Cigir Biray Avci

Therapeutic Potential of an Anti-diabetic Drug, Metformin: Alteration of miRNA expression in Prostate Cancer Cells

BACKGROUND AND AIMS Prostate cancer is the most commonly diagnosed cancer in males in many populations. Metformin is the most widely used anti-diabetic drug in the world, and there is increasing evidence of a potential efficacy of this agent as an anti-cancer drug. Metformin inhibits the proliferation of a range of cancer cells including prostate, colon, breast, ovarian, and glioma lines. MicroRNAs (miRNAs) are a class of small, non- coding, single-stranded RNAs that downregulate gene expression. We aimed to evaluate the effects of metformin treatment on changes in miRNA expression in PC-3 cells, and possible associations with biological behaviour. MATERIALS AND METHODS Average cell viability and cytotoxic effects of metformin were investigated at 24 hour intervals for three days using the xCELLigence system. The IC50 dose of metformin in the PC-3 cells was found to be 5 mM. RNA samples were used for analysis using custom multi-species microarrays containing 1209 probes covering 1221 human mature microRNAs present in miRBase 16.0 database. RESULTS Among the human miRNAs investigated by the arrays, 10 miRNAs were up-regulated and 12 miRNAs were down-regulated in the metformin-treated group as compared to the control group. In conclusion, expression changes in miRNAs of miR-146a, miR-100, miR-425, miR-193a-3p and, miR-106b in metformin-treated cells may be important. This study may emphasize a new role of metformin on the regulation of miRNAs in prostate cancer.

Caffeic acid phenethyl ester triggers apoptosis through induction of loss of mitochondrial membrane potential in CCRF-CEM cells

PurposeCAPE (caffeic acid phenethyl ester) is one of the most valuable and investigated component of propolis which is composed by honeybees. In the current study, we aimed at examining apoptotic effects of CAPE on CCRF-CEM leukemic cells and at determining the roles of mitochondrial membrane potential (MMP) in cell death.MethodsTrypan blue and XTT methods were used to evaluate the cytotoxicity. Apoptosis was examined by ELISA-based oligonucleotide and acridine orange/ethidium bromide dye techniques. Loss of mitochondrial membrane potential was evaluated using JC-1 dye by flow cytometric analysis and under fluorescent microscope.ResultsWe detected the time- and dose-dependent increases in cytotoxic effect of CAPE on CCRF-CEM cells. ELISA and acridine orange/ethidium bromide results showed that apoptotic cell population increased significantly in CCRF-CEM cells exposed to increasing concentrations of CAPE. On the other hand, there was significant loss of MMP determined in response to CAPE in CCRF-CEM cells.ConclusionThis in vitro data by being supported with clinical data may open the way of the potential use of CAPE for the treatment of leukemia.

Role of mTOR in glioblastoma

Mammalian target of rapamycin (mTOR), which is a member of the serine/threonine protein kinase family, is a protein complex that has a central role of cell growth and proliferation. mTOR emerges as a critical cell growth checkpoint on phosphoinositide 3-kinase (PI3K) signaling pathway. In this case mTOR has become an important therapeutic target for glioblastoma (GBM) that is one of the most deadly types of cancer. Various combination treatments including inhibition of mTOR may provide more significant results in the treatment of GBM. In addition to new mTOR targets, which may have a plant origin form, more potent mTOR inhibitors by utilizing the computational methodology may emerge as a hope for GBM therapy. In the future, a better understanding of the functional properties of mTORC2 with its potent effective inhibitors may help design more efficiently GBM treatment modalities.

The roles of non-coding RNAs in Parkinson's disease.

Parkinson’s disease (PD) is considered as a high prevalence neurodegenerative disorders worldwide. Pathologically, the demise of dopamine-producing cells, in large part due to an abnormal accumulation of the α-synuclein in the substantia nigra, is one of the main causes of the disease. Up until now, many de novo investigations have been conducted to disclose the mechanisms underlying in PD. Among them, impacts of non-coding RNAs (ncRNAs) on the pathogenesis and/or progression of PD need to be highlighted. microRNAs (miRNAs) and long ncRNAs (lncRNAs) are more noteworthy in this context. miRNAs are small ncRNAs (with 18–25 nucleotide in length) that control the expression of multiple genes at post-transcriptional level, while lncRNAs have longer size (over 200 nucleotides) and are involved in some key biological processes through various mechanisms. Involvement of miRNAs has been well documented in the development of PD, particularly gene expression. Hence, in this current review, we will discuss the impacts of miRNAs in regulation of the expression of PD-related genes and the role of lncRNAs in the pathogenesis of PD.

Type 2 Diabetes Inhibited Human Mesenchymal Stem Cells Angiogenic Response by Over-Activity of the Autophagic Pathway

