Cigdem Ichedef

Enzymatic synthesis of 125/131I labeled 8-hydroxyquinoline glucuronide and in vitro/in vivo evaluation of biological influence

8-Hydroxyquinoline (8-OHQ) is a long-known molecule which due to its metal-complexation ability is frequently used for analysis. It is also called oxine. Oxine and derivatives have been investigated to process antitumor and antimicrobial activities. 8-Hydroxyquinolyl-glucuronide (8-OHQ-Glu) was enzymatically synthesized using microsome preparates separated from Hutu-80 cells, labeled with (125)I to perform a radionuclide labeled prodrug and investigated of its biological affinities on Hutu-80 (human duodenum intestinal adenocarcinoma), Caco-2 (human colorectal adenocarcinoma), Detroit 562 (human pharynx adenocarcinoma) cells and ACBRI 519 (primary human small intestine epithelial cells) in this work. UDP-glucuronyl transferase (UDPGT) rich microsome preparates, which are used for glucuronidation in enzymatic synthesis, were extracted from Hutu-80 cells. 8-OHQ-Glu components were labeled using iodogen method with (125)I and (131)I. Structural analyses were performed with LC/MS/MS, (1)H NMR and (13)C-MMR for identify and measure chemical constituents. Results confirmed expected molecular structure. 8-OHQ-Glu could successfully radioiodinated with (125/131)I according to iodogen method. (125)I-8-OHQ-glucuronide incorporated with human gastrointestinal cancer cells such as Detroit-562 (human pharynx adenocarcinoma) (12.6%), Caco-2 (human colorectal adenocarcinoma) (7.8%), Hutu- 80 (human duodenum intestinal adenocarcinoma) (9.5%) and ACBRI 519 (primary human small intestine epithelial cells) (6.40%). (131)I-8-OHQ-Glu was tested in mice bearing subcutaneously implanted Caco-2 colorectal adenocarcinoma cells. The results demonstrated that radioiodinated 8-OHQ-Glu may be promising anticancer prodrug.

Synthesis, radiolabeling and in vivo biodistribution of diethylstilbestrol phosphate derivative (DES-P)

Diethylstilbestrol (DES) is a well known, nonsteroidal estrogen with high affinity for the estrogen receptor (ER). Today DES is used to treat breast and prostate cancers. A phosphate derivative of DES [Diethylstilbestrol diphosphate (DES-P)] which is specific to tumor cells consisting alkaline phosphatase enzyme was synthesized and labeled with 99mTc using tin chloride as reducing agent. In vivo biological activity of 99mTc labeled diethylstilbestrol phosphate compound (99mTc-DES-P) was examined by biodistribution studies on Wistar Albino rats. Statistical evaluation was performed using SPSS 13 program. The percentage (%) radiolabeling yield of 99mTc-DES-P and quality control studies were done by Thin Layer Radio Chromatography (TLRC). Results showed that, 99mTc-DES-P may be proposed as an imaging agent for ER enriched tumors such as uterus and prostate and their metastases in bones.

Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with 99mTc.

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM.

Bioavailability of 99mTc-paclitaxel-glucuronide (99mTc-PAC-G)

Abstract An antitumor agent paclitaxel (PAC) has been proved to be efficient in the treatment of breast and ovarian cancer. Glucuronic acid-derived paclitaxel compound [paclitaxel-glucuronide (PAC-G)] was enzymatically synthesized using microsome preparate separated from rat livers. The biodistribution mechanism of PAC-G in healthy female Albino Wistar rats has been investigated. The expected structure is confirmed according to LC/MS results, and the possible attachment is to C2-hydroxyl group. PAC-G was labeled with 99mTc and the radiochemical yield of radiolabeled compound (99mTc-PAC-G) was 98.0±02.74 (n=9). The range of the breast/blood and breast/muscle ratios is approximately between 3 and 35 in 240ߙmin. All these experimental studies indicate that 99mTc-PAC-G may potentially be used in breast tissue as an imaging agent.

Synthesis and Biological Evaluation of Bisphosphonate Compound Labeled with 99mTc(CO)3

In this study, radiolabeling of a bisphosphonate, alendronate (Alendronate sodium), was performed with the help of a bifunctional chelating agent. For that purpose, DTPA‐NHS (Diethylenetriaminepentaacetic acid dianhydride‐N‐hydroxysuccinimide) was synthesized with an esterification between DTPA and NHS. Combining the DTPA‐NHS ester with alendronate yields the DTPA‐Alendronate compound. The structure of synthesized compound was analyzed by 1H/13C/31P‐NMR and HPLC. After then, the labeling with [99mTc(CO)3]+ core of synthesized compound was provided. Performing quality controls of newly synthesized [99mTc(CO)3‐DTPA‐Alendronate] complex with thin layer radiochromatography (TLRC) and high‐performance liquid radiochromatography (HPLRC), the labeling yield was found as 99%. It was observed that the compound conserves its stability for 24 h in serum media. Biodistribution of the radiolabeled complex was performed on Wistar Albino rats to determine radiopharmaceutical potential of the [99mTc(CO)3‐DTPA‐Alendronate] complex. It is thought that the data gained from this study will contribute to the development of complexes with bisphosphonate.

