Hematoporphyrin Monomethyl Ether Concentration Research Articles

Microbubbles Ultrasonic Cavitation Regulates Tumor Interstitial Fluid Pressure and Enhances Sonodynamic Therapy

Sonodynamic therapy (SDT) is a promising treatment method for solid tumors. However, the high interstitial fluid pressure (IFP) in tumor tissues limits the accumulation of sonosensitizers. In the present study, microbubbles ultrasonic cavitation was used to regulate the tumor’s IFP and evaluate SDT effects. Rabbit VX2 tumor tissues were treated with microbubbles ultrasonic cavitation. The IFP of different tumor parts before and after cavitation was measured by the WIN method. The accumulation of the sonosensitizers hematoporphyrin monomethyl ether (HMME) in tumor tissues was observed using an ultramicro spectrophotometer and laser confocal microscope. Then, tumor-bearing rabbits were treated with SDT once a week for eight weeks and the therapeutic effect was evaluated. After microbubbles ultrasonic cavitation treatment, the tumor’s IFP decreased and the HMME concentration increased. We concluded that microbubbles ultrasonic cavitation can increase HMME accumulation in rabbit VX2 tumors and increase SDT therapeutic effects.

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 sonodynamic therapy induces A-253 cell apoptosis.

It has been found that >90% of oral cancer patients suffer from squamous cell carcinoma (SCC). The 5-year survival rate of SCC is ~50%, despite the availability of different treatments. Sonodynamic therapy (SDT) has been developed as a novel therapy for cancer, resisting bacterial infection and inhibiting atherosclerotic plaque progression. The present study investigated the efficacy of hematoporphyrin monomethyl ether (HMME)-mediated SDT on the A-253 epidermoid cancer cell line. The cytotoxicity of HMME and the survival rate of cells following SDT were examined by the MTT assay. Apoptosis and necrosis of cells were detected using flow cytometry with Annexin V and propidium iodide (PI) staining, and fluorescence microscopy with Hoechst 33258 and PI staining. Intracellular reactive oxygen species (ROS) and Ca2+ levels were measured using a fluorescence microscope based on 2′,7′-dichlorofluorescein diacetate and fluo-3/acetoxymethylester, respectively. Results of the MTT assay demonstrated that a lower concentration (<10 µg/ml) of HMME had no significant effect on the A-253 cells, but SDT combined with ultrasonic treatment for 1 min and 10 µg/ml HMME decreased the cell survival rate by 27%. Flow cytometry analysis revealed that A-253 cells in the SDT group had a higher rate of late apoptosis compared with the control group. Furthermore, fluorescence quantitation of apoptotic A-253 cells demonstrated that the percentages of apoptotic cells were increased in the ultrasound and SDT group compared with those in the control group. In the present study, the ROS level in the SDT group was elevated compared with that in the control group. The Ca2+ levels were increased to 181.2 and 268.7% in the ultrasound and SDT groups, respectively, relative to the control group. Taken together, the findings of the present study demonstrated that HMME-SDT significantly induces the apoptosis of A-253 cells together with intracellular ROS generation and Ca2+ overload. Thus, HMME-SDT may be a promising treatment option for patients with SCC.

Lymphatic targeting of hematoporphyrin monomethyl ether using poly (butyl-cyanoacrylate) based nanoparticle drug delivery system

The traditional treatment has inevitable drawbacks of nonspecific lymph targeting, poor therapeutic efficiency and residual metastatic for advanced cancer patients with lymph node metastases. To overcome these shortcomings, we prepare a nano-carrier drug delivery system. Photosensitizer hematoporphyrin monomethyl ether (HMME)-loaded poly (n-butylcyanoacrylate) nanoparticles (PBCA-NPs) was prepared successfully. The particle size was approximately 160 nm, the envelopment rate was 87.9%, and the drug loading rate was about 13.4%. The drug release study in vitro showed that the cumulative release rates of HMME-PBCA-NPs group was much less than free HMME group. The drug distribution in different tissues showed that the peak-reach time was 3 h in free HMME group and 6 h in nanoparticles group. All of these results confirmed the slow release characteristic of nanoparticles. In lymph node tissues, the HMME concentrations in HMME-PBCA-NPs group were much higher than those of the free HMME group at any time points we tested, in which the maximum difference concentration of HMME appeared at 6 h (1.2884 ± 0.04695 vs. 0.0438 ± 0.00558 µg/mg) after drug delivery. The mesenteric lymph nodes of rabbits were enlarged obviously in the NP group than in free HMME group at 6 h after drug delivery. All of these results confirmed the slow release characteristic and the lymphatic targeting characteristic of nanoparticles. In summary, we developed a lymphatic targeting nanoparticles drug delivery system successfully, which showed perfect lymph targeting and has the potential to be a new therapy strategy for advanced cancer patients with lymph node metastasis.

