Use of multiple photosensitizers and wavelengths during photodynamic therapy: a new approach to enhance tumor eradication

Several studies have examined the synergism of hyperthermia or chemotherapy agents in combination with photodynamic therapy (PDT) to enhance tumor eradication. In our unique approach to treatment, multiple photosensitizers and wavelengths were used: two photosensitizers, Photofrin II and meso-tetra-(4-sulfonatophenyl)-porphine (TPPS4), irradiated at the appropriate therapeutic wavelength for each photosensitizer. EMT-6 mammary tumors were induced in the flanks of BALB/c mice. The mice were assigned to a control group (50 mice) or treatment group (150 mice). All treatment animals and some control animals received photosensitizing drug (5 mg/kg of TPPS4, 5 mg/kg of Photofrin II, or 2.5 mg/kg of both TPPS4 and Photofrin II). All treatment animals and some control animals also received light treatment (630 nm for TPPS4 and/or 658 nm for Photofrin II). The results show that the approach using both drugs and the corresponding therapeutic wavelengths enhanced the effectiveness of PDT. This approach achieved a cure rate of up to 100%, which was, depending on the light intensity used, as much as 40% greater than the rate achieved by the approach using one drug and one wavelength. The results also show that lesser amounts of drug and/or light may be required if both drugs and wavelengths are used, thus lowering the chances of side effects common to PDT. Furthermore, the results indicate that the increased tumor kill is due to a synergistic effect of the two photosensitizers that was tested on the tumor microvasculature in the first few hours after PDT.     

Interaction of interstitial photodynamic therapy and interstitial hyperthermia in a rat rhabdomyosarcoma--a pilot study

Photodynamic therapy (PDT) involves the activation of photosensitizing drugs by light of appropriate wavelength. The photosensitive agent Hematoporphyrin Derivative (HPD) appears to be preferentially retained in malignant tumors; irradiation of HPD-containing tissue by light of appropriate wavelength (625 nm) and dose leads to (tumor) tissue destruction. The aim of this study is to achieve maximum tumor control probability with minimum normal tissue photosensitivity. In previous work from our laboratory it has been demonstrated that PDT has its fundamental effects on the tumor and normal tissue microcirculation. As it is well established that hyperthermia (HT) has its major effects in less well vascularized areas of the tumor, the combined modality of HT and PDT might prove to be advantageous. Moreover, suppression of sublethal damage repair by HT has been observed. To overcome the problem of poor light penetration into tissues and the high rate of recurrences following PDT with external irradiation, the combined effects of interstitial PDT with interstitial hyperthermia in a new line of animal experiments were studied in our laboratory. An experimental murine tumor (Rhabdomyosarcoma, type R-1) was transplanted in WAG/Rij rats and, after reaching an average diameter of 2 cm, the active component of HPD, that is Photofrin II, was injected intravenously in different dose schedules (5 mg/kg, 10 mg/kg). After 24 or 48 hrs the tumors were implanted with four flexible catheters, through which either light or heat could be applied. Light was obtained from an Argon-Dye laser system tuned to a wavelength of 625 nm at a dose rate of 75-100 mW per fiber to a dose level of 900 Joule from four linear light applicators. Heat (44 degrees C/30') was delivered by four 27 MHz radiofrequency antennas. Dose response relationships for PDT alone, HT alone and PDT combined with HT were established with cure as endpoint. This study showed that these two modalities, in the proper sequence and spacing, result in an augmented cytotoxicity on the tumor cells in vivo. With the combined modality treatment a cure rate of 41% (90 days) was obtained. As the implantation of flexible catheters is a well-known technique in radiation therapy practice, the potentiating effects of interstitial HT combined with interstitial PDT in solid tumors is very promising and clinical studies are warranted.     

Treatment with the tumor necrosis factor-alpha-inducing drug 5,6-dimethylxanthenone-4-acetic acid enhances the antitumor activity of the photodynamic therapy of RIF-1 mouse tumors

