Combined photodynamic therapy and hyperbaric oxygenation in carcinoma of the esophagus and the esophago-gastric junction

Comparison effects of Ferula gummosa essential oil and Beta-pinene Alginate nanoparticles on human melanoma and breast cancer cells proliferation and apoptotic index in short term normobaric hyperoxic model

BACKGROUND

Breast cancer is the most common cancer among women, and melanoma is the most dreadful type of skin cancer. Due to the side effects of chemotherapy drugs, the development of new herbal nano-medicines has been considered.

METHODS

This study first investigated the chemical composition of Ferula gummosa essential oil using GC-MS analysis; β-pinene, with 61.57%, was the major compound. Next, alginate nanoparticles containing β-pinene and the essential oil with particle sizes of 174 ± 7 and 137 ± 6 nm were prepared. Meanwhile, their zeta potentials were 12.4 ± 0.7 and 28.1 ± 1 mV. Besides, the successful loading of β-pinene and the essential oil in nanoparticles was confirmed using ATR-FTIR analysis. After that, their effects on viability and apoptotic index of human melanoma and breast cancer cells were investigated in normoxia and normobaric hyperoxia (NBO) conditions.

RESULTS

The best efficacy on A-375 and MDA-MB-231 cells was achieved by alginate nanoparticles containing the EO at hyperoxic and normoxia conditions; IC50 76 and 104 µg/mL. Besides, it affected apoptosis-involved genes; as Bax/Bcl-2 ratio was higher than 1, conditions for induction of apoptosis were obtained. Higher sensitivity was observed in the A-375 cell line treated with Alg-EO in the NBO model.

CONCLUSIONS

Alginate nanoparticles containing F. gummosa EO could be considered for further investigation in anticancer studies. Also, it may be expected that NBO can be a new strategy for delaying cancer progression and improving nanotherapy efficacy.

Dual mode imaging guided multi-functional bio-targeted oxygen production probes for tumor therapy

Focused ultrasound ablation surgery (FUAS) is a novel therapy with a wide range of potential applications. However, synergists are crucial to the therapy process due to the ultrasonic energy's attenuation properties. As a result of the complex hypoxic environment in the tumor area and many factors, the existing synergists have limitations such as weak targeting, single imaging mode, and easy tumor recurrence after treatment. Because of the above deficiencies, this study intends to construct bio-targeted oxygen production probes consisting of Bifidobacterium that naturally target the hypoxia region of the tumor and multi-functional oxygen-producing nanoparticles equipped with IR780, perfluorohexane (PFH), CBP (carboplatin), and oxygen. The probes are expected to achieve targeted and synergistic FUAS therapy and dual-mode imaging to mediate tumor diagnosis and treatment. The oxygen and drugs carried in it are accurately released after FUAS stimulation, which is expected to alleviate tumor hypoxia, avoid tumor drug resistance, improve the effect of chemotherapy, and realize FUAS combined with chemotherapy antitumor therapy. This strategy is expected to make up for the deficiencies of existing synergists, improve the effectiveness and safety of treatment, and provide the foundation for future tumor therapy progress.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

Research progress of potential factors influencing photodynamic therapy for gastrointestinal cancer

Gastrointestinal cancer is a malignant tumor of the gastrointestinal tract and its associated digestive organs, including esophageal cancer, gastric cancer, carcinoma of the ampulla, pancreas, bile duct, intestines and rectal cancer. They account for about 30% of global cancer-related incidence and about 40% of mortality. Photodynamic therapy (PDT), as a treatment mode, has been applied to the treatment of gastrointestinal cancer due to potential advantages targeting and potentially lower toxic side effects. However, In the course of clinical treatment, we have found that different patients have various responsiveness to PDT, and even the same patients may have different clinical effects after receiving treatment in different time periods. For influencing factors, traditionally, we only focus on adjusting the dose of photosensitizer and the intensity and time of irradiation,while minimizing other potential factors.Therefore, this paper looks for factors that affect PDT from the patient's own conditions, tumor characteristics and tumor microenvironment(including:tumor acidic microenvironment,tumor hypoxic microenvironment, multi-drug resistance, different tumor characteristics and the immune status of patients) and summarizes how to potentially improve the curative effect of PDT.

