Hematoporphyrin Derivative Research Articles

Efficacy of porphyrin derivative, Chlorhexidine and PDT in the surface disinfection and roughness of Cobalt chromium alloy removable partial dentures

AimThe present study aimed to evaluate the effect of different cleansers and photodynamic therapy (PDT) on disinfection of Co/Cr removable partial denture colonized with C. albicans, S.aureus and S.mutans. Material and MethodsTwenty-five Co/Cr removable partial dentures were constructed. and inoculated by American Type Culture Collection (ATCC) of Candida albicans, S.aureus, and S.mutans in an in-vitro setup. Co/Cr removable partial dentures were randomly allocated into five groups and framework was immersed in 15 mL of contaminated culture medium broth. Based on the cleansing method, disinfected dentures in group 1 were cleansed with porphyrin derivative; group 2 was exposed to 0.12% chlorhexidine digluconate; samples in group 3 and group 4 were subjected to sodium perborate enzyme and citric acid respectively. Through a surface analyzer, the surface roughness of Co/Cr and methacrylate resin was measured in 3 different zones in micrometers before and after disinfection. Two-way ANOVA and Tukey's test was used to analyze the data. Levene test was used to assess the normal distribution of data. Significance level p< 0.05 ResultsThe results of metal roughness displayed that Co/Cr used as an alloy did not exhibit significant difference when exposed to different chemical disinfectants and photosensitizer (p > 0.05). Similarly, surface roughness (Ra) of heat polymerized acrylic resin using cleansers and PDT demonstrated no significant difference. Intergroup comparison showed that, hematoporphyrin derivative displayed comparable cleansing property against S. aureus, C.albicans, and S. mutans compared to to 0.12% CHX digluconate (p>0.05). The intragroup comparison showed hematoporphyrin derivative and CHX were equally effective against all bacteria (p>0.05). ConclusionCHX digluconate and hematoporphyrin derivative demonstrated high antimicrobial activity against S.aureus, S.mutans, and C.albicans with minimum Ra of an acrylic denture and Co/Cr metallic framework.

Photodynamic Therapy-Current Limitations and Novel Approaches.

Photodynamic therapy (PDT) mostly relies on the generation of singlet oxygen, via the excitation of a photosensitizer, so that target tumor cells can be destroyed. PDT can be applied in the settings of several malignant diseases. In fact, the earliest preclinical applications date back to 1900’s. Dougherty reported the treatment of skin tumors by PDT in 1978. Several further studies around 1980 demonstrated the effectiveness of PDT. Thus, the technique has attracted the attention of numerous researchers since then. Hematoporphyrin derivative received the FDA approval as a clinical application of PDT in 1995. We have indeed witnessed a considerable progress in the field over the last century. Given the fact that PDT has a favorable adverse event profile and can enhance anti-tumor immune responses as well as demonstrating minimally invasive characteristics, it is disappointing that PDT is not broadly utilized in the clinical setting for the treatment of malignant and/or non-malignant diseases. Several issues still hinder the development of PDT, such as those related with light, tissue oxygenation and inherent properties of the photosensitizers. Various photosensitizers have been designed/synthesized in order to overcome the limitations. In this Review, we provide a general overview of the mechanisms of action in terms of PDT in cancer, including the effects on immune system and vasculature as well as mechanisms related with tumor cell destruction. We will also briefly mention the application of PDT for non-malignant diseases. The current limitations of PDT utilization in cancer will be reviewed, since identifying problems associated with design/synthesis of photosensitizers as well as application of light and tissue oxygenation might pave the way for more effective PDT approaches. Furthermore, novel promising approaches to improve outcome in PDT such as selectivity, bioengineering, subcellular/organelle targeting, etc. will also be discussed in detail, since the potential of pioneering and exceptional approaches that aim to overcome the limitations and reveal the full potential of PDT in terms of clinical translation are undoubtedly exciting. A better understanding of novel concepts in the field (e.g. enhanced, two-stage, fractional PDT) will most likely prove to be very useful for pursuing and improving effective PDT strategies.

