Advantages of laserphyrin compared with photofrin in photodynamic therapy for bile duct carcinoma

Enhancing Cancer Treatment Through Combined Approaches: Photodynamic Therapy in Concert with Other Modalities

This review explores the role of photodynamic therapy (PDT) as an adjunctive treatment for cancers, with a focus on its potential to enhance the effects of established therapies like chemotherapy, surgery, and radiotherapy. Given the limitations of conventional cancer treatments, PDT's ability to improve therapeutic outcomes through combination strategies is examined. In cancers such as lung, breast, cholangiocarcinoma, and cervical, PDT shows promise in enhancing response rates, reducing recurrence, and minimizing adverse effects when used alongside standard modalities. This study highlights current findings on PDT's mechanisms in complementing chemotherapy, augmenting surgical precision, and enhancing radiotherapeutic effects, thus offering a multi-faceted approach to cancer treatment. Additionally, insights into the clinical application of PDT in these cancers emphasize its potential for reducing tumor resistance and supporting more effective, personalized care. By providing an overview of PDT's synergistic applications across diverse cancer types, this review underscores its emerging significance in oncology as a tool to address traditional treatment limitations. Ultimately, this review aims to inform and inspire researchers and clinicians seeking to refine and innovate cancer therapy strategies through PDT integration, contributing to the advancement of more effective, synergistic cancer treatments.

Research Progress of Natural Product Photosensitizers in Photodynamic Therapy

Photodynamic therapy is a noninvasive cancer treatment that utilizes photosensitizers to generate reactive oxygen species upon light exposure, leading to tumor cell apoptosis. Although photosensitizers have shown efficacy in clinical practice, they are associated with certain disadvantages, such as a certain degree of toxicity and limited availability. Recent studies have shown that natural product photosensitizers offer promising options due to their low toxicity and potential therapeutic effects. In this review, we provide a summary and evaluation of the current clinical photosensitizers that are commonly used and delve into the anticancer potential of natural product photosensitizers like psoralens, quinonoids, chlorophyll derivatives, curcumin, chrysophanol, doxorubicin, tetracyclines, Leguminosae extracts, and Lonicera japonica extract. The emphasis is on their phototoxicity, pharmacological benefits, and effectiveness against different types of diseases. Novel and more effective natural product photosensitizers for future clinical application are yet to be explored in further research. In conclusion, natural product photosensitizers have potential in photodynamic therapy and represent a promising area of research for cancer treatment.

Recent Advances in Photodynamic Imaging and Therapy in Hepatobiliary Malignancies: Clinical and Experimental Aspects

The therapeutic and diagnostic modalities of light are well known, and derivative photodynamic reactions with photosensitizers (PSs), specific wavelengths of light exposure and the existence of tissue oxygen have been developed since the 20th century. Photodynamic therapy (PDT) is an effective local treatment for cancer-specific laser ablation in malignancies of some organs, including the bile duct. Although curability for extrahepatic cholangiocarcinoma is expected with surgery alone, patients with unresectable or remnant biliary cancer need other effective palliative therapies, including PDT. The effectiveness of PDT for cholangiocarcinoma has been reported experimentally or clinically, but it is not the standard option now due to problems with accompanied photosensitivity, limited access routes of irradiation, tumor hypoxia, etc. Novel derivative treatments such as photoimmunotherapy have not been applied in the field hepatobiliary system. Photodynamic diagnosis (PDD) has been more widely applied in the clinical diagnoses of liver malignancies or liver vascularization. At present, 5-aminolevulinic acid (ALA) and indocyanine green (ICG) dyes are mainly used as PSs in PDD, and ICG has been applied for detecting liver malignancies or vascularization. However, no ideal tools for combining both PDD and PDT for solid tumors, including hepatobiliary malignancies, have been clinically developed. To proceed with experimental and clinical trials, it is necessary to clarify the effective photosensitive drugs that are feasible for photochemical diagnosis and local treatment.

Light Sources and Dosimetry Techniques for Photodynamic Therapy

Effective treatment delivery in photodynamic therapy (PDT) requires coordination of the light source, the photosensitizer, and the delivery device appropriate to the target tissue. Lasers, light-emitting diodes (LEDs), and lamps are the main types of light sources utilized for PDT applications. The choice of light source depends on the target location, photosensitizer used, and light dose to be delivered. Geometry of minimally accessible areas also plays a role in deciding light applicator type. Typically, optical fiber-based devices are used to deliver the treatment light close to the target. The optical properties of tissue also affect the distribution of the treatment light. Treatment light undergoes scattering and absorption in tissue. Most tissue will scatter light, but highly pigmented areas will absorb light, especially at short wavelengths. This review will summarize the basic physics of light sources, and describe methods for determining the dose delivered to the patient.

