Level of agreement between three-dimensional transthoracic and transesophageal echocardiography for mitral annulus evaluation: A feasibility and comparison study.

INTRODUCTION: Mitral annulus assessment is of utmost importance for the management of patients with mitral valve (MV) abnormalities, as it helps to determine the decision for surgical or transcatheter treatment. Three-dimensional (3D) transesophageal echocardiography (TOE) has been the only reliable echocardiographic method for the evaluation of the mitral annulus by now. However, newer transthoracic echocardiography (TTE) 3D probes have enabled to provide accurate measurements as well and become a valuable tool when TOE is contraindicated. The aim of this study is to assess the feasibility of 3D TTE analysis of mitral annulus and the level of agreement with 3D TOE measurements. METHODS: A total of 121 consecutive patients were assessed with 3D TTE and TOE. All mitral annulus parameters were retrospectively analyzed with the dedicated 4D autoMVQ application. Bland-Altman analysis and intraclass correlation coefficient were used for the comparison and agreement between the two methods. Half of our patients had normal mitral valves and served as control group, while the other half had various mitral valve pathologies. RESULTS: AutoMVQ analysis was not feasible in 11 out of 121 TTE examinations (91% feasibility) and in 4 out of 121 TOE examinations (96% feasibility). Mitral annular area and perimeter were slightly larger in TTE than those measured by TOE (12.7 ± 3.6 vs. 12.4 ± 3.2 cm2 for area and 12.7 ± 1.7 vs. 12.5 ± 1.6 cm for perimeter), however still showing strong correlation (r = .942 and r = .922, respectively). The majority of mitral valve measurements (anterior-posterior, medial-lateral and commissural diameter, aorto-mitral angle and anterior leaflet length) were similar among the two methods with strong correlation (r > .80). Inter-trigonal distance, posterior leaflet length and tenting height showed weaker agreement between TTE and TOE (r = .687, r = .687, r = .634, respectively). Mitral annular dimensions (by 3D area) were found to be significantly larger in patients with MV pathology (13.5 ± 3.5 vs. 11 ± 2.3 cm2 ), atrial fibrillation (14.4 ± 3 vs. 11.4 ± 2.8 cm2 ), left ventricular (13.8 ± 3.1 vs. 11.7 ± 3.1cm2 ) and left atrial dilatation (13 ± 3.3 vs. 10.6 ± 2.3cm2 ) compared to the individuals in the control group (p < .001 for all comparisons). CONCLUSIONS: Assessment of the MV with 3D TTE with dedicated MVQ software is feasible and accurate, showing strong correlation and agreement with TOE measurements.

Clinical and radiographic assessment of implant-supported rehabilitation of partial and complete edentulism: a 2 to 8 years clinical follow-up.

OBJECTIVE: The aim of this study was to find out the rates of survival and success of implant rehabilitation, and the influence of some risk indicators on the medium- and long-term prognosis. PATIENTS AND METHODS: Of the 102 patients eligible for this study rehabilitated with dental implants during the years 2009-2015, 75 patients with 156 implants of different implant systems placed and loaded by the same team were recalled. For each subject, pocket-probing depth, bleeding on probing, plaque buildup, mobility of the fixtures, and the presence/absence of prosthetic complications were recorded. Radiographic evaluation was based on the analysis of bone levels around the fixtures, as shown by intraoral radiographs. RESULTS: The average follow-up was 4.4 years, ranging from 1.5 to 7.8 years. One hundred and fifty-four of the implants survived, while two implants failed; 98.8% of the prostheses survived, while 75.9% were successful. Success was achieved in 90.4% of implants and in 80% of patients. The sample showed average radiographic bone resorption of 1.09 mm. The average pocket probing depth was 2.79 mm. Bleeding on probing was found in 18% of all sites, and 59.6% of implants showed bleeding on probing in at least one site. Mucositis was found in 90% of patients, and peri-implantitis was found in 16% of patients. CONCLUSIONS: The rates of success and survival showed the reliability of implant therapy. Plaque accumulation, smoking and upper jaw location, seem to increase the risk of failure of implant-supported rehabilitation.