DMXAA (5,6-dimethylxanthenone-4-acetic acid) is an antivascular agent that exerts its antitumor effect at least partly through the induction of tumor necrosis factor (TNF)-alpha. Photodynamic therapy (PDT), the activation of a photoreactive drug in tumor tissue with visible light, is used clinically to control solid malignancies. PDT has been shown previously to be potentiated, in mice, by the i.p. administration of recombinant human TNF-alpha. Here, we investigated the activity of DMXAA as a modifier of Photofrin-based PDT of implanted murine RIF-1 tumors. The DMXAA dose (20 mg.kg(-1)) used throughout this study had little effect on tumor growth. The combination of DMXAA and PDT led to a reduction in tumor volume and significant delays in regrowth, giving a PDT-dose modification factor of 2.81. This enhancement was found to be strongly schedule dependent. The most pronounced responses were achieved when DMXAA was administered 1-3 h before the local illumination of the tumors; less activity was observed at other intervals within +/-24 h of PDT-light delivery. Using a 2-h DMXAA-light interval, histological examination showed significantly reduced blood vessel counts (CD31 immunostaining) and marked necrosis (H&E) in the tumors given combination therapy compared with the tumors given either agent alone. Conversely, peritumoral tissue was still intact 24 h after the combined therapy. DMXAA did not augment the damage to normal mouse feet after low-dose PDT (1.5 mg.kg(-1) Photofrin); however, there was some enhancement of normal tissue phototoxicity when DMXAA was combined with high-dose PDT. The antitumor effect after DMXAA plus low-dose PDT (1.5 mg.kg(-1) Photofrin) appeared to be dependent on TNF-alpha because neutralizing antibodies to this cytokine reduced the tumor response to control levels. DMXAA by itself induced TNF-alpha in RIF-1 tumors whereas PDT did not. However, the addition of PDT after DMXAA resulted in decreases in TNF-alpha, suggesting that the enhanced antitumor activity of the combination therapy was not attributable simply to an increased induction of the cytokine by PDT over that from DMXAA alone. These observations suggest a promising new combination therapy with considerable therapeutic advantage.     

Comparison of fluorescence and photodynamic activities of whole hematoporphyrin derivative and its enriched active components

The in vivo biologic activities of the hematoporphyrin derivative (Photofrin) and the enriched, so-called "active fraction" (Photofrin II) were determined by measuring the necrosis produced in implanted tumors in DBA/2Ha mice exposed to various total doses of light (20-100 J/cm2) after ip administration of 10 mg/kg standard doses of either Photofrin or Photofrin II. Total relative percentage increase in fluorescence in tumor tissue, as compared to fluorescence in control tissue, also was measured for both Photofrin and Photofrin II. In response to total light doses (630 nm) of 40-100 J/cm2, mice that received Photofrin had comparable amounts of tumor necrosis to those mice that received Photofrin II. At doses of 40-60 J/cm2, 80% tumor destruction resulted, and at 80-100 J/cm2, tumor destruction was 100%. However, at a total light dose of 20 J/cm2, the tumors that received Photofrin II exhibited 60-80% tumor necrosis, whereas those animals that received Photofrin had only small areas of patchy necrosis associated with signs of vascular thrombosis and hemorrhage into the surrounding perivascular stroma. A 25.2% total increase in maximal tissue fluorescence over that in controls was observed for animals that received Photofrin II, as compared to 13.9% for those animals that received Photofrin. It is concluded that the greater demonstrable efficacy of treatment with Photofrin II, as compared to treatment with Photofrin, is due to enrichment of those nonpolar hydrophobic components of the hematoporphyrin derivative mixture that are thought to be primarily responsible for the in vivo biologic activities.     

Depletion of tumor oxygenation during photodynamic therapy: detection by the hypoxia marker EF3 [2-(2-nitroimidazol-1[H]-yl)-N-(3,3,3-trifluoropropyl)acetamide

