Intermediate Ca2+-Sensitive K+ Channels are Necessary for Prolactin-Induced Proliferation in Breast Cancer Cells

Prolactin (PRL) is a polypeptidic hormone which acts both systemically and locally to cause lactation by interacting with the PRL receptor, a Janus kinase (JAK2)-coupled cytokine receptor family member. Several studies have reported that serum PRL level elevation is associated with an increased risk for breast cancer, and evidence has suggested that PRL is one actor in the pathogenesis and progression of this cancer. We previously reported the involvement of hIKCa1 in breast cell cycle progression and cell proliferation. However, mechanisms by which PRL cooperates with these channels to modulate breast epithelial cell proliferation remain unknown. Our results showed that, in the MCF-7 breast cancer cell line, PRL increased hIKCa1 current density. These channels were functional and regulated the resting membrane potential. The PRL effects were inhibited by TRAM-34 and clotrimazole, the most used hIKCa1 blockers. Moreover, PRL increased proliferation in a dose-dependent manner without overexpressing hIKCa1. To determine whether PRL-induced proliferation and hIKCa1 activity involved the JAK2 pathway, we used pharmacological JAK2 inhibitors (AG490 and JAK inhibitor I). Indeed, PRL-induced JAK2 phosphorylation was required for both cell proliferation and hIKCa1 activity. In the presence of either hIKCa1 blockers or siRNA-hIKCa1, PRL failed to increase cell proliferation and hIKCa1 activity. Taken together, our results demonstrate that PRL plays a role in breast cancer cell proliferation by increasing hIKCa1 activity through the JAK2 signaling pathway.     

Associations of rs1883832 and rs4810485 polymorphisms of CD40 gene with myocardial infarction in the Tunisian population

Context: Cluster of differentiation 40 (CD40), and its ligand CD40L, are major co-stimulatory molecules whose interactions are important in both cellular and humoral immunity, and has been suggested to play a role in the pathogenesis of acute coronary syndrome.

Objective: The aim of this study was to examine the association of CD40 polymorphisms (-1?C>T (rs1883832) and 945G>T (rs4810485)) and myocardial infarction (MI), and to test the association of CD40 gene haplotypes with MI in Tunisians.

Materials and methods: Three hundred and fifty MI patients and 301 apparently healthy controls were included in the study. The polymorphisms of CD40 were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results: There were significant differences in the genotype and allele frequencies of CD40 gene -1?C>T (rs1883832) polymorphism between cases and controls. Stratifying according to gender, the association between the TT genotype and MI was statistically significant in males, only. Haplotype analysis revealed that the C-T and T-G haplotypes were associated with an increased risk of MI (p?=?0.012 and p?<?0.001, respectively).

Conclusions: Our work showed a significant association between the -1?C>T (rs1883832) polymorphism of the CD40 gene and MI in the Tunisians.     

Do Parents Meet Adolescents’ Monitoring Standards? Examination of the Impact on Teen Risk Disclosure and Behaviors if They Don’t

In this study, we examined how adolescents compare monitoring efforts by their parents to those of a "good parent" standard and assessed the impact of these comparisons on adolescent self-disclosure and risk behavior and their perceptions of their parents'' monitoring knowledge. Survey responses from 519 adolescents (12–17 years) at baseline of a larger, longitudinal study examining parental monitoring and adolescent risk were examined. Adolescents’ “good parent comparisons” differed greatly by monitoring areas (e.g., telephone use, health, money); however, between 5.5% and 25.8% of adolescents believed their parents needed to monitor their activities more than they currently were monitoring. Alternatively, between 8.5% and 23.8% of adolescents believed their parents needed to monitor their activities less often. These perceptions significantly distinguished adolescents in terms of their level of disclosure, perceived monitoring knowledge, and risk involvement. Adolescents who viewed their parents as needing to monitor more were less likely to disclose information to their parents (p<.001), less likely to perceive their parents as having greater monitoring knowledge (p<.001), and more likely to be involved in a risk behaviors (p<.001) than adolescents who perceived their parents needed no change. Adolescent disclosure to a parent is a powerful predictor of adolescent risk and poor health outcomes. These findings demonstrate that adolescents'' comparisons of their parents'' monitoring efforts can predict differences in adolescent disclosure and future risk. Obtaining adolescent "good parent" comparisons may successfully identify intervention opportunities with the adolescent and parent by noting the areas of need and direction of monitoring improvement.     

