Influential Factors in the Efficacy of Hemoporfin-Mediated Photodynamic Therapy for Port-wine Stains.

Hemoporfin-mediated photodynamic therapy (HMME-PDT) is commonly used in the treatment of port-wine stains (PWS). However, the influential factors for the efficacy of the treatment are not well defined. This study intends to observe the influential factors for the efficacy of HMME-PDT in the treatment of port-wine stains (PWS). A total of 551 patients with PWS of head and neck was enrolled in this retrospective study. Further screening the patients of facial PWS, 484 patients were chosen. Patients were treated with HMME-PDT. All patients received 1~3 sessions of treatment with 2~3-month intervals. We photographed the lesions before each session and 2~3 months after the last session. Ages, sessions, lesion subtypes, and previous treatment history were related to the response of HMME-PDT (P =0.032, P<0.001, P=0.012, P=0.003 respectively). Treatment sessions were the independent factor correlated with efficacy after 3 sessions of treatment. Patients with no treatment history targeting PWS showed higher efficacy than those were treated with laser or other photodynamic treatment (P<0.05). The efficacy was higher by increasing the sessions of treatment. The efficacy was higher for lesion on maxillary prominence area and mandibular prominence area that on frontonasal prominence area and optic vesicle area (P<0.05). HMME-PDT is an effective in the treatment of PWS. Patients received no previous treatment for PWS, total treatment sessions and lesion on maxillary prominence area and mandibular prominence area are positive factors.

Hematoporphyrin monomethyl ether mediated photodynamic therapy inhibits oral squamous cell carcinoma by regulating the P53-miR-21-PDCD4 axis via singlet oxygen.

The objective of this study was to determine the mechanism and effect of hematoporphyrin monomethyl ether mediated photodynamic therapy (HMME-PDT) on oral squamous cell carcinoma (OSCC). Human OSCC CAL-27 cells were randomly divided into four groups: control group, HMME group, laser group, and HMME-PDT group. Cell viability was detected by the CCK-8 method. Cell cycle distribution was evaluated by flow cytometry. GEO database was used to screen differentially expressed microRNAs (DEMs), and TCGA database was performed to verify DEM expression in OSCC and normal tissues. The effects of HMME-PDT on DEM expression were assayed by real-time PCR, and the expressions of miRNAs target genes were measured by western blot. Fluorescence probes were used to determine the production of singlet oxygen (1O2). Compared with the other three groups, HMME-PDT dramatically inhibited CAL-27 cell proliferation and induced G0/G1 cycle arrest. The expressions of miR-21 and miR-155 were significantly upregulated in OSCC. HMME-PDT downregulated the expression of miR-21 but had no obvious effect on miR-155. HMME-PDT remarkably upregulated the levels of P53 and miR-21 target proteins, such as PDCD4, RECK, and SPRY2. 1O2 was generated during HMME-PDT, and inhibition of 1O2 production could reverse the regulation of HMME-PDT on P53, miR-21, and its target proteins, thus restoring cell viability. HMME-PDT can significantly inhibit the growth of OSCC cells, and the mechanism of this effect is related to the regulation of the P53-miR-21-PDCD4 axis via 1O2 induced by HMME-PDT.

Hematoporphyrin monomethyl ether mediated sonodynamic antimicrobial chemotherapy on porphyromonas gingivalis in vitro.

This study aimed to evaluate the efficacy of hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic antimicrobial chemotherapy (SACT) on Porphyromonas gingivalis (P. gingivalis). P. gingivalis (ATCC 33277) was used in the present study. The bacterial suspension was randomly divided into five groups: Group 1 was incubated for 2 h in the dark with HMME in various concentrations (10, 20, 30 and 40 µg/mL). Then exposed to 1 MHz ultrasound frequency with 3 W/cm2 ultrasound intensity for 10 min. Group 2 was incubated with 40 µg/mL HMME and then irradiated with 2, 4, 6, 8 and 10 min ultrasonic time. Group 3 received different HMME concentration (10, 20, 30 and 40 µg/mL) treatment alone with no ultrasound as the HMME control group. Group 4 received ultrasound treatment alone in different ultrasonic time (2, 4, 6, 8 and 10 min) with no HMME as the ultrasound control group. Group 5 received no treatment as the no treatment control group. After the SACT, the bactericidal effect was determined by the colony forming unit assay. The intracellular content of reactive oxygen species (ROS) was detected using the laser scanning confocal microscope based on DCFH-DA. 4.7 lg reduction in CFU, When P. gingivalis was treated with ultrasound (3 W/cm2 for 10 min) at 40 µg/mL HMME concentration (P < 0.01). The intracellular ROS in SDT group had a significant difference in comparison with the no treatment control group (P < 0.01). HMME mediated SACT can be a potential antibacterial therapy to significantly inhibit P. gingivalis growth.

