Abstract P2-05-04: Comparative expression profiling of patient samples and preclinical models of inflammatory breast cancer reveals gene signatures of epithelial plasticity and suppression of TGFb signaling

Introduction: Genome-wide expression profiling of samples from patients with and without Inflammatory Breast Cancer (IBC) has revealed novel insights into the biology of IBC. The present study was undertaken to compare these novel insights with data obtained from all available preclinical IBC models including 2 new models that we have recently developed that recapitulate the characteristics of IBC including retention of E-cadherin, formation of tumor emboli and encircling lymphoangiogenesis

Materials and Methods: Five replicates of 7 preclinical IBC models (SUM149, SUM190, FC-IBC-01, FC-IBC-02, MDA-IBC-03, KPL-4, and Mary-X) were profiled using Affymetrix HGU133plus2 GeneChips. Using a nearest shrunken centroid algorithm, each expression profile was classified according to an IBC-specific signature identified in patient samples. Available expression profiles were further queried for expression patterns related to Epithelial-to-Mesenchymal Transition (EMT), TGFβ-signaling and IBC-specific patterns of transcription factor activation.

Results: Application of our IBC-specific signature (posterior probabilities exceeded 0.50 in at least 4/5 replicates) revealed that out of 7 pre-clinical models of IBC, 3 of these robustly classified as IBC (FC-IBC-01, FC-IBC-02, and KPL-4). All preclinical IBC models were characterized by retention of E-Cadherin expression, absence of ZEB1 expression, attenuated expression of specific components of the TGFβ pathway (TGFβR2, SMAD3, SMAD7, and TGFβ1), and ambiguous activation patterns of several transcription factors involved in regulating cellular plasticity and cell fate decisions (Up in IBC: NR4A2, RARB/RXRA, PTX3, GSC2, and ZEB1; Down in IBC: SOX10, PAX5, and SMAD2). For each of the molecular alterations described above, Z-scores greater than 2 were achieved in at least 4/5 replicates.

Conclusions: The observations that we have made using IBC patient tumor samples with regards to EMT, cell plasticity and TGFβ-signaling are corroborated in pre-clinical models of IBC using current analytic approaches, despite the fact that expression patterns of the majority of preclinical models of IBC deviate from the IBC-specific expression patterns observed in patient samples. Our data suggest that despite their highly invasive nature, IBC cancer cells retain an epithelial cell phenotype characterized by E-cadherin expression and loss of ZEB1 which appears to be mediated by, amongst others, attenuated TGFβ-signaling. This study strengthens our hypothesis that cancer cells from IBC exhibit cohesive invasion, and invade as a unit, possibly explaining the presence of florid tumour emboli which is a primary characteristic observed in IBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-05-04.

Abstract P6-10-04: The Presence of Anaplastic Lymphoma Kinase Recapitulates Formation of Breast Tumor Emboli with Encircling Lymphovasculogenesis

Background: Genetic abnormalities in the anaplastic lymphoma kinase (ALK) gene result in activation of signaling pathways including Akt, mTor, and JAK/Stat3. ALK has been shown to be a primary oncogenic driver in a variety of human tumors, including both hematologic malignancies such as anaplastic large cell lymphoma, as well as solid tumors including neuroblastoma, non-small cell lung cancer, myofibroblastic tumors and most recently, high grade serous ovarian carcinoma. While only ∼3% of all breast cancers have been reported to have ALK genetic abnormalities, our studies revealed that inflammatory breast cancer (IBC), the most lethal variant of breast cancer, is characterized by prevalent ALK gene amplification with activated ALK signaling. The present studies investigated the role of ALK in breast cancer by expressing full-length wild type ALK in MCF-7 cells.

Materials and Methods: Clones of MCF-7 breast cancer cells expressing wild type ALK or non-target vector were produced by lentivirus infection and selection of single cell clones. MCF-7 ALK clones were evaluated using live cell and phase contrast imaging, immunofluorescent staining with confocal imaging, gene profiling, phospho-protein array analysis, western blot and ELISA validation. In vivo studies were performed by injection of MCF-7 ALK clones into using NOD. Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice using IACUC approved animal protocols.

Results: When cultured on plastic substrates, MCF-7 ALK clones formed tumor cell aggregates instead of monolayer cultures, and when cultured as tumor spheroids under non-adherent 3D conditions had a distinct cellular phenotype with significantly greater clonogenicity than either non-target vector MCF-7 clones or the parental cell line. Whole transcriptome analysis, with validation using protein arrays, western blots and ELISA analysis revealed that the presence of ALK up-regulated phospho-src. In vivo studies revealed that ALK expressing MCF-7 clones formed tumor emboli that were enwrapped by dermal lymphatic vessels, essentially recapitulating the phenotype of IBC tumor emboli that exhibit encircling lymphovasculogenesis. Enforced expression of wild type ALK in another breast cancer cell line resulted in similar formation of tumor emboli.

Discussion: These studies provide first time evidence for the association between full length ALK and formation of highly invasive tumor emboli enwrapped by lymphatic vessels, which is a primary characteristic of IBC. These studies, taken together with discovery of the prevalence of ALK gene amplification in IBC patients, indicate that ALK represents an important therapeutic target for IBC, with the availability of new ALK targeted therapies to evaluate as single agents and in combinations with other agents that may effectively target IBC tumor emboli that we have now linked to ALK and which represent the metastatic lesion of this lethal variant of breast cancer.

Funding by Susan G. Komen Organization Promise Grant KG081287 (FMR and MC).

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-10-04.

P4-03-06: Development and Comparative Characterization of Metastasis in Newly Developed Pre-Clinical Models of Inflammatory Breast Cancer

Background: Inflammatory breast cancer (IBC) is the most metastatic variant of breast cancer. It is associated with a poor survival rate (40% 5-year survival) despite appropriate multidisciplinary care. For such an aggressive type of cancer, IBC has been understudied, in part due to the lack of adequate numbers of cell lines and mouse models that recapitulate the human disease. To expand our understanding of IBC, we have obtained all of the previously developed and characterized IBC cell lines and models including Mary-X, SUM149, SUM190, KPL-4, MDA-IBC-3 and have developed two new IBC models, designated as FC-IBC01 and FC-IBC02, using tumor cells derived from pleural effusion of IBC patients.

Materials and Methods: Each of these IBC cell lines has been luciferase (LUC)-tagged, allowing the growth of orthotopic injection or subcutaneous implantation to be evaluated by bioluminescent imaging (BLI). Alternatively, the LUC-tagged IBC cells can by injected via either intra-cardiac or intravenous route of delivery, which promotes rapid tumor colonization, resulting in both visceral and skeletal metastasis. Growth of IBC tumors can then be monitored immediately using BLI, thus eliminating the lag time needed for the physical detection of palpable tumors. BLI imaging also allows for monitoring of the kinetics and location of development of metastatic lesions. Whole transcriptome analysis was performed on IBC cell lines and xenograft tissues to define the heterogeneity of IBC as a distinct variant of breast cancer

Results: These models have allowed us to identify micro-metastatic foci in multiple sites distant from the IBC primary tumor in each of these models of IBC and allow the quantitation of anti-tumor and anti-metastatic effects of targeted therapeutics as single agents as well as the potential synergy of combinations of agents. As an example, injection of LUC-tagged IBC cell lines such as SUM149-Luc, into the left ventricle of NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice allows the metastatic tumor burden to be monitored longitudinally by whole animal BLI, which can be validated at necropsy and by immunohistochemical analysis. Whole transcriptome analysis of pre-clinical models of IBC reflect the molecular subtypes observed in IBC patients, with the majority of IBC models being of the basal like, luminal B and Her2 amplified. Discussion: First time analysis of known and newly developed pre-clinical models of IBC allows a more complete analysis of IBC as a distinct variant of breast cancer. Furthermore, these approaches allow rapid evaluation of the promising targeted therapeutics identified based on whole transcriptome analysis of both IBC patient tumors and pre-clinical models developed from IBC patients. We believe that this extensive collection of LUC-tagged IBC cell lines is an invaluable tool for IBC research since the cell lines encompass the broad spectrum of IBC heterogeneity.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-03-06.

A role for nucleotides in support of breast cancer angiogenesis: heterologous receptor signalling

Background:

Human breast carcinoma cells secrete an adenosine 5′-diphosphate transphosphorylase (sNDPK) known to induce endothelial cell tubulogenesis in a P2Y receptor-dependent manner. We examined sNDPK secretion and its effects on human endothelial cells.

Methods:

Nucleoside diphosphate kinase (NDPK) secretion was measured by western blot and enzyme-linked immunosorbent assay, while transphosphorylase activity was measured using the luciferin-luciferase ATP assay. Activation of MAPK was determined by western blot analysis, immunofluorescence and endothelial cell proliferation and migration.

Results:

A panel of breast cancer cell lines with origin as ductal carcinoma, adenocarcinoma or medullary carcinoma, secrete sNDPK-A/B. Addition of purified NDPK-B to endothelial cultures activated VEGFR-2 and Erk_1/2, both of which were blocked by inhibitors of NDPK and P2Y receptors. Activation of VEGFR-2 and ErK_1/2 by 2-methylthio-ATP (2MeS-ATP) was blocked by pretreatment with the P2Y₁-specific antagonist MRS2179, the proto-oncogene non-receptor tyrosine kinase (Src) inhibitor PP2 or the VEGFR-2 antagonist SU1498. Nucleoside diphosphate kinase-B stimulates cell growth and migration in a concentration-dependent manner comparable to the effect of vascular endothelial growth factor. Treatment of endothelial cells with either NDPK-B or 2MeS-ATP induced migration, blocked by P2Y₁, Src or VEGFR-2 antagonists.

Conclusion:

sNDPK supports angiogenesis. Understanding the mechanism of action of sNDPK and P2Y₁ nucleotide signalling in metastasis and angiogenesis represent new therapeutic targets for anti-angiogenic therapies to benefit patients.