Visualization of Porphyrin-Based Photosensitizer Distribution from Fluorescence Images In Vivo Using an Optimized RGB Camera

A handheld RGB camera was developed to monitor the in vivo distribution of porphyrin-based photosensitizer (PS) hematoporphyrin monomethyl ether (HMME) in blood vessels during photodynamic therapy (PDT). The focal length, f-number, International Standardization Organization (ISO) sensitivity, and shutter speed of the camera were optimized for the solution sample with various HMME concentrations. After the parameter optimization, it was found that the red intensity value of the fluorescence image was linearly related to the fluorescence intensity under investigated conditions. The RGB camera was then used to monitor the in vivo distribution of HMME in blood vessels in a skin-fold window chamber model. The red intensity value of the recorded RGB fluorescence image was found to be linearly correlated to HMME concentrations in the range 0–24 μM. Significant differences in the red to green intensity ratios were observed between the blood vessels and the surrounding tissue.

Preparation and in vitro and in vivo release of ALA and HMME hydrogel suppository

Objective To prepare 5-aminolevulinic acid (ALA) and hematoporphyrin monomethyl ether (HMME) hydrogel suppositories and to evaluate their photosensitizer transfer efficiencies in rectal tumor tissue. Methods The BALB/c mice implanted SW837 rectal cancer cells subcutaneously were randomly divided into four groups: intrarectal suppository administration group, cutaneous administration group, intratumoral injection group and intravenous injection group. Fluorescence spectrophotometry was used to measure the concentration of protoporphyrin Ⅸ (PpⅨ) and HMME in rectal wall, skin and tumor tissue. The distribution of photosensitizer was determined by a fluorescence spectroscopy system. Results The concentration of PpⅨ in the ALA suppository administration group was 9.76 times (1 h) and 5.80 times (3 h) higher than that in the cutaneous administration group, and the differences were statistically significant (all P<0.05). The maximal penetration depth of ALA in tumor tissue was about 3-6 mm at 2 h after the cutaneous administration. After the HMME suppository administration, the concentration of HMME in the rectal wall was very low. The maximal penetration depth of HMME in tumor tissue was less than 2 mm after the cutaneous administration. Conclusions ALA is more likely to penetrate mucosal barrier compared to skin tissue. The hydrogel suppository based rectal administration is expected to be a new administration method for the rectal cancer photodynamic therapy using ALA. Key words: Photosensitizer; Drug delivery; Photodynamic therapy; HMME; ALA; Rectal cancer

HMME combined with green light-emitting diode irradiation results in efficient apoptosis on human tongue squamous cell carcinoma.

Hematoporphyrin monomethyl ether (HMME) is a novel and promising porphyrin-related photosensitizer for photodynamic therapy (PDT). This study aimed to investigate the efficacy and potential mechanism of HMME-PDT under irradiation of green light-emitting diode (LED) with wavelength of 530 ± 20nm in treating human tongue squamous cell carcinoma Tca8113 cells in vitro. The HMME concentrations were 1.25, 2.5, and 5μg/ml while the energy densities were 0.6, 1.2, 1.8, 2.4, and 3.0J/cm(2). MTT assay demonstrated that HMME-PDT significantly inhibited the proliferation of Tca8113 cells, and the cytotoxicity was improved with increased HMME concentration and light intensity. The amount of cells decreased significantly and the morphology of cells changed drastically after HMME-PDT. Flow cytometry analysis revealed that HMME-PDT induced both apoptosis and necrosis, but apoptosis was the main form of cell death. Apoptotic morphology was confirmed by Hoechst 33342 staining. Laser scanning confocal microscopy observation showed that HMME was mainly localized in mitochondria. The production of intracellular reactive oxygen species increased remarkably after PDT treatment, and both sodium azide (the singlet oxygen quencher) and D-mannitol (the hydroxyl radical scavenger) could protect Tca8113 cells from death induced by HMME-PDT. Additionally, the activity of caspase-3 also increased markedly in treated groups, and the cell death could be rescued by a reversible inhibitor (Ac-DEVD-CHO) of caspase-3. These results demonstrated that HMME combined with green LED significantly induced apoptosis of Tca8113 cells, suggesting that HMME-PDT using green LED might be a potential therapeutic strategy for human tongue squamous cell carcinoma.

