[Effectiveness of strategies to increase adherence to colorectal cancer screening: a systematic review]. / Efectividad de estrategias para incrementar la adherencia al tamizaje de cáncer colorrectal: una revisión sistemática.

INTRODUCTION: Coverage for colorectal cancer screening in Argentina is very low. The objective of this review is to assess and synthesize the evidence on the effectiveness of strategies aimed at increasing adherence to colorectal cancer screening among healthcare personnel and the general population at average risk. METHODS: A review of systematic reviews (SRs) that evaluated the effectiveness of these strategies was conducted. Searches were performed in electronic databases, meta-search engines, the Cochrane Library, and through manual searching. Eligibility and inclusion criteria were applied, with assessment of the quality of the SRs using AMSTAR II and the certainty of evidence using the GRADE approach. Thematic synthesis was conducted based on the taxonomy of strategies proposed by Dougherty (patient/community-targeted, professionaltargeted, and other types of strategies). RESULTS: A total of 635 studies were identified, with 36 deemed eligible and 11 excluded due to insufficient quality, resulting in the inclusion of 10 SRs. A multiplicity of strategies with varying effectiveness were identified, with the majority targeting the population. Among these, education, self-testing with specimen collection at specific locations, and reminders stood out. For professionals, only education and reminders showed effectiveness. Combined strategies demonstrated greater effectiveness than isolated strategies. CONCLUSIONS: There is more evidence on strategies targeting the population than professionals. Combined strategies showed greater effectiveness, highlighting the need to explore barriers in both the population and professionals in each specific context in order to prioritize and combine those that have proven effective and would have a greater impact.

Introducción: En Argentina la cobertura al tamizaje de cáncer colorrectal (CCR) es muy baja. El objetivo de esta revisión fue relevar y sintetizar la evidencia sobre la efectividad de estrategias dirigidas a incrementar la adherencia al tamizaje de CCR del personal de salud y población con riesgo promedio. Métodos: Revisión de revisiones sistemáticas (RS) que evaluaron la efectividad de dichas estrategias. Búsqueda en bases de datos electrónicas, meta-buscadores, biblioteca Cochrane y búsqueda manual. Aplicación de criterios de elegibilidad e inclusión; con evaluación de la calidad de las RS a través del AMSTAR-II y la certeza de la evidencia por el método GRADE. Síntesis temática sobre la base de la taxonomía de estrategias propuesta por Dougherty (dirigidas al paciente/comunidad; a profesionales; otro tipo de estrategias). Resultados: Se identificaron 635 estudios; 36 fueron elegibles y 11 se descartaron por no contar con calidad suficiente, incluyéndose 10 RS. Se identificó una multiplicidad de estrategias de efectividad variada, la mayoría dirigida a la población. Entre estas, destacan la educación, el auto-test con recolección en lugares específicos y recordatorios. En el caso de profesionales, solo educación y recordatorios mostraron ser efectivas. La combinación de estrategias mostró tener mayor efectividad que las estrategias aisladas. Conclusiones: Es mayor la evidencia sobre estrategias dirigidas a la población que a profesionales. Las estrategias combinadas demostraron tener mayor efectividad, lo que destaca la necesidad de explorar, en cada contexto, las barreras en la población y en los profesionales para priorizar y combinar aquellas que demostraron ser efectivas y tendrían mayor impacto.

[Barriers and facilitators of colorectal cancer screening access]. / Barreras y facilitadores del acceso al tamizaje de cáncer colorrectal.