630 nm激光对血卟啉衍生物介导的裸鼠肺腺癌A549移植瘤杀伤效应实验研究

630 nm激光对血卟啉衍生物介导的裸鼠肺腺癌A549移植瘤杀伤效应实验研究

Laser photodynamic therapy in the treatment of cervical pathology

Early diagnosis and treatment of background and precancerous diseases of the cervix is one of the important problems of gynecology, the ultimate goal of which is to reduce the incidence of cervical cancer. To date, many scientific papers have been devoted to the problem of treating cervical pathology and various methods of treating background and precancerous diseases of the cervix have been introduced. The most common methods are those based on the use of electro coagulation, cry destruction, and laser vaporization methods as a therapeutic effect. According to domestic and foreign authors, the therapeutic effect of the above-mentioned methods of treatment is 67-98. 7% [1, 2, 5]. However, each of these methods has its own indications, contraindications and a number of complications: exacerbation of chronic salpingoophoritis, bleeding, the occurrence of endometriosis, scarring of the cervix, cervical canal stenosis, violation of reproductive function [2, 4, 6, and 9]. In order to prevent cervical cancer, the treatment of background and precancerous diseases should be radical, but at the same time careful, while preserving the anatomical and functional fullness of the cervix, which largely determines the state of the reproductive system. In this regard, treatment methods are currently being developed that combine the optimal therapeutic effect in the absence of undesirable complications. One of the newest approaches to the treatment of cervical pathology is laser photodynamic therapy (LFTT). This method causes selective death of pathological cells, which is provided by the selectivity of the accumulation of the drug in the pathological tissue and local light supply. According to foreign sources, there are isolated cases of successful treatment of dysplasia and cervical cancer with the use of hematoporphyrin derivatives as a photosensitizer. In the sources available to us, no information was found about the use of LFTD in the treatment of background and precancerous diseases of the cervix, and the effectiveness of the drug “0.05% solution of mytilene blue belonging to the group of phenothiazines (cationic azines)” in the use of LFTD in gynecology was not evaluated, which determined the purpose of our study.

Photodynamic Anti-Tumor Efficiency of Hematoporphyrin Derivative

Photodynamic therapy (PDT) is an emerging non-invasive treatment based on a combination of photochemistry and photophysics. PDT has more advantages compared with traditional...

The study of effect and mechanism of 630-nm laser on human lung adenocarcinoma cell xenograft model in nude mice mediated by hematoporphyrin derivatives.

To investigate the effect and mechanism of 630-nm laser on human lung adenocarcinoma cell xenograft model in nude mice mediated by hematoporphyrin derivatives (HPD) and provide theoretical basis for clinical photodynamic therapy (PDT). Human lung adenocarcinoma cell xenograft model in nude mice was established and randomly divided into four groups: control group, pure photosensitizer group, pure irradiation group, and photodynamic treatment group. The tumor volume growth was compared, and the tumor growth inhibition rate was calculated. HE staining was used for routine pathological observation of tumor sections, and gross conditions of cells, interstitium, and blood vessels in several groups of tumor tissues were observed. TUNEL staining was used to observe and compare the apoptosis induced by photodynamic therapy. Real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression level of angiogenesis-related factors VEGF, HIF-1α and apoptosis-related factors Bax and Bcl-2 mRNA in the transplanted tumor tissues. Western blot was employed to detect the expression of angiogenesis-related proteins VEGF, HIF-1α and apoptosis-related proteins Bax, Caspase-3, and Bcl-2. Compared with the other three groups, the tumor growth inhibition rate of the photodynamic treatment group was significantly increased and the difference was statistically significant (P < 0.05). HE staining showed that the animal model of lung adenocarcinoma A549 was successfully established. TUNEL staining revealed that more apoptotic cells were found in the photodynamic treatment group, and the apoptosis index was calculated. Compared with the other three groups, the difference was statistically significant (P < 0.05). RT-PCR results showed that compared with the other three groups, the mRNA expressions of VEGF, HIF-1α, and Bcl-2 in the photodynamic treatment group decreased, while the expression of Bax mRNA increased(P < 0.05), and the differences were statistically significant. Western blot results showed that protein expressions of VEGF, HIF-1α, and Bcl-2 decreased in the photodynamic treatment group, while protein expression level of Bax and Caspase-3 increased (P < 0.05), indicating statistically significant differences. The 630-nm laser mediated by hematoporphyrin derivatives can significantly inhibit the growth of human lung adenocarcinoma xenograft tumor in nude mice, the mechanism of which is related to the inhibition of tumor angiogenesis by down-regulating VEGF and HIF-1α gene expression, and the promotion of tumor apoptosis by up-regulating Bax, Caspase-3, and down-regulating Bcl-2 gene expression.

