Polymer Nanoplatforms at Work in Prostate Cancer Therapy

Clinical insights into nanomedicine and biosafety: advanced therapeutic approaches for common urological cancers

Urological cancers including those of the prostate, bladder, and kidney, are prevalent and often lethal malignancies besides other less common ones like testicular and penile cancers. Current treatments have major limitations like side effects, recurrence, resistance, high costs, and poor quality of life. Nanotechnology offers promising solutions through enhanced diagnostic accuracy, targeted drug delivery, controlled release, and multimodal imaging. This review reflects clinical challenges and nanomedical advances across major urological cancers. In prostate cancer, nanoparticles improve delineation and radiosensitization in radiation therapy, enable fluorescent guidance in surgery, and enhance chemotherapy penetration in metastatic disease. Nanoparticles also overcome bladder permeability barriers to increase the residence time of intravesical therapy and chemotherapy agents. In renal cancer, nanocarriers potentiate tyrosine kinase inhibitors and immunotherapy while gene vectors and zinc oxide nanoparticles demonstrate antiproliferative effects. Across modalities, urological applications of nanomedicine include polymeric, liposomal, and metal nanoparticles for targeted therapy, prodrug delivery, photodynamic therapy, and thermal ablation. Biosafety assessments reveal favorable profiles but clinical translation remains limited, necessitating further trials. In conclusion, nanotechnology holds significant potential for earlier detection, precise intervention, and tailored treatment of urological malignancies, warranting expanded research to transform patient outcomes.

Enhancing Cancer Chemo-Immunotherapy: Innovative Approaches for Overcoming Immunosuppression by Functional Nanomaterials

Chemotherapy is a critical modality in cancer therapy to combat malignant cell proliferation by directly attacking cancer cells and inducing immunogenic cell death, serving as a vital component of multi-modal treatment strategies for enhanced therapeutic outcomes. However, chemotherapy may inadvertently contribute to the immunosuppression of the tumor microenvironment (TME), inducing the suppression of antitumor immune responses, which can ultimately affect therapeutic efficacy. Chemo-immunotherapy, combining chemotherapy and immunotherapy in cancer treatment, has emerged as a ground-breaking approach to target and eliminate malignant tumors and revolutionize the treatment landscape, offering promising, durable responses for various malignancies. Notably, functional nanomaterials have substantially contributed to chemo-immunotherapy by co-delivering chemo-immunotherapeutic agents and modulating TME. In this review, recent advancements in chemo-immunotherapy are thus summarized to enhance treatment effectiveness, achieved by reversing the immunosuppressive TME (ITME) through the exploitation of immunotherapeutic drugs, or immunoregulatory nanomaterials. The effects of two-way immunomodulation and the causes of immunoaugmentation and suppression during chemotherapy are illustrated. The current strategies of chemo-immunotherapy to surmount the ITME and the functional materials to target and regulate the ITME are discussed and compared. The perspective on tumor immunosuppression reversal strategy is finally proposed.

Nanomedicine Penetration to Tumor: Challenges, and Advanced Strategies to Tackle This Issue

Nanomedicine has been under investigation for several years to improve the efficiency of chemotherapeutics, having minimal pharmacological effects clinically. Ineffective tumor penetration is mediated by tumor environments, including limited vascular system, rising cancer cells, higher interstitial pressure, and extra-cellular matrix, among other things. Thus far, numerous methods to increase nanomedicine access to tumors have been described, including the manipulation of tumor micro-environments and the improvement of nanomedicine characteristics; however, such outdated approaches still have shortcomings. Multi-functional convertible nanocarriers have recently been developed as an innovative nanomedicine generation with excellent tumor infiltration abilities, such as tumor-penetrating peptide-mediated transcellular transport. The developments and limitations of nanomedicines, as well as expectations for better outcomes of tumor penetration, are discussed in this review.

Development of poly (p-coumaric acid) as a self-anticancer nanocarrier for efficient and biosafe cancer therapy

Biocompatible polymers with potential therapeutic activity present an appealing strategy for the development of new functional drug carriers. In this study, we report the synthesis of therapeutic poly(p-coumaric acid) (PCA)...

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Dual pH- and Glutathione-Responsive CO2-Generating Nanodrug Delivery System for Contrast-Enhanced Ultrasonography and Therapy of Prostate Cancer

Ultrasonography (US) contrast imaging using US contrast agents has been widely applied for the diagnosis and differential diagnosis of tumors. Commercial US contrast agents have limited applications because of their large size and shorter imaging time. At the same time, the desired therapeutic purpose cannot be achieved by applying only conventional US contrast agents. The development of nanoscale US agents with US imaging and therapeutic functions has attracted increasing attention. In this study, we successfully developed DOX-loaded poly-1,6-hexanedithiol-sodium bicarbonate nanoparticles (DOX@HADT-SS-NaHCO3 NPs) with pH-responsive NaHCO3 and GSH-responsive disulfide linkages. DOX@HADT-SS-NaHCO3 NPs underwent acid-triggered decomposition of NaHCO3 to generate CO2 bubbles and a reduction of disulfide linkages to further promote the release of CO2 and DOX. The potential of DOX@HADT-SS-NaHCO3 NPs for contrast-enhanced US imaging and therapy of prostate cancer was thoroughly evaluated using in vitro agarose gel phantoms and a C4-2 tumor-bearing nude mice model. These polymeric NPs displayed significantly enhanced US contrast at acidic pH and antitumor efficacy. Therefore, the NaHCO3 and DOX-encapsulated polymeric NPs hold tremendous potential for effective US imaging and therapy of prostate cancer.

