Induction of apoptosis in HPV16 E7 transfected human keratinocyte by ALA-mediated photodynamic therapy

5-aminolevulinic acid induced photodynamic reactions in diagnosis and therapy for female lower genital tract diseases

Since the patients suffering from female lower genital tract diseases are getting younger and younger and the human papilloma virus (HPV) infection is becoming more widespread, the novel non-invasive precise modalities of diagnosis and therapy are required to remain structures of the organ and tissue, and fertility as well, by which the less damage to normal tissue and fewer adverse effects are able to be achieved. In all nucleated mammalian cells, 5-Aminolevulinic acid (5-ALA) is an amino acid that occurs spontaneously, which further synthesizes in the heme biosynthetic pathway into protoporphyrin IX (PpIX) as a porphyrin precursor and photosensitizing agent. Exogenous 5-ALA avoids the rate-limiting step in the process, causing PpIX buildup in tumor tissues. This tumor-selective PpIX distribution after 5-ALA application has been used successfully for tumor photodynamic diagnosis (PDD) and photodynamic therapy (PDT). Several ALA-based drugs have been used for ALA-PDD and ALA-PDT in treating many (pre)cancerous diseases, including the female lower genital tract diseases, yet the ALA-induced fluorescent theranostics is needed to be explored further. In this paper, we are going to review the studies of the mechanisms and applications mainly on ALA-mediated photodynamic reactions and its effectiveness in treating female lower genital tract diseases.

Efficacy and Safety of 5-Aminolevulinic Acid Photodynamic Therapy for Treating Cervical and Vaginal Intraepithelial Neoplasia

Persistent HPV infections may cause cervical and vaginal intraepithelial neoplasia (CIN and VaIN). Traditional methods might destroy the structure and function of the cervix. 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a non-invasive targeted therapy. This study aims to evaluate the efficacy and safety of ALA-PDT for CIN and VaIN and the clearance of HPV. A retrospective study of 303 patients who confirmed CIN or VaIN and received ALA-PDT was conducted. All the patients were followed up at six and twelve months after treatment and then annually thereafter. The effect was evaluated through HPV genotyping, a cytology test, and colposcopy-directed biopsy if necessary. After ALA-PDT, the remission rates for CIN 2, CIN 3, VaIN 2, and VaIN 3 were 90.6%, 88.5%, 87.3%, and 77.8%. For CIN 1, the remission rate at the six-month follow-up was 93.1%. The total HPV clearance rates were 72.5% at the six-month follow-up and 85.7% at the 12-month follow-up. The most common adverse event was vaginal discharge. No severe adverse effect was observed. ALA-PDT is an effective and safe treatment for all grades of CIN and VaIN and is helpful in clearing HPV with minimal side effects. This treatment may not influence fertility and delivery.

A novel PDT: 5-aminolevulinic acid combined 450 nm blue laser photodynamic therapy significantly promotes cell death of HR-HPV infected cells

Human papillomavirus (HPV) infection and related diseases are clinical challenges. The efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) using red laser (630 ± 5 nm) is remarkable and safe. In this study, we aim to investigate the efficacy of ALA-450 nm PDT comparing with ALA-635 nm PDT. We detected cell proliferation and cell apoptosis through MTT assay and flow cytometry assay respectively. Flow cytometry assay determined the intracellular reactive oxygen species (ROS) generation. Western blotting analysis investigated the protein expression. In vivo, immunohistochemical staining assay and TUNEL assay were performer to detect cell apoptosis. ALA-450 nm PDT inhibited the proliferation of End1 and HeLa cells, promoted cell apoptosis more effectively than ALA-635 nm PDT, and induced cell death probably through increasing the intracellular ROS generation and caspase-dependent apoptosis pathway. In vivo, ALA-450 nm PDT significantly inhibited tumour growth and activated cell apoptosis. The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibiting the proliferation of End1 and HeLa cells and inducing cell apoptosis. The ALA-450 nm PDT might be a promising therapeutic strategy for eradicating the HR-HPV infected cells and promoting the integration of diagnosis and treatment of HR-HPV related diseases.HighlightsWe combined 5-aminolevulinic acid with 450 nm blue laser using as a novel type of photodynamic therapy.The ALA-450 nm PDT had an advantage over ALA-635 nm PDT on inhibition of the proliferation of End1 and HeLa cells and inducing cell apoptosis in vitro and in vivo.The ALA-450 nm PDT may provide a novel alternative therapeutic option in patients with persistent HPV infection and promote the integration of diagnosis and treatment.

5-Aminolevulinic Acid as a Theranostic Agent for Tumor Fluorescence Imaging and Photodynamic Therapy

5-Aminolevulinic acid (ALA) is a naturally occurring amino acid synthesized in all nucleated mammalian cells. As a porphyrin precursor, ALA is metabolized in the heme biosynthetic pathway to produce protoporphyrin IX (PpIX), a fluorophore and photosensitizing agent. ALA administered exogenously bypasses the rate-limit step in the pathway, resulting in PpIX accumulation in tumor tissues. Such tumor-selective PpIX disposition following ALA administration has been exploited for tumor fluorescence diagnosis and photodynamic therapy (PDT) with much success. Five ALA-based drugs have now received worldwide approval and are being used for managing very common human (pre)cancerous diseases such as actinic keratosis and basal cell carcinoma or guiding the surgery of bladder cancer and high-grade gliomas, making it the most successful drug discovery and development endeavor in PDT and photodiagnosis. The potential of ALA-induced PpIX as a fluorescent theranostic agent is, however, yet to be fully fulfilled. In this review, we would like to describe the heme biosynthesis pathway in which PpIX is produced from ALA and its derivatives, summarize current clinical applications of ALA-based drugs, and discuss strategies for enhancing ALA-induced PpIX fluorescence and PDT response. Our goal is two-fold: to highlight the successes of ALA-based drugs in clinical practice, and to stimulate the multidisciplinary collaboration that has brought the current success and will continue to usher in more landmark advances.