In vivo biological evaluation of 131I radiolabeled-paclitaxel glucuronide (131I-PAC-G)

Abstract Paclitaxel (PAC) is a natural occurring diterpene alkoloid originally isolated from the bark of Taxus Brevifolia. It is one of the most important antitumor agents for clinical treatment of ovarian, breast non-small cell lung and prostate cancers. It is known that these types of cancer cells have high β-glucuronidase enzyme which can catalyze the hydrolysis of glucuronides. This is why the synthesis compounds which undergo glucuronidation come into question in the imaging and therapy of these cancer cells. The aim of current study is conjugation of glucuronic acid (G) to the starting substance PAC, labeling with 131I and to perform its in vivo biological evaluation. Glucuronic acid derived paclitaxel compound [paclitaxel-glucuronide (PAC-G)] was labeled with 131I using iodogen method. According to thin layer radio chromatography (TLRC) method, the radiochemical yield of 131I-PAC-G was 84.30 ± 7.40% (n=10). The biodistribution of 131I-PAC-G in healthy female and male Wistar Albino rats has been investigated. Imaging studies on male Balb-C mice were performed by using the Kodak FX PRO in vivo Imaging System. The range of the breast/blood, breast/muscle; ovary/blood, ovary/muscle ratios is approximately between 1.29 and 11.34 in 240 min, and between 0.71 and 8.24 in 240 min for female rats. The prostate/blood and prostate/muscle ratio is between 1.94 and 6.95 in 30 min for male rats. All these experimental studies indicate that 131I-PAC-G may potentially be used in breast, ovary and prostate tissues as an imaging agent. Also it is thought that 131I-PAC-G bears a theraphy potential because of the 131I radionuclide and can be improved with further investigations.

Synthesis, characterization and radiolabeling of folic acid modified nanostructured lipid carriers as a contrast agent and drug delivery system

Nanostructured lipid carriers (NLCs) are the new generation of solid lipid drug delivery systems. Their suitability as contrast agents for gamma scintigraphy is an attracting major attention. The aim of current study was to prepare surface modified nanostructured lipid carrier system for paclitaxel (PTX) with active targeting and imaging functions. In accordance with the purpose of study, PTX loaded nanostructured lipid carriers (NLCs) prepared, modified with a folate derivative and radiolabeled with technetium-99m tricarbonyl complex (99mTc(CO)3+). Cellular incorporation ratios of radiolabeled nanoparticles (99mTc(CO)3-PTX-NLC) were investigated in vitro on three cancer cell lines. Additionally in vivo animal studies conducted to evaluate biological behavior of 99mTc(CO)3-PTX-NLC on female Wistar Albino rats. Biodistribution results showed that the folate derivative modified 99mTc(CO)3-PTX-NLC had considerably higher uptake in folate receptor positive organs. The data obtained from present study could be useful in the design of biodegradable drug carriers of PTX and folate receptor based tumor imaging agents.

Radioiodine labeled CdSe/CdS quantum dots: Lectin targeted dual probes

Abstract CdSe/CdS quantum dots (QD) were synthesized and bioconjugated with Sambucus nigra agglutinin (SNA) lectin (Lec). Mannose triflate and cysteamine molecules (MTC) were also utilized to prepare MTC-QDs and MTC-QDs-Lec probes as well as Lec bound QDs. Afterwards; potential use of these nanoparticles as radiolabeled fluorescence nano-probes for the cell imaging studies has been investigated. Biological activities of 125I–, 125I-MTC-QDs, MTC-QDs- Lec-125I, QDs-Lec-125I and Lec-125I were examined on various cancer cell lines such as Caco-2, MCF-7 and A-549 in terms of cell incorporation. QDs-Lec-125I exhibited the highest cell incorporation on whole cell lines. In addition, the QDs-Lec-131I, was used for in vivo imaging. The whole body distribution of the radiolabeled QDs on New Zealand rabbits and Balb C mice were examined by taking dynamic and static images. Radioactivity cleared from the kidneys and the bladder, while significant amount radioactivity was retained in the heart and liver within 24 h.

A new approach to liquid penetrant inspection: radiolabeled QDots

Penetrant technique is a sensitive non-destructive testing (NDT) method for detecting and locating the presence of cracks in sample surface. Today, NDT is used in a wide range of industries including aerospace, biotechnology, defence, marine, oil–gas and energy plants. This work focuses on potential use of radiolabeled ZnS coated CdTe quantum dots (QDots) as a penetrant for liquid penetrant testing. The synthesized QDots as a precursor were tested for surface defects detection in welded joints. The experimental results show the highest activities were found in defects on the sample surface. These finding are consistent with the sample NDT inspection test report.

Thymidine kinase enzyme selective imaging radiopharmaceutical: 99mTc(CO)3-Ganciclovir

Abstract The aim of this study is to radiolabel ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore (99mTc(CO)3+) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with 99mTc(CO)3+. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The 99mTc(CO)3-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the 99mTc(CO)3-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group 99mTc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of 99mTc(CO)3-GCV could contribute to the development of a new HSV1-tk gene imaging agent.