In Vitro Investigation of Therapeutic Potential of Bare Magnetite (Fe3O4) Nanoparticles (≤100 ppm) on Hepatocellular Carcinoma Cells.

Significant ROS production capability of bare iron oxide nanoparticles in safe doses for healthy cells offers an interesting therapeutic window for cancer. In this context, the aim of the current study is to investigate therapeutic potential of the synthesized magnetite (Fe3O4) nanoparticles (~80 nm) as attractive vehicles for biomedical applications on hepatocellular carcinoma cells (HepG2). To investigate their time (0-72 h) and dose (0-100 µg/ml) dependent effect on physiological state (proliferation/ cytotoxicity) and mitochondrial activity of the tumor cells, xCELLigence system and MTT assay were used, respectively. Both 50 and 100 µg/ml of nanoparticle treatment induced significant (p < 0.01) increases in ROS production in HepG2 cells; however, ~4-day real-time cell analysis illustrated that all concentrations of the nanoparticles caused significant (p < 0.01) increases in proliferation of the tumor cells from 4 h after the treatment to the end of the analysis. While 50 and 100 µg/ml of nanoparticles caused significant deteriorations in the mitochondrial activity of the tumor cells in the case of 24 h-(p < 0.05 and p < 0.01, respectively) and 72 h-treatment (p < 0.01); 24 h-treatment of 100 µg/ml of nanoparticles and 72 h-treatment of 50 and 100 µg/ml of nanoparticles caused significant increases in the mitochondrial activity of the tumor cells (p < 0.01) under static magnetic field (1.35 T). Although the synthesized magnetite nanoparticles have not therapeutic potential alone on HepG2 cells in doses safe for healthy cells, the results of the current study are illuminating for future magnetite nanoparticle-based biomedical applications and combination cancer therapy containing magnetite nanoparticles.

Sensitization of cisplatin-resistant ovarian cancer cells by magnetite iron oxide nanoparticles: an in vitro study.

Aim: To investigate potential of magnetite iron oxide nanoparticles (MION) to sensitize cisplatin-resistant ovarian cancer cells to cisplatin, which to the best of found knowledge has not been reported previously. Materials & methods: MION with a diameter of approximately 20 nm were synthesized, and characterized using Fourier transform infrared spectroscopy, powder x-ray diffraction and particle size analyzer. Results: The synthesized MION have increased reactive oxygen species levels and decreased glutathione levels in cisplatin-resistant ovarian cancer cells (OVCAR-3 and SKOV-3). Using MTT, capsase-3 activity and live/dead assays, capability of the synthesized MION to sensitize cisplatin-resistant ovarian cancer cells has been illustrated. Conclusion: Thus, for further investigations, the synthesized MION can be considered as a potent agent enabling much more effective cisplatin-based therapies for ovarian cancer.

A microfluidic 3D hepatocyte chip for hepatotoxicity testing of nanoparticles.

Aim: To develop a practical microfluidic 3D hepatocyte chip for hepatotoxicity testing of nanoparticles using proof of concept studies providing first results of the potential hepatotoxicity of superparamagnetic iron oxide nanoparticles (SPION) under microfluidic conditions. Methods: A microfluidic 3D hepatocyte chip with three material layers, which contains primary rat hepatocytes, has been fabricated and tested using different concentrations (50, 100 and 200 µg/ml) of SPION in 3-day (short-term) and 1-week (long-term) cultures. Results: Compared with standard well plates, the hepatocyte chip with flow provided comparable viability and significantly higher liver-specific functions, up to 1 week. In addition, the chip recapitulates the key physiological responses in the hepatotoxicity of SPION. Conclusion: Thus, the developed 3D hepatocyte chip is a robust and highly sensitive platform for investigating hepatotoxicity profiles of nanoparticles.

Dose-, treatment- and time-dependent toxicity of superparamagnetic iron oxide nanoparticles on primary rat hepatocytes.

AIM: As a first study in literature, to investigate concentration-dependent (0-400 µg/ml) and exposure-dependent (single dosing vs cumulative dosing) effects of superparamagnetic iron oxide nanoparticles (d = 10 nm) on primary rat hepatocytes in a time-dependent manner. MATERIALS & METHODS: Sandwich-cultured hepatocyte model was used to evaluate viability, hepatocyte specific functions and reactive oxygen species level. RESULTS: In terms of all parameters, generally statistically more significant effects were observed in a concentration- and time-dependent manner. In terms of hepatocyte-specific functions, cumulative dosing caused significantly (p < 0.05) more deleterious effects at 48th hour. CONCLUSION: A combination of various biomarkers should be employed for the evaluation of the effect of superparamagnetic iron oxide nanoparticles on liver, and each biomarker should be analyzed in a time- and exposure-dependent manner.

