A collection of breast cancer cell lines for the study of functionally distinct cancer subtypes.

Recent studies suggest that thousands of genes may contribute to breast cancer pathophysiologies when deregulated by genomic or epigenomic events. Here, we describe a model "system" to appraise the functional contributions of these genes to breast cancer subsets. In general, the recurrent genomic and transcriptional characteristics of 51 breast cancer cell lines mirror those of 145 primary breast tumors, although some significant differences are documented. The cell lines that comprise the system also exhibit the substantial genomic, transcriptional, and biological heterogeneity found in primary tumors. We show, using Trastuzumab (Herceptin) monotherapy as an example, that the system can be used to identify molecular features that predict or indicate response to targeted therapies or other physiological perturbations.

Calmodulin modulates Akt activity in human breast cancer cell lines.

Growth factor-induced activation of Akt occurs in the majority of human breast cancer cell lines resulting in a variety of cellular outcomes, including suppression of apoptosis and enhanced survival. We demonstrate that epidermal growth factor (EGF)-initiated activation of Akt is mediated by the ubiquitous calcium sensing molecule, calmodulin, in the majority of human breast cancer cell lines. Specifically, in estrogen receptor (ER)-negative, but not ER-positive, breast cancer cells, Akt activation is abolished by treatment with the calmodulin antagonist, W-7. Suppression of calmodulin expression by siRNAs against all three calmodulin genes in c-Myc-overexpressing mouse mammary carcinoma cells results in significant inhibition of EGF-induced Akt activation. Additionally, transient expression of constitutively active Akt (Myr-Akt) can overcome W-7-mediated suppression of Akt activation. These results confirm the involvement of calmodulin in the Akt pathway. The calmodulin independence of EGF-initiated Akt signaling in some cells was not explained by calmodulin expression level. Additionally, it was not explained by ER status or activation, since removal of estrogen and ablation of the ER did not convert the ER-positive, W-7 insensitive, MCF-7 cell line to calmodulin dependent signaling. However, forced overexpression of either epidermal growth factor receptor (EGFR) or ErbB2 did partially restore calmodulin dependent EGF-stimulated Akt activation. This is consistent with observation that W-7 sensitive cells tend to be estrogen independent and express high levels of EGFR family members. In an attempt to address how calmodulin is regulating Akt activity, we looked at localization of fluorescently tagged Akt and calmodulin in MCF-7 and SK-BR-3 cells. We found that both Akt and calmodulin translocate to the membrane after EGF-stimulation, and this translocation to the same sub-cellular compartment is inhibited by the calmodulin inhibitor W-7. Thus, calmodulin may be regulating Akt activity by modulating its sub-cellular location and is a novel target in the poor prognosis, ER-negative subset of breast cancers.

Prognostic relevance of c-MYC gene amplification and polysomy for chromosome 8 in suboptimally-resected, advanced stage epithelial ovarian cancers: a Gynecologic Oncology Group study.

OBJECTIVE: The Gynecologic Oncology Group (GOG) examined the prognostic relevance of c-MYC amplification and polysomy 8 in epithelial ovarian cancer (EOC). METHODS: Women with suboptimally-resected, advanced stage EOC who participated in GOG-111, a multicenter randomized phase III trial of cyclophosphamide+cisplatin vs. paclitaxel+cisplatin, and who provided a tumor block through GOG-9404 were eligible. Fluorescence in situ hybridization (FISH) with probes for c-MYC and the centromere of chromosome 8 (CEP8) was used to examine c-MYC amplification (> or =2 copies c-MYC/CEP8) and polysomy 8 (> or =4 CEP8 copies). RESULTS: c-MYC amplification, defined as > or =2 copies c-MYC/CEP8, was observed in 29% (28/97) of EOCs and levels were ranged from 2.0-3.3 copies of c-MYC/CEP8. c-MYC amplification was not associated with patient age, race, GOG performance status, stage, cell type, grade, measurable disease status following surgery, tumor response or disease status following platinum-based combination chemotherapy. Women with vs. without c-MYC amplification did not have an increased risk of disease progression (hazard ratio [HR]=1.03; 95% confidence interval [CI]=0.65-1.64; p=0.884) or death (HR=1.08; 95% CI=0.68-1.72; p=0.745). c-MYC amplification was not an independent prognostic factor for progression-free survival (HR=1.03, 95% CI=0.57-1.85; p=0.922) or overall survival (HR=1.01, 95% CI=0.56-1.80; p=0.982). Similar insignificant results were obtained for c-MYC amplification categorized as > or =1.5 copies c-MYC/CEP8. Polysomy 8 was observed in 22 patients without c-MYC amplification and 3 with c-MYC amplification, and was associated with age and measurable disease status, but not other clinical covariates or outcomes. CONCLUSIONS: c-MYC amplification and polysomy 8 have limited predictive or prognostic value in suboptimally-resected, advanced stage EOC treated with platinum-based combination chemotherapy.

