Outer Layer Of Myoepithelial Cells Research Articles

Peroxidasin Enhances Basal Phenotype and Inhibits Branching Morphogenesis in Breast Epithelial Progenitor Cell Line D492

The human breast is composed of terminal duct lobular units (TDLUs) that are surrounded by stroma. In the TDLUs, basement membrane separates the stroma from the epithelial compartment, which is divided into an inner layer of luminal epithelial cells and an outer layer of myoepithelial cells. Stem cells and progenitor cells also reside within the epithelium and drive a continuous cycle of gland remodelling that occurs throughout the reproductive period. D492 is an epithelial cell line originally isolated from the stem cell population of the breast and generates both luminal and myoepithelial cells in culture. When D492 cells are embedded into 3D reconstituted basement membrane matrix (3D-rBM) they form branching colonies mimicking the TDLUs of the breast, thereby providing a well-suited in vitro model for studies on branching morphogenesis and breast development. Peroxidasin (PXDN) is a heme-containing peroxidase that crosslinks collagen IV with the formation of sulfilimine bonds. Previous studies indicate that PXDN plays an integral role in basement membrane stabilisation by crosslinking collagen IV and as such contributes to epithelial integrity. Although PXDN has been linked to fibrosis and cancer in some organs there is limited information on its role in development, including in the breast. In this study, we demonstrate expression of PXDN in breast epithelium and stroma and apply the D492 cell line to investigate the role of PXDN in cell differentiation and branching morphogenesis in the human breast. Overexpression of PXDN induced basal phenotype in D492 cells, loss of plasticity and inhibition of epithelial-to-mesenchymal transition as is displayed by complete inhibition of branching morphogenesis in 3D culture. This is supported by results from RNA-sequencing which show significant enrichment in genes involved in epithelial differentiation along with significant negative enrichment of EMT factors. Taken together, we provide evidence for a novel role of PXDN in breast epithelial differentiation and mammary gland development.

A 3D in vitro model of the human breast duct: a method to unravel myoepithelial-luminal interactions in the progression of breast cancer

Background3D modelling fulfils a critical role in research, allowing for complex cell behaviour and interactions to be studied in physiomimetic conditions. With tissue banks becoming established for a number of cancers, researchers now have access to primary patient cells, providing the perfect building blocks to recreate and interrogate intricate cellular systems in the laboratory. The ducts of the human breast are composed of an inner layer of luminal cells supported by an outer layer of myoepithelial cells. In early-stage ductal carcinoma in situ, cancerous luminal cells are confined to the ductal space by an intact myoepithelial layer. Understanding the relationship between myoepithelial and luminal cells in the development of cancer is critical for the development of new therapies and prognostic markers. This requires the generation of new models that allows for the manipulation of these two cell types in a physiological setting.MethodsUsing access to the Breast Cancer Now Tissue Bank, we isolated pure populations of myoepithelial and luminal cells from human reduction mammoplasty specimens and placed them into 2D culture. These cells were infected with lentiviral particles encoding either fluorescent proteins, to facilitate cell tracking, or an inducible human epidermal growth factor receptor 2 (HER2) expression construct. Myoepithelial and luminal cells were then recombined in collagen gels, and the resulting cellular structures were analysed by confocal microscopy.Results Myoepithelial and luminal cells isolated from reduction mammoplasty specimens can be grown separately in 2D culture and retain their differentiated state. When recombined in collagen gels, these cells reform into physiologically reflective bilayer structures. Inducible expression of HER2 in the luminal compartment, once the bilayer has formed, leads to robust luminal filling, recapitulating ductal carcinoma in situ, and can be blocked with anti-HER2 therapies.ConclusionsThis model allows for the interaction between myoepithelial and luminal cells to be investigated in an in-vitro environment and paves the way to study early events in breast cancer development with the potential to act as a powerful drug discovery platform.

A Rare Case of Bronchial Epithelial-Myoepithelial Carcinoma with Solid Lobular Growth in a 53-Year-Old Woman.

Epithelial-myoepithelial carcinoma (EMC) of lung is a minor subset of salivary type carcinoma of lung of known low grade malignancy. Histologically, two-cell components forming duct-like structure with inner epithelial cell layer and outer myoepithelial cell layer are characteristics of EMC. In salivary gland, dedifferentiation of conventional low grade malignancy has been reported and is thought to be related with poor prognosis. However, precise histomorphology and prognostic factors of pulmonary EMC have not been clarified due to its rarity. Herein, we reported a rare case of EMC presented as endobronchial mass in a 53-year old woman, which showed predominant solid lobular growth pattern and lymph node metastases.