Abstract P5-05-04: E-Cadherin and Its Proteolytic Fragments Trump Epithelial-Mesenchymal Transition and Function as Dominant Oncogenes in Inflammatory Breast Cancer

Background: Inflammatory breast cancer (IBC) and its lymphovascular embolic signature seem to challenge the dogma of prerequisite epithelialmesenchymal transition (EMT) in human breast cancer progression by the apparent maintenance of an epithelial state in all stages of IBC. Previous studies with a human xenograft model of inflammatory breast cancer, MARY-X, demonstrated that overexpressed E-cadherin moderated the formation of the lymphovascular embolus in vivo and tumoral spheroids of super-high density in vitro. Although slug, snail and twist are increased in MARY-X spheroids and may decrease E-cadherin transcription to some extent, their effects are neutralized and frankly overridden by the post-transcriptional regulation of E-cadherin which includes its altered degradation and trafficking which, in turn, maintain the epithelial state. Materials and Methods: Because of the uniqueness of the MARY-X model and the observation that E-cadherin was not functioning as a tumor suppressor gene whose loss was triggering EMT but rather whose overexpression was mediating increased survival and resistance to apoptosis, we decided to examine the fate and role of E-cadherin more closely.

Results: We discovered that E-cadherin underwent extensive proteolytic processing which resulted in fragments also mediating increased survival and resistance to apoptosis. In both MARY-X and the MARY-X spheroids, Western blot revealed 5 E-cadherin bands: one full length (120 kDa) and four fragments: E-cad/NFT1 (100 kDa), E-cad/NTF2 (95 kDa), E-cad/NTF3 (85 kDa), E-cad/NTF4 (80kDa). Corresponding E-cad/CTF1-4 fragments were also generated. Compared to MARY-X, NFT1 was dramatically increased in the MARY-X spheroids whereas NFT2-4 were significantly decreased. These E-cadherin fragments were produced by specific proteolytic cleavage based on inhibitor studies: NFT1 was produced by calpain, NFT2 by γ-secretase, NFT3 by a matrix metalloproteinase and NFT4 by an unknown mechanism. Predictably levels of calpain activity were significantly increased in the MARY-X spheroids. NFT1 generatedby increased calpain activity retained the p120ctn binding site but lost both the β-catenin and α-binding sites, facilitating its 360° distribution around the cell. Calpain inhibition decreased NFT1 without any affect on full length E-cadherin yet induced disadherence of intact spheroids and prevented the assembly of de novo spheroids. Identical proteolytic fragments of E-cadherin were observed in 3 other human IBC cell lines as well as in lymphovascular emboli of human IBC cases obtained by laser capture microdissection.

Discussion: The selective proteolytic processing of E-cadherin ultimately then is responsible for the increased survival of the lymphovascular embolus of IBC and its resistance to chemotherapy-induced apoptosis. Select NT proteolytic fragments may function as adhesion molecules whereas select CT proteolytic fragments may function as transcription factors which confer this survival advantage. E-cadherin and its proteolytic fragments then both trump EMT as well as function as dominant oncogenes in IBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-04.

The lymphovascular embolus of inflammatory breast cancer exhibits a Notch 3 addiction

Inflammatory breast carcinoma (IBC) is characterized by exaggerated lymphovascular invasion (LVI), recapitulated in our human xenograft, MARY-X. This model exhibited lymphovascular emboli in vivo and corresponding spheroids in vitro. Owing to the morphological and gene profile resemblance of these spheroids to embryonal blastocysts, we wondered whether they might exhibit embryonic stem cell signaling. Specifically we investigated Notch and observed selective Notch 3 activation by expression profiling, reverse transcriptase- and real-time PCR, western blot and immunofluorescence in vitro, and immunohistochemistry in vivo. Notch 3 intracellular domain (N3icd) and six target genes, HES-5, HEY-1, c-Myc, Deltex-1, NRARP and PBX1, markedly increased in MARY-X. In addition, a significant percentage of MARY-X cells expressed aldehyde dehydrogenase (ALDH), a stem cell marker. Only the ALDH(+) cells were capable of secondary spheroidgenesis, tumorigenicity and self-renewal. Inhibiting Notch 3 activation in vitro with γ-secretase inhibitors (GSIs) or small interfering RNA resulted in a downregulation of Notch target genes, including CD133, and an induction of caspase 3-mediated apoptosis. Transfection of N3icd but not Notch 1 intracellular domain into normal human mammary epithelial cells resulted in increased expression of Notch target genes and induction of spheroidgenesis. GSI in vivo resulted in inhibitory but diffusion-limited effects on Notch 3 signaling, resulting in xenograft growth reduction. The lymphovascular emboli of human IBC exhibited dual N3icd and ALDH1 immunoreactivities independently of molecular subtype. This Notch 3 addiction of lymphovascular emboli might be exploited in future therapeutic strategies.

The laminin receptor and basement membrane dissolution: role in tumour metastasis

Tumour invasion and metastasis is a complex process involving multiple interactions of tumour cells with host cellular and extracellular elements. Metastasizing tumour cells traverse basement membranes at many stages in the metastatic cascade. Immunohistology studies demonstrate that the basement membranes are defective in all human malignant epithelial neoplasms studied to date. The basement membrane is absent in regions of microinvasion and adjacent to actively invading tumour cells. In contrast, benign neoplasms retain a continuous basement membrane. This distinction may have diagnostic value in surgical pathology. Tumour cells are hypothesized to traverse basement membranes by a three-step process: attachment, local degradation of the basement membrane by type IV collagenase and other proteases, and locomotion. The first step may be mediated in part by specific cell surface receptors which bind to laminin in the basement membrane. The laminin receptor has been purified from a series of different human carcinomas. The receptor has an Mr of 67 000 and a binding coefficient of 2 nM. The content of unoccupied receptors is markedly augmented in invasive human breast cancer compared to benign controls.

Semi-automated imaging system to quantitate estrogen and progesterone receptor immunoreactivity in human breast cancer

A semi-automated imaging system is described to quantitate estrogen and progesterone receptor immunoreactivity in human breast cancer. The system works for any conventional method of image acquisition using microscopic slides that have been processed for immunohistochemical analysis of the estrogen receptor and progesterone receptor. Estrogen receptor and progesterone receptor immunohistochemical staining produce colorimetric differences in nuclear staining that conventionally have been interpreted manually by pathologists and expressed as percentage of positive tumoral nuclei. The estrogen receptor and progesterone receptor status of human breast cancer represent important prognostic and predictive markers of human breast cancer that dictate therapeutic decisions but their subjective interpretation result in interobserver, intraobserver and fatigue variability. Subjective measurements are traditionally limited to a determination of percentage of tumoral nuclei that show positive immunoreactivity. To address these limitations, imaging algorithms utilizing both colorimetric (RGB) as well as intensity (gray scale) determinations were used to analyze pixels of the acquired image. Image acquisition utilized either scanner or microscope with attached digital or analogue camera capable of producing images with a resolution of 20 pixels /10 mu. Areas of each image were screened and the area of interest richest in tumour cells manually selected for image processing. Images were processed initially by JPG conversion of SVS scanned virtual slides or direct JPG photomicrograph capture. Following image acquisition, images were screened for quality, enhanced and processed. The algorithm-based values for estrogen receptor and progesterone receptor percentage nuclear positivity both strongly correlated with the subjective measurements (intraclass correlation: 0.77; 95% confidence interval: 0.59, 0.95) yet exhibited no interobserver, intraobserver or fatigue variability. In addition the algorithms provided measurements of nuclear estrogen receptor and progesterone receptor staining intensity (mean, mode and median staining intensity of positive staining nuclei), parameters that subjective review could not assess. Other semi-automated image analysis systems have been used to measure estrogen receptor and progesterone receptor immunoreactivity but these either have required proprietary hardware or have been based on luminosity differences alone. By contrast our algorithms were independent of proprietary hardware and were based on not just luminosity and colour but also many other imaging features including epithelial pattern recognition and nuclear morphology. These features provide a more accurate, versatile and robust imaging analysis platform that can be fully automated in the near future. Because of all these properties, our semi-automated imaging system 'adds value' as a means of measuring these important nuclear biomarkers of human breast cancer.

Fiberoptic ductoscopy for breast cancer patients with nipple discharge

BACKGROUND

Breast cancer and precancer are thought to originate in the lining of the milk duct, but until recently, we have not had direct access to this area other than in tissue removed blindly by core biopsy or fine-needle aspiration. Fiberoptic ductoscopy (FDS) is an emerging technique that allows direct visual access of the ductal system of the breast through nipple orifice cannulation and exploration. To date, this technique has been used only in pilot studies. Previously, we have demonstrated that fiberoptic ductoscopy in patients with and without nipple discharge is a safe and effective means of visualizing the intraductal lesion. When combined with cytology, it is a screening technique that has high predictive value.

METHODS

We applied ductoscopy to 415 women with nipple discharge with the specific intent of detecting those patients with nipple discharge who had intraductal carcinoma (DCIS) as the basis of their discharge.

RESULTS

In this cohort of patients, ductoscopy was successful in visualizing an intraductal lesion in 166 patients (40%). In these cases, ductal lavage following ductoscopy increased the yield of cytologically interpretable ductal epithelial cells 100-fold compared to discharge fluid alone. In the majority of these patients, FDS examination detected lesions that had the appearance of typical papillomas. However, in 10 patients, the intraductal lesion exhibited one of several atypical features, including bleeding, circumferential obstruction, and gross fungating projections. In eight of these patients, the subsequent histopathology turned out to be DCIS. In two of these eight patients, endoscopic biopsy revealed cytologically malignant cells; in two others, ductal lavage (washings) revealed cytologically malignant cells. In three additional patients, although FDS examination uncovered a typical papilloma that was not biopsied, ductal lavage (washings) revealed cytologically malignant cells. On surgical pathology review of the extirpated lesions, all 11 patients were subsequently shown to have DCIS. Of these 11 cases of DCIS that were initially detected with a combination of FDS and ductal lavage cytology, six were completely negative on mammogram and physical exam.