Photodynamic effect of protoporphyrin IX in gliosarcoma 9l/lacZ cell line

Photodynamic Therapy (PDT) is an oncologic treatment, producing reactive oxygen species (ROS) to induce the death of cancer cells. This study aimed to evaluate the action of PDT on gliosarcoma cells, using protoporphyrin IX as PS by incubation with the precursor aminolevulinic acid (ALA). An LED device was used with a light dose of 10 J/cm². The success of the therapy proved to be dependent on the concentration of ALA, and an incubation time of 4 h required for an effective response. Cell death was prevalent due to necrosis when assessed 18 h post-PDT. ALA proved to be an option to PDT in cells of the 9 L/lacZ, with the protocol tested.

The effect of 5-Aminolaevulinic Acid Photodynamic Therapy versus CO2 laser in the Treatment of Cervical Low-grade Squamous Intraepithelial Lesions with High-Risk HPV Infection: A non-randomized, controlled pilot study

BACKGROUND

There are insufficient studies comparing the efficacy of 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) against CO₂ laser therapy in the treatment of cervical low-grade squamous intraepithelial lesion (LSIL) with high-risk human papillomavirus (HR-HPV), especially for long-term efficacy.

METHODS

Patients with cervical LSIL and HR-HPV infection were divided into two treatment groups based on their own choice. All patients had a follow-up test including HPV testing, cytology and colposcopy at 4-6 months and 12 months after the treatment.

RESULTS

(1) Among 277 patients, 176 patients received 5-ALA PDT and 101 patients received CO₂ laser therapy. (2) 4-6 months after treatment, there was no significant difference between two groups in the complete remission (CR) rates of cervical LSIL and the clearance rate of HR-HPV infection. (3) 12 months after treatment, compared with the CO₂ laser group, the CR rates of cervical LSIL in the 5-ALA PDT group was significantly higher than the CO₂ laser group. There was no statistical difference in the clearance rate of HR-HPV infection between the two groups. (4) 12 months after treatment, the recurrence rate of cervical lesions and the reinfection rate of HR-HPV infection in 5-ALA PDT group were significantly lower than those in CO₂ laser group.

CONCLUSION

The effect of 5-ALA PDT is similar to CO₂ laser at 4-6 months. The long-term efficacy of 5-ALA PDT appears better than CO₂ laser. As a non-invasive treatment, 5-ALA PDT is a highly effective therapeutic procedure for cervical LSIL with HR-HPV infection.

Multi-enzymatic recycling of ATP and NADPH for the synthesis of 5-aminolevulinic acid using a semipermeable reaction system

5-Aminolevulinic acid (ALA) is an important cellular metabolic intermediate that has broad agricultural and medical applications. Previously, attempts have been made to synthesize ALA by multiple enzymes in cell free systems. Here we report the development of a semi-permeable system for ALA production using stable enzymes. Glucose, sodium polyphosphate, ATP, tRNA, glutamate and NADPH were used as substrates for ALA synthesis by a total of nine enzymes: adenylate kinase, polyphosphate kinase, glucose-6-phosphate dehydrogenase, phosphogluconolactonase, 6-phosphogluconate dehydrogenase, glutamyl-tRNA synthetase and glutamate-1-semialdehyde aminotransferase from E. coli, hexokinase from yeast, as well as glutamyl-tRNA reductase and its stimulator protein glutamyl-tRNA reductase binding protein (GBP) from Arabidopsis in a semi-permeable system. After reaction for 48 h, the glutamate conversion reached about 95%. This semi-permeable system facilitated the reuse of enzymes, and was helpful for the separation and purification of the product. The ALA production could be further improved by process optimization and enzyme engineering.Abbreviations: PPK: polyphosphate kinase; ADK: adenylate kinase; ALA: 5-Aminolevulinic acid; HK: hexokinase; ZWF: glucose-6-phosphatedehydrogenase; PGL: phosphogluconolactonase; GND: 6-phosphogluconate dehydrogenase; GTS: glutamyl-tRNA synthetase; GTR: glutamyl-tRNA reductase; GBP: GTR binding protein; GSAAT: glutamate-1-semialdehyde aminotransferase.

Human papillomavirus DNA detection-guided ALA-photodynamic therapy for anogenital condyloma acuminata: A report of two cases

5-aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) is a highly effective, safe, and promising treatment for human papillomavirus (HPV)-induced anogenital condyloma acuminata (CA). Specific HPV subtypes are responsible for the pathogenesis of CA and dynamic changes in viral loads may reflect the efficiency of PDT. Here we present two cases of anogenital CA successfully treated by ALA-PDT under the guidance of HPV DNA detection including genotype identification and viral load measurement, which provided clues for unexpected intra-anal infection. Both of these male patients were free of detectable HPV at the end of the treatment and no recurrence was observed after 1 year. We conclude that the HPV DNA detection can accurately guide ALA-PDT, indicate unnoticed lesions, as well as improve and evaluate the efficiency.