Generation of singlet oxygen by porphyrin and phthalocyanine derivatives regarding the oxygen level

Background. The principle of photodynamic effect is based on the combined action of photosensitiser, molecular oxygen and light, which produce various reactive oxygen species and are associated with significant cellular damage. Singlet oxygen is one of the most serious representatives, which is characterised by powerful oxidising properties. Moreover, concomitant hyperbaric oxygen treatment can support these effects. Therefore, the subject of our study was to compare the yields of singlet oxygen for four different photosensitizers in dependency on the oxygen concentration. Material and methods. Four different photosensitizers 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate), tetramethylthionine chloride, 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin zinc(II) and zinc phthalocyanine disulfonate were investigated to determine the yield of singlet oxygen in PBS by Singlet Oxygen Sensor Green reagent under different partial pressures of oxygen (0.4 and 36 mg/l). Results. There were no noticeable shifts in the excitation and emission fluorescence spectra regarding the oxygen concentration. Concerning the same molar concentration of photosensitizers the production of singlet oxygen was highest for 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin zinc(II), where the rate of the fluorescence change was more than 3 times higher than that obtained for 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate). On the other hand, zinc phthalocyanine disulfonate showed the lowest yield in singlet oxygen production. Conclusions. Singlet oxygen production, within the range of oxygen concentrations achievable in tissues under normoxia or hyperoxia, does not depend on these concentrations. However, the singlet oxygen generation is significantly influenced by the type of photosensitizer, with the highest yield belonging to 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin zinc(II).

Overview of Nanoparticle-Based Approaches for the Combination of Photodynamic Therapy (PDT) and Chemotherapy at the Preclinical Stage

Simple Summary

The present review represents the outstanding and promising recent literature reports (2017–2022) on nanoparticle-based formulations developed for anticancer therapy with photodynamic therapy (PDT), photosensitizers, and chemotherapeutics. Besides brief descriptions of chemotherapeutics’ classification and of PDT mechanisms and limitations, several examples of nanosystems endowed with different responsiveness (e.g., acidic pH and reactive oxygen species) and peculiarity (e.g., tumor oxygenation capacity, active tumor targeting, and biomimetic features) are described, and for each drug combination, in vitro and in vivo results on preclinical cancer models are reported.

Abstract

The widespread diffusion of photodynamic therapy (PDT) as a clinical treatment for solid tumors is mainly limited by the patient’s adverse reaction (skin photosensivity), insufficient light penetration in deeply seated neoplastic lesions, unfavorable photosensitizers (PSs) biodistribution, and photokilling efficiency due to PS aggregation in biological environments. Despite this, recent preclinical studies reported on successful combinatorial regimes of PSs with chemotherapeutics obtained through the drugs encapsulation in multifunctional nanometric delivery systems. The aim of the present review deals with the punctual description of several nanosystems designed not only with the objective of co-transporting a PS and a chemodrug for combination therapy, but also with the goal of improving the therapeutic efficacy by facing the main critical issues of both therapies (side effects, scarce tumor oxygenation and light penetration, premature drug clearance, unspecific biodistribution, etc.). Therefore, particular attention is paid to the description of bio-responsive drugs and nanoparticles (NPs), targeted nanosystems, biomimetic approaches, and upconverting NPs, including analyzing the therapeutic efficacy of the proposed photo-chemotherapeutic regimens in in vitro and in vivo cancer models.