Potential role of organic anion transporting polypeptide 1B1 (OATP1B1) in the selective hepatic uptake of hematoporphyrin monomethyl ether isomers.

Hematoporphyrin monomethyl ether (HMME), which consists of equal amounts of isomers HMME-1 and HMME-2, is a novel porphyrin-related drug for photodynamic therapy. This study was aimed to investigate the uptake transporter-mediated selective uptake of HMME into the liver and to identify the major uptake transporter isoforms involved. Adult SD rats were intravenously injected with a single dose of HMME (5 mg/kg) with or without rifampicin (an inhibitor of organic anion transporting polypeptides OATP1B1 and OATP1B3, 25 mg/kg). Blood samples were collected, and HMME concentrations were measured using LC-MS/MS. Rat hepatocytes, human hepatocytes and HEK293 cells expressing OATP1B1, OATP1B3, or OATP2B1 were used to investigate the uptake of HMME or individual isomers in vitro. Co-administration of rifampicin significantly increased the exposure of HMME isomers, and decreased the AUC ratio of HMME-1 to HMME-2 from 1.98 to 1.56. The uptake of HMME-2 into human hepatocytes and the HEK293 cells expressing OATP1B1 or OATP2B1 in vitro was 2-7 times greater than that of HMME-1, whereas OATP1B3 mediated a higher HMME-1 uptake. OATP1B1 exhibited a higher affinity for HMME-2 than for HMME-1 (the Km values were 0.63 and 5.61 μmol/L, respectively), which were similar to those in human hepatocytes. By using telmisartan (a non-specific OATP inhibitor) and rifampicin, OATP2B1 was demonstrated to account for <20% of hepatic HMME uptake. OATP1B1 is the major transporter involved in the rapid hepatic uptake of HMME, and the greater uptake of HMME-2 by OATP1B1 may lead to a lower exposure of HMME-2 than HMME-1 in humans.

Sonodynamic effects of hematoporphyrin monomethyl ether on Staphylococcus aureus in vitro.

This study aims to investigate the effect of hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic antimicrobial chemotherapy (SACT) on Staphylococcus aureus. SACT was carried out using HMME and 1 MHz ultrasound irradiation. The bactericidal effect was evaluated by the counting colony-forming units (CFU), and important SACT parameters including ultrasound intensity and HMME concentration were determined. More than 95% of the bacteria colonies were effectively killed in the SACT group by 50 μg mL(-1) HMME combined with 6 W cm(-2) tone-burst ultrasound at 1 MHz, but this ultrasound level without HMME only reduced CFU by 38%. In the sonodynamic treatment, higher HMME concentrations and higher ultrasound intensities caused more death of bacteria. Incubation with different HMME concentrations without ultrasound showed no effect. Our results show that the HMME-mediated SACT can be significantly in killing S. aureus.

Growth inhibition effect of HMME-mediated PDT on hepatocellular carcinoma HepG2 cells.

Photodynamic therapy (PDT) is considered a promising new strategy for liver cancer treatment. Three elements of PDT--optical output power, irradiation time, and photosensitizer concentration--play important roles in promoting cell death. This research aimed to characterize the effects of hematoporphyrin monomethyl ether (HMME)-based PDT on hepatocellular carcinoma cells HepG2 and thus elucidate the relationship between cell death and the three elements mentioned earlier. Furthermore, in this study, we present a parameter that represents the cumulative effects of these elements. The accumulation of HMME in HepG2 cells was observed by fluorescence microscopy. The absorption spectrum of HMME was detected using fluorescence spectral analysis. The viability of the treated cells was determined using the MTT assay, and cell apoptosis was evaluated using flow cytometry. We found that the fluorescence intensity was positively correlated with the incubation time for up to 2 h. The cell growth inhibition rate was significantly high and gradually increased with increasing concentrations of HMME or increasing light intensity, which was calculated as optical output power × irradiation time. Further analysis revealed an e-exponential decay of the cell survival rate to the product of the HMME concentration and the light intensity. We defined the product as parameter B (B = optical output power × irradiation time × HMME concentration). Similarly, the rate of cell apoptosis showed roughly e-exponential growth to parameter B. In conclusion, HMME-mediated PDT can significantly kill HepG2 cells, and the killing effect was related to the cumulative effects of the optical output power, the irradiation time, and the HMME concentration. Therefore, the newly defined parameter B, as a comprehensive physical quantity, may be of great significance for the regulation of light and photosensitizer according to patient-specific conditions in clinical practice.