Columnar cell-like changes in the male breast

AimsColumnar cell lesions are known as a link between normal breast and low grade neoplastic lesions in female, but have not been established in the male breast. This study evaluated...

Encapsulated Minimally Invasive Epimyoepithelial Carcinoma of Submandibular Gland - A New Entity?? With Review of Literature

Encapsulated Minimally Invasive Epimyoepithelial Carcinoma of Submandibular Gland - A New Entity?? With Review of Literature Epimyoepithelial carcinoma (EMC) is a rare low-grade salivary gland malignancy comprising of 1% of all the salivary glands tumors. EMC is a rare tumor when involving submandibular gland (8.6%) as compared to parotid gland (62.1%). A thorough pubmed literature search retrieved only 17 cases of EMC involving submandibular gland since 1972. EMC can present in classical pattern characterised by biphasic cell population with inner layer of cuboidal to columnar cells and outer layer of myoepithelial cells. Encapsulated minimally invasive epimyoepithelial carcinoma is a recently coined terminology by Seethala et al. To the best of our knowledge, this is the first case of encapsulated minimally invasive EMC of submandibular salivary gland discussed in the literature. The present paper highlights the review of literature of EMC involving submandibular salivary gland, histomorphological spectrum and diagnostic differentiation from other salivary gland tumors.

Stem Cell Research: A Novel Boulevard towards Improved Bovine Mastitis Management

The dairy industry is a multi-billion dollar industry catering the nutritional needs of all age groups globally through the supply of milk. Clinical mastitis has a severe impact on udder tissue and is also an animal welfare issue. Moreover, it significantly reduces animal value and milk production. Mammary tissue damage reduces the number and activity of epithelial cells and consequently contributes to decreased milk production. The high incidence, low cure rate of this highly economic and sometimes deadly disease is an alarming for dairy sector as well as policy makers. Bovine mammary epithelial cells (MECs) and their stem cells are very important in milk production and bioengineering. The adult mammary epithelium consists of two main cell types; an inner layer of luminal epithelial cells, which produce the milk during lactation, and an outer layer of myoepithelial cells resting on a basement membrane, which are responsible for pushing the milk through the ductal network to the teat cistern. Inner layer of columner/luminal cells of bovine MECs, is characterized by cytokeratin18, 19 (CK18, CK19) and outer layer such as myoepithelial cells which are characterized by CK14, α-smooth muscle actin (α-SMA) and p63. Much work has been done in mouse and human, on mammary gland stem cell research, particularly in cancer therapy, but stem cell research in bovine is still in its infancy. Such stem/progenitor cell discoveries in human and mouse mammary gland bring some hope for application in bovines. These progenitors may be therapeutically adopted to correct the structural/cytological defects in the bovine udder due to mastitis. In the present review we focused on various kinds of stem/progenitor cells which can have therapeutic utility and their possibilities to use as a potential stem cell therapy in the management of bovine post-mastitis damage in orders to restore milk production. The possibilities of bovine mammary stem cell therapy offers significant potential for regeneration of tissues that can potentially replace/repair diseased and damaged tissue through differentiation into epithelial, myoepithelial and/or cuboidal/columnar cells in the udder with minimal risk of rejection and side effects.

Synchronous bilateral infiltrating syringomatous adenoma of the breast

Infiltrating syringomatous breast adenoma is an uncommon mammary neoplasm composed of angulated glandular structures with a variable amount of epidermoid differentiation which proliferate in a background of dense collagenous stroma. The patient presented with bilateral hardness and oedema of the nipples. Ultrasound and mammography revealed microcalcifications in retromammilary regions of both nipples. Histological examination of the resected specimens showed angulated glands and solid cords, lined by an inner layer of epithelial cells and an outer layer of myoepithelial cells, immersed in desmoplastic stroma. Within the solid cords reminiscent of squamous cells, occasionally aggregated in keratinizing cysts were found. To the best of our knowledge this is the first described case of bilateral infiltrating syringomatous breast adenoma with synchronous presentation. Infiltrating syringomatous adenoma is a rare lesion. A finding of infiltrating syringomatous adenoma in one breast should prompt careful examination of the opposite breast with adequate follow-up.