Presentation of Boerhaave's syndrome as an upper-esophageal perforation associated with a right-sided pleural effusion: A case report

BACKGROUND

Spontaneous esophageal rupture or Boerhaave's syndrome is a rare and acute disease with a high incidence of misdiagnosis and mortality. Here, we aimed to explore the clinical characteristics, diagnosis, treatment, and prognosis of spontaneous esophageal rupture, and to analyze the causes of misdiagnosis during the treatment of spontaneous esophageal rupture.

CASE SUMMARY

The clinical features of the patient with spontaneous esophageal rupture misdiagnosed earlier as pleural effusion were retrospectively analyzed and the reasons for misdiagnosis are discussed based on a current review of the literature. The patient was admitted to a local hospital due to shortness of breath accompanied by vomiting and abdominal distension for five hours. Based on the computed tomography (CT) scan analysis, clinically, right pleural effusion was diagnosed. However, the patient was unwilling to undergo right closed thoracic drainage. The patient also had intermittent fevers against infection, and during the course of treatment, he complained of chest pain, following which, he was transferred to our hospital. Grapefruit-like residue drainage fluid was observed. Re-examination of the chest CT scans suggested the presence of spontaneous perforation in the upper left esophagus. Therefore, the patient underwent an urgent esophageal hiatus repair. Unfortunately, the patient died of infection and respiratory failure due to progressive dyspnea after surgery.

CONCLUSION

Spontaneous esophageal rupture is a rare disease associated with high fatality. The patients do not present typical clinical symptoms and the disease progresses rapidly. This case report highlights the importance of a dynamic review of chest CT scan, not only for the initial identification of segmental injury but also for prioritizing subsequent treatment strategies. Moreover, we have presented some clues for clinicians to recognize and diagnose spontaneous esophageal rupture at rare sites (upper-esophageal segment) through this case report of spontaneous esophageal rupture that caused the patient's death. We have also summarized the reasons for the misdiagnosis and lessons learned.

Combination of tetrapyridylporphyrins and arene ruthenium(II) complexes to treat synovial sarcoma by photodynamic therapy

Four tetrapyridylporphyrin and four dipyridylporphyrin arene ruthenium complexes have been synthesized and characterized. In these complexes, the porphyrin core is either metal-free or occupied by zinc, and the arene ligand of the arene ruthenium units are either the standard methyl-isopropyl-benzene ([Formula: see text]cymene) or the less common phenylpropanol (PhPrOH) derivative. The porphyrin derivatives are coordinated to four arene ruthenium units or only two, in accordance with the number of pyridyl substituents at the periphery of the porphyrins, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (TPyP) and 5,15-diphenyl-10,20-di(pyridin-4-yl)porphyrin (DPhDPyP). All eight complexes were evaluated as anticancer agents on synovial sarcoma cells, in the presence and absence of light, suggesting that both the arene ligand and the porphyrin core substituent can play a crucial role in fine-tuning the photodynamic activity of such organometallic photosensitizers.

Clinical study of a 125I particle-integrated esophageal covered stent and hyperbaric oxygen in the treatment of advanced esophageal cancer

OBJECTIVE

this study aimed to investigate the clinical efficacy and feasibility of the treatment of advanced esophageal cancer with a combination of a 125I particle-integrated esophageal covered stent and hyperbaric oxygen.

METHODS

forty-five patients with advanced esophageal cancer were enrolled and were randomly divided into two groups: a treatment group and a control group. Patients in the treatment group were treated with a 125I particle-integrated esophageal covered stent and hyperbaric oxygen, while patients in the control group were treated with a 125I particle-integrated esophageal covered stent. The clinical effects and long-term survival time of the two groups were observed.

RESULTS

in the treatment group, the complete remission (CR) rate and partial remission (PR) rate of local lesions were 19.2 % and 61.5 %, respectively, and the total effective rate was 80.7 %. In the control group, the CR rate and PR rate of local lesions were 10.5 % and 52.6 %, respectively, and the total effective rate was 63.1 %. The total effective rate was higher in the treatment group than in the control group, which was statistically significant (p < 0.05).