Bactericidal effects of hematoporphyrin monomethyl ether-mediated photosensitization against pathogenic communities from supragingival plaque

Photodynamic antimicrobial chemotherapy (PACT) is proposed as a potential candidate to inactivate pathogens in localized infections due to the rapid evolution of bacterial resistance. The treatment modality utilizes nontoxic agents called photosensitizers and harmless visible light to generate reactive oxygen species which result in microbial cells' killing. Hematoporphyrin monomethyl ether (HMME) as a novel and affordable photosensitizer has been used in treating various clinical diseases for years, but few applications in infection. In this report, we studied the bactericidal effects of the HMME-mediated photodynamic reaction on the pathogenic microbes in supragingival plaque which can lead to many oral infectious diseases such as caries, gingivitis, and so on. Our findings demonstrated that HMME promoted an effective action in bacterial reduction with the application of laser energy. Moreover, the antimicrobial activities were dramatically enhanced as the HMME concentration and exposure time were increased, but reached a plateau when matched the appropriate agent concentration and illumination. It was found that the survival fraction of microorganisms is exponentially dependent on the product of HMME concentration and irradiation time. These promising results suggest the HMME may be an excellently cost-effective photosensitizing agent for mediating PACT in the treatment of supragingival plaque-related diseases. An optimized HMME concentration and irradiation time has been found to achieve the best results under our experimental conditions. The high HMME concentration matching short curative time, or vice versa, can achieve the similar therapeutic effect, which may provide more flexible treatment plans according to specific conditions.

Apoptosis of U937 Cells Induced by Hematoporphyrin Monomethyl Ether-Mediated Sonodynamic Action

The present study aims to investigate apoptosis of U937 cells induced by hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic therapy (SDT). HMME concentration was kept constant at 10 μg/mL. Tumor cells suspended in serum-free RPM1640 were exposed to ultrasound at 1.1 MHz for up to 60 seconds with an intensity of 1 W/cm(2) in the presence and absence of HMME. The viability of cells was determined by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide tetrazolium (MTT) test. Apoptosis was analyzed using a flow cytometer with Annexin V-PE/7-ADD staining as well as fluorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. The DNA damage of U937 cells, intracellular reactive oxygen species (ROS), and mitochondria membrane potential (MMP) were also analyzed by a flow cytometer after exposures. Western blotting and reverse transcriptase-polymerase chain reaction were used to analyze the protein and mRNA expression level of caspase-3 and poly(ADP-ribose) polymerase (PARP). Fluorescent imaging revealed that HMME mainly localized in the mitochondria. MTT assay showed 55.6% of cell survival at 4 hours post-SDT. Flow cytometric analysis displayed a significant increase in the early- and late-apoptotic cell populations (35.6%) of U937 cells by HMME-mediated SDT. Compared with the control, ultrasound-alone, and HMME-alone groups, the intracellular ROS and the MMP loss were greatly increased in the combined SDT group. Obvious nuclear condensation was also found with DAPI staining, and the DNA fragment increased to 33.9% at 2 hours post-SDT treatment. Immunofluorescent staining indicated obvious Bax translocation after SDT. Western blot showed visible enhancement of caspase-3 and PARP cleavage. In addition, caspase-3 and PARP mRNA expression of U937 cells increased remarkably after SDT treatment. The findings demonstrated that HMME-mediated sonodynamic action (HMME-SDT) significantly induced apoptosis of U937 cells, suggesting that HMME may be a good sonosensitizer, and HMME-SDT might be a potential therapeutic strategy for cancer treatment.

HEMATOPORPHYRIN MONOMETHYL ETHER-MEDIATED PHOTODYNAMIC EFFECTS ON MACROPHAGES

ObjectivesPhotodynamic therapy (PDT) has been shown to attenuate atherosclerotic plaque progression and decrease macrophage-infiltration. The effectiveness of PDT depends strongly on the type of photosensitizers. Hematoporphyrin monomethyl ether (HMME) is...

