Theoretical aspects and modelling of cellular decision making, cell killing and information-processing in photodynamic therapy of cancer

In vitro phototherapeutic effects of indolenine-based mono- and dithiosquaraine cyanine dyes against Caco-2 and HepG2 human cancer cell lines

Photodynamic therapy is a noninvasive approach for the treatment of oncological and nononcological diseases which has attempted to address the shortcomings and disadvantages of conventional cancer therapies. Given the scarcity of photosensitizers that exhibit desirable characteristics for its potential application in this therapeutic strategy, the main aims of this work were the study of the photophysical and photochemical properties, and the in vitro photobiological activity of several squaraine cyanine dyes. Thus, herein, the synthesis of indolenine-based N-methyl and N-ethyl mono- and dithiosquaraine dyes, the study of their spectroscopical properties, aggregation behavior, photodegradation and singlet oxygen production ability, and the further application of the previously synthesized dyes in colorectal adenocarninoma and hepatocellular carcinoma cell lines to evaluate their phototherapeutic effects, are described. Thionation significantly favored the ability to singlet oxygen production, and moderate photostability was observed for squaraine and monothionated dyes. Squaraine and monothiosquaraine cyanine dyes showed high promise within the tested concentration range regarding their potential application as cancer photodynamic therapy photosensitizers. Squaraine dyes' monothionation resulted in the preparation of compounds with poor photocytotoxicity, which was an undesirable effect on their phototherapeutic application.

Illuminating the Numbers: Integrating Mathematical Models to Optimize Photomedicine Dosimetry and Combination Therapies

Cancer photomedicine offers unique mechanisms for inducing local tumor damage with the potential to stimulate local and systemic anti-tumor immunity. Optically-active nanomedicine offers these features as well as spatiotemporal control of tumor-focused drug release to realize synergistic combination therapies. Achieving quantitative dosimetry is a major challenge, and dosimetry is fundamental to photomedicine for personalizing and tailoring therapeutic regimens to specific patients and anatomical locations. The challenge of dosimetry is perhaps greater for photomedicine than many standard therapies given the complexity of light delivery and light-tissue interactions as well as the resulting photochemistry responsible for tumor damage and drug-release, in addition to the usual intricacies of therapeutic agent delivery. An emerging multidisciplinary approach in oncology utilizes mathematical and computational models to iteratively and quantitively analyze complex dosimetry, and biological response parameters. These models are parameterized by preclinical and clinical observations and then tested against previously unseen data. Such calibrated and validated models can be deployed to simulate treatment doses, protocols, and combinations that have not yet been experimentally or clinically evaluated and can provide testable optimal treatment outcomes in a practical workflow. Here, we foresee the utility of these computational approaches to guide adaptive therapy, and how mathematical models might be further developed and integrated as a novel methodology to guide precision photomedicine.

Apoptotic effects of Photofrin-Diomed 630-PDT on SHEEC human esophageal squamous cancer cells

Photodynamic therapy (PDT) using photofrin-II is a clinically effective treatment for both non-neoplastic and neoplastic diseases. Herein, we performed an in vitro experiment to study the anti-tumor effect and mechanisms of photofrin-II mediated PDT for esophageal squamous cell carcinoma (ESCC) cell line, SHEEC. In this study, human ESCC cell line SHEEC and parental normal cell line SHEE were used. The anti-tumor effect of PDT was determined by evaluating cell viability using CCK-8 assay, apoptosis and generation of reactive oxygen species (ROS). PDT induced significant apoptosis in SHEEC and SHEE cells in a time- and photofrin-II dose-dependent manner. Furthermore, PDT treatment induced significant death of SHEEC, instead of SHEE cells. The apoptotic outcome was accompanied by concurrent generation of ROS. In summary, PDT shed light on therapy of ESCC, functioning as a useful tool for ESCC clinical treatment, providing a better understanding of Photofrin-Diomed 630-PDT in SHEEC cells.