Zymogen activation, inhibition, and ectodomain shedding of matriptase.

Matriptase is a member of an expanding group of type II transmembrane serine proteases. Recently, much has been learned about the biochemistry, cellular biology, normal tissue physiology, and human pathology of this protease, and of its inhibitor, termed the hepatocyte growth factor inhibitor-1 (HAI-1). This review examines the recent literature that has characterized the regulation of matriptase and HAI-1 with an emphasis on the molecular mechanisms governing its zymogen activation, inhibition by HAI-1, and ectodomain shedding.

Design and synthesis of novel and potent inhibitors of the type II transmembrane serine protease, matriptase, based upon the sunflower trypsin inhibitor-1.

Matriptase, initially isolated from human breast cancer cells in culture, is a member of the emerging class of type II transmembrane serine proteases. Matriptase blockade could potentially modulate tumorigenesis and metastasis in vivo. Sunflower trypsin inhibitor-1 (1, SFTI-1), isolated from sunflower seeds, exhibits very potent matriptase inhibitory activity. On the basis of these findings, we designed and synthesized 13 analogues of the naturally occurring peptide 1 with the intention to explore the structure-activity relationships of this type of bicyclic peptides and to improve inhibitory selectivity and metabolic stability of the disulfide-bridge-containing peptide 1. We discovered that the methylenedithioether-bridged compound 14 demonstrates very potent binding affinity to matriptase. Compound 8 exhibits much better selectivity for inhibition of matriptase versus thrombin, whereas compound 2 becomes a more potent thrombin inhibitor, which can be potentially used as an anticoagulant for prophylaxis and therapy of thromboembolism.

Design and synthesis of redox stable analogues of sunflower trypsin inhibitors (SFTI-1) on solid support, potent inhibitors of matriptase.

[structure: see text] Matriptase is a member of the emerging class of type II transmembrane serine proteases. It was found that the sunflower trypsin inhibitor (SFTI-1), isolated from sunflower seeds, inhibits matriptase with a subnanomolar Ki of 0.92 nM. On the basis of this result, we designed and synthesized its proteolytically stable analogues, SFTI-2 and SFTI-3. SFTI-3 exhibited very good binding affinity to matriptase, and it was metabolically stable.

Overexpression of c-Myc alters G(1)/S arrest following ionizing radiation.

