Cell Death and Intracellular Distribution of Hematoporphyrin in a KB Cell Line

Application of Multi-Layered Temperature-Responsive Polymer Brushes Coating on Titanium Surface to Inhibit Biofilm Associated Infection in Orthopedic Surgery

Infection associated with biomedical implants remains the main cause of failure, leading to reoperation after orthopedic surgery. Orthopedic infections are characterized by microbial biofilm formation on the implant surface, which makes it challenging to diagnose and treat. One potential method to prevent and treat such complications is to deliver a sufficient dose of antibiotics at the onset of infection. This strategy can be realized by coating the implant with thermoregulatory polymers and triggering the release of antibiotics during the acute phase of infection. We developed a multi-layered temperature-responsive polymer brush (MLTRPB) coating that can release antibiotics once the temperature reaches a lower critical solution temperature (LCST). The coating system was developed using copolymers composed of diethylene glycol methyl ether methacrylate and 2-hydroxyethyl methacrylate by alternatively fabricating monomers layer by layer on the titanium surface. LCST was set to the temperature of 38-40 °C, a local temperature that can be reached during infection. The antibiotic elution characteristics were investigated, and the antimicrobial efficacy was tested against S. aureus species (Xen29 ATCC 29 213) using one to four layers of MLTRPB. Both in vitro and in vivo assessments demonstrated preventive effects when more than four layers of the coating were applied, ensuring promising antibacterial effects of the MLTRPB coating.

Metabonomic Variation of Exopolysaccharide from Rhizopus nigricans on AOM/DSS-Induced Colorectal Cancer in Mice

BACKGROUND

Colorectal cancer (CRC), which occurs at the junction of the rectum and sigmoid colon, is a common malignancy associated with poor prognosis and high mortality worldwide. The exopolysaccharide (EPS1-1), isolated from the fermentation broth of Rhizopus nigricans (R. nigricans), has been reported to possess anti-CRC properties. However, the metabolic alterations caused by azoxymethane (AOM) and dextran sulfate sodium (DSS) are still unknown.

METHODS

In the present study, a mice colon cancer model was established by treatment with AOM/DSS. LC-MS/MS-based metabolomics studies were performed to analyze metabolic alterations at the tissue level. Partial least squares discriminant analysis (PLS-DA) was used to identify differentially expressed metabolites.

RESULTS

Nineteen distinct metabolites were identified that were associated with disruptions in the following pathways: biosynthesis of unsaturated fatty acids, pyrimidine metabolism, phenylalanine metabolism, fatty acid metabolism, folate biosynthesis, and inositol phosphate metabolism. Furthermore, six significantly altered metabolites were involved in these six pathways. Compared with the Model group, the expression of cytosine, deoxyuridine, 20-hydroxy-leukotriene E4, and L-homocysteic acid was lower, whereas that of 2-dehydro-3-deoxy-6-phospho-D-gluconic acid and hematoporphyrin was higher in the EPS1-1 group.

CONCLUSION

The results of multivariate statistical analysis demonstrate a promising application of the above metabolites by EPS1-1 in CRC therapy. Deeper understanding of the related mechanism warrants further investigation.

Antibacterial application of covalently immobilized photosensitizers on a surface

Singlet oxygen produced by irradiating photosensitizers (PSs) can be used to kill pathogens during water treatment. Chemical immobilization of the PSs on surfaces can maintain their disinfection function long-term. In this study, two model PSs (rose bengal (RB) and hematoporphyrin (HP)) were immobilized on a glass surface using a silane coupling agent with an epoxide group, and their antibacterial properties were analyzed. Fourier transform infrared spectroscopy demonstrated that a covalent bond formed between the epoxide group and hydroxyl group in the PSs. A large proportion of the immobilized PSs (approximately 50%) was active in singlet oxygen production, which was evidenced by a comparative analysis with free PSs. RB was more effective at producing singlet oxygen than HP. The immobilized PSs were durable in terms of repeated use. On the other hand, singlet oxygen produced by the PSs was effective at killing bacteria, mostly for Gram-positive bacteria (> 90% death for 2 h of irradiation), by damaging the cell membrane. The preferable antibacterial property against Gram-positive bacteria compared with that against Gram-negative bacteria suggested efficient penetrability of singlet oxygen across the cell membrane, which led to cell death. Taken together, it was concluded that immobilization of PSs on surfaces using the silane coupling agent proposed in this study was effective at killing Gram-positive bacteria by forming singlet oxygen.