A Double-Clear Variant of Epithelial-Myoepithelial Carcinoma of the Parotid Gland

The hallmark of the histology of epithelial-myoepithelial carcinoma (EMC) is the presence of a regular repetitive mixture of bilayered duct-like structures with an outer layer of myoepithelial cells and inner ductal epithelial cells. Clear cell change in the myoepithelial component is common, but clearing of both cell types, giving an impression of a monocellular neoplasm, is rare. A parotid biopsy was received from an 83-year-old male and subject to routine histologic processing for conventional staining and immunohistochemistry. The encapsulated tumour was composed of sheets of PAS/diastase negative clear cells, separated by fibrous septae. The clear myoepithelial cells were positive for S-100 protein, SMA, and p63 and negative for CK19 and surrounded CK19-positive luminal cells. It is important to utilise immunohistochemistry to differentiate this tumour from others with a similar histologic pattern. Information about the behaviour of the double-clear EMC is limited since there are few cases reported.

Fine-needle aspiration cytology of eccrine hidrocystoma

Fine-needle aspiration cytology of eccrine hidrocystoma

Apocrine Hidrocystoma of the Cheek

Apocrine Hidrocystoma of the Cheek

The unmasking of novel unipotent stem cells in the mammary gland

The unmasking of novel unipotent stem cells in the mammary gland

Evaluation of Mammary Gland Development and Function in Mouse Models

The human mammary gland is composed of 15-20 lobes that secrete milk into a branching duct system opening at the nipple. Those lobes are themselves composed of a number of terminal duct lobular units made of secretory alveoli and converging ducts1. In mice, a similar architecture is observed at pregnancy in which ducts and alveoli are interspersed within the connective tissue stroma. The mouse mammary gland epithelium is a tree like system of ducts composed of two layers of cells, an inner layer of luminal cells surrounded by an outer layer of myoepithelial cells denoted by the confines of a basement membrane2. At birth, only a rudimental ductal tree is present, composed of a primary duct and 15-20 branches. Branch elongation and amplification start at the beginning of puberty, around 4 weeks old, under the influence of hormones3,4,5. At 10 weeks, most of the stroma is invaded by a complex system of ducts that will undergo cycles of branching and regression in each estrous cycle until pregnancy2. At the onset of pregnancy, a second phase of development begins, with the proliferation and differentiation of the epithelium to form grape-shaped milk secretory structures called alveoli6,7. Following parturition and throughout lactation, milk is produced by luminal secretory cells and stored within the lumen of alveoli. Oxytocin release, stimulated by a neural reflex induced by suckling of pups, induces synchronized contractions of the myoepithelial cells around the alveoli and along the ducts, allowing milk to be transported through the ducts to the nipple where it becomes available to the pups 8. Mammary gland development, differentiation and function are tightly orchestrated and require, not only interactions between the stroma and the epithelium, but also between myoepithelial and luminal cells within the epithelium9,10,11. Thereby, mutations in many genes implicated in these interactions may impair either ductal elongation during puberty or alveoli formation during early pregnancy, differentiation during late pregnancy and secretory activation leading to lactation12,13. In this article, we describe how to dissect mouse mammary glands and assess their development using whole mounts. We also demonstrate how to evaluate myoepithelial contractions and milk ejection using an ex-vivo oxytocin-based functional assay. The effect of a gene mutation on mammary gland development and function can thus be determined in situ by performing these two techniques in mutant and wild-type control mice.

