Aykut Özgür

Synthesis and anticancer activity of acyl thioureas bearing pyrazole moiety.

In this work novel organic based compounds, acyl thiourea derivatives were synthesized and their anticancer activities were investigated. A new series of acyl thiourea derivatives containing pyrazole ring were prepared in good yield through one pot reaction of 4-benzoyl-1, 5-diphenyl-1H-pyrazole-3-carbonyl chloride with ammonium thiocyanate and various amines. The structures of the newly synthesized compounds were confirmed by IR, (1)H NMR, (13)C NMR and elemental analysis. Anticancer activities of synthesized compounds were evaluated on human colon, liver and leukemia cancer cell lines. Cell culture studies have demonstrated significant toxicity of the compounds on the cell lines, and the levels of toxicity have altered in the presence of various side groups. These results confirm that novel pyrazolyl acyl thioureas derived compounds may be utilized for cancer treatment. Furthermore, these compounds have a great potential and significance for further investigations.

Therapeutic Targeting of microRNAs in Cancer: Future Perspectives.

Preclinical Research

Synthesis and biological evaluation of radiolabeled photosensitizer linked bovine serum albumin nanoparticles as a tumor imaging agent

In this study, we reported on the synthesis and biological evaluation of radiolabeled fluorescent dye conjugated bovine serum albumin nanoparticles within the size range 190-210 nm. The bovine serum albumin nanoparticles (BSANPs) were prepared using a desolvation method, and chemical cross-linking was performed using gluteraldehyde. Furthermore, pheophorbide-a (PH-A) was loaded on the BSANPs. The results obtained from dynamic light scattering and electron microscopy have proved that nanoparticles are highly monodisperse and near-spherical shaped. The photo-physical properties of the PH-A-BSANPs were obtained using the spectrophotometric techniques. According to the results, PH-A and BSANPs show high non-covalent interaction. PH-A loaded nanoparticles were labeled with (99m)Tc and the radio-labeling efficiency was determined as 90 ± 1.2%. Biodistribution studies of (99m)Tc labeled PH-A-BSANPs and PH-A were carried out using female Albino Wistar rats, and (99m)Tc-PH-A-BSANPs showed a significantly higher uptake in the breast and uterus than (99m)Tc-PH-A. Cell culture study was carried out in MCF-7 cell line (human breast adenocarcinoma cell line). According to the cell culture studies, (99m)Tc-PH-A-BSANPs showed a higher uptake than (99m)Tc-PH-A. Moreover, PH-A-BSANPs demonstrated good photo-physical properties and BSANPs increased the uptake of PH-A on to the MCF-7 cell line. These results confirm that (99m)Tc labeled PH-A-BSANPs could be utilized for radioimaging.

CO-releasing properties and anticancer activities of manganese complexes with imidazole/benzimidazole ligands

Abstract Carbon monoxide (CO) is an important signaling molecule which plays significant roles in the pathogenesis of cancer. CO is produced by enzymatic degradation of heme in mammals. Heme oxygenase 1 (HO-1) catalyzes the breakdown of heme into CO, ferrous iron, and biliverdin. CO induces HO-1 and inhibits cell proliferation. Cancer cells exposed to several stress factors (hypoxia, reactive oxygen species, cis-platin, and oxidative stress), and HO-1 displays cytoprotective role against oxidative stress and inhibits apoptosis, metastases, angiogenesis, and cell proliferation processes. Therefore, metal containing CO-releasing molecules (CORMs) have been designed as an effective cancer treatment strategy. CORMs are responsible for releasing controlled amounts of CO to cells and tissues. Thus, we synthesized [Mn(CO)3(bpy)L]X manganese containing CORMs [bpy = 2,2′-bipyridine, X = hexafluorophosphate (PF6), trifluoromethanesulfonate (OTf), L = imidazole, methylimidazole, benzimidazole, N-benzylbenzimidazole, N-(4-chlorobenzyl)benzimidazole] to release CO in human invasive ductal breast (MCF-7) cell line. In vitro experiments indicated that the compounds inhibited cell proliferation and exhibited cytotoxic effect on breast cancer cells. Moreover, side groups of the compounds enhanced the anticancer effects in MCF-7 cell line. These manganese containing CORMs gave promising results and may be used as a drug template for effective treatment of invasive ductal breast carcinoma.

Heat Shock Protein 90 Inhibition in Cancer Drug Discovery: From Chemistry to Futural Clinical Applications

Heat shock protein 90 (Hsp90) is an important member of the chaperone protein family and it is involved in stabilization, regulation, and maintenance of oncogenic client proteins with co-chaperones. Cochaperones regulate the ATPase activity of Hsp90 and its interactions with oncogenic client proteins. Therefore, Hsp90 and its co-chaperones have become significant therapeutic targets for cancer treatment. Many chemical compounds have been evaluated for Hsp90 inhibition as well as significant results were obtained in clinical trials. In this paper, we emphasize on the key roles of Hsp90 and its co-chaperones in tumorigenesis and overview therapeutic strategies of Hsp90 inhibition in oncology.

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.

Synthesis and biological evaluation of receptor-based tumor imaging agent: 99mTc-folate-glucaric acid

The aim of the present study was to prepare (99m)Tc-folate-glucaric acid and investigate the radiopharmaceutical potential for tumors imaging that over express folate receptor. Folate-glucaric acid was synthesized and the synthesized folate conjugate was confirmed with (1)H NMR and LC-MS/MS methods. Folate-glucaric acid was labeled with (99m)Tc, and its radiolabelling efficiency was found as 96 ± 2.0%. Biodistribution study of (99m)Tc-folate-glucaric acid was carried out in vivo using two groups of female Albino Wistar rats: folate receptor (FR) saturated and unsaturated. Biodistribution study showed that (99m)Tc-folate-glucaric acid indicated high uptake in folate receptor rich tissues such as breast, ovary and uterus. Therefore, (99m)Tc-folate-glucaric acid shows good radiolabeling and biodistribution in FR organs, the radiolabeled conjugate is a reason potentially useful radiopharmaceutical for detection of FR-positive tumors.

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.

Heat Shock Protein 40-Gok1 Isolation from Toxoplasma gondii RH Strain

Toxoplasma gondii is ubiquitous obligate intracellular parasite and is one of the most important pathogen for humans and animals. In humans, T. gondii has two life forms: tachyzoites and bradyzoites. Tachyzoites form of T. gondii can cause acute infection, and it is called toxoplasmosis. The development of latent bradyzoites from rapidly growing tachyzoites has been linked to cellular and environmental stresses which are associated with heat shock proteins (Hsps). Hsps play a protective role against stressors. Hsp40 is an important member of Hsp family and T. gondii has 36 predicted Hsp40 family members. Therefore, we studied the cloning and biochemical characterization of the T. gondii RH strain Hsp40 protein-Gok1. Hsp40 prevents protein aggregation and induce refolding. Consequently, Hsp40s may play essential roles in the mechanisms of bradyzoite development and survival in the host organism. Hsp40-Gok1 functional and structural properties may facilitate drug design and protein targeting against toxoplasmosis.

Therapeutic Proteins: A to Z

In recent years, therapeutic proteins have become an important growing class of drugs in the pharmaceutics industry. The development of recombinant DNA technology has caused to appreciation of therapeutic value of many proteins and peptides in medicine. Currently, approximately 100 therapeutic proteins obtained approval from Food and Drug Administration (FDA) and they are widely used in the treatment of various diseases such as cancer, diabetes, anemia and infections. This paper will summarize the production processes, pharmaceuticals and physicochemical properties and important classes of therapeutic proteins with their potential use in clinical applications.