Stearoyl-CoA desaturase-1, a novel target of omega-3 fatty acids for reducing breast cancer risk in obese postmenopausal women.

BACKGROUND/OBJECTIVES: Conversion of saturated fatty acids to monounsaturated fatty acids by the enzyme stearoyl-Co-A-desaturase (SCD-1) is emerging as a major factor in promoting carcinogenesis including breast cancer. The aim of our study was to explore the regulation of SCD-1 by Raloxifene and omega-3 fatty acids in women at increased risk of breast cancer based on high breast density. SUBJECTS/METHODS: As a reflection of SCD-1 activity, we measured the ratios of palmitoleic acid (C16:1n7) to palmitic acid (C16:0) (SCD-16) and oleic acid (C18:1n9) to steric acid (C18:0) (SCD-18) in plasma samples of postmenopausal women enrolled in our clinical trial (NCT00723398) designed to test the effects of the antiestrogen, Raloxifene and/or the omega-3 preparation Lovaza, on breast density, a validated biomarker of breast cancer risk. RESULTS: We report that Lovaza but not Raloxifene-reduced SCD-16 and SCD-18 for the 2-year duration of the trial. Importantly, decreasing levels of SCD-16 and SCD-18 were associated with a progressive reduction in breast density but only in obese women (body mass index ⩾30). CONCLUSIONS: Body mass index-related factors play an important role in the reduction of breast density and hence breast cancer risk by omega-3 fatty acids. SCD-1 may be a useful biomarker in future clinical trials testing the benefit of nutritional interventions in reducing obesity-associated breast cancer risk.

Lymphocyte subsets as biomarkers of therapeutic response in Fingolimod treated Relapsing Multiple Sclerosis patients.

We investigated, lymphocyte count (LC) and lymphocyte subpopulations (LS) in a real life setting of Fingolimod (FTY) treated Relapsing MS (RMS) patients. Peripheral blood counts with LS, relapses and MRI scans were recorded in a cohort of 119 FTY patients, during one year of treatment. Simple and multivariate logistic regression models, were performed. ROC analysis identified cut-off values of LS predicting a higher risk of relapses and of Gd+ lesions. We demonstrated a FTY-induced re-modulation of the immune system, suggesting that LS in RMS FTY treated patients can predict the clinical response to the drug.

The relationship between oestrogen and executive functioning in ALS females with emerging Frontotemporal Lobar Degeneration (FTLD) supports a neuroendocrine model of FTLD attenuation.

OBJECTIVE: The prevalence of ALS cognitive or behavioural impairment (ci or bi) consistent with Frontotemporal Degeneration (FTLD) approachs 50%, while ∼5-10% progress to dementia. Our goal was to explore ci and bi differencs between bulbar and limb onset, as well as the neuroprotective potential of oestrogen in emerging FTLD. METHODS: We applied Mann Whitney U to evaluate differences in cognitive and behavioural profiles between site of onset in 78 female and 83 male non-demented ALS participants classified by current consensus criteria with ci. For females, we also examined differences by oestrogen level. FINDINGS: Between group analyses found significantly worse Letter Fluency (LF) for bulbar onset, and worse Category Fluency (CF) for bulbar females. Significantly worse performance was found for low oestrogen females for LF and Similarities, with significantly worse LF for low oestrogen bulbar onset. No significant differences were found for behavioural subgroups, while moderate-severe range traits were higher in occurrence for bulbar and low oestrogen bulbar onset. CONCLUSIONS: Findings support our previously published mesocortical pathway associated "bottom-up" model of FTLD emergence in ALSbi, extending it with a hierarchal hypothesis involving ascending cerebellar pathways in ALSci and ALSbi, further suggesting a role for oestrogen in mitigating female FTLD progression.

The role of neutralizing antibodies to interferon-ß as a biomarker of persistent MRI activity in multiple sclerosis: a 7-year observational study.

PURPOSE: During interferon-ß (IFN-ß) therapy, up to 45 % of patients may develop neutralizing antibodies (NAbs), associated with a decreased efficacy of the drug. We investigated in a real-life setting the impact of NAbs on magnetic resonance imaging (MRI) outcomes in a population of 567 IFN-ß-treated relapsing-remitting (RR) multiple sclerosis (MS) patients up to 7 years. We also evaluated NAbs' role as a biomarker of the persistence of MRI disease activity. METHODS: Patients' sera were tested for NAbs' presence by cytopathic effect (CPE) assay every 6-12 months. MRI scans were performed every 12 months. Generalized hierarchical linear models accounting for within-patient correlation were used to analyze T1 gadolinium-enhancing and new T2 lesions. Moreover, further tests were carried out to assess the overall outcome difference from year 1 to year 7 according to NAb status and the possible interaction between NAb status and time of follow-up. RESULTS: Seventy-five patients (13.2 %) became NAb positive (NAb+) during the follow-up. Considering T1 gadolinium-enhancing (GD+) lesions, we observed a significantly higher incidence in NAb+ patients (52 %, p = 0.0091). Also for new T2 lesions, we found a higher incidence in NAb+ patients (50 %, p = 0.0075). The negative impact of NAbs on the MRI outcomes considered did not change during the follow-up. CONCLUSIONS: Our 7-year results show the negative effect of NAbs on MRI measures of disease activity and confirm their role as a surrogate marker of IFN-ß treatment efficacy.

Microbiologic evaluation of crevicular fluid in patients treated with platform switching and traditional implants.

BACKGROUND: The purpose of this study was to compare the microbiota around natural teeth and dental implants with different restorative platforms. Attention was focused on whether the microbiological environment could change according to the implant platform used i.e. traditional or Platform Switching implants. As the latter show less signs of bone resorption, a correlation with the presence of certain periodontal bacteria was suggested. METHODS: Seven partially edentulous patients with dental implants, either traditional or Platform Switching, were included in this study. All the implants were in function at least for 1 year. Gingival crevicular fluid samples were obtained before any periodontal probing from natural teeth and different implant platforms and assayed using DNA extraction and PCR sequences in order to determine quality and quantity of microbiota. Statistical analysis included chi square test were used to establish differences in the microbiological distribution between the two implant platforms. RESULTS: There were not statistical differences neither regarding the distribution of microbiota around natural teeth and implants nor between the two implant platforms. The presence of B.forsythus was revealed in the majority of the samples (from 90 to 100 percent) while A.actinomycetemcomitans was rarely found (from 0 o 25 percent). As for the other periodontal microbiota, their presence or absence showed a variation according to different sites or patients, without a predictable pattern. CONCLUSIONS: It was not possible to find a link between the colonization of certain types of bacteria and the reduction of bone loss which occurs around Platform Switching implants. Therefore the preservation of bone crest is only due to biomechanical aspects, which are related to the reposition of the implant-abutment interface away from the outer edge of the implant platform and from the bone.

Administration of omega-3 fatty acids and Raloxifene to women at high risk of breast cancer: interim feasibility and biomarkers analysis from a clinical trial.

BACKGROUND/OBJECTIVES: The antiestrogen, Raloxifene (Ral) is an effective breast cancer chemopreventive agent. Omega-3 fatty acids (n-3FA) may inhibit mammary carcinogenesis. On the basis of their mechanisms of action, we test the hypothesis that a combination of n-3FA and Ral may be superior in reducing select biomarkers of breast cancer risk in women. SUBJECTS/METHODS: Postmenopausal women at increased risk for breast cancer (breast density ≥ 25%) were randomized to: (1) no intervention; (2) Ral 60 mg; (3) Ral 30 mg; (4) n-3FA (Lovaza) 4 g and (5) Lovaza 4 g+Ral 30 mg for 2 years. Reduction in breast density is the primary end point of the study. We report preliminary data on feasibility, compliance and changes in secondary end points related to IGF-I signaling, estrogen metabolism, oxidative stress and inflammation in the first group of 46 women who completed 1 year of the study. RESULTS: All interventions were well tolerated with excellent compliance (96 ± 1% overall) by pill count and also supported by the expected rise in both serum n-3FA and n-3FA/Omega-6 fatty acids (n-6FA) ratio in women randomized to groups 4 and 5 (P<0.05). Lovaza decreased serum triglycerides and increased high-density lipoprotein (HDL) cholesterol compared with control (P<0.05 for both). Ral reduced serum IGF-1 in a dose-dependent manner (P<0.05) while Lovaza did not. Lovaza had no effect on IGF-1 or IGFBP-3. None of the other biomarkers were affected by our treatment. CONCLUSION: The combination of Lovaza and Ral is a feasible strategy that may be recommended in future breast cancer chemoprevention trials.

