Phototoxicity in a laryngeal cancer cell line enhanced by a targeting amphiphilic chlorin photosensitizer

Combination of carboplatin and photodynamic therapy with 9-hydroxypheophorbide ɑ enhances mitochondrial and endoplasmic reticulum apoptotic effect in AMC-HN-3 laryngeal cancer cells

BACKGROUND

Previously, we demonstrated that the combined mode of carboplatin (CBDCA) and photodynamic therapy (PDT) based on 9-hydroxypheophorbide (9-HPbD) enhanced cytotoxicity and apoptosis on AMC-HN-3 laryngeal cancer cells. The present study aimed to investigate anti-tumor effect of the combined therapy in vivo and the potential role of reactive oxygen species (ROS) in these enhanced apoptotic pathways initiated by the combined therapy in AMC-HN-3 cells.

METHODS

Mitochondrial membrane potential (MMP) and intracellular Ca²⁺were detected under confocal microscopy. Various apoptotic pathways were detected by western blots. In vivo study with the combined regimen was also performed on AMC-HN-3 cells-xenograft nude mice.

RESULTS

In vitro study showed that the combined treatment could decrease the level of MMP, increase intracellular Ca²⁺ and AIF translocation, and activate the expression of caspase-12. Mechanismly, the augmented apoptotic effect was mediated by ROS. The synergistic antitumor effect was also observed in vivo.

CONCLUSIONS

The mechanism of CBDCA and 9-HPbD-PDT combination involves ROS-mediated mitochondrial and endoplasmic reticulum apoptosis pathways. This combination may be a promising treatment strategy for laryngeal cancer.

Photodynamic therapy with a new bacteriochlorin derivative: Characterization and in vitro studies

Photodynamic therapy presents a therapeutic choice that can be utilized to treat diverse neoplasms. In this technique, the critical element is a photosensitive molecule that absorbs light energy and transfers it to molecular oxygen or biological molecules to form reactive oxygen species, thus inducing irreversible damage to target cells and ultimately leading to cell death. Bacteriochlorin derivatives are employed as photosensitizers (PSs), possessing light-absorbing capacity in the near-infrared region. The objective of this study was to prepare a semi-synthetic bacteriochlorin from Rhodopseudomonas faecalis and adding Trizma® to improve solubility. Cell viability tests, flow cytometry (apoptotic and necrotic cells were identified by Annexin V and propidium iodide), and confocal microscopy were used to evaluate the photoactivity of bacteriochlorin-Trizma (Bchl-T) in fibroblast (HFF-1-control cells) and breast cancer (MCF-7 cells-target cells) cells. At concentrations above 0.5 μM, Bchl-T demonstrated 80 % cell death, presenting the highest PS interaction (via fluorescence microscopy) with lysosomes, mitochondria, and the endoplasmic reticulum; the cell death type was revealed as apoptosis (via cytometry). Our findings indicated the suitability of Bchl-T for future application in photodynamic therapy against cancer cells by inducing apoptosis.