Hematoporphyrin monomethyl ether-mediated photodynamic therapy inhibits the growth of keloid graft by promoting fibroblast apoptosis and reducing vessel formation.

Photodynamic therapy (PDT) has been shown to significantly inhibit fibroblast activity. However, the effect of PDT mediated by the photosensitizer hematoporphyrin monomethyl ether (HMME) on keloids is not known well. The aim of our study was to examine the efficacy of HMME-PDT in cellular and animal models of keloids. Keloid fibroblasts (KFbs) were isolated from human keloid specimens and the proliferation, invasion, and migration of KFbs after HMME-PDT treatment was examined in vitro. Apoptosis in cells was measured by flow cytometry. Cysteinyl aspartate specific proteinase 3 (Caspase3) expression was determined by immunofluorescence staining and western blot. HMME-PDT inhibited KFbs proliferation, invasion, migration, increased apoptosis rate and enhanced caspase3 and cleaved caspase3 expression. The keloid graft transplantation was performed by using nude mice. The growth of the graft was monitored every third day. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) mRNA expression were detected by quantitative real time PCR. It was observed that HMME-PDT attenuated graft growth and reduced vessel density in the keloid grafts. However, HMME-PDT did not alter IL-6 and TNF-α mRNA expression in the keloid grafts. Moreover, HMME-PDT suppressed transforming growth-ß1 (TGF-ß1) and small phenotype and Drosophila Mothers Against Decapentaplegic 3 (Smad3) expression in both KFbs and keloid grafts. Collectively, the evidence suggests that HMME-PDT inhibits the growth of the keloid graft by promoting the apoptosis of fibroblasts and reducing vessel formation of the keloid graft.

Bactericidal effects of hematoporphyrin monomethyl ether-mediated blue-light photodynamic therapy against Staphylococcus aureus.

The implementation of photodynamic therapy (PDT) usually uses red light as the excitation source to obtain a deeper penetration depth. However, for some superficial infectious diseases, using red-light PDT may damage the normal tissues underneath. If we choose a shorter wavelength light, then the effect of PDT can be limited to the superficial region. This study assessed the effect of blue-light PDT against Staphylococcus aureus. The absorption of hematoporphyrin monomethyl ether (HMME) by S. aureus was investigated using fluorescence spectroscopy. The bactericidal effects of HMME, light alone, and PDT using blue light (405 nm) on S. aureus were studied. The results indicate that the HMME uptake by S. aureus rapidly reached a certain value, then steadily increased with time in the range of 0-80 min, and thenreached a plateau at 80 min before a slow decline afterward. Without light irradiation, less than 2 µg ml-1 HMME showed no bactericidal effect on S. aureus. Without HMME, blue-light at a power density of 20 mW cm-2 had no significant bactericidal effect for 0.5 min to 10 min. When 2 µg ml-1 of HMME was combined with blue-light (20 mW cm-2), the bactericidal effect showed a reduction of 3 log10 with the extension of irradiation time. These results demonstrated that bacteria have the ability to absorb HMME, and HMME-mediated blue-light PDT can effectively kill the bacteria, which laid the foundation for blue-light PDT as a non-invasive treatment for superficial infectious diseases.

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.

Effect of 410 nm photodynamic therapy with hemoporfin on the expression of vascular endothelial growth factor (VEGF) in cultured human vascular endothelial cells.