Photoinactivation of cell-free human immunodeficiency virus by hematoporphyrin monomethyl ether

Human immunodeficiency virus (HIV) particles that remain in the blood of patients are frequently ignored as targets for AIDS treatment. We therefore investigated the use of photodynamic therapy (PDT) with hematoporphyrin monomethyl ether (HMME) as a means of inactivating cell-free HIV in vitro. Virus particles including HIV-1IIIB, resistant HIV-1 variants, HIV-1 clinical variants, and HIV-2 variants were incubated with HMME for 40 min, followed by irradiation with a 630-nm semiconductor laser at an energy density of 0.3 J/cm2. The antiviral effects were evaluated by counting syncytium formation or measuring p24 antigen expression levels in supernatants by enzyme-linked immunosorbent assay. The relationships between photoinactivation and HMME concentrations, energy density, power density and antioxidants (NaN3 and d-mannitol) were also assessed using the above methods. All the tested virus particles were completely responsive to HMME-PDT. HMME concentration and energy density were positively correlated with photoinactivation of HIV, while power density was negatively correlated. Both sodium azide and d-mannitol weakened the inhibitory effect of PDT on virus-induced membrane fusion, with d-mannitol having a stronger effect. HMME-PDT can inactivate HIV particles, and may therefore represent a promising treatment for AIDS patients.

Sonodynamic effects of hematoporphyrin monomethyl ether on CNE‐2 cells detected by atomic force microscopy

Hematoporphyrin monomethyl ether (HMME) has been effectively used to treat solid tumors of some types. However, its application in nasopharyngeal carcinoma has not been studied yet. In this paper, the detailed sonodynamic effects of HMME-SDT (sonodynamic therapy) on CNE-2 cells including cell growth inhibition, apoptosis induction, and membrane toxicity were investigated. It was found that HMME alone had less cytotoxicity whereas HMME-SDT could suppress the cell proliferation in a dose-dependent manner as detected by MTT assay. The annexin V-based flow cytometric data indicated that upon SDT, different concentrations of HMME induce distinct types of cell death, apoptosis by low concentration (60 µg/ml) of HMME and necrosis by higher concentration (120 µg/ml). The immunofluorescence of cytoskeleton and nuclei morphology showed that upon HMME-SDT, the cells became rounding and the cytoskeletal network disappeared, and, the nuclei represented a total fragmented morphology of nuclear bodies. These alternations showed the apoptosis induction by HMME-SDT. Further AFM study showed that the cell membrane structure and cytoskeleton networks were destroyed, and, the Young's modulus, tip-cell-surface adhesion force decreased to 0.22 ± 0.11 Mpa, 35.4 ± 12.8 pN of cells with 120 µg/ml HMME-SDT from 0.48 ± 0.21 Mpa, 69.6 ± 22.3 pN of native cells, respectively. These membrane changes caused the collapse of mitochondrial transmembrane potential and disturbance of intracellular calcium homeostasis, which was consistent with the results detected by flow cytometry. Therefore, membrane toxicity and cytoskeleton disrupture induced by HMME-SDT maybe important factors to induce cell apoptosis, and, the disturbance of mitochondrial transmembrane potential and calcium channels might be the apoptosis mechanisms.

Hematoporphyrin Monomethyl Ether Enhances the Killing of Ultrasound on Osteosarcoma Cells Involving Intracellular Reactive Oxygen Species and Calcium Ion Elevation

