Polyphosphoester-Based Nanocarrier for Combined Radio-Photothermal Therapy of Breast Cancer

Breakthrough of Hypoxia Limitation by Tumor-Targeting Photothermal Therapy-Enhanced Radiation Therapy

Purpose

To address the problem of suboptimal reactive oxygen species (ROS) production in Radiation therapy (RT) which was resulted from exacerbated tumor hypoxia and the heterogeneous distribution of radiation sensitizers.

Materials and Methods

In this work, a novel nanomedicine, designated as PLGA@IR780-Bi-DTPA (PIBD), was engineered by loading the radiation sensitizer Bi-DTPA and the photothermal agent IR780 onto poly(lactic-co-glycolic acid) (PLGA). This design leverages the tumor-targeting ability of IR780 to ensure selective accumulation of the nanoparticles in tumor cells, particularly within the mitochondria. The effect of the photothermal therapy-enhanced radiation therapy was also examined to assess the alleviation of hypoxia and the enhancement of radiation sensitivity.

Results

The PIBD nanoparticles exhibited strong capacity in mitochondrial targeting and selective tumor accumulation. Upon activation by 808 nm laser irradiation, the nanoparticles effectively alleviated local hypoxia by photothermal effect enhanced blood supplying to improve oxygen content, thereby enhancing the ROS production for effective RT. Comparative studies revealed that PIBD-induced RT significantly outperformed conventional RT in treating hypoxic tumors.

Conclusion

This design of tumor-targeting photothermal therapy-enhanced radiation therapy nanomedicine would advance the development of targeted drug delivery system for effective RT regardless of hypoxic microenvironment.

Synergistic effect of mesoporous silica nanocarrier-assisted photodynamic therapy and anticancer agent activity on lung cancer cells

Investigating combined treatment methodologies is crucial for addressing the complex nature of cancer. As an emerging strategy, nano-biotechnology encourages the design of unique nanocarriers possessing simultaneous therapeutic application properties. This study aims to explore the combined effects of photodynamic and anticancer treatments using a multifunctional nanocarrier system co-administering the photosensitizer IR780 and the anticancer agent curcumin (Cur) on lung cancer cells. Nanocarriers were prepared by encapsulation IR780 and Cur inside polyethylene glycol-capped mesoporous silica nanoparticles (Cur&IR780@MSN). Various concentrations of nanocarriers were evaluated on A549 cells following 5 min NIR laser light (continuous wave, 785 nm, 500 mW/cm2) irradiation. The internalization of nanocarriers was observed through the fluorescence of Cur. Changes in cell viability were determined using the MTT assay and AO/PI staining. A scratch assay analysis was also performed to examine the impact of combined treatments on cell migration. Characterization of the nanocarriers revealed adequate hydrophobic drug loading, temperature-inhibited feature, enhanced reactive oxygen species generation, a pH-dependent curcumin release profile, and high biocompatibility. Cur&IR780@MSN, which enabled the observation of synergistic treatment efficacy, successfully reduced cell viability by up to 78%. In contrast, monotherapies with curcumin-loaded nanocarriers (Cur@MSN) and IR780-loaded nanocarriers (IR780@MSN) resulted in a 38% and 56% decrease in cell viability, respectively. The constructed Cur&IR780@MSN nanocarrier has demonstrated remarkable performance in the application of combination therapies for lung cancer cells. These nanocarriers have the potential to inspire future studies in tumor treatment methods.

Synergetic Thermal Therapy for Cancer: State-of-the-Art and the Future

As a safe and minimal-invasive modality, thermal therapy has become an effective treatment in cancer treatment. Other than killing the tumor cells or destroying the tumor entirely, the thermal modality results in profound molecular, cellular and biological effects on both the targeted tissue, surrounding environments, and even the whole body, which has triggered the combination of the thermal therapy with other traditional therapies as chemotherapy and radiation therapy or new therapies like immunotherapy, gene therapy, etc. The combined treatments have shown encouraging therapeutic effects both in research and clinic. In this review, we have summarized the outcomes of the existing synergistic therapies, the underlying mechanisms that lead to these improvements, and the latest research in the past five years. Limitations and future directions of synergistic thermal therapy are also discussed.