The study of killing effect and inducing apoptosis of 630-nm laser on lung adenocarcinoma A549 cells mediated by hematoporphyrin derivatives in vitro.

To investigate the killing effect and inducing apoptosis of 630-nm laser mediated by hematoporphyrin derivatives (HPD) on human lung adenocarcinoma A549 cells. The human lung adenocarcinoma A549 cells were incubated at random with different concentrations of HPD (5, 10, 12, 15, 20μg/ml) for 4h and then illuminated by 630-nm laser with different energy densities (25, 50, 75, 100mW/cm2). And, meanwhile, the simple photosensitizer group, laser irradiation group, and blank control group were established. Then, CCK8, Hoechst 33258 staining, RT-PCR, and Western blot were employed. HPD-PDT proved no killing effect on the lung adenocarcinoma A549 cells with photosensitizer or laser irradiation alone. With the combination, the killing effect was obvious. CCK8 showed that the A549 cell viability in 15μg/ml and 20μg/ml HPD group as well as 50mW/cm2, 75mW/cm2, and 100mW/cm2 power density group decreased significantly compared with the control group. Hoechst 33258 staining showed that with the increase of HPD concentration, the cells presented chromatin fixation and hyperchromatic nuclei. The Annexin V-FITC/PI double staining was used to detect the apoptosis rate, and the difference was statistically significant. RT-PCR and Western blot showed that the expression of Caspase-3 and Bax were significantly up-regulated. However, the Bcl-2 and Survivin were significantly down-regulated in the HPD-PDT group, while those of the other three groups showed no significant changes. HPD-PDT has a significant effect on A549 cells. The mechanism of action may be related to the upregulation of the expression of Caspase-3, Bax, and downregulation of the expression of Bcl-2 and Survivin.

Identification of the targets of hematoporphyrin derivative in lung adenocarcinoma using integrated network analysis

BackgroundHematoporphyrin derivative (HPD) has a sensibilization effect in lung adenocarcinoma. This study was conducted to identify the target genes of HPD in lung adenocarcinoma.MethodsRNA sequencing was performed using the lung adenocarcinoma cell line A549 after no treatment or treatment with X-ray or X-ray + HPD. The differentially expressed genes (DEGs) were screened using Mfuzz package by noise-robust soft clustering analysis. Enrichment analysis was carried out using “BioCloud” online tool. Protein–protein interaction (PPI) network and module analyses were performed using Cytoscape software. Using WebGestalt tool and integrated transcription factor platform (ITFP), microRNA target and transcription factor (TF) target pairs were separately predicted. An integrated regulatory network was visualized with Cytoscape software.ResultsA total of 815 DEGs in the gene set G1 (continuously dysregulated genes along with changes in processing conditions [untreated—treated with X-ray—X-ray + treated with HPD]) and 464 DEGs in the gene set G2 (significantly dysregulated between X-ray + HPD-treated group and untreated/X-ray-treated group) were screened. The significant module identified from the PPI network for gene set G1 showed that ribosomal protein L3 (RPL3) gene could interact with heat shock protein 90 kDa alpha, class A member 1 (HSP90AA1). TFs AAA domain containing 2 (ATAD2) and protein inhibitor of activated STAT 1 (PIAS1) were separately predicted for the genes in gene set G1 and G2, respectively. In the integrated network for gene set G2, ubiquitin-specific peptidase 25 (USP25) was targeted by miR-200b, miR-200c, and miR-429.ConclusionRPL3, HSP90AA1, ATAD2, and PIAS1 as well as USP25, which is targeted by miR-200b, miR-200c, and miR-429, may be the potential targets of HPD in lung adenocarcinoma.

Progression of basic research, clinical application of photodynamic therapy and fluorescence-guided surgery in glioma treatment

The prognosis of glioma remains poor because of the infiltrative nature and the high local relapse rate. The current goals for patients with gliomas is maximal safe resection and adjuvant therapy. Tumor-specific photosensitizer, such as hematoporphyrin derivative (HpD) 5-aminolevulinic acid (5-ALA), can be selective up-taken and accumulated in tumor tissue. Light with appropriate wavelength can penetrate tumor tissue and excite the photosensitizer. The excited photosensitizer within glioma cells permits fluorescence visualization of tumor tissue during surgery and has been introduced in treatment of glioma as fluorescence-guided surgery (FGS). On the other hand, the toxicity of singlet oxygen generated by the excited photosensitizer has been used as photodynamic therapy (PDT) in selective destruction of the tumor. Some reports demonstrated the usefulness of adding PDT as an intraoperative adjuvant therapy, but the complexity associated with its implementation and the introduction of TMZ prevented PDT from becoming a routine therapy. However, FGS using 5-ALA in patients with malignant brain tumors has surfaced globally and may become a useful tool in increasing the extent of resection in gliomas.