Two cases of bile duct carcinoma patients who underwent the photodynamic therapy using talaporfin sodium (Laserphyrin®)

The efficacy of adjuvant photodynamic therapy (PDT) using the new photosensitizer, talaporfin sodium (TPS) has been clinically examined in some patients with bile duct carcinoma (BDC). Based on our previous cohorts, a prospective clinical trial was attempted; however, only two cases were ultimately enrolled in 27 months. A 664-nm semiconductor laser (100 J/cm²) was applied through an endoscope to the tumor lesion within 6 h of an intravenous injection of 40 mg/m² TPS according to the protocol for lung cancer. Case 1 was an 82-y.o. female patient with BDC at the left hepatic duct with biliary obstruction, percutaneous transhepatic biliary drainage (PTBD) was achieved, and the patient did not consent to surgery. She was followed up for 15 months to search for non-surgical treatments and eventually received PDT. Although mild photosensitivity occurred, she was discharged without severe adverse events. Biliary stenosis markedly extended and a PTBD tube was scheduled at 1 month. However, cancer immediately metastasized to the liver and she died 155 days after PDT. Case 2 was a 70-y.o. female with perihilar BDC and multiple biliary stenoses. Multiple biliary stenting was considered to be difficult. She received PDT and no adverse events were observed. Biliary stenoses markedly improved and multiple stenting was successfully performed. On day 132, she died of cancer progression. These two cases demonstrated the safety and efficacy of biliary malignant stenosis soon after PDT; however, long-term survival and a sufficient quality of life were not achieved. The combination of the PDT protocol and system chemotherapy or brachytherapy needs to be examined in clinical trials for advanced stage BDC.

Current status of photodynamic therapy in digestive tract carcinoma in Japan

Photodynamic therapy (PDT) is an effective local treatment modality as a cancer-specific laser ablation in malignancy of some organs including digestive tracts or bile duct. In Japan, PDT has been applied at the early period after the first clinical induction in 1980’s. Although the useful efficacy was clarified, PDT has not been fully applied because of the phototoxicity of the porfimer sodium. The next generated talaporfin-sodium was used for PDT, in which phototoxicity was reduced and, however, the clinical efficacy for digestive tract malignancy has not yet been clarified. By proceeding the experimental and clinical trials, it is necessary to clarify the evidence of efficacy as a local powerful treatment with the conventional surgery, brachiotherapy and chemotherapy in the future step.

How to access photodynamic therapy for bile duct carcinoma

BACKGROUND

Photodynamic therapy (PDT) is a promising treatment option for local control of remnant cancer after surgical resection or biliary stenosis by the unresectable tumor in patients with bile duct carcinomas (BDC). To achieve effective tumor necrosis, an appropriate approach to laser irradiation is necessary.

METHODS

The efficacy of endoscopy-guided PDT using porfimer (n=12) or talaporfin sodium (n=13) was investigated by evaluating the transhepatic biliary routes and endoscopic retrograde biliary (ERB) routes in 25 patients with BDC.

RESULTS

Diseases included perihilar intrahepatic cholangiocarcinoma (ICC) in four patients, extrahepatic BDCs in 19 and ampular carcinoma (AC) in two patients. Adjuvant PDT after surgical resection was performed in 18 patients, and PDT for tumor biliary stenosis was performed in seven. In patients undergoing surgical resections, the mean period between the operation and PDT was 87±42 days. In patients who underwent prior surgical resections, the transhepatic route was used in five (28%), the jejunal loop was used in 11 (61%), the T-tube route was used in one, and the endoscopic retrograde cholangiography (ERC) route via papilla Vater was used in one. In unresectable BDC, the ERC route was used in four patients (57%), and the transhepatic biliary route was used in three (43%). Endoscopic-guided PDT could not be performed in one patient because of a technical failure. Except for the complication of photosensitivity, endoscopy-related complications were not observed in any patients. Patients undergoing PDT with porfimer sodium had a significantly longer admission period compared to patients undergoing PDT with talaporfin sodium (36 vs. 5 days, respectively) (P<0.01).

CONCLUSIONS

PDT was safely and definitively performed using the endoscopy-guided approach via the transhepatic or ERC route. By considering the disadvantages of both routes, PDT must be adequately achieved for local control of BDC.