Suppression of T24 human bladder cancer cells by ROS from locally delivered hematoporphyrin-containing polyurethane films

Systemic injection of a photosensitizer is a general method in photodynamic therapy, but it has complications due to the unintended systemic distribution and remnants of photosensitizers. This study focused on the possibility of suppressing luminal proliferative cells by excessive reactive oxygen species from locally delivered photosensitizer with biocompatible polyurethane, instead of the systemic injection method. We used human bladder cancer cells, hematoporphyrin as the photosensitizer, and polyurethane film as the photosensitizer-delivering container. The light source was a self-made LED (510 nm, 5 mW cm-2) system. The cancer cells were cultured on different doses of hematoporphyrin-containing polyurethane film and irradiated with LED for 15 minutes and 30 minutes each. After irradiating with LED and incubating for 24 hours, cell viability analysis, cell cycle analysis, apoptosis assay, intracellular and extracellular ROS generation study and western blot were performed. The cancer cell suppression effects of different concentrations of the locally delivered hematoporphyrin with PDT were compared. Apoptosis dominant cancer cell suppressions were shown to be hematoporphyrin dose-dependent. However, after irradiation, intracellular ROS amounts were similar in all the groups having different doses of hematoporphyrin, but these values were definitely higher than those in the control group. Excessive extracellular ROS from the intended, locally delivered photosensitizer for photodynamic treatment application had an inhibitory effect on luminal proliferative cancer cells. This method can be another possibility for PDT application on contactable or attachable lesions.

Raman microspectroscopy of Hematoporphyrins. Imaging of the noncancerous and the cancerous human breast tissues with photosensitizers

Raman microspectroscopy combined with fluorescence were used to study the distribution of Hematoporphyrin (Hp) in noncancerous and cancerous breast tissues. The results demonstrate the ability of Raman spectroscopy to distinguish between noncancerous and cancerous human breast tissue and to identify differences in the distribution and photodegradation of Hematoporphyrin, which is a photosensitizer in photodynamic therapy (PDT), photodynamic diagnosis (PDD) and photoimmunotherapy (PIT) of cancer. Presented results show that Hematoporphyrin level in the noncancerous breast tissue is lower compared to the cancerous one. We have proved also that the Raman intensity of lipids and proteins doesn't change dramatically after laser light irradiation, which indicates that the PDT treatment destroys preferably cancer cells, in which the photosensitizer is accumulated. The specific subcellular localization of photosensitizer for breast tissues samples soaked with Hematoporphyrin was not observed.

Psoralea glandulosa as a potential source of anticancer agents for melanoma treatment

With the aim of identifying novel agents with antigrowth and pro-apoptotic activity on melanoma cancer, the present study was undertaken to investigate the biological activity of the resinous exudate of aerial parts from Psoralea glandulosa, and its active components (bakuchiol (1), 3-hydroxy-bakuchiol (2) and 12-hydroxy-iso-bakuchiol (3)) against melanoma cells (A2058). In addition, the effect in cancer cells of bakuchiol acetate (4), a semi-synthetic derivative of bakuchiol, was examined. The results obtained show that the resinous exudate inhibited the growth of cancer cells with IC50 value of 10.5 μg/mL after 48 h of treatment, while, for pure compounds, the most active was the semi-synthetic compound 4. Our data also demonstrate that resin is able to induce apoptotic cell death, which could be related to an overall action of the meroterpenes present. In addition, our data seem to indicate that the apoptosis correlated to the tested products appears, at least in part, to be associated with an increase of reactive oxygen species (ROS) production. In summary, our study provides the first evidence that P. glandulosa may be considered a source of useful molecules in the development of analogues with more potent efficacy against melanoma cells.

Cell proliferation and cell cycle alterations in oesophageal p53-mutated cancer cells treated with cisplatin in combination with photodynamic therapy

OBJECTIVES

The major goal of anti-cancer therapies is selective destruction of tumour cells with minimum side effects on normal cells. Towards this aim, combination of different therapeutic modalities has been evaluated for improving control of neoplastic diseases and quality of life for the patient. Photodynamic therapy (PDT) is a procedure for treatment of various types of cancer, but its combination with other established treatments has not been evaluated in detail. We have used KYSE-510 cells from a human oesophageal carcinoma as an in vitro model to investigate whether cisplatin (CDDP) could be combined with PDT to increase cell death with respect to single treatments.

MATERIALS AND METHODS

p53-mutated KYSE-510 cells were treated with CDDP alone or in combination with PDT. Analyses of cell viability, cell cycle progression and apoptosis induction were carried out at specific times after treatments.

RESULTS

Decrease in cell viability, cell cycle arrest at the G(2)/M- and S-phases boundary, and apoptosis induction were observed after single and combined treatments.

CONCLUSIONS

Our results show that low CDDP doses (0.25-1 microm) induce cell mortality and cell cycle perturbation, which were more evident when given in combination with PDT, but in contrast to work of other authors no synergistic activity was found. Apoptosis occurred via intrinsic pathways in treated cells, although it did not represent the predominant mode of cell death.