D2-40 labeling in lymphangiomyoma/lymphangiomyomatosis of the soft tissue: further evidence of lymphangiogenic tumor histogenesis

Podoplanin (PDPN) affects the invasiveness of thyroid carcinoma cells by inducing ezrin, radixin and moesin (E/R/M) phosphorylation in association with matrix metalloproteinases

Background

Podoplanin (PDPN) is a mucin-type transmembrane glycoprotein specific to the lymphatic system. PDPN expression has been found in various human tumors and is considered to be a marker of cancer. We had previously shown that PDPN expression contributes to carcinogenesis in the TPC1 papillary thyroid cancer-derived cell line by enhancing cell migration and invasiveness. The aim of this study was to determine the effect of PDPN down-regulation in another thyroid cancer-derived cell line: BcPAP.

Methods

In order to determine the effects of PDPN on malignant features of BcPAP cells (harboring the BRAFV600E mutated allele) and TPC1 cells (carrying the RET/PTC1 rearrangement), we silenced PDPN in these cells using small interfering RNA (siRNA). The efficacy of PDPN silencing was confirmed by qRT-PCR and Western blotting. Then, we tested the motility and invasiveness of these cells (using scratch test and Transwell assay), their growth capacities F(cell cycle analysis, viability, clonogenic activity) and apoptosis assays), adhesion-independent colony-formation capacities, as well as the effect of PDPN silencing on MMPs expression and activity (zymography).

Results

We found that PDPN-induced cell phenotype depended on the genetic background of thyroid tumor cells. PDPN down-regulation in BcPAP cells was negatively correlated with the migration and invasion, in contrast to TPC1 cells in which PDPN depletion resulted in enhanced migration and invasiveness. Moreover, our results suggest that in BcPAP cells, PDPN may be involved in the epithelial-mesenchymal transition (EMT) through regulating the expression of the ezrin, radixin and moesin (E/R/M) proteins, MMPs 9 and MMP2, remodeling of actin cytoskeleton and cellular protrusions. We also demonstrated that PDPN expression is associated with the MAPK signaling pathway. The inhibition of the MAPK pathway resulted in a decreased PDPN expression, increased E/R/M phosphorylation and reduced cell migration. Additionally, PDPN depleted BcPAP cells treated with inhibitors of MEK1/2 kinases (U0126) or of the BRAF V600E protein (PLX4720) had reduced motility, similar to that previously observed in TPC1 cells after PDPN knock-down.

Conclusions

Altogether, our data suggest that PDPN may play an important role in the control of invasion and migration of papillary thyroid carcinoma cells in association with the E/R/M, MMPs and MAPK kinases.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5239-z) contains supplementary material, which is available to authorized users.

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.

The role of podoplanin in the biology of differentiated thyroid cancers

Podoplanin (PDPN), a mucin-type transmembrane glycoprotein specific to the lymphatic system is expressed in a variety of human cancers, and is regarded as a factor promoting tumor progression. The purpose of this study was to elucidate the molecular role of PDPN in the biology of thyroid cancer cells. PDPN expression was evaluated in primary thyroid carcinomas and thyroid carcinoma cell lines by RT-qPCR, Western blotting, IF and IHC. To examine the role of podoplanin in determining a cell's malignant potential (cellular migration, invasion, proliferation, adhesion, motility, apoptosis), a thyroid cancer cell line with silenced PDPN expression was used. We observed that PDPN was solely expressed in the cancer cells of 40% of papillary thyroid carcinoma (PTC) tissues. Moreover, PDPN mRNA and protein were highly expressed in PTC-derived TPC1 and BcPAP cell lines but were not detected in follicular thyroid cancer derived cell lines. PDPN knock-down significantly decreased cellular invasion, and modestly reduced cell migration, while proliferation and adhesion were not affected. Our results demonstrate that PDPN mediates the invasive properties of cells derived from papillary thyroid carcinomas, suggesting that podoplanin might promote PTC progression.

