Development and evaluation of an ultrasound-triggered microbubble combined transarterial chemoembolization (TACE) formulation on rabbit VX2 liver cancer model

Bridging Smart Nanosystems with Clinically Relevant Models and Advanced Imaging for Precision Drug Delivery

Intracellular delivery of nano-drug-carriers (NDC) to specific cells, diseased regions, or solid tumors has entered the era of precision medicine that requires systematic knowledge of nano-biological interactions from multidisciplinary perspectives. To this end, this review first provides an overview of membrane-disruption methods such as electroporation, sonoporation, photoporation, microfluidic delivery, and microinjection with the merits of high-throughput and enhanced efficiency for in vitro NDC delivery. The impact of NDC characteristics including particle size, shape, charge, hydrophobicity, and elasticity on cellular uptake are elaborated and several types of NDC systems aiming for hierarchical targeting and delivery in vivo are reviewed. Emerging in vitro or ex vivo human/animal-derived pathophysiological models are further explored and highly recommended for use in NDC studies since they might mimic in vivo delivery features and fill the translational gaps from animals to humans. The exploration of modern microscopy techniques for precise nanoparticle (NP) tracking at the cellular, organ, and organismal levels informs the tailored development of NDCs for in vivo application and clinical translation. Overall, the review integrates the latest insights into smart nanosystem engineering, physiological models, imaging-based validation tools, all directed towards enhancing the precise and efficient intracellular delivery of NDCs.

In Situ Insonation of Alkaline Buffer Containing Liposomes Leads to a Net Improvement of the Therapeutic Outcome in a Triple Negative Breast Cancer Murine Model

Breast cancer is characterized by an acidic micro-environment. Acidic extracellular pH gives cancer cells an evolutionary advantage, hence, neutralization of the extracellular pH has been considered as a potential therapeutic strategy. To address the issue of systemic pH alteration, an approach based on the targeted delivery of the buffering solution to the tumor region is investigated. The method relies on the use of low frequency ultrasound and sono-sensitive liposomes loaded with buffers at alkaline pH (LipHUS). After the i.v. injection of LipHUS, the application of ultrasound (US) at the sites of the pathology induces a local increase of pH that results highly effective in i) inhibiting primary tumor growth, ii) reducing tumor recurrence after surgery, and iii) suppressing metastases' formation. The experiments are carried out on a triple negative breast cancer mouse model. The results obtained demonstrate that localized and triggered release of bicarbonate or PBS buffer from sonosensitive liposomes represents an efficient therapeutic tool for treating triple-negative breast cancer. This approach holds promise for potential clinical translation.

Emulsifying Lipiodol with pH-sensitive DOX@HmA nanoparticles for hepatocellular carcinoma TACE treatment eliminate metastasis

Lipiodol-based transcatheter arterial chemoembolization (TACE) is currently the predominant and first-line treatment option recommended by the global standard for unresectable hepatocellular carcinoma (HCC). However, the unstable emulsion of Lipiodol causes a substantial proportion of chemotherapy drugs to enter the circulation system, leading to poor accumulation in cancer tissues and unexpected side effects of chemotherapy drugs. Herein, we emulsified Lipiodol with a pH-sensitive drug delivery system assembled from hexahistidine and zinc ions (HmA) with a super-high loading capacity of doxorubicin (DOX) and a promising ability to penetrate bio-barriers for the effective treatment of HCC by TACE. In vitro tests showed that DOX@HmA was comparable to free DOX in killing HCC cells. Impressively, during the in vivo TACE treatment, the anti-tumor efficacy of DOX@HmA was significantly greater than that of free DOX, indicating that DOX@HmA increased the accumulation of DOX in tumor. Emulsifying Lipiodol with pH-sensitive DOX@HmA significantly inhibited cell regeneration and tumor angiogenesis and decreased the systemic side effects of chemotherapy, especially by suppressing pulmonary metastasis in liver VX2 tumors in rabbits by inhibiting epithelial-mesenchymal transition (EMT). Emulsifying tumor microenvironment-responsive drug delivery systems (DDSs) with Lipiodol could be a new strategy for clinical TACE chemotherapy with potentially enhanced HCC treatment.