CONCLUSION

the combination of a 125I particle-integrated esophageal covered stent and hyperbaric oxygen shows a good short- and long-term efficacy in the treatment of advanced esophageal cancer.

Advanced nanotechnology for hypoxia-associated antitumor therapy

Hypoxia is a hallmark of the tumor microenvironment, which promotes the proliferation, metastasis and invasion of tumors and stimulates the resistance of cancer treatments, leading to the serious consequence of tumor recurrence. Many nanotechnology-based studies have been conducted to improve the efficacy of cancer treatments using a hypoxia strategy. This is usually achieved by (i) activating bioreductive prodrugs in the tumor hypoxic/exacerbated hypoxic microenvironment, or (ii) delivering therapeutic agents to hypoxic tumor tissue using targeting molecules. Normally, a good therapeutic effect can be expected upon modulating the hypoxic microenvironment for tumor treatments. To achieve this, various nanotechnology strategies based on overcoming hypoxia have been exploited to alleviate tumor hypoxia and enhance the therapeutic efficacy of tumor therapy, including (i) reducing oxygen consumption by inhibiting cell respiration, (ii) normalizing tumor vessels to promote blood flow in the tumor, (iii) carrying exogenous oxygen into the tumor, and (iv) generating oxygen in situ. The strategy of in situ oxygen production is refined, and the scope of this strategy is further expanded. Finally, the inspiration of using advanced nanotechnology in hypoxia-associated antitumor therapy guides the study of tumor hypoxia for clinical use.

Fighting Hypoxia to Improve PDT

Photodynamic therapy (PDT) has drawn great interest in recent years mainly due to its low side effects and few drug resistances. Nevertheless, one of the issues of PDT is the need for oxygen to induce a photodynamic effect. Tumours often have low oxygen concentrations, related to the abnormal structure of the microvessels leading to an ineffective blood distribution. Moreover, PDT consumes O2. In order to improve the oxygenation of tumour or decrease hypoxia, different strategies are developed and are described in this review: 1) The use of O2 vehicle; 2) the modification of the tumour microenvironment (TME); 3) combining other therapies with PDT; 4) hypoxia-independent PDT; 5) hypoxia-dependent PDT and 6) fractional PDT.

Hyperbaric oxygen therapy and cancer--a review

Hypoxia is a critical hallmark of solid tumors and involves enhanced cell survival, angiogenesis, glycolytic metabolism, and metastasis. Hyperbaric oxygen (HBO) treatment has for centuries been used to improve or cure disorders involving hypoxia and ischemia, by enhancing the amount of dissolved oxygen in the plasma and thereby increasing O₂ delivery to the tissue. Studies on HBO and cancer have up to recently focused on whether enhanced oxygen acts as a cancer promoter or not. As oxygen is believed to be required for all the major processes of wound healing, one feared that the effects of HBO would be applicable to cancer tissue as well and promote cancer growth. Furthermore, one also feared that exposing patients who had been treated for cancer, to HBO, would lead to recurrence. Nevertheless, two systematic reviews on HBO and cancer have concluded that the use of HBO in patients with malignancies is considered safe. To supplement the previous reviews, we have summarized the work performed on HBO and cancer in the period 2004–2012. Based on the present as well as previous reviews, there is no evidence indicating that HBO neither acts as a stimulator of tumor growth nor as an enhancer of recurrence. On the other hand, there is evidence that implies that HBO might have tumor-inhibitory effects in certain cancer subtypes, and we thus strongly believe that we need to expand our knowledge on the effect and the mechanisms behind tumor oxygenation.