Photodynamic therapy (PDT) of tumors can create hypoxia when oxygen is depleted by photochemical consumption or the oxygen supply is compromised by microvascular damage. However, oxygen is a requirement for PDT, and hypoxia during illumination can lead to poorer tumor response. As such, sensitive methods of quantifying tumor oxygen and evaluating its distribution may help in the development and optimization of treatment protocols. In this study, the hypoxia marker EF3 [2-(2-nitroimidazol-1[H]-yl)-N-(3,3,3-trifluoropropyl)acetam ide] was used to evaluate the oxygenation of PDT-treated radiation-induced fibrosarcoma tumors. Tumor-bearing mice were administered Photofrin (5 mg/kg) 24 h before PDT illumination at 75 mW/cm2, 135 J/cm2 (30 min). EF3 (52 mg/kg) was injected either within 3 min before PDT illumination, with tumor excision at the conclusion of illumination, or within 3 min after illumination, with tumor excision 30 min later. Control animals received EF3 alone, EF3 plus Photofrin, or EF3 plus illumination. After tumor disaggregation, staining with a fluorochrome-conjugated monoclonal antibody, and flow cytometric analysis, control tumors demonstrated an averaged median fluorescence intensity (+/- SE) of 17.1 +/- 2.8. EF3 binding significantly (P = 0.007) increased during PDT to a median fluorescence intensity of 48.9 +/- 8.3. In the 30 min after PDT, EF3 binding returned to control levels (median, 18.3 +/- 3.3). To evaluate the oxygen concentrations corresponding to these fluorescence intensities, an in vitro standard curve was created based on the in vivo exposure conditions. From this curve, the oxygen tensions of tumors exposed to EF3 under control conditions, during PDT, or after PDT were calculated to be 3.1-5.3, 1.2-2.4, and 3.0-5.2 mm Hg, respectively. Detection of EF3 binding using a monoclonal antibody correlated well with direct detection of binding using a radioactive assay. EF3 binding was linear with drug incubation for times from 1.5 to 60 min. Overall, this work demonstrates that hypoxia during PDT illumination of radiation-induced fibrosarcoma tumors can be detected by the hypoxia marker EF3. Hypoxia during illumination can be labeled separately from that found before or after PDT. Tissue oxygen tensions corresponding to EF3 binding levels can be calculated.     

Ｐｈｏｔｏｆｒｉｎ光动力治疗舌癌的临床观察

目的　观察Ｐｈｏｔｏｆｒｉｎ光动力治疗舌癌的临床疗效和安全性。方法　２００３年７月至２００９年８月收治舌癌患者１４例,Ⅰ ～Ⅱ期４例,Ⅲ ～Ⅳ期１０例,所有舌癌患者均放弃或拒绝手术和放射治疗,并经病理确诊为高分化鳞癌。按２ｍｇ／ｋｇ静脉滴注光敏剂Ｐｈｏｔｏｆｒｉｎ,４８ｈ后经内镜导入光导纤维予波长６３０ｎｍ激光照射,照射方式分两种,即表面照射和组织间照射,治疗２４ｈ后清除坏死组织,并对深部肿瘤进行重复照射,治疗后１、３和６个月随访观察患者病灶的局部反应,并随访１４例患者的生存情况。结果　治疗后２４ｈ,病灶局部明显变暗、发紫,肿瘤组织坏死。舌癌患者光动力治疗总有效率为８５.７％,完全缓解率为２８.６％。获ＣＲ４例中Ⅰ期２例,Ⅱ、Ⅲ期各１例。１４例患者中位生存期为１３.５个月。结论　光动力治疗舌癌总有效率高,且耐受性好,早期舌癌患者可以保留语言功能并达到临床根治的目的,晚期患者可以明显改善生活质量,是一种较好的姑息治疗手段。     

Nuclear magnetic resonance spectroscopy and sensitizer-adduct measurements of photodynamic therapy-induced ischemia in solid tumors.

Dunning R3327-AT prostate carcinomas growing in Fischer X Copenhagen rats were treated with interstitial photodynamic therapy (PDT--15 mg/kg Photofrin II 4 hours before illumination with 630-nm light via four parallelly implanted optical fibers) at different light intensities. Forty to 60 minutes after treatment, 31P-nuclear magnetic resonance spectra of tumors in anesthetized animals were obtained at 2.35 Tesla using surface coil localization. Areas under resonance peaks were normalized to the area under the peak of a phosphorus standard positioned at a fixed distance on the opposite side of the surface coil. Tumor concentrations of phosphomonoesters and phosphodiesters showed no change after tumor light doses up to 3000 J. Phosphocreatine, alpha-adenosine triphosphate (ATP), beta-ATP, and gamma-ATP signals decreased and inorganic phosphate signals increased with increasing light doses. The intratumor pH did not change significantly at these short times after PDT. In other R3327-AT and R3327-H tumor-bearing animals, [3H]misonidazole was administered 30 minutes prior to PDT treatments of both tumors. Twenty-four hours later, the tumors were resected in toto, and levels of retained [3H]misonidazole were determined in lased tumor specimens by liquid scintillation procedures. The amount of [3H]misonidazole activity in tumor tissue (covalently bound after hypoxic reduction) increased with light doses up to 3000 J. Sensitizer-adduct formation was found to correlate with the ratio of the concentration of inorganic phosphate to that of beta-ATP, both of which are presumed measures of tumor oxygenation status. These measurements have high-lighted the heterogenous nature of the oxygenation status of these experimental tumors. The precision of each assay for estimating tumor oxygenation is discussed.     

