Abstract P2-02-14: Metabolic regulation and drug resistance in c-Src activated triple negative breast cancer

c-Src (Src) is a proto-oncogene involved in signaling that culminates in the control of multiple biological functions. Src is also one of the most frequently upregulated pathways in triple negative breast cancer (TNBC). Dysregulation of Src has been detected in TNBC and is strongly associated with tumor metastasis and poor prognosis. However, even after promising preclinical studies, Src inhibitors did not show major clinical advantage in unselected TNBC populations. We have previously published that metastatic TNBC has high energy-dependency to mitochondrial fatty acid beta-oxidation (FAO) and FAO activates Src by inducing autophosphorylation at Y419. However, our recent analysis suggests that as observed with the Src inhibitors, TNBC tumors treated with FAO inhibitors also develop drug-resistance and continue tumor growth. Evaluation of their drug resistance mechanism revealed that while short-term inhibition of FAO or Src induces autophagic and apoptotic cell deaths, long-term inhibition results in autophagy-mediated drug resistance and survival. Further analyses suggest that FAO and Src inhibitors activate mitogen-activated protein (MAP) kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway via the induction of cellular reactive oxygen species (ROS) in TNBC. Activated MEK/ERK then induces survival pathways for drug resistance and tumor survival. Validation of in vitro findings using in vivo TNBC models confirmed that combination of FAO/Src inhibitors with MEK/ERK inhibitors can provide significant benefit to overcome the therapeutic resistance of TNBC. These findings open-up new therapeutic opportunities to manage TNBC patients with currently non-targetable metastatic tumors.

Citation Format: Jung KH, Park JH, Sirupangi T, Jia D, Gandhi N, Pudakalakatti S, Elswood J, Porter W, Putluri N, Zhang XH-F, Chen X, Bhattacharya PK, Creighton CJ, Lewis MT, Rosen JM, Wong L-JC, Das GM, Osborne CK, Rimawi MF, Kaipparettu BA. Metabolic regulation and drug resistance in c-Src activated triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-02-14.

GD3 synthase regulates epithelial-mesenchymal transition and metastasis in breast cancer

The epithelial-mesenchymal transition (EMT) bestows cancer cells with increased stem cell properties and metastatic potential. To date, multiple extracellular stimuli and transcription factors have been shown to regulate EMT. Many of them are not druggable and therefore it is necessary to identify targets, which can be inhibited using small molecules to prevent metastasis. Recently, we identified the ganglioside GD2 as a novel breast cancer stem cell marker. Moreover, we found that GD3 synthase (GD3S)--an enzyme involved in GD2 biosynthesis--is critical for GD2 production and could serve as a potential druggable target for inhibiting tumor initiation and metastasis. Indeed, there is a small molecule known as triptolide that has been shown to inhibit GD3S function. Accordingly, in this manuscript, we demonstrate that the inhibition of GD3S using small hairpin RNA or triptolide compromises the initiation and maintenance of EMT instigated by various signaling pathways, including Snail, Twist and transforming growth factor-β1 as well as the mesenchymal characteristics of claudin-low breast cancer cell lines (SUM159 and MDA-MB-231). Moreover, GD3S is necessary for wound healing, migration, invasion and stem cell properties in vitro. Most importantly, inhibition of GD3S in vivo prevents metastasis in experimental as well as in spontaneous syngeneic wild-type mouse models. We also demonstrate that the transcription factor FOXC2, a central downstream effector of several EMT pathways, directly regulates GD3S expression by binding to its promoter. In clinical specimens, the expression of GD3S correlates with poor prognosis in triple-negative human breast tumors. Moreover, GD3S expression correlates with activation of the c-Met signaling pathway leading to increased stem cell properties and metastatic competence. Collectively, these findings suggest that the GD3S-c-Met axis could serve as an effective target for the treatment of metastatic breast cancers.

Primary cutaneous amyloidosis of the glans penis. Two case reports and a review of the literature

BACKGROUND

Primary cutaneous amyloidosis of the penis is a rare entity.

OBJECTIVES

We describe two cases of primary penile cutaneous amyloidosis presenting as localized lesions on the penis and not associated with systemic amyloidosis.

METHODS

A comprehensive literature review of all published cases.

RESULTS

The rarest form of cutaneous amyloidosis, nodular amyloidosis, is the most frequent presentation of penis-limited cutaneous amyloid with a low incidence of systemic disease progression.

CONCLUSIONS

Although primary nodular amyloidosis is a rare entity it seems to be the most frequent presentation of penile-limited cutaneous disease, with a low incidence of systemic involvement.

Determinants of the variability of aflatoxin-albumin adduct levels in Ghanaians

Hepatocellular carcinoma (HCC) is a multifactorial disease with various host and environmental factors involved in its etiology. Of these, aflatoxin exposure has been established as an important risk factor in the development of HCC; the presence of aflatoxin-albumin (AA) adducts in the blood serves as a valuable biomarker of human exposure. In this study, the relationship between a variety of different HCC host factors and the incidence of AA adduct levels was examined in a Ghanaian population at high risk for HCC. These factors included age, gender, hepatitis virus B (HVB) and hepatitis C virus (HCV) status, and genetic polymorphisms in both microsomal epoxide hydrolase (mEH) and glutathione S-transferases (GSTs). Blood samples were analyzed for AA adducts and HBV and HCV status. GSTM1 and GSTT1 deletion polymorphisms and mEH exon 3 and exon 4 single-nucleotide polymorphisms (SNPs) were determined from urine samples. In univariate analysis, age, HBV and HVC status, and GSTT1 and mEH exon 3 genotypes were not associated with AA adduct levels. However, mean adduct levels were significantly higher in both females and individuals typed heterozygous for mEH exon 4 (vs. wild types). Stratification analysis also showed that gender along with mEH exon 4 genotype and HBV status had a significant effect on adduct levels. Both females typed HBsAg+ and males with mEH exon 4 heterozygote genotypes showed significantly higher adduct levels as compared to the HBsAg- and wild types, respectively. Understanding the relationships between these host factors and the variability in aflatoxin-adduct levels may help in identifying susceptible populations in developing countries and for targeting specific public health interventions for the prevention of aflatoxicoses in populations with HCC and chronic liver diseases.

