Autophagy-regulating microRNAs: two-sided coin in the therapies of breast cancer.

Despite recent advances in the treatment of breast cancer (BC), it still remains as a prevalent and deadly cancer in the world. Given that BC is a heterogeneous disease, it is necessary to clarify molecular mechanisms in tumor cells to improve various therapy outcomes and overcome therapy resistance. Autophagy represents one of the most important intracellular degradation pathways involved in diverse biological processes and plays an important bi-directional role in tumor formation and progression. Among the several mechanisms that affect autophagy, microRNAs (miRNAs) play a crucial role as gene regulators. Several in vivo and in vitro studies have reported multiple miRNAs regulating autophagy in BC that affect tumor initiation, progression, and response to various therapies. In the present review, we highlighted the mechanisms through which miRNAs regulate autophagy in BC and their potential use as therapeutic targets.

IL-4 induces the formation of multinucleated giant cells and expression of ß5 integrin in central giant cell lesion.

BACKGROUND: It is now well established that IL-4 has a central role in the development of monocytes to multinucleated giant cells (MGCs) by inducing the expression of integrins on the surface of monocytes. The aim of this study was to investigate the potential role of IL-4 in induction of ß5 integrin expression in the peripheral blood samples of patients with giant cell granuloma. MATERIAL AND METHODS: Monocytes were isolated from peripheral blood samples of patients with central giant cell granuloma (CGCG) and healthy controls using human Monocyte Isolation Kit II. Isolated monocytes were then cultured in the absence or presence of IL-4 (10 and 20 ng/mL), and following RNA extraction and cDNA synthesis, Real-time PCR was performed to determine the level of ß5 integrin expression. The formation of CGCGs and morphological analyses were done under light microscopy. For confirmation of CGCGs, immunocytochemistry technique was also carried out by anti-RANK (receptor-activator of NF-κB ligand) antibody. RESULTS: In both patient and control groups, ß5 levels were significantly enhanced by increasing the IL-4 dose from 10 to 20 ng/mL. In addition, these differences were significant between patient and control groups without IL-4 treatment. On the other hand, the number of cells which expressed RANK and therefore the number of giant cells were significantly higher in the patient group in comparison to controls, as assessed by immunohistochemistry evaluations. CONCLUSIONS: In this study, we showed an elevation in the expression levels of ß5 integrin when stimulated by IL-4. It is strongly indicated that this integrin acts as an important mediator during macrophage to macrophage fusion and development of giant cells.

Extracts of Scrophularia frigida Boiss display potent antitumor effects in human breast cancer cells by inducing apoptosis and inhibition of expression of the human epidermal growth factor receptor 2.

Some species of the Scrophularia genus have been extensively used as a natural remedy for treatment of various medical conditions. The objective of this study was to evaluate the growth inhibitory activity of Scrophularia frigida Boiss extracts as well as to study the effect of the potent extracts on the induction of apoptosis and cell cycle arrest on human breast cancer cells. S. frigida Boiss extracts exhibited obvious inhibitory effects on the growth of cancer cells and induced apoptosis. It is suggested that the extracts exert their anti-proliferative effect through multiple implications such as suppressing growth, arresting the cell cycle, increased DNA fragmentation, downregulation of the expression of human epidermal growth factor receptor 2 and myeloid cell Leukemia-1, and upregulation of pro-apoptotic messenger RNAs like caspase-3 and caspase-9. Taken together, the results obtained indicate that S. frigida Boiss extracts may contain effective compounds that can be used as a therapeutic anticancer agent.

Trafficking mechanism of bone marrow-derived mesenchymal stem cells toward hepatocellular carcinoma HepG2 cells by modulating Endoglin, CXCR4 and TGF-ß.