The current study aimed to address the impact of serum from type 2 diabetes patients on the angiogenic properties of human bone marrow mesenchymal stem cells and its relationship to autophagy signaling. Human primary stem cells were enriched and incubated with serum from diabetic and normal subjects for 7 days. Compared to data from the control group, diabetic serum was found to induce a higher cellular death rate (P < 0.001) and apoptotic changes (P < 0.01). We also showed that diabetic condition significantly abolished angiogenesis tube formation on Matrigel substrate, decreased cell chemotaxis (P < 0.01) in response to SDF‐1α, and inhibited endothelial differentiation rate (P < 0.0001). Western blotting showed autophagic status by high levels of P62 (P < 0.0001), beclin‐1 (P < 0.0001), and increase in LC3II/I ratio (P < 0.001). In vivo Matrigel plug assay revealed that supernatant conditioned media prepared from cells exposed to diabetic serum caused a marked reduction in the recruitment of VE‐cadherin‐ (P < 0.01) and α‐SMA‐positive (P < 0.0001) cells 7 days after subcutaneous injection. PCR expression array analysis confirmed the overexpression of autophagy and apoptosis genes in cultured cells in response to a diabetic condition (P < 0.05). Using bioinformatic analysis, we noted a crosstalk network between DM2, angiogenesis, and autophagy signaling. DM2 could potently modulate angiogenesis by the interaction of IL‐1β with downstream insulin receptor and upstream androgen receptor. Corroborating to data, diabetic serum led to abnormal regulation of P62 during the angiogenic response. These data demonstrate that diabetic serum decreased human mesenchymal stem cell angiogenic properties directly on angiogenesis pathways or by the induction of autophagy signaling. J. Cell. Biochem. 118: 1518–1530, 2017.

Genistein-induced mir-23b expression inhibits the growth of breast cancer cells

Aim of the study Genistein, an isoflavonoid, plays roles in the inhibition of protein tyrosine kinase phosphorylation, induction of apoptosis, and cell differentiation in breast cancer. This study aims to induce cellular stress by exposing genistein to determine alterations of miRNA expression profiles in MCF-7 cells. Material and methods XTT assay and trypan blue dye exclusion assays were performed to examine the cytotoxic effects of genistein treatment. Expressions of miRNAs were quantified using Real-Time Online RT-PCR. Results The IC50 dose of genistein was 175 μM in MCF-7 cell, line and the cytotoxic effect of genistein was detected after 48 hours. miR-23b was found to be up-regulated 56.69 fold following the treatment of genistein. It was found that miR-23b was upregulated for MCF-7 breast cancer cells after genistein treatment. Conclusions Up-regulated ex-expression of miR-23b might be a putative biomarker for use in the therapy of breast cancer patients. miR-23b up-regulation might be important in terms of response to genistein.

Design of polyethylene glycol-polyethylenimine nanocomplexes as non-viral carriers: mir-150 delivery to chronic myeloid leukemia cells

MicroRNAs (miRNAs) are acknowledged as indispensable regulators relevant in many biological processes, and they have been pioneered as therapeutic targets for curing disease. miRNAs are single‐stranded, small (19–22 nt) regulatory non‐coding RNAs whose deregulation of expression triggers human cancers, including leukemias, mainly through dysregulation of expression of leukemia genes. miRNAs can function as tumour suppressors (suppressing malignant potential) or oncogenes (activating malignant potential) like actors of complex diseases. To address the issue of overcoming instability and low transfection efficiency in vitro, the polyethylene glycol–polyethyleneimine (PEG–PEI) nanoparticle was used as non‐viral vector carrier for miR‐150 transfection, which is downregulated in chronic myeloid leukemia. PEG–PEI [PEG(550)3‐g‐PEI(1800)]/miRNA nanocomplexes were synthesised and characterised by particle size distribution (PSD), polydispersity index (PDI) and zeta potential, surface charge, their cytotoxicity, and transfection efficiency. Interaction with human leukemia cells (K‐562 and KU812) and control cells NCI‐BL2347 with them has been investigated. The transfection efficiency of PEG–PEI/miRNA at N/P 26 rose 6.7‐fold above the control by qRT‐PCR. The size of homogenous nanocomplexes (PBI < 0.5) was 160.8 ± 11 nm. The data indicate that PEG–PEI may be an encouraging non‐viral carrier for altering miRNA expression in the treatment of chronic myeloid leukemia, with many advantages such as relatively high miRNA transfection efficiency and low cytotoxicity.

Quercetin-induced apoptosis involves increased hTERT enzyme activity of leukemic cells

Abstract We aimed to examine the growth suppressive effects of quercetin on acute promyelocytic and lymphoblastic leukemia and chronic myeloid leukemia, and to find out whether the growth suppression is related to the blocking of telomerase enzyme activity. Cytotoxic effects of quercetin were shown by trypan blue analyses. Apoptotic effects of quercetin were examined by acridine orange and ethidium bromide staining by fluorescence microscopy. The effects of quercetin on telomerase enzyme activity were shown by hTERT Quantification Kit. Our results demonstrated that quercetin has antiproliferative and apoptotic effects on T-cell acute lymphoblastic leukemia (ALL), acute promyelocytic leukemia, and chronic myeloid leukemia (CML) cells. We also showed for the first time by this study that quercetin suppresses the activity of telomerase in ALL and CML cells. The results of this study show the importance of quercetin for its therapeutic potential in treatment of leukemias.

New approaches for cancer immunotherapy

Immunotherapy is a promising field that offers alternative methods for treatment of cancer. The current strategy consists of cancer vaccines, monoclonal antibodies, and cellular therapies. Cancer vaccines aim to eradicate cancer cells via immune system. Thus, they may attack these cells derived from any type of cancer, besides their role in preventing cancer. Lymphocytes and dendritic cells are often used in cellular therapy. In addition, monoclonal antibodies are designed to target specific antigens found in cancer cells. Currently, at least 12 clinically approved monoclonal antibodies are being used and many cancer vaccines are being developed with ongoing phase studies for cancer therapy. Relevant studies are focused on glioma and several other cancer types. Correspondingly, the combination of effective methods may enhance the efficacy of immunotherapy. It is thought that particularly immune checkpoint inhibitors will play a crucial role in immunotherapeutic approaches.

In vitro evaluation of 99mTc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines

Abstract Bombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a radiopharmaceutical for pancreatic tumor imaging.