CONCLUSION

Although nipple discharge is an unusual presentation for DCIS, in patients with nipple discharge, FDS with ductal lavage cytology is a useful technique for diagnosing DCIS prior to definitive surgery.

An intact overexpressed E-cadherin/alpha,beta-catenin axis characterizes the lymphovascular emboli of inflammatory breast carcinoma

The step of intravasation (lymphovascular invasion), a rate-limiting step in metastasis, is greatly exaggerated in inflammatory breast carcinoma (IBC). Because nearly all human breast carcinoma cell lines grow as solitary nodules in nude/severe combined immunodeficient mice without manifesting lymphovascular invasion, this step has been difficult to study. We captured the essence of the IBC phenotype by establishing a unique human transplantable IBC xenograft, MARY-X, which manifests florid lymphovascular emboli in severe combined immunodeficient/nude mice. Comparing MARY-X with common non-IBC cell lines/xenografts, we discovered an overexpressed and overfunctioning E-cadherin/alpha,beta-catenin axis. In MARY-X, the E-cadherin and catenins were part of a structurally and functionally intact adhesion axis involving the actin cytoskeleton. In vitro, MARY-X grew as round compact spheroids with a cell density 5-10-fold higher than that of other lines. The spheroids of MARY-X completely disadhered when placed in media containing absent Ca(2+) or anti-E-cadherin antibodies or when retrovirally transfected with a dominant-negative E-cadherin mutant (H-2K(d)-E-cad). Anti-E-cadherin antibodies injected i.v. immunolocalized to the pulmonary lymphovascular emboli of MARY-X and caused their dissolution. H-2K(d)-E-cad-transfected MARY-X spheroids were only weakly tumorigenic and did not form lymphovascular emboli. A total of 90% of human IBCs showed increased membrane E-cadherin/alpha,beta-catenin immunoreactivity. These findings indicate that it is the gain and not the loss of the E-cadherin axis that contributes to the IBC phenotype.

Myoepithelial-specific CD44 shedding is mediated by a putative chymotrypsin-like sheddase

Our previous studies have demonstrated that myoepithelial cells, which surround incipient carcinomas in situ of the breast and other organs, exert antiinvasive and antiangiogenic effects in vitro through the elaboration of a number of different suppressor molecules among which include the shed membrane CD44. The present study addresses the mechanism of this myoepithelial CD44 shedding. This CD44 shedding is enhanced by PMA pretreatment, is specific for myoepithelial CD44, and inhibited by chymotrypsin-like inhibitors (chymostatin, alpha(1)-antichymotrypsin, TPCK, and SCCA-2) but not by trypsin-like inhibitors (TLCK), nor papain-like inhibitors (SCCA-1) nor hydroxamate-based or general metalloproteinase inhibitors (BB2516 (marimastat), 1,10-phenanthroline, and TIMP-1). The effect of PMA can be mimicked by exogenous chymotrypsin but not by other proteases. The CD44 shedding activity cannot be transferred by conditioned media, cell-cell contact, peripheral membrane, or integral membrane fractions. However, cell-free purified integral plasma membrane fractions obtained from myoepithelial cells pretreated with PMA also exhibit CD44 shedding which is inhibited by chymotrypsin-like inhibitors. These findings support the presence and activation of a putative chymotrypsin-like sheddase as the mechanism of CD44 shedding in myoepithelial cells.

Myoepithelial-specific CD44 shedding contributes to the anti-invasive and antiangiogenic phenotype of myoepithelial cells

Myoepithelial cells surround incipient ductal carcinomas of the breast and exert anti-invasive and antiangiogenic effects in vitro through the elaboration of suppressor molecules. This study examines one putative molecule, solubilized CD44 produced by myoepithelial shedding of membrane CD44. Studies with different human myoepithelial cell lines demonstrate that myoepithelial cells express and shed both the 85-kDa standard (CD44s) and the 130-kDa epithelial (CD44v8-10) isoforms, findings further confirmed by the use of isoform-specific antibodies. PMA pretreatment enhances CD44 shedding detected by two different methods at different time points: a reduction in surface CD44 at 2 h by flow cytometry and a marked decrease in both total cellular CD44 and plasma membrane CD44 at 12 h by Western blot. This shedding is both specific for CD44 and specific for myoepithelial cells. This shedding is inhibited by the chymotrypsin inhibitors chymostatin and alpha(1)-antichymotrypsin but not by general metallo-, cysteine, or other serine proteinase inhibitors. Myoepithelial-cell-conditioned medium and affinity-purified solubilized CD44 from this conditioned medium block hyaluronan adhesion and migration of both human carcinoma cell lines and human umbilical vein endothelial cells.

Fiberoptic ductoscopy for patients with nipple discharge

BACKGROUND

Breast carcinoma and precancer are thought to start in the lining of the milk duct or lobule, yet until recently, we have not had direct access to this area other than by blindly removing tissue by core biopsy or fine-needle aspiration. Fiberoptic ductoscopy (FDS) is an emerging technique allowing direct visual access to the ductal system of the breast through nipple orifice exploration.

METHODS

We applied ductoscopy to 259 women who had nipple discharge, and we analyzed the visual findings, the cytological washings, and the subsequent histopathology.

RESULTS

In 92 (36%) of these women, fiberoptic ductoscopy was successful in detecting an intraductal papillary lesion. Of these observed lesions, 68 (74%) were single papilloma, 21 (23%) were multiple discrete papillomas, and 3 (3%) were diffuse intraductal thickening which corresponded to diffuse papillomatosis on histopathological analysis. The overall positive predictive value of FDS screening was 83%. Of the lesions observed, 29.8% were located in the main (segmental) duct, 43.9% lesions in the first branch, 17.5% lesions in the second branch, 7.9% in the third branch, and 0.9% in the fourth branch. These lesions had an overall average distance of 2.7 cm from the nipple orifice. Ductal washings performed at the time of ductoscopy were effective at obtaining representative exfoliated ductal cells which could be evaluated for the presence of clumps (> 50 cells), clumps with atypia or single ductal cells. The presence of clumps with positive FDS increased the positive predictive value to 86%.

CONCLUSIONS

Fiberoptic ductoscopy currently offers a safe alternative to ductography in guiding subsequent breast surgery in the treatment of nipple discharge.

Human breast carcinoma desmoplasia is PDGF initiated

The desmoplastic response to human breast carcinoma is a host myofibroblast-mediated collagenous response exhibiting synergistic effects on tumor progression. Although many paracrine interactions between breast carcinoma cells and myofibroblasts have been characterized, the event(s) which initiate desmoplasia have remained undefined. Our studies utilized c-rasH transfected MCF-7 cells which overexpress ras p2l and which are weakly tumorigenic in ovariectomized nude mice. The xenografts are desmoplastic and comprised of 30% myofibroblasts and 60 mg/g of interstitial collagen. In situ hybridization studies of these xenografts reveal a stromal gene expression pattern (stromelysin-3, IGF-II and TIMP-1) identical to that observed in human tumor desmoplasia. 17-beta estradiol increases c-rasH MCF-7 growth but abolishes desmoplasia. c-rasH MCF-7 in vitro constitutively produce myofibroblast mitogenic activity which competes with PDGF in a receptor binding assay. This myofibroblast mitogenic activity is unaltered by 17-beta estradiol/tamoxifen pretreatment in vitro. Transfection of c-rasH MCF-7 with a PDGF-A dominant negative mutant, 1308, produced by site-directed mutagenesis (serine-->cysteine129) reduces both homo- and heterodimer secretion of PDGF by as much as 90% but does not interfere with the secretion of other growth factors. Clones with low PDGF, though tumorigenic, are non-desmoplastic. Our results suggest that breast carcinoma-secreted PDGF is the major initiator of tumor desmoplasia.

Tamoxifen enhances myoepithelial cell suppression of human breast carcinoma progression in vitro by two different effector mechanisms

Our previous studies have indicated that myoepithelial cells surrounding ductal and acinar epithelium of glandular organs, such as the breast, exert multiple paracrine suppressive effects on incipient and developing cancers that arise from this epithelium. Myoepithelial cells and derived cell lines (HMS 1-6) exert these effects through the secretion of a number of different effector molecules that exert anti-invasive, anti-proliferative, and anti-angiogenic activities. Since previous basic and clinical studies have examined the role of estrogen agonists and antagonists on human breast cancer cells and because issues of hormone replacement therapy (HRT) and tamoxifen chemoprevention are such timely issues in breast cancer, we wondered whether or not hormonal manipulations might affect myoepithelial cells in vitro as far as their paracrine suppressive activities on breast cancer were concerned. The present in vitro study demonstrates that treatment of myoepithelial cells with tamoxifen but not 17beta-estradiol increases both maspin secretion and invasion-blocking ability. Furthermore tamoxifen but not 17beta-estradiol increases inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production by myoepithelial cells when they are co-cultured with conditioned media from or breast carcinoma cells directly. This increased myoepithelial NO exerts both autocrine and paracrine antiproliferative effects which can be blocked by inhibition of iNOS. 17beta-Estradiol, however, competes with all of these suppressive effects of tamoxifen suggesting that the mechanism of tamoxifen action is estrogen receptor mediated. Myoepithelial cells lack ER-alpha but express ER-beta. Tamoxifen, but not 17beta-estradiol, increases AP-1 CAT but not ERE-CAT activity. Again, 17beta-estradiol competes with the transcription-activating effects of tamoxifen. These experiments collectively suggest that the actions of tamoxifen on the increased secretion of maspin and increased production of NO by myoepithelial cells are mediated through ER-beta and the transcription-activation of an ER-dependent AP-1 response element.

Breast-cancer diagnosis with nipple fluid bFGF

Early diagnosis of breast cancer is the key to extending survival of breast-cancer patients. We found that the concentrations of nipple fluid bFGF (basic fibroblast growth factor) was significantly increased in breast-cancer patients compared with concentrations in controls (1717 ng/L [SD 706] vs 19 ng/L [19]; Student's t test p=0.027). Measurement of bFGF in nipple fluid could be a useful diagnostic tool for breast cancer, and deserves further study.

