Acinar Epithelium Research Articles

Accumulation of Secretory Vesicles in the Lacrimal Gland Epithelia Is Related to Non-Sjögren's Type Dry Eye in Visual Display Terminal Users

Previous observations in a rat model of a non-Sjögren's syndrome (non-SS) type of dry eye seen in users of visual display terminals (VDT) indicated that secretory vesicle (SV) accumulation in the lacrimal gland epithelia contributes to the condition. Here, to examine this possibility in humans, we compared the lacrimal gland histology and percent SV area in the cytoplasm of acinar epithelial cells using light microscopy and transmission electron microscopy, in patients with VDT work-related non-SS dry-eye (VDT group), SS-induced dry-eye, and autopsied normal controls. In addition, the VAMP8 (vesicle-associated membrane protein 8, an exocrine-pathway molecule) and Rab3D (mature vesicle marker) were histochemically examined in lacrimal gland tissue sections. The lacrimal gland acini were larger in the VDT group than in the SS group, and the percent SV area was significantly higher in the VDT group than in the normal controls (P = 0.021) or SS group (P = 0.004). Immunostaining revealed abnormal distributions of VAMP8 in the VDT and SS groups. Rab3D was more strongly expressed in the cytoplasm of acinar epithelial cells in the VDT group than in that of normal controls. The duration of VDT use was significantly longer in the VDT group than in the other groups. These findings suggest that excessive SV accumulation in the acinar epithelia may contribute to the reduced tear secretion in VDT users.

Cyclic AMP regulates formation of mammary epithelial acini in vitro

Epithelial cells form tubular and acinar structures notable for a hollow lumen. In three-dimensional culture utilizing MCF10A mammary epithelial cells, acini form due to integrin-dependent polarization and survival of cells contacting extracellular matrix (ECM), and the apoptosis of inner cells of acini lacking contact with the ECM. In this paper, we report that cyclic AMP (cAMP)-dependent protein kinase A (PKA) promotes acinus formation via two mechanisms. First, cAMP accelerates redistribution of α6-integrin to the periphery of the acinus and thus facilitates the polarization of outer acinar cells. Blocking of α6-integrin function by inhibitory antibody prevents cAMP-dependent polarization. Second, cAMP promotes the death of inner cells occupying the lumen. In the absence of cAMP, apoptosis is delayed, resulting in perturbed luminal clearance. cAMP-dependent apoptosis is accompanied by a posttranscriptional PKA-dependent increase in the proapoptotic protein Bcl-2 interacting mediator of cell death. These data demonstrate that cAMP regulates lumen formation in mammary epithelial cells in vitro, both through acceleration of polarization of outer cells and apoptosis of inner cells of the acinus.

Histological study of experimental hyperprolactinemia on the prostate lateral lobe of adult albino rats

Introduction Prolactin, besides androgens, plays an important role in the regulation of prostatic function. Aim of the study This study aimed to demonstrate the influence of experimental hyperprolactinemia on the structure of the prostate lateral lobe in adult albino rats. Materials and methods Twenty healthy adult albino rats were equally divided into two groups: a control group and an experimental group. Rats of the experimental group were intraperitoneally injected with metoclopramide at a dose of 2.2mg/kg for 14 successive days to induce hyperprolactinemia. The control group was injected with saline in the same manner. Hormonal assays for serum prolactin and testosterone levels were carried out. Prostate was extirpated and the lateral lobes were processed for examination by light and electron microscopy. Epithelial height of the prostatic lateral lobes acini was determined morphometrically and analyzed statistically. Results In the experimental hyperprolactinemic group, numerous prostatic acini were lined by multiple layers of epithelial cells (hyperplasia). Acinar epithelium had different ultrastructural features. Some acini had pleomorphic nuclei, cytoplasmic vacuoles, and residual bodies. Others were packed with extensive cisternae of rough endoplasmic reticulum and secretory vesicles. Others had few secretory vesicles and the majority of them had centrally located flocculent material surrounded by electron-lucent zones. Some epithelial cells contained lipofuscin pigments. The prostatic epithelial lining was infiltrated by inflammatory cells. Stromal thickening was found in between some acini that was surrounded by prominent smooth muscle cells and many connective tissue cells. Hormonal assays showed increased serum prolactin and decreased testosterone as compared with the control group. The estimated and analyzed epithelial height of the prostatic acini showed a highly significant increase compared with the control group. Conclusion Hyperprolactinemia altered the morphology of epithelium and stroma of the prostate lateral lobe. It played a significant role in inducing a prostatic hyperplasia and an inflammatory response that triggered the abnormal growth of prostate.