INTRODUCTION: Colorectal cancer (CRC) is a global health problem. In the public sector of Bahía Blanca, CRC screening is opportunistic, through the request of fecal occult blood test (FOBT). The objective of this study is to describe access to CRC screening for the population with exclusive public coverage residing in the programmatic area 2 of the city between 2019 and 2021, and to identify the barriers and facilitators that determine it. METHODS: The annual and cumulative usage rate was estimated based on the number of patients who requested FOBT. The barriers and facilitators were studied through 41 semi-structured individual interviews to healthcare staff from the area, the Municipal Hospital, Health Secretariat and users/non-users of the system. RESULTS: The cumulative usage rate of FOBT during the period was less than 5%. Among the perceived barriers to screening, we found: the difficulties in accessing more complex studies for patients with positive FOBT, the lack of population awareness and perception of CRC as a health problem, the low adherence of professionals to guidelines. The territoriality and link of health centers with the population, as well as the willingness of users and professionals to incorporate screening, emerge as facilitators. CONCLUSION: The identification of barriers and facilitators will allow the design of context-adapted strategies that will strengthen screening in the future.

Introducción: El cáncer colorrectal (CCR) es un problema de salud a nivel global. En el sector público de Bahía Blanca, el tamizaje de CCR es oportunista, por solicitud de sangre oculta en materia fecal (SOMF). El objetivo de este trabajo es describir el acceso al tamizaje de CCR de la población con cobertura pública exclusiva que reside en el área programática 2 de la ciudad entre 2019 y 2021, y relevar las barreras y facilitadores que lo determinan. Métodos: Se estimó la tasa de uso anual y acumulada de SOMF. Las barreras y facilitadores se relevaron a través de 41 entrevistas individuales semi-estructuradas al personal de salud del área programática, el Hospital Municipal, Secretaría de Salud y usuarios/no usuarios del sistema. Resultados: La tasa acumulada de uso de SOMF en el período fue 4.8%. Entre las barreras al tamizaje percibidas se destacan: la dificultad en el acceso a estudios de mayor complejidad para pacientes con SOMF+, el desconocimiento y falta de percepción del CCR como un problema de salud por parte de la población y la baja adherencia de los profesionales a los lineamientos. La territorialidad y el vínculo de los centros de salud con la población, y la predisposición de usuarios y profesionales a incorporar el tamizaje surgen como facilitadores del mismo. Conclusiones: El relevamiento de las barreras orientará el diseño de estrategias adaptadas al contexto que permitan en el futuro reforzar el tamizaje.

The Beta2-adrenergic agonist salbutamol synergizes with paclitaxel on cell proliferation and tumor growth in triple negative breast cancer models.

PURPOSE: Globally breast cancer accounts for 24.5% in incidence and 15.5% in cancer deaths in women. The triple-negative subtype lacks any specific therapy and is treated with chemotherapy, resulting in significant side-effects. We aimed to investigate if the dose of chemotherapeutic drugs could be diminished by co-administering it with the ß2-agonist salbutamol. METHODS: Cell proliferation was measured by thymidine incorporation; gene expression, by real-time PCR and protein phosphorylation by WB. Apoptosis was assessed by acridine orange / ethidium bromide and TUNEL tests. Public patient databases were consulted. Cells were inoculated to nude mice and their growth assessed. RESULTS: The ß2-agonist salbutamol synergizes in MDA-MB-231 cells in vitro with paclitaxel and doxorubicin on cell proliferation through ADRB2 receptors, while the ß-blocker propranolol does not. The expression of this receptor was assessed in patient databases and other cell lines. Triple negative samples had the lowest expression. Salbutamol and paclitaxel decreased MDA-MB-231 cell proliferation while their combination further inhibited it. The pathways involved were analyzed. When these cells were inoculated to nude mice, paclitaxel and salbutamol inhibited tumor growth. The combined effect was significantly greater. Paclitaxel increased the expression of MDR1 while salbutamol partially reversed this increase. CONCLUSION: While the effect of salbutamol was mainly on cell proliferation, suboptimal concentrations of paclitaxel provoked a very important enhancement of apoptosis. The latter enhanced transporter proteins as MDR1, whose expression were diminished by salbutamol. The expression of ADRB2 should be assessed in the biopsy or tumor to eventually select patients that could benefit from salbutamol repurposing.

Adrenergic receptors in breast cancer.

Breast cancer is the most diagnosed malignancy in women worldwide and in the majority of the countries. Breast cancers are classified on the expression of estrogen and progesterone receptor expression and overexpression of human epidermal growth factor receptor 2 (HER2) as luminal, HER2+ and triple negative breast cancer. The intrinsic molecular subtypes match this classification. Cancer diagnosis and treatment cause distress. In both acute and chronic stress, the secreted catecholamines adrenaline and noradrenaline trigger the "fight-or-flight" response. This chapter focuses on the actions of the ß2 and α2 adrenergic receptors in several models of breast cancer. The actions of these receptors depend on the model used to investigate them. The ß2-adrenergic receptors seem to exert a dual action. They can directly act on the epithelial cells inhibiting cell proliferation and migration/invasion and indirectly upon the immune microenvironment. The proportion of ß2 receptors in each compartment could, therefore, lean the scale to an inhibition or to an exacerbation of tumor growth, invasion and metastasis. All the work points to a beneficial or neutral action of ß-blockers on breast cancer. With respect to α2-adrenergic receptors, the investigation performed by our group suggest that the α2B and the α2C receptors are linked to enhanced cell proliferation and tumor growth acting through both the epithelial and the stromal (fibroblastic) compartments while α2A could be beneficial for patients. Some adrenergic compounds could be repurposed for breast cancer treatment due to their very low side effects and very well-known pharmacology.

Tyrosine phosphorylation differentially fine-tunes ionotropic and metabotropic responses of human α7 nicotinic acetylcholine receptor.

The α7 nicotinic acetylcholine receptor is involved in neurological, neurodegenerative, and inflammatory disorders. It operates both as a ligand-gated cationic channel and as a metabotropic receptor in neuronal and non-neuronal cells. As protein phosphorylation is an important cell function regulatory mechanism, deciphering how tyrosine phosphorylation modulates α7 dual ionotropic/metabotropic molecular function is required for understanding its integral role in physiological and pathological processes. α7 single-channel activity elicited by ACh appears as brief isolated openings and less often as episodes of few openings in quick succession. The reduction of phosphorylation by tyrosine kinase inhibition increases the duration and frequency of activation episodes, whereas the inhibition of phosphatases has the opposite effect. Removal of two tyrosine residues at the α7 intracellular domain recapitulates the effects mediated by tyrosine kinase inhibition. The tyrosine-free mutant receptor shows longer duration-activation episodes, reduced desensitization rate and significantly faster recovery from desensitization, indicating that phosphorylation decreases α7 channel activity by favoring the desensitized state. However, the mutant receptor is incapable of triggering ERK1/2 phosphorylation in response to the α7-agonist. Thus, while tyrosine phosphorylation is absolutely required for α7-triggered ERK pathway, it negatively modulates α7 ionotropic activity. Overall, phosphorylation/dephosphorylation events fine-tune the integrated cell response mediated by α7 activation, thus having a broad impact on α7 cholinergic signaling.

Agonist Effects of Propranolol on Non-Tumor Human Breast Cells.

The ß-blocker propranolol (PROP) has been proposed as a repurposed treatment for breast cancer. The similarity of action between ß-agonists and antagonists found on breast cells encouraged us to compare PROP and isoproterenol (ISO, agonist) signaling pathways on a human breast cell line. Cell proliferation was measured by cell counting and DNA-synthesis. Cell adhesion was measured counting the cells that remained adhered to the plastic after different treatments. Changes in actin cytoskeleton were observed by fluorescence staining and Western Blot. ISO and PROP caused a diminution of cell proliferation and an increase of cell adhesion, reverted by the pure ß-antagonist ICI-118551. ISO and PROP induced a reorganization of actin cytoskeleton increasing F-actin, p-COFILIN and p-LIMK. While ISO elicited a marked enhancement of cAMP concentrations and an increase of vasodilator-stimulated phosphoprotein (VASP) and cAMP response element-binding protein (CREB) phosphorylation, PROP did not. Clathrin-mediated endocytosis inhibition or ß-arrestin1 dominant-negative mutant abrogated PROP-induced cell adhesion and COFILIN phosphorylation. The fact that PROP has been proposed as an adjuvant drug for breast cancer makes it necessary to determine the specific action of PROP in breast models. These results provide an explanation for the discrepancies observed between experimental results and clinical evidence.