Study of the mechanism(s) of genomic instability induced by the c-myc proto-oncogene has the potential to shed new light on its well-known oncogenic activity. However, an underlying mechanism(s) for this phenotype is largely unknown. In the present study, we investigated the effects of c-Myc overexpression on the DNA damage-induced G(1)/S checkpoint, in order to obtain mechanistic insights into how deregulated c-Myc destabilizes the cellular genome. The DNA damage-induced checkpoints are among the primary safeguard mechanisms for genomic stability, and alterations of cell cycle checkpoints are known to be crucial for certain types of genomic instability, such as gene amplification. The effects of c-Myc overexpression were studied in human mammary epithelial cells (HMEC) as one approach to understanding the c-Myc-induced genomic instability in the context of mammary tumorigenesis. Initially, flow-cytometric analyses were used with two c-Myc-overexpressing, nontransformed immortal lines (184A1N4 and MCF10A) to determine whether c-Myc overexpression leads to alteration of cell cycle arrest following ionizing radiation (IR). Inappropriate entry into S phase was then confirmed with a bromodeoxyuridine incorporation assay measuring de novo DNA synthesis following IR. Direct involvement of c-Myc overexpression in alteration of the G(1)/S checkpoint was then confirmed by utilizing the MycER construct, a regulatable c-Myc. A transient excess of c-Myc activity, provided by the activated MycER, was similarly able to induce the inappropriate de novo DNA synthesis following IR. Significantly, the transient expression of full-length c-Myc in normal mortal HMECs also facilitated entry into S phase and the inappropriate de novo DNA synthesis following IR. Furthermore, irradiated, c-Myc-infected, normal HMECs developed a sub-G(1) population and a >4N population of cells. The c-Myc-induced alteration of the G(1)/S checkpoint was also compared to the effects of expression of MycS (N-terminally truncated c-Myc) and p53DD (a dominant negative p53) in the HMECs. We observed inappropriate hyperphosphorylation of retinoblastoma protein and then the reappearance of cyclin A, following IR, selectively in full-length c-Myc- and p53DD-overexpressing MCF10A cells. Based on these results, we propose that c-Myc attenuates a safeguard mechanism for genomic stability; this property may contribute to c-Myc-induced genomic instability and to the potent oncogenic activity of c-Myc.

A novel biomarker for staging human prostate adenocarcinoma: overexpression of matriptase with concomitant loss of its inhibitor, hepatocyte growth factor activator inhibitor-1.

BACKGROUND: Matriptase, a type II transmembrane serine protease is involved in angiogenesis, degradation of extracellular matrix, and in the progression of some epithelial cancers. Here, we establish the clinical significance of matriptase and its inhibitor, hepatocyte growth factor activator inhibitor-1 (HAI-1), during the progression of human prostate cancer (CaP). METHODS: The expression patterns of matriptase and HAI-1 were determined in primary cultures of normal human prostate epithelial (NHPE) cells, human CaP cells LNCaP, DU-145, CWR22Rnu1, and PC-3, and in tissue samples of 172 patients with normal prostate, benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), and adenocarcinoma of different tumor grades. RESULTS: The protein and mRNA levels of matriptase were significantly higher in all carcinoma cells as compared with NHPE cells. Conversely, all CaP cells exhibited a reduced expression of HAI-1 as compared with NHPE cells. A progressive increase in the protein levels of matriptase was observed with increasing tumor grade in CaP specimens as compared with normal and BPH tissue specimens. Tissue samples of normal prostate exhibited a high constitutive protein level of HAI-1 compared with BPH and low-grade cancer with a progressive loss with increasing tumor grade. CONCLUSION: The increased expression of matriptase and loss of HAI-1 may be an important event during the progression of CaP in humans. We suggest that the ratio of these two gene products may serve as a promising biomarker for CaP progression and a potential marker for establishing the efficacy of therapeutic and chemopreventive interventions.

Identification of membrane-bound serine proteinase matriptase as processing enzyme of insulin-like growth factor binding protein-related protein-1 (IGFBP-rP1/angiomodulin/mac25).