Photodynamic therapy for treatment of solid tumors--potential and technical challenges

Photodynamic therapy (PDT) involves the administration of photosensitizer followed by local illumination with visible light of specific wavelength(s). In the presence of oxygen molecules, the light illumination of photosensitizer can lead to a series of photochemical reactions and consequently the generation of cytotoxic species. The quantity and location of PDT-induced cytotoxic species determine the nature and consequence of PDT. Much progress has been seen in both basic research and clinical application in recent years. Although the majority of approved PDT clinical protocols have primarily been used for the treatment of superficial lesions of both malignant and non-malignant diseases, interstitial PDT for the ablation of deep-seated solid tumors are now being investigated worldwide. The complexity of the geometry and non-homogeneity of solid tumor pose a great challenge on the implementation of minimally invasive interstitial PDT and the estimation of PDT dosimetry. This review will discuss the recent progress and technical challenges of various forms of interstitial PDT for the treatment of parenchymal and/or stromal tissues of solid tumors.

The role of oxygen monitoring during photodynamic therapy and its potential for treatment dosimetry

Understanding of the biology of photodynamic therapy (PDT) has expanded tremendously over the past few years. However, in the clinical situation, it is still a challenge to match the extent of PDT effects to the extent of the disease process being treated. PDT requires drug, light and oxygen, any of which can be the limiting factor in determining efficacy at each point in a target organ. This article reviews techniques available for monitoring tissue oxygenation during PDT. Point measurements can be made using oxygen electrodes or luminescence-based optodes for direct measurements of tissue pO2, or using optical spectroscopy for measuring the oxygen saturation of haemoglobin. Imaging is considerably more complex, but may become feasible with techniques like BOLD MRI. Pre-clinical studies have shown dramatic changes in oxygenation during PDT, which vary with the photosensitizer used and the light delivery regimen. Better oxygenation throughout treatment is achieved if the light fluence rate is kept low as this reduces the rate of oxygen consumption. The relationship between tissue oxygenation and PDT effect is complex and remarkably few studies have directly correlated oxygenation changes during PDT with the final biological effect, although those that have confirm the value of maintaining good oxygenation. Real time monitoring to ensure adequate oxygenation at strategic points in target tissues during PDT is likely to be important, particularly in the image guided treatment of tumours of solid organs.

Hyperbaric oxygen therapy for malignancy: a review

One unique feature of tumors is the presence of hypoxic regions, which occur predominantly at the tumor center. Hypoxia has a major impact on various aspects of tumor cell function and proliferation. Hypoxic tumor cells are relatively insensitive to conventional therapy owing to cellular adaptations effected by the hypoxic microenvironment. Recent efforts have aimed to alter the hypoxic state and to reverse these adaptations to improve treatment outcome. One way to increase tumor oxygen tensions is by hyperbaric oxygen (HBO) therapy. HBO therapy can influence the tumor microenvironment at several levels. It can alter tumor hypoxia, a potent stimulus that drives angiogenesis. Hyperoxia as a result of HBO also produces reactive oxygen species, which can damage tumors by inducing excessive oxidative stress. This review outlines the importance of oxygen to tumors and the mechanisms by which tumors survive under hypoxic conditions. It also presents data from both experimental and clinical studies for the effect of HBO on malignancy.

The effect of hyperbaric oxygen therapy on tumour growth in a mouse model of colorectal cancer liver metastases

BACKGROUND AND AIMS

Hyperbaric oxygen (HBO) therapy involves the administration of 100% oxygen at high pressure. It has been used to treat a variety of conditions including non-healing wounds, carbon monoxide poisoning, and as an adjuvant to radiotherapy or chemotherapy. The effect of HBO alone on the growth of malignancy remains controversial. This study investigates the impact of HBO on tumour growth, kinetics and microcirculation of colorectal cancer liver metastases in an experimental model.

METHODS

Male CBA mice were induced with colorectal liver metastases via an intrasplenic injection of a murine derived colorectal cell line. Tumours were examined using quantitative stereological analysis, histology and scanning electron microscopy of microvascular resin casts. The effect of HBO on tumour proliferation and apoptosis was quantified using immunohistochemistry.

