A coassembled peptide hydrogel boosts the radiosensitization of cisplatin

Phe-Phe-Based Macroscopic Supramolecular Hydrogel Construction Strategies and Biomedical Applications

Since the phenylalanine (Phe) dipeptide moiety is referred to as an essential structure for building amyloid-β peptide from Alzheimer's disease, its wonderful assembly ability to form nanofibers has been extensively studied. Cross-linked Phe-Phe-based peptide nanofibers can construct networks, thus encapsulating the drugs to form supramolecular hydrogels. Recently, scientists have proposed a variety of Phe-Phe-based macroscopic supramolecular hydrogels and used them in biomedical applications. Therefore, we summarize the construction strategies of Phe-Phe-based macroscopic supramolecular hydrogels and list their represented biomedical applications (e.g., wound healing, eye protection, cancer therapy, etc.) since the birth of Phe-Phe-based supramolecular hydrogels. In addition, we present the perspectives and challenges of Phe-Phe-based macroscopic peptide hydrogels.

Platinum-based drugs and hydrogel: a promising anti-tumor combination

Platinum-based drugs are widely used as first-line anti-tumor chemotherapy agents. However, they also have nonnegligible side effects due to the free drugs in circulation. Therefore, it is necessary to develop efficient and safe delivery systems for better tumor cell targeting. Hydrogel is a promising anti-tumor drug carrier that can form a platinum/hydrogel combination system for drug release, which has shown better anti-tumor effects in some studies. However, there is a lack of systematic summary in this field. This review aims to provide a comprehensive overview of the platinum/hydrogel combination system with the following sections: firstly, an introduction of platinum-based drugs; secondly, an analysis of the platinum/hydrogel combination system; and thirdly, a discussion of the advantages of the hydrogel-based delivery system. We hope this review can offer some insights for the development of the platinum/hydrogel combination system for better cancer therapy.

Cancer Stem-Like Cells-Oriented Surface Self-Assembly to Conquer Radioresistance

Cancer stem-like cells (CSCs), capable of indefinite self-renewal and differentiation, are considered to be the root cause of tumor radiotherapy (RT) resistance. However, the CSCs-targeted therapy still remains to be a great challenge because they are commonly located in the deep tumor making drugs hard to approach, and their hypoxic and acidic niche can further aggravate radioresistance. Herein, based on the finding that hypoxic CSCs highly express carbonic anhydrase IX (CAIX) on the cell membrane, a CAIX-targeted induced in situ self-assembly system on the surface of CSC is reported to overcome hypoxic CSC-mediated radioresistance. Via the sequential processes of "monomer release-target accumulation-surface self-assembly", the constructed peptide-based drug delivery system (CA-Pt) exhibits the advantages of deep penetration, amplified CAIX inhibition, and enhanced cellular uptake, which greatly relieves the hypoxic and acidic microenvironment to promote the hypoxic CSC differentiation and combines with platinum to boost the RT-inducing DNA damage. In both lung cancer tumor mouse and zebrafish embryo models, CA-Pt treatment can effectively assist RT in suppressing tumor growth and preventing tumor invasion and metastasis. This study uses a surface-induced self-assembly strategy to differentiate hypoxic CSCs, which may provide a universal treatment strategy for overcoming tumor radioresistance.

Peptide-Based Low Molecular Weight Photosensitive Supramolecular Gelators

Over the last couple of decades, stimuli-responsive supramolecular gels comprising synthetic short peptides as building blocks have been explored for various biological and material applications. Though a wide range of stimuli has been tested depending on the structure of the peptides, light as a stimulus has attracted extensive attention due to its non-invasive, non-contaminant, and remotely controllable nature, precise spatial and temporal resolution, and wavelength tunability. The integration of molecular photo-switch and low-molecular-weight synthetic peptides may thus provide access to supramolecular self-assembled systems, notably supramolecular gels, which may be used to create dynamic, light-responsive "smart" materials with a variety of structures and functions. This short review summarizes the recent advancement in the area of light-sensitive peptide gelation. At first, a glimpse of commonly used molecular photo-switches is given, followed by a detailed description of their incorporation into peptide sequences to design light-responsive peptide gels and the mechanism of their action. Finally, the challenges and future perspectives for developing next-generation photo-responsive gels and materials are outlined.