The role of microvascular damage in photodynamic therapy: the effect of treatment on vessel constriction, permeability, and leukocyte adhesion.

Intravital microscopy of the rat cremaster muscle was used to evaluate changes in vessel constriction, vessel permeability, and leukocyte adhesion during and after photodynamic therapy (PDT). Animals were given Photofrin doses of 0-25 mg/kg i.v. 24 h before treatment. Cremaster muscles were exposed to 135 J/cm2 light at 630 nm. Animals given 5 mg/kg Photofrin showed no vessel constriction or increase in vessel permeability to albumin. Doses of 10 and 25 mg/kg Photofrin caused a dose-related constriction of arterioles which was observed within the first minutes of illumination at the higher drug dose. After the initial constriction, arteriole response to PDT was biphasic in nature, with some vessels relaxing to nearly control levels while others remained fully constricted. Constriction of venules occurred only at the highest porphyrin dose studied (25 mg/kg) and was delayed in comparison to arteriole constriction. Photofrin doses which produced arteriole constriction also caused an increase in venule permeability to albumin, which occurred shortly after the start of light treatment and was progressive with time. Leakage began at specific sites along the venule wall but became uniform along the entire length of the venule by 1 h after treatment. Changes in the adherence of polymorphonuclear leukocytes to venule endothelium were also observed with PDT. Photofrin doses of 25 mg/kg and 45 J/cm2 light were sufficient to cause polymorphonuclear leukocytes to become adherent to the vessel wall. A second group of animals was given indomethacin trihydrate to examine the involvement of cyclooxygenase products such as thromboxane in vessel response to PDT. Animals given 5 mg/kg indomethacin intraarterially 1 h before light treatment showed no constriction of arterioles or venules at all Photofrin and light doses studied. No increases in venule permeability to albumin were seen in this group of animals. This suggests that cyclooxygenase products including thromboxane are important in causing vessel constriction and changes in permeability during PDT. The initiating event which causes the release of these vasoactive agents remains unknown.     

Enhancement of photodynamic therapy by mitomycin C: a preclinical and clinical study.

Photodynamic therapy (PDT) using Photofrin was used in combination with a hypoxic toxin (mitomycin C, MMC) to treat four patients with recurrent skin metastasis of a mammary carcinoma. In preclinical experiments an additive effect was found for the combination of MMC and PDT for treating subcutaneous RIF1 tumours in mice. When interstitial PDT was combined with a low dose of MMC (administered 15 min before illumination), the Photofrin dose or light dose could be reduced by a factor of 2 in order to obtain equivalent cure rate or growth delay. In the clinical pilot study, a low dose of Photofrin (0.75 mg kg-1) was used for PDT alone (superficial illumination) or combined with low-dose MMC (5 mg m-2). Different tumour areas were illuminated with or without a preceding infusion of MMC. Both tumour response and skin photosensitivity were scored. After 8-12 weeks of treatment, tumour cure could be achieved by administering light doses > or = 150 J cm-2 for PDT alone and similar effects were obtained when light doses of 75-87.5 J cm-2 were given after infusion with MMC. In all cases necrotic tissue of both tumour and surrounding skin was observed, which lasted for a mean of 5 months (range 2-20 months). Skin phototoxicity, tested by using a standardised illumination of skin patches on the back, lasted maximally 3 weeks. Three main conclusions could be drawn from these studies: (1) The enhanced effects of the combination of PDT and MMC observed in mouse tumours can be extrapolated to patients with mammary skin metastasis. (2) The combination of PDT and hypoxic toxins facilitates treatment by permitting lower doses of photosensitiser to be used (thereby reducing skin phototoxicity) or lower light doses (thereby reducing illumination times and allowing the possibility to treat larger tumour areas). (3) Restoration of skin after PDT in previously treated tumour areas (chemotherapy, radiation therapy and surgery) is very low.     

Fractionated versus standard continuous light delivery in interstitial photodynamic therapy of dunning prostate carcinomas.