Photoimmunotherapy by Cortactin monoclonal antibody conjugated with Hematoporphyrin derivative of a subcutaneous murine mammary adenocarcinoma using low power He-Ne laser

Photoimmunotherapy (PIT) is a promising approach which aims to increase the specificity of photosensitisers used in photodynamic therapy through its conjugation to monoclonal antibodies (MAb) directed against tumour antigens. The current study aims to increase and improve the therapeutic selectivity of photodynamic therapy (PDT) by conjugating the HpD to specific (mAb) in order to target one of the specific antigens of mammary adenocarcinoma. a screening has been done to detect specific antigens on mammary adenocarcinoma cells and we found that Cortactin is the unique antigen on tumor tissue in our model, then anti-cortactin mAb was linked to HPD, used for not only improve specificity, but vastly enhances tumor cell killing when they are photo-immunotargeted by HpD-monoclonal antibody conjugates comparing with unconjugated HPD and then exposed to low power He-Ne laser (632 nm). Female mice, which were transplanted with AM3 (mouse mammary adenocarcinoma transplantable tumor line), were randomly divided into five groups of 10 mice each; the first group was treated by PIT using HpD conjugated with Cortactin, in comparison with HpD alone in a second group. The third and fourth were control groups with and without HpD alone respectively. Tumor growth indices and metastasis incidence were calculated. Photoimmunotargeting by HpD-mAb conjugates activated by a low-power He-Ne laser showed significant tumor growth inhibition similar to PDT using unconjugated HpD activated by He-Ne laser, whilst control groups were without any significant effect. The resultssuggest that conjugation was with low quantity of the HPD or not stable enough and this need further studies.

Photodynamic Action of low power He-Ne laser on photosensitized human Hep-2 and AMN3 cell lines with Hematoporphyrin derivative in vitro

Photodynamic Action (PDA) by using appropriate wavelength of irradiation conjugated with porphyrin derivatives is a powerful mechanism of tumor destruction. Hematoporphyrin derivative has been shown to selectively localize in neoplastic cells and then cause destruction of them by generation of singlet oxygen when activated by low power He-Ne laser. Light which used in this study has been emitting from this laser has a wavelength equal to 632.8 nm (red light). Doses of laser had been varied from 3.6 J/cm2 to 14.4 J/cm2 . The beam of laser adjusted with a modified tissue culture plate. Cell lines had exposed to Hematoporphyrin D (HpD) for 24 hours before Laser exposure, their concentrations were varied from 5 µg/ml to 80 µg/ml. Results clearly proved a Photodynamic Action of laser conjugated with photosensitizer. No significant difference in cell viability was detected using neither the laser doses alone nor the photosensitizer (HpD) alone. Therefore, we believe that the low power He-Ne laser conjugated with hematoporphyrin derivatives’ as a photosensitizer will open the door wide for photodynamic therapy of tumors.

Cetuximab tagged and oleic acid modified chitosan nanoparticles for tumor targeted quercetin delivery