Evidence for a protein related immunologically to the jaagsiekte sheep retrovirus in some human lung tumours

Human bronchioloalveolar carcinoma (BAC) is a lung cancer, morphologically similar to an endemic contagious lung neoplasm of sheep called sheep pulmonary adenomatosis (SPA) or jaagsiekte. SPA is caused by an exogenous type B/D retrovirus (jaagsiekte sheep retrovirus (JSRV)), which prompted the present study to obtain evidence of a retrovirus in BAC. A panel of 249 human lung tumours, 21 nontumour lung lesions, four normal lung tissues, 23 adenocarcinomas from other organs and a cell line expressing a human endogenous retrovirus protein was examined immunohistochemically using a rabbit antiserum directed against the JSRV capsid protein. Specific staining was detected only in the cytoplasm of recognizably neoplastic cells in the pulmonary alveoli of 39 of 129 (30%) BACs, 17 of 65 (26%) lung adenocarcinomas and two of seven large cell carcinomas. The remaining samples were negative. These results support the hypothesis that some human pulmonary tumours may be associated with a jaagsiekte sheep retrovirus-related retrovirus, warranting further studies.

The human myoepithelial cell displays a multifaceted anti-angiogenic phenotype

Human myoepithelial cells which surround ducts and acini of certain organs such as the breast form a natural border separating epithelial cells from stromal angiogenesis. Myoepithelial cell lines (HMS-1-6), derived from diverse benign myoepithelial tumors, all constitutively express high levels of active angiogenic inhibitors which include TIMP-1, thrombospondin-1 and soluble bFGF receptors but very low levels of angiogenic factors. These myoepithelial cell lines inhibit endothelial cell chemotaxis and proliferation. These myoepithelial cell lines sense hypoxia, respond to low O2 tension by increased HIF-1 alpha but with only a minimal increase in VEGF and iNOS steady state mRNA levels. Their corresponding xenografts (HMS-X-6X) grow very slowly compared to their non-myoepithelial carcinomatous counterparts and accumulate an abundant extracellular matrix devoid of angiogenesis but containing bound angiogenic inhibitors. These myoepithelial xenografts exhibit only minimal hypoxia but extensive necrosis in comparison to their non-myoepithelial xenograft counterparts. These former xenografts inhibit local and systemic tumor-induced angiogenesis and metastasis presumably from their matrix-bound and released circulating angiogenic inhibitors. These observations collectively support the hypothesis that the human myoepithelial cell (even when transformed) is a natural suppressor of angiogenesis. Oncogene (2000) 19, 3449 - 3459

Genistein's "ER-dependent and independent" actions are mediated through ER pathways in ER-positive breast carcinoma cell lines

Genistein, a natural flavone found in soy has been postulated to be responsible for lowering the rate of breast cancer in Asian women. Our previous studies have shown that genistein exerts multiple suppressive effects on both estrogen receptor positive (ER+) as well as estrogen receptor negative (ER-) human breast carcinoma lines suggesting that the mechanisms of these effects may be independent of ER pathways. In the present study however we provide evidence that in the ER+ MCF-7, T47D and 549 lines but not in the ER-MDA-MB-231 and MDA-MB-468 lines both presumed "ER-dependent" and "ER-independent" actions of genistein are mediated through ER pathways. Genistein's antiproliferative effects are estrogen dependent in these ER+ lines, being more pronounced in estrogen-containing media and in the presence of exogenous 17-beta estradiol. Genistein also inhibits the expression of ER-downstream genes including pS2 and TGF-beta in these ER+ lines and this inhibition is also dependent on the presence of estrogen. Genistein inhibits estrogen-induced protein tyrosine kinase (PTK) activity. Genistein is only a weak transcriptional activator and actually decreases ERE-CAT levels induced by 17-beta estradiol in the ER+ lines. Genistein also decreases steady state ER mRNA only in the presence of estrogen in the ER+ lines thereby manifesting another suppression of and through the ER pathway. Our observations resurrect the hypothesis that genistein functions as a "good estrogen" in ER+ breast carcinomas. Since chemopreventive effects of genistein would be targeted to normal ER-positive ductal-lobular cells of the breast, this "good estrogen" action of genistein is most relevant to our understanding of chemoprevention.

Human colon cancer cells express multiple glycoprotein ligands for E-selectin

The interaction between the colon tumor cell surface and the endothelial cell layer is an important component of tumor intravasation, extravasation, and metastasis. Multiple studies suggest that tumor cells may bind to E-selectin expressed on endothelial cells during these processes. To identify possible E-selectin ligands on tumor cells that may participate in this mechanism, we used E-selectin-Ig chimera affinity chromatography to isolate glycoproteins from the human colon cancer cell line Colo-205. Binding of these cells to E-selectin was specific, required the presence of calcium, and could be blocked by antibodies against E-selectin. We identified LAMP-1 (lysosomal membrane glycoprotein-1), LAMP-2, and two high molecular weight glycoproteins (>400 kDa and 300 kDa) as the main E-selectin ligands on Colo-205 cells. Treatment of the cells with N-glycanase and O-sialoglycoprotease abolished their binding to E-selectin. The high MW glycoproteins contained sialyl Lewis X and/or sialyl Lewis A glycoconjugates, and appeared to be either alternatively spliced or alternatively glycosylated forms of MUC-1 (mucin-1).

Uterine smooth muscle tumors: utility of classification by proliferation, ploidy, and prognostic markers versus traditional histopathology

CONTEXT

Accurate categorization of uterine smooth muscle neoplasms by light microscopic examination is difficult. Multiple classification schemes have been proposed based on mitotic rate, nuclear atypia, and the presence or absence of necrosis. None of these classification systems has been entirely successful. Multiple ancillary techniques have been tested for their ability to predict behavior of uterine smooth muscle tumors.

OBJECTIVE

We assayed 45 smooth muscle neoplasms for a variety of proliferation markers, oncogene protein products, and DNA ploidy level to determine if these markers supplied prognostically useful information over and above that obtained by routine light microscopic assessment.

STUDY DESIGN

Forty-five uterine smooth muscle neoplasms were assessed for DNA ploidy; silver-staining nucleolar organizer regions (AgNORs); percent nuclear proliferating cell nuclear antigen (PCNA); expression of p53, Her-2/neu, and MDM-2 protein; mitotic rate; and nuclear grade. These markers were correlated with histologic diagnosis and the occurrence of a clinically adverse event (death, metastasis, or recurrence).

RESULTS

Diagnostic category (P <.001), nuclear grade (P <.002), mitotic activity (P <.001), mean AgNORs (P <.001), percent nuclear PCNA (P =.02), and expression of p53 (P =.02) all correlated with clinical outcome. No statistically significant correlation between clinical outcome and the categories MDM-2 expression, Her-2/neu expression, or DNA ploidy was seen. Nuclear grade, p53 expression, mitotic rate, AgNORs, and percent nuclear PCNA correlated with diagnosis.

CONCLUSIONS

Diagnostic category, mitotic rate, AgNOR counts, PCNA, and p53 expression dichotomized uterine smooth muscle neoplasms into prognostically favorable and unfavorable groups. Although highly significant, the category AgNORs was no more successful than mitotic rate in dividing uterine smooth muscle neoplasms into prognostically favorable and unfavorable groups. Expression of p53 and percent nuclear PCNA dichotomized uterine smooth muscle neoplasms into prognostic groups, but neither technique reached the level of significance achieved by mitotic rate. Our data indicate that mitotic rate and the classification system of Kempson and Bari are at least as effective as the tested markers in separating uterine smooth muscle neoplasms into prognostic categories.

Different patterns of angiogenesis in sarcomas and carcinomas

Solid tumors depend on angiogenesis for growth and metastasis. It has been shown that blood vessel density, as determined by counting the number of capillaries in clustered bursts, is a significant prognostic factor in carcinomas. It is unclear, however, whether vessel density is a prognostic factor in sarcomas. In this study, we examined angiogenesis in sarcomas of various grades and compared their vascular patterns to those of carcinomas. Microvessels were identified by von Willebrand factor staining. The matrix of multiple sarcoma and breast carcinoma specimens were extracted and subjected to Western analysis of various angiogenic factors and inhibitors. Metalloproteinase inhibitor presence was also determined by in situ hybridization. In breast carcinomas, capillaries were clustered in bursts within the stroma of the tumor, whereas the sarcoma capillaries were homogeneously distributed in the tumor stroma. Random blood vessel density per high power field in sarcomas did not correlate with patient prognosis. The matrix of sarcomas and carcinomas contained both angiogenic stimulators and inhibitors. Tissue inhibitor of metalloproteinase-1 was found predominantly in fibroblasts and myofibroblasts in the matrix of carcinoma specimens. The difference in the pattern of angiogenesis in sarcomas and carcinomas may be attributable to the presence of fibroblasts and myofibroblasts in carcinomas, resulting in the compartmentalization of bursts of angiogenic factors. The homogeneous appearance of vessel density in sarcomas observed in the present study would be the consequence of the influence of a single compartment.

A novel human xenograft model of inflammatory breast cancer

The step of intravasation or lymphovascular invasion can be a rate-limiting step in the metastatic process. Inflammatory breast carcinoma manifests an exaggerated degree of lymphovascular invasion in situ; hence, a study of its molecular basis might shed light on the general mechanism of lymphovascular invasion exhibited by all metastasizing cancers. To this end, we have established the first human transplantable inflammatory breast carcinoma xenograft (MARY-X) in scid/nude mice. Whereas all other human xenografts grew as isolated s.c. nodules, MARY-X grew exclusively within murine lymphatics and blood vessels, and these latter elements and their supporting stroma comprised, by murine Cot-1 DNA analysis, 30% of the tumor. MARY-X, like its human counterpart, exhibited striking erythema of the overlying skin. MARY-X was estrogen receptor, progesterone receptor, Her-2/neu negative and p53, epidermal growth factor receptor positive. The primary tumor of origin of MARY-X exhibited identical markers, except that about 50% of its cells exhibited Her-2/neu amplification. Comparative studies of MARY-X with noninflammatory xenografts indicated 10-20-fold overexpression of E-cadherin and MUC1, findings that were reflected in actual cases of human inflammatory breast cancer. MARY-X should allow us to further dissect out both the upstream regulatory machinery and the downstream effector molecules responsible for the inflammatory carcinoma phenotype.