RESULTS

Daily exposure to HBO at 2.4 atm for 90 min had no effect on the volume of liver metastases. At day 13, HBO caused a significant reduction in tumour necrosis and proliferation compared to the non-HBO group (p=0.002 and p=0.008, respectively). By day 25 however, no differences were observed (p>0.05). No differences in apoptosis or microvascular architecture were observed.

CONCLUSION

HBO did not have a tumour stimulatory effect on colorectal liver metastases and may potentially be used safely in conjunction with other therapeutic treatment modalities.

Fractionated photodynamic therapy for a human oral squamous cell carcinoma xenograft

The aim of this study was to define the appropriate fractionation interval between photodynamic therapies (PDTs) for enhanced anti-tumour effects on human oral squamous cell carcinoma (HOSCC). Reoxygenation of HOSCC and the proliferative kinetics of the tumour cells following PDT exposure were evaluated in terms of immunohistochemical expression of vascular endothelial growth factor (VEGF) and the proliferating cell nuclear antigen (PCNA). The immunohistochemical expression of VEGF was quantitatively determined by computer-assisted image analysis. The VEGF expression and the PCNA labeling indices (LIs) of the tumour cells were assessed at varying time intervals after PDT. No significant differences were observed in PCNA LIs between the control group and experimental groups at 24, 48, and 72 h after PDT. The expression of VEGF after PDT exposure was demonstrated to be higher in the experimental group at 6 h than the control group, and then was comparable at 24 h between the both groups. These results indicate that the tumour cells surviving from PDT have proliferative potential, and that oxygenation in tumours subjected to PDT may be recovered after 24 h. In the next experiment, two protocols of laser irradiation in PDT were assessed on the basis of tumour volume between fractionated exposure with a 24-h interval and continuous exposure. Regrowth of the tumour was significantly suppressed by fractionated PDT. We propose here that fractionated light exposure with a 24-h interval should be utilized in PDT for an enhanced anti-tumour effect.

Phototherapy and malignancy: Possible enhancement by iron administration and hyperbaric oxygen

Photodynamic therapy (PDT) is a new therapeutic approach for the treatment of malignant tumors. Hyperbaric oxygen (HBO(2)) shows beneficial effects in various modalities of cancer interventions. Tumor cells tend to accumulate large amount of iron. There is interaction between tissue content of oxygen, iron, free radical production and tissue damage. Accumulation of intracellular iron is necessary for the production of oxygen radicals. HBO(2) increases tissue oxygen and hydrogen peroxide production in the cells. Malignant cells require iron, and exhibit more transferrin receptors. The photodynamic sensitization of human leukemic cells is achieved with accumulation of porphyrins stimulated by 5-aminolaevulanic acid (ALA) plus hemin. Further, a significant improvement in tumor response is obtained when PDT is delivered during hyperoxygenation. When PDT is combined with hyperoxygenation, the hypoxic condition is improved and the cell killing rate at various time points after PDT is significantly enhanced. Photosensitization with use of porphyrins is used with HBO(2) and PDT for treatment of certain tumors. PDT with ALA is used for treatment of actinic keratosis (AK). The combination of iron administration (by injection or oral rout), hemin, or transferrin, as a source for iron, HBO(2) as a source of oxygen under pressure and PDT as a source of generating free-radical tissue damage may be useful in the treatment of tumors. The possibility of combining HBO(2), iron, light and local photosensitizers to overcome skin tumors deserve extensive laboratory and clinical research work. Conclusively, iron, HBO(2), and PDT may have synergistic effect to hamper tumor cells.

Local physiological changes during photodynamic therapy

BACKGROUND AND OBJECTIVE

Herein an overview is provided of the causes, consequences, and significance of photodynamic therapy (PDT)-mediated effects on tumor oxygenation and blood flow during illumination.

