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.

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.

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.

BERBERIS VULGARIS FRUIT CRUDE EXTRACT AS A NOVEL ANTI-LEUKAEMIC AGENT

Tumor protein p53 encoded by the TP53 gene in humans is known as a cancer biomarker in patients diagnosed with cancer, and it plays an essential role in apoptosis, genomic stability, and inhibition of angiogenesis. Cancer therapies with common chemotherapy methods are effective, as known, but have some side effects. Berberis vulgaris is traditionally administrated as a cancer drug. The current research aims to evaluate p53 as a biomarker in WEHI-3 cell line and to demonstrate the Berberis vulgaris fruit crude extract (BVFCE) as a new anticancer drug. For this purpose, we evaluated the effect of BVFCE in different concentrations against WEHI-3cell line in vitro and determined the quantitative level of p53 gene in the treated WEHI-3 cells. The results demonstrated that even at only 1 mg/ml concentration of Berberis vulgaris crude extract, there was a low level of p53 biomarker expression on WEHI-3 cells in comparison with doxorubicin. Therefore, the current study suggests BVFCE as a reliable anti-leukaemic drug and candidate for anticancer therapy. However, further investigation need be carried out to confirm its efficiency in vivo.