PURPOSE: The study aims to compare the standard/continuous light delivery with fractionated light delivery for interstitial photodynamic therapy (PDT) of prostate cancer. EXPERIMENTAL DESIGN: Dunning R3327 prostate tumor models were established in male syngeneic rats. When tumors reached approximately 3,000 mm3, animals were randomized to various treatment groups. Three hours after QLT0074 injection, tumors were illuminated by 690-nm light delivered by a computer-controlled switch, which sequentially directed light to one of the seven optical fibers in cycles. For comparison, tumors were treated with continuous illumination. Tumors treated with light-only served as control. Dynamic contrast-enhanced magnetic resonance imaging was used to monitor tumor perfusion changes before and after PDT. RESULTS: Tumor response (animal survival) to PDT with fractionated light delivery was PDT dose dependent in both tumor models. Rats bearing anaplastic tumor treated by fractionated light (PDT dose: 1.5 mg/kg QLT0074, 900 J light) had a median survival of 51 days with 25% tumor cures compared with that of 26 days with no tumor cure by continuous illumination (P = 0.015) and 14 days by light-only (P = 0.0001). Rats bearing well-differentiated tumor treated by fractionated light had a median survival of 82 days compared with 65 days by continuous illumination (P = 0.001) and 37 days by light-only. PDT with fractionated light generated a perfusion reduction of 80% compared with 52% for continuous illumination in well-differentiated tumors. CONCLUSIONS: Fractionated light delivery is more effective than continuous light delivery in PDT of prostate cancer (solid tumors). These results warrant further investigation in clinical trials.     

Phase I and pharmacokinetic study of photodynamic therapy for high-grade gliomas using a novel boronated porphyrin.

PURPOSE: To determine the recommended dose, toxicity profile, and pharmacokinetics of a novel boronated porphyrin (BOPP) for photodynamic therapy (PDT) of intracranial tumors. PATIENTS AND METHODS: BOPP was administered alone in increasing doses (0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg) preoperatively in patients with intracranial tumors undergoing postresection PDT until dose-limiting toxicity (DLT) was observed. RESULTS: Twenty-nine assessable patients with intracranial tumors received BOPP intravenously 24 hours before surgery. The recommended dose was 4 mg/kg. Dose escalation was limited by thrombocytopenia. The most common nonhematologic toxicity was skin photosensitivity. Pharmacokinetic parameters showed increased area under the plasma concentration-time curve and maximum concentration with increased dose. Tumor BOPP concentrations also increased with increased dose. CONCLUSION: BOPP at a dose of 4 mg/kg was well tolerated. DLT was thrombocytopenia, and photosensitivity was the only other toxicity of note. The efficacy of PDT using BOPP requires further exploration.     

Role of thromboxane and prostacyclin release on photodynamic therapy-induced tumor destruction

Thromboxane and prostacyclin levels in serum were measured following photodynamic therapy (PDT) to assess the role of these vasoactive agents on vascular damage and tumor destruction. Sprague Dawley rats were given injections i.v. of Photofrin II doses ranging from 0 to 25 mg/kg. Twenty-four h later, the right hindlimbs of animals bearing chondrosarcoma tumor or controls were exposed to 0-135 J/cm2 630 nm light. Serum concentrations of thromboxane and prostacyclin were determined by radioimmunoassay. A dose-response relationship was established between the amount of photosensitizer administered and the light dose delivered with the release of thromboxane immediately following PDT. Treatment of tumor induced higher levels of thromboxane than did the treatment of tumor-free tissue, suggesting that tumor is more sensitive to PDT-induced damage. The porphyrin and light doses found to induce the release of thromboxane into serum were the same as those required to evoke vascular stasis and tumor destruction. Prostacyclin release was not altered by PDT. The administration of indomethacin (10 mg/kg, i.p.) 3 h before light treatment was found to suppress the intravascular release of thromboxane at the highest porphyrin and light doses studied. Indomethacin treatment also inhibited PDT-induced vascular stasis and tumor destruction, suggesting that the release of thromboxane is linked to these events. Since prostacyclin levels in serum were unchanged following PDT treatment of tumor and controls, thromboxane release appears to be a specific response to PDT and may mediate the vascular stasis observed following PDT.     

Photofrin uptake in the tumor and normal tissues of patients receiving intraperitoneal photodynamic therapy.