Strategies Targeting DNA Topoisomerase I in Cancer Chemotherapy: Camptothecins, Nanocarriers for Camptothecins, Organic Non-Camptothecin Compounds and Metal Complexes.

Topoisomerase I (Topo I) is a nuclear enzyme engaged in adjustment of DNA topological structure during cell cycle by cleaving and reannealing one of the two strands of the DNA double helix. Inhibition of this enzyme results in DNA strand breaks, ultimately leads to apoptosis and cell death; additionally it is in raised level in solid tumors contrasted with healthy tissues. Consequently, Topo I has a great potential as a target for the treatment of tumors. Although significant anti-tumor activity of first Topo I inhibitor, camptothecin (CPT), was observed on colon, lung, ovarian, breast, liver, pancreas and stomach cancers, CPT and its clinical derivatives (topotecan and irinotecan) have several restrictions. In addition to their low water solubility and cell resistance to CPTs, lactone ring opening causes a reduction in cytotoxic activity and severe side effects in physiological conditions (pH: 7.4, 37°C). Although numerous efficient nano drug delivery systems were developed for CPT and its derivatives to compensate the handicaps of these compounds, none of them has been approved so far. On the other hand, organic non-CPT compounds have been searched; indolocarbazoles, indenoisoquinolines and dibenzonaphthyridines have been applied to clinical development. Especially, indenoisoquinolines and dibenzonaphthyridines have favorable characteristics compared to CPTs: They are chemically stable; they have the ability to overcome cell resistance; they stabilize enzyme-DNA cleavage complexes more persistently. In addition to the approaches based on organic compounds, recently some metal complexes (e.g., platinum, gold, copper, cobalt, zinc, vanadium, ruthenium) have also been reported as inhibitors of Topo I. This review will discuss the whole aspects of strategies targeting Topo I in cancer chemotherapy from past to the recent progresses.

Recombinant plasmid-based quantitative Real-Time PCR analysis of Salmonella enterica serotypes and its application to milk samples.

The aim of the current study was to develop, a new, rapid, sensitive and quantitative Salmonella detection method using a Real-Time PCR technique based on an inexpensive, easy to produce, convenient and standardized recombinant plasmid positive control. To achieve this, two recombinant plasmids were constructed as reference molecules by cloning the two most commonly used Salmonella-specific target gene regions, invA and ttrRSBC. The more rapid detection enabled by the developed method (21 h) compared to the traditional culture method (90 h) allows the quantitative evaluation of Salmonella (quantification limits of 10(1)CFU/ml and 10(0)CFU/ml for the invA target and the ttrRSBC target, respectively), as illustrated using milk samples. Three advantages illustrated by the current study demonstrate the potential of the newly developed method to be used in routine analyses in the medical, veterinary, food and water/environmental sectors: I--The method provides fast analyses including the simultaneous detection and determination of correct pathogen counts; II--The method is applicable to challenging samples, such as milk; III--The method's positive controls (recombinant plasmids) are reproducible in large quantities without the need to construct new calibration curves.

Effects of in-office and at-home bleaching on human enamel and dentin: an in vitro application of Fourier transform infrared study.

In-office and at-home bleaching techniques are widely used methods for the whitening of teeth. However, the safety of these techniques has not been clarified yet. The aim of the current study is to investigate the in-office- and at-home-bleaching-induced structural and quantitative changes in human enamel and dentin at the molecular level, under in vitro conditions. The Fourier transform mid-infrared (mid-FT-IR) spectroscopic technique was used to monitor bleaching-induced structural changes. Band frequency and intensity values of major absorptions such as amide A, amide I, phosphate (PO(4)), and carbonate (CO(3)(-2)) bands, for treatment groups and control, were measured and compared. The results revealed that both procedures have negligible effects on dentin constituents. In office-bleached enamel, in addition to demineralization, a decrease in protein and polysaccharide concentrations, mineral-to-protein ratio, and the strength of hydrogen bonds around NH groups, as well as a change in protein secondary structure were observed. The protein structure changed from beta-sheet to random coil, which is an indication of protein denaturation. However, no significant variations were observed for at-home bleached enamel. The control, at-home, and in-office bleached enamel samples were differentiated with a high accuracy using cluster analysis based on FT-IR data. This study revealed that office bleaching caused deleterious alterations in the composition and structure of enamel that significantly affected the crystallinity and mineralization of the tissue. Therefore, at-home bleaching seems to be much safer than in-office bleaching in terms of molecular variations.