Noninvasive identification of interindividual variation in xenobiotic-metabolizing enzymes: implications for cancer epidemiology and biomarker studies

In this study, DNA extracted from frozen urine was used in the analysis of polymorphisms in genes coding for xenobiotic-metabolizing enzymes (XMEs). These included single-nucleotide polymorphisms (SNP) in microsomal epoxide hydrolase (mEH), that is, substitutions of tyrosine by histidine in codon 113 (Y113H) and histidine by arginine in codon 139 (H139R), and deletion polymorphisms in glutathione S-transferase (GST) M1 and T1 genes. The concentration of DNA extracted from urine of a Ghanaian population (n = 91) exposed to aflatoxins in their diet ranged from 82.5 to 573 ng/ml urine. Polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) procedures were used for the characterization of mEH polymorphisms, whereas a multiplex PCR method was utilized to identify GST deletion polymorphisms. In total, 91% and 94% of 91 samples were genotyped for mEH exon 3 and exon 4 polymorphisms, respectively. In the multiplex analysis of GST polymorphisms, 94% and 91% of 91 individuals were genotyped for GSTM1 and GSTT1 polymorphisms, respectively. The polymorphisms in the mEH exon 4, GSTM1 and GSTT1, were not in Hardy-Weinberg equilibrium (HWE) except for mEH exon 3. Representative genotypes identified by PCR-RFLP were cloned and sequenced, then confirmed by comparison with reference sequences of human DNA published in the GenBank BLAST database. These results demonstrate that XMEs can be genotyped from urine with reliable accuracy and may be useful in cancer and molecular epidemiology studies.

Treatment of toxic epidermal necrolysis with intravenous immunoglobulin

Toxic epidermal necrolysis (TEN) is a rare severe reaction of the skin resulting in full thickness damage to the epidermis. The condition has significant morbidity as a result of dehydration, protein loss, thermoregulatory difficulties, and renal, lung, liver and heart failure. The mortality rate approaches 30%, most commonly from bacterial sepsis. Management of this condition is cessation of the suspected causative agent and supportive care on a burns or intensive care unit. There have been recent reports of treatment using intravenous immunoglobulin (IVIG) therapy, though its efficacy is yet to be established. It has been proposed that IVIG inhibits the Fas-FasL mediated apoptosis of keratinocytes affected by TEN. We describe a case of extensive drug-induced TEN in a 33-year-old woman who showed rapid improvement with IVIG therapy at a dose of 0.75 g/kg/day given for four consecutive days.

Stronger proliferative response to membrane versus cell-wall Streptococcal proteins by peripheral blood T cells in chronic plaque psoriasis

Proliferative responses of peripheral blood mononuclear cells (PBMC) to group A streptococcal (GAS) antigens have been studied in 24 patients with psoriasis and 15 disease controls. Extracts of cell wall (including M protein) from types M4 and M12 GAS, recombinant M6 protein, and both cell-wall and cell-membrane extracts from type M6 (M6+) GAS and its corresponding M gene deletion mutant (M6-) were tested. PBMC from psoriatic patients proliferated more strongly to cell-wall extracts from M12 versus M4 (P = 0.0348), and to M6+ versus M6- (P = 0.0019) GAS with, in most cases, moderate proliferation to recombinant M6 protein. The psoriatic response to M12 cell wall was significantly increased compared to the controls (P = 0.0032). In psoriatics, M6+ membrane extracts induced a markedly greater proliferation than those of cell wall (P = 0.0002); responses to M6+ (P = 0.0039) and M6- (P = 0.0114) membrane extracts were higher than those of the control PBMC. Both groups showed a decreased response to the M6- versus M6+ membrane extracts (P = 0.0030; P = 0.0181, respectively). This study has demonstrated that patients with psoriasis have a heightened circulating T-cell response to cell wall M protein and to non-M proteins present on the cell wall and membrane of GAS.

Skin T cell proliferative response to M protein and other cell wall and membrane proteins of group A streptococci in chronic plaque psoriasis

To determine and compare the T cell response to M protein and other group A streptococcal (GAS) antigens, T cell lines (TCL) were cultured from the lesional skin of 33 psoriatic patients and 17 disease controls. GAS-reactive skin TCL were tested in proliferation assays with recombinant M6 protein, and extracts of cell wall and membrane from type M6 GAS and its corresponding M gene deletion mutant. Initially, GAS-reactive skin TCL were obtained from 16 of 25 (64%) psoriasis, and from seven of 17 (41%) control patients. Eleven psoriatic and four control GAS-reactive TCL proliferated to M6 cell wall extract, whereas all the TCL from both groups responded to the extract of M6 membrane proteins. This difference in response to the two extracts was significant for both groups of patients (psoriasis, P = 0.0335, controls, P = 0.0156). GAS-reactive TCL from a further eight psoriasis patients showed no difference in response to cell wall extract from M6 GAS (containing the M protein minus its C-terminus) compared to that of its corresponding M gene deletion mutant. Furthermore, GAS-reactive TCL did not proliferate to recombinant M6 protein. However, a small, but significant reduction in proliferation by the eight psoriatic GAS-reactive TCL to the M-negative (lacking the M protein C-terminus) compared to M6-positive membrane extract was observed (P = 0.01). These findings suggest that GAS-reactive T cells in skin lesions of chronic plaque psoriasis proliferate to streptococcal membrane and, to a lesser extent, cell wall proteins. However, psoriatic skin T cells do not recognize cell wall M protein.