Photodynamic therapy (PDT) is considered an effective alternative for the treatment of port-wine stains (PWS) using hemoporfin (hematoporphyrin monomethyl ether, HMME), a novel photosensitizer with better efficacy and lower recurrence. Vascular endothelial growth factor (VEGF) plays an important role in the development of PWS. Therefore, we conducted this study to investigate the effect of HMME-PDT on VEGF expression. Human vascular endothelial cells (HUVECs) were treated with different doses of HMME and irradiated with 410-nm light emitting-diode (LED) light. To assess cell viability, CCK-8 assays were performed. At 48 h after PDT, the expression of VEGF/VEGF receptor (VEGFR) mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). Measurement of VEGF protein was carried out using western blotting assays. Cell viability was significantly inhibited after HMME-PDT and was dose-dependent within a certain range. HMME-PDT decreased secretion of VEGF 48 h after irradiation in HUVECs as compared to controls. The downregulation of VEGF and VEGFR mRNA as well as VEGF protein expression was more significant in the high HMME concentration group (4 µg/mL) than in the lower concentration group (2 µg/mL). Our outcomes provide evidence, that HMME-PDT can downregulate VEGF expression in cultured HUVECs and may explain the efficacy of hemoporfin PDT for PWS treatment.

Photodynamic inactivation of planktonic cultures and Streptococcus mutans biofilms for prevention of white spot lesions during orthodontic treatment: An in vitro investigation.

INTRODUCTION: This study evaluated the efficacy of photodynamic inactivation (PDI) with hematoporphyrin IX (H) and modified hematoporphyrin IX (MH) at 10 µmol/L, using a blue light-emitting diode (LED), fluence of 75 J/cm,2 over planktonic cultures and biofilm of Streptococcus mutans (UA 159). METHODS: Suspensions containing 107 cells/mL were tested under different experimental conditions: a) H and LED (H+L+), b) MH and LED (MH+L+), c) only LED (P-L+), d) only H (H+L-), e) only MH (MH+L-), and f) control group, no LED or photosensitizer treatment (P-L-). The study also evaluated the effect of PDI on S mutans biofilm on metallic or ceramic brackets bonded on specimens of human teeth. The strains were seeded onto Mitis salivarius-bacitracin-sacarose agar to determine the number of colony-forming units. RESULTS: H and MH under LED irradiation were effective on planktonic cultures (P <0.0001). H and MH (H+L+ and MH+L+) caused a reduction of 3.80 and 6.78 log10 CFU/mL. PDI with the use of H or MH and LED exerted a strong antimicrobial effect over S mutans showing 54% and 100% reduction, respectively. PDI on S mutans biofilm on metallic and ceramic brackets with the use of H was not effective (P = 0.0162, P = 0.1669), however, MH caused a significant reduction of 44% and 53% of the cell count on metallic and ceramic brackets, respectively (P = 0.0020, P = 0.004). CONCLUSIONS: In vitro planktonic cultures with the use of H or MH and LED exerted significant antimicrobial activity. No effect was observed on S mutans biofilm on either bracket type with the use of H, MH showed better results, suggesting a promising use against dental caries and white spot lesions.

Combined Phycocyanin and Hematoporphyrin Monomethyl Ether for Breast Cancer Treatment via Photosensitizers Modified Fe3O4 Nanoparticles Inhibiting the Proliferation and Migration of MCF-7 Cells.

Photodynamic therapy (PDT), combining the laser and photosensitizers to kill tumor cells, has the potential to address many current medical requirements. In this study, magnetic Fe3O4 nanoparticles were first employed as cores and modified with oleic acid (OA) and 3-triethoxysilyl-1-propanamine. Then, the photosensitizers phycocyanin (PC) and hematoporphyrin monomethyl ether (HMME), which might be able to stimulate the cell release of reactive oxygen species after the irradiation of a near-infrared (NIR) laser, were grafted on the surface of such nanoparticles. Our results revealed the high-efficiency inhibition of breast cancer MCF-7 cells growing upon near-infrared irradiation both in vitro and in vivo. Furthermore, it was the synergy between the natural photosensitizers PC and the synthetic photosensitizers HMME that deeply influenced such inhibition compared to the groups that used either of these medicines alone. To utilize the combination of different photosensitive agents, our study thus provides a new strategy for breast cancer treatment.

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.

Cellular Pharmacology of Palladinum(III) Hematoporphyrin IX Complexes: Solution Stability, Antineoplastic and Apoptogenic Activity, DNA Binding, and Processing of DNA-Adducts.