Mucosal Immune Function Comparison Between Amenorrheic and Eumenorrheic Distance Runners

This study examined the effects of amenorrhea on mucosal immune function and susceptibility to upper respiratory tract infection (URTI) in elite female distance runners. Based on their menstrual cycles during the prior year, 21 elite, collegiate, female distance runners were designated as eumenorrheic runners (ERs; n = 8; 19.9 ± 0.8 years) or amenorrheic runners (ARs; n n = 13; 20.0 ± 0.3 years). Resting saliva and blood samples were collected in the morning. The secretory immunoglobulin A (SIgA) concentration was measured using enzyme-linked immunosorbent assay. The SIgA secretion rate was calculated. Serum 17β-estradiol concentrations and serum progesterone concentrations were measured using radioimmunoassay. Subjects reported the appearance of URTI symptoms (sore throat, headache, runny nose, coughing, or fever), if any, during the prior month. The serum estradiol concentration and salivary SIgA secretion rate were significantly lower for ARs than for ERs (p < 0.05). Serum progesterone concentration was not significantly different between groups. Higher frequencies of headache, runny nose, coughing, and fever were observed in ARs than in ERs. Results show that athletic amenorrhea with low estrogen might accelerate downregulation of mucosal immune function in athletes and enhance susceptibility to infection.

P38 Mitogen-activated Protein Kinase and Nuclear Factor-κB Facilitate CD40-mediated Salivary Epithelial Cell Death

Our previous studies indicated that CD40-mediated Fas-dependent apoptosis is important for the glandular destruction of Sjögren's syndrome (SS), although other immune and nonimmune mechanisms are also involved in exocrine dysfunction. We investigated the roles of p38 mitogen-activated protein kinase (p38MAPK) and nuclear factor-κB (NF-κB) in salivary epithelial cell death in SS. Expression of p38, phosphorylated p38 (pp38), and IκB-α was examined by Western blotting upon CD40 ligation. Activity of NF-κB induced by anti-CD40 monoclonal antibody (mAb) was examined by electrophoretic mobility shift assay (EMSA) and Western blotting. Expression of Fas was analyzed by flow cytometry and Western blotting with or without the p38-specific inhibitor SB203580 or the NF-κB-specific inhibitor caffeic acid phenethyl ester (CAPE). Induction of apoptosis in salivary epithelial cells was examined by DNA fragmentation and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay. Expression of phosphorylated p38MAPK and NF-κB was measured by immunohistochemistry. pp38MAPK and NF-κB p65 were predominantly expressed in the ductal and acinar epithelium adjacent to lymphoid infiltrates of SS salivary gland by immunohistochemistry. CD40 ligation strongly enhanced p38MAPK and NF-κB activity by EMSA and Western blotting in cultured salivary epithelial cells. Treatment of cells with anti-CD40 mAb resulted in significantly upregulated Fas expression and induction of Fas-dependent apoptosis. Inhibition of p38MAPK and NF-κB activity by SB203580 and/or CAPE reduced Fas expression and apoptosis in salivary epithelial cells, establishing p38MAPK and NF-κB as proapoptotic factors in this context. CD40 ligation plays an important role in activation of p38MAPK, NF-κB, and Fas molecules to initiate proapoptotic signaling. p38MAPK and NF-κB collaborate in regulation of proapoptotic signaling in CD40-mediated Fas-dependent apoptosis in salivary epithelial cells.