Ritonavir: an extraordinary example of conformational polymorphism

PURPOSE

In the summer of 1998, Norvir semi-solid capsules supplies were threatened as a result of a new much less soluble crystal form of ritonavir. This report provides characterization of the two polymorphs and the structures and hydrogen bonding network for each form.

METHODS

Ritonavir polymorphism was investigated using solid state spectroscopy and microscopy techniques including solid state NMR, Near Infrared Spectroscopy, powder X-ray Diffraction and Single crystal X-ray. A sensitive seed detection test was developed.

RESULTS

Ritonavir polymorphs were thoroughly characterized and the structures determined. An unusual conformation was found for form II that results in a strong hydrogen bonding network A possible mechanism for heterogeneous nucleation of form II was investigated.

CONCLUSIONS

Ritonavir was found to exhibit conformational polymorphism with two unique crystal lattices having significantly different solubility properties. Although the polymorph (form II) corresponding to the "cis" conformation is a more stable packing arrangement, nucleation, even in the presence of form II seeds, is energetically unfavored except in highly supersaturated solutions. The coincidence of a highly supersaturated solution and a probable heterogeneous nucleation by a degradation product resulted in the sudden appearance of the more stable form II polymorph.

Transcriptional activation of heat shock protein 27 gene expression by 17beta-estradiol and modulation by antiestrogens and aryl hydrocarbon receptor agonists

Heat shock protein 27 (Hsp 27) is expressed in mammary tumors and may play a role in tumor growth and response to anti-neoplastic drug therapy. 17beta-Estradiol (E2) induces Hsp 27 mRNA levels in MCF-7 human breast cancer cells, and we have investigated the comparative inhibitory mechanisms using the aryl hydrocarbon receptor (AhR) agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the direct-acting antiestrogen ICI 164,384. TCDD inhibited E2-induced Hsp 27 gene expression and analysis of the Hsp 27 gene promoter showed that the inhibitory response was associated with AhR interactions with a pentanucleotide motif at -3 to +2 in the promoter that corresponded to the core sequence of a dioxin responsive element. In contrast, ICI 164,384 induced Hsp 27 gene expression and reporter gene activity in MCF-7 cells and this represents one of the few examples of the estrogen receptor-alpha (ERalpha) agonist activity of the 'pure' antiestrogen ICI 164,384.

Transcriptional activation of c-fos protooncogene by 17beta-estradiol: mechanism of aryl hydrocarbon receptor-mediated inhibition

17Beta-estradiol (E2) induced c-fos protooncogene mRNA levels in MCF-7 human breast cancer cells, and maximal induction was observed within 1 h after treatment. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibited the E2-induced response within 2 h. The molecular mechanism of this response was further investigated using pFC2-CAT, a construct containing a -1400 to +41 sequence from the human c-fos protooncogene linked to a bacterial chloramphenicol acetyltransferase (CAT) reporter gene. In MCF-7 cells transiently transfected with pFC2-CAT, 10 nM E2 induced an 8.5-fold increase of CAT activity, and cotreatment with 10 nM TCDD decreased this response by more than 45%. Alpha-Naphthoflavone, an aryl hydrocarbon receptor (AhR) antagonist, blocked the inhibitory effects of TCDD; moreover, the inhibitory response was not observed in variant Ah-nonresponsive MCF-7 cells, suggesting that the AhR complex was required for estrogen receptor cross-talk. The E2-responsive sequence (-1220 to -1155) in the c-fos gene promoter contains two putative core pentanucleotide dioxin-responsive elements (DREs) at -1206 to -1202 and -1163 to -1159. In transient transfection assays using wild-type and core DRE mutant constructs, the downstream core DRE (at -1163 to -1159) was identified as a functional inhibitory DRE. The results of photo-induced cross-linking, gel mobility shift, and in vitro DNA footprinting assays showed that the AhR complex interacted with the core DRE that also overlapped the E2-responsive GC-rich site (-1168 to -1161), suggesting that the mechanism for AhR-mediated inhibitory effects may be due to quenching or masking at the Sp1-binding site.

Evaluation of two-test serodiagnostic method for early Lyme disease in clinical practice

The Centers for Disease Control and Prevention (CDC) recommend a two-test approach for the serodiagnosis of Lyme disease (LD), with EIA testing followed by Western immunoblotting (WB) of EIA-equivocal and -positive specimens. This approach was compared with a simplified two-test approach (WB of EIA equivocals only) and WB alone for early LD. Case-patients with erythema migrans (EM) rash >/=5 cm were recruited from three primary-care practices in LD-endemic areas to provide acute- (S1) and convalescent-phase serum specimens (S2). The simplified approach had the highest sensitivity when either S1 or S2 samples were tested, nearly doubling when S2 were tested, while decreasing slightly for the other two approaches. Accordingly, the simplified approach had the lowest negative likelihood ratio for either S1 or S2. For early LD with EM, the simplified approach performed well and was less costly than the other testing approaches since less WB is required.

Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit

With the availability of more stable radiopharmaceuticals, the ictal single photon emission computed tomography (SPECT) perfusion study has emerged as a useful noninvasive functional neuroimaging tool in the presurgical evaluation of patients with medically intractable partial epilepsy. The purpose of this study was to determine whether the development of a program using trained electroencephalography (EEG) technologists to perform ictal injections in the epilepsy monitoring unit enabled a more efficient delivery of radiopharmaceuticals and therefore a higher specificity and sensitivity of outcome. All patients admitted to the epilepsy monitoring unit for prolonged video/EEG monitoring as part of the presurgical evaluation were eligible for completion of an ictal SPECT study using a three-way needle-free apparatus. Over a 19-month period, 85 (77%)) of 110 eligible patients were successfully injected during typical partial seizures. Various factors were analyzed including latency of ictal injection (27.3+/-20.8 [S.D.] s), radiopharmaceutical wastage (40% dose utilization), radiation safety parameters (1.6% contamination rate), and preliminary data of localizing value. Our results show that ictal SPECT can be a safe, noninvasive procedure completed on a routine basis in the epilepsy monitoring unit when appropriately trained support staff are utilized as part of a structured multidisciplinary program.

Ah receptor agonists as endocrine disruptors: antiestrogenic activity and mechanisms

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds induce a broad spectrum of biochemical and toxic responses and disrupt multiple endocrine pathways. Research in this laboratory has focused on characterizing aryl hydrocarbon receptor (AhR)-mediated antiestrogenicity in the rodent uterus and mammary and in human breast cancer cells. TCDD inhibits multiple estrogen (E2)-induced responses in these tissues including development or growth of human mammary and endometrial cancer cells, carcinogen-induced mammary cancer in rats, and mammary cancer in mice bearing breast cancer cell xenografts. The mechanisms of AhR-mediated antiestrogenicity are complex; however, studies on the molecular biology of cross-talk between the AhR and estrogen-receptor (ER) signaling pathways have been initiated using several E2-regulated genes as models. The results indicate that the nuclear AhR complex targets specific genomic core inhibitory dioxin responsive elements (iDREs) in promoter regions of some E2-responsive target genes to inhibit hormone-induced transactivation. The pS2, cathepsin and c-fos genes have functional iDREs, whereas the iDRE in the progesterone receptor gene promoter was not functional. Research has also focused on development of AhR-based antiestrogens which inhibit mammary tumor development and growth but do not exhibit prototypical AhR-induced toxic responses.

Estrogen-induced retinoic acid receptor alpha 1 gene expression: role of estrogen receptor-Sp1 complex

Retinoic acid receptor alpha 1 (RAR alpha 1) gene expression is induced by 17 beta-estradiol (E2) in estrogen receptor (ER)-positive breast cancer cells, and the -100 to -49 region of the RAR alpha 1 gene promoter was previously shown to be required for E2-responsiveness. This region of the RAR alpha 1 promoter was further analyzed using the following oligonucleotides: -100 to -49 (RAR4); -79 to -56 (RAR3); -79 to -49 (RAR2); -100 to -58 (RAR1); and their derived promoter reporter constructs (pRAR4, pRAR3, pRAR2, and pRAR1). In transient transfection studies in MCF-7 human breast cancer cells, pRAR2 and pRAR1 were E2-responsive; both of the RAR alpha 1 gene promoter inserts contained two GC-rich sites and bound Sp1 protein in gel mobility shift assays. Using wild-type [32P]RAR2 and oligonucleotides mutated in one or both GC-rich sites, it was shown that ER enhanced Sp1 binding to both sites, but a ternary ER-Sp1-DNA complex was not observed in gel mobility shift assays. In transient transfection assays, each of the GC-rich motifs were sufficient for E2-induced transactivation. In ER-negative MDA-MB-231 cells transiently transfected with pRAR2, E2 responsiveness was observed only in cells cotransfected with wild-type ER or 11C-ER containing a deletion of the DNA-binding domain but not with ER variants that express activation function-1 (AF-1) or AF-2. Using a similar approach, it was shown that the GC-rich sites in RAR1 were also sufficient for ER activation. These results demonstrate that interaction of a transcriptionally active ER/Sp1 complex with GC-rich motifs is required for hormone inducibility of the downstream region of the RAR alpha 1 gene promoter.

Estrogen-induced c-fos protooncogene expression in MCF-7 human breast cancer cells: role of estrogen receptor Sp1 complex formation

17Beta-estradiol (E2) induces c-fos protooncogene expression in MCF-7 human breast cancer cells, and previous studies in HeLa cells identified an imperfect palindromic estrogen-responsive element (-1212 to -1200) that was required for trans-activation. In contrast, the estrogen-responsive element was not required for E2 responsiveness in MCF-7 cells, and using a series of constructs containing wild-type (pF1) and mutant 5'-flanking sequences (-1220 to -1155) from the c-fos protooncogene promoter in transient transfection assays, it was shown that a GC-rich motif (5'-GGGGCGTGG) containing an imperfect Sp1-binding site was required for hormone-induced activity. This sequence also bound Sp1 protein in gel mobility shift assays, and coincubation with the estrogen receptor (ER) enhanced Sp1-DNA binding. E2 and 4'-hydroxytamoxifen, but not ICI 164,384, induced reporter gene activity in cells transiently transfected with pF1. E2 induced reporter gene activity in MDA-MB-231 breast cancer cells transiently cotransfected with pF1 and wild-type ER or variant ER in which the DNA-binding domain was deleted (HE11); plasmids expressing N-terminal or C-terminal domains of the ER containing activator function-1 or -2, respectively, were inactive in these assays. In contrast, only wild-type ER mediated 4'-hydroxytamoxifen-induced activity. Induction of c-fos protooncogene expression by E2 in MCF-7 cells is dependent on the formation of a transcriptionally active ER/Sp1 complex that binds to a GC-rich enhancer element.