Two paramagnetic PdIII complexes of hematoporphyrin IX ((7,12-bis(1-hydroxyethyl)-3,8,13,17-tetramethyl-21H-23H-porphyn-2,18-dipropionic acid), Hp), namely a dinuclear one [PdIII2(Hp-3H)Cl3(H2O)5]·2PdCl2, Pd1 and a mononuclear metalloporphyrin type [PdIII(Hp-2H)Cl(H2O)]·H2O, Pd2 have been synthesized reproducibly and isolated as neutral compounds at different reaction conditions. Their structure and solution stability have been assayed by UV/Vis and EPR spectroscopy. The compounds researched have shown in vitro cell growth inhibitory effects at micromolar concentration against a panel of human tumor cell lines. A DNA fragmentation test in the HL-60 cell line has indicated that Pd1 causes comparable proapoptotic effects with regard to cisplatin but at substantially higher concentrations. Pd1 and cisplatin form intra-strand guanine bis-adducts as the palladium complex is less capable of forming DNA adducts. This demonstrates its cisplatin-dissimilar pharmacological profile. The test for efficient removal of DNA-adducts by the NER synthesis after modification of pBS plasmids with either cisplatin or Pd1 has manifested that the lesions induced by cisplatin are far better recognized and repaired compared those of Pd1. The study on the recognition and binding of the HMGB-1 protein to cisplatin or Pd1 modified DNA probes have shown that HMG proteins are less involved in the palladium agent cytotoxicity.

Synthesis of 2-morpholinetetraphenylporphyrins and their photodynamic activities.

A series of 2-morpholinetetraphenylporphyrins functionalized with various substituents (Cl, Me, MeO group) at 4-phenyl position were prepared via nucleophilic substitution of 2-nitroporphyrin copper derivatives with morpholine by refluxing under a nitrogen atmosphere and then demetalization. Their basic photophysical properties, intracellular localization, cytotoxicities in vitro and in vivo were also investigated. All synthesized photosensitizers exhibited longer maxima absorption wavelengths than Hematoporphyrin monomethyl ether (HMME). They showed low dark cytotoxicity compared with that of HMME and were more phototoxic than HMME against Eca-109 cells in vitro. M3 also exhibited better photodynamic antitumor efficacy on BALB/c nude mice at a lower concentration. Therefore, M3 is a promising antitumor photosensitizer in photodynamic therapy application.

Haematoporphyrin monomethyl ether-mediated photodynamic inactivation of the biofilms produced by standard and fluconazole-resistant Candida albicans strains.

BACKGROUND: The use of photodynamic antimicrobial chemotherapy (PACT) to treat localized Candida infections is an emerging and promising therapeutic approach. AIM: To assess the photodynamic inactivation (PDI) efficacy of haematoporphyrin monomethyl ether (HMME) on the biofilms produced by standard (ATCC 10231) and fluconazole-resistant Candida albicans strains. METHODS: The PDI efficacy was evaluated by incubating C. albicans biofilms with 0.01-10 µmol/L HMME for 30 min in the dark, followed by irradiation with 400-800 nm light for 30 min. RESULTS: HMME inactivated the biofilms in a concentration-dependent manner in the presence of light, but it exhibited no significant toxicity without light. After treatment with 10 µmol/L HMME and irradiation for 30 min, 2.47 and 3.26 log10 reductions in survival were achieved for C. albicans ATCC 10231 and fluconazole-resistant C. albicans, respectively. CONCLUSIONS: Biofilms formed by the two strains were sensitive to HMME-mediated PDI.

Photocytotoxicity of a cyanine dye with two chromophores toward melanoma and normal cells.

BACKGROUND: Due to high optical absorption, triplet quantum yield and affinity to biological structures bichromophoric cyanine dyes (BCDs) can be considered promising sensitizers for application in photodynamic therapy (PDT). In this work, we report on the study of the BCD photocytotoxicity toward melanoma and normal cells in comparison with that of commercial photosensitizer Photogem®. METHODS: The cytotoxic and phototoxic effects were measured by standard tests of cell viability. The drug uptake was obtained by the flow cytometry and optical absorption techniques. The BCD intracellular distribution was obtained by the fluorescence image microscopy using specific organelle markers. RESULTS: Both drugs demonstrated increased cytotoxicity under irradiation, while in darkness their cytotoxic effect at concentrations lower than 20 µM after 24 h of incubation did not exceed 20%. For 5 h of incubation, BCD photocytotoxicity in relation to melanoma cells reached 100% already at concentrations below 5 µM, while for normal cells the effect did not exceed 70% even for the 20 µM concentration. It is shown that BCD penetrates into the cells and is located predominantly in perinuclear cytoplasmic structures. CONCLUSIONS: The BCD photosensitizing characteristics appear more adequate for application in PDT than that of the actually applied commercial photosensitizer Photogem®. Higher light absorption by BCD in the near IR region and its preferential localization in mitochondria can explain its high photocytotoxicity. GENERAL SIGNIFICANCE: BCD can be considered as a new promising photosensitizer class for cancer PDT.