Insulin-like growth factor (IGF) binding protein-related protein-1 (IGFBP-rP1) modulates cellular adhesion and growth in an IGF/insulin-dependent or independent manner. It also shows tumor-suppressive activity in vivo. We recently found that a single-chain IGFB-rP1 is proteolytically cleaved to a two-chain form by a trypsin-like, endogenous serine proteinase, changing its biological activities. In this study, we attempted to identify the IGFBP-rP1-processing enzyme. Of nine human cell lines tested, seven cell lines secreted IGFBP-rP1 at high levels, and two of them, ovarian clear cell adenocarcinoma (OVISE) and gastric carcinoma (MKN-45), highly produced the cleaved IGFBP-rP1. Serine proteinase inhibitors effectively blocked the IGFBP-rP1 cleavage in the OVISE cell culture. The conditioned medium of OVISE cells did not cleave purified IGFBP-rP1, but their membrane fraction had an IGFBP-rP1-cleaving activity. The membrane fraction contained an 80-kDa gelatinolytic enzyme, which was identified as the membrane-type serine proteinase matriptase (MT-SP1) by immunoblotting. When the membrane fraction was separated by SDS/PAGE, the IGFBP-rP1-cleaving activity comigrated with matriptase. A soluble form of matriptase purified in an inhibitor-free form efficiently cleaved IGFBP-rP1 at the same site as that found in a naturally cleaved IGFBP-rP1. Furthermore, small interfering RNAs for matriptase efficiently blocked both the matriptase expression and the cleavage of IGBP-rP1 in OVISE cells. These results demonstrate that IGFBP-rP1 is processed to the two-chain form by matriptase on the cell surface.

Fluorescence in situ hybridization assessment of c-myc gene amplification in breast tumor tissues.

This chapter details methods used for analysis of DNA copy-number changes in breast tumor tissues through the use of fluorescence in situ hybridization. The specific DNA probe described herein is the oncogene c-myc, although the tissue fluorescence in situ hybridization methodology presented is suitable for dual-color studies of most unique sequence and chromosome specific control probes. The breast tumor tissue sections are first deparaffinized in a solvent and clearing agent, and then pretreated with a protease to allow the target DNA within the breast tissue cells to be uncovered. This allows the DNA to be available for hybridization with the labeled c-myc probe. The tissue sections are then analyzed to assure that appropriate digestion of cellular material has been attained. The tissues are then denatured. The c-myc probe and control probe for the centromere of chromosome 8 are commercially available as differentially labeled and are cohybridized to the tissue and sealed beneath a cover slip in a humid chamber. They are incubated for 12-16 h. The cover slip is then removed, and the section is postwashed in 2X saline sodium citrate at 72 degrees C for 5 min and allowed to cool to room temperature in a detergent solution. The slides are then counterstained with 4',6-diamidino-2-phenylindole, and a cover slip is applied. The slides are then viewed with fluorescence microscopy using filters that allow the c-myc and chromosome 8 signals to be visualized. If possible, 50 cells are counted, and the data are expressed as number of c-myc signals/number of chromosome 8 signals.

Tissue microarray analysis of hepatocyte growth factor/Met pathway components reveals a role for Met, matriptase, and hepatocyte growth factor activator inhibitor 1 in the progression of node-negative breast cancer.

Numerous studies have demonstrated that overexpression of Met, the hepatocyte growth factor(HGF) receptor, plays an important role in tumorigenesis. Met activation can either occur through ligand-independent or -dependent mechanisms, both of which are mediated by a series of proteases and modulators. We studied the protein expression of several components of the HGF/Met pathway on a cohort of 330 node-negative breast carcinomas using a tissue microarray annotated with 30-year, disease-specific patient follow-up data. We examined HGF, matriptase (an activator of HGF expressed on mammary epithelial cell surfaces), HAI-I (the cognate inhibitor of matriptase), and the Met receptor itself. Our studies demonstrate tight correlation between the expression of HGF, matriptase, and Met in breast carcinoma. High-level expression of Met, matriptase, and HAI-I were associated with poor patient outcome. Met and HAI-I showed independent prognostic value when compared with traditional breast markers in a multivariate analysis. Intriguingly, antibodies against the intracellular but not the extracellular domain of Met were prognostic, suggesting that overexpression of the cytoplasmic-tail of Met, perhaps through cleavage or truncating mutation, may play an important role in breast cancer progression.

Pentameric procyanidin from Theobroma cacao selectively inhibits growth of human breast cancer cells.

