A targeted near-infrared nanoprobe for deep-tissue penetration and imaging of prostate cancer

Clinical applications of nanoprobes of high-resolution in vivo imaging

Currently, the primary imaging methods used in clinical diagnosis are X-ray, computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), PET-CT, etc. The sensitivity and accuracy of these imaging methods bring many difficulties in clinical diagnosis; at the same time, CT, X-ray, PET-CT, etc. can cause radiation to the human body; some invasive operations of the gold standard bring much pain to the patients. Some of these tests are costly and do not allow real-time in vivo imaging (IVI). For these reasons, a new field of nanoprobes is gradually being developed in the clinical direction. Nanoprobes are known for their noninvasive, highly sensitive, real-time IVI and can even be expanded to intracellular imaging. This paper introduces the mainstream nanomaterial probes and reviews them regarding imaging means, imaging principles, biosafety, and clinical application effects.

Synergistic Potential of Nanomedicine in Prostate Cancer Immunotherapy: Breakthroughs and Prospects

Given the global prevalence of prostate cancer in men, it is crucial to explore more effective treatment strategies. Recently, immunotherapy has emerged as a promising cancer treatment due to its unique mechanism of action and potential long-term effectiveness. However, its limited efficacy in prostate cancer has prompted renewed interest in developing strategies to improve immunotherapy outcomes. Nanomedicine offers a novel perspective on cancer treatment with its unique size effects and surface properties. By employing targeted delivery, controlled release, and enhanced immunogenicity, nanoparticles can be synergized with nanomedicine platforms to amplify the effectiveness of immunotherapy in treating prostate cancer. Simultaneously, nanotechnology can address the limitations of immunotherapy and the challenges of immune escape and tumor microenvironment regulation. Additionally, the synergistic effects of combining nanomedicine with other therapies offer promising clinical outcomes. Innovative applications of nanomedicine include smart nanocarriers, stimulus-responsive systems, and precision medicine approaches to overcome translational obstacles in prostate cancer immunotherapy. This review highlights the transformative potential of nanomedicine in enhancing prostate cancer immunotherapy and emphasizes the need for interdisciplinary collaboration to drive research and clinical applications forward.

Peptide-mediated targeting of Quantum Dots in a 3D model of head and neck cancer

BACKGROUND

Oral squamous cell carcinoma (OSCC) treatment mainly relies on surgery. The status of surgical margin is a major prognostic factor for patients as positive margins are associated with lower survival. However, the anatomical particularities of this area complicate margin establishment. Fluorescence guided surgery (FGS) could be employed as an intraoperative technique to improve tumor resection and margin investigation. Quantum dots (QDs) serve as ideal contrast agents in this technique due to their brightness and stability. Since αVβ6 integrin is overexpressed in OSCC, coupling QDs with A20FMDV2 peptide (QDs-A20) targeting the αVβ6 integrin constitute a real opportunity. This study investigates the accumulation of QDs-A20 in 2D and 3D tongue cancer models, as well as QDs coupled to a scrambled version of this peptide (QDs-Scr) or without peptide (QDs-SPP), for imaging purposes.

METHODS

CdSeCdS/ZnS quantum dots were coated with sulfobetaine polymers (QDs-SPP) and conjugated to A20FMDV2 peptide (QDs-A20) or its scrambled version (QDs-Scr). Two-dimensional (2D) and three-dimensional (3D) tongue cancer cells HSC-3 were employed to test the effectiveness of intracellular accumulation of all types of QDs. Targeting ability of each QDs was assessed by flow cytometry, while the depth of penetration into cancerous spheroids was assessed by fluorescence microscopy.

RESULTS

QDs coating with sulfobetaines polymers (QDs-SPP) completely prevented their internalization by HSC-3 cells in 2D and 3D models, making QDs stealthy and preventing their non-specific accumulation. Conversely, peptides conjugated QDs (QDs-A20 & QDs-Scr) labeled HSC-3 monolayers and managed to label spheroid periphery up to 23 µm deep. However, no difference in accumulation was found between these two QDs whereas only A20 peptide could potentially target αVβ6 integrin. It appears that peptide conjugation increased QDs zeta potential, promoting their adsorption and subsequent endocytosis by cells, independently from αVβ6 integrin.