Mesenchymal stem cells (MSCs) display differential migration ability toward different tumor-released factors. Migration of MSCs is highly important in induction of proliferation and invasiveness of hepatocellular carcinoma (HepG2) cells. In this study, the role of CXCR4/CXCL12 axis and TGF-ßR signaling were evaluated in the migration of MSCs toward HepG2 cells. The MSCs were incubated with SDF-1α (CXCL12), antagonists of CXCR4, TGF-ßR, and co-receptor of TGF-ß, (endoglin) for 48h. Then, the migration of these cells toward HepG2 cells was analyzed using in vitro migration assay. SDF-1α at a concentration of 100nM MSCs revealed the highest migration rate toward the conditioned medium (1.62 fold compared to the migration of un-treated MSCs; p<0.05). Applying combination of the antagonists against CXCR4, TGF- ßR, and co-receptor of TGF-ß decreased the migration rate significantly (4.51 fold; p<001). Western blot analysis confirmed that RhoA activity is a core modulator in migration pathway. This study demonstrated that CXCR4 and TGF-ßR signaling are important for migration of MSCs toward HepG2 cells. Identifying the key mediators in the migration of MSCs toward hepatocellular carcinoma cells and then development of the therapeutic inhibitors against these factors can be considered as an essential strategy in suppression of tumor progression and metastasis.

An overview of the history, applications, advantages, disadvantages and prospects of gene therapy.

Gene therapy has become a significant issue in science-related news. The principal concept of gene therapy is an experimental technique that uses genes to treat or prevent disease. Although gene therapy was originally conceived as a way to treat life-threatening disorders (inborn defects, cancers) refractory to conventional treatment, it is now considered for many non–life-threatening conditions, such as those adversely impacting a patient’s quality of life. An extensive range of efficacious vectors, delivery techniques, and approaches for developing gene-based interventions for diseases have evolved in the last decade. The lack of suitable treatment has become a rational basis for extending the scope of gene therapy. The aim of this review is to investigate the general methods by which genes are transferred and to give an overview to clinical applications. Maximizing the potential benefits of gene therapy requires efficient and sustained therapeutic gene expression in target cells, low toxicity, and a high safety profile. Gene therapy has made substantial progress albeit much slower than was initially predicted. This review also describes the basic science associated with many gene therapy vectors and the present progress of gene therapy carried out for various surface disorders and diseases. The conclusion is that, with increased pathobiological understanding and biotechnological improvements, gene therapy will become a standard part of clinical practice.

siRNA-mediated inhibition of survivin gene enhances the anti-cancer effect of etoposide in U-937 acute myeloid leukemia cells.

Acute myeloid leukemia (AML) is one of the most frequent types of leukemia which mostly affects adult people. Resistance to therapeutic drugs is considered as a major clinical concern resulting in a weaker response to chemotherapy, disease relapse and decreased survival rate. Survivin, a member of Inhibitor of Apoptosis Proteins (IAPs), is associated with drug resistance and inhibition of apoptotic mechanisms in numerous hematological malignancies. In the present study, we examined the combined effect of etoposide and siRNA-mediated silencing of survivin on U-937 acute myeloid leukemia cells. The AML cells were transfected with survivin specific siRNA and gene knockdown was confirmed by quantitative real time PCR and western blotting. Subsequently, U-937 cells were assessed for response to etoposide treatment and apoptosis rate was measured with flowcytometery. The cytotoxic effects in siRNA-etoposide group were measured and compared to etoposide single therapy group. Survivin siRNA effectively knocked down the mRNA and protein levels of survivin, which led to lower cell proliferation and enhanced apoptosis. Furthermore, combined treatment of etoposide and survivin siRNA synergistically increased the cell toxic effects of etoposide and its ability to induce apoptosis.

Silencing of myeloid cell leukemia-1 by small interfering RNA improves chemosensitivity to etoposide in u-937 leukemic cells.