Review of a new bone tumor therapy strategy based on bifunctional biomaterials

Bone tumors, especially those in osteosarcoma, usually occur in adolescents. The standard clinical treatment includes chemotherapy, surgical therapy, and radiation therapy. Unfortunately, surgical resection often fails to completely remove the tumor, which is the main cause of postoperative recurrence and metastasis, resulting in a high mortality rate. Moreover, bone tumors often invade large areas of bone, which cannot repair itself, and causes a serious effect on the quality of life of patients. Thus, bone tumor therapy and bone regeneration are challenging in the clinic. Herein, this review presents the recent developments in bifunctional biomaterials to achieve a new strategy for bone tumor therapy. The selected bifunctional materials include 3D-printed scaffolds, nano/microparticle-containing scaffolds, hydrogels, and bone-targeting nanomaterials. Numerous related studies on bifunctional biomaterials combining tumor photothermal therapy with enhanced bone regeneration were reviewed. Finally, a perspective on the future development of biomaterials for tumor therapy and bone tissue engineering is discussed. This review will provide a useful reference for bone tumor-related disease and the field of complex diseases to combine tumor therapy and tissue engineering.

Cyclic ethylene phosphates with (CH2)nCOOR and CH2CONMe2 substituents: synthesis and mechanistic insights of diverse reactivity in aryloxy-Mg complex-catalyzed (co)polymerization

Herein we present a comparative study of the reactivity of ethylene phosphates with –O(CH2)nCOOMe (n = 1–3, 5), –CH2COOtBu, –OCHMeCOOMe, and –OCH2CONMe2 substituents in BHT-Mg catalyzed ROP.

Highly-controllable drug release from core cross-linked singlet oxygen-responsive nanoparticles for cancer therapy

Highly-controllable release consisting of preventing unnecessary drug leakage at physiologically normal tissues and triggering sufficient drug release at tumor sites is the main aim of nanoparticle-based tumor therapy. Developing drug-conjugation strategies with covalent bonds in response to a characteristic stimulus, such as reactive oxygen species (ROS) generated by photodynamic therapy (PDT) has attracted much attention. ROS can not only cause cytotoxicity, but also trigger the cleavage of ROS-responsive linkers. Therefore, it is feasible to design a new model of controlled drug release via the breakage of ROS-responsive linkers and degradation of nanoparticles. The self-supply of the stimulus and highly-controllable drug release can be achieved by encapsulation of photosensitizer (PS) and chemotherapeutic drugs simultaneously without any support of tumor endogenous stimuli. Therefore, we used thioketal (TK) linkers as the responsive linkers due to their reaction with singlet oxygen (¹O₂, SO), a type of ROS. They were conjugated to the side groups of polyphosphoesters (PPE) via click chemistry to acquire the core cross-linked SO-responsive PPE nanoparticles poly(thioketal phosphoesters) (TK-PPE). TK-PPE coated with the photosensitizer chlorin e6 (Ce6) and chemotherapeutic drug doxorubicin (DOX) simultaneously were prepared and named as TK-PPE_Ce6&DOX. TK-PPE_Ce6&DOX kept stable due to the high stability of the TK-linkers in the normal physiological environment. With self-production of SO as the stimulating factor from the encapsulated Ce6, highly-controlled drug release was achieved. After incubation of tumor cells, 660 nm laser irradiation induced SO generation, resulting in the cleavage of TK-linkers and boosted-release of DOX. Highly-controllable drug release of TK-PPE_Ce6&DOX through self-production of stimulus increased antitumor efficacy, offering a promising avenue for clinical on-demand chemotherapy.

Core cross-linked singlet oxygen-responsive nanoparticle TK-PPE_Ce6&DOX could achieve highly-controllable drug release through self-production of SO as the stimulus to increase antitumor efficacy for cancer therapy.