Evidence for Changes in RREB-1, ZIP3, and Zinc in the Early Development of Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma is an untreatable cancer with a 5-year survival rate of about 6 % or less for the past 35years. This lack of significant progress is largely due to the lack of elucidation and understanding of the factors involved in the development of this cancer. Recent studies identified and implicated zinc in the development and progression of pancreatic cancer. This study was conducted to establish the changes in zinc, ZIP3 zinc transporter, and Ras-responsive element-binding protein 1 (RREB-1) transcription factor as early events in the development of malignancy. In situ relative zinc determination and immunohistochemical analysis of ZIP3 and RREB-1 were performed on archived human pancreatic tissue sections and tissue microarrays. Normal/benign versus adenocarcinoma pancreas was compared. Panc1 cells were employed to determine the influence of RREB-1 on ZIP3 expression. Zinc levels of normal ductal and acinar epithelium were markedly and consistently decreased in adenocarcinoma. Pancreatic intraepithelial neoplasia (PanIN) lesions also exhibited a loss of zinc. ZIP3 and RREB-1 were also markedly downregulated. Initial results indicate that RREB-1 regulates ZIP3 expression. These results corroborate the earlier report that zinc, ZIP3, and RREB-1 are markedly decreased in early stage adenocarcinoma. Additionally and most importantly, these changes occur in PanIN, which are thought to be precancerous lesions leading to ductal adenocarcinoma. These results support a concept that downregulation of RREB-1 causes downregulation of ZIP3, which results in decreased zinc in premalignant and carcinoma cells. The decrease in zinc is essential to remove its cytotoxic effects on malignant cells. This relationship constitutes a new concept of early genetic/metabolic events in the progressive transformation of normal cells to premalignant cells to malignant cells in the development of pancreatic cancer.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Novel Image Analysis Approach Quantifies Morphological Characteristics of 3D Breast Culture Acini with Varying Metastatic Potentials

Prognosis of breast cancer is primarily predicted by the histological grading of the tumor, where pathologists manually evaluate microscopic characteristics of the tissue. This labor intensive process suffers from intra- and inter-observer variations; thus, computer-aided systems that accomplish this assessment automatically are in high demand. We address this by developing an image analysis framework for the automated grading of breast cancer in in vitro three-dimensional breast epithelial acini through the characterization of acinar structure morphology. A set of statistically significant features for the characterization of acini morphology are exploited for the automated grading of six (MCF10 series) cell line cultures mimicking three grades of breast cancer along the metastatic cascade. In addition to capturing both expected and visually differentiable changes, we quantify subtle differences that pose a challenge to assess through microscopic inspection. Our method achieves 89.0% accuracy in grading the acinar structures as nonmalignant, noninvasive carcinoma, and invasive carcinoma grades. We further demonstrate that the proposed methodology can be successfully applied for the grading of in vivo tissue samples albeit with additional constraints. These results indicate that the proposed features can be used to describe the relationship between the acini morphology and cellular function along the metastatic cascade.

TRIM29 Functions as a Tumor Suppressor in Nontumorigenic Breast Cells and Invasive ER+ Breast Cancer

