Sandra J. Olson

Distribution of reducible 4-hydroxynonenal adduct immunoreactivity in Alzheimer disease is associated with APOE genotype

Two major risk factors for late-onset familial and sporadic Alzheimer disease (AD), a leading cause of dementia worldwide, are increasing age and inheritance of the ϵ4 allele of the apolipoprotein E gene (APOE4). Several isoform-specific effects of apoE have been proposed; however, the mechanisms by which apoE isofoems influence the pathogenesis of AD are unknown. Also associated with AD is increased lipid peroxidation in the regions of the brain most damaged by disease. 4-hydroxynonenal (HNE), the most potent neurotoxic product of lipid peroxidation, is thought to be deleterious to cells through reactions with protein nucleophiles. We tested the hypothesis that accumulation of the most common forms of HNE-protein adducts, borohydride-reducible adducts, is associated with AD and examined whether there was a relationship to APOE. Our results demonstrated that reducible HNE adducts were increased in the hippocampus, entorhinal cortex, and temporal cortex of patients with AD. Furthermore, our data showed that the pattern of reducible HNE adduct accumulation was related to APOE genotype; AD patients homozygous for APOE4 had pyramidal neuron cytoplasmic accumulation of reducible HNE adducts, while AD APOE3 homozygotes had both pyramidal neuron and astrocyte accumulation of reducible HNE adducts. This is in contrast to our previous observations that a distinct HNE protein adduct, the pyrrole adduct, accumulates on neurofibrillary tangles in AD patients. We conclude that APOE genotype influences the cellular distribution of increased reducible HNE adduct accumulation in AD.

Dominant-negative notch3 receptor inhibits mitogen-activated protein kinase pathway and the growth of human lung cancers

Notch3 is a member of an evolutionarily conserved family of cell surface receptors important in cell-fate determination in both vertebrates and invertebrates. Significant data support the role of Notch pathway in cancer development, although the conflicting role of Notch signaling pathways in tumorigenesis suggests that its action is highly context-dependent. Furthermore, although Notch receptors signal primarily through the regulation of hairy enhancer of split (HES) and HES-related (HRT) genes, they are known to crosstalk with other signaling pathways, including the epidermal growth factor (EGF) and the mitogen-activated protein kinase pathways. Whereas much is known about the role of Notch1 in human cancer, the role of Notch3 in epithelial tumors, such as lung carcinomas, has not been well established. In this study, we show that Notch3 is expressed in 80 of 207 (39%) resected human lung tumors and that its expression is positively correlated with EGF receptor expression. Inhibition of the Notch3 pathway using a dominant-negative receptor dramatically reduces growth in soft agar and increases growth factor dependence. We also find that Notch inhibition increases sensitivity to EGF receptor tyrosine kinase inhibition and decrease in phosphorylation of the mitogen-activated protein kinase. These observations support a role for Notch3 signaling in lung cancer, and one potential mechanism of maintaining the neoplastic phenotype is through the modulation of the EGF pathway.

Transforming Growth Factor-β and Breast Cancer Risk in Women With Mammary Epithelial Hyperplasia

BACKGROUND Transforming growth factors-beta (TGF-betas) regulate mammary epithelial cell division. Loss of expression of TGF-beta receptor II (TGF-beta-RII) is related to cell proliferation and tumor progression. Breast epithelial hyperplastic lesions lacking atypia (EHLA) are associated with a mild elevation in breast cancer risk. We investigated the expression of TGF-beta-RII in EHLA and the risk of subsequent invasive breast cancer. METHODS We conducted a nested case-control study of women with biopsy-confirmed EHLA who did not have a history of breast cancer or atypical hyperplasia of the breast. Case patients (n = 54) who subsequently developed invasive breast cancer were matched with control patients (n = 115) who did not. Formalin-fixed, paraffin-embedded sections of breast biopsy specimens of all 169 patients with EHLA were studied by immunohistochemical analysis with antibodies against TGF-beta-RII. All P values are two-sided. RESULTS Women with breast EHLA and 25%-75% TGF-beta-RII-positive cells or less than 25% TGF-beta-RII-positive cells had odds ratios of invasive breast cancer of 1.98 (95% confidence interval [CI] = 0.95-4.1) or 3.41 (95% CI = 1.2-10.0), respectively (P for trend =.008). These risks are calculated with respect to women with EHLA that had greater than 75% TGF-beta-RII expression. Women with a heterogeneous pattern of TGF-beta-RII expression in their normal breast lobular units and either greater than 75%, 25%-75%, or less than 25% positive cells in their EHLA had odds ratios for breast cancer risk of 0.742 (95% CI = 0.3-1.8), 2.85 (95% CI = 1.1-7.1), or 3.55 (95% CI = 1.0-10.0), respectively (P for trend =.003). These risks are relative to women with a homogeneous pattern of expression in their normal lobular units and greater than 75% positive cells in their EHLA. CONCLUSION This study indicates that loss of TGF-beta-RII expression in epithelial cells of EHLA is associated with increased risk of invasive breast cancer.