Autophagy-Targeted Calcium Phosphate Nanoparticles Enable Transarterial Chemoembolization for Enhanced Cancer Therapy

Transarterial chemoembolization (TACE) is commonly used for treating advanced hepatocellular carcinoma (HCC). However, the instability of lipiodol-drug emulsion and the altered tumor microenvironment (TME, such as hypoxia-induced autophagy) postembolization are responsible for the unsatisfactory therapeutic outcomes. Herein, pH-responsive poly(acrylic acid)/calcium phosphate nanoparticles (PAA/CaP NPs) were synthesized and used as the carrier of epirubicin (EPI) to enhance the efficacy of TACE therapy through autophagy inhibition. PAA/CaP NPs have a high loading capacity of EPI and a sensitive drug release behavior under acidic conditions. Moreover, PAA/CaP NPs block autophagy through the dramatic increase of intracellular Ca²⁺ content, which synergistically enhances the toxicity of EPI. TACE with EPI-loaded PAA/CaP NPs dispersed in lipiodol shows an obvious enhanced therapeutic outcome compared to the treatment with EPI-lipiodol emulsion in an orthotopic rabbit liver cancer model. This study not only develops a new delivery system for TACE but also provides a promising strategy targeting autophagy inhibition to improve the therapeutic effect of TACE for the HCC treatment.

Multifunctional nanoplatforms application in the transcatheter chemoembolization against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has the sixth-highest new incidence and fourth-highest mortality worldwide. Transarterial chemoembolization (TACE) is one of the primary treatment strategies for unresectable HCC. However, the therapeutic effect is still unsatisfactory due to the insufficient distribution of antineoplastic drugs in tumor tissues and the worsened post-embolization tumor microenvironment (TME, e.g., hypoxia and reduced pH). Recently, using nanomaterials as a drug delivery platform for TACE therapy of HCC has been a research hotspot. With the development of nanotechnology, multifunctional nanoplatforms have been developed to embolize the tumor vasculature, creating conditions for improving the distribution and bioavailability of drugs in tumor tissues. Currently, the researchers are focusing on functionalizing nanomaterials to achieve high drug loading efficacy, thorough vascular embolization, tumor targeting, controlled sustained release of drugs, and real-time imaging in the TACE process to facilitate precise embolization and enable therapeutic procedures follow-up imaging of tumor lesions. Herein, we summarized the recent advances and applications of functionalized nanomaterials based on TACE against HCC, believing that developing these functionalized nanoplatforms may be a promising approach for improving the TACE therapeutic effect of HCC.

Short-term efficacy assessment of transarterial chemoembolization combined with radioactive iodine therapy in primary hepatocellular carcinoma

BACKGROUND

Transarterial chemoembolization (TACE) is an effective treatment for primary hepatocellular carcinoma (PHC). Radioactive iodine therapy has been used in the treatment of advanced PHC, especially in patients with portal vein tumor thrombosis. However, data on the therapeutic effect of TACE combined with radioactive iodine therapy in PHC are scarce.

AIM

To investigate the clinical efficacy of TACE combined with radioactive iodine implantation therapy in advanced PHC via perfusion computed tomography (CT).

METHODS

For this study, 98 advanced PHC patients were recruited and divided randomly into the study and control groups. Patients in the study group were treated with TACE combined radioactive iodine implantation therapy. Patients in the control group were treated with only TACE. The tumor lesion length, clinical effect, serum alpha-fetoprotein (AFP) and CT perfusion parameters were compared before and after therapy, and statistical analysis was performed.