Defensive mechanism in cholangiocarcinoma cells against oxidative stress induced by chlorin e6-based photodynamic therapy

In this study, the effect of chlorin e6-based photodynamic therapy (Ce6-PDT) was investigated in human intrahepatic (HuCC-T1) and extrahepatic (SNU1196) cholangiocarcinoma (CCA) cells. The amount of intracellular Ce6 increased with increasing Ce6 concentration administered, or with incubation time, in both cell lines. The ability to take up Ce6 and generate reactive oxygen species after irradiation at 1.0 J/cm² did not significantly differ between the two CCA cell types. However, after irradiation, marked differences were observed for photodamage and apoptotic/necrotic signals. HuCC-T1 cells are more sensitive to Ce6-PDT than SNU1196 cells. Total glutathione (GSH) levels, glutathione peroxidase and glutathione reductase activities in SNU1196 cells were significantly higher than in HuCC-T1 cells. With inhibition of enzyme activity or addition of GSH, the phototoxic effect could be controlled in CCA cells. The intracellular level of GSH is the most important determining factor in the curative action of Ce6-PDT against tumor cells.

Mitochondrial reactive oxygen species accelerate the expression of heme carrier protein 1 and enhance photodynamic cancer therapy effect

Photodynamic therapy using hematoporphyrin and its derivatives is clinically useful for cancer treatments. It has been reported that cancer cells incorporate hematoporphyrin and its derivatives via heme carrier protein 1, which is a proton-coupled folate transporter. However, the mechanism of this protein expression has not been elucidated. In general, the concentration of reactive oxygen species in cancer cells is higher than that in normal cells. We previously reported that reactive oxygen species from mitochondria involved in the expression of peptide transporter 1 and accelerate the uptake of 5-aminolevulinic acid, which is a precursor of protoporphyrin IX. We suggested mitochondrial reactive oxygen species also regulated the expression of heme carrier protein 1. In this study, we used a rat gastric mucosal cell line RGM1 and its cancer-like mutated cell line RGK1. We clarified the expression of heme carrier protein 1 increased in cancer cells and it decreased in manganese superoxide dismutase expressed cancer cells. In addition, the uptake level of hematoporphyrin and photodynamic therapeutic effect were also decreased in manganese superoxide dismutase expressed cancer cells in comparison with cancer cells. Thus, we concluded that mitochondrial reactive oxygen species regulated heme carrier protein 1 expression and photodynamic therapeutic effect.

Unique diagnostic and therapeutic roles of porphyrins and phthalocyanines in photodynamic therapy, imaging and theranostics

Porphyrinic molecules have a unique theranostic role in disease therapy; they have been used to image, detect and treat different forms of diseased tissue including age-related macular degeneration and a number of different cancer types. Current focus is on the clinical imaging of tumour tissue; targeted delivery of photosensitisers and the potential of photosensitisers in multimodal biomedical theranostic nanoplatforms. The roles of porphyrinic molecules in imaging and pdt, along with research into improving their selective uptake in diseased tissue and their utility in theranostic applications are highlighted in this Review.

Synergic effect of photodynamic therapy using talaporfin sodium with conventional anticancer chemotherapy for the treatment of bile duct carcinoma

BACKGROUND

Photodynamic therapy (PDT) is an effective laser treatment for locally treating advanced bile duct carcinoma (BDC). The study objective was to evaluate the synergic effect of PDT using a new photosensitizer, talaporfin sodium (Laserphyrin), in combination with conventional anticancer drug treatments.

METHODS

The range of the necrotic area, the percentage of apoptosis-positive cells, the vascular endothelial growth factor expression quantification, and the proliferating cell nuclear antigen-labeling index, as treatment effects, were examined in the BDC cell line (NOZ) in vitro and in vivo (4-wk-old male BALB/c mice).

RESULTS

Tumor viability was determined by an in vitro MTS assay. PDT with a single treatment of 5-fluorouracil, gemcitabine, oxaliplatin, and cis-diamminedichloroplatinum showed a significantly lower viability compared with the control or the PDT-alone group (P<0.05). Furthermore, administering PDT combined with two anticancer drugs showed a further decline in the tumor viability. A treatment of PDT combined with oxaliplatin and gemcitabine showed the least viability (P<0.05). Thus, this regimen was administered in the in vivo study. The tumor necrotic area, apoptosis positivity, and the vascular endothelial growth factor expression rate were higher in the PDT with anticancer drugs group compared with those of the other groups (P<0.05). The proliferating cell nuclear antigen-labeling index results in the PDT with the anticancer drugs group were significantly lower than those of the other groups (P<0.05).

CONCLUSIONS

A treatment of PDT combined with gemcitabine and oxaliplatin showed the best synergic effect for necrosis, apoptosis, and cytostatic alterations for the treatment of BDC.