Tripartite motif-containing 29 (TRIM29) is a member of the TRIM protein family that has been implicated in hematologic and solid tumor cancers. We found that TRIM29 functions as a tumor suppressor in both the nontumorigenic MCF10A [estrogen receptor (ER)-/TRIM29+] breast cell line and the invasive MCF7 (ER+/TRIM29-) breast cell line. Silencing TRIM29 in MCF10A cells resulted in preneoplastic changes that included loss of polarity in three-dimensional culture, increased proliferation, anchorage-independent growth, and increased migration and invasion. Conversely, the introduction of TRIM29 into MCF7 cells caused reversion to a less aggressive phenotype by antagonizing the growth effect of 17β-estradiol. The interaction between TRIM29 and ER signaling in MCF7 cells was supported by a reduction in ERE binding in the presence of TRIM29 and suppression of ER-dependent gene expression of TFF1, FOS, and GREB1. By microarray analyses, we showed that younger women (<55 years of age) with early-stage, ER+ breast cancer who were given no adjuvant systemic therapy had a significantly lower risk of relapse when their tumor had high TRIM29 expression (P = 0.02). This effect was not observed in older women (>55 years of age) and thus may be due to menopause and loss of circulating estrogens. Our results suggest that loss of TRIM29 expression in normal breast luminal cells can contribute to malignant transformation and lead to progression of ER+ breast cancer in premenopausal women.

Unilateral gynecomastia in a prepubertal boy

We report the case of a 12-year-old Caucasian boy with an enlarged left breast without significant skin excess. According to Simon [1] this is a grade I (Fig. 1). The boy, suffering from ADHD, had been treated since the age of 4 years with methylphenidate (10 mg/day), a potent central nervous system stimulant and amphetamine derivative. At the age of 6 years, unilateral gynecomastia was diagnosed, with an ongoing progression causing an emotional burden. On physical examination, the left breast was enlarged without galactorrhea, nipple discharge, nipple retraction, lymphadenopathy, or skin changes. Palpation of the right breast did not show any conspicuous findings. Preoperative ultrasound showed diffuse nodular breast gland hypertrophy (7×5×1 cm) of low echogenity and dense stromal fibrosis with no evidence of microcalcification, or cyst formation. The boy underwent subcutaneous mastectomy through a semicircular inferior periareolar incision. (Fig. 2) Histological examination revealed a ductal and acinar breast epithelium with stroma, fibrosis, and glandular hyperplasia with no evidence of malignancy confirming the diagnosis as “true gynecomastia.” The patient had an uneventful postoperative recovery. A 6-month follow-up showed no recurrence, and the right breast was still inconspicuous. Further systematic studies are needed to analyze endocrine dysfunctions associated with methylphenidate treatment in young patients with ADHD.

PERK Integrates Autophagy and Oxidative Stress Responses To Promote Survival during Extracellular Matrix Detachment

Mammary epithelial cells (MECs) detached from the extracellular matrix (ECM) produce deleterious reactive oxygen species (ROS) and induce autophagy to survive. The coordination of such opposing responses likely dictates whether epithelial cells survive ECM detachment or undergo anoikis. Here, we demonstrate that the endoplasmic reticulum kinase PERK facilitates survival of ECM-detached cells by concomitantly promoting autophagy, ATP production, and an antioxidant response. Loss-of-function studies show that ECM detachment activates a canonical PERK-eukaryotic translation initiation factor 2α (eIF2α)-ATF4-CHOP pathway that coordinately induces the autophagy regulators ATG6 and ATG8, sustains ATP levels, and reduces ROS levels to delay anoikis. Inducible activation of an Fv2E-ΔNPERK chimera by persistent activation of autophagy and reduction of ROS results in lumen-filled mammary epithelial acini. Finally, luminal P-PERK and LC3 levels are reduced in PERK-deficient mammary glands, whereas they are increased in human breast ductal carcinoma in situ (DCIS) versus normal breast tissues. We propose that the normal proautophagic and antioxidant PERK functions may be hijacked to promote the survival of ECM-detached tumor cells in DCIS lesions.