Formulation and characterization of new layered diffusional matrices for zero-order sustained release

Statistical designs were used to study the effect of certain matrix formulation variables on the vitro release of a model compound, pseudoephedrine hydrochloride, from layered diffusional matrices designed for zero-order sustained release. These matrices consist of non-swellable, hydrophobic middle layers containing the active drug to which hydrophilic and/or hydrophobic barrier layers are press-coated. In general, linear release profiles can be obtained by applying hydrophilic barrier layers on both faces of a hydrophobic matrix tablet, or by applying a hydrophilic barrier layer on one face and a hydrophobic barrier layer on the other face of the matrix tablet. However, formulation and matrix variables in the barrier layers need to be controlled in order to achieve zero-order drug release from a hydrophobic matrix tablet coated with hydrophobic barrier layers on both faces.

Functional synergy between the transcription factor Sp1 and the estrogen receptor

A GC-rich oligonucleotide containing an estrogen responsive element (ERE) half-site from the heat shock protein 27 (Hsp 27) gene promoter (-105 to -84) [ie. GGGCGGG(N)10GGTCA; Sp1(N)10ERE] forms a complex with the Sp1 and estrogen receptor (ER) proteins. Moreover, promoter-reporter constructs containing this sequence (-108 to -84 or -108 to +23) are also estrogen-responsive. Mutation of the ERE half-site in the Hsp 27-derived oligonucleotides did not result in loss of estrogen responsiveness in transient transfection studies, suggesting that estrogen inducibility was mediated through the Sp1-DNA motif. Gel mobility shift assays using 32P-labeled wild type and ERE mutant Sp1(N)10ERE and consensus Sp1 oligonucleotides showed that Sp1 protein formed a DNA-protein complex with all three nucleotides, and the intensities of retarded bands were enhanced by coincubation with wild type ER and 11C-ER, which does not contain the DNA-binding domain. ER mutants in which N-terminal (19C-ER) and C-terminal (15C-ER) regions were deleted did not enhance Sp1-DNA binding or hormone-induced transactivation of GC-rich promoter-reporter constructs in ER-negative MDA-MB-231 cells, whereas both wild type and 11C-ER restored inducibility. Immunoprecipitation studies also confirmed that the Sp1 and ER proteins physically interact. The interaction of the Sp1 and ER proteins and the resulting enhanced Sp1-DNA binding is observed in the presence or absence of estrogen (hormone-independent), whereas transactivation of promoter-reporter constructs is estrogen-dependent. Thus, the results illustrate a new estrogen-dependent transactivation pathway that involves ER-protein interactions and is ERE-independent.

Identification of a functional imperfect estrogen-responsive element in the 5'-promoter region of the human cathepsin D gene

17beta-Estradiol (E2) induces cathepsin D gene expression in MCF-7 human breast cancer cells. Previous studies have identified an Sp1-imperfect estrogen-responsive element (ERE) half-site [GGGCGG(N)23ACGGG] (-199 to -165) in the promoter region which forms an Sp1-estrogen receptor (ER) complex and confers E2 responsiveness on the corresponding Sp1-ERE-chloramphenicol acetyl transferase (CAT) construct. Further analysis of downstream regions of the promoter identified a CGCCC(N)3TGACC sequence (-119 to -107) which is homologous to the adenovirus major late promoter element (MLPE) and binds the ER to form a retarded band in a gel electrophoretic mobility shift assay. The corresponding promoter-CAT construct is also E2-inducible. The MLPE resembles an imperfect palindromic ERE containing imperfect (5') and perfect (3') ERE half-sites; analysis of oligonucleotides with mutations in these half-sites shows that only the perfect ERE half-site is required for binding the ER, whereas both sites are required for transactivation. In vivo exonuclease III footprinting showed that treatment with E2 also enhanced binding at the MLPE site. Identification of this second functional enhancer sequence in the 5'-promoter region of cathepsin D is consistent with the increasingly complex cell-specific regulation of hormone-responsive genes.

Identification of a motif within the 5' regulatory region of pS2 which is responsible for AP-1 binding and TCDD-mediated suppression

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related compounds modulate several endocrine systems by altering hormone synthesis, enhancing ligand metabolism, and down-regulating receptor levels/binding activity. Previous studies have demonstrated that TCDD inhibits the 17beta-estradiol (E2)-induction of pS2, a human breast cancer prognostic marker. This inhibition occurs at the gene expression level and is Ah receptor (AhR)-mediated. Analysis of the 5' regulatory region has identified three motifs which resemble dioxin response element (DRE) core sequences. pS2-regulated luciferase deletion constructs identified the DRE-like motif located at -527 to -514 as being required for TCDD-mediated suppression. A point mutation within this core motif (T-518C) abolished the inhibition by TCDD while UV-induced protein-DNA cross-linking and competitive gel retardation assays demonstrated AhR complex binding to this motif. Further study of this region also revealed an adjacent putative AP-1 site, diverging by one base pair from the consensus sequence. Gel retardation assays using TPA-treated MCF-7 cell nuclear extracts showed an induced complex binding to the AP-1-like site. Competition studies and antibody supershifts confirmed that the retarded complex consists of AP-1-like proteins. pS2-regulated luciferase constructs containing mutations specific to the AP-1-like motif greatly diminished the inducibility in response to E2. These results suggest that an interaction between AhR complexes and AP-1-like proteins may be responsible for TCDD-mediated inhibition of E2-induced pS2 expression.