A naturally occurring, cocoa-derived pentameric procyanidin (pentamer) was previously shown to cause G0/G1 cell cycle arrest in human breast cancer cells by an unknown molecular mechanism. Here, we show that pentamer selectively inhibits the proliferation of human breast cancer cells (MDA MB-231, MDA MB-436, MDA MB-468, SKBR-3, and MCF-7) and benzo(a)pyrene-immortalized 184A1N4 and 184B5 cells. In contrast, normal human mammary epithelial cells in primary culture and spontaneously immortalized MCF-10A cells were significantly resistant. We evaluated whether this differential response to pentamer may involve depolarization of the mitochondrial membrane. Pentamer caused significant depolarization of mitochondrial membrane in MDA MB231 cells but not the more normal MCF-10A cells, whereas other normal and tumor cell lines tested gave variable results. Further investigations, using a proteomics approach with pentamer-treated MDA MB-231, revealed a specific dephosphorylation, without changes in protein expression, of several G1-modulatory proteins: Cdc2 (at Tyr15), forkhead transcription factor (at Ser256, the Akt phosphorylation site) and p53 (Ser392). Dephosphorylation of p53 (at Ser392) by pentamer was confirmed in MDA MB-468 cells. However, both expression and phosphorylation of retinoblastoma protein were decreased after pentamer treatment. Our results show that breast cancer cells are selectively susceptible to the cytotoxic effects of pentameric procyanidin, and suggest that inhibition of cellular proliferation by this compound is associated with the site-specific dephosphorylation or down-regulation of several cell cycle regulatory proteins.

Coexpression of beta1,6-N-acetylglucosaminyltransferase V glycoprotein substrates defines aggressive breast cancers with poor outcome.

Beta1,6-n-acetylglucosaminyltransferase-V (GnT-V) catalyzes the addition of complex oligosaccharide side chains to glycoproteins, regulating the expression and function of several proteins involved in tumor metastasis. We analyzed the expression of five cell-surface glycoprotein substrates of GnT-V, matriptase, beta1-integrin, epidermal growth factor receptor, lamp-1, and N-cadherin, on a tissue microarray cohort of 670 breast carcinomas with 30-year follow-up. Phaseolus vulgaris leukocytic phytohemagglutinin (LPHA), a lectin specific for beta1,6-branched oligosaccharides, was used to assay GnT-V activity. Our results show a high degree of correlation of the LPHA staining with matriptase, lamp-1, and N-cadherin expressions, but not with epidermal growth factor receptor or beta1-integrin expressions. In addition, many of the GnT-V substrate proteins exhibited strong coassociations. Elevated levels of GnT-V substrates were correlated with various markers of tumor progression, including positive node status, large tumor size, estrogen receptor negativity, HER2/neu overexpression, and high nuclear grade. Furthermore, LPHA and matriptase showed significant association with disease-related survival. Unsupervised hierarchical clustering of the GnT-V substrate protein expression and LPHA revealed two distinct clusters: one with higher expression of all markers and poor patient outcome and one with lower expression and good outcome. These clusters showed independent prognostic value for disease-related survival when compared with traditional markers of tumor progression. Our results indicate that GnT-V substrate proteins represent a unique subset of coexpressed tumor markers associated with aggressive disease.

Increased expression of matriptase is associated with histopathologic grades of cervical neoplasia.