Angiosarcoma: a tissue microarray study with diagnostic implications

BACKGROUND

Angiosarcoma (AS) is a rare soft tissue sarcoma showing endothelial differentiation as indicated by morphology and expression of CD31 (blood), D2-40 (lymphatic), factor VIII, and CD34 (both). We sought to examine the pattern of immunohistochemical markers of differentiation in AS and correlate these with outcome.

DESIGN

An AS tissue microarray (n = 70 specimens) was constructed for immunohistochemical analysis of CD31, CD34, factor VIII, D2-40, and pan-cytokeratin. Samples on this array were linked to clinicopathologic and outcome data for these patients. Univariate analyses were used to explore disease-specific survival (DSS) factors.

RESULTS

Nine metastatic, 23 localized, and 4 recurrent cases were included. Information about the tissue status (ie, primary or metastasis) was unavailable in 4 patients. Primary sites for the tumor included bone (n = 1), breast parenchyma (n = 11), breast skin (n = 4), heart (n = 5), skin (n = 8), soft tissue (n = 7), and unknown (n = 3). Three patients presented with multifocal disease (primary sites in these patients included breast, skin, and soft tissue). Metastatic sites included lung, bone, lymph nodes, brain, liver, and parotid. Of the 40 cases, 8 (20%) showed a pure or predominant epithelioid histology. Of the biomarkers evaluated by tissue microarray, 92% of tumors expressed at least one endothelial marker (factor VIII = 83%, CD31 = 80%, CD34 = 63%, and D2-40 = 43%) with 88% expressing 2 or more markers. Eighty-eight percent of tumors expressing D2-40 coexpressed CD31, an unusual combination in normal vessels. No endothelial marker clearly associated with disease-specific survival. Fifty percent (4/8) of epithelioid cases and 9% (3/32) of nonepithelioid cases showed keratin expression.

CONCLUSIONS

Unusual patterns and loss of endothelial markers are common in AS, suggesting use of multiple markers in challenging cases and perhaps indicating important biologic characteristics.

Lymphatic endothelial differentiation in pulmonary lymphangioleiomyomatosis cells

Pulmonary lymphangioleiomyomatosis (LAM) is a rare, low-grade neoplasm affecting almost exclusively women of childbearing age. LAM belongs to the family of perivascular epithelioid cell tumors, characterized by spindle and epithelioid cells with smooth muscle and melanocytic differentiation. LAM cells infiltrate the lungs, producing multiple, bilateral lesions rich in lymphatic channels and forming cysts, leading to respiratory insufficiency. Here we used antibodies against four lymphatic endothelial markers-podoplanin (detected by D2-40), prospero homeobox 1 (PROX1), vascular endothelial growth factor receptor 3 (VEGFR-3), and lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1)-to determine whether LAM cells show lymphatic differentiation. Twelve of 12 diagnostic biopsy specimens (early-stage LAM) and 19 of 19 explants (late-stage LAM) showed immunopositivity for D2-40 in most neoplastic cells. PROX1, VEGFR-3, and LYVE1 immunoreactivity varied from scarce in the early stage to abundant in the late stage. Lymphatic endothelial, smooth muscle, and melanocytic markers were partially co-localized. These findings indicate that lymphatic endothelial differentiation is a feature of LAM and provide evidence of a previously unidentified third lineage of differentiation in this neoplasm. This study has implications for the histological diagnosis of LAM, the origin of the neoplastic cells, and potential future treatment with drugs targeting lymphangiogenesis.

