR-related proteins in multifocal micronodular pneumocyte hyperplasia may cause its benign neoplastic proliferation of pneumocytes.

A case of Birt-Hogg-Dubé syndrome implying reduced or no wild-type folliculin without mutated protein is pathogenic.

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant cancer syndrome caused by a germline mutation of the folliculin (FLCN) gene. Previous studies have suggested that truncated mutant folliculin proteins generated by disease causing FLCN mutations may retain partial functionality and contribute to disease phenotype. A 38-year-old Russian man presented with a left renal tumor. He underwent a left radical nephrectomy and histological examination confirmed the diagnosis of chromophobe renal cell carcinoma. He had papulae on his face suggestive of fibrofolliculomas, and pulmonary cysts on his computed tomography of the chest. He had a family history of skin manifestations. Genetic analysis identified a genomic deletion including the putative promoter region of FLCN exon 1 in the germline, and the second hit on the remaining wild-type FLCN in the renal carcinoma cells, which is expected to cause the complete lack of folliculin protein. Immunohistochemistry with the use of anti-folliculin antibody showed no antibody-binding on chromophobe renal carcinoma cells. These findings suggest that the decreased FLCN expression itself without producing mutated folliculin proteins can be at risk for developing clinical manifestations of BHDS: fibrofolliculomas, lung cysts, and tumorigenesis in the kidneys. This sheds light on the pathogenesis of BHDS and the role of FLCN as a tumor suppressor gene.

Contribution of TIR domain-containing adapter inducing IFN-beta-mediated IL-18 release to LPS-induced liver injury in mice.

BACKGROUND/AIMS: After treatment with heat-killed Propionibacterium acnes mice show dense hepatic granuloma formation. Such mice develop liver injury in an interleukin (IL)-18-dependent manner after challenge with a sublethal dose LPS. As previously shown, LPS-stimulated Kupffer cells secrete IL-18 depending on caspase-1 and Toll-like receptor (TLR)-4 but independently of its signal adaptor myeloid differentiation factor 88 (MyD88), suggesting importance of another signal adaptor TIR domain-containing adapter inducing IFN-beta (TRIF). Nalp3 inflammasome reportedly controls caspase-1 activation. Here we investigated the roles of MyD88 and TRIF in P. acnes-induced hepatic granuloma formation and LPS-induced caspase-1 activation for IL-18 release. METHODS: Mice were sequentially treated with P. acnes and LPS, and their serum IL-18 levels and liver injuries were determined by ELISA and ALT/AST measurement, respectively. Active caspase-1 in LPS-stimulated Kupffer cells was determined by Western blotting. RESULTS: Macrophage-ablated mice lacked P. acnes-induced hepatic granuloma formation and LPS-induced serum IL-18 elevation and liver injury. Myd88(-/-) Kupffer cells, but not Trif(-/-) cells, exhibited normal caspase-1 activation upon TLR4 engagement in vitro. Myd88(-/-) mice failed to develop hepatic granulomas after P. acnes treatment and liver injury induced by LPS challenge. In contrast, Trif(-/-) mice normally formed the hepatic granulomas, but could not release IL-18 or develop the liver injury. Nalp3(-/-) mice showed the same phenotypes of Trif(-/-) mice. CONCLUSIONS: Propionibacterium acnes treatment MyD88-dependently induced hepatic granuloma formation. Subsequent LPS TRIF-dependently activated caspase-1 via Nalp3 inflammasome and induced IL-18 release, eventually leading to the liver injury.

Urothelial carcinoma of the renal pelvis with rhabdoid features.

Reported herein is the case of a 70-year-old man with high grade urothelial carcinoma (UC) with rhabdoid features of the renal pelvis. For the most part, the tumor was composed of pleomorphic, non-cohesive round tumor cells with abundant cytoplasm. In situ high-grade UC composed of cohesive tumor cells was seen only in a small portion. Pleomorphic dyscohesive tumor cells often showed rhabdoid features, containing eosinophilic inclusions. These pleomorphic/rhabdoid tumor cells were immunohistochemically positive for vimentin but negative for cytokeratins, CD45, CD20, CD79a, CD3, CD45RO, CD38, and CD138. Loss of heterozygosity (LOH) analysis demonstrated identical allelic losses as well as additional allelic losses for the dyscohesive and cohesive UC lesion, indicating that these two lesions originated from a single clonal lesion.