Hypoxia‐Responsive Gene Editing to Reduce Tumor Thermal Tolerance for Mild‐Photothermal Therapy

Enhanced mild-temperature photothermal therapy by pyroptosis-boosted ATP deprivation with biodegradable nanoformulation

BACKGROUND

Mild-temperature photothermal therapy (mild PTT) is a safe and promising tumor therapeutic modality by alleviating the damage of healthy tissues around the tumor due to high temperature. However, its therapeutic efficiency is easily restricted by heat shock proteins (HSPs). Thus, exploitation of innovative approaches of inhibiting HSPs to enhance mild PTT efficiency is crucial for the clinical application of PTT.

RESULTS

Herein, an innovative strategy is reported: pyroptosis-boosted mild PTT based on a Mn-gallate nanoformulation. The nanoformulation was constructed via the coordination of gallic acid (GA) and Mn²⁺. It shows an acid-activated degradation and releases the Mn²⁺ and GA for up-regulation of reactive oxygen species (ROS), mitochondrial dysfunction and pyroptosis, which can result in cellular ATP deprivation via both the inhibiton of ATP generation and incresed ATP efflux. The reduction of ATP and accumulation of ROS provide a powerful approach for inhibiting the expression of HSPs, which enables the nanoformulation-mediated mild PTT.

CONCLUSIONS

Our in-vitro and in-vivo results demonstrate that this strategy of pyroptosis-assited PTT can achieve efficient mild PTT efficiency for osteosarcoma therapy.

Cancer therapeutics based on diverse energy sources

Light-based phototherapy has been developed for cancer treatment owing to its non-invasiveness and spatiotemporal control. Despite the unique merits of phototherapy, one critical disadvantage of light is its limited penetration depth, which restricts its application in cancer treatment. Although many researchers have developed various strategies to deliver light into deep-seated tumors with two-photon and near-infrared light irradiation, phototherapy encounters the peculiar limitations of light. In addition, high oxygen dependency is another limitation of photodynamic therapy to treat hypoxic tumors. To overcome the drawbacks of conventional treatments, various energy sources have been developed for cancer treatment. Generally, most energy sources, such as ultrasound, chemiluminescence, radiation, microwave, electricity, and magnetic field, are relatively free from the restraint of penetration depth. Combining other strategies or therapies with other energy-source-based therapies improves the strength and compensates for the weakness. This tutorial review focuses on recent advances in the diverse energy sources utilized in cancer treatment and their future perspectives.

Chidamide stacked in magnetic polypyrrole nano-composites counter thermotolerance and metastasis for visualized cancer photothermal therapy

Photothermal therapy (PTT) has become one of the most promising therapies in cancer treatment as its noninvasiveness, high selectivity, and favorable compliance in clinic. However, tumor thermotolerance and distal metastasis reduce its efficacy, becoming the bottleneck of applying PTT in clinic. In this study, a chidamide-loaded magnetic polypyrrole nanocomposite (CMPP) has been fabricated as a visualized cancer photothermal agent (PTA) to counter tumor thermotolerance and metastasis. The efficacy of CMPP was characterized by in vitro and in vivo assays. As a result, this kind of magnetic polypyrrole nanocomposites were black spherical nanoparticles, possessing a favorable photothermal effect and the suitable particle size of 176.97 ± 1.45 nm with a chidamide loading rate of 12.92 ± 0.45%. Besides, comparing with PTT, CMPP exhibited significantly higher cytotoxicity and cellular apoptosis rate in two tumor cell lines (B16-F10 and HepG2). In vivo study, the mice showed obvious near-infrared (NIR) and magnetic resonance imaging (MRI) dual-modal imaging at tumor sites and sentinel lymph nodes (SLNs); on the other hand, magnetic targeting guided CMPP achieved a cure level on melanoma-bearing mice through preventing metastasis and thermotolerance. Overall, with high loading efficiency of chidamide and strong magnetic targeting to tumor sites and SLNs, CMPP could significantly raise efficiency of PTT by targeting tumor thermotolerance and metastasis, and this strategy may be exploited therapeutically to upgrade PTT with MPP as one of appropriate carriers for histone deacetylase inhibitors (HDACis).

A multifunctional α-Fe2O3@PEDOT core-shell nanoplatform for gene and photothermal combination anticancer therapy

Exploration of versatile nanoplatforms within one single nanostructure for multidisciplinary treatment modalities, especially achieving a synergistic therapeutic efficacy of combinational gene/photothermal cancer therapy is still a great challenge in biomedicine and nanotechnology. In this study, a unique photothermal nanocarrier has successfully been designed and developed for a combination of gene therapy (GT) and photothermal therapy (PTT) of cancer cells. Surface-engineered iron oxides (α-Fe₂O₃) nanoparticles (NPs) with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer coatings are synthesized using a one-pot in situ oxidative polymerization method. The results show that the as-prepared α-Fe₂O₃@PEDOT core-shell NPs with a uniform particle size exhibit positively charged surfaces, facilitating efficient siRNA Bcl-2 (B-cell lymphoma-2) uptake for delivery to breast cancer cells. More importantly, α-Fe₂O₃@PEDOT core-shell NPs not only display good biocompatibility and water dispersibility but also strong optical absorption enhancement in the Vis-NIR region as compared to α-Fe₂O₃ NPs. The obtained α-Fe₂O₃@PEDOT core-shell NPs show an efficient photothermal conversion efficacy (η = 54.3%) and photostability under NIR laser irradiation. As a result, both in vitro and in vivo biological studies on two types of breast cancer cells/tumors treated with α-Fe₂O₃@PEDOT-siRNA nanocomplexes demonstrate high cancer cell apoptosis and tumor inhibition induced by synergistic GT/PTT therapy under mild conditions compared to an individual GT or PTT alone. Taken together, this is the first example of the use of an α-Fe₂O₃@PEDOT core-shell nanoagent as a siRNA delivery nanocarrier for highly effective gene/photothermal combination anticancer therapy.