A multi-functional nanoplatform for tumor synergistic phototherapy.

Phototherapy, which mainly includes photothermal treatment (PTT) and photodynamic treatment (PDT), is a photo-initiated, noninvasive and effective approach for cancer treatment. The high accumulation of photosensitizers (PSs) in a targeted tumor is still a major challenge for efficient light conversion, to generate reactive oxygen species (ROS) and local hyperthermia. In this study, a simple and efficient hyaluronic acid (HA)-modified nanoplatform (HA-TiO2@MWCNTs) with high tumor-targeting ability, excellent phototherapy efficiency, low light-associated side effects and good water solubility was developed. It could be an effective carrier to load hematoporphyrin monomethyl ether (HMME), owing to the tubular conjugate structure. Apart from this, the as-prepared TiO2@MWCNTs nanocomposites could also be used as PSs for tumor PTT and PDT. Those results in vitro and in vivo showed that the anti-tumor effect of this system-mediated PTT/PDT were significantly better than those of single treatment manner. In addition, this drug delivery system could realize high ratio of drug loading, sustained drug release, prolonged circulation in vivo and active targeted accumulation in tumor. These results suggest that HA-TiO2@MWCNTs/HMME has high potential for tumor synergistic phototherapy as a smart theranostic nanoplatform.

Photodynamic inactivation of antibiotic-resistant bacteria and biofilms by hematoporphyrin monomethyl ether.

The worldwide increase in bacterial antibiotic resistance has led to a search for alternative antibacterial therapies. A promising approach to killing antibiotic-resistant bacteria is photodynamic antimicrobial chemotherapy, which uses light in combination with a photosensitizer to induce a phototoxic reaction. We evaluated the photodynamic inactivation (PDI) efficiency of hematoporphyrin monomethyl ether (HMME) on antibiotic-resistant bacteria and biofilms. HMME exhibited no significant dark toxicity and provided dose-dependent inactivation of antibiotic-resistant bacteria and biofilms. After incubation with 100-µM HMME and irradiation with 72-J cm(-2) white light, 4.19-7.59 log10 reductions in survival were achieved in planktonic suspension. Antibiotic-resistant strains were as susceptible to PDI in biofilms as in planktonic suspensions, but the inactivation of bacterial cells in biofilms was attenuated. In addition, gram-positive bacterial strains and biofilms were more susceptible than gram-negative strains and biofilms to the PDI effect of HMME. Thus, HMME is a promising photosensitizer for the treatment of infectious diseases caused by antibiotic-resistant bacteria, especially gram-positive bacteria.

Size-Dependent Photodynamic Anticancer Activity of Biocompatible Multifunctional Magnetic Submicron Particles in Prostate Cancer Cells.

In this study, newly designed biocompatible multifunctional magnetic submicron particles (CoFe2O4-HPs-FAs) of well-defined sizes (60, 133, 245, and 335 nm) were fabricated for application as a photosensitizer delivery agent for photodynamic therapy in cancer cells. To provide selective targeting of cancer cells and destruction of cancer cell functionality, basic cobalt ferrite (CoFe2O4) particles were covalently bonded with a photosensitizer (PS), which comprises hematoporphyrin (HP), and folic acid (FA) molecules. The magnetic properties of the CoFe2O4 particles were finely adjusted by controlling the size of the primary CoFe2O4 nanograins, and secondary superstructured composite particles were formed by aggregation of the nanograins. The prepared CoFe2O4-HP-FA exhibited high water solubility, good MR-imaging capacity, and biocompatibility without any in vitro cytotoxicity. In particular, our CoFe2O4-HP-FA exhibited remarkable photodynamic anticancer efficiency via induction of apoptotic death in PC-3 prostate cancer cells in a particle size- and concentration-dependent manner. This size-dependent effect was determined by the specific surface area of the particles because the number of HP molecules increased with decreasing size and increasing surface area. These results indicate that our CoFe2O4-HP-FA may be applicable for photodynamic therapy (PDT) as a PS delivery material and a therapeutic agent for MR-imaging based PDT owing to their high saturation value for magnetization and superparamagnetism.