Prognostic role of p27Kip1 and apoptosis in human breast cancer

Human breast carcinoma is biologically heterogeneous, and its clinical course may vary from an indolent slowly progressive one to a course associated with rapid progression and metastatic spread. It is important to establish prognostic factors which will define subgroups of patients with low vs high risk of recurrence so as to better define the need for additional therapy. Additional characterization of the molecular make-up of breast cancer phenotypes should provide important insights into the biology of breast cancer. In the present study, we investigated apoptosis, expression of p27Kip1 and p53 retrospectively in 181 human breast cancer specimens. In addition, their relevance to the biological behaviour of breast cancer was examined. Our studies found a significant association among high histological grade, high p53, low apoptosis and low p27. Our results also demonstrated that, in human breast cancer, low levels of p27 and apoptotic index (AI) strongly correlated with the presence of lymph node metastasis and decreased patient survival. In node-negative patients, however, p27 also had prognostic value for relapse-free and overall survival in multivariate analysis. Furthermore p27 and AI had predictive value for the benefits of chemotherapy. These latter observations should prompt prospective randomized studies designed to investigate the predictive role of p27 and AI in determining who should receive chemotherapy in node-negative patients.

Neo-adjuvant chemotherapy for operable breast cancer induces apoptosis

The use of neo-adjuvant chemotherapy (often referred to as pre-operative or primary chemotherapy) represents a major change in the management of breast cancer as a systemic disease. Laboratory studies have shown that many anti-cancer agents with differing modes of action achieve cytotoxic effects by inducing apoptosis. In this study, we investigated the induction of apoptosis by neo-adjuvant chemotherapy in human breast cancer. The aim was to determine whether a correlation existed between post chemotherapy apoptotic index (AI) and clinical response and patients' survival. Our results indicate that apoptosis is induced by neo-adjuvant chemotherapy and that the response is variable. Our data show that post chemotherapy AI correlated with clinical response and increased patient survival, including both relapse (disease) free survival and overall survival. Post-neo-adjuvant chemotherapy AI levels in primary breast cancer may possibly predict an individual patient's overall response.

Altered mucin expression is a field change that accompanies mucinous (colloid) breast carcinoma histogenesis

Mucinous carcinomas of the breast, so-called colloid carcinomas, exhibit better prognoses than their nonmucinous breast counterparts. This biological difference exhibited by mucinous breast carcinomas prompted us to examine the relationship of mucin expression to colloid carcinoma histogenesis. We studied 50 colloid carcinomas, 50 noncolloid cancers, and 50 normal breasts by hematoxylin-eosin (H&E) and Alcian blue staining, mucin immunohistochemistry, in situ hybridization with a battery of MUC riboprobes, and ancillary digital image analysis. We observed luminal mucin in normal ducts in 80% of colloid carcinomas compared with 10% of noncolloid carcinomas and 6% of normal breasts (P < .01). In the cases of colloid carcinoma that showed mucin-filled ducts, luminal mucin was observed in 40% of the normal ducts and acini, 40% to 75% of the ducts involved by hyperplasia, atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS), respectively, and in 50% of the co-incidental areas of cysts (mucoceles), adenosis, fibroadenoma, and intraductal papilloma (P < .01). Immunohistochemistry showed that colloid carcinomas showed strong MUC2 cytoplasmic immunoreactivity and decreased MUC1 immunoreactivity compared with noncolloid carcinomas. In situ hybridization studies indicated fivefold increased MUC2 signals and twofold increased MUC5 signals within adjacent and remote normal epithelium in only the colloid carcinoma cases (P < .01; P < .05). In these cases of colloid carcinoma, these increased MUC2 and MUC5 signals were also observed in areas of hyperplasia, ADH, DCIS, and invasive carcinoma. In contrast, the noncolloid carcinomas showed fivefold increased MUC1 signals but no increases in MUC2 or MUC5. In mixed colloid/noncolloid carcinomas, the colloid areas had identical mucin expression patterns as the pure colloid carcinomas, but there was a loss of MUC2 and MUC5 expression and a gain of MUC1 expression in the noncolloid areas that was therefore identical to the pattern observed in pure noncolloid carcinoma. In this study, we conclude that the altered expression of mucin so characteristic of colloid carcinoma is also a field change present in adjacent and remote normal breast epithelium.

Genistein exerts multiple suppressive effects on human breast carcinoma cells

Dietary genistein, a natural flavone compound found in soy, has been proposed to be responsible for the low rate of breast cancer in Asian women. The cellular mechanisms of genistein's chemopreventive effects in vio have been largely unexplored. In our previous studies, we found that genistein exerted pronounced antiproliferative effects on both estrogen receptor-positive and -negative human breast carcinoma cells through G2-M arrest, induction of p21WAF1/CIP1 expression, and apoptosis. Because chemopreventive effects need not be limited to antiproliferation, we decided to examine whether genistein exerted other suppressive effects on breast carcinoma progression. Genistein inhibited invasion in vitro of MCF-7 and MDA-MB-231 cells. This inhibition was characterized by down-regulation of MMP (matrix metalloproteinase)-9 and up-regulation of tissue inhibitor of metalloproteinase-1, the former of which was transcriptionally regulated at activation protein-1 sites in the MMP-9 promoter. Genistein's in vitro effects on MMP-9 and tissue inhibitor of metalloproteinase-1 were also demonstrated in in vivo studies in nude mouse xenografts of MDA-MB-231 and MCF-7 cells. In these xenograft studies, genistein inhibited tumor growth, stimulated apoptosis, and upregulated p21WAF1/CIP1 expression. In the MDA-MB-231 xenograft, genistein also inhibited angiogenesis by decreasing vessel density and decreasing the levels of vascular endothelial growth factor and transforming growth factor-beta1. These in vitro and in vivo studies demonstrate that genistein exerts multiple suppressive effects on breast carcinoma cells, suggesting that its mechanism of chemoprevention is pleiotropic.

Histopathologic and molecular alterations in bronchial epithelium in habitual smokers of marijuana, cocaine, and/or tobacco

BACKGROUND

Tobacco smoking has been observed to cause molecular alterations in bronchial epithelium that antedate the development of lung carcinoma. The rising prevalence of marijuana and cocaine use among young adults in the United States prompted us to investigate whether similar molecular and histopathologic alterations occur in habitual smokers of marijuana and/or cocaine who may or may not also smoke tobacco.

METHODS

Bronchoscopy was performed in 104 healthy volunteer subjects, including 28 nonsmokers and 76 smokers of one or more of the following substances: marijuana, tobacco, and/or cocaine. Bronchial mucosa biopsy specimens and brushings were analyzed for histopathologic changes, for immunohistopathologic expression of intermediate or surrogate end-point markers that are linked to an increased risk of cancer (Ki-67 [a marker of cell proliferation], epidermal growth factor receptor, p53, Her-2/neu [also known as erbB-2 and ERBB2], globular actin, and abnormal DNA ploidy). Reported P values are two-sided.

RESULTS

Smokers of any one substance or of two or more substances exhibited more alterations than nonsmokers in five to nine of the 10 histopathologic parameters investigated (all P < .05), and they exhibited more molecular abnormalities than nonsmokers. Differences between smokers and nonsmokers were statistically significant (all P < or = .01) for Ki-67, epidermal growth factor receptor, globular actin, and DNA ploidy. There was general agreement between the presence of molecular abnormalities and histopathologic alterations; however, when disagreement occurred, the molecular abnormalities (e.g., Ki-67 and epidermal growth factor receptor) were more frequently altered (all P < or = .01).

CONCLUSIONS

These findings suggest that smoking marijuana and/or cocaine, like tobacco smoking, exerts field cancerization effects on bronchial epithelium, which may place smokers of these substances at increased risk for the subsequent development of lung cancer.

The human myoepithelial cell exerts antiproliferative effects on breast carcinoma cells characterized by p21WAF1/CIP1 induction, G2/M arrest, and apoptosis

Ductal carcinoma in situ of the breast (DCIS) is surrounded by a layer of myoepithelial cells. Our previous studies have suggested that these myoepithelial cells exert paracrine tumor-suppressive effects on invasion of breast carcinoma cells. Conditioned medium (CM), concentrated 10-100x of HMS-1, HMS-3, and HMS-4, human myoepithelial cell lines, block Matrigel invasion of a series of carcinoma cell lines. Immunoprecipitation of maspin, a recently described serpin, from these CM abolishes this anti-invasive effect. Both CM and maspin-immunoprecipitated CM, however, exert equal antiproliferative effects on a series of ER+ and ER- cell lines including MCF-7, T47D, MDA-MB-231, and MDA-MB-468. These antiproliferative effects are characterized by induction of a G2/M arrest, a twofold increase in p21(WAF1/CIP1) transcription and expression, and a threefold increase in apoptosis in the breast carcinoma lines examined. The antiproliferative effects mediated by myoepithelial cell CM do not manifest themselves in an autocrine manner, are not mediated by TGF-beta1, nor involve ER- or p53-dependent pathways. Neither the antiproliferative nor the anti-invasive effects of myoepithelial cell CM is observed with nonmyoepithelial cell CM. The in vitro observations of our present study may have relevance in explaining the increased degree of apoptosis exhibited by DCIS cells in vivo. Our findings illustrate another way myoepithelial cells function as natural paracrine tumor suppressors.

Endothelium-specific expression of an E-selectin promoter recombinant adenoviral vector

BACKGROUND

E-selectin expression is very low in normal adult blood vessels, but is significantly elevated in newly formed tumor capillaries. We hypothesized that a viral vector which has transcriptional specificity for the tumor vasculature may be a tool for angiogenesis-targeted gene therapy. We therefore designed an adenoviral vector which would only be expressed in cells that transcribe the E-selectin gene.