Evaluation of Mammary Gland Development and Function in Mouse Models

The human mammary gland is composed of 15-20 lobes that secrete milk into a branching duct system opening at the nipple. Those lobes are themselves composed of a number of terminal duct lobular units made of secretory alveoli and converging ducts. In mice, a similar architecture is observed at pregnancy in which ducts and alveoli are interspersed within the connective tissue stroma. The mouse mammary gland epithelium is a tree like system of ducts composed of two layers of cells, an inner layer of luminal cells surrounded by an outer layer of myoepithelial cells denoted by the confines of a basement membrane. At birth, only a rudimental ductal tree is present, composed of a primary duct and 15-20 branches. Branch elongation and amplification start at the beginning of puberty, around 4 weeks old, under the influence of hormones. At 10 weeks, most of the stroma is invaded by a complex system of ducts that will undergo cycles of branching and regression in each estrous cycle until pregnancy. At the onset of pregnancy, a second phase of development begins, with the proliferation and differentiation of the epithelium to form grape-shaped milk secretory structures called alveoli. Following parturition and throughout lactation, milk is produced by luminal secretory cells and stored within the lumen of alveoli. Oxytocin release, stimulated by a neural reflex induced by suckling of pups, induces synchronized contractions of the myoepithelial cells around the alveoli and along the ducts, allowing milk to be transported through the ducts to the nipple where it becomes available to the pups. Mammary gland development, differentiation and function are tightly orchestrated and require, not only interactions between the stroma and the epithelium, but also between myoepithelial and luminal cells within the epithelium. Thereby, mutations in many genes implicated in these interactions may impair either ductal elongation during puberty or alveoli formation during early pregnancy, differentiation during late pregnancy and secretory activation leading to lactation. In this article, we describe how to dissect mouse mammary glands and assess their development using whole mounts. We also demonstrate how to evaluate myoepithelial contractions and milk ejection using an ex-vivo oxytocin-based functional assay. The effect of a gene mutation on mammary gland development and function can thus be determined in situ by performing these two techniques in mutant and wild-type control mice.

The CD10 Enzyme Is a Key Player to Identify and Regulate Human Mammary Stem Cells

The major components of the mammary ductal tree are an inner layer of luminal cells, an outer layer of myoepithelial cells, and a basement membrane that separates the ducts from the underlying stroma. Cells in the outer layer express CD10, a zinc-dependent metalloprotease that regulates the growth of the ductal tree during mammary gland development. To define the steps in the human mammary lineage at which CD10 acts, we have developed an in vitro assay for human mammary lineage progression. We show that sorting for CD10 and EpCAM cleanly separates progenitors from differentiated luminal cells and that the CD10-high EpCAM-low population is enriched for early common progenitor and mammosphere-forming cells. We also show that sorting for CD10 enriches sphere-forming cells from other tissue types, suggesting that it may provide a simple tool to identify stem or progenitor populations in tissues for which lineage studies are not currently possible. We demonstrate that the protease activity of CD10 and the adhesion function of beta1-integrin are required to prevent differentiation of mammary progenitors. Taken together, our data suggest that integrin-mediated contact with the basement membrane and cleavage of signaling factors by CD10 are key elements in the niche that maintains the progenitor and stem cell pools in the mammary lineage.

Intraductal papilloma of ectopic breast tissue in axillary lymph node of a patient with a previous intraductal papilloma of ipsilateral breast: a case report and review of the literature

The presence of ectopic breast tissue in axillary lymph nodes (ALN) is a benign condition that must be differentiated from primary or metastatic carcinoma. Here we report a patient who underwent excision of enlarged ALN 10 years after she had received surgical treatment of ipsilateral breast for an intracystic intraductal papilloma (IDP). Histological examination of the removed ALN revealed that the proliferative lesion consisted of papillary and tubular structures lined by luminal cuboidal cells and a distinct outer layer of myoepithelial cells resembling IDP of the breast. Immunostaining with a set of immunohistochemical markers including AE/AE3, alpha-smooth muscle actin and p63 in combination with estrogen and progesterone receptors confirmed the diagnosis of ectopic IDP.This case shows that even though benign proliferative change in ectopic breast tissue is an extremely rare phenomenon, this possibility should be taken into account for correct diagnosis.

Unusual epithelial-myoepithelial carcinoma in palate - case report and immunohistochemical study

Ephitelial-myoepithelial carcinoma (EMC) is a neoplasm of salivary gland extremely rare and low-grade malignant, exhibiting predilection for major salivary gland, especially parotid gland. This paper described a case of EMC localized in soft palate. The initial clinical diagnosis were mucoepidermoid and adenoid cystic carcinoma. A incisional biopsy was performed, and the histological diagnosis was adenocarcinoma not otherwise specified. The patient underwent excisional biopsy, where was realized immunohistochemical analysis, staining the duct-like structures, where the inner layer of epithelial cells positively for CK 14, whereas outer layer of myoepithelial cells stained positively for smooth muscle actin (SMA) and vimentin antibodies. Based on these findings, the final histological diagnosis was EMC. The patient was submitted 30 sessions of radiotherapy, and she is being follow-up about 2 years without evidence recurrences.