Mechanism of inhibition of MDA-MB-468 breast cancer cell growth by 2,3,7,8-tetrachlorodibenzo-p-dioxin

Treatment of estrogen receptor (ER)-negative MDA-MB-468 human breast cancer cells with 10 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced formation of a nuclear aryl hydrocarbon (Ah) receptor complex as determined by ligand-binding and gel electrophoretic mobility shift assays. TCDD also induced CYP1A1-dependent activity in MDA-MB-468 cells, which represents the first ER-negative Ah receptor-positive human breast cancer cell line that has been identified. Treatment of this cell line with TCDD and related compounds also caused a 50% inhibition of cell growth, which resembled the growth inhibitory effects previously reported for epidermal growth factor (EGF). However, EGF expression is minimal in this cell line and is not induced by TCDD; moreover, EGF and TCDD induced a different pattern of oncogene expression and apoptosis in MDA-MB-468 cells. In contrast, TCDD caused a rapid and sustained induction of transforming growth factor alpha (TGF alpha) gene expression and secreted protein (nearly 2-fold); moreover, the growth-inhibitory effects of TCDD could be blocked by antibodies to the EGF receptor. In a separate experiment, it was shown that TGF alpha also inhibited growth of MDA-MB-468 cells. The results of this study indicate that the mechanism of growth inhibition of MDA-MB-468 cells by TCDD is due to induction of TGF alpha, which is a potent antimitogen in this cell breast cancer line.

Role of estrogen receptor/Sp1 complexes in estrogen-induced heat shock protein 27 gene expression

Treatment of MCF-7 human breast cancer cells with 10 nM 17 beta-estradiol (E2) resulted in a 2-fold induction of heat shock protein (Hsp) 27 mRNA levels, and this response persisted for up to 24 h. The 5'-promoter region of the gene was further investigated to identify genomic sequences associated with E2 responsiveness. An Sp1 and half-palindromic estrogen response element (ERE) separated by 10 nucleotides, GGGCGGG(N)10GGTCA, were identified at -105 to -84, and formation of the Sp1/estrogen receptor (ER) complex was investigated by in vitro assays using synthetic Hsp 27-[32P]Sp1/ERE oligonucleotides in a gel mobility shift assay and transient transfection studies using short (-108/-84) and long (-108/+23) 5'-promoter sequences linked to a thymidine kinase promoter and the bacterial chloramphenicol acetyl transferase (CAT) reporter gene (Hsp-CATs and Hsp-CATl, respectively). Incubation of nuclear extracts from MCF-7 cells with an Hsp 27-[32P]Sp1/ERE oligonucleotide results in formation of an Sp1/ER complex. The formation of this complex was inhibited by coincubation with unlabeled Sp1/ERE, ERE, and Sp1 oligonucleotides and by preincubation with ER or Sp1 antibodies (immunodepletion). In addition, the complex was supershifted by coincubation with ER antibodies. Mutation of either Sp1 or ERE sites also decreases formation of the retarded band. E2 induced CAT activity in MCF-7 cells transiently transfected with either Hsp-CATs or Hsp-CATl plasmids. It was also demonstrated that E2 did not significantly induce CAT activity in MCF-7 cells transiently transfected with Hsp-CATl-containing mutations in both the Sp1 and ERE sites. The results of this study demonstrate that an Sp1/ER complex is involved in E2-induced Hsp 27 gene expression.

Effect of transient expression of the oestrogen receptor on constitutive and inducible CYP1A1 in Hs578T human breast cancer cells

Hs578T human breast cancer cells are an oestrogen receptor (ER)-negative cell line. Treatment of these cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in formation of a 6.9 S nuclear aryl hydrocarbon (Ah) receptor complex, which bound to a [32P]dioxin-responsive element in a gel electrophoretic mobility shift assay. However, TCDD does not induce CYP1A1 gene expression or chloramphenicol acetyl transferase (CAT) activity in cells transiently transfected with pRNH11c or pMCAT5.12, which are Ah-responsive plasmids derived from the 5'-flanking region of the human and murine CYP1A1 genes respectively. Restoration of Ah responsiveness was investigated by co-transfecting Hs578T cells with pRNH11c or pMCAT5.12 and plasmids that express the ER (hER), Ah receptor (AhR) and AhR nuclear translocator (Arnt) proteins. ER expression resulted in significantly increased basal CAT activity; however, TCDD did not induce CAT activity in the transiently transfected cells. Expression of the AhR or Arnt proteins did not alter basal or inducible CAT activity. Expression of N- or C-terminal truncated ER in Hs578T resulted in differential regulation of Ah responsiveness. In Hs578T cells transiently expressing the ER, which contains C-terminal deletions (amino acids 282-595), basal CAT activity was also increased; however, Ah responsiveness was not restored. In contrast, transient expression of N-terminal-deleted (amino acids 1-178) ER resulted in a marked decrease in basal CAT activity but a restoration of Ah responsiveness. These results suggest that basal and inducible CAT activity in Hs578T cells transiently transfected with pRNH11c is modulated differentially by ER domains that are present in the N- and C-terminal regions of the ER.