MATERIALS AND METHODS

The E-selectin promoter was inserted into an adenoviral vector driven by the luciferase reporter gene. The resulting AdV-Esel-Luc vector was then used to transduce endothelial cells as well as other cell types, and luciferase activity measured with a luminometric assay.

RESULTS

Exposure of transduced endothelial cells to TNF-alpha (tumor necrosis factor-alpha), a known inducer of the E-selectin promoter, generated a 30-fold increase in luciferase expression compared to untreated cells (p = 0.01). Endothelial cells cultured in tumor conditioned media as an in vitro recreation of the tumor environment resulted in even higher induction of luciferase (p = 0.0001). Furthermore, many non-endothelial cell lines expressed minimal levels of luciferase when transduced with the AdV-Esel-Luc vector under identical conditions.

CONCLUSIONS

We conclude that the E-selectin promoter can be used in order to confer transcriptional specificity to an adenoviral vector. This transcriptional specificity may in the future enable us to deliver the specific expression of therapeutic genes to the tumor vasculature.

Genistein inhibits both constitutive and EGF-stimulated invasion in ER-negative human breast carcinoma cell lines

Genistein, a natural flavone compound, has been proposed to be responsible for the lower rate of breast cancer in Asian women. The cellular mechanisms of genistein's inhibition of breast cancer progression are largely unknown. In a previous study our laboratory has presented evidence that genistein inhibits cell proliferation of breast carcinoma cells, an inhibition which is associated with a specific G2/M arrest, induction of p21WAF/CIP1 expression and apoptosis. In the present study, we present experimental evidence that illustrates that the actions of genistein are not limited to anti-proliferation: we show that genistein can inhibit both constitutive as well as epidermal growth factor (EGF)-stimulated invasion in estrogen receptor (ER)-negative human breast carcinoma lines, MDA-MB-231 and MDA-MB-468. This inhibition is characterized by the down regulation of MMP-9 (92 kDa type IV collagenase) and up regulation of TIMP-1 (tissue inhibitor of metalloproteinases) and the trypsin inhibitors: protease nexin-II (PN-II) and alpha 1-antitrypsin (alpha 1-AT). The in vivo actions of genistein may therefore extend beyond those traditionally implicated in chemoprevention, e.g., antiproliferation; genistein may act in vivo by blocking additional stages of breast cancer progression such as those stages resulting in invasion and metastasis.

Minimally invasive breast carcinoma staging using lymphatic mapping with radiolabeled dextran

BACKGROUND

The sentinel lymph node is defined as the first lymph node to receive drainage from a primary tumor. Based on this concept, the authors set out to evaluate whether the status of the sentinel lymph node can accurately predict whether breast tumor cells have metastasized to the axillary lymphatic basin.

METHODS

Radiolabeled dextran was injected into the site of the breast tumor. In the operating room, a portable gamma detector probe was used to identify the exact location of the sentinel lymph node(s). After identifying and excising the radioactive sentinel lymph node specimens, a routine axillary lymph node dissection was performed. All lymph nodes were then subjected to hematoxylin and eosin (H & E) staining, and the sentinel lymph nodes were subjected to additional cytokeratin immunohistochemistry.

RESULTS

Of the 41 patients who participated in the study, 18 had tumor metastasis to their axillary lymph nodes. In all 18 of these cases, the sentinel lymph node(s) contained cancer detected by either H & E staining or cytokeratin immunohistochemistry.

CONCLUSIONS

The status of the sentinel lymph node(s) appears to predict accurately whether breast tumor cells have metastasized to the axillary lymphatic basin. This new, minimally invasive technique for staging breast carcinoma should be further validated in a large, multi-institutional clinical trial.

Genistein inhibits proliferation similarly in estrogen receptor-positive and negative human breast carcinoma cell lines characterized by P21WAF1/CIP1 induction, G2/M arrest, and apoptosis

Genistein has been proposed to be responsible for lowering the rate of breast cancer in Asian women but the mechanism for this chemopreventive effect in vivo is unknown. In this study, we present in vitro evidence that genistein inhibits cell proliferation similarly in ER-positive and ER-negative human breast carcinoma cell lines. This inhibition is associated with specific G2/M arrest and induction of p21WAF1/CIP1 expression. Genistein results in a five-to six-fold increase in p21WAF1/CIP1 mRNA levels and a three- to four-fold increase in protein levels, only a 1.5-fold increase in p21WAF1/CIP1 transcription but a three- to six-fold increase in p21WAF1/CIP1 mRNA stability. The increase in p21WAF1/CIP1 is followed by increased apoptosis. The similar effects of genistein on a number of breast carcinoma cell lines with different ER and p53 status suggest that the actions of genistein reported here are mediated through ER and p53 independent mechanisms. The chemopreventive effects of genistein in vivo could be mediated along an identical or similar anti-proliferative pathway.

Airway inflammation in young marijuana and tobacco smokers

Forty healthy young subjects, ages 20 to 49 yr, underwent videobronchoscopy, mucosal biopsy, and bronchial lavage to evaluate the airway inflammation produced by habitual smoking of marijuana and/or tobacco. Videotapes were graded in a blinded manner for central airway erythema, edema, and airway secretions using a modified visual bronchitis index. The bronchitis index scores were significantly higher in marijuana smokers (MS), tobacco smokers (TS), and in combined marijuana/tobacco smokers (MTS), than in nonsmokers (NS). As a pathologic correlate, mucosal biopsies were evaluated for the presence of vascular hyperplasia, submucosal edema, inflammatory cell infiltrates, and goblet cell hyperplasia. Biopsies were positive for two of these criteria in 97% of all smokers and for three criteria in 72%. By contrast, none of the biopsies from NS exhibited greater than one positive finding. Finally, as a measure of distal airway inflammation, neutrophil counts and interleukin-8 (IL-8) concentrations were determined in bronchial lavage fluid. The percentage of neutrophils correlated with IL-8 levels and exceeded 20% in 0 of 10 NS, 1 of 9 MS, 2 of 9 TS, and 5 of 10 MTS. We conclude that regular smoking of marijuana by young adults is associated with significant airway inflammation that is similar in frequency, type, and magnitude to that observed in the lungs of tobacco smokers.

Humatrix, a novel myoepithelial matrical gel with unique biochemical and biological properties

Myoepithelial cells in situ and in vitro exert important paracrine effects on carcinoma cells which are mediated by high expression of extracellular matrix molecules, proteinase inhibitors and angiogenic inhibitors. Myoepithelial xenografts (human matrix secreting (HMS)-X, HMS-3X and HMS-4X) established from benign human salivary gland and breast myoepithelial tumors accumulate an abundant extracellular matrix which can be extracted with 6 M urea and 2 M guanidinium hydrochloride to form a gel at 25-37 degrees C. This gel, termed Humatrix, exhibits different biochemical and biological properties than the conventional non-human matrical gels in existence, i.e. Matrigel and Vitrogen 100. Whereas Matrigel consists mainly of basement membrane molecules, e.g. laminin, type IV collagen and heparan sulfate proteoglycan, and Vitrogen 100 consists mainly of non-basement membrane molecules, e.g. type I and type III collagen, Humatrix contains significant amounts of both basement membrane and non-basement membrane molecules, including large amounts of chondroitin sulfate proteoglycan. Like Matrigel, Humatrix contains bound growth factors, including epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I); unlike Matrigel, which contains predominantly significant quantities of bound proteinases, including tissue-type plasminogen activator (tPA), matrix metalloproteinase (MMP)-2 and MMP-9, and angiogenic factors, including basic fibroblast growth factor (bFGF) and transforming growth factor (TGF)-beta, Humatrix contains predominantly bound proteinase inhibitors such as protease nexin II (PN-II) and alpha1-antitrypsin and angiogenic inhibitors such as thrombospondin-1. Humatrix selectively stimulates the growth and tumorigenicity of human myoepithelial cell lines but inhibits invasion, angiogenesis and metastasis of other non-myoepithelial malignant cell lines. Because of its myoepithelial origin Humatrix represents a more natural source of extracellular matrix molecules and bound factors that carcinoma cells encounter in vivo.

The human myoepithelial cell is a natural tumor suppressor

Myoepithelial cells, which surround ducts and acini of glandular organs, form a natural border separating proliferating epithelial cells from basement membrane and underlying stroma. Myoepithelial cells in situ and in vitro constitutively express high amounts of proteinase inhibitors that include tissue inhibitor of metalloproteinase 1, protease nexin-II, alpha-1 antitrypsin, and maspin. Human myoepithelial xenografts (HMS-X, HMS-3X, and HMS-4X), which our laboratory has established, accumulate an abundant extracellular matrix containing sequestered proteinase inhibitors. Humatrix, a gel that we have derived from HMS-X, inhibits tumor cell invasion (down to 25% +/- 10% of Matrigel control; P < 0.01), and our recently established human myoepithelial cell lines, HMS-1, HMS-3, and HMS-4, inhibit tumor cell invasion in cellular invasion (down to 42% +/- 7% of control; P < 0.05) and in conditioned media assays (down to 30% +/- 8% of control; P < 0.01). The anti-invasive effects of HMS-1, HMS-3, and HMS-4 can be enhanced by phorbol 12-myristate 13-acetate (down to 2% +/- 1% of control) by a maspin-dependent mechanism and abolished by dexamethasone (up to 95% +/- 5% of control) by a maspin-independent mechanism (P < 0.01). HMS-X, HMS-3X, HMS-4X, and Humatrix inhibit tumor invasion and metastasis in severe combined immunodeficient mice (P < 0.001). The cumulative data suggest that myoepithelial cells are natural paracrine suppressors of invasion and metastasis and may specifically inhibit the progression of precancerous disease states to invasive cancer in vivo.