Utility of surfactant protein B precursor and thyroid transcription factor 1 in differentiating adenocarcinoma of the lung from malignant mesothelioma

Differentiation of malignant mesothelioma from adenocarcinoma, particularly from a lung primary, remains a difficult diagnostic problem. Surfactant protein B precursor (pro-SP-B) and thyroid transcription factor 1 (ITF-1) are expressed selectively in the normal respiratory epithelium and in adenocarcinomas of the lung. In this study, we evaluated the utility of pro-SP-B and ITF-1 in distinguishing pulmonary adenocarcinomas and malignant mesotheliomas. Immunoreactivity for pro-SP-B and TTF-1 was examined in paraffin sections of 370 primary lung carcinomas (208 adenocarcinomas, 101 squamous cell carcinomas, and 61 large cell carcinomas) and 95 malignant mesotheliomas, using a pro-SP-B antiserum and a monoclonal TTF-1 antibody with a biotin-streptavidin detection system. Immunostaining for pro-SP-B was detected in 57% of adenocarcinomas, and 20% of large cell carcinomas. Immunoreactivity for TTF-1 was shown in 76% of adenocarcinomas and 26% of large cell carcinomas. Malignant mesotheliomas and squamous cell carcinomas did not stain with either antibody. The expression of pro-SP-B and TTF-1 in adenocarcinomas of the lung but not in malignant mesotheliomas shows that pro-SP-B and TTF-1 staining is useful in differentiating these neoplasms.

Constitutive activation of Notch3 inhibits terminal epithelial differentiation in lungs of transgenic mice

Notch3 is a transmembrane receptor and a member of the Notch signaling pathway essential for cellular differentiation in a variety of developing tissues in both invertebrates and vertebrates. Emerging data support the role of the Notch signaling pathway in tumorigenesis. We have previously demonstrated the expression of Notch3 in a subset of lung adenocarcinomas. To further elucidate the role of Notch3 in development of lung cancer, we established a transgenic mouse model in which the intracellular domain of Notch3 is expressed using the surfactant protein C promoter/enhancer. Constitutive expression of Notch3 in the peripheral epithelium in the developing lung resulted in altered lung morphology and delayed development, leading to perinatal lethality in these transgenic mice. Cell-specific markers and electron microscopy examination showed that the majority of the epithelial cells are undifferentiated, with some maturation of type II pneumocytes. No type I alveolar cells were evident. Metaplasia of undifferentiated cells in the terminal airways was also observed. Although the mice did not live long enough to assess tumor development, these findings demonstrate that ectopic expression of Notch3 in airway epithelium potentially contributes to the multistep evolution of lung cancer through the inhibition of terminal differentiation.