Hypericin (HY) is a photoactive aromatic dianthraquinone that is considered a potent photodynamic agent. In this study, hypericin and two other photosensitizers, a hematoporphyrin derivative (Photogem®; PG) and a chlorin derivative (Photodithazine®; PZ), were compared in terms of their phototoxicity toward two cell lines, HEp-2 and Vero. The median inhibitory concentration (IC50) of each of the photosensitizers was obtained after a 16.2 J cm−2 dose of irradiation at 630 ± 10 nm. The IC50 values were 0.07 ± 0.01 (HY), 1.0 ± 0.2 (PZ), and 9 ± 1 μg mL−1 (PG) in HEp-2 cells and 0.3 ± 0.1 (HY), 1.6 ± 0.2 (PZ) and 11 ± 1 μg mL−1 (PG) in Vero cells, showing that HY is more phototoxic than the others when irradiated at 630 nm. If these results are analyzed, simultaneously, with the first-order constant for BSA tryptophan photooxidation, obtained by fluorescence decay (λexcitation = 280 nm), which are 11 × 10−3 min−1 ± 1. 10−3 min−1 (HY), 10 × 10−3 min−1 ± 1 × 10−3 min−1 (PZ), and 6 × 10−3 min−1 ± 1 × 10−3 min−1 (PG), it is possible to infer that the photodynamic efficiency alone is not sufficient to explain the higher HY phototoxicity. The lipophilicity is also an important factor for an efficient target cell accumulation and was assessed for all sensitizers through the octanol–water partition coefficient (log P): 1.20 ± 0.02 (HY), −0.62 ± 0.03 (PZ), and −0.9 ± 0.2 (PG). The higher value for HY correlates well with its observed superior efficiency to promote damage at low concentrations and doses. As HY is used for the long-term treatment of mild depression, it is considered safe for humans. This fact and the present results reinforce the great potential of this photosensitizer to replace porphyrin derivatives, with the advantages that mean it could be used as photosensitizer in clinical photodynamic therapy.

Photodynamic treatment outcomes of potentially-malignant lesions and malignancies of the head and neck region: A systematic review.

The aim of the present study was to systematically review the efficacy of photodynamic therapy (PDT) in the management of oral potentially-malignant disorders (PMDS) and head and neck squamous cell carcinoma (HNSCC). From 1985 to 2015, PubMed/Medline, Google Scholar, EMBASE, and ISI Web of Knowledge were searched using different combinations of the following key words: PDT, oral precancer, leukoplakia, erythroplakia, erythroleukoplakia, verrucous hyperplasia, oral submucous fibrosis, and HNSCC. Review articles, experimental studies, case reports, commentaries, letters to the editor, unpublished articles, and articles published in languages other than English were excluded. Twenty-six studies were included in the present study. The number of patients ranged from 2 to 147, with a mean age of 50-67years. The reported numbers of PMDS and HNSCC ranged between 5 and 225. Photosensitizers used were aminolevulinic acid, meta-tetrahydroxyphenylchlorin, Foscan, hematoporphyrin derivatives, Photofrin, Photosan, and chlorine-e6. Laser wavelength, power density, irradiation duration were 585-652nm, 50-500mW/cm2 , and 1-143minutes, respectively. Complete, partial, and no response to PDT was found in 22.58%-100%, 4%-66%, and 0%-38.70% of PMDS, respectively, and 16%-100% of complete response in HNSCC patients. PDT is effective in the management of PMDS and HNSCC.

Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

Highly Effective Dual-Function Near-Infrared (NIR) Photosensitizer for Fluorescence Imaging and Photodynamic Therapy (PDT) of Cancer.

We report herein the synthesis and biological efficacy of near-infrared (NIR), bacteriochlorin analogues: 3-(1'-butyloxy)ethyl-3-deacetyl-bacteriopurpurin-18-N-butylimide methyl ester (3) and the corresponding carboxylic acid 10. In in vitro assays, compared to its methyl ester analogue 3, the corresponding carboxylic acid derivative 10 showed higher photosensitizing efficacy. However, due to drastically different pharmacokinetics in vivo, the PS 3 (HPLC purity >99%) showed higher tumor uptake and long-term tumor cure than 10 (HPLC purity >96.5%) in BALB/c mice bearing Colon 26 tumors. Isomerically pure R- and S- isomers of 3 (3a and 3b, purity by HPLC > 99%) under similar treatment parameters showed identical efficacy in vitro and in vivo. In addition, photosensitizer (PS) 3 showed limited skin phototoxicity and provides an additional advantage over the clinically approved chemically complex hematoporphyrin derivative as well as other porphyrin-based PDT agents, which makes 3 a promising dual-function agent for fluorescence-guided surgery with an option of phototherapy of cancer.

Forty-six cases of nasopharyngeal carcinoma treated with 50 Gy radiotherapy plus hematoporphyrin derivative: 20 years of follow-up and outcomes from the Sun Yat-sen University Cancer Center.