Molecular mechanism of inhibition of estrogen-induced cathepsin D gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in MCF-7 cells

17 beta-Estradiol (E2) induces cathepsin D mRNA levels and intracellular levels of immunoreactive protein in MCF-7 human breast cancer cells. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alone does not affect cathepsin D gene expression in this cell line; however, in cells cotreated with TCDD and E2, TCDD inhibited E2-induced cathepsin D mRNA levels, the rate of gene transcription, and levels of immunoreactive protein. The inhibitory responses were observed within 30 to 120 min after the cells were treated with TCDD. TCDD also inhibited E2-induced secreted alkaline phosphatase activity in aryl hydrocarbon (Ah)-responsive MCF-7 and wild-type mouse Hepa 1c1c7 cells cotransfected with the human estrogen receptor (hER) and the pBC12/S1/pac plasmid, which contains the 5' promoter region (-296/+57) of the cathepsin D gene and an alkaline phosphatase reporter gene. The E2-responsive ER/Sp1 sequence (-199 to -165) in the cathepsin D 5' region contains an imperfect GTGCGTG (-175/-181) xenobiotic responsive element (XRE); the role of this sequence in Ah responsiveness was investigated in gel electrophoretic mobility shift assays and with plasmid constructs containing a wild-type ER/Sp1 oligonucleotide or a mutant ER/Sp1-"XRE" oligonucleotide containing two C-->A mutations in the XRE sequence (antisense strand). In plasmid constructs which contained a chloramphenicol acetyltransferase reporter gene and the wild-type ER/Sp1 promoter sequence, E2-induced chloramphenicol acetyltransferase activity and mRNA levels were inhibited by TCDD whereas no inhibition was observed with the mutant ER/Sp1-"XRE" plasmids. Electrophoretic mobility shift assays showed that the nuclear or transformed cytosolic Ah receptor complex blocked formation of the ER-Sp1 complex with the wild-type but not the ER/Sp1 mutant oligonucleotide. Moreover, incubation of the wild-type bromodeoxyuridine-substituted ER/Sp1 oligonucleotide with the nuclear Ah receptor complex gave a specifically bound cross-linked 200-kDa band. These data demonstrate that Ah receptor-mediated inhibition of E2-induced cathepsin D gene expression is due to disruption of the ER-Sp1 complex by targeted interaction with an overlapping XRE.

Mechanism of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated decrease of the nuclear estrogen receptor in MCF-7 human breast cancer cells

Treatment of MCF-7 cells with 1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 1 nM [3H]17 beta-estradiol resulted in decreased radiolabeled nuclear estrogen receptor (ER) levels as determined by velocity sedimentation analysis. In parallel studies, nuclear extracts from TCDD-treated cells also exhibited decreased binding to a consensus 32P-genomic estrogen responsive element (ERE) as determined in a gel mobility shift assay. Time-course studies showed that the decreases in nuclear ER and ER-ERE binding in TCDD-treated cells were observed within 1 to 3 h after treatment, respectively, and persisted for up to 24 h. Cycloheximide (10 microM) did not affect the TCDD-mediated response, whereas 1 microM alpha-naphthoflavone, an aryl hydrocarbon (Ah) receptor antagonist, partially blocked downregulation of nuclear ER binding by TCDD. TCDD did not significantly affect steady state ER mRNA levels as determined by Northern analysis or the rate of ER gene transcription in a nuclear run-on assay. These results suggest that the TCDD-mediated decrease in nuclear ER levels is an Ah receptor-mediated response which occurs at the translational or post-translational level.

What hospitals expect today from clinical systems

Technology will always be a factor in hospital information system buys. But customers are increasingly looking for vendors that create a sincere, responsive sales relationship. In the end, the quality of support and understanding users receive can make or break a sale.

Thermodynamics in the prediction of the solubilities of binary mixtures of the diastereoisomers and enantiomers of ephedrine

Equations derived from the Clausius-Clapeyron and Prigogine-Defay equations were used to determine the free energy of mixing for diastereoisomers and enantiomers from heats of fusion and transition temperature data. These equations are applied to the thermodynamics of mixing of the six binary equimolar combinations of (1R,2S)-ephedrine, (1S,2R)-ephedrine; and (1R,2R)- and (1S,2S)-pseudoephedrine isomers. The relative equilibrium solubility of the binary mixtures in water is consistent with thermodynamic calculations.

Postpartum haemorrhage--a continuing problem

The factors responsible for postpartum haemorrhage (PPH) in singleton vaginal deliveries, not complicated by a retained placenta, were identified by comparing labour characteristics in 86 women who had a PPH (blood loss greater than 500 ml) with 351 women whose blood loss at delivery was less than 350 ml. Primiparity, induction of labour by amniotomy/oxytocin, forceps delivery, long first and second stages, oxytocin compared with syntometrine (oxytocin plus ergometrine maleate), as a prophylactic oxytocic, were identified as significant risk factors. Epidural analgesia contributed indirectly to an increase in the risk of postpartum haemorrhage. The changes in labour ward practice over the last 20 years have resulted in the re-emergence of PPH as a significant problem.

