Enhancing the Efficiency of Mild-Temperature Photothermal Therapy for Cancer Assisting with Various Strategies

Abstract

Conventional photothermal therapy (PTT) irradiates the tumor tissues by elevating the temperature above 48 °C to exert thermal ablation, killing tumor cells. However, thermal ablation during PTT harmfully damages the surrounding normal tissues, post-treatment inflammatory responses, rapid metastasis due to the short-term mass release of tumor-cellular contents, or other side effects. To circumvent this limitation, mild-temperature photothermal therapy (MTPTT) was introduced to replace PTT as it exerts its activity at a therapeutic temperature of 42–45 °C. However, the significantly low therapeutic effect comes due to the thermoresistance of cancer cells as MTPTT figures out some of the side-effects issues. Herein, our current review suggested the mechanism and various strategies for improving the efficacy of MTPTT. Especially, heat shock proteins (HSPs) are molecular chaperones overexpressed in tumor cells and implicated in several cellular heat shock responses. Therefore, we introduced some methods to inhibit activity, reduce expression levels, and hinder the function of HSPs during MTPTT treatment. Moreover, other strategies also were emphasized, including nucleus damage, energy inhibition, and autophagy mediation. In addition, some therapies, like radiotherapy, chemotherapy, photodynamic therapy, and immunotherapy, exhibited a significant synergistic effect to assist MTPTT. Our current review provides a basis for further studies and a new approach for the clinical application of MTPTT.

Novel Application of NIR-I-Absorbing Quinoidal Conjugated Polymer as a Photothermal Therapeutic Agent

“…While the temperature of the PBS + light group did not exceed 40 °C even at the highest temperature, the PQ NP + light group exhibited an average temperature of around 50 °C. It was reported that a temperature over 43–44 °C induced heat erythema and over 48 °C induced thermal ablation. , Therefore, the PQ NP is expected to effectively suppress the tumors. After PTT on the mouse skin, the tissues were stained with H&E and TUNEL assay to observe the tissue damages induced by PTT (Figure S17).…”

“…It was reported that a temperature over 43−44 °C induced heat erythema and over 48 °C induced thermal ablation. 57,58 Therefore, the PQ NP is expected to effectively suppress the tumors. After PTT on the mouse skin, the tissues were stained with H&E and TUNEL assay to observe the tissue damages induced by PTT (Figure S17).…”

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

“…PTT, like PDT, is a new and non-invasive therapy that uses the conversion of light energy into heat energy to increase the temperature and achieve therapeutic effects at the lesion site [ 105 ]. PTT can be directly mediated by MOFs with inherent photothermal properties without the introduction of an exogenous PTA by using several PTAs as ligands (e.g., IR825 and ferrocene (Fc)) [ 7 ].…”

A Photothermal Therapy Study Based on Electrospinning Nanofibers Blended and Coated with Polydopamine Nanoparticles

“…Within 5 min, the temperature of the tumor site reached 65.5 °C, which has the ability to rapidly thermally ablate tumor cells. [41,42] The photographs of the tumor bearing mice before and after photothermal therapies were showed in Figure 7c, and the body weight changes of nude mice during treatment are recorded in Figure 7d. There was no significant difference in the body weight of nude mice before and after treatment.…”