Decreased zinc and downregulation of ZIP3 zinc uptake transporter in the development of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is an untreatable deadly cancer. The factors involved in its early development remain unknown; which contributes to the absence of biomarkers for early detection of malignancy or at-risk subjects, and the absence of efficacious therapeutic agents. Because zinc changes are implicated in some cancers, we determined if it might be involved in the development of pancreatic adenocarcinoma. With in situ Dithizone and Zinquin staining of normal pancreas and adenocarcinoma tissue sections, we show for the first time, a consistent major loss of zinc in ductal and acinar epithelium in adenocarcinoma compared to the normal epithelium. This decrease in zinc is evident in well-differentiated through poorly-differentiated stages of malignancy. Immunohistochemistry identified ZIP3 as the basilar membrane zinc uptake transporter in normal ductal/acinar epithelium; and that the transporter is absent in adenocarcinoma. In situ Rt-PCR revealed that ZIP3 gene expression is silenced in adenocarcinoma. The ZIP3 down regulation accompanied the loss of zinc in early and progressing malignancy. RREB1 transcription factor was down regulated along with ZIP3; and might be involved in the silencing of ZIP3 expression. Zinc treatment was cytotoxic to malignant Panc1 cells. The combination of concurrent zinc, ZIP3, and RREB-1 changes represent early events in the development of adenocarcinoma; and suggest that zinc might be a tumor suppressor of pancreatic cancer. This report provides the clinical foundation for further mechanistic studies that will provide important insight into pancreatic carcinogenesis, and can lead to the development of effective early biomarkers and effective therapeutic agents for pancreatic cancer.

Destruction of Salivary and Lacrimal Glands by Th1-Polarized Reaction in a Model of Secondary Sjögren’s Syndrome in Lupus-Prone Female NZB × NZWF1 Mice

T helper (Th)1/Th2 balance determines the direction of some kinds of autoimmune diseases. The involvement of acini areas by CD4(+) helper T(Th) cell subset in submandibular and lacrimal glands are largely unknown in secondary Sjögren's syndrome (sSjS) with systemic lupus erythematosus (SLE). Submandibular and lacrimal glands were examined immunopathologically in lupus-prone female NZB × NZW(B/W)F(1) mice, model for human sSjS with SLE. Dacryoadenitis and sialoadenitis with renal failure developed with age. Infiltration of lymphoid cells (lymphocytes and plasma cells) expanded from the periductal areas in striated ducts to the acini, and the isolated foci in the acini were observed in those organs. The destruction of duct and acini epithelium, including the myoepithelium, was induced by interferon (IFN)-γ(+) and IgG2a(+) lymphoid cells, but not by interleukin(IL)-4(+), IL-5(+), IL-13(+), and IgG1(+) lymphoid cells. Compared with IL-5 and IL-13, high values of IFN-γ were produced systemically at various ages. Also local expression of IFN-γ mRNA was higher than that of IL-4 mRNA. The result suggests that the acini destruction in submandibular and lacrimal glands may be induced by systemic and local Th1 cell dominant reactions in lupus-prone B/WF(1) mice with sSjS.

Aquaporins at a glance

With a concentration of 55,000 mM, water is by far the most prevalent molecule in biological systems. For many years it was assumed that biological membranes are freely water permeable, so that the existence of a family of water channels would not have been predicted. However, biophysical studies in

RANKL inhibition: a promising novel strategy for breast cancer treatment

The cytokine RANKL and its receptor RANK, key proteins in bone remodelling and bone metastasis, are essential for mammary gland development in mice. RANK absence or overexpression results in a lactation defect and a non-functional mammary gland. RANKL signalling mediates progesterone-induced proliferation and expansion of the stem cell compartment in the mouse mammary gland. RANK overexpressing mammary epithelial acini show hallmarks of transformation in a RANKL-dependent manner. Complementary gain- and loss-of-function approaches (RANK transgenic and knock-out mouse models and pharmacological RANKL inhibition) define a direct contribution of this pathway to progestin-driven mammary cancer. Moreover, decreased RANKL signalling attenuates preneoplasic lesions and lung metastasis in the spontaneous model of mammary tumorigenesis MMTV-neu, suggesting that RANK pathway promotes mammary tumorigenesis and metastasis in a wider tumour spectrum and beyond its established role in bone metastasis. In this review, we summarise the role of the RANKL pathway in mammary gland development, breast cancer and metastasis, and discuss the potential application of RANKL inhibition for breast cancer treatment.