Nerve Invasion by Epithelial Cells in Benign Breast Diseases

Nerve invasion by glandular epithelial cells in a lesion is usually regarded as invasive carcinoma. However, some benign conditions in the pancreas, prostate, breast and other organs may show involvement of nerve bundles by benign epithelial cells. We report an 18-year-old female with nerve invasion in benign breast disease. The lesion in her right breast revealed fibrocystic changes with ductal hyperplasia and stromal sclerosis. Perineural and intraneural involvement by bland-looking small ducts lined by 2 layers of cells including an outer layer of myoepithelial cells were found, suggestive of benign nerve invasion. There was no evidence of malignant cells in any of the sections. The patient remains well after 31 months of follow-up. About 44 cases of nerve invasion in benign breast diseases have been reported in the literature. It is necessary to carefully evaluate nerve involvement in breast lesions to avoid over-diagnosis and inappropriate operation.

Clinical, histological and immunohistochemical features of ceruminous adenoma

Ceruminous gland tumors are infrequent lesions of the external auditory canal (EAC). Controversy exists regarding several aspects of these tumors. In this report we presented a case of 63 years old woman with an 8-year history of a painless mass in the left EAC. Physical examination showed a skin-covered mass, occupying all its lumen. First superficial biopsy led to an initial erroneous diagnosis of papilloma. Local wide resection of the lesion was performed one month later. Histological examination revealed a lesion composed of solid nests and papillomatous and cystic glands surrounded by a hyaline sheath. Immunohistochemically, two different cell layers were demonstrated: a luminal epithelial cell layer with positive staining with cytokeratin 7 (CK7) and an outer myoepithelial cell layer, with positive staining with actin and S-100 protein. The proliferative index (Ki-67) was very low. The diagnosis was ceruminous gland adenoma. Two years after the operation, the patient is in good health and with normal ultrasound and laboratory results. We believe that conservative surgery seems to be ideal treatment in case of ceruminous adenoma.

Myoepithelial cell cocktail (p63+SMA) for the evaluation of sclerosing breast lesions

Sclerosing breast lesions may sometimes mimic the appearance of infiltrating carcinoma due to the entrapment of ductular structures in a fibrotic core. The immunohistochemical detection of the outer myoepithelial cell layer that is indicative of a non-infiltrating lesion is a valuable clue for the diagnosis of such ambiguous cases. The myoepithelial cell markers smooth muscle actin (SMA) and p63 are most commonly used since their specificity and sensitivity are well established. However, recent studies have indicated that some morphologically distinct myoepithelial cells fail to stain for SMA and that p63 positivity can be rarely expressed by a subset of malignant epithelial cells. Moreover, SMA can also be positive in stromal myofibroblastic cells and normal vessels that can be found close to the entrapped ductules and might be erroneously interpreted as myoepithelial cells. In this study, we used a double-immunolabeling technique combining both SMA and p63 antibodies (myoepithelial cell cocktail), in order to investigate whether this technique is advantageous over either marker used alone, in diagnosing sclerosing breast lesions. Our results indicate that p63 alone is not a useful myoepithelial cell marker if applied in large sclerosing breast lesions, however, in smaller lesions it is still of high value. On the contrary, SMA proved significantly useful in the evaluation of myoepithelial cells in larger but not in smaller complex sclerosing lesions. The myoepithelial cell cocktail has a staining sensitivity identical to that of SMA. Nevertheless, in a certain number of cases the cocktail might be useful in differentiating myoepithelial cells from stromal myofibroblasts or vascular smooth muscle cells due to the false impression of a higher staining intensity of the cocktail resulting from the expression of both nuclear and cytoplasmic/membranous antibodies that occupy a wider area of the cell under control.

Myoepithelial cells: their origin and function in breast morphogenesis and neoplasia.

The human breast epithelium is a branching ductal system composed of an inner layer of polarized luminal epithelial cells and an outer layer of myoepithelial cells that terminate in distally located terminal duct lobular units (TDLUs). While the luminal epithelial cell has received the most attention as the functionally active milk-producing cell and as the most likely target cell for carcinogenesis, attention on myoepithelial cells has begun to evolve with the recognition that these cells play an active part in branching morphogenesis and tumor suppression. A major question that has been the subject of investigation pertains to how the luminal epithelial and myoepithelial lineages are related and precisely how they arise from a common putative stem cell population within the breast. Equally important is the question of how heterotypic signaling occurs between luminal epithelial and surrounding myoepithelial cells in normal breast morphogenesis and neoplasia. In this review we discuss data from our laboratories and from others regarding the cellular origin of human myoepithelial cells, their function in maintaining tissue polarity in the normal breast, and their role during neoplasia.