Epigenetically Enhanced Photodynamic Therapy (ePDT) is Superior to Conventional Photodynamic Therapy for Inducing Apoptosis in Cutaneous T-Cell Lymphoma

Pharmaceutical Approach to Develop Novel Photosensitizer Nanoformulation: An Example of Design and Characterization Rationale of Chlorophyll α Derivative

In this study, we described physico-chemical properties of novel nanoformulation of photosensitizer-pyropheophorbide α 17-diethylene glycol ester (XL) (chlorophyll α derivative), revealing insights into antitumor activity and maintaining quality, meeting the pharmaceutical approach of new nanoformulation design. Our formulation, based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles, increased XL solubility and selective tumor-targeted accumulation. In our research, we revealed, for the first time, that XL binding to polyvinyl alcohol (PVA) enhances XL photophysical activity, providing the rationale for PVA application as a stabilizer for nanoformulations. Results of FTIR, DSC, and XRD revealed the physical interactions between XL and excipients, including PVA, indicating that the encapsulation maintained XL binding to PVA. The encapsulated XL exhibited higher photophysical activity compared to non-encapsulated substance, which can be attributed to the influence of residual PVA. Gamma-irradiation led to degradation of XL; however, successful sterilization of the samples was achieved through the filtration. Importantly, the encapsulated and sterilized XL retained cytotoxicity against both 2D and 3D tumor cell models, demonstrating the potential of the formulated NP-XL for photodynamic therapy applications, but lacked the ability to reactivate epigenetically silenced genes. These findings provide valuable insights into the design and characterization of PLGA-based nanoparticles for the encapsulation of photosensitizers.

Current Strategies in Photodynamic Therapy (PDT) and Photodynamic Diagnostics (PDD) and the Future Potential of Nanotechnology in Cancer Treatment

Photodynamic diagnostics (PDD) and photodynamic therapy (PDT) are well-established medical technologies used for the diagnosis and treatment of malignant neoplasms. They rely on the use of photosensitizers, light and oxygen to visualize or eliminate cancer cells. This review demonstrates the recent advancements in these modalities with the use of nanotechnology, including quantum dots as innovative photosensitizers or energy donors, liposomes and micelles. Additionally, this literature review explores the combination of PDT with radiotherapy, chemotherapy, immunotherapy, and surgery for treating various neoplasms. The article also focuses on the latest achievements in PDD and PDT enhancements, which seem to be very promising in the field of oncology.

An Update on Recent Advances of Photodynamic Therapy for Primary Cutaneous Lymphomas

Primary cutaneous lymphomas are rare non-Hodgkin lymphomas consisting of heterogeneous disease entities. Photodynamic therapy (PDT) utilizing photosensitizers irradiated with a specific wavelength of light in the presence of oxygen exerts promising anti-tumor effects on non-melanoma skin cancer, yet its application in primary cutaneous lymphomas remains less recognized. Despite many in vitro data showing PDT could effectively kill lymphoma cells, clinical evidence of PDT against primary cutaneous lymphomas is limited. Recently, a phase 3 "FLASH" randomized clinical trial demonstrated the efficacy of topical hypericin PDT for early-stage cutaneous T-cell lymphoma. An update on recent advances of photodynamic therapy in primary cutaneous lymphomas is provided.

Photodynamic therapy regulates fate of cancer stem cells through reactive oxygen species

Photodynamic therapy (PDT) is an effective and promising cancer treatment. PDT directly generates reactive oxygen species (ROS) through photochemical reactions. This oxygen-dependent exogenous ROS has anti-cancer stem cell (CSC) effect. In addition, PDT may also increase ROS production by altering metabolism, endoplasmic reticulum stress, or potential of mitochondrial membrane. It is known that the half-life of ROS in PDT is short, with high reactivity and limited diffusion distance. Therefore, the main targeting position of PDT is often the subcellular localization of photosensitizers, which is helpful for us to explain how PDT affects CSC characteristics, including differentiation, self-renewal, apoptosis, autophagy, and immunogenicity. Broadly speaking, excess ROS will damage the redox system and cause oxidative damage to molecules such as DNA, change mitochondrial permeability, activate unfolded protein response, autophagy, and CSC resting state. Therefore, understanding the molecular mechanism by which ROS affect CSCs is beneficial to improve the efficiency of PDT and prevent tumor recurrence and metastasis. In this article, we review the effects of two types of photochemical reactions on PDT, the metabolic processes, and the biological effects of ROS in different subcellular locations on CSCs.

Cutaneous T Cell Lymphoma: A Difficult Diagnosis Demystified

Cutaneous T cell lymphoma (CTCL) represents a heterogeneous group of extranodal non-Hodgkin lymphomas in which monoclonal T lymphocytes infiltrate the skin. The mechanism of CTCL development is not fully understood, but likely involves dysregulation of various genes and signaling pathways. A variety of treatment modalities are available, and although they can induce remission in most patients, the disease may recur after treatment cessation. Owing to relatively low incidence and significant chronicity of disease, and the high morbidity of some therapeutic regimens, further clinical trials are warranted to better define the ideal treatment option for each subtype of CTCL.