RESULTS

There was no significant difference in tumor length and serum AFP between the study and control groups (P > 0.05) before treatment. However, the tumor length and serum AFP in the study group were lower than those in the control group 1 mo and 3 mo after therapy. After 3 mo of treatment, the complete and partial remission rate of the study group was 93.88%, which was significantly higher than the control group (77.55%) (P < 0.05). Before treatment, there were no significant differences between the two groups on the perfusion CT variables, including the lesion blood volume, permeability surface, blood flow, hepatic artery flow and mean transit time (P > 0.05). After 3 mo of treatment, all perfusion CT variables were lower in the study group compared to the control group (P < 0.05). The survival time of patients in the study group was 22 mo compared to 18 mo in the control group, which was significantly different [log rank (Mantel-Cox) = 4.318, P = 0.038].

CONCLUSION

TACE combined with radioactive iodine implantation in the treatment of advanced PHC can inhibit the formation of blood vessels in tumor tissue and reduce the perfusion level of tumor lesions, thereby improving the clinical efficacy and prolonging the survival time of patients.

Recent Advances in Stimuli-Responsive Doxorubicin Delivery Systems for Liver Cancer Therapy

Doxorubicin (DOX) is one of the most commonly used drugs in liver cancer. Unfortunately, the traditional chemotherapy with DOX presents many limitations, such as a systematic release of DOX, affecting both tumor tissue and healthy tissue, leading to the apparition of many side effects, multidrug resistance (MDR), and poor water solubility. Furthermore, drug delivery systems' responsiveness has been intensively studied according to the influence of different internal and external stimuli on the efficiency of therapeutic drugs. In this review, we discuss both internal stimuli-responsive drug-delivery systems, such as redox, pH and temperature variation, and external stimuli-responsive drug-delivery systems, such as the application of magnetic, photo-thermal, and electrical stimuli, for the controlled release of Doxorubicin in liver cancer therapy, along with the future perspectives of these smart delivery systems in liver cancer therapy.

Microbubble–Nanoparticle Complexes for Ultrasound-Enhanced Cargo Delivery

Targeted delivery of therapeutics to specific tissues is critically important for reducing systemic toxicity and optimizing therapeutic efficacy, especially in the case of cytotoxic drugs. Many strategies currently exist for targeting systemically administered drugs, and ultrasound-controlled targeting is a rapidly advancing strategy for externally-stimulated drug delivery. In this non-invasive method, ultrasound waves penetrate through tissue and stimulate gas-filled microbubbles, resulting in bubble rupture and biophysical effects that power delivery of attached cargo to surrounding cells. Drug delivery capabilities from ultrasound-sensitive microbubbles are greatly expanded when nanocarrier particles are attached to the bubble surface, and cargo loading is determined by the physicochemical properties of the nanoparticles. This review serves to highlight and discuss current microbubble–nanoparticle complex component materials and designs for ultrasound-mediated drug delivery. Nanocarriers that have been complexed with microbubbles for drug delivery include lipid-based, polymeric, lipid–polymer hybrid, protein, and inorganic nanoparticles. Several schemes exist for linking nanoparticles to microbubbles for efficient nanoparticle delivery, including biotin–avidin bridging, electrostatic bonding, and covalent linkages. When compared to unstimulated delivery, ultrasound-mediated cargo delivery enables enhanced cell uptake and accumulation of cargo in target organs and can result in improved therapeutic outcomes. These ultrasound-responsive delivery complexes can also be designed to facilitate other methods of targeting, including bioactive targeting ligands and responsivity to light or magnetic fields, and multi-level targeting can enhance therapeutic efficacy. Microbubble–nanoparticle complexes present a versatile platform for controlled drug delivery via ultrasound, allowing for enhanced tissue penetration and minimally invasive therapy. Future perspectives for application of this platform are also discussed in this review.