Prognostic significance of α- and ß2-adrenoceptor gene expression in breast cancer patients.

AIMS: Breast cancer is the most frequently diagnosed and leading cause of cancer death among women worldwide. It was classified within molecular intrinsic subtypes: luminal A, luminal B, human epidermal growth factor receptor 2-enriched and basal-like. Epinephrine and norepinephrine, released during stress, bind to adrenoceptors. α2 -adrenoceptors are encoded by the ADRA2A, ADRA2B and ADRA2C genes and ß2 by ADRB2. METHODS: We compiled several publicly available Affymetrix gene expression datasets, obtaining a large cohort of 1924 patients with distant metastasis-free survival (DMFS) data and evaluated the association between adrenoceptor expression, clinicopathological markers and outcome. RESULTS: ADRA2A high expressing tumours also expressed hormone receptors and presented diminished tumour size, grade and not compromised lymph nodes. ADRB2 high expression was found in smaller, low grade, oestrogen receptor-positive tumours. Both were significantly associated with the absence of metastasis. High expression of ADRA2C was positively associated with increased tumour size and metastatic relapse. We observed a significant increase in DMFS of patients with high ADRA2A (hazard ratio 0.54, 95% CI 0.45-0.65, P < .001) and ADRB2 (0.77, 0.64-0.93, P = .006) expression and a decrease with ADRA2C high expression (1.45, 1.16-1.81, P = .001). For patients with luminal tumours, ADRA2A was the only factor that retained its significance as an independent predictor of DMFS while ADRA2C expression was an independent predictor for worse prognosis in basal-like tumours. CONCLUSIONS: We herein provide new insight for a potential role of ADRA2A and ADRA2C in breast cancer. In low- and medium-income countries, their incorporation to routine immunohistochemistry analysis of biopsies or tumour samples, could provide additional low-cost prognostic factors.

A human-specific, truncated α7 nicotinic receptor subunit assembles with full-length α7 and forms functional receptors with different stoichiometries.

The cholinergic α7 nicotinic receptor gene, CHRNA7, encodes a subunit that forms the homopentameric α7 receptor, involved in learning and memory. In humans, exons 5-10 in CHRNA7 are duplicated and fused to the FAM7A genetic element, giving rise to the hybrid gene CHRFAM7A Its product, dupα7, is a truncated subunit lacking part of the N-terminal extracellular ligand-binding domain and is associated with neurological disorders, including schizophrenia, and immunomodulation. We combined dupα7 expression on mammalian cells with patch clamp recordings to understand its functional role. Transfected cells expressed dupα7 protein, but they exhibited neither surface binding of the α7 antagonist α-bungarotoxin nor responses to acetylcholine (ACh) or to an allosteric agonist that binds to the conserved transmembrane region. To determine whether dupα7 assembles with α7, we generated receptors comprising α7 and dupα7 subunits, one of which was tagged with conductance substitutions that report subunit stoichiometry and monitored ACh-elicited channel openings in the presence of a positive allosteric α7 modulator. We found that α7 and dupα7 subunits co-assemble into functional heteromeric receptors, which require at least two α7 subunits for channel opening, and that dupα7's presence in the pentameric arrangement does not affect the duration of the potentiated events compared with that of α7. Using an α7 subunit mutant, we found that activation of (α7)2(dupα7)3 receptors occurs through ACh binding at the α7/α7 interfacial binding site. Our study contributes to the understanding of the modulation of α7 function by the human specific, duplicated subunit, associated with human disorders.

The ß 2-Adrenergic Agonist Salbutamol Inhibits Migration, Invasion and Metastasis of the Human Breast Cancer MDA-MB- 231 Cell Line.

BACKGROUND: Breast cancer is the most diagnosed and the major cause of cancer death in women worldwide. Metastasis is the main cause of these deaths. The metastatic cascade involves multiple steps and it has been described that adrenergic receptors can modulate this process at multiple levels. However, ß -adrenergic action in breast cancer is controversial. We have previously shown that ß-adrenergic agonists inhibit cell proliferation and tumor growth of numerous breast cancer models. OBJECTIVE: The purpose of the present investigation was to evaluate adrenergic effect in parameters related to tumor progression (migration, invasion and metastases) in two human breast cancer cell lines. METHODS: Migration was assessed in IBH-6 and MDA-MB-231 cells by time-lapse videomicroscopy and modified Boyden chambers. Invasion was evaluated by Transwells coated with Matrigel and expression of pro-metastatic genes was determined by RT-qPCR. Experimental metastases studies were performed by injection of the cells in the tail vein of NSG immuno-deficient mice. RESULTS: In both cell lines, salbutamol (ß2-agonist) and propranolol (ß-blocker) significantly diminished cell migration while epinephrine exerted opposite effects. Moreover, salbutamol inhibited invasion of both breast cancer cell lines and enhanced adhesion to extracellular matrix. Salbutamol treatment was also able to decrease the expression of pro-metastatic genes in MDA-MB-231 cells. Finally, this compound decreased the number and size of MDA-MB-231 lung experimental metastases in NSG immuno- deficient mice. No effect on the establishment of IBH-6 metastases was observed. CONCLUSION: Our results suggest that salbutamol could be an effective adjuvant drug for the treatment of metastatic breast cancer.

A Novel Effect of ß-Adrenergic Receptor on Mammary Branching Morphogenesis and its Possible Implications in Breast Cancer.

Understanding the mechanisms that govern normal mammary gland development is crucial to the comprehension of breast cancer etiology. ß-adrenergic receptors (ß-AR) are targets of endogenous catecholamines such as epinephrine that have gained importance in the context of cancer biology. Differences in ß2-AR expression levels may be responsible for the effects of epinephrine on tumor vs non-tumorigenic breast cell lines, the latter expressing higher levels of ß2-AR. To study regulation of the breast cell phenotype by ß2-AR, we over-expressed ß2-AR in MCF-7 breast cancer cells and knocked-down the receptor in non-tumorigenic MCF-10A breast cells. In MCF-10A cells having knocked-down ß2-AR, epinephrine increased cell proliferation and migration, similar to the response by tumor cells. In contrast, in MCF-7 cells overexpressing the ß2-AR, epinephrine decreased cell proliferation and migration and increased adhesion, mimicking the response of the non-tumorigenic MCF-10A cells, thus underscoring that ß2-AR expression level is a key player in cell behavior. ß-adrenergic stimulation with isoproterenol induced differentiation of breast cells growing in 3-dimension cell culture, and also the branching of murine mammary epithelium in vivo. Branching induced by isoproterenol was abolished in fulvestrant or tamoxifen-treated mice, demonstrating that the effect of ß-adrenergic stimulation on branching is dependent on the estrogen receptor (ER). An ER-independent effect of isoproterenol on lumen architecture was nonetheless found. Isoproterenol significantly increased the expression of ERα, Ephrine-B1 and fibroblast growth factors in the mammary glands of mice, and in MCF-10A cells. In a poorly differentiated murine ductal carcinoma, isoproterenol also decreased tumor growth and induced tumor differentiation. This study highlights that catecholamines, through ß-AR activation, seem to be involved in mammary gland development, inducing mature duct formation. Additionally, this differentiating effect could be resourceful in a breast tumor context.

Differential ß2-adrenergic receptor expression defines the phenotype of non-tumorigenic and malignant human breast cell lines.

Breast cancer is the most frequent malignancy in women. Several reports demonstrated that adrenergic receptors (ARs) are involved in breast cancer. Here we observed that epinephrine (Epi), an endogenous AR agonist, caused opposite effects in non-tumorigenic (MCF-10A and HBL-100) and tumor cells (MCF-7 and MDA-MB-231). Thus, Epi, in non-tumor breast cells, as well as isoproterenol (ß-agonist), in all cell lines, maintained a benign phenotype, decreasing cell proliferation and migration, and stimulating cell adhesion. ß-AR expression and cAMP levels were higher in MCF-10A than in MCF-7 cells. ß2-AR knock-down caused a significant increase of cell proliferation and migration, and a decrease of cell adhesion both in basal and in Iso-stimulated conditions. Coincidently, ß2-AR over-expression induced a significant decrease of cell proliferation and migration, and an increase of cell adhesion. Therefore, ß2-AR is implied in cell phenotype and its agonists or antagonists could eventually complement cancer therapy.

Multidrug resistance protein 4/ ATP binding cassette transporter 4: a new potential therapeutic target for acute myeloid leukemia.

Less than a third of adults patients with acute myeloid leukemia (AML) are cured by current treatments, emphasizing the need for new approaches to therapy. We previously demonstrated that besides playing a role in drug-resistant leukemia cell lines, multidrug resistance protein 4 (MRP4/ABCC4) regulates leukemia cell proliferation and differentiation through the endogenous MRP4/ABCC4 substrate, cAMP. Here, we studied the role of MRP4/ABCC4 in tumor progression in a mouse xenograft model and in leukemic stem cells (LSCs) differentiation. We found a decrease in the mitotic index and an increase in the apoptotic index associated with the inhibition of tumor growth when mice were treated with rolipram (PDE4 inhibitor) and/or probenecid (MRPs inhibitor). Genetic silencing and pharmacologic inhibition of MRP4 reduced tumor growth. Furthermore, MRP4 knockdown induced cell cycle arrest and apoptosis in vivo. Interestingly, when LSC population was isolated, we observed that increased cAMP levels and MRP4/ABCC4 blockade resulted in LSCs differentiation. Taken together, our findings show that MRP4/ABCC4 has a relevant role in tumor growth and apoptosis and in the eradication of LSCs, providing the basis for a novel promising target in AML therapy.

Dosage-dependent regulation of cell proliferation and adhesion through dual ß2-adrenergic receptor/cAMP signals.

The role of ß-adrenergic receptors (ß-ARs) remains controversial in normal and tumor breast. Herein we explore the cAMP signaling involved in ß-AR-dependent control of proliferation and adhesion of nontumor human breast cell line MCF-10A. Low concentrations of a ß-agonist, isoproterenol (ISO), promote cell adhesion (87.5% cells remaining adherent to the plastic dishes following specific detachment vs. 35.0% in control, P<0.001), while increasing concentrations further engages an additional 36% inhibition of Erk1/2 phosphorylation (p-Erk1/2)-dependent cell proliferation (P<0.01). Isoproterenol dose response on cell adhesion was fitted to a 2-site curve (EC50(1): 16.5±11.5 fM, EC50(2): 4.08±3.09 nM), while ISO significantly inhibited p-Erk1/2 according to a 1-site model (EC50: 0.25±0.13 nM). Using ß-AR-selective agonist/antagonists and cAMP analogs/inhibitors, we identified a dosage-dependent signaling in which low ISO concentrations target a ß2-AR population localized in raft microdomains and stimulate a Gs/cAMP/Epac/adhesion-signaling module, while higher concentrations engage a concomitant activation of another ß2-AR population outside rafts and inhibit the proliferation by a Gs/cAMP/PKA-dependent signaling module. Our data provide a new molecular basis for the dose-dependent switch of ß-AR signaling. This study also sheds light on a new cAMP pathway core mechanism with a single receptor triggering dual cAMP signaling controlled by PKA or Epac but with different cellular outputs.

Human adipose tissue from normal and tumoral breast regulates the behavior of mammary epithelial cells.

INTRODUCTION: Stromal-epithelial interactions mediate both breast development and breast cancer progression. In the present work, we evaluated the effects of conditioned media (CMs) of human adipose tissue explants from normal (hATN) and tumor (hATT) breast on proliferation, adhesion, migration and metalloproteases activity on tumor (MCF-7 and IBH-7) and non-tumor (MCF-10A) human breast epithelial cell lines. MATERIALS AND METHODS: Human adipose tissues were obtained from patients and the conditioned medium from hATN and hATT collected after 24 h of incubation. MCF-10A, MCF-7 and IBH-7 cells were grown and incubated with CMs and proliferation and adhesion, as well as migration ability and metalloprotease activity, of epithelial cells after exposing cell cultures to hATN- or hATT-CMs were quantified. The statistical significance between different experimental conditions was evaluated by one-way ANOVA. Tukey's post hoc tests were performed. RESULTS: Tumor and non-tumor breast epithelial cells significantly increased their proliferation activity after 24 h of treatment with hATT-CMs compared to control-CMs. Furthermore, cellular adhesion of these two tumor cell lines was significantly lower with hATT-CMs than with hATN-CMs. Therefore, hATT-CMs seem to induce significantly lower expression or less activity of the components involved in cellular adhesion than hATN-CMs. In addition, hATT-CMs induced pro-MMP-9 and MMP-9 activity and increased the migration of MCF-7 and IBH-7 cells compared to hATN-CMs. CONCLUSIONS: We conclude that the microenvironment of the tumor interacts in a dynamic way with the mutated epithelium. This evidence leads to the possibility to modify the tumor behavior/phenotype through the regulation or modification of its microenvironment. We developed a model in which we obtained CMs from adipose tissue explants completely, either from normal or tumor breast. In this way, we studied the contribution of soluble factors independently of the possible effects of direct cell contact.

α(2)-Adrenoceptors enhance cell proliferation and mammary tumor growth acting through both the stroma and the tumor cells.

We have previously described enhanced human breast cancer cell proliferation and mouse mammary tumor growth induced by α(2)-adrenoceptor (α(2)-AR) expression in epithelial cells. The aim of the present work was to assess if stromal fibroblasts can contribute to this effect. α(2)-AR expression was assessed by immunocytochemistry and immunohistochemistry, cell proliferation by [(3)H]-Thymidine incorporation and tumor growth by measuring with caliper. All tested mouse and human fibroblasts expressed at least two α(2)-AR subtypes and α(2)-adrenergic agonists enhanced fibroblast proliferation. In vivo, the α(2)-adrenergic agonist clonidine significantly enhanced tumor growth. The α(2)-adrenergic antagonist rauwolscine reversed this effect, but when administered alone, significantly inhibited tumor growth. Clonidine significantly stimulated cell proliferation in the epithelial-enriched fraction, the cancer associated fibroblast-enriched fraction and the co-culture of both fractions in primary cultures from both tumors (IBH-4 and IBH-6). Rauwolscine reversed clonidine stimulation in every fraction. However, when incubated alone, the inhibitory effect was observed in fractions from IBH-4 tumors but not from IBH-6 tumors. These experiments show that fibroblasts from tumor stroma are also influenced by α(2)-adrenergic compounds through the α(2)-ARs expressed in these cells. Moreover, the α(2)-adrenergic antagonist rauwolscine could eventually block in both epithelial and stromal cells, the mitogenic effect of catecholamines released during stress, providing a potential additional treatment for breast cancer patients. Chemists synthesizing adrenergic compounds should consider their action in breast cancer patients.

Might adrenergic alpha2C-agonists/alpha2A-antagonists become novel therapeutic tools for pain treatment with morphine?

The imidazoline nucleus linked in position 2 via an oxyethylene bridge to a phenyl ring carrying an ortho substituent of moderate steric bulk provided alpha(2)-adrenergic (AR) ligands endowed with significant alpha(2C)-agonism/alpha(2A)-antagonism. Similar behavior was displayed by cirazoline (12). For their positive morphine analgesia modulation (due to alpha(2C)-AR stimulation) and sedation overcoming (due to alpha(2A)-AR antagonism), 8 and 11 might be useful as adjuvant agents in the management of pain with morphine.