alpha-Defensin levels in whole saliva of totally edentulous subjects.

Salivary levels of alpha-defensins 1-4 and histatins 1, 3 and 5 were determined in 11 totally edentulous patients, 11 younger healthy adults with normal gingival mucosa (Control group I) and 8 subjects, age-matched with edentulous patients, having a minimum of 25 teeth (Control group II). Whole saliva was treated with trifluoroacetic acid and the acidic soluble fraction analyzed by High Performance Liquid Chromatography-Mass Spectrometry. The area of the extracted ion current peaks was used for peptide quantification. Levels of alpha-defensins1-4, but not of histatins, were significantly lower in totally edentulous patients with respect to both Control group I and Control group II. The two control groups did not show significant differences. The reduced level of oral alpha-defensins, which are mainly of crevicular origin, is most likely due to the absence of the gingival sulcus in the edentulous subjects. The near absence of alpha- defensins might be in part responsible for the higher vulnerability of the oral cavity to oral pathogen infections observed in totally edentulous patients.

Combined irinotecan and oxaliplatin in patients with advanced pre-treated pancreatic cancer.

OBJECTIVES: This study evaluated the clinical activity and toxicity of combination chemotherapy with irinotecan and oxaliplatin in patients with advanced pancreatic cancer that had progressed despite > or =1 course of a gemcitabine-containing regimen. METHODS: Thirty patients with metastatic pancreatic cancer and Karnofsky performance status > or =70 received oxaliplatin 60 mg/m2 on days 1 + 15 and irinotecan 60 mg/m2 on days 1 + 8 + 15 every 4 weeks. Patients were assessed on the basis of clinical benefit response, changes in serum tumour marker CA 19-9, objective tumour response, time to progressive disease (TTP), and survival. RESULTS: Six patients (20%) had clinical benefit response (median duration of 7.2 months). CA 19-9 levels were reduced > or =50% from baseline in 8 patients (26%) and remained stable in 8 patients. CT scans revealed that 3 patients (10%) had a partial response and 7 (23%) had stable disease. Two patients (7%) were down-staged and underwent surgery. Median TTP was 4.1 months, median survival was 5.9 months and the 1-year survival rate was 23.3%. The most serious adverse events were grade 3-4 leukopenia in 2 patients (6%), grade 3 neuropathy in 2 (6%) and grade 3 diarrhoea in 1 (3%). CONCLUSION: Chemotherapy with irinotecan and oxaliplatin is an active and well-tolerated combination in patients with advanced pre-treated pancreatic cancer.

Regional combined with systemic chemotherapy in unresectable biliary tract cancers: a phase II study.

Unresectable biliary tract cancers have a very poor prognosis. No good systemic chemotherapeutic regimen is available. This study aimed to evaluated the activity and toxicity of a novel approach of combined loco-regional and systemic chemotherapy. Twenty four patients with advanced or metastatic biliary tumors were treated with epiadriamycin 50 mg/m2 and cisplatin 60 mg/m2 administered bolus in proper hepatic artery on day 1, combined with systemic continuous infusion of 5-fluorouracil 200 mg/m2/day, from day 1 to day 14, every 3 weeks. The overall response rate was 8/24 (33%), including one complete response and 7 partial responses (stable disease 46%, progression 21%). The treatment was well tolerated with a minimal hematological toxicity; the major clinical problem was the deep venous thrombosis related to central venous catheter, that occurred in 5 patients (21%). Median overall survival was 14,6 months and 1-year and 2-year survival were 54% and 38% respectively. Performance status improved in 33% of patients and weight gain more than 7% was observed in 17%. This novel combined loco-regional and systemic chemotherapeutic regimen is active and safe for advanced biliary tract cancer patients.

[Neuromuscular occlusion in the orthodontic treatment of craniomandibular disorders. A clinical case]. / L'occlusione neuromuscolare nella terapia ortodontica del paziente con disordini craniomandibolari. Caso clinico.

In the last few years, it has been observed a considerable increase of cranio-mandibular disorders which presently represent one of the most common commitments for dentists and, in particular, for orthodontists. The aim of this paper is to evaluate the efficacy of Jankelson's therapeutic protocol, followed by an orthodontic treatment, in a patient with cranio-mandibular disorders associated with occlusal pathologies. The cranio-mandibular electromyography and kinesiography promoted by Jankelson provide objective diagnostic measurements, while tens, relaxing masticatory muscles, allows a correct recording of myocentric occlusion. In this case, the authors utilise these devices, according to a well established diagnostic and therapeutic protocol. The first step is purely gnatologic, and consists of the application of an orthotic to temporarily treat pain and dysfunction. The following phase is a simple orthodontic treatment representing the final therapy. Orthodontic and/or prosthodontic rehabilitation of dentition, in fact, is the ultimate step of the therapeutic scheme which allows long-lasting RESULTS.

Effect of alpha-difluoromethyl-ornithine on the expression and function of the epidermal growth factor receptor in human breast epithelial cells in culture.

We have previously shown that ornithine decarboxylase (ODC) overexpression enhances the transforming effects of HER-2neu and epidermal growth factor (EGF) in normal MCF-10A human breast epithelial cells. Our data suggest that such potentiation may be mediated by activation of the mitogen-activated protein kinase (MAPK) pathway and, possibly, STAT signalling. To further explore the interaction between the polyamine pathway and EGF/HER-2neu signalling in this system, we inhibited endogenous ODC activity with alpha-difluoromethylornithine (DFMO) and assessed the effects of this blockade on the expression of EGF receptors (EGFR) and HER-2neu as well as activation of downstream EGF target genes. We found that DFMO administration to MCF-10A cells increased EGF-R mRNA and protein levels in a dose-response fashion, while HER-2neu expression was not affected. The effect of DFMO was mediated through polyamine depletion since it could be reversed by exogenous putrescine administration. Our results also indicated that the increase in EGFR induced by DFMO was not a non-specific consequence of inhibition of cell proliferation. The upregulated EGFRs were functional since they could be phosphorylated by EGF and they were able to promote phosphorylation of downstream signalling molecules including ERK, STAT-3, and STAT-5. We propose that physiologic levels of ODC activity may be critical for regulation of a yet undefined signalling pathway, whose blockade by DFMO leads to a compensatory increase in functional EGFR.

Immunohistochemical detection of ornithine-decarboxylase in primary and metastatic human breast cancer specimens.

Increased ornithine decarboxylase (ODC) activity in human breast cancer specimens has recently been shown to be an independent adverse prognostic factor for recurrence and death. Biochemical measurement of ODC, however, is not practical for routine clinical use. Furthermore, it does not take into account the heterogeneous composition of human breast cancers which contain variable proportions of epithelial and stromal elements. Therefore, we developed an immunohistochemical method for ODC determination which can be applied to formalin-fixed, paraffin-embedded tissue sections. We report here our results in a series of 30 human breast cancer samples. ODC expression was detected most consistently in the malignant epithelial component of the tumors. Twenty-seven of 30 samples stained positive with intensities ranging from 1+ to 3+. The fraction of malignant epithelial cells expressing ODC varied among specimens between 10% and > 90%. When quantitated by H-SCORE, ODC expression was significantly higher in the malignant epithelial component than in normal appearing epithelial cells and stroma admixed within the tumor. Normal mammary tissue adjacent to the cancer was available for analysis in six cases. ODC expression was absent in two (while both cancers were positive) but present in four to a degree which was overall comparable to that observed in the corresponding tumors. We believe that this technique will be useful for future studies aimed at expanding our knowledge of the role of ODC and polyamines (PA) in breast cancer biology.

S-adenosylmethionine decarboxylase overexpression reduces invasiveness and tumorigenicity in nude mice of MCF-7 breast cancer cells.

To elucidate the role of S-adenosylmethionine decarboxylase (SAMDC) in breast cancer biology, we have generated SAMDC overexpressing MCF-7 breast cancer cells. SAMDC overexpression did not alter in a major way growth properties of MCF-7 cells in soft agar, either under basal conditions or in response to estrogen and antiestrogen administration. SAMDC-MCF-7 cells, on the other hand, exhibited a markedly reduced invasive ability in matrigel (p=0.013). Furthermore, they were less tumorigenic in nude mice. The odds for control clones to form tumors were 3.13 (C.1.1.2-8.2, p=0.0184) higher than those for SAMDC clones. The odds ratio were identical in the absence and in the presence of estradiol. In addition, the growth rate of established tumors was slower for SAMDC than for control clones. Overall, our results are consistent with the notion that these phenotypic changes induced by SAMDC overexpression are primarily mediated by suppression of cellular putrescine (and, possibly, spermidine) levels.

[Efficacy of 4 adhesive systems for amalgam. In vitro study]. / Efficacia di 4 sistemi adesivi per amalgama. Studio in vitro.

BACKGROUND: The aim of this research is to study the shear bond strength of 4 adhesive systems of the last generation: All-Bond 2 (AB2), Clearfil Liner Bond 2 (CL), Scotchbond MP plus (SBMP) and High Q Bond plus (HQB). According to the manufacturing company these products are suitable for amalgam adhesion to dentin. METHODS: Forty extracted human third molars have been ground to expose a flat dentin surface. The teeth were randomly assigned to 4 groups, and every group was treated with one of the adhesive system according to the manufacturer's instructions. Samples were then secured in a split Teflon mould, having a 6 mm diameter opening and a spherical amalgam was triturated and condensed onto the treated dentin surfaces. The amalgam cylinders have been exposed to a tensile bond test using a Universal Testing Machine (Instron 4500). ANOVA test has been used to the statistic study among groups. RESULTS: The study of the tensile mean range, showed that dentin shear bond strength values (MPa) for the adhesive systems tested were: 8.13 +/- 1.48 for AB2, 7.06 +/- 1.41 for SBMP, 4.2 +/- 1.06 for HQB, 3.04 +/- 0.68 for CL. The statistic test revealed significant differences among the 4 groups (p < 0.05). CONCLUSIONS: The bond strength mean values of amalgam adhesives are lower than the ones for composite resins, nevertheless dentin-enamel adhesive systems specific for amalgam have to be taken into consideration particularly in case of conservative restorations that need chemical retention as a support, when the mechanical one is not enough.

Alpha-difluoromethylornithine as treatment for metastatic breast cancer patients.

DFMO (alpha-difluoromethylornithine) is an oral irreversible inhibitor of ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis. DFMO has been shown to have antiproliferative effects against several human cancers, and some studies have suggested that DFMO may have pro-apoptotic and anti-invasive properties as well. DFMO is well tolerated with minimal toxicity but has been associated with ototoxicity with prolonged daily administration. We conducted a Phase I/II tolerability, pharmacokinetic, and efficacy study of high-dose DFMO in metastatic breast cancer patients. Twenty-one patients were treated with 4800 mg of DFMO p.o. three times a day for 14 days, followed by a 2-week drug holiday on a 28-day cycle. Urinary polyamine and blood DFMO levels were measured at multiple time points during therapy. High-dose DFMO was well tolerated, and no clinically significant ototoxicity was noted. No patient achieved an objective antitumor response; however, one patient with heavily pretreated liver metastases has achieved stable disease for 18 months to date on DFMO. Putrescine, spermine, and spermidine urinary levels were suppressed with DFMO treatment and remained low during the 2-week drug holiday. High-dose DFMO on a schedule of 2 weeks on treatment followed by 2 weeks off is well tolerated, is not associated with ototoxicity, and leads to sustained suppression of urinary polyamine levels. Although not an active cytotoxic agent for metastatic breast cancer, the intriguing prolonged growth arrest of liver metastases in one patient highlights the potential clinical growth inhibitory properties of DFMO. We believe that DFMO is worthy of study as adjuvant therapy in primary breast cancer patients and as a chemopreventive agent.