Comparison of psychomotor skills and amnesia after induction of anesthesia with midazolam or thiopental

In two groups of 31 healthy patients undergoing minor elective surgery, anesthesia was induced intravenously with either midazolam maleate, 0.2 mg/kg, or thiopental, 3.5 mg/kg. All subjects received 2 micrograms/kg fentanyl 5 min before the induction agents. Induction time with midazolam was significantly longer than with thiopental (97.1 +/- 10.9 sec vs 59.4 +/- 5.0 sec) and time to orientation postoperatively was significantly longer after midazolam (31.7 +/- 4.2 min vs 11.0 +/- 1.1 min). Continued recovery after orientation, measured by a series of psychomotor tests, was also significantly longer with midazolam than with thiopental. Anterograde amnesia was evident in 84.8% of the midazolam treated patients and in only 31.4% of the thiopental group. This degree of absence of recall was acknowledged positively by the affected patients. The protracted recovery period may limit the use of midazolam in short surgical procedures.

Surfboard-related ocular injuries

Three cases of ocular trauma caused by surfboards are reported. The severe nature of the injuries is discussed and the prevalence of this type of injury is reviewed.

Hemodialysis clearance of pentobarbital during continuous infusion

The hemodialysis clearance of pentobarbital during continuous infusion was determined in a 34-year-old man in acute renal failure. Pentobarbital specimens were obtained simultaneously from arterial blood entering and leaving the dialysis machine at five 1-h intervals. The mean hemodialysis clearance of pentobarbital was 22.3 ml/min. Pentobarbital concentration was relatively unaffected throughout the dialysis period, because of the high dose and continuous infusion of a drug with low hepatic intrinsic clearance and a short dialysis period. A large contribution to total body clearance was not evident, and dosage adjustment would have been unwarranted.

Hazardous materials management and control program at Oak Ridge National Laboratory--health protection

Maintaining reasonable control of all hazardous materials used in a large research laboratory can be a formidable task. At Oak Ridge National Laboratory, a Hazardous Material Coordinator for Health Protection (HMC-Hlth) and a Hazardous Material Coordinator for Environmental Protection (HMC-Env) control hazardous materials from acquisition to disposal. The HMC-Hlth, a member of the Industrial Hygiene Department, is responsible for control of the purchase and use of hazardous materials. If the material has not had a hazard evaluation, the user is required to contact the HMC-Hlth to find out if the material is hazardous before ordering it. If the material is hazardous, the user must get permission from his divisional representative to purchase it. The user is required to fill out Part 2 of a Hazardous Material Control Card (HMCC), describing the proposed use and location of the material and to return HMCC to the HMC-Hlth. This allows the Industrial Hygiene Department to evaluate the use of the materials and to take air samples as needed. Part 1 of the HMCC also contains computer printed information on the hazards.

Comparison of dye dilution method to radionuclide techniques for cardiac output determination in dogs

A study was undertaken to identify the most accurate 99mTc-labeled radiopharmaceutical and to determine the accuracy of a noninvasive radionuclide technique (antecubital injection and precordial detection) for cardiac output determinations. Phase I employed sodium pertechnetate, stannous pyrophosphate with sodium pertechnetate, technetium-99m red blood cells, and technetium-99m human serum albumin as radionuclide tracers. Cardiac output was determined by the dye dilution method and then by the invasive radionuclide technique. The radiopharmaceutical was injected into the same intracardiac catheter used in the dye dilution method. Seven to 10 mongrel dogs were used to test the accuracy of each radiopharmaceutical. A paired t test and regression analysis indicated that technetium-99m human serum albumin was the most accurate radiopharmaceutical for cardiac output determinations, and the results compared favorably to those obtained by the dye dilution method. In Phase II, technetium-99m human serum albumin was used as the radionuclide tracer for cardiac output determinations with the noninvasive technique. The results compared favorably to those obtained by the dye dilution method. Regression analysis indicated a correlation coefficient of 0.91. A paired t test demonstrated that the difference between the two methods was not statistically significant (p greater than 0.05). The data suggest that a noninvasive radionuclide technique using cardiac output determinations in humans.

The toxic materials control program at ORNL revisited

For large industrial and research operations, maintaining reasonable control of all toxic materials used in their operations can be a formidable task. A system utilizing cards has been developed which serves a dual purpose, informing the user regarding hazards of a particular material and also facilitating appropriate workplace surveillance during its use. Selected hazard data and spill notification message, if applicable, are printed on the card. The card contains a label which the user detaches and affixes to the container. This label classifies the material according to toxicity, flammability, reactivity, special properties on a 0 through 4 hazard rating, and spill message if needed to comply with environmental requirements.

Effect of particle number on lung perfusion images: concise communication

Twelve normal mongrel dogs were injected with decreasing numbers of 99mTc-labeled macroaggreagated albumin particles (99mTc-MAA), and lung images were recorded using both parallel-hole and pinhole collimators. The quality of normal lung images was found to decrease with decreasing numbers of injected radiolabeled particles (from 10,000 to 250 particles per injection). The quality was unaffected by adding carrier MAA. The minimum number of particles compatible with a good-quality image of the normal human lung is approximately 60 radiolabeled particles per gram of lung.

Nonverbal communication: an alternate mode of communication for the child with severe cerebral palsy

This paper reports the results of a study to determine the feasibility and usefulness of teaching severely mentally retarded cerebral-palsied children a nonverbal means of communication. All the children easily learned to use the communication device as a means of signaling distress and the need for attention. Most of them learned to use it to communicate their basic needs. The extent to which they used the communication system depended heavily on the attitude of the staff.