273 ANDROGEN INDEPENDENT, TUMOR-REINITIATING CELLS ARE SELECTED BY ANDROGEN DEPRIVATION IN MODELS OF ANDROGEN DEPENDENT PROSTATE CANCER

INTRODUCTION AND OBJECTIVES: Androgen deprivation (AD) therapy remains the standard treatment for non-organ confined prostate cancer (PCa). We previously demonstrated (GuzmanRamirez N et al 2009) radical prostatectomy samples and PCa xenograft models and cell lines contain stem/progenitor (S/P) and neuroendocrine (NE)cells. Although the normal prostate depends on androgens for its growth and secretory function, its acinar epithelium cells reinitiate growth when androgens are given indicating the presence of S/P and NE cells surviving AD. Here we investigated whether AD selects for S/Pand NE-like cells in androgen-dependent PCa models in vivo and in vitro. METHODS: The BM18 human xenograft model, which shows a nearly complete regression and no spontaneous relapse after AD, and the androgen dependent cell line LNCaP were used. AD was achieved in vivo by castration of tumor bearing mice and in vitro by bicalutamide treatment. Hormone replacement (HR) after AD was accomplished in vivo by administration of testosterone-pellets to tumor bearing mice and in vitro by androgen replenished medium. Gene expression was measured by realtime PCR and Immunostaining. Apoptosis and Proliferation was assessed by cell cycle analysis and Ki67 Immunostaining. RESULTS: BM18 tumors regress in average 96.5% in volume (SD: 2.1%) within 14 days of AD. Residual cells are positive for the luminal cytokeratin (CK) 18, but, compared to intact tumors, show a loss of luminal markers such as AR, Nkx3.1 and PSA. Further, expression of markers of S/P (Oct4, Sox2, Nanog, Bcl2, Bmi1, ƒN2-integrin, CD44) and NE (CgA, NSE, Synaptophysin) is strongly increased. In accordance, in LNCaP cells AD selects for CK18 positive cells with decreased Nkx3.1 and PSA expression and with increased NSE expression. After AD residual BM18 tumor cells are quiescent, while residual LNCaP cells maintain a subset of proliferative cells. In both models, HR reactivates proliferation and Nkx3.1 and PSA expression while reducing NSE expression. CONCLUSIONS: Our results suggest that AD therapy selects for S/Pand NE-like PCa cells in vitro and in vivo, which are able to reinitiate a tumor. Restoration of androgenic signaling in these cells induces the outgrowth of a more differentiated cellular phenotype. As AD resistant cells can even be proliferative without androgens, AD therapy may select for the outgrowth of a more malignant cellular phenotype leading to castration resistance.

Clinical and Morphologic Changes in Ewes and Fetuses Poisoned by Ipomoea Carnea Subspecies Fistulosa

Intoxication with Ipomoea carnea has been reported in goats, sheep, and cattle in tropical regions worldwide. The disease has been characterized only in goats; therefore, the present study was conducted in sheep. Nine animals were fed feed rations that contained 3 different concentrations of Ipomoea carnea subsp. fistulosa. Individual intake varied between 10.5 and 135.2 g of fresh plant per kilogram of body weight (BW) per day. Animals first showed clinical signs between day 43 and day 63. The maximum survival time was 133 days. Sheep presented with weight loss and neurologic abnormalities. Neurologic signs were dominated by marked depression, abnormal behavior, and musculoskeletal weakness, with poorly defined motor and proprioceptive deficits. In mature animals, cytoplasmic vacuolation, consistent with accumulation of secondary lysosomes, affected neurons, astrocytes, exocrine pancreatic acinar epithelia, hepatocytes and Kupffer cells, renal tubular epithelia, thyroid follicular epithelia, cortical adrenal epithelia, endothelia and perivascular cells, and macrophages in lymph nodes and spleen. In the central nervous system, there was axonal degeneration and astrogliosis. Abortion was observed as early as day 22 of the trial. In fetal tissues and placenta of chronically poisoned ewes, cytoplasmic vacuolation was histologically detected in neurons, exocrine pancreatic acinar epithelia, hepatocytes, renal tubular epithelia, and thyroid follicular epithelia. All the sheep developed a glycoprotein storage disease, with lysosomal accumulation of N-glycosidically linked oligosaccharides, which was indistinguishable from that induced by the alkaloid swainsonine alone.