Hormonal approaches to the chemoprevention of endocrine-dependent tumors.

The estrogen dependency of human breast cancer has been successfully exploited in the treatment of early and advanced diseases and provides a unique opportunity for chemoprevention of this common malignancy. Preliminary results with the antiestrogens Tamoxifen and Raloxifene show an encouraging reduction in the incidence of breast cancer. Alternative approaches include the use of highly selective and non-toxic aromatase inhibitors and, in premenopausal women, the use of LHRH agonists in conjunction with the administration of small doses of estrogen and progesterone. The rationale for these chemopreventive strategies and their possible limitations are briefly discussed.

Cooperativity between the polyamine pathway and HER-2neu in transformation of human mammary epithelial cells in culture: role of the MAPK pathway.

Our experiments were designed to test the cooperativity between the polyamine pathway and HER-2neu in inducing transformation of human mammary epithelial cells in culture. Using the MCF-10A breast epithelial cell line, we observed that induction of overexpression of ornithine decarboxylase (ODC) (the first rate-limiting enzyme in polyamine biosynthesis) markedly potentiated the anchorage-independent growth stimulating effect of the beta2 isoform of neu differentiating factor (NDF) known to activate HER-2neu in MCF-10A cells. ODC overexpression, on the other hand, did not enhance growth in liquid culture, thus pointing to a specific effect on transformation rather than proliferation. ODC-overexpressing MCF-10A cells exhibited increased MAPK phosphorylation in response to administration of NDF and/or epidermal growth factor (EGF). In contrast, the phosphorylation of the members of the stress-activated protein kinase cascade p38 and SEK were not affected by ODC overexpression. Of note, in the absence of EGF and NDF, ODC overexpression failed to induce both clonogenicity and MAPK activation. These results suggest that increased polyamine biosynthetic activity critically interacts with HER-2neu in promoting human mammary cell transformation in culture and that the MAPK cascade is an important mediator of this interaction. If confirmed in future in vivo studies, our results may identify important new targets for the chemoprevention of human breast cancer.

Ornithine decarboxylase over-expression stimulates mitogen-activated protein kinase and anchorage-independent growth of human breast epithelial cells.

In these experiments we tested the hypothesis that constitutive activation of polyamine(PA) biosynthesis may contribute to mammary carcinogenesis. Spontaneously immortalized normal human MCF-10A breast epithelial cells were infected with the retroviral vector pLOSN containing a cDNA which codes for a truncated and more stable ornithine decarboxylase (ODC), the rate-limiting enzyme in PA synthesis. Upon chronic selective pressure with alpha-difluoromethyl-ornithine (DFMO) (an irreversible inhibitor of ODC), infected MCF-10A cells exhibited an approximately 250-fold increase in ODC activity, which persisted despite discontinuation of DFMO. ODC-over-expressing MCF-10A cells showed a modest decrease in S-adenosylmethionine decarboxylase and an increase in spermidine/spermineN1-acetyltransferase. Analysis of cellular PA profile revealed a selective accumulation of putrescine without alterations in spermidine and spermine contents. Lesser degrees of increased ODC activity were obtained reproducibly by re-exposing the cells to incremental small doses of DFMO. We observed a bell-shaped dose-related positive effect of ODC activity on clonogenicity in soft agar of MCF-10A cells. Since anchorage-dependent growth was actually reduced, such positive influence on this feature of transformation was not a non-specific consequence of a growth advantage provided by ODC over-expression. In addition, we observed a close parallelism between the dose-dependent effects of ODC expression on clonogenicity and activity of the ERK-2 kinase, a central element of the MAPK cascade. Our data demonstrate an interaction between PA and the MAPK signalling pathway and suggest that the latter may be involved in ODC-induced transformation of mammary epithelial cells.