BackgroundWith the improved overall survival (OS) of nasopharyngeal carcinoma (NPC) patients, the importance of quality of life (QoL) is increasingly being recognized. For some radiosensitive NPC patients, whether low-dose radiotherapy can improve the QoL without affecting clinical efficacy is unknown. This study aimed to assess the survival rates and QoL of NPC patients treated with 50 Gy radiotherapy plus hematoporphyrin derivative (HPD).MethodsForty-six newly diagnosed NPC patients treated with 50 Gy radiotherapy plus HPD between June 1988 and July 1992 were analyzed. All patients were restaged according to the 7th edition of the American Joint Committee on Cancer staging system. The radiotherapy plan was designed on the basis of pretreatment computed tomography. The OS, local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) rates were estimated using the Kaplan–Meier method. QoL was assessed using the Late Radiation Morbidity Scoring Criteria of the Radiation Therapy Oncology Group.ResultsThe 5-year OS, LRFS, DMFS, and DFS rates were 74.3%, 72.6%, 82.1%, and 61.2%, respectively. The corresponding 10-year rates were 38.4%, 62.9%, 78.5%, and 49.8%, respectively, and the 20-year rates were 27.7%, 51.4%, 78.5%, and 40.7%, respectively. None of the patients developed severe radiation-related complications, such as radiation-induced temporal lobe necrosis, hearing loss, trismus, and dysphagia.ConclusionSome NPC patients were sensitive to 50 Gy radiotherapy plus HPD, and this sensitivity was characterized by long-term survival without significant late treatment morbidities.

Influence of Photodynamic Therapy on Apoptosis and Invasion of Human Cholangiocarcinoma QBC939 Cell Line.

To investigate the effect of photodynamic therapy (PDT) mediated by hematoporphyrin derivative (HPD) on apoptosis and invasion of cholangiocarcinoma QBC939 cell lines. In vitro cultured cholangiocarcinoma QBC939 cell line was exposed to 2, 4, 6, 8, 10, 12, and 14 μg/ml HPD with 5, 10, and 15 J/cm2 light intensity, respectively. The optical density at 450 nm of the QBC939 cells was measured by CCK8 assay and its growth inhibition ratio was calculated. Flow cytometry and transwell migration assay were applied to detect cell apoptosis and invasion respectively. RT-PCR and immunocytochemistry analyses were used to detect expressions of vascular endothelial growth factor-C (VEGF-C), cyclooxygenase-2 (COX-2), and proliferating cell nuclear antigen (PCNA). Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the secretion of VEGF-C and COX-2 in QBC939 cells. Exposure to HPD-PDT can significantly suppress the growth of QBC939 cells (all P<0.05). HPD-PDT can promote apoptosis of QBC939 cells at the early stage. When the concentration of HPD was 2 μg/ml and light irradiation was 5 J/cm2, HPD-PDT had no obvious inhibitory effect on QBC939 cell growth, but can obviously inhibit cell invasion, and significant difference was observed between the HPD-PDT and control groups (P<0.01). The HPD-PDT can reduce the mRNA and protein expressions of VEGF-C, COX-2, and PCNA, and decrease the secretion of VEGF-C and COX-2 in QBC939 cells. PDT could promote apoptosis and inhibit growth and invasion of cholangiocarcinoma cells QBC939 in vitro.

Photodecomposition, photomutagenicity and photocytotoxicity of retinyl palmitate under He–Ne laser photoirradiation and its effects on photodynamic therapy of cancer cells in vitro

ObjectiveOur aim was to study photodecomposition, photomutagenicity and cytotoxicity of retinyl palmitate (RP), a principal storage form of vitamin A in humans and animals, under He–Ne laser photoirradiation. Moreover, the effect of different concentrations and timing protocol of antioxidants on photodynamic therapy (PDT) is contradictory, so the effect of RP (as antioxidant) on the PDT cytotoxicity was studied. MethodsPhotomutagenicity was tested by Ames test. Photodecomposition was studied by UV–vis spectroscopy. Cytotoxicity was measured with MTT-assay. Moreover, the effect of PDT, using hematoporphyrin derivatives (HpD) as photosensitizer under He–Ne laser irradiation (10J/cm2), was studied on HeLa cells either with or without RP (1–100μM) which incubated with the cells for short or long incubation period (1h or 24h) prior to PDT. ResultsNo photodecomposition of RP alone was obseved whereas there is a little photodecomposition of RP only in presence of HpD under irradiation with He–Ne laser. Moreover, no photomutagenicity was observed in Salmonella typhimurium strains under laser irradiation in presence or absence of HpD. RP alone (1–100μM) significantly decrease the viability of HeLa cells. Laser irradiation of HeLa cells pre-incubated with RP alone for 24h showed further significant decrease in viability of the cells. While RP incubations for 1h before PDT had slight effect on the cells, 24h incubation before PDT enhanced the cytotoxicity of PDT on HeLa cells. ConclusionsRP can be used 24h before PDT to enhance its effects. RP is not mutagenic under irradiation with He–Ne laser.

Photodynamic therapy of human lung cancer xenografts in mice

BackgroundThere is a need to develop novel therapies for non-small cell lung cancer (NSCLC). Photodynamic therapy has been used successfully for endobronchial palliation of NSCLC, and its role in early stages of disease is being explored. We hypothesized that a novel photosensitizer, PS1, would be more effective than the standard agent, porfimer sodium (Photofrin or PFII), in treating human lung cancer xenografts in mice. Materials and methodsPatient-derived NSCLC xenografts were established subcutaneously in severe combined immune deficiency mice. Two groups of five mice were injected with PS1 (3-[1′-m-iodobenzyloxy]ethyl-3-devinylpyropheophorbide-a), a chlorophyll-a derivative, or PFII (a purified version of hematoporphyrin derivative) and then treated with nonthermal laser light. Four mice were treated with laser light without photosensitizer and six mice received no treatment at all. All mice were then observed for tumor growth. The tumor growth end point, time-to-1000 mm3, was evaluated using standard Kaplan–Meier methods and the log-rank test. Tumor hematoxylin and eosin and caspase 3 staining was done to evaluate necrosis and apoptosis. ResultsThe median time-to-1000 mm3 was 12, 12, 26, and 52 d for the control, light only, PFII, and PS1 groups. There was a significant association between the tumor growth end point and treatment (P < 0.05). Hematoxylin and eosin staining revealed <1%, 0%, 67%, and 80% necrosis, and caspase 3 positivity was 2%, <1%, 17%, and 39%, respectively, in the same four groups. ConclusionsThe mice treated with PS1 exhibited a longer time for tumor regrowth and showed more tumor necrosis and apoptosis compared with the other treatment groups. Thus, the novel photosensitizer, PS1, was demonstrated to be more effective than porfimer sodium in this preclinical pilot study.

Photodynamic efficiency of hypericin compared with chlorin and hematoporphyrin derivatives in HEp-2 and Vero epithelial cell lines

Hypericin (HY) is a photoactive aromatic dianthraquinone that is considered a potent photodynamic agent. In this study, hypericin and two other photosensitizers, a hematoporphyrin derivative (Photogem(®); PG) and a chlorin derivative (Photodithazine(®); PZ), were compared in terms of their phototoxicity toward two cell lines, HEp-2 and Vero. The median inhibitory concentration (IC(50)) of each of the photosensitizers was obtained after a 16.2J cm(-2) dose of irradiation at 630 ± 10 nm. The IC(50) values were 0.07 ± 0.01 (HY), 1.0 ± 0.2 (PZ), and 9 ± 1 μgmL(-1) (PG) in HEp-2 cells and 0.3 ± 0.1 (HY), 1.6 ± 0.2 (PZ) and 11 ± 1 μgmL(-1) (PG) in Vero cells, showing that HY is more phototoxic than the others when irradiated at 630 nm. If these results are analyzed, simultaneously, with the first-order constant for BSA tryptophan photooxidation, obtained by fluorescence decay (λ(excitation)=280 nm), which are 11×10(-3) min(-1)±1. 10(-3) min(-1) (HY), 10 × 10(-3) min(-1)±1 × 10(-3) min(-1) (PZ), and 6 × 10(-3)min(-1) ± 1×10(-3)min(-1) (PG), it is possible to infer that the photodynamic efficiency alone is not sufficient to explain the higher HY phototoxicity. The lipophilicity is also an important factor for an efficient target cell accumulation and was assessed for all sensitizers through the octanol-water partition coefficient (log P): 1.20 ± 0.02 (HY), -0.62 ± 0.03 (PZ), and -0.9 ± 0.2 (PG). The higher value for HY correlates well with its observed superior efficiency to promote damage at low concentrations and doses. As HY is used for the long-term treatment of mild depression, it is considered safe for humans. This fact and the present results reinforce the great potential of this photosensitizer to replace porphyrin derivatives, with the advantages that mean it could be used as photosensitizer in clinical photodynamic therapy.