Expression of ABCA3 in Developing Lung and Other Tissues

ABCA3 is a member of the ATP-binding cassette (ABC) family of transport proteins and is required for perinatal respiratory adaptation. Monoclonal and polyclonal antibodies were generated against a recombinant human ABCA3 peptide and used to assess its expression in the developing lung and adult tissues. Immunostaining for ABCA3 was detected at highest levels in type II epithelial cells of the lung but was also noted in other organs including liver, stomach, kidney, adrenal, pancreas, trachea, and brain. In the fetal lung, ABCA3 staining and mRNA increased prior to birth. Like other surfactant protein genes, ABCA3 expression was induced by thyroid transcription factor-1 in vitro. ABCA3 was coexpressed with SP-B and proSP-C in type II epithelial cells. ABCA3 staining was detected surrounding large, intracellular organelles consistent with its association with lamellar bodies. In the human fetal lung, ABCA3 staining was not detected prior to 22-23 weeks of gestation, except in the presence of pulmonary inflammation. ABCA3 was detected in type II epithelial cells of the human lung from 28 weeks of gestation and thereafter. Postnatally, intense ABCA3 staining was observed in hyperplastic epithelial cells relining injured airways in infants with chronic lung disease. Localization and regulation of ABCA3 in the respiratory epithelium is consistent with its proposed role in surfactant homeostasis. The role of ABCA3 in extrapulmonary tissues and organs remains to be elucidated. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

Metaplastic Spindle Cell Breast Tumors Arising within Papillomas, Complex Sclerosing Lesions, and Nipple Adenomas

Micropapillomas/papillomas and complex sclerosing lesions of the breast have been associated with a slightly increased risk for subsequent carcinoma, although benign squamous metaplasia and reactive hypercellular stroma are seen within these lesions. There are few reports of these fibrosclerotic lesions associated with metaplastic tumors. Here we describe a series of metaplastic tumors arising within fibrosclerotic breast lesions. Thirty-three metaplastic tumors associated with fibrosclerotic lesions were selected from a breast pathology consultative practice. Relevant clinical and pathological features were reviewed. Representative sections were evaluated immunohistochemically for expression of cytokeratins, vimentin, and smooth muscle and muscle-specific actins. Both the metaplastic component (spindled and squamous cells) and the glandular elements were graded. The metaplastic tumors arose within papillomas (20 cases), complex sclerosing lesions (7 cases), both papilloma and complex sclerosing lesions (3 cases), and nipple adenoma (3 cases). A majority of the metaplastic tumors showed a dominant spindle cell component with various degrees of atypia, ranging from fibromatosis-like (16 cases) to low-grade (13 cases), intermediate-grade (2 cases), and high-grade (2 cases) fibrosarcoma phenotype. Squamous metaplasia was present in 25 cases, and low-grade glandular elements, in 21 cases. Eleven tumors had a low-grade adenosquamous growth pattern. Ductal carcinoma in situ was present in 7 cases, and invasive mammary carcinoma, in 5 cases. The very low-grade tumors were histologically similar to limited areas of stromal reaction and myofibroblastic proliferation, seen in partially sclerotic micropapillomas/papillomas and complex sclerosing lesions, but usually more cellular. Cytokeratin positivity (13+/13 tested) supports the metaplastic nature of the more plump spindled cells. The spindle cells were also positive for vimentin (8+/8 tested) and smooth muscle (2+/5 tested) and muscle-specific actins (6+/6 tested). Spindle cell metaplastic tumors, from fibromatosis-like to fibrosarcoma, may arise within a variety of fibrosclerotic breast lesions.

IgG4 plasma cells in inflammatory myofibroblastic tumor: inflammatory marker or pathogenic link?