Lymphatics in lymphangioleiomyomatosis and idiopathic pulmonary fibrosis

The primary function of the lymphatic system is absorbing and transporting macromolecules and immune cells to the general circulation, thereby regulating fluid, nutrient absorption and immune cell trafficking. Lymphangiogenesis plays an important role in tissue inflammation and tumour cell dissemination. Lymphatic involvement is seen in lymphangioleiomyomatosis (LAM) and idiopathic pulmonary fibrosis (IPF). LAM, a disease primarily affecting females, involves the lung (cystic destruction), kidney (angiomyolipoma) and axial lymphatics (adenopathy and lymphangioleiomyoma). LAM occurs sporadically or in association with tuberous sclerosis complex (TSC). Cystic lung destruction results from proliferation of LAM cells, which are abnormal smooth muscle-like cells with mutations in the TSC1 or TSC2 gene. Lymphatic abnormalities arise from infiltration of LAM cells into the lymphatic wall, leading to damage or obstruction of lymphatic vessels. Benign appearing LAM cells possess metastatic properties and are found in the blood and other body fluids. IPF is a progressive lung disease resulting from fibroblast proliferation and collagen deposition. Lymphangiogenesis is associated with pulmonary destruction and disease severity. A macrophage subset isolated from IPF bronchoalveolar lavage fluid (BALF) express lymphatic endothelial cell markers in vitro, in contrast to the same macrophage subset from normal BALF. Herein, we review lymphatic involvement in LAM and IPF.

Immunohistochemical endothelial markers: a review

A relatively large number of new endothelial markers that can assist in the diagnosis and classification of endothelial and vascular neoplasms have become available over the past few years. The expression of these markers, however, differs considerably among the various tumors. A selection of markers that have potential diagnostic utility or are of current interest among pathologists are reviewed and compared with some of the more traditional markers that have been employed in diagnostic pathology.

Immunohistochemical analysis of oral dysplasia: diagnostic assessment by fascin and podoplanin expression

The aim of this study was to investigate fascin and podoplanin expression in oral dysplasia and carcinoma in situ (CIS) immunohistochemically, and to evaluate their relationship to histopathological diagnosis based on architectural and cytological features. Fascin and podoplanin expression patterns were analyzed immunohistologically in 26 specimens of oral lesions, including benign disease (hyperplasia, papilloma, and others), intraepithelial neoplasia/borderline disease (dysplasia), and malignant disease (CIS, invasive squamous cell carcinoma). Fascin expression was scored into four original categories, and podoplanin expression was scored into five previously established categories. The relationship between the immunohistochemically determined scores of fascin and podoplanin expression and the architectural and cytological features in the hematoxylin-eosin-stained slides was analyzed statistically. The immunostaining scores for fascin and podoplanin were significantly higher in dysplasia and CIS than in benign disease (p=0.0011, p=0.00036), and they were significantly higher in dysplasia than in benign disease (p=0.0087, p=0.0032). In all cases of invasive SCC, fascin was expressed mainly in the cytoplasm of the tumor cells and fascin expression extended from the destruction of the basal layer of the epithelium to the upper layer of the epithelium and podoplanin was expressed in the cytoplasm and membrane of the tumor cells. This was the first report of up-regulation of fascin in oral dysplasia. Our results suggest that it would be helpful for improving the diagnostic accuracy of oral dysplasia and CIS to assess the expression of fascin and podoplanin immunohistochemically.

Expression of podoplanin in Warthin tumours

PURPOSE

Warthin tumour is the second most common benign tumour of the parotid gland. This study was designed to investigate the lymphatic vessels in Warthin tumours in an effort to understand better its pathogenesis.

MATERIALS AND METHODS

Tissue specimens of 31 patients (19 men and 11 women; mean age 57 years, median size of the tumours 2.86 cm) were analysed by means of immunohistochemistry applying the monoclonal antibody D2-40.

RESULTS

We found numerous D2-40-positive sinus-like vessels particularly at the inner layer of the capsule.

CONCLUSIONS

Since subcapsular sinuses are a major morphological feature of lymph nodes in general, the finding of podoplanin expression in the large majority of subcapsular vessels in Warthin tumours confirms the view that this tumour has its origin in regional lymph nodes.