Evidence of a dominant transcriptional pathway which regulates an undifferentiated and complete metastatic phenotype

The highly metastatic amelanotic C8161 human melanoma line was found to exhibit complete dominance of its undifferentiated and metastatic phenotype in multiple somatic cell hybridization studies designed to bypass the presence of potential tumor suppressor genes. In a three armed approach involving somatic cell fusions of C8161 with recipient lines of greater differentiation, different lineage, and different tumorigenicity status, the metastatic and undifferentiated phenotype of C8161 was promiscuously dominant. In somatic cell hybrids produced between the C8161 and a group of non-metastatic human melanoma lines which exhibited melanocyte differentiation markers including S100, HMB-45, NKI/C3, and melanin, the fusions were uniformly metastatic and undifferentiated. In somatic cell hybrids of C8161 and MCF-7 the fusions exhibited an estrogen independent and unresponsive, estrogen receptor (ER) negative, and highly metastatic phenotype. In fusions between C8161 and HMS-1, an immortalized 'benign' human myoepithelial line which produced an abundant extracellular matrix (ECM) and high levels of protease and angiogenic inhibitors including maspin, tissue inhibitor of metalloproteinase-1 (TIMP-1), alpha1-antitrypsin (alpha1-AT), protease nexin II (PN-II), thrombospondin-1 and soluble basic fibroblast growth factor (bFGF) receptors, the hybrids showed complete absence of matrix, absent maspin expression, markedly decreased protease inhibitor and angiogenic inhibitor production, high levels of proteases and angiogenic factors, and a highly metastatic phenotype. In our somatic cell fusions, the human-human hybrids represented true and complete fusions and not hybrid clones selected for by loss of dominant-acting growth suppressor genes. This finding was supported by detailed comparative genomic hybridization (CGH) studies, Q-banding karyotype analysis, and autofusions of representative clones. The purposeful creation of inherently unstable human-murine fusions between C8161 and B16-F1 where loss of putative suppressor loci would be expected, resulted in fusions exhibiting decreased growth and non-metastatic behavior with progressive chromosomal loss. Neither p53, nm23, DNA methyltransferase, activated ras, fibroblast growth factor-4 (FGF-4), or epidermal growth factor receptor (EGFR) mediated the acquisition of the metastatic or undifferentiated phenotype within the C8161-human fusions. These studies are the first studies ever to successfully transfer the complete metastatic phenotype by somatic cell fusion and support the presence of a new high level regulatory pathway(s) involving dominant trans-acting factors which act pleiotropically to regulate an undifferentiated and highly metastatic phenotype.

'Revertant' DCIS in human axillary breast carcinoma metastases

Recent experimental evidence obtained in Scid mice has suggested that the metastatic process is in large part epigenetically regulated and undergoes partial reversion once the metastatic process is completed: the metastatic colonies become more engaged in the process of growing in situ than actively metastasizing. Based on this experimental evidence, examples were sought of metastatic human cancers where similar reversion to an in situ growth state was occurring. Review of 200 cases of metastatic human breast cancer revealed a 21 per cent incidence of reversion to a ductal carcinoma in situ (DCIS) growth pattern within axillary nodal metastases. The revertant DCIS areas were characterized by an intact and circumferential basement membrane, as demonstrated by extracellular laminin and type IV collagen immunoreactivity. These revertant DCIS areas could be distinguished from primary DCIS, however, by the absence of surrounding myoepithelial cells in the former, identified in the latter by their positive maspin, S-100, and smooth muscle actin immunoreactivity. The pattern of revertant DCIS, poorly differentiated (comedo) (13 per cent), intermediate (non-comedo) (6 per cent), or well-differentiated (non-comedo) (2%), exhibited complete 100 per cent concordance with the primary DCIS pattern. The concordance of histological patterns held true for even the subtypes of DCIS determined by architectural pattern, such as the micropapillary or cribriform subtypes. Nuclear size by digital image analysis and Her-2/neu, p53, and Ki-67 status in the revertant DCIS also exhibited complete concordance with the primary DCIS counterparts. Cases exhibiting a revertant DCIS pattern tended to be ER-negative/EGFR-positive and exhibited significant nodal involvement (mean number, 9; mean area, 90 per cent) compared with cases lacking a revertant pattern (mean number, 4; mean area, 15 per cent) (P < 0.01) These findings suggest that reversion of the metastatic phenotype may also be occurring within autochthonous human metastasis.

Tracheobronchial histopathology in habitual smokers of cocaine, marijuana, and/or tobacco

BACKGROUND

Marijuana and alkaloidal cocaine ("crack") are the two most commonly smoked substances in the United States after tobacco. While regular tobacco smoking has been found to be associated with extensive microscopic alterations in bronchial mucosa, little information is available concerning the effect of crack cocaine and marijuana on tracheobronchial histopathology.

STUDY OBJECTIVE

To determine the relative impact of smoked substances (cocaine, marijuana, and tobacco) alone and in combination on the histopathology of the tracheobronchial mucosa and to assess whether the effects of habitual smoking of two or more substances (cocaine, marijuana, and/or tobacco) are additive.

DESIGN

Observational cohort study.

SUBJECTS

Fifty-three nonsmoking control subjects (NS), 14 current, habitual smokers of crack cocaine only (CS), 40 current, regular smokers of marijuana only (MS), 31 regular smokers of tobacco only (TS), 16 current smokers of both cocaine and marijuana (CMS), 12 current smokers of both cocaine and tobacco (CTS), 44 current smokers of both marijuana and tobacco (MTS), and 31 current smokers of cocaine, marijuana, and tobacco (CMTS).

METHODS

After preliminary screening evaluation, including a detailed respiratory and general health questionnaire and routine pulmonary function studies, subjects underwent fiberoptic bronchoscopy with endobronchial biopsies of the mucosa of the primary carina and randomly selected secondary or tertiary carinae. Biopsy specimens were processed for light microscopy, stained with hematoxylin-eosin or periodic acid-Schiff, and examined to assess epithelial, basement membrane, and submucosal alterations by one or two pathologists who were masked to the smoking status of the subject.

RESULTS

Smokers of cocaine, marijuana, or tobacco alone all exhibited more frequent abnormalities than NS in 10 (CS) or all 11 (MS and TS) of the histopathologic features assessed. For most features, MS and TS showed significantly more frequent alterations than NS (p < or = 0.02), while CS showed significantly more frequent abnormalities than NS in only three features (p<0.05) and nearly significant differences from NS in two additional features (p < or = 0.09). Alterations were noted most frequently in CTS (six features) and MTS (three features), while abnormalities were relatively infrequent in CMS. For 10 features, MTS had more frequent alterations than MS and TS. With a single exception, CMTS did not show more frequent alterations than CTS or MTS.

CONCLUSION

Marijuana and tobacco smoking each produces significant bronchial mucosal histopathology and the effects of marijuana and tobacco appear additive. Cocaine appears to lead to fewer significant bronchial mucosal alterations than marijuana or tobacco when smoked alone and does not add to the changes associated with marijuana. When smoked together with tobacco, however, cocaine appears to augment the bronchial injury caused by tobacco smoking.

Vascular expression of E-selectin is increased in estrogen-receptor-negative breast cancer: a role for tumor-cell-secreted interleukin-1 alpha

Angiogenesis plays an important role in breast cancer growth and metastasis. Multiple adhesion molecules have been shown to perform critical functions in the process of angiogenesis. In this study, we analyzed 15 benign and 22 malignant estrogen-receptor-negative and estrogen-receptor-positive breast specimens for the presence of the endothelial cell adhesion molecules E-selectin and P-selectin. We found that E-selectin's expression was increased in the malignant breast tumors compared with their benign counterparts (23.86% of blood vessels versus 2.47%; P = 0.0005). Furthermore, E-selectin staining was found to be significantly increased in the estrogen-receptor-negative carcinomas compared with the estrogen-receptor-positive ones (P = 0.005). In vitro findings strongly correlated with the in vivo findings and showed a higher degree of E-selectin induction in endothelial cells exposed to conditioned media from estrogen-receptor-negative breast cancer cell lines than from estrogen-receptor-positive ones. The degree of E-selectin induction correlated with the amount of interleukin-1 alpha in the tumor-conditioned media. Neutralizing antibodies to interleukin-1 alpha significantly inhibited the E-selectin expression in endothelial cells exposed to tumor-conditioned media. The results indicate that the endothelial E-selectin expression during angiogenesis is related to breast carcinoma progression in vivo and that this component of angiogenesis may be due directly to tumor-cell-secreted interleukin-1 alpha.

Ectopic G-CSF expression in human melanoma lines marks a trans-dominant pathway of tumor progression

Using a human melanoma/Scid xenograft model with the C8161, M24-met, LD-1 and other human melanoma lines to investigate spontaneous metastasis, we made the observation of marked splenomegaly (up to five times normal weight and size) in only those xenografts exhibiting high degrees of spontaneous metastasis. Evaluation of this revealed the cause to be massive myelopoiesis due to ectopic granulocyte/ colony-stimulating factor (G-CSF) production by the melanoma cells. Because of these observations linking G-CSF expression with metastasis of human melanoma, we decided to investigate the mechanism of this ectopic production. No gross amplification or rearrangement of the G-CSF gene could be detected as the basis for the increased transcriptional activity in any of these lines. Human-human somatic cell hybridization studies carried out between the metastatic C8161 and several different nonmetastatic non-G-CSF-expressing lines revealed, in addition to metastatic dominance, 3- to 10-fold enhancement of G-CSF transcription and expression in the fusions compared with C8161 itself. The suggestion of a trans-dominant mechanism was further supported by transfection studies with a human G-CSF promoter-CAT-reporter construct, which revealed 3- to 5-fold increased reporter activity in only those melanoma lines and hybrids expressing G-CSF. Furthermore, no obvious autocrine or paracrine effects of this ectopic G-CSF expression on the melanoma lines' growth or metastasis were apparent, as all of the G-CSF-expressing lines lacked the G-CSF receptor and injections of purified recombinant G-CSF exerted no stimulatory effects on their tumorigenicity, latency, growth, or metastasis in Scid mice. Thus, we advance the hypothesis that G-CSF expression is serving as a marker of a more generalized trans-dominant pathway linked to tumor progression and metastasis. This hypothesis has direct relevance to many human cancers where ectopic hormone or growth factor production occurs with no obvious autocrine or paracrine benefit to the tumor.