Distribution of Dendritic Cells in Normal Human Salivary Glands

Dendritic cells (DC) are believed to contribute to development of autoimmune sialadenitis, but little is known about their distribution in normal salivary glands. In this study, DC were identified and their distribution was determined in normal human parotid and submandibular glands. For light microscopy, salivary gland sections were stained with H&E or immunocytochemically using antibodies to DC markers. Transmission electron microscopy (TEM) was used to evaluate the ultrastructural characteristics of DC. In H&E sections, elongated, irregularly shaped nuclei were occasionally seen in the striated and excretory duct epithelium. Immunolabeling with anti-HLA-DR, anti-CD11c and anti-S100 revealed DC with numerous processes extending between ductal epithelial cells, often close to the lumen. Morphometric analyses indicated that HLA-DR-positive DC occupied approximately 4–11% of the duct wall volume. Similar reactive cells were present in acini, intercalated ducts and interstitial tissues. TEM observations revealed cells with indented nuclei containing dense chromatin, pale cytoplasm with few organelles, and lacking junctional attachments to adjacent cells. These results indicate that DC are abundant constituents of normal human salivary glands. Their location within ductal and acinar epithelium suggests a role in responding to foreign antigens and/or maintaining immunological tolerance to salivary proteins.

Necrotizing Sialometaplasia of the Parotid Gland in a Dog

Necrotizing sialometaplasia (NS) is a self-limiting, benign, ischemic, inflammatory disease that is most often described in the submandibular glands of dogs, with clinical and histologic features that resemble malignancy. Unilateral swelling of the parotid salivary gland in a 7-year-old Cocker Spaniel dog was diagnosed as NS. The dog also had otitis externa on the same side as the parotid gland lesions. The main histologic features were included lobular necrosis of salivary tissue; fibrinoid necrosis of some arteries; marked squamous metaplasia of duct and/or acinar epithelium, with intercellular bridge formation; preservation of salivary lobular morphology; and variable inflammation and fibrosis. Etiologic factors for NS in both humans and animals remain obscure.

Hypoxia Suppression of Bim and Bmf Blocks Anoikis and Luminal Clearing during Mammary Morphogenesis

Proper adhesion to extracellular matrix is critical for epithelial cell survival. Detachment from matrix signals results in apoptosis, referred to as anoikis. Selective apoptosis of cells that become detached from matrix is associated with the formation of a lumen in three-dimensional mammary epithelial acinar structures in vitro. Because early breast cancer lesions such as carcinoma in situ, characterized by ducts exhibiting lumens filled with cells, are often associated with hypoxic markers, we sought to examine the role of hypoxia in anoikis and lumen formation in mammary epithelial cells. Here, we show that hypoxic conditions inhibit anoikis and block expression of proapoptotic BH3-only family members Bim and Bmf in epithelial cells. Hypoxia-mediated anoikis protection is associated with increased activation of the epidermal growth factor receptor-mitogen-activated protein kinase kinase-extracellular signal-regulated kinase (Erk) kinase pathway and requires the hypoxia-activated transcription factor. Consistent with these data, hypoxic conditions inhibit luminal clearing during morphogenesis in human mammary epithelial acini when grown in three-dimensional cultures and are associated with decreased expression of Bim and Bmf as well as Erk activation. We show that hypoxia regulates specific cell survival pathways that disrupt tissue architecture related to clearing of luminal space during mammary morphogenesis and suggest that hypoxia-mediated anoikis resistance may contribute to cancer progression.