Pulmonary lymphangioleiomyomatosis: unusual manifestations of multiple large pulmonary nodules with retroperitoneal lymph node involvement mimicking metastatic malignancy

Pulmonary lymphangioleiomyomatosis (LAM) is a rare, idiopathic disorder that predominantly affects the lung parenchyma of women of childbearing age. While the characteristic radiographic finding of pulmonary LAM consists of multiple well-defined thin-walled cysts, we describe a very unusual case of pulmonary LAM with multiple bilateral large pulmonary nodules and retroperitoneal involvement mimicking metastatic malignancy. A 48-year-old woman who had never smoked with a history of bilateral pneumothorax presented with progressive exertional dyspnea and abdominal discomfort. Imaging studies revealed multiple enlarged retroperitoneal lymph nodes, ascites and bilateral multiple large pulmonary nodules ranging from 3 to 18 mm in diameter. Exploratory laparoscopic surgery for intra-abdominal lesions and video-assisted thoracoscopic wedge resection of lung nodules were carried out to rule out metastatic malignancy. Pathology showed benign looking smooth muscle cell proliferation and immunoreactivity for α-smooth muscle actin and HMB-45 in both specimens. After treatment with GnRH antagonist, the patient was well over a 6-month period without evidence of disease progression.

Podoplanin expression in fibrous histiocytomas and cellular neurothekeomas

Podoplanin, also recognized by the monoclonal antibody D2-40, is a mucin-type transmembrane glycoprotein that is highly expressed in lymphatics and in a range of vascular and nonvascular proliferations. Recently, podoplanin has been detected in fibrous histiocytomas (FHs) and proposed to represent a potentially useful marker in the diagnostic evaluation of this lesion. There is, however, limited data concerning podoplanin expression in FH and its morphological mimics. Cellular neurothekeomas (CNs) are rare cutaneous neoplasms of uncertain histogenesis that often morphologically mimic FH. In this study, we reviewed our experience with podoplanin expression in FH (n = 30), especially in comparison to CN (n = 15). In addition, we also immunostained a selected group of other mesenchymal lesions that may fall within the differential diagnosis of FH for podoplanin, including dermal nerve sheath myxoma (n = 2), dermatofibrosarcoma protuberans (N = 8), and plexiform fibrohistiocytic tumor (n = 2). Podoplanin expression was observed in a significant subset of FHs (26/30, 86.6%) and in all CNs (15/15, 100%), whereas DFSPs, dermal nerve sheath myxomas, and plexiform fibrohistiocytic tumors were all negative. To the best of our knowledge, this is the first report demonstrating podoplanin expression in CN. Expression of podoplanin in CN represents a potential pitfall in the use of this antibody for diagnostic evaluation of FH. However, podoplanin may be of value as an adjunct to morphological examination in assessment of problematic lesions falling within the differential diagnosis of FH and CN.

A leiomyomatoid angiomatous neuroendocrine tumor of the myometrium: case study with ultrastructural analysis

Leiomyomatoid angiomatous neuroendocrine tumor (LANT) is a possible new disease entity that was described as a dimorphic neurosecretory tumor with a leiomyomatous vascular component; it was found in the pituitary. We describe here a second case of LANT in a 45-year-old woman with a myometrial tumor, diagnosed clinically as uterine leiomyoma. She underwent laparoscopic myomectomy. The tumor consisted of hyalinized vasculature, containing factor VIII-positive endothelium and smooth muscle actin-positive vascular smooth muscle cells, and stromal cells, expressing neuroadhesion molecules. Both vascular and stromal components diffusely expressed chromogranin A and, as evidenced by electron microscopy, possessed smooth muscle actin filaments and electron-dense neurosecretory granules, which contained the neurosecretory hormone somatostatin. Although no cytokeratin-positive cells were observed, some tumor cells had positive Grimelius staining for argyrophilic granules. These findings meet the definition of LANT, and the occurrence of our case suggests that LANT is a special type of neuroendocrine neoplasm and is not organ specific.