Preclinical Studies Support Combined Inhibition of BET Family Proteins and Histone Deacetylases as Epigenetic Therapy for Cutaneous T-Cell Lymphoma

Advanced-stage cutaneous T-cell lymphoma (CTCL) is usually a fatal malignancy despite optimal use of currently available treatments. In this preclinical study of novel CTCL therapy, we performed in vitro and ex vivo experiments to determine the efficacy of combination treatment with a panel of BET bromodomain inhibitors (BETi) (JQ1, OTX015, CPI-0610, I-BET762) and HDAC inhibitors (HDACi) (SAHA/Vorinostat, Romidepsin). BETi/HDACi combinations were synergistic (combination index <1) against cell viability and induced G0/G1 cell cycle arrest. Apoptosis was uniformly enhanced. From a mechanistic standpoint, proliferative drivers c-Myc, Cyclin D1, NFkB, and IL-15Rα were reduced. Inhibitory CDKN1A was increased. CDKN1B, IL-7R, IL-17Rα, STAT3, and STAT5 alterations varied. There were significant increases in extrinsic apoptotic pathway death receptors and ligands (FasL, DR4, DR5, TRAIL, and TNFR1). At clinically tolerable levels of single agents, Romidepsin (1 nM) + OTX015 (125 nM) induced the greatest apoptosis (60%_80%) at 96 hours. Ex vivo studies of leukemic CTCL cells obtained from patients with Sezary syndrome also showed higher levels of apoptosis (about 60%-90%) in response to combination treatments relative to single agents. In contrast, combination treatment of normal CD4+ T cells induced only minimal apoptosis (<10%). Our findings show that the mechanism of action of BETi/HDACi therapy in CTCL involves induction of both cell cycle arrest and apoptosis with reduced proliferative drivers and enhanced expression of apoptotic extrinsic pathway death receptors and ligands. Relative to single agents, the superior anti-CTCL effects of BETi/HDACi combinations in vitro and ex vivo provide a rationale for clinical trials exploring their efficacy as therapy for CTCL.

Cutaneous T-cell lymphomas: modern data of pathogenesis, clinics and therapy

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin’s lymphomas that are characterized by skin infiltration with malignant monoclonal T lymphocytes. More common in adults aged 55 to 60 years, the annual incidence is about 0.5 per 100 000 people. Mycosis fungoides, Sézary syndrome and CD30+ lymphoproliferative diseases are the main subtypes of CTCL. To date, CTCL have a complex concept of etiopathogenesis, diagnosis, therapy and prognosis. The article presented summary data on these issues.

Epigenetically Enhanced PDT Induces Significantly Higher Levels of Multiple Extrinsic Pathway Apoptotic Factors than Standard PDT, Resulting in Greater Extrinsic and Overall Apoptosis of Cutaneous T-cell Lymphoma

Aminolevulinate-based photodynamic therapy (ALA-PDT) selectively eliminates diseased tissues primarily through the induction of intrinsic apoptotic pathway. ALA-PDT is a first-line therapy for actinic keratosis, however, it is less effective for cutaneous T-cell lymphoma (CTCL). We have previously demonstrated that the resistance of CTCL to apoptosis correlates with decreased expression of death receptors such as FAS, and that methotrexate functions as an epigenetic regulator that reestablishes the susceptibility of CTCL to extrinsic pathway apoptosis. We showed previously that MTX augments the effectiveness of PDT by sensitizing cells to apoptosis by induction of apoptotic factors, a process we call "epigenetically enhanced" PDT (ePDT). Here, in CTCL cell lines, leukemic CTCL cells, and normal blood T cells, we analyzed multiple components of the FAS, TRAIL, and TNF families using multispectral imaging of immunostained cytopreparations, a quantitative technique with five-fold greater sensitivity than standard immunocytology. ePDT induced significantly greater FAS, FASL, TRAIL-R1 & -R2, and TNFα levels than standard PDT. This correlated with significantly greater induction of extrinsic pathway apoptosis and/or overall apoptosis in all CTCL samples. There was no appreciable effect on normal T cells. These data set the stage for clinical trials of ePDT as a novel localized treatment of CTCL.

An overview of cutaneous T cell lymphomas

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of extranodal non-Hodgkin’s lymphomas that are characterized by a cutaneous infiltration of malignant monoclonal T lymphocytes. They typically afflict adults with a median age of 55 to 60 years, and the annual incidence is about 0.5 per 100,000. Mycosis fungoides, Sézary syndrome, and primary cutaneous peripheral T cell lymphomas not otherwise specified are the most important subtypes of CTCL. CTCL is a complicated concept in terms of etiopathogenesis, diagnosis, therapy, and prognosis. Herein, we summarize advances which have been achieved in these fields.