Matriptase is an epithelial-derived, integral serine protease that has been implicated in the progression of epithelial tumors. We investigated whether the expression of matriptase is associated with the progression of cervical neoplasia. Using immunohistochemistry, we evaluated the matriptase expression in 89 formalin-fixed paraffin-embedded cervical tissues that included 10 normal cervical specimens, 19 low-grade squamous intraepithelial lesions, 20 high-grade squamous intraepithelial lesions, 20 invasive squamous cell carcinomas (ISCC) without lymph node (LN) metastasis, and 20 ISCC with lymph node metastasis. We also used the reverse transcriptase-polymerase chain reaction technique to determine the expression of matriptase transcripts in normal cervical and ISCC tissues. The immunohistochemical staining showed that the expression of matriptase was undetectable in all normal cervical squamous epithelia, but had cytoplasmic and membranous staining in the normal endocervical glands. Staining gradually increased in accordance with the histopathologic grades from low-grade squamous intraepithelial lesions to high-grade squamous intraepithelial lesions and ISCC ( P < .001); matriptase was detected in most cases (95%) of ISCC. In addition, matriptase transcripts were expressed in all (n = 26) of the ISCC cases by microdissection and reverse transcriptase-polymerase chain reaction, whereas none of the normal squamous epithelia cases (n = 3) expressed matriptase transcripts. These results suggest that matriptase may play a significant role in the development of cervical carcinoma and may serve as a useful marker of the malignant transformation of cervical squamous cells. Further studies could potentially lead to the development of novel approaches for early detection and therapy for this disease.

Expression of the serine protease matriptase and its inhibitor HAI-1 in epithelial ovarian cancer: correlation with clinical outcome and tumor clinicopathological parameters.

PURPOSE: Matriptase is a type II transmembrane serine protease expressed by cells of surface epithelial origin, including epithelial ovarian tumor cells. Matriptase cleaves and activates proteins implicated in the progression of ovarian cancer and represents a potential prognostic and therapeutic target. The aim of this study was to examine the expression of matriptase, and its inhibitor, hepatocyte growth factor activator inhibitor-1 (HAI-1), in epithelial ovarian cancer and to assign clinicopathological correlations. EXPERIMENTAL DESIGN: We have determined by immunohistochemistry the expression of matriptase and HAI-1 in 54 epithelial ovarian cancers. Statistical analyses of immunohistochemistry expression data with clinical outcome and clinicopathological parameters were then performed. RESULTS: Of 54 tumors tested, 39 (72%) and 11 (20%) were positive for matriptase and for HAI-1, respectively. All HAI-1-positive tumors were also matriptase positive. Analysis of clinicopathological parameters demonstrated a loss of matriptase associated with stage III/IV tumors as compared with stage I/II tumors (P = 0.030). There was also a loss of HAI-1 expression associated with stage III/IV tumors (P = 0.039). Of 34 stage I/II tumors, 28 (82%) stained positive for matriptase, and 10 (29%) stained positive for HAI-1; 10 (29%) tumors showed coexpression. Of 20 stage III/IV tumors, however, 11 stained positive for matriptase (55%), only 1 of which coexpressed HAI-1 (P = 0.039). CONCLUSIONS: Advanced-stage ovarian tumors that express matriptase are more likely to do so in the absence of its inhibitor, HAI-1, indicating that an imbalance in the matriptase:HAI-1 ratio could be important in the development of advanced disease. Such an imbalance could promote the proteolytic activity of matriptase and, consequently, a more invasive phenotype.

Deregulated activation of matriptase in breast cancer cells.

Matriptase is an epithelial-derived, cell surface serine protease. This protease activates hepatocyte growth factor (HGF) and urokinase plasminogen activator (uPA), two proteins thought to be involved in the growth and motility of cancer cells, particularly carcinomas, and in the vascularization of tumors. Thus, matriptase may play an important role in the progression of carcinomas, such as breast cancer. We examined the regulation of activation of matriptase in human breast cancer cells, in comparison to non-transformed mammary epithelial cells 184A1N4 and MCF-10A. Results clearly indicated that unlike non-transformed mammary epithelial cells, breast cancer cells do not respond to the known activators of matriptase, serum and sphingosine 1-phosphate (S1P). Similar levels of activated matriptase were detected in breast cancer cells, grown in the presence or absence of S1P. However, up to five-fold higher levels of activated matriptase were detected in the conditioned media from the cancer cells grown in the absence of serum and S1P, when compared to non-transformed mammary epithelial cells. S1P also induces formation of cortical actin structures in non-transformed cells, but not in breast cancer cells. These results show that in non-transformed cells, S1P induces a rearrangement of the actin cytoskeleton and stimulates proteolytic activity on cell surfaces. In contrast, S1P treatment of breast cancer cells does not activate matriptase, and instead these cells constitutively activate the protease. In addition, breast cancer cells respond differently to S1P in terms of the regulation of actin cytoskeletal structures. Matriptase and its cognate inhibitor, HGF activator inhibitor 1 (HAI-1) colocalize on the cell periphery of breast cancer cells and form stable complexes in the extracellular milieu, suggesting that the inhibitor serves to prevent undesired proteolysis in these cells. Finally, we demonstrate that treatment of T-47D cells with epidermal growth factor (EGF), which promotes cell ruffling, stimulates increased accumulation of activated matriptase at the sites of membrane ruffling, suggesting a possible functional role at these sites.

Characterization of matriptase expression in normal human tissues.

Matriptase is a type II transmembrane serine protease that has been implicated in the progression of epithelium-derived tumors. The role of this protease in the biology of normal epithelial cells remains to be elucidated. Matriptase mRNA has been detected by Northern analysis in tissues rich in epithelial cells, and the protein is expressed in vivo in normal and cancerous breast, ovarian, and colon tissues. However, a systematic analysis of the distribution of matriptase protein and mRNA in normal human tissues rich in epithelium has not been reported. In this study we characterized the expression of the protease in a wide variety of normal human tissues using a tissue microarray and whole tissue specimens. Significant immunoreactivity and mRNA expression were detected in the epithelial components of most epithelium-containing tissues. Matriptase expression was found in all types of epithelium, including columnar, pseudostratified columnar, cuboidal, and squamous. Distinct spatial distributions of reactivity were observed in the microanatomy of certain tissues, however. This suggests that although matriptase is broadly expressed among many types of epithelial cells, its activity within a tissue may be regulated in part at the protein and mRNA levels during the differentiation of selected epithelia.

Type II transmembrane serine proteases.

The recent availability of human and mouse genome sequences and expressed sequence tag databases facilitated the identification of a large new family of membrane anchored serine proteases, the type II transmembrane serine proteases or TTSPs. Analyses of human inherited disorders and gene targeting studies in mice have revealed that several members of this new protease family have critical functions in development and health. Preliminary studies also suggest that aberrant expression of type II transmembrane serine proteases may be linked to disease progression. The knowledge gathered thus far of the genetics, physiology, and pathology of this interesting new serine protease family will be reviewed here in brief.

Possible role of matriptase in the diagnosis of ovarian cancer.

There are increasing data that suggest a role for the serine protease matriptase and its inhibitor, hepatocyte growth factor activator inhibitor-1, in the pathogenesis and progression of ovarian cancer. This review will discuss the matriptase/inhibitor system in the context of ovarian cancer and examine the possibility that this system might be a useful therapeutic and/or diagnostic target in this disease.

Roles of androgens in the development, growth, and carcinogenesis of the mammary gland.

Androgens influence the development and growth of the mammary gland in women. Treatment of animals and cultured cells with androgens has either inhibitory or stimulatory effects on the proliferation of mammary epithelia and cancer cells; the mechanisms for these dual functions are still not very clear and are discussed in this review. Epidemiological data suggest that, similar to increased estrogens, elevated androgens in serum may be associated with the development of breast cancer. Experiments in rodents have also shown that simultaneous treatment of androgen and estrogen synergizes for mammary gland carcinogenesis. Similar synergistic effects of both hormones have been observed for carcinogenesis of the uterine myometrium of female animals and for carcinogenesis of the prostate and deferens of males. There are also clinical and experimental indications for a possible association of elevated levels of both androgens and estrogens with the development of ovarian and endometrial cancers. A hypothesis is thus proposed that concomitant elevation in both androgens and estrogens may confer a greater risk for tumorigenesis of the mammary gland, and probably other female reproductive tissues than an elevation of each hormone alone.