STUDY DESIGN/MATERIALS AND METHODS

Techniques particularly valuable to this research have included tissue oxygen tension measurement by the Eppendorf pO2 Histograph; spatial quantification of hypoxia by EF3 and EF5; and tissue oxygenation/blood flow monitoring by diffuse reflectance/correlation spectroscopy.

RESULTS

Severe hypoxia was measured in vivo during PDT and is shown to be a consequence of photochemical oxygen consumption and/or compromised vascular perfusion. Oxygen depletion can be controlled by treatment regimen, occurs in a spatially-definable pattern, and is therapy-limiting. PDT-induced changes in tumor oxygenation during illumination are correlated with outcome. In PDT-treated tissues, blood flow also is determined by treatment regimen and correlates with treatment response.

CONCLUSIONS

Photodynamic therapy creates distinct, measurable changes in tumor oxygen and blood flow during illumination. These physiological changes may ultimately affect treatment efficacy.

Loss of E-cadherin mediated cell-cell adhesion as an early trigger of apoptosis induced by photodynamic treatment

Photodynamic treatment with different photosensitizers (PSs) can result in the specific induction of apoptosis in many cell types. It is commonly accepted that this apoptotic response depends on the mitochondrial accumulation of the PS. Accumulation in other cellular organelles, such as lysosomes or the Golgi complex, and subsequent photodamage resulting in an apoptotic process has been also described. However, the role played by cell adhesion in apoptosis induced in epithelial cells after photodynamic treatment is not well characterized. Here, we have used a murine keratinocyte line, showing a strong dependence on E-cadherin for cell-cell adhesion and survival, to analyze the relevance of this adhesion complex in the context of zinc(II)-phthalocyanine (ZnPc) photodynamic treatment. We report that under apoptotic conditions, ZnPc phototreatment induces a rapid disorganization of the E-cadherin mediated cell-cell adhesion, which largely preceded both the detachment of cells from the substrate, via beta-1 integrins and the induction of apoptotic mitochondrial markers. Therefore, the alteration in E-cadherin, alpha- and beta-catenins adhesion proteins preceded the release of cytochrome c (cyt c) from mitochondria to the cytosol and the activation of caspase 3. In addition, blocking E-cadherin function with a specific antibody (Decma-1) induced apoptosis in this cell system. These results strongly suggest that the E-cadherin adhesion complex could be the primary target of ZnPc phototreatment, and that loss of E-cadherin mediated cell adhesion after early photodamage triggers an apoptotic response.

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Hyperbaric oxygen alone or combined with 5-FU attenuates growth of DMBA-induced rat mammary tumors

We tested the hypothesis that hyperbaric oxygen (HBO) alone and with chemotherapy (5-FU) attenuates tumor growth of DMBA-induced tumors in rats. Six series were performed: (1) Controls (air and vehicle 0.9% NaCl i.p.), (2) 5-FU (0.2 mg/kg i.p.), (3) HBO (2 bar for 90 min and vehicle), (4) HBO and 5-FU, (5) HBO (11 days) and air (next 12 days), (6) HBO (23 days). All treatments were applied on days 1, 4, 7, 10 (Series 1-4), as well as on days 14, 17 and 23 (Series 5-6). Tumor diameter increased by 76.7 and 41.2% in untreated controls and in the 5-FU group, respectively, after 10 days. Tumor size fell by 17-24.2% in the HBO groups and by 35.5% when combined with 5-FU (P < 0.05 compared to HBO). HBO treatment reduced the total number of blood vessels in the tumors. After completion of HBO treatment tumor size increased, but statistically insignificant, during the next 12 days.