The present study aims to investigate the possible mechanisms of hematoporphyrin monomethyl ether (HMME) enhancing the cytotoxicity of ultrasound in osteosarcoma cells. Osteosarcoma cell line UMR-106 was treated by HMME and ultrasound radiation, with the HMME concentration kept at 20 μg/mL and ultrasound radiation for 10 seconds at the intensity of 0.5 W/cm². Cell proliferation was investigated at 12, 24, 36, and 48 hours using MTT assay after ultrasound and HMME treatment. Ultrastructural morphology was observed using transmission electron microscopy (TEM). Intracellular reactive oxygen species (ROS) was measured using a flow cytometry with DCFH-DA staining and intracellular free calcium ion (Ca(2+)) with Fluo-3-AM staining. The UMR-106 cells proliferated rapidly in the sham radiation and HMME treatment alone group, but ultrasound-treated cells and HMME-ultrasound-treated cells proliferated slowly. There was a significant difference between HMME-ultrasound treatment and the controls, including ultrasound radiation, HMME treatment alone, and sham radiation (P < .05). TEM showed endoplasmic reticulum and mitochondrial swelling in the ultrasound-treated cells, and more cells presented apoptosis and necrosis after treatment with ultrasound and HMME together. Intracellular ROS and Ca(2+) in the cells increased more significantly after both ultrasound and HMME treatment than after ultrasound treatment alone. HMME could effectively enhance the inhibition effect of ultrasound on osteosarcoma cells. Intracellular ROS and Ca(2+) in the UMR-106 cells increased more significantly after the treatment of HMME and ultrasound together, indicating that the enhancement of HMME on ultrasound cytotoxicity to osteosarcoma cells possibly involves both intracellular ROS and Ca(2+) elevation.

Hematoporphyrin monomethyl ether-mediated photodynamic effects on THP-1 cell-derived macrophages

Photodynamic therapy (PDT) has been shown to attenuate atherosclerotic plaque progression and decrease macrophage-infiltration. The effectiveness of PDT depends strongly on the type of photosensitizers. Hematoporphyrin monomethyl ether (HMME) is a promising second-generation porphyrin-related photosensitizer for PDT. This study is designed to characterize effects of HMME-based PDT on THP-1 cell-derived macrophages and define the cell-death pathway. HMME was identified to accumulate in the macrophages by fluorescence microscopy and confocal scanning laser microscope. Our data demonstrated that the intensity of laser-induced HMME fluorescence in macrophages steadily increased with the increasing incubation concentration of HMME. The survival rate of macrophages determined by MTT assay decreased with the increasing HMME concentration and irradiation time. HMME-based PDT induced macrophage apoptosis via caspase-9 and caspase-3 activation pathway detected by caspase fluorescent assay kit and flow cytometer. The PDT increased the number of apoptotic macrophages by 14-fold at 12 h post irradiation by 9 J/cm 2 635 nm diode laser. These results imply that photodynamic therapy with HMME may therefore be a useful clinical treatment for unstable atherosclerotic plaques.

Study on the interaction between hematoporphyrin monomethyl ether and DNA and the determination of hematoporphyrin monomethyl ether using the resonance light scattering technique

The interaction between photosensitizer anticancer drug hematoporphyrin monomethyl ether (HMME) and ctDNA has been studied based on the decreased resonance light scattering (RLS) phenomenon. The RLS, UV–vis and fluorescence spectra characteristics of the HMME–ctDNA system were investigated. Besides, the phosphodiesters quaternary ammonium salt (PQAS), a kind of new gemini surfactant synthesized recently, was used to determine anticancer drug HMME based on the increasing RLS intensity. Under the optimum assay conditions, the enhanced RLS intensity was proportional to the concentration of HMME. The linear range was 0.8–8.4 μg mL −1, with correlation coefficient R 2 = 0.9913. The detection limit was 0.014 μg mL −1. The human serum samples and urine samples were determined satisfactorily, which proved that this method was reliable and applicable in the determination of HMME in body fluid. The presented method was simple, sensitive and straightforward and could be a significant method in clinical analysis.

Differences in sensitivity to HMME-mediated photodynamic therapy between EBV+ C666-1 and EBV− CNE2 cells

The aim of this study was to compare the sensitivity of hematoporphyrin monomethyl ether (HMME)-mediated PDT in the Epstein-Barr virus (EBV) positive and negative human nasopharyngeal carcinoma (NPC) cells. The intracellular uptake of HMME in C666-1 (EBV+) and CNE2 (EBV-) cells was quantitatively determined after incubating with different concentration of HMME. The subcellular localization of HMME was examined under a laser scanning fluorescence microscopy. The survival rate of C666-1 and CNE2 cells after HMME PDT was evaluated with clonogenic assay. The EBV- CNE2 cells showed higher intracellular uptake of HMME and lower survival rate than EBV+ C666-1 cells. There was no significant difference in terms of subcellular localization of HMME between C666-1 and CNE2 cells. The sensitivity of EBV- CNE2 cells to HMME-mediated PDT was significantly higher than that of EBV+ C666-1 cells. The intracellular uptake of HMME plays a key role in determining the PDT sensitivity.