CONCLUSIONS

The present study highlighted the impact of peptide conjugation on QDs internalization in 2D and 3D tongue cancer cell models. QDs-SPP were stealthy and did not accumulate in cells. Peptides conjugated QDs could be used as contrast agents, but in a passive targeting approach. Modifications to surface chemistry are required to target αVβ6 integrin through active targeting. This study also highlights the need for controls such as scrambled peptides, the absence of which can lead to misinterpretation of results.

The utilization of quantum dot labeling as a burgeoning technique in the field of biological imaging

Quantum dots (QDs), with their unique optical and physical properties, have revolutionized the field of biological imaging, providing researchers with tools to explore cellular processes and molecular interactions in unprecedented detail. This review explores the diverse properties of QDs, emphasizing their application in biological imaging and addressing both their advantages and challenges. We discuss the developments in QD technology that have facilitated their integration into bioimaging, highlighting the role of surface modifications in enhancing their biocompatibility and functionality. The varied applications of QDs in both in vitro and in vivo imaging settings are examined, showcasing their capacity to deliver brighter, more stable, and multiplexed imaging solutions compared to traditional fluorescent dyes. Furthermore, we delve into the challenges associated with QD use, particularly concerns regarding their potential toxicity and long-term effects on biological systems, and explore ongoing research aimed at mitigating these issues. Finally, we discuss future directions in QD technology, anticipating advancements that will further solidify their role in biological imaging and open up new avenues for scientific exploration.

A cell-impermeable luminogenic probe for near-infrared imaging of prostate-specific membrane antigen in prostate cancer microenvironments

Prostate-specific membrane antigen (PSMA) imaging probes are a promising tool for the diagnosis and image-guided surgery of prostate cancer (PCa). However, PSMA-specific luminescence probes for PCa detection and heterogeneity studies with high imaging contrast are lacking. Here, we report the first near-infrared (NIR) iridium(III) complex for the wash-free and specific imaging of PSMA in PCa cells and spheroids. The conjugation of a PSMA inhibitor, Lys-urea-Glu, to an iridium(III) complex synergizes the PSMA-specific affinity and biocompatibility of the inhibitor with the desirable photophysical properties of the iridium(III) complex, including NIR emission (670 nm), high photostability and a large Stokes shift. The cellular impermeability of the probe along with its strong binding affinity to PSMA enhances its specificity for PSMA, enabling the washing-free luminescent imaging of membrane PSMA with lower cytotoxicity. The probe was successfully applied for selectively visualizing PSMA-expressing cells and for the imaging of PSMA in a multicellular PCa model with good imaging penetration, indicating its potential use in complicated and heterogeneous tumor microenvironments. Furthermore, the probe showed good imaging performance in the PCa-bearing tumor mice via targeting PSMA in vivo. This work provides a novel strategy for the development of highly sensitive and specific NIR probes for PSMA in biological systems in vitro, which is of great significance for the precise diagnosis of PCa and for elucidating PCa heterogeneity.

A Rare-Earth Near-Infrared Nanoprobe for the Identification of Small Cell Lung Cancer

Background

Small cell lung cancer (SCLC) is a common subtype of lung cancer, and there is currently no established method for the early identification of SCLC. We prepared a novel rare-earth near-infrared (NIR) downconversion nanoprobe to identify SCLC cells.

Methods

The shell precursors Gd-OA and Na-TFA-OA were prepared, and the NaYF4:Nd@NaGdF4-ProGRP antibody probe was obtained after synthesizing downconversion fluorescent nanocrystals. The probe was used for NIR identification of cancer cells and subcutaneous tumors in nude mice. The biotoxicity of the probe to SCLC cells and nude mice was studied.

Results

The NaYF4:Nd@NaGdF4-ProGRP antibody probe was successfully prepared, with a size of 44 nm, an NIR emission peak at approximately 1060 nm, and a concentration of 40 μmol/mL. The probe could achieve accurate NIR identification of SCLC cells and subcutaneous tumors in nude mice. Optimal images of the subcutaneous tumor model were obtained approximately 10 minutes after probe injection. There was no significant change in the hematology indices, respiratory rate, or heart rate of nude mice after the probe was injected (all P > 0.05).

Conclusion

We have successfully prepared a low-toxicity probe that can identify SCLC cells, which may be useful for the early detection of SCLC. And conduct theoretical exploration for non-invasive identification and identification of some early metastatic lesions without pathological sampling in the future.

Preparation and in vivo imaging of NIR-emissive carbonized polymer dots derived from biomass olive leaves with a quantum yield of 71.4

The conversion of biomass materials into high value-added chemicals is receiving more and more attention. Herein, biomass olive leaves are converted into carbonized polymer dots (CPDs) through a simple hydrothermal reaction. The CPDs show near infrared light emission properties, and the absolute quantum yield reaches a record breaking value of 71.4% under the excitation wavelength of 413 nm. Detailed characterization determines that CPDs only contain three elements: carbon, hydrogen and oxygen, which is very different from most carbon dots which contain nitrogen atoms. Subsequently, NIR fluorescence imaging both in vitro and in vivo is performed to test their feasibility as fluorescence probes. The metabolic pathways of CPDs in the living body are inferred by studying the bio-distribution of CPDs in major organs. Their outstanding advantage is expected to further broaden the application field of this material.

Current applications of nanomaterials in urinary system tumors

The development of nanotechnology and nanomaterials has provided insights into the treatment of urinary system tumors. Nanoparticles can be used as sensitizers or carriers to transport drugs. Some nanoparticles have intrinsic therapeutic effects on tumor cells. Poor patient prognosis and highly drug-resistant malignant urinary tumors are worrisome to clinicians. The application of nanomaterials and the associated technology against urinary system tumors offers the possibility of improving treatment. At present, many achievements have been made in the application of nanomaterials against urinary system tumors. This review summarizes the latest research on nanomaterials in the diagnosis and treatment of urinary system tumors and provides novel ideas for future research on nanotechnologies in this field.

Affinity probes based on small-molecule inhibitors for tumor imaging

Methods for molecular imaging of target areas, including optical imaging, radionuclide imaging, magnetic resonance imaging and other imaging technologies, are helpful for the early diagnosis and precise treatment of cancers. In addition to cancer management, small-molecule inhibitors are also used for developing cancer target probes since they act as the tight-binding ligands of overexpressed proteins in cancer cells. This review aims to summarize the structural designs of affinity probes based on small-molecule inhibitors from the aspects of the inhibitor, linker, dye and radionuclide, and discusses the influence of the modification of these structures on affinity and pharmacokinetics. We also present examples of inhibitor affinity probes in clinical applications, and these summaries will provide insights for future research and clinical translations.

Quantum Dots Mediated Imaging and Phototherapy in Cancer Spheroid Models: State of the Art and Perspectives

Quantum Dots (QDs) are fluorescent nanoparticles known for their exceptional optical properties, i.e., high fluorescence emission, photostability, narrow emission spectrum, and broad excitation wavelength. These properties make QDs an exciting choice for bioimaging applications, notably in cancer imaging. Challenges lie in their ability to specifically label targeted cells. Numerous studies have been carried out with QDs coupled to various ligands like peptides, antibodies, aptamers, etc., to achieve efficient targeting. Most studies were conducted in vitro with two-dimensional cell monolayers (n = 8902) before evolving towards more sophisticated models. Three-dimensional multicellular tumor models better recapitulate in vivo conditions by mimicking cell-to-cell and cell-matrix interactions. To date, only few studies (n = 34) were conducted in 3D in vitro models such as spheroids, whereas these models could better represent QDs behavior in tumors compared to monolayers. Thus, the purpose of this review is to present a state of the art on the studies conducted with Quantum Dots on spheroid models for imaging and phototherapy purposes.

Membrane dual-targeting probes: A promising strategy for fluorescence-guided prostate cancer surgery and lymph node metastases detection

Fluorescence-guided surgery (FGS) with tumor-targeted imaging agents, particularly those using the near-infrared wavelength, has emerged as a real-time technique to highlight the tumor location and margins during a surgical procedure. For accurate visualization of prostate cancer (PCa) boundary and lymphatic metastasis, we developed a new approach involving an efficient self-quenched near-infrared fluorescence probe, Cy-KUE-OA, with dual PCa-membrane affinity. Cy-KUE-OA specifically targeted the prostate-specific membrane antigen (PSMA), anchored into the phospholipids of the cell membrane of PCa cells and consequently showed a strong Cy7-de-quenching effect. This dual-membrane-targeting probe allowed us to detect PSMA-expressing PCa cells both in vitro and in vivo and enabled clear visualization of the tumor boundary during fluorescence-guided laparoscopic surgery in PCa mouse models. Furthermore, the high PCa preference of Cy-KUE-OA was confirmed on surgically resected patient specimens of healthy tissues, PCa, and lymph node metastases. Taken together, our results serve as a bridge between preclinical and clinical research in FGS of PCa and lay a solid foundation for further clinical research.

Nanomedicine for urologic cancers: diagnosis and management

Urologic cancers accounted for more than 2 million new cases and around 0.8 million deaths in 2020. Although surgery, chemotherapy, and radiotherapy, as well as castration for prostate cancer, remain the cornerstones for managing urologic neoplasms, they can result in severe adverse effects, poor patient compliance, and unsatisfactory survival rates, thus, it is essential to develop novel options that enable the early detection of these malignancies, together with providing accurate diagnoses, and more efficient treatment strategies. Nanomedicine represents an emerging approach that can deliver formulations or drugs across traditional biological barriers in the body and be directed to specific cell types within target organs via active targeting or passive targeting, thus, showing potential to improve the management of urologic cancers. In this review, we discussed the most recent updates on the application of nanomedicines in the diagnosis and treatment of urologic cancers, with focus on prostate, bladder and kidney tumors. We also presented the anti-tumor molecular mechanisms of newly designed nanomedicine for treating urologic cancers, mainly including image-guided surgery, chemotherapy, radiotherapy, gene therapy, immunotherapy, and their synergetic therapy. Current studies have demonstrated the potential advantages of nanomedicine over conventional approaches. However, most developments and new findings in this area have not been validated in clinical trials yet, and therefore, efforts shall be made to translate these research insights into clinical practices for urologic cancers.

Advances of Light/Ultrasound/Magnetic-Responsive Nanoprobes for Visualized Theranostics of Urinary Tumors

Light/ultrasound/magnetic-responsive nanomaterials exhibit excellent performance in imaging and therapy and play an important role in precision theranostics of tumors. In contrast to deep organs, urinary organs (such as bladder and prostate) can easily be studied via intervention mode, which has greatly brought promising applications of stimuli-responsive nanoprobes in visualized theranostics of urinary tumors. Therefore, it has been very critical to develop stimuli-responsive nanoprobes with high safety, stability, and reliability against urinary tumors. In this review, recent advances in light/ultrasound/magnetic-responsive nanoprobes in visualized theranostics of urinary tumors are summarized, including magnetic resonance/fluorescence/ultrasound/photoacoustic imaging and multimodal imaging, photothermal/photodynamic/sonodynamic therapy and combination therapy, and single-modal/multimodal-imaging-guided visualized theranostics. Finally, the future perspectives of light/ultrasound/magnetic-responsive nanoprobes against urinary tumors are also prospected.

Agarose Micro-Well Platform for Rapid Generation of Homogenous 3D Tumor Spheroids

In recent years, 3D culture of tumor spheroids has managed to revolutionize cancer research and drug discovery. 2D monolayer cells grown in cell culture flasks undergo radical changes in cell behavior, structure, and function owing to varying environmental cues and are unable to provide predictive data for preclinical evaluation. 3D tumor spheroids can better recapitulate tumor architecture, cell-cell and cell-matrix connectivity, and the tissue complexity of tumors grown in animal models. However, many of the existing techniques to culture 3D spheroids are time-consuming and ineffective and produce irregular-shaped spheroids that cannot be easily incorporated in biological assays. The set of protocols described herein makes use of a commercial hair brush as a template to create concave micro-well impressions in agarose. This technique is easy, inexpensive, and adaptable and also has the ability to produce uniform, homogenous cancer spheroids, with large diameter (∼1000 μm) and thickness (∼250 μm), within 24 to 48 hr after cell seeding. The 3D spheroids produced using the agarose micro-well platform function as an excellent 3D in vitro model for understanding the extent of penetration, uptake, and distribution of targeted cargos such as a diagnostic or therapeutic agents for identification and treatment of cancer. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Fabrication of agarose micro-well scaffold for growing tumor spheroids using a commercial hair brush Basic Protocol 2: Formation of homogenous tumor spheroids in agarose micro-well platform Basic Protocol 3: Assessing viability of 3D tumor spheroids grown in agarose micro-wells using confocal microscopy Basic Protocol 4: Analyzing uptake and penetration of targeted fluorescent bioconjugate in 3D tumor spheroids using two-photon imaging.