PURPOSE: A phase II trial of Photofrin-mediated i.p. photodynamic therapy shown in a previous report limited efficacy and significant acute, but not chronic, toxicity. A secondary aim of this trial and the subject of this report is to determine Photofrin uptake in tumor and normal tissues. EXPERIMENTAL DESIGN: Patients received Photofrin, 2.5 mg/kg, i.v., 48 hours before debulking surgery. Photofrin uptake was measured by spectroflurometric analysis of drug extracted from tumor and normal tissues removed at surgery. Differences in drug uptake among these tissues were statistically considered using mixed-effects models. RESULTS: Photofrin concentration was measured in 301 samples collected from 58 of 100 patients enrolled on the trial. In normal tissues, drug uptake significantly (P<0.0001) differed as a function of seven different tissue types. In the toxicity-limiting tissue of intestine, the model-based mean (SE) Photofrin level was 2.70 ng/mg (0.32 ng/mg) and 3.42 ng/mg (0.24 ng/mg) in full-thickness large and small intestine, respectively. In tumors, drug uptake significantly (P=0.0015) differed as a function of patient cohort: model-based mean Photofrin level was 3.32 to 5.31 ng/mg among patients with ovarian, gastric, or small bowel cancer; 2.09 to 2.45 ng/mg among patients with sarcoma and appendiceal or colon cancer; and 0.93 ng/mg in patients with pseudomyxoma. Ovarian, gastric, and small bowel cancers showed significantly higher Photofrin uptake than full-thickness large and/or small intestine. However, the ratio of mean drug level in tumor versus intestine was modest (相似文献   

Interstitial photodynamic therapy in a rat liver metastasis model.

Photodynamic therapy (PDT) of hepatic tumours has been restricted owing to the preferential retention of photosensitizers in liver tissue. We therefore investigated interstitial tumour illumination as a means of selective PDT. A piece of colon carcinoma CC531 was implanted in the liver of Wag/Rij rats. Photofrin was administered (5 mg kg-1 i.v.) 2 days before laser illumination. Tumours with a mean (+/- s.e.) diameter of 5.7 +/- 0.1 mm (n = 106, 20 days after implantation) were illuminated with 625 nm light, at 200 mW cm-1 from a 0.5 cm cylindrical diffuser and either 100, 200, 400, 800 or 1600 J cm-1. Control groups received either laser illumination only, Photofrin only or diffuser insertion only. Short-term effects were studied on the second day after illumination by light microscopy and computer-assisted integration of the circumference of damaged areas. Long-term effects were studied on day 36. To determine the biochemistry of liver damage and function, serum ASAT and ALAT levels were measured on day 1 and 2, and antipyrine clearance on day 1. Tumour and surrounding liver necrosis increased with light dose delivered (P < 0.001). Best long-term results were obtained at 800 J cm-1 with complete tumour remission in 4 out of 6 animals. No deterioration in liver function was found. The results of this study show the ability of interstitial PDT to cause major destruction of tumour tissue in the liver combined with minimal liver damage.     

Atorvastatin reduces functional deficits caused by photodynamic therapy in rats

Clinical studies have indicated that photodynamic therapy (PDT) significantly prolonged the median survival of patients with gliomas. Experimental studies demonstrate that increasing optical energy and photosensitizer dose leads to increased volume of tumor necrosis. However, increasing the light dose delivered to the tumor may increase the risks of inducing permanent neurological deficits. In the current study, we sought to test the behavioral deficits induced in normal rats by brain PDT and the neurorestorative effects of atorvastatin on PDT-induced behavioral deficits. Considering its potential as a combination treatment of brain tumors, we investigated both in?vitro and in?vivo whether atorvastatin treatment promotes brain tumor growth. Non-tumored Fischer rats received PDT (n=18). Nine of the PDT-treated animals were treated with atorvastatin. Control animals underwent the same surgical procedure, but did not receive Photofrin and laser light. PDT-treated animals had significant behavioral deficits on days 2, 5, 7, 9 and 14 after PDT, compared with surgery controls. PDT-treated animals receiving atorvastatin displayed significantly ameliorated behavioral deficits on days 7, 9 and 14 after PDT, compared to PDT-treated rats. In?vitro tumor cell viability and growth were evaluated. Atorvastatin did not affect the growth of glioma cells. Fischer rats with intracranial 7-day-old 9L glioma tumor cell implantation were randomly subjected to no treatment, PDT alone, atorvastatin alone, or combined treatment with atorvastatin and PDT (6?rats/group). Our data indicate that atorvastatin did not promote tumor growth in either PDT treated and non-treated rats. However, atorvastatin significantly reduced the cell damage caused by PDT. To further test the mechanisms underlying the atorvastatin-mediated reduction of functional deficits, we investigated the effects of atorvastatin on angiogenesis and synaptogenesis. Our data demonstrate that atorvastatin significantly induced angiogenesis and synaptogenesis in the PDT-damaged brain tissue. Our data indicate that PDT induces functional deficits. Atorvastatin treatment promotes functional restoration after PDT, but does not promote glioma growth in?vitro and in?vivo. Atorvastatin reduces astrocyte and endothelial cell damage caused by PDT and induces angiogenesis and synaptogenesis after PDT. Thus consideration and further testing of the combination of atorvastatin and PDT for the treatment of glioma is warranted.     