Prevalence and Trends of Staphylococcus aureus Bacteraemia in Hospitalized Patients in South Africa, 2010 to 2012: Laboratory-Based Surveillance Mapping of Antimicrobial Resistance and Molecular Epidemiology

Introduction

We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends and molecular epidemiology trends of S. aureus bacteraemia (SAB).

Methods

Thirteen academic centres in South Africa were included from June 2010 until July 2012. S. aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR using the LightCycler 480 II was done for mecA and nuc. SCCmec and spa-typing were finalized with conventional PCR. We selected one isolate per common spa type per province for multilocus sequence typing (MLST).

Results

S. aureus from 2709 patients were included, and 1231 (46%) were resistant to methicillin, with a significant decline over the three-year period (p-value = 0.003). Geographical distribution of MRSA was significantly higher in Gauteng compared to the other provinces (P<0.001). Children <5 years were significantly associated with MRSA with higher rates compared to all other age groups (P = 0.01). The most prevalent SCCmec type was SCCmec type III (531 [41%]) followed by type IV (402 [31%]). Spa-typing discovered 47 different spa-types. The five (87%) most common spa-types were t037, t1257, t045, t064 and t012. Based on MLST, the commonest was ST612 clonal complex (CC8) (n = 7) followed by ST5 (CC5) (n = 4), ST36 (CC30) (n = 4) and ST239 (CC8) (n = 3).

Conclusions

MRSA rate is high in South Africa. Majority of the isolates were classified as SCCmec type III (41%) and type IV (31%), which are typically associated with hospital and community- acquired infections, respectively. Overall, this study reveals the presence of a variety of hospital-acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257. Monitoring trends in resistance and molecular typing is recommended to detect changing epidemiological trends in AMR patterns of SAB.     

Down‐regulation of Orai3 arrests cell‐cycle progression and induces apoptosis in breast cancer cells but not in normal breast epithelial cells

Breast cancer (BC) is the leading cancer in the world in terms of incidence and mortality in women. However, the mechanism by which BC develops remains largely unknown. The increase in cytosolic free Ca²⁺ can result in different physiological changes including cell growth and death. Orai isoforms are highly Ca²⁺ selective channels. In the present study, we analyzed Orai3 expression in normal and cancerous breast tissue samples, and its role in MCF‐7 BC and normal MCF‐10A mammary epithelial cell lines. We found that the expression of Orai3 mRNAs was higher in BC tissues and MCF‐7 cells than in normal tissues and MCF‐10A cells. Down‐regulation of Orai3 by siRNA inhibited MCF‐7 cell proliferation and arrested cell cycle at G1 phase. This phenomenon is associated with a reduction in CDKs 4/2 (cyclin‐dependent kinases) and cyclins E and D1 expression and an accumulation of p21^Waf1/Cip1 (a cyclin‐dependent kinase inhibitor) and p53 (a tumor‐suppressing protein). Orai3 was also involved in MCF‐7 cell survival. Furthermore, Orai3 mediated Ca²⁺ entry and contributed to intracellular calcium concentration ([Ca²⁺]_i). In MCF‐10A cells, silencing Orai3 failed to modify [Ca²⁺]_i, cell proliferation, cell‐cycle progression, cyclins (D1, E), CDKs (4, 2), and p21^Waf1/Cip1 expression. Our results provide strong evidence for a significant effect of Orai3 on BC cell growth in vitro and show that this effect is associated with the induction of cell cycle and apoptosis resistance. Our study highlights a possible role of Orai3 as therapeutic target in BC therapy. J. Cell. Physiol. 226: 542–551, 2011. © 2010 Wiley‐Liss, Inc.     