Photodynamic therapy for esophageal cancer: a useful and realistic option

The use of light therapy for tissue destruction is highly attractive for the endoscopic and minimally invasive therapy of esophageal cancer. Photodynamic therapy (PDT) offers the possibility of palliation of advanced obstructing tumors. However, there are other competing techniques, which can be used to open the esophageal lumen. It has also proved very effective in providing prolonged palliation of patients with advanced irresectable cancer. Completely obstructing tumors, tortuous and long lesions, and tumors near the upper end of the esophagus are particularly suitable for photodynamic therapy. Patients with obstruction to an esophageal prosthesis are also well palliated with PDT. A more interesting and exciting development is its use for the eradication of early asymptomatic mucosal disease. Photodynamic therapy is particularly useful for the eradication of field cancerous change in patients with pre-malignant Barrett's esophagus, or early tumors in patients unfit for radical therapy.

Improvement of tumor response by manipulation of tumor oxygenation during photodynamic therapy

Photodynamic therapy (PDT) requires molecular oxygen during light irradiation to generate reactive oxygen species. Tumor hypoxia, either preexisting or induced by PDT, can severely hamper the effectiveness of PDT. Lowering the light irradiation dose rate or fractionating a light dose may improve cell kill of PDT-induced hypoxic cells but will have no effect on preexisting hypoxic cells. In this study hyperoxygenation technique was used during PDT to overcome hypoxia. C3H mice with transplanted mammary carcinoma tumors were injected with 12.5 mg/kg Photofrin and irradiated with 630 nm laser light 24 h later. Tumor oxygenation was manipulated by subjecting the animals to 3 atp (atmospheric pressure) hyperbaric oxygen or normobaric oxygen during PDT light irradiation. The results show a significant improvement in tumor response when PDT was delivered during hyperoxygenation. With hyperoxygenation up to 80% of treated tumors showed no regrowth after 60 days. In comparison, when animals breathed room air, only 20% of treated tumors did not regrow. To explore the effect of hyperoxygenation on tumor oxygenation, tumor partial oxygen pressure was measured with microelectrodes positioned in preexisting hypoxic regions before and during the PDT. The results show that hyperoxygenation may oxygenate preexisting hypoxic cells and compensate for oxygen depletion induced by PDT light irradiation. In conclusion, hyperoxygenation may provide effective ways to improve PDT efficiency by oxygenating both preexisting and treatment-induced cell hypoxia.

Photosensitization with hematoporphyrin derivative compared to 5-aminolaevulinic acid for photodynamic therapy of esophageal carcinoma

BACKGROUND

Hematoporphyrin derivatives (HpD) as sensitizers for photodynamic therapy (PDT) in advanced esophageal cancer carry the risk of prolonged photosensitivity of the skin. New sensitizers such as 5-aminolaevulinic acid (ALA) with low rates of skin phototoxicity appear to be promising alternatives. The aim of this study was to evaluate the efficacy of ALA compared with HpD for PDT in advanced esophageal carcinoma regarding phototoxicity of the skin, reduction of dysphagia, tumor stenosis and length, and Karnovsky performance status.

METHODS

After diagnostic workup, photosensitization was done in 22 patients with ALA (60 mg/kg body weight, oral, 6 to 8 hours before PDT) and in 27 patients with a hematoporphyrin derivative (2 mg/kg body weight, intravenously, 48 hours before PDT). The light dose was calculated as 300 J/cm fiber tip. Light at 630 nm was applied using a pumped dye laser. In both groups, additional hyperbaric oxygenation was applied at a level of 2 absolute atmospheric pressure.

RESULTS

Improvement regarding dysphagia, stenosis diameter, and tumor length could be obtained in both treatment arms with a significant difference in favor of the HpD group (p = 0.02; p = 0.0000; and p = 0.000014, respectively). A questionnaire of patients in the HpD group confirmed that the ability of swallowing a meal was superior compared with the discomfort from limitation to sun exposure. No sunburn or other major treatment-related complication occurred in both treatment arms.

CONCLUSIONS

Despite the limitations of a nonrandomized study, photosensitzation with HpD seems to be more effective in PDT of advanced esophageal carcinoma compared with ALA.