Novel human breast cancer cell lines IBH-4, IBH-6, and IBH-7 growing in nude mice.

Breast cancer is the most frequent cancer in women. However, in vivo hormone receptor positive and metastatic models are scarce. The aim of the present manuscript was to assess if the novel steroid receptor positive human cell lines IBH-4, IBH-6, and IBH-7 developed in our laboratory from primary infiltrant ductal carcinomas are good models to study in vivo human breast cancer. Cell lines or tumors were inoculated to nude mice in the presence or absence of hormone supplementation. Growth was analyzed by ANOVA followed by Tukey-Kramer's test. Steroid hormone expression was assessed by immunohistochemistry and Western blotting. The histology of the tumors was analyzed. IBH-4 and IBH-6 cells were inoculated to nude mice and 100% of the injected mice developed tumors in the presence or absence of hormone treatment, although tamoxifen inhibited growth. IBH-4 and IBH-6 cell lines in vivo gave rise to poorly differentiated carcinomas with areas of solid growth and sarcomatoid areas showing no morphological signs of epithelial differentiation. Distinct features of malignancy were observed. IBH-7 tumors in animals receiving estradiol were semi-differentiated adenocarcinomas. IBH-7 cells grew only in the presence of estradiol, but even with hormone addition, the tumor take was 20%. These tumors metastasized to the uterus and lung and vascular tumor emboli were evident. IBH-7 tumors were invasive and able to break through the peritoneum. As a conclusion, IBH-4 and IBH-6 are good models for studying tumor progression, whereas IBH-7 is a good model for tumor take, being metastatic and strictly estrogen-dependent.

Human breast cell lines exhibit functional alpha2-adrenoceptors.

Adrenergic compounds (epinephrine and norepinephrine) are the most important hormones released during stress. Several different receptors are associated with their action in different tissues. However, alpha(2)-adrenoceptors have not yet been described in either normal or tumour human breast tissue. The aim of this work was to describe and characterize these receptors in several tumour and non-tumour human cell lines. The expression of alpha(2)-adrenoceptors was analyzed at the RNA (RT-PCR) and protein ([(3)H]-rauwolscine binding and immunocytochemistry) levels in different human breast cell lines, and the biological activity assessed by [(3)H]-thymidine incorporation. The cancer IBH-6, IBH-7 and MCF-7 and the non-tumour HBL-100 cells line, expressed both alpha(2B)- and alpha(2C)-adrenoceptor-subtypes. A single subtype was expressed in malignant HS-578T (alpha(2A)) and MDA-MB-231 and non-tumour MCF-10A cells (alpha(2B)). All cell lines exhibited significant binding for the specific antagonist [(3)H]-rauwolscine. The alpha-, alpha(2)-, and the alpha(1)-compounds with known affinity for alpha(2)-adrenoceptors, including epinephrine, norepinephrine, yohimbine, clonidine, rauwolscine and prazosin, competed significantly with binding in MCF-7 cells. In addition, IBH-6, IBH-7 and MCF-7 cells showed significant staining with specific antibodies against alpha(2B)- and alpha(2C)-adrenoceptor-subtypes, when tested by immunocytochemistry. In all cell lines, the specific agonist clonidine or oxymetazoline stimulated [(3)H]-thymidine incorporation. EC(50) values were in the range of 20-50 fM for IBH-6, IBH-7, and HS-578T; 0.14 pM for MCF-7; 2-82 pM for HBL-100 and MCF-10A cells, and a biphasic behaviour with a maximum value at 38.0 pM, was observed for MDA-MB-231 cells. The specific alpha(2)-adrenergic antagonist rauwolscine always reversed this stimulation at 0.1 nM. In conclusion, this study describes for the first time, the presence of alpha(2)-adrenoceptors in human epithelial breast cell lines. Moreover, activation of these receptors was associated with an enhancement of cell proliferation.