Multifunctional red carbon dots: a theranostic platform for magnetic resonance imaging and fluorescence imaging-guided chemodynamic therapy

In recent years, carbon dots (CDs) with red-emitting wavelengths have received increasing attention in cancer therapy and imaging. Here, we reported a multi-functional CD based platform combining bimodal magnetic resonance/fluorescence (MR/FL) imaging and chemodynamic therapy (CDT) for in vivo imaging of tumor tissues and efficient anticancer treatment. The red-emitting CDs were synthesized via a one-step solvothermal method with p-phenylenediamine as the carbon source. Ethylenediaminetetraacetic acid (EDTA) was covalently coupled to the surface of CDs and then complexed with Fe2+ and Gd3+ to obtain functionalized red CDs (CDs@EDTA@Gd@Fe). CDs@EDTA@Gd@Fe exhibited bright and stable fluorescence and strong T1-weighted MR imaging (MRI) contrast. Moreover, the CDs@EDTA@Gd@Fe showed an excellent anticancer effect both in vitro and in vivo via a Fenton reaction-based CDT by releasing Fe2+ in the tumor. Our study offers a promising strategy for developing multi-functional CDs for cancer theranostics.

A Tumbling Magnetic Microrobot System for Biomedical Applications

A microrobot system comprising an untethered tumbling magnetic microrobot, a two-degree-of-freedom rotating permanent magnet, and an ultrasound imaging system has been developed for in vitro and in vivo biomedical applications. The microrobot tumbles end-over-end in a net forward motion due to applied magnetic torque from the rotating magnet. By turning the rotational axis of the magnet, two-dimensional directional control is possible and the microrobot was steered along various trajectories, including a circular path and P-shaped path. The microrobot is capable of moving over the unstructured terrain within a murine colon in in vitro, in situ, and in vivo conditions, as well as a porcine colon in ex vivo conditions. High-frequency ultrasound imaging allows for real-time determination of the microrobot's position while it is optically occluded by animal tissue. When coated with a fluorescein payload, the microrobot was shown to release the majority of the payload over a 1-h time period in phosphate-buffered saline. Cytotoxicity tests demonstrated that the microrobot's constituent materials, SU-8 and polydimethylsiloxane (PDMS), did not show a statistically significant difference in toxicity to murine fibroblasts from the negative control, even when the materials were doped with magnetic neodymium microparticles. The microrobot system's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.

pH-triggered morphological change in a self-assembling amphiphilic peptide used as an antitumor drug carrier

The geometry of nanoparticles plays an important role in the process of drug encapsulation and release. In this study, an acid-responsive amphiphilic polypeptide consisting of lysine and leucine was prepared. In neutral media, the amphiphilic peptide L₆K₄ self-assembled to form spherical nanoparticles and encapsulated fat-soluble antitumor drugs. The intratumoral accumulation of the drug-loaded nanoparticles was improved in HeLa cells compared with normal cells. Compared to a neutral environment, increasingly acidic solutions changed the secondary structure of the peptide. In addition, the drug-loaded nanoparticles expanded and decomposed, rapidly releasing the poorly soluble antitumor drug doxorubicin (DOX). In addition, the amphiphilic peptide L₆K₄ had antitumor properties, and the antitumor performance of the combination of L₆K₄ and DOX was better than that of free DOX. Our results indicate that the use of acid responsiveness to induce geometric changes in drug-loaded peptide nanoparticles could be a promising strategy for antitumor drug delivery.

Acidity-responsive shell-sheddable camptothecin-based nanofibers for carrier-free cancer drug delivery

Small molecular prodrugs that self-assemble into nanoparticles have many advantages over commonly studied nanomedicines based upon nanoscale carriers such as liposomes, micelles and polymeric nanoparticles. These carrier-free nanodrugs exhibit favorable nanoproperties without the help of a nanocarrier, and they have many unique merits, such as a simple synthetic procedure, well-defined structure and high drug loading capacity. To date, most of these carrier-free nanodrugs have been spherical and very few nonspherical nanodrugs have been synthesized and studied. Herein, we report a camptothecin (CPT) prodrug that self-assembles into nanofibers. These carrier-free CPT nanofibers have a width of approximately one hundred nanometers and a length of several micrometers. The cellular uptake and tumor penetration behaviour of these nanofibers were observed by time-lapse video microscopy. These nanofibers can rapidly enter cancer cells by penetrating the cell membrane, gradually dissolve intracellularly and efficiently release the active drug. Coating the surface of these nanofibers with a pH-responsive PEG layer improves the stability of these nanofibers and shields their positive charge to minimize nonspecific interactions. These pH-responsive nanofibers are sheddable in the acidic tumor microenvironment and deliver carried cargoes deep into tumors. Our findings demonstrate that small molecular CPT prodrugs that form nanofibers are efficient for cancer drug delivery.

Supramolecular micellar drug delivery system based on multi-arm block copolymer for highly effective encapsulation and sustained-release chemotherapy

A novel multi-arm polyphosphoester-based nanomaterial provides high drug loading efficiency and sustained-release drug delivery for effective chemotherapy.