Sunde Yilmaz Susluer

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.

Synthesis, crystal structures, in vitro DNA binding, antibacterial and cytotoxic activities of new di- and polynuclear silver(I) saccharinate complexes with tertiary monophosphanes.

Four new silver(I) saccharinate (sac) complexes, [Ag(μ-sac)(PPh3)]2 (1), [Ag(μ-sac)(PPh2Cy)]2 (2), [Ag(μ-sac)(PPhCy2)]2 (3) and [Ag(μ-sac)(PCy3)]n (4), where PPh3=triphenylphosphane, PPh2Cy=cyclohexyldiphenylphosphane, PPhCy2=dicyclohexylphenylphosphane and PCy3=tricyclohexylphosphane, have been synthesized and fully characterized by elemental analysis, IR, NMR, ESI-MS and single crystal X-ray diffraction. Fluorescence ethidium bromide displacement indicate that all complexes bind to fish sperm (FS) DNA by intercalation with binding constants (KA) of 29.1±0.26×10(5)M(-1) for 1, 2.54±0.12×10(5)M(-1) for 2, 2.42±0.08×10(5)M(-1) for 3, 0.19±0.03×10(5)M(-1) for 4. The relative viscosities of the FS-DNA solutions increase with increasing of the complex concentration, providing strong evidence for the intercalation mode. The gel electrophoresis assay further confirms their binding with the pBR322 plasmid DNA. The MIC values of the silver(I) complexes are generally higher than those of AgNO3 and silver sulfadiazine, but 1 presents a promising activity against Salmonellatyphimurium and Staphylococcusaureus. All complexes are highly cytotoxic on human lung carcinoma (A549) and human breast adenocarcinoma (MCF-7) cell lines with IC50 values ranging from 0.82 to 3.13μM.

Di- and polynuclear silver(I) saccharinate complexes of tertiary diphosphane ligands: synthesis, structures, in vitro DNA binding, and antibacterial and anticancer properties.

A series of new silver(I) saccharinate (sac) complexes, [Ag2(sac)2(μ-dppm)H2O]·H2O (1), {[Ag2(μ-sac)2(μ-dppe)]·3H2O·CH2Cl2}n (2), [Ag2(μ-sac)2(μ-dppp)]n (3), and [Ag(sac)(μ-dppb)]n (4) [dppm is 1,1-bis(diphenylphosphino)methane, dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane], have been synthesized and characterized by C, H, N elemental analysis, IR spectroscopy, 1H NMR, 13C NMR, and 31P NMR spectroscopy, electrospray ionization mass spectrometry, and thermogravimetry–differential thermal analysis. Single-crystal X-ray studies show that the diphosphanes act as bridging ligands to yield a dinuclear complex (1) and one-dimensional coordination polymers (2 and 4), whereas the sac ligand adopts a μ2-N/O bridging mode in 2, and is N-coordinated in 1 and 4. The interaction of the silver(I) complexes with fish sperm DNA was investigated using UV–vis spectroscopy, fluorescence spectroscopy, and agarose gel electrophoresis. The binding studies indicate that the silver(I) complexes can interact with fish sperm DNA through intercalation, and complexes 1 and 3 have the highest binding affinity. The gel electrophoresis assay further confirms the binding of the complexes with the pBR322 plasmid DNA. The minimum inhibitory concentrations of the complexes indicate that complex 1 exhibits very high antibacterial activity against standard bacterial strains of Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus, being much higher than those of AgNO3, silver sulfadiazine, ciprofloxacin, and gentamicin. Moreover, complexes 1–3 exhibit very high cytotoxic activity against A549 and MCF-7 cancer cell lines, compared with AgNO3 and cisplatin. The bacterial and cell growth inhibitions of the silver(I) complexes are closely related to their DNA binding affinities.

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.

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.

Analysis of dysregulated long non-coding RNA expressions in glioblastoma cells.

Long non coding RNAs (lncRNAs) are associated with various biological roles such as embryogenesis, stem cell biology, cellular development and present specific tissue expression profiles. Aberrant expression of lncRNAs are thought to play a critical role in the progression and development of various cancer types, including gliomas. Glioblastomas (GBM) are common and malignant primary brain tumours. Brain cancer stem cells (BCSC) are isolated from both low and high-grade tumours in adults and children, by cell fraction which express neuronal stem cell surface marker CD133. The purpose of this study was to investigate the expression profiles of lncRNAs in brain tumour cells and determine its potential biological function. For this purpose, U118MG-U87MG; GBM stem cell series were used. Human parental brain cancer cells were included as the control group; the expressions of disease related human lncRNA profiles were studied by LightCycler 480 real-time PCR. Expression profiles of 83 lncRNA genes were analyzed for a significant dysregulation, compared to the control cells. Among lncRNAs, 51 lncRNA genes down-regulated, while 8 lncRNA genes were up-regulated. PCAT-1 (-2.36), MEG3 (-5.34), HOTAIR (-2.48) lncRNAs showed low expression in glioblastoma compared to the human (parental) brain cancer stem cells, indicating their role as tumour suppressor genes on gliomas. As a result, significant changes for anti-cancer gene expressions were detected with disease-related human lncRNA array plates. Identification of novel target genes may lead to promising developments in human brain cancer treatment.