Roles of BdUNICULME4 and BdLAXATUM‐A in the non‐domesticated grass Brachypodium distachyon

In cultivated grasses, tillering, spike architecture and seed shattering represent major agronomical traits. In barley, maize and rice, the NOOT‐BOP‐COCH‐LIKE (NBCL) genes play important roles in development, especially in ligule development, tillering and flower identity. However, compared with dicots, the role of grass NBCL genes is underinvestigated. To better understand the role of grass NBCLs and to overcome any effects of domestication that might conceal their original functions, we studied TILLING nbcl mutants in the non‐domesticated grass Brachypodium distachyon. In B. distachyon, the NBCL genes BdUNICULME4 (CUL4) and BdLAXATUM‐A (LAXA) are orthologous, respectively, to the barley HvUniculme4 and HvLaxatum‐a, to the maize Zmtassels replace upper ears1 and Zmtassels replace upper ears2 and to the rice OsBLADE‐ON‐PETIOLE1 and OsBLADE‐ON‐PETIOLE2/3. In B. distachyon, our reverse genetics study shows that CUL4 is not essential for the establishment of the blade–sheath boundary but is necessary for the development of the ligule and auricles. We report that CUL4 also exerts a positive role in tillering and a negative role in spikelet meristem activity. On the other hand, we demonstrate that LAXA plays a negative role in tillering, positively participates in spikelet development and contributes to the control of floral organ number and identity. In this work, we functionally characterized two new NBCL genes in a context of non‐domesticated grass and highlighted original roles for grass NBCL genes that are related to important agronomical traits.     

First characterization of congenital myasthenic syndrome type 5 in North Africa

Molecular Biology Reports - Congenital myasthenic syndromes (CMS) are associated with defects in the structure and the function of neuromuscular junctions. These rare disorders can result from...     

Activation of the calcium-sensing receptor by high calcium induced breast cancer cell proliferation and TRPC1 cation channel over-expression potentially through EGFR pathways

The calcium sensing receptor (CaR) is a G-protein-coupled receptor that is activated by extracellular calcium ([Ca²⁺]_o). In MCF-7 human breast cancer cells, we previously reported that treatment with [Ca²⁺]_o for 24 h leads to an over-expression of the Transient Receptor Potential Canonical 1 (TRPC1) cation channel and cell proliferation. Both involve the extracellular signal-regulated Kinases 1 & 2 (ERK1/2). MCF-7 also expressed epidermal growth factor receptor (EGFR) which is involved in cell proliferation through ERK1/2. Therefore, we investigated the cross-talk between CaR and EGFR in mediating ERK1/2 phosphorylation, TRPC1 over-expression and cell proliferation. Our data show that both high [Ca²⁺]_o and EGF phosphorylate ERK1/2. Furthermore, inhibition of EGFR kinase and matrix metalloproteinases (MMPs) reduced the overall effects mediated by [Ca²⁺]_o such as activation of ERK1/2, expression of TRPC1 and cell proliferation. They indicate the important role of the CaR-EGFR-ERK axis in transmitting mitogenic signals generated by high [Ca²⁺]_o in MCF-7 cells.     

Antibacterial and antifungal activities of teucrium royleanum (Labiatea)

The crude methanolic extract and subsequent fractions of Teucrium royleanum (Labiatea) were screened for antibacterial and antifungal activities. Against tested pathogens, crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities. Highest antibacterial activity was displayed by the ethyl acetate fraction against S. typhi (100%), against E.coli (76.7%) and against P. aerugenosa (70.8%) followed by the chloroform fraction against S. typhi (85.7%). Similarly, the crude extract and its subsequent fractions showed mild to excellent activities in the antifungal bioassay with maximum antifungal activity against M. canis (87%) by the chloroform fraction followed by the ethyl acetate (71%) and n-butanol (70%) fractions.