Aggregate formation and radiolytic degradation of amphiphilic DNA block copolymer possessing disulfide bond

Harnessing External Irradiation for Precise Activation of Metal-Based Agents in Cancer Therapy

Cancer is a significant global health issue. Platinum-based chemotherapy drugs, including cisplatin, are crucial in clinical anti-cancer treatment. However, these drugs have limitations such as drug resistance, non-specific distribution, and irreversible toxic and side effects. In recent years, the development of metal-based agents has led to the discovery of other anti-cancer effects beyond chemotherapy. Precise spatiotemporal controlled external irradiation can activate metal-based agents at specific sites and play a different role from traditional chemotherapy. These strategies can not only enhance the anti-cancer efficiency, but also show fewer side effects and non-cross-drug resistance, which are ideal approaches to solve the problems caused by traditional platinum-based chemotherapy drugs. In this review, we focus on various metal-based agent-mediated cancer therapies that are activated by three types of external irradiation: near-infrared (NIR) light, ultrasound (US), and X-ray, and give some prospects. We hope that this review will promote the generation of new kinds of metal-based anti-cancer agents.

Recent Progress and Trends in X-ray-Induced Photodynamic Therapy with Low Radiation Doses

The prominence of photodynamic therapy (PDT) in treating superficial skin cancer inspires innovative solutions for its congenitally deficient shadow penetration of the visible-light excitation. X-ray-induced photodynamic therapy (X-PDT) has been proven to be a successful technique in reforming the conventional PDT for deep-seated tumors by creatively utilizing penetrating X-rays as external excitation sources and has witnessed rapid developments over the past several years. Beyond the proof-of-concept demonstration, recent advances in X-PDT have exhibited a trend of minimizing X-ray radiation doses to quite low values. As such, scintillating materials used to bridge X-rays and photosensitizers play a significant role, as do diverse well-designed irradiation modes and smart strategies for improving the tumor microenvironment. Here in this review, we provide a comprehensive summary of recent achievements in X-PDT and highlight trending efforts using low doses of X-ray radiation. We first describe the concept of X-PDT and its relationships with radiodynamic therapy and radiotherapy and then dissect the mechanism of X-ray absorption and conversion by scintillating materials, reactive oxygen species evaluation for X-PDT, and radiation side effects and clinical concerns on X-ray radiation. Finally, we discuss a detailed overview of recent progress regarding low-dose X-PDT and present perspectives on possible clinical translation. It is expected that the pursuit of low-dose X-PDT will facilitate significant breakthroughs, both fundamentally and clinically, for effective deep-seated cancer treatment in the near future.

Emerging strategies based on nanomaterials for ionizing radiation-optimized drug treatment of cancer

Drug-radiotherapy is a common and effective combinational treatment for cancer. This study aimed to explore the ionizing radiation-optimized drug treatment based on nanomaterials so as to improve the synergistic efficacy of drug-radiotherapy against cancer and limit the adverse effect on healthy organs. In this review, these emerging strategies were divided into four parts. First, the delivery of the drug-loaded nanoparticles was optimized owing to the strengthened passive targeting process, active targeting process, and cell targeting process of nanoparticles after ionizing radiation exposure. Second, nanomaterials were designed to respond to the ionizing radiation, thus leading to the release of the loading drugs controllably. Third, radiation-activated pro-drugs were loaded onto nanoparticles for radiation-triggered drug therapy. In particular, nontoxic nanoparticles with radiosensitization capability and innocuous radio-dynamic contrast agents can be considered as radiation-activated drugs, which were discussed in this review. Fourth, according to the various synergetic mechanisms, radiotherapy could improve the drug response of cancer, obtaining optimized drug-radiotherapy. Finally, relative suggestions were provided to further optimize these aforementioned strategies. Therefore, a novel topic was selected and the emerging strategies in this region were discussed, aiming to stimulate the inspiration for the development of ionizing radiation-optimized drug treatment based on nanomaterials.

Modulation of cell membrane functionalization with aggregates of oligodeoxynucleotides containing alkyl chain-modified uridines

In this study, we prepared oligodeoxynucleotides (ODNs) containing the uridine base modified by an alkyl chain at the 5-position (AU) and characterized their aggregate formation, localization, and functions in cells. These experiments revealed that aggregates of these ODNs were readily transported into cells, but their localization was dependent upon the number of hydrophobic units. ODNs with one modified AU were transported in the cytosol, while ODNs with multiple AU modifications resulted in their accumulation at the cell membrane. We also examined the ability of the AU-modified ODNs to capture small molecules at the cell membrane and their cellular uptake. We positioned a thioflavin-T (ThT)-binding aptamer on the cell membrane by means of hybridization with ODNs with three AUs at the strand end. Treatment with ThT resulted in its efficient uptake into cells, due to the capture of the ThT by the aptamers on the cell membrane. Thus, we demonstrated the functionalization of cell membranes with modified ODNs and the efficient delivery of small molecules into the cells.

Overcoming the Achilles' heel of photodynamic therapy

This review summarizes the latest progress in deep photodynamic therapy (PDT), which overcomes the Achilles' heel of PDT.

Chemical ligation of oligodeoxynucleotides by X-irradiation and its application to regulation of G-quadruplex formation

We demonstrated radiolytic ligation of oligodeoxynucleotides (ODNs) possessing disulfide bond and its application to regulation of DNA quadruplex formation. G-rich hexamer ODNs had poor ability to form quadruplex, while X-irradiation of the ODNs induced interstrand exchange reaction at disulfide bond to form ligated 12 mer ODNs, leading to the ready formation of quadruplex due to the entropic effect. Since complexation of the ligated ODNs with hemin in the presence of K(+) showed strong soret band absorption and also catalyzed the H(2)O(2)-mediated oxidation of luminol, it appears that the quadruplex formed from ligated ODNs showed a function similar to native DNA quadruplex.