Injectable and pH-responsive self-assembled peptide hydrogel for promoted tumor cell uptake and enhanced cancer chemotherapy

Chemotherapy is the main treatment for cancer therapy. However, its anti-tumor efficiency is always impaired by the poor bioavailability and low tumor accumulation of chemotherapeutic drugs. The variation between the tumor microenvironment and normal tissue has been recognized as an effective tool to improve drug anti-tumor efficiency. Herein, we developed an injectable, pH-responsive, in situ self-assembled drug-peptide hydrogel (MTX-KKFKFEFEF(DA)) for highly efficient local tumor chemotherapy with few side effects. The small molecule drug, methotrexate (MTX), and pH-responsive linker, 2,3-dimethylmaleic anhydride (DA), were facilely conjugated onto the chain of the KKFKFEFEF peptide via an amidation reaction. The negatively charged drug-peptide (pH 7.4) can be activated to be positive and achieve a sol-gel phase transition under an acidic microenvironment (pH 6.5) both in vitro and in vivo, resulting in highly efficient cellular uptake and endocytosis capacities. Moreover, the in vivo anti-tumor therapeutic effect revealed that the MTX-KKFKFEFEF(DA) hydrogel exhibits long-term tumor retention time, much better tumor inhibition rate and negligible side effects after intratumoral injection into breast tumor-bearing mice. Therefore, this study reveals a versatile strategy for fabricating a pH-responsive drug-peptide hydrogel to improve the chemotherapeutic efficacy of drugs in cancer treatment.

Interactions of Analgesics with Cisplatin: Modulation of Anticancer Efficacy and Potential Organ Toxicity

Cisplatin (CDDP), one of the most eminent cancer chemotherapeutic agents, has been successfully used to treat more than half of all known cancers worldwide. Despite its effectiveness, CDDP might cause severe toxic adverse effects on multiple body organs during cancer chemotherapy, including the kidneys, heart, liver, gastrointestinal tract, and auditory system, as well as peripheral nerves causing severely painful neuropathy. The latter, among other pains patients feel during chemotherapy, is an indication for the use of analgesics during treatment with CDDP. Different types of analgesics, such as acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDS), and narcotic analgesics, could be used according to the severity of pain. Administered analgesics might modulate CDDP’s efficacy as an anticancer drug. NSAIDS, on one hand, might have cytotoxic effects on their own and few of them can potentiate CDDP’s anticancer effects via inhibiting the CDDP-induced cyclooxygenase (COX) enzyme, or through COX-independent mechanisms. On the other hand, some narcotic analgesics might ameliorate CDDP’s anti-neoplastic effects, causing chemotherapy to fail. Concerning safety, some analgesics share the same adverse effects on normal tissues as CDDP, augmenting its potentially hazardous effects on organ impairment. This article offers an overview of the reported literature on the interactions between analgesics and CDDP, paying special attention to possible mechanisms that modulate CDDP’s cytotoxic efficacy and potential adverse reactions.

γ-Ray-Triggered Drug Release of Reactive Oxygen Species-Sensitive Nanomedicine for Enhanced Concurrent Chemoradiation Therapy

Radiotherapy (RT) combined with chemotherapy remains a dominant therapeutic manner in clinical tumor treatment, which is irreplaceable in a short term. To seek an intrinsic connection of combined chemoradiation therapy and maximize the antitumor efficacy, we developed a reactive oxygen species (ROS)-sensitive nanomicelle drug delivery system based on a self-assembled amphiphilic polymer, hyaluronic acid-graft-poly-(propylene sulfide) (HA-PPS). A chemical radiosensitizer, doxorubicin (DOX), was encapsulated into the core of HA-PPS nanomicelles, constituting the DOX-loaded nanomicelles (HA-PPS@DOX NMs) with a spherical structure of around 205.10 ± 11.33 nm diameter with a narrow polydispersity index (PDI) of 0.135 ± 0.01. When combined with RT, the ROS-sensitive HA-PPS@DOX NMs disintegrated and released great drug cargos, which further enhanced cytotoxicity. Meanwhile, as a radiosensitizer, the released DOX sensitized cancer cells to radiotherapy, which has been confirmed by an enhanced sensitizer enhancement ratio (SER) value of 1.78 contributing to the increased cytotoxicity of concurrent chemoradiation tumor therapy, as evidenced by the improvement of half maximal inhibitory concentration (IC₅₀ value) of DOX from 2.316 to 0.8235 μg/mL. Moreover, in vivo studies revealed that HA-PPS@DOX NMs exhibited prolonged circulation time and improved tumor accumulation. Particularly, the released DOX triggered by radiation strengthened radiotherapy sensitization in return. Consequently, these superiorities of HA-PPS@DOX NMs shown by the concurrent chemoradiation tumor therapy resulted in an ideal tumor inhibition rate of 70.4%, thus providing a promising ROS-sensitive nanomedicine for cancer treatment.