Polymersome-stabilized doxorubicin-lipiodol emulsions for high-efficacy chemoembolization therapy

Transarterial chemoembolization (TACE) with free doxorubicin-lipiodol emulsions (free DOX/L) is a favored clinical treatment for advanced hepatocellular carcinoma (HCC) patients ineligible for radical therapies; however, its inferior colloidal stability not only greatly reduces its tumor retention but also hastens drug release into blood circulation, leading to suboptimal clinical outcomes. Here, we find that disulfide-crosslinked polymersomes carrying doxorubicin (Ps-DOX) form super-stable and homogenous water-in-oil microemulsions with lipiodol (Ps-DOX/L). Ps-DOX/L microemulsions had tunable sizes ranging from 14 to 44 μm depending on the amount of Ps-DOX, were stable over 2 months storage as well as centrifugation, and exhibited nearly zero-order DOX release within 15 days. Of note, Ps-DOX induced 2.3-13.4 fold better inhibitory activity in all tested rat, murine and human liver tumor cells than free DOX likely due to its efficient redox-triggered intracellular drug release. Interestingly, transarterial administration of Ps-DOX/L microemulsions in orthotopic rat N1S1 syngeneic HCC model showed minimal systemic DOX exposure, high and long hepatic DOX retention, complete tumor elimination, effective inhibition of angiogenesis, and depleted adverse effects, significantly outperforming clinically used free DOX/L emulsions. This smart polymersome stabilization of doxorubicin-lipiodol microemulsions provides a novel TACE strategy for advanced tumors.

The Advances and Biomedical Applications of Imageable Nanomaterials

Nanomedicine shows great potential in screening, diagnosing and treating diseases. However, given the limitations of current technology, detection of some smaller lesions and drugs’ dynamic monitoring still need to be improved. With the advancement of nanotechnology, researchers have produced various nanomaterials with imaging capabilities which have shown great potential in biomedical research. Here, we summarized the researches based on the characteristics of imageable nanomaterials, highlighted the advantages and biomedical applications of imageable nanomaterials in the diagnosis and treatment of diseases, and discussed current challenges and prospects.

Ultrasound and Nanomedicine for Cancer-Targeted Drug Delivery: Screening, Cellular Mechanisms and Therapeutic Opportunities

Cancer is a disease characterized by abnormal cell growth. According to a report published by the World Health Organization (WHO), cancer is the second leading cause of death globally, responsible for an estimated 9.6 million deaths in 2018. It should be noted that ultrasound is already widely used as a diagnostic procedure for detecting tumorigenesis. In addition, ultrasound energy can also be utilized effectively for treating cancer. By filling the interior of lipospheres with gas molecules, these particles can serve both as contrast agents for ultrasonic imaging and as delivery systems for drugs such as microbubbles and nanobubbles. Therefore, this review aims to describe the nanoparticle-assisted drug delivery system and how it can enhance image analysis and biomedicine. The formation characteristics of nanoparticles indicate that they will accumulate at the tumor site upon ultrasonic imaging, in accordance with their modification characteristics. As a result of changing the accumulation of materials, it is possible to examine the results by comparing images of other tumor cell lines. It is also possible to investigate ultrasound images for evidence of cellular effects. In combination with a precision ultrasound imaging system, drug-carrying lipospheres can precisely track tumor tissue and deliver drugs to tumor cells to enhance the ability of this nanocomposite to treat cancer.

A pure nanoICG-based homogeneous lipiodol formulation: toward precise surgical navigation of primary liver cancer after long-term transcatheter arterial embolization

PURPOSE

To surmount the critical issues of indocyanine green (ICG), and thus achieving a precise surgical navigation of primary liver cancer after long-term transcatheter arterial embolization.

METHODS

In this study, a facile and green pure-nanomedicine formulation technology is developed to construct carrier-free indocyanine green nanoparticles (nanoICG), and which subsequently dispersed into lipiodol via a super-stable homogeneous lipiodol formulation technology (SHIFT nanoICG) for transcatