Optimization and therapeutic effects of PDT mediated by ALA and MAL in the treatment of cutaneous malignant lesions: A comparative study

Topical 5-aminolevulinic acid (ALA)-photodynamic therapy (PDT) for lichen sclerosus of face: case report and literature review

Lichen sclerosus (LS) is a chronic inflammatory dermatosis typical of the genital region, with rare involvement of extragenital areas and particularly the face. LS therapeutic management is challenging, and common therapies including topical and systemic corticosteroids, topical calcineurin inhibitors, surgery are often ineffective. Herein, we present a case of LS occurred in a 36-year-old girl with facial involvement resistant to therapy with systemic corticosteroids and topical tacrolimus. Considering the involvement of a sensitive area, the young age of the patient, and the consistent clinical experience in using photodynamic therapy for the treatment of facial skin disease, we started a treatment with topical 5-aminolevulinic acid (ALA)-photodynamic therapy (PDT) with a dosage of 37 J/cm2 once a month. We compared our case with eight other facial LS patients from the literature and treated differently.

Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

Viral Nanoparticle System: An Effective Platform for Photodynamic Therapy

Photodynamic therapy (PDT) is a promising therapy due to its efficiency and accuracy. The photosensitizer is delivered to the target lesion and locally activated. Viral nanoparticles (VNPs) have been explored as delivery vehicles for PDT in recent years because of their favorable properties, including simple manufacture and good safety profile. They have great potential as drug delivery carriers in medicine. Here, we review the development of PDT photosensitizers and discuss applications of VNP-mediated photodynamic therapies and the performance of VNPs in the treatment of tumor cells and antimicrobial therapy. Furthermore, future perspectives are discussed for further developing novel viral nanocarriers or improving existing viral vectors.