Hypoxia and Photofrin uptake in the intraperitoneal carcinomatosis and sarcomatosis of photodynamic therapy patients.

PURPOSE: Response to photodynamic therapy depends on adequate tumor oxygenation as well as sufficient accumulation of photosensitizer in the tumor. The goal of this study was to investigate the presence of hypoxia and retention of the photosensitizer Photofrin in the tumors of patients with intra-abdominal carcinomatosis or sarcomatosis. EXPERIMENTAL DESIGN: Tumor nodules from 10 patients were studied. In nine of these patients, hypoxia was identified in histological sections of biopsied tumor after administration of the hypoxia marker 2-(2-nitroimidazol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5). In separate tumor nodules from 10 patients, Photofrin uptake was measured by fluorescence after tissue solubilization. RESULTS: Hypoxia existed in the tumors of five patients, with three of these patients demonstrating at least one severely hypoxic nodule. Physiological levels of oxygen were present in the tumors of four patients. An association between tumor size and hypoxia was not evident because some tumor nodules as small as approximately 2 mm in diameter were severely hypoxic. However, even these tumor nodules contained vascular networks. Three patients with severely hypoxic tumor nodules exhibited moderate levels of Photofrin uptake of 3.9 +/- 0.4 to 3.9 +/- 0.5 ng/mg (mean +/- SE). The four patients with tumors of physiological oxygenation did not consistently exhibit high tumor concentrations of Photofrin: mean +/- SE drug uptake among these patients ranged from 0.6 +/- 0.8 to 5.8 +/- 0.5 ng/mg. CONCLUSIONS: Carcinomatosis or sarcomatosis of the i.p. cavity may exhibit severe tumor hypoxia. Photofrin accumulation in tumors varied by a factor of approximately 10x among all patients, and, on average, those with severe hypoxia in at least one nodule did not demonstrate poor Photofrin uptake in separate tumor samples. These data emphasize the need for reconsideration of the generally accepted paradigm of small tumor size, good oxygenation, and good drug delivery because this may vary on an individual tumor basis.     

Radiation therapy combined with photofrin or 5-ALA: effect on Lewis sarcoma tumor lines implanted in mice. Preliminary results

AIMS AND BACKGROUND: Ionizing irradiation is a well-established therapeutic modality for cancer. Photodynamic therapy (PDT), especially with 5-ALA and Photofrin, is highly effective in some tumor types. Chemical modifiers, so-called radiosensitizers, are used in order to increase the efficacy of radiotherapy. Most of the known and routinely used radiosensitizers are not tumor selective, so that the normal tissue reaction toxicity is also increased. In the present study we investigated whether a porphyrin derivative that is currently used as a tumor-photosensitizing agent in photodynamic therapy (PDT) may also act as a tumor-specific radiosensitizer. MATERIALS AND METHODS: For our investigation we used Balb/c mice implanted with Lewis sarcoma and irradiated with 3 Gy combined with injection of 5-ALA or Photofrin at various concentrations before irradiation. RESULTS: 5-ALA had no effect as a radiosensitizer at any of the concentrations examined. Photofrin at a concentration of 5 mg/kg proved to be a chemical modifier of ionizing radiation, delaying tumor growth and reducing the overall tumor volume by about 50% after six days. CONCLUSION: Photofrin has marked efficacy as a radiosensitizer and can be used in the future as a selective tumor radiosensitizer.     

Interstitial hyperthermia using 27 MHz wire antennas and interstitial photodynamic therapy in a rat rhabdomyosarcoma: phantom and animal studies

This paper deals with the interaction of interstitial hyperthermia (HT) and interstitial photodynamic therapy (PDT). Its main focus, however, is on a newly developed heating system; phantom studies as well as temperature-response data obtained from the in vivo experiments are presented. Heat was delivered by thin, flexible wire antennas operating at a frequency of 27 MHz. Measurements in muscle-equivalent phantom with infrared thermography were performed. Uniform heating over the inserted length of the antenna was obtained and impedance matching appears possible by simple variable air coils, thereby minimizing the reflected power to less than 20%. Light was obtained from an Argon-Dye laser system tuned to a wavelength of 625 nm at a dose rate of 75-100 mW per fiber to a total incident dose of 900 J from four linear light applicators. An experimental murine tumor (Rhabdomyosarcoma, type R-1) was transplanted in WAG/Rij rats and, after reaching an average diameter of 2 cm, the active component of haematoporphyrin derivative (HPD), Photofrin II, was injected intravenously. The tumors were subsequently implanted with four flexible catheters, through which either light or heat could be applied. Dose-response relationships for PDT alone, HT alone and PDT followed by HT were established with cure as endpoint. The animal experiments showed that with the use of low-frequency wires a good localized heat distribution in the tumors can be obtained. Moreover, this study showed that PDT and HT, in the proper sequence and only when optimal temperatures are reached, result in an augmented cytotoxicity on the tumor cells in vivo; i.e. a cure rate of 41% was obtained.     