The myoepithelial defense: a host defense against cancer

The behavior of human tumors depends not only on the nature of the tumor cells themselves but also on the modifying effects of various normal host cells such as fibroblasts and endothelial cells. One cell type, however--the myoepithelial cell--has not been studied scientifically. Myoepithelial cells normally surround ducts and acini of glandular organs such as the breast and salivary glands and contribute to the synthesis of a surrounding basement membrane. This relationship suggests that myoepithelial cells may exert paracrine effects on glandular epithelium and also regulate the progression of ductal carcinoma in situ (DCIS) to invasive carcinoma. Myoepithelial tumors, in turn, tend to be benign or low-grade neoplasms that exhibit the rare property of accumulating rather than degrading extracellular matrix material. To better understand the nature of myoepithelial tumors, as well as the possible role of normal myoepithelial host cells in cancer, we have established immortal cell lines and a number of transplantable xenografts from various human myoepithelial tumors of the salivary gland and breast. The cell lines exhibit a normal myoepithelial phenotype and the xenografts continue to accumulate an abundant extracellular matrix. Further ultrastructural, immunocytochemical, molecular, and biochemical studies reveal that myoepithelial cells secrete relatively low levels of matrix-degrading proteinases but relatively high levels of maspin and various other anti-invasive proteinase inhibitors, that some of these inhibitors accumulate within the myoepithelial matrix, and that myoepithelial cells can induce epithelial morphogenesis (spheroid formation) and inhibit tumor-cell invasion in vitro. Myoepithelial cells, which surround normal breast ducts and DCIS, have also been found to selectively express maspin and certain proteinase inhibitors in situ. These inherent myoepithelial properties are likely to contribute to the low-grade nature of myoepithelial neoplasms and advance our hypothesis that host myoepithelial cells regulate the progression of in situ to invasive carcinoma by providing an important host defense against cancer invasion.

An update on core needle biopsy for radiologically detected breast lesions

BACKGROUND

Traditionally, radiologically detected lesions of the breast have been evaluated by open surgical biopsy with wire localization. Recently, core needle biopsy has been introduced as an alternative to open surgical biopsy. The authors evaluated their own results with long term follow-up after core needle biopsy and reviewed the experience of other physicians with this new technique.

METHODS

Four hundred thirty-one core needle biopsies performed at UCLA were analyzed. The outcome of these cases was determined by either surgery or long term follow-up. Statistical analysis was performed to determine the accuracy of the method.

RESULTS

Definitive outcome was obtained in 96% of the core needle biopsy cases, with a median follow-up time of 18 months (range, 6-38 months). The authors achieved a sensitivity of 99% and a specificity of 100%. The false-negative rate was 1.7%. There were no complications in this series.

CONCLUSIONS

Core needle biopsy is a highly accurate and safe method for the diagnosis of radiologically detected lesions of the breast.

Breast-duct endoscopy to study stages of cancerous breast disease

BACKGROUND

In breast-cancer research, we lack reproducible non-invasive access to breast tissue. Breast cancer is thought to start in the lining of the milk duct or lobule. We have had no direct access to this area other than in tissue removed surgically or by fine-needle aspiration. Our objective was to explore an intraductal approach to studying breast cancer and precancerous changes by duct cannulation and endoscopy.

METHODS

In this pilot study, women in a university hospital were asked to participate. Nine patients with previously diagnosed ductal carcinoma-in-situ (DCIS) or invasive breast cancer who were about to undergo mastectomy under general anaesthesia agreed. After the patient was asleep but before the operation, we spent 15 minutes cannulating their ducts, obtaining washings, and attempting endoscopy. The ducts that had been cannulated were marked by instillation of dye or other materials, the nipple was sutured shut, and the mastectomy proceeded as planned. The mastectomy specimen underwent extensive histopathological examination.

FINDINGS

We were successful in intraductal cannulation and endoscopy in seven of the nine patients. In five of the nine, we obtained epithelial cells in the washings. In one the cells were consistent with proliferative disease, in three there was atypical epithelium, and in one there was frank DCIS. With several different contrast materials injected into separate duct orifices, DCIS was confined to a single duct system.

INTERPRETATION

We found that the intraductal approach is feasible for the study of the early changes of breast cancer Technical difficulties include identification of the breast duct orifices, determining the distensibility of the duct, and developing a reliable technique to obtain washings.

Establishment and characterization of a novel human myoepithelial cell line and matrix-producing xenograft from a parotid basal cell adenocarcinoma

Myoepithelial cells exert important paracrine effects on epithelial morphogenesis and mitogenesis through direct cell-cell interactions and through synthesis of a basement membrane extracellular matrix. To study these effects further, this study established the first immortalized human myoepithelial cell line, HMS-1, and transplantable xenograft, HMS-X, from the rare parotid basal cell adenocarcinoma. The cell line exhibited a fully differentiated myoepithelial phenotype and the xenograft exhibited the rare property of accumulating an abundant extracellular matrix composed of both basement membrane and nonbasement membrane components with the latter predominating. With HMS-1 as a feeder layer, dramatic and specific induction of epithelial morphogenesis (spheroid formation) occurred with selected normal epithelial and primary carcinoma target cells. HMS-1 and HMS-X provide distinct advantages over the conventional murine matrices in existence. They will be invaluable in future studies of human tumor-myoepithelial and matrix interactions important for tumor cell growth, invasion, and metastasis.

Human breast cancer progression can be regulated by dominant trans-acting factors in somatic cell hybridization studies

Human breast cancer is often characterized by a progression to an ER (estrogen receptor)-negative, estrogen-independent, antiestrogen-resistant, EGFR (epidermal growth factor receptor)-positive, and highly metastatic phenotype. The molecular and biochemical mechanisms behind this progression are not well defined. Most studies of breast cancer have focused on one or another aspect or this progression but have not found a common pathway. By constructing stable and complete human-human somatic cell fusions between a highly metastatic, undifferentiated, ER-negative line of melanoma lineage and the estrogen-dependent, ER-positive MCF-7 line, this study produced hybrids that were ER negative, highly expressive of EGFR, estrogen independent, estrogen unresponsive, fully tumorigenic, and highly metastatic. ER negativity was on the basis of complete suppression of ER transcription as evidenced by Northern blot analysis and nuclear run-on assay, not on the basis of gene rearrangement. EGFR positivity was not due to gene amplification or rearrangement but rather to increased EGFR transcription. Mechanisms, including ras activation, fibroblast growth factor 4 expression, and human DNA methyltransferase activation causing ER promoter methylation, which are respectively known to induce estrogen-independent growth, induce spontaneous metastasis, and decrease ER levels in breast carcinoma experimentally, were not mechanisms operating in the hybrids. This model demonstrates that many of the common denominators of human breast carcinoma progression can be regulated by dominant trans-acting factors.

The primary tumor is the primary source of metastasis in a human melanoma/SCID model. Implications for the direct autocrine and paracrine epigenetic regulation of the metastasis process

Although previous autopsy and experimental studies had indicated that metastases can metastasize, the question of whether metastases from metastases increasingly contribute to the overall metastatic burden is crucial to the basic question of whether the metastatic process is more directly regulated by genetic or by epigenetic mechanisms. The highly metastatic human C8161 melanoma was transfected with either pSV2neo or pSV2hygro and clones of neo-C8161 and hyg-C8161 were injected intravenously and subcutaneously in SCID mice. In combination experiments, both the timing and size of inoculum of tumor cells were titrated to ensure that the hematogenously injected cells disseminated almost exclusively to the lungs and that the overall pulmonary burden was equal to the primary tumor. In s.c. injection experiments, no spontaneous metastases ever developed when the primary tumor was extirpated before it had grown to more then 0.5 cm in diameter. When the primary tumor approached 1 cm in diameter, widely-disseminated metastases developed within lungs, liver subcutaneous sites and other internal viscera. In the combination-injection experiments, while large numbers of both hematogenously and spontaneously metastatic clones were recovered from the lungs, a vast excess of only the latter clones was recovered from extrapulmonary sites. Both hematogenously and spontaneously metastatic pulmonary clones recovered showed similar levels of Matrigel invasion and collagenases by substrate gel electrophoresis, but significantly decreased levels when compared to the cell line. Primary tumor clones, in contrast, demonstrated increased invasion and increased collagenases. Our findings argue for the importance of paracrine (orthotopic) and autocrine (size) epigenetic mechanisms in the regulation of metastasis.

Characterizations of the extracellular matrix and proteinase inhibitor content of human myoepithelial tumors

Myoepithelial tumors are intriguing low-grade neoplasms that exhibit the property of accumulating an abundant extracellular matrix. Because accumulation of an extracellular matrix represents an important exception to the rule of matrix degradation otherwise exhibited by the vast majority of human epithelial neoplasms, this study investigated the composition of this matrix to gain insight into the biological behavior of this class of neoplasms. Several different human myoepithelial tumors and their derived cell lines and xenografts were thus examined by ultrastructural, immunohistochemical, molecular, and biochemical methods. Results indicated that although the extracellular matrix of these tumors contains some basement membrane components such as laminin, nidogen, and heparan sulfate proteoglycan (8%), it is also largely cartilagenous in nature, containing large amounts of chondroitin sulfate proteoglycan (78%). In addition to extracellular matrix structural proteins, myoepithelial cells secreted relatively large amounts of proteinase inhibitors including maspin, protease nexin II, alpha1-antitrypsin, a 31-kd serine proteinase inhibitor, and TIMP-1. Immunolocalization and extraction studies further demonstrated that protease nexin II and alpha1-antitrypsin especially accumulated within the myoepithelial extracellular matrix. In addition, protease nexin II likely underwent extracellular in vivo processing to a 95-kd product retaining full proteinase inhibitor activity. These specific biochemical observations unite the classes of myoepithelial tumors, confer an anti-invasive property to their extracellular matrix, and likely contribute to their low-grade biological behavior.