Evaluation of cancer imaging potential and photodynamic therapy efficacy of copper (II) benzyloxypheophorbide-a.

Abstract The biological potential of a synthetic copper chlorophyll derivative was investigated via in vivo and in vitro experiments. The Cu-chlorophyll derivative photosensitizer (Cu-PH-A) was labeled with 131I with high efficiency (92.9 ± 4.2%) using the iodogen method. Cell culture studies were performed with the MCF-7 and MDAH-2774 cell lines after radiolabeling. The photosensitizing activity of Cu-PH-A was more effective in MDAH-2774 cells than in MCF-7 cells at a concentration of 50 μM. When the biodistribution in female Albino Wistar rats was examined, uptake of the radiolabeled photosensitizer was maximal in the liver and ovaries after 60 min. It is concluded that radiolabeled Cu-chlorophyll derivative photosensitizer has high uptake in ovaries in normal rats. In addition, the intercellular uptake and PDT efficacy of the Cu-PH-A in MDAH-2774 were good compared with MCF-7 cells. This photosensitizer could be useful for both ovary tumour imaging and PDT.

Evaluation of the miRNA profiling and effectiveness of the propolis on B-cell acute lymphoblastic leukemia cell line

Acute lymphoblastic leukemia (ALL) is one of the most frequent causes of death from cancer. Since the discovery of chemotherapeutic agents, ALL has become a model for improvement of survival. In parallel to this, serious side effects were observed and new natural therapeutic options has been discussed. One of these substances is called propolis which is a resinous substance gathered by honeybees. In the molecular era, miRNAs have been shown to play crucial roles in the development of many clinical conditions. The aim of this study is to evaluate the effect of Aydın propolis on 81 human miRNA activity in CCRF-SB leukemia cell line. Apoptotic effects of propolis on cell lines were also evaluated and apoptosis were found to be induced 1.5 fold in B-cell leukemia cells. The expression of 63 miRNAs (46 miRNAs were downregulated, 19 miRNAs were upregulated) in propolis treated leukemia cells have changed significantly (p<0.05). In conclusion propolis has changed expression of miRNAs which have epigenetic effects on leukemic cells. It is thought that it can be a promising agent for ALL treatment for future studies.

Antileukemic effect of paclitaxel in combination with metformin in HL-60 cell line

Acute promyelocytic leukemia (APL) is a subtype of AML that is a mixture of hematological malignancy, characterized by a specific translocation t(15;17). The using of all-trans retinoic acid (ATRA) with arsenic trioxide (ATO) or chemotherapeutic agents or both of these agents, composes main treatment strategy of APL. While it is possible to achieve success in treatment of low-risk APL with current treatment regimens, such success is not mentioned in high-risk APL. So, it may develop new approaches for treatment regimens for high-risk APL. In the present study, we aimed to investigate the effects of combinational of a classic anticancer agent paclitaxel and antidiabetic agent metformin on HL-60 APL cell line. The combination dose of paclitaxel and metformin was determined by WST-1 analysis. The effect of combinational dose on apoptosis was assessed in fluorescence microscope after using AnnexinV-EGFP Apoptosis and JC-1 Assay Kit. The effect of combinational dose on cell cycle, apoptosis and differentiation, and signaling pathways were determined investigating gene expression changes by using real time qRT-PCR. The combinational dose of paclitaxel and metformin was determined as 4.8nM and 398.7μM for 72h, respectively. The combination dose significantly increased apoptosis for 48h. In expression changes of genes associated cell cycle, apoptosis, cytokines, co-stimulator molecules, NF-kB and MAP/MAPK pathways, TLRs (Toll-like receptors) were found to be decreased or increased to provide apoptosis or differentiation. Consequently, we suggest that the combination of paclitaxel and metformin can be used as an option assessable for development of new treatment strategies for APL.

The effect of tomatine on metastasis related matrix metalloproteinase (MMP) activities in breast cancer cell model

Breast cancer is one of the most common malignancies in women and metastasis is the cause of morbidity and mortality in patients. In the development of metastasis, the matrix metalloproteinase (MMP) family has a very important role in tumor development. MMP-2 and MMP-9 work together for extracellular matrix (ECM) cleavage to increase migration. Tomatine is a secondary metabolite that has a natural defense role against plants, fungi, viruses and bacteria that are synthesized from tomato. In additıon, tomatine is also known that it breaks down the cell membrane and is a strong inhibitor in human cancer cells. In this study, it was aimed to evaluate the effect of tomatine on cytotoxicity, apoptosis and matrix metalloproteinase inhibition in MCF-7 cell lines. Human breast cancer cell line (MCF-7) was used as a cell line. In MCF-7 cells, the IC50 dose of tomatine was determined to be 7.07μM. According to the control cells, apoptosis increased 3.4 fold in 48thh. Activation of MMP-2, MMP-9 and MMP-9\NGAL has been shown to decrease significantly in cells treated with tomatine by gelatin zymography compared to the control. As a result, matrix metalloproteinase activity and cell proliferation were suppressed by tomatine and this may provide support in treatment methods.