Lütfi Tutar

Heat Shock Proteins; An Overview

Heat shock proteins (Hsps) protect protein substrates against conformational damage to promote the function of the proteins, prevent aggregation and prevent formation of toxic inclusion bodies. Protein aggregates and fibrils have been associated with neurodegenerative diseases and with inclusion bodies. High-level expression of recombinant protein for biotechnological purposes often leads to insoluble inclusion bodies. Therefore, misfolded proteins must be properly folded or must be degraded through heat shock protein action. This function protects cells against cytotoxic outcomes. In addition to their cytoprotective roles, Hsps are involved in other functions since Hsps exist in all types of cells and tissues. Therefore, several diseases are associated with alterations of these biochemical functions. This first review of the theme issue will discuss general properties of Hsps concisely along with their potential use in pharmaceutical and biotechnological applications.

MicroRNAs and Cancer; an Overview

MiRNAs are a family of small, endogenous, and evolutionarily conserved non-coding ribonucleic acids that have been involved in the regulation of several essential, cellular, and functional processes. MicroRNAs are known to play key roles in all types of cancer and function as oncogenes (oncomirs) or tumour-suppressors in up-regulation or down-regulation processes respectively. MiRNAs have potential power to be examined as prognostic and diagnostic biomarkers. Modulating miRNAs, based on two major approaches (miRNA mimics and miRNA antagonists), is used for clinical development of therapeutic miRNAs. This review emphasizes the latest discovery in the field of miRNA research involved in cancer, biomarkers, and therapeutics.

Isolation and identification of free-living amoebae from tap water in Sivas, Turkey.

The present work focuses on a local survey of free-living amoebae (FLA) that cause opportunistic and nonopportunistic infections in humans. Determining the prevalence of FLA in water sources can shine a light on the need to prevent FLA related illnesses. A total of 150 samples of tap water were collected from six districts of Sivas province. The samples were filtered and seeded on nonnutrient agar containing Escherichia coli spread. Thirty-three (22%) out of 150 samples were found to be positive for FLA. The FLA were identified by morphology and by PCR using 18S rDNA gene. The morphological analysis and partial sequencing of the 18S rDNA gene revealed the presence of three different species, Acanthamoeba castellanii, Acanthamoeba polyphaga, and Hartmannella vermiformis. Naegleria fowleri, Balamuthia mandrillaris, or Sappinia sp. was not isolated during the study. All A. castellanii and A. polyphaga sequence types were found to be genotype T4 that contains most of the pathogenic Acanthamoeba strains. The results indicated the occurrence and distribution of FLA species in tap water in these localities of Sivas, Turkey. Furthermore, the presence of temperature tolerant Acanthamoeba genotype T4 in tap water in the region must be taken into account for health risks.

Therapeutic Targeting of microRNAs in Cancer: Future Perspectives.

Preclinical Research

Regulation of oncogenic genes by MicroRNAs and pseudogenes in human lung cancer.

Lung cancer is one of the most common mortal cancer types both for men and women. Several different biomarkers have been analyzed to reveal lung cancer prognosis pathways for developing efficient therapeutics and diagnostic agents. microRNAs (miRNAs) and pseudogenes are critical biomarkers in lung cancer and alteration of their expression levels has been identified in each step of lung cancer tumorigenesis. miRNAs and pseudogenes are crucial gene regulators in normal cells as well as in lung cancer cells, and they have both oncogenic and tumor-suppressive roles in lung cancer tumorigenesis. In this study, we have determined the relationship between lung cancer related oncogenes and miRNAs along with pseudogenes in lung cancer, and the results indicate their potential as biological markers for diagnostic and therapeutic purposes.

Design, Synthesis, and Evaluation of Heat Shock Protein 90 Inhibitors in Human Breast Cancer and Its Metastasis

BACKGROUND Despite development of novel cancer drugs, invasive ductal breast carcinoma and its metastasis are still highly morbid. Therefore, new therapeutic approaches are being developed and Hsp90 is an important target for drug design. For this purpose, a series of benzodiazepine derivatives were designed and synthesized as novel Hsp90 inhibitor. METHODS Benzodiazepine derivatives anticancer activities were determined by XTT cell proliferation assay against human breast cancer cell line (MCF-7). Effects of the compounds on endothelial function were monitored on human vascular endothelium (HUVEC) cell line as well. In order to determine the anti-proliferative mechanism of the compounds, in silico molecular docking studies were performed between Hsp90 ATPase domain and the benzodiazepine derivatives. Further, these compounds perturbation on Hsp90 ATPase function were tested. Fluorescence binding experiments showed that the derivatives bind Hsp90 effectively. Expression analysis of known cancer drug target genes by PCR array experiments suggest that the benzodiazepine derivatives have remarkable anticancer activity. RESULTS A representative Benzodiazepine derivative D5 binds Hsp90 with Kd value of 3,93 μM and with estimated free energy of binding -7.99 (kcal/mol). The compound decreases Hsp90 ATPase function and inhibit Hsp90 client protein folding activity. The compound inhibits expression of both Hsp90 isoforms and key proteins (cell cycle receptors; PLK2 and TERT, kinases; PI3KC3 and PRKCE, and growth factors; IGF1, IGF2, KDR, and PDGFRA) on oncogenic pathways. CONCLUSION Benzodiazepine derivatives presented here display anticancer activity. The compounds effect on both breast cancer and endothelial cell lines show their potential as drug templates to inhibit breast cancer and its metastasis.

Heat Shock Protein as Emerging Oncologic Drug Targets

Lutfi Tutar1, Kübra Açıkalın Coskun2 and Yusuf Tutar2* 1Department of Biology, Graduate School of Natural and Applied Sciences, Kahramanmaraş Sütçü İmam University, Kahramanmaraş, Turkey 2Division of Biochemistry, Department of Basic Sciences, Faculty of Pharmacy, Sivas Cumhuriyet University, Turkey *Corresponding author: Yusuf Tutar, Division of Biochemistry, Department of Basic Sciences, Faculty of Pharmacy, Sivas Cumhuriyet University, Turkey, Tel: +90 3462191010; E-mail: ytutar@yahoo.com

Hsp70 from Cyprinion macrostomus macrostomus and Garra rufa obtuse: Stability and stability-dependent activity

Two fish species, Cyprinion macrostomus macrostomus and Garra rufa obtuse, tolerate adverse conditions in the Kangal hot springs and cope with multiple stressors such as food deprivation, extreme temperature, toxins, protein degradation, hypoxia, and microbial damage. These fish have evolved strategies to counteract the stressors including the induction of heat shock proteins (Hsps). Hsps play an essential role in maintaining cellular homeostasis, and one of the key proteins in the mechanism is Hsp70. Hsp70 itself is exposed to the same stressors as all other proteins, and, hence, the stability of Hsp70 was investigated. For this purpose, Hsp70 ATPase activity was determined at different urea concentrations. It was found that the protein maintains considerable ATP hydrolysis activity at higher denaturant conditions. Temperature effects on the substrate peptide binding showed that Hsp70s bind prominently at elevated temperatures. Furthermore, temperature effects on Hsp70 aggregation indicated that the presence of nucleotides decreases the aggregation process. The present work has determined the stability and activity of cmHsp70 and grHsp70 themselves under extreme conditions. The stability of the Hsp70 proteins maintains substrate proteins in the native state, which may aid in the adaptation of the fish species to the hot spring environment.

Drug Dependent Stress and Heat ShockProtein Response

Stress induces radicals and this process triggers several biochemical pathways but most essential problem is the damage caused by the radicals on lipids, proteins, and nucleic acids. To perform biochemical functions, these macromolecules must be working properly. Proteins must be correctly folded so that they can regulate pathways and transmit signals. Under stress, alteration in cellular environment cause proteins to lose their structure. Then, the proteins either lose or alter their function. To scavenge radicals and to chaperone substrate proteins, a set of mechanic proteins are employed.