A key issue in the treatment of acute myeloid leukemia (AML) is the development of drug resistance to chemotherapeutic agents. Overexpression of myeloid cell leukemia-1 (Mcl-1), an anti-apoptotic protein, is associated with tumor progression and drug resistance in leukemia and several cancers. The purpose of this study was to investigate the effect of specific Mcl-1 small interference RNA (siRNA) on the proliferation and chemosensitivity of U-937 AML cell to etoposide. The siRNA transfection was conducted using Lipofectamine™ 2000. Quantitative real-time RT-PCR (qRT-PCR) and Western blot analysis were employed to measure the expression levels of mRNA and protein, respectively. To evaluate tumor cell growth after siRNA transfection, Trypan blue exclusion assay was conducted. The cytotoxic effects of siRNA and etoposide were determined using MTT assay on their own and in combination. DNA-histone ELISA and annexin-V/FITC assays were performed to study the apoptosis. Mcl-1 siRNA transfection significantly blocked the expression of Mcl-1 mRNA and protein in a time-dependent manner, leading to a strong growth inhibition and enhanced apoptosis (P less than 0.05). Furthermore, pretreatment with Mcl-1 siRNA, synergistically enhanced the cytotoxic and apoptotic effects of etoposide (P less than 0.05). Our results demonstrated that Mcl-1 plays a fundamental role in the survival and resistance of U-937 cells to etoposide. Therefore, Mcl-1 can be considered an attractive target in gene therapy of AML patients and siRNA-mediated silencing of this gene may be a novel strategy in AML treatment.

Effects of Urtica dioica dichloromethane extract on cell apoptosis and related gene expression in human breast cancer cell line (MDA-MB-468).

Breast cancer is the most common cancer among women in worldwide, especially in developing countries. Therefore, a large number of anticancer agents with herbal origins have been reported against this deadly disease. This study is the first to examine the cytotoxic and apoptotic effects of Urtica dioica in MDA-MB-468, human breast adenocarcinoma cells. The 3-(4,5-dimethylethiazol-2 yl)-2,5- diphenyltetrazolium (MTT) reduction and trypan-blue exclusion assay were performed in MDA-MB-468 cells as well as control cell line L929 to analyze the cytotoxic activity of the dichloromethane extract. In addition, Apoptosis induction of Urtica dioica on the MDA-MB-468 cells was assessed using TUNEL (terminal deoxy transferase (TdT)-mediated dUTP nick- end labeling) assay and DNA fragmentation analysis and real-time polymerase chain reaction (PCR). The results showed that the extract significantly inhibited cell growth and viability without inducing damage to normal control cells. Nuclei Staining in TUNEL and DNA fragments in DNA fragmentation assay and increase in the mRNA expression levels of caspase-3, caspase-9, decrease in the bcl2 and no significant change in the caspase-8 mRNA expression level, showed that the induction of apoptosis was the main mechanism of cell death that induce by Urtica dioica extract. Our results suggest that urtica dioica dichloromethane extract may contain potential bioactive compound(s) for the treatment of breast adenocarcinoma.

Selective activation of α7 nicotinic acetylcholine receptor by PHA-543613 improves Aß25-35-mediated cognitive deficits in mice.

Agonists of α7 nicotinic acetylcholine receptors (nAChRs) are currently being considered as therapeutic approaches for managing cognitive deficits in Alzheimer's disease (AD). Present study was designed to evaluate the effect of α7 nAChR selective activation by PHA-543613 (PHA) on beta-amyloid (Aß)25-35-mediated cognitive deficits in mice. For this purpose, PHA (1mg/kg, i.p.), a selective α7 nAChR agonist, and galantamine (Gal) (3mg/kg, s.c.), an acetylcholine-esterase inhibitor (AChEI) effects on α7 nAChR were tested in Aß25-35-received (intracerebroventricular, 10 nmol) mice model of AD. Methyllycaconitine (MLA) (1mg/kg, i.p.), a α7 nAChR antagonist, was used for receptor blockage effects evaluation. Working and reference memory in animals was assessed by the Morris water maze (MWM) task. The mRNA and protein levels of α7 subunit were analyzed by real-time PCR and Western blotting, respectively. PHA and Gal, ameliorate Aß-impaired working and reference memory. However, Gal had less effect than PHA in this regard. Pretreatment with MLA reverses both Gal and PHA effects in MWM. PHA and Gal treatment prevent Aß-induced α7 subunit protein reduction, but Gal has lesser effect than PHA. This effect blocked by pretreatment with MLA. In neither the pretreatment nor treatment group, the mRNA levels of nAChR α7 subunit were significantly changed. Therefore, α7 nAChR activation, reduces Aß-induced cognitive deficits and increases the α7 protein level and subsequent neuron survival. However, blockage of receptor, increases Aß toxicity and cognitive impairment and reduces the α7 nAChR protein level and flowing neuroprotection.