华卟啉钠介导的光动力疗法在体外和体内对肿瘤生长的抑制作用

目的： 观察华卟啉钠 (sinoporphyrin sodium,DVDMS-2)介导的光动力疗法 (DVDMS-2-PDT)在体内外对肿瘤生长的抑制作用及其强度。方法：用噻唑蓝(MTT)法检测DVDMS-2在体外对4种肿瘤细胞 (人肝癌细胞HepG2、人肺癌细胞H460、人胃癌细胞BGC823和人肾癌细胞Ketr-3)的生长抑制作用。采用小鼠肉瘤S180移植性肿瘤模型,按2 mg/kg单次尾静脉注射给予DVDMS-2,给药24 h后进行光动力治疗,分别设低、中、高剂量照射组 (分别为38、76、152 J/cm2),另设生理盐水阴性对照组和阳性对照组 (给予10 mg/kg Photofrin,按76 J/cm2进行光照射),实验结束后,称瘤质量,计算各组肿瘤生长抑制率。采用裸鼠H460细胞荷瘤动物模型,设DVDMS-2低、中、高剂量组 (分别为0.5、1.0、2.0 mg/kg),另设生理盐水阴性对照组和阳性对照组 (给予10 mg/kg Photofrin),激光照射条件为76 J/cm2 ,试验结束后,计算各组肿瘤质量、肿瘤体积、相对肿瘤增殖率T/C (%)等指标。利用SPSS 13.0对数据进行统计分析。结果：DVDMS-2对HepG2、H460、BGC823和Ketr-3细胞均有明显的生长抑制作用,MTT法测定其IC50值为0.207～0.584 μg/mL。小鼠肉瘤S180移植性肿瘤模型抑制实验中,低、中、高剂量照射组的平均肿瘤抑制率分别为82.83%、88.56%、95.59%,与阴性对照组比较,差异均具有统计学意义(P<0.05)。裸鼠H460细胞荷瘤动物模型中,DVDMS-2 0.5、1.0和2.0 mg/kg对裸鼠异体移植瘤的抑制率分别为38.8% 、47.9%和53.9%,与阴性对照组比较,差异均具有统计学意义(P <0.05)。结论：DVDMS-2体内外应用对肿瘤生长均有明显的抑制作用。     

Tumor and normal tissue response to interstitial photodynamic therapy of the rat R-1 rhabdomyosarcoma.

Interstitial photodynamic therapy (IPDT) using Photofrin II (PII) as photosensitizer has been studied in the rat rhabdomyosarcoma R-1, growing on the thigh or flank of WAG-Rij rats. A light dose-response relationship has been established, for 10 mg PII/kg i.v. and irradiation 24 hr later, with local tumor control as the end point for single IPDT treatments using four cylindrical diffusors simultaneously. A light energy fluence of 150-200 Joule/cm2 (wavelength 625 nm), measured in vivo at the tumor periphery, was required for tumor control. Comparison of tumor response at 5 and 2.5 mg PII/kg with the complete dose response relationship at 10 mg PII/kg suggests drug-light dose reciprocity and indicates that in our tumor model treatment failures are not likely to be caused by variations in (tumor) tissue photosensitizer level, but rather by insufficient light dose or inadequate light dose distribution. Increasing the interval between PII administration and irradiation from 24 hr to 48 hr had no great effect on tumor response to IPDT in this study. Inspection of the original tumor site 100 days after tumor control revealed obvious loss of thigh muscle tissue. Also, recurrent tumors showed a reduced growth rate. Therefore, the relationship between tumor (re)growth and PDT-induced normal tissue damage was studied and the existence of a tumor bed effect was confirmed. The present study indicates that tumor control after a single IPDT treatment is feasible, but that PDT induced damage to a margin of the adjacent normal tissue is probably required.