Calcitriol enhances the effect of photodynamic therapy in human breast cancer.

PURPOSE: To investigate the killing effect of photodynamic therapy (PDT) mediated by hematoporphyrin derivative (HPD) on human breast cancer MCF7 and MDA-MB-231 cells in vitro. METHODS: MCF7 and MDA-MB-231 breast cancer cells cultured in vitro were incubated with calcitriol (concentration of 10-8M, 10-10 M, 10-12 M, 10-14 M, 10-16 M, 0 M) to determine a proper concentration. The cells were divided into experimental group (calcitriol, HPD group and laser), HPD group (HPD and laser), calcitriol group (calcitriol and laser), blank laser group (laser alone) and blank group (no drugs and laser). Then the cells were preconditioned with calcitriol for 48 hrs and incubated with HPD for 6 hrs. After light exposure with 630 nm laser, the cells' viability and the reactive oxygen species (ROS) were assessed. After 8 hrs, flow cytometry was applied to detect the rate of cell apoptosis. The fluorescence intensity in cells was detected. Furthermore, the expression of porphyrin synthetic enzymes in pretreated breast cancer cells was analyzed. RESULTS: MTT assay showed that the viability of cells in the experimental group was lowest (p<0.05). The ROS intensity of the experimental group was higher (p<0.01). The rate of cell apoptosis was higher in the experimental group (p<0.05), and the fluorescence of the experimental group was higher (p<0.01). Furthermore, mechanistic studies documented that the expression of the porphyrin synthesis enzyme coproporphyrinogen oxidase (CPOX) was increased by calcitriol at the mRNA level. CONCLUSION: This research revealed a simple, non-toxic and highly effective preconditioning regimen to selectively enhance protoporphyrin IX (PpIX) fluorescence and the response of HPD-PDT in breast cancer search. This finding suggests that the combined treatment of breast cancer cells with calcitriol plus HPD may provide an effective and selective therapeutic modality to enhance HPD-induced PpIX fluorescent quality for improving discrimination of tumor tissue and PDT efficacy.

Undifferentiated Neuroblastoma Cells Are More Sensitive to Photogenerated Oxidative Stress Than Differentiated Cells.

Neuroblastoma is one of the most aggressive cancers and has a complex form of differentiation. We hypothesized that advanced cellular differentiation may alter the susceptibility of neuroblastoma to photodynamic treatment (PDT) and confer selective survival advantage. We demonstrated that hematoporphyrin uptake by undifferentiated SH-SY5Y cells was lower than that of differentiated counterparts, yet the former were more susceptible to PDT-induced oxidative stress killing. Photogenerated reactive oxygen species (ROS) in undifferentiated cells efficiently stimulated cell cycle arrest at G2/M phase, mitochondrial apoptotic pathway activation, the sustained phosphorylation of Akt/GSK-3ß and ERK. Differentiated cells with more resistance to PDT exhibited a ROS-independent and a prolonged activation of ERK. Both SH-SY5Y cells exposed to PDT exhibited ROS-independent p38 and JNK activation. These results may have important implications for neuroblastoma patients undergoing photodynamic therapy.

Photodynamic Therapy-Induced Apoptosis of Keloid Fibroblasts is Mediated by Radical Oxygen Species In Vitro.

BACKGROUND: It has been demonstrated that photodynamic therapy (PDT) is a promising treatment approach for hyperplastic dermatosis and results in a beneficial outcome. In the present study, PDT involving hematoporphyrin monomethyl ether (HMME) was applied to keloid fibroblasts (KFB), and the effects and the mechanism of action were explored. METHODS: Keloid fibroblastic cells were divided into four groups (PDT group, light alone group, HMME alone group, normal cultured group). Cell proliferation and apoptosis were observed. Radical oxygen species (ROS) were detected by means of dihydroethidium (DHE) and dihydrorhodamine (DHR123). ROS in the PDT group were also assessed after addition of tiron. RESULTS: Cell proliferation was inhibited in the PDT group (p < 0.05), while the rate of apoptosis was also clearly increased (p < 0.05). The levels of ROS were significantly higher in the PDT group than was observed in the other three groups (p < 0.05). With the addition of tiron the damaging effects were reduced. CONCLUSIONS: Our data indicated that HMME-mediated PDT could inhibit keloid fibroblast proliferation and could also induce apoptosis. This process was associated with the production of ROS.