Inflammatory myofibroblastic tumor is a rare mesenchymal neoplasm that harbors an anaplastic lymphoma kinase (ALK) gene rearrangement in the majority of cases. It is composed of fibroblastic–myofibroblastic cells with a characteristic inflammatory infiltrate that consists predominantly of plasma cells. In contrast, IgG4-related sclerosing disease is a recently described multisystem disorder with a histological appearance similar to inflammatory myofibroblastic tumor. The plasma cell infiltrate is characteristic in IgG4-related sclerosing disease and has been studied as a tool to render this diagnosis. Histologically, the two disorders overlap, although there are significant clinical differences. This study analyzes the histological appearance of 36 inflammatory myofibroblastic tumors, compares them with IgG4-related sclerosing disease, and assesses the plasma cell profile using immunohistochemistry to determine the range and proportion of IgG4 plasma cells. The majority of patients were children and young adults, mainly with solitary masses and no clinical manifestations of IgG4-related sclerosing disease. ALK-1 positivity was present in 23 cases (64%). None showed obliterative phlebitis or prominent lymphoid aggregates. Of 36 inflammatory myofibroblastic tumors, 15 cases showed an IgG4/IgG ratio ≥0.10, a cutoff described in the literature as supportive of IgG4-related sclerosing disease and up to 33 IgG4-positive plasma cells per high-power field indicating a mild-to-moderate increase as compared with IgG4-related sclerosing disease. Currently, the diagnostic recognition of inflammatory myofibroblastic tumor is based on clinicopathological features and diagnostic adjuncts, such as ALK-1 reactivity and genetic tests. Although inflammatory myofibroblastic tumor and IgG4-related sclerosing disease are distinct entities, a subset of inflammatory myofibroblastic tumors exhibit an IgG4/IgG ratio that is within the range for IgG4-related sclerosing disease. Therefore, the ratio alone cannot be used as a reliable discriminator between these two entities and other clinical and pathologic features must always be taken into account.

Immunohistochemical expression of estrogen receptor in enlarged lobular units with columnar alteration in benign breast biopsies: a nested case-control study.

The prognostic and therapeutic implications of estrogen receptor (ER) status in breast cancer are well known. Whether ER status plays a role in benign breast lesions and the progression to malignancy has not been proven. Enlarged lobular units with columnar alteration (ELUCA), also known as unfolded lobular units, have been associated with mild elevations in subsequent breast cancer risk. We examined the association of ERα expression in ELUCA with invasive breast cancer risk. A nested case-control study was performed of women with ELUCA who had undergone benign breast surgery. Eighty-two women who developed invasive breast cancer on follow-up were matched by age and year of biopsy with 166 women who did not develop invasive breast cancer. Entry biopsies were stained for ERα (clone 6F11) without knowledge of subsequent cancer outcome. ELUCA lesions were scored as positive if greater than 10% of epithelial nuclei stained with ERα and at least one ELUCA contained >50% of cells staining for ERα. Relative risks of breast cancer were estimated by odds ratios derived from conditional logistic regression analyses. Thirty-nine percent of cases and 56% of controls had positive ERα staining in ELUCA. The relative risk of invasive breast cancer in women with ERα-negative ELUCA was 1.85 times that of women with ERα-positive lesions (95% confidence interval, 1.0-3.4, P = 0.04). The presence of ERα staining in women with ELUCA is associated with a lower risk of developing subsequent invasive carcinoma. These findings have implications for risk assessment in benign breast biopsies and are of particular interest given the controversy currently surrounding hormone replacement therapy.

Elevation of AKR7A2 (succinic semialdehyde reductase) in neurodegenerative disease

Elevated levels of oxidative stress or decreased antioxidant defense mechanisms may underlie the regionally increased oxidative damage to brain observed in many neurodegenerative disorders. Phase I detoxification pathways for reactive aldehydes generated from lipid peroxidation include aldehyde dehydrogenases, alcohol dehydrogenases and aldo-keto reductases (AKR). In the present study, we examined the cellular expression of AKR family member, succinic semialdehyde reductase (AKR7A2) that reduces toxic aldehydes as well as catalyzing the biosynthesis of the neuromodulator gamma-hydroxybutyrate (GHB). Our results show that in the cerebral cortex and hippocampus, AKR7A2 is primarily localized to glial cells, astrocytes and microglia. In the midbrain, AKR7A2 was found in glia and neuromelanin-containing neurons of the substantia nigra, and the periaqueductal gray. In sections of cerebral cortex and hippocampus from patients with AD and DLB, AKR7A2 immunoreactivity was elevated in reactive astrocytes and microglial cells. Furthermore, total AKR7A2 protein levels were elevated in the cerebral cortex of patients with AD versus control individuals. Our data suggest that reactive gliosis, as a response to injury, may affect GHB neuromodulatory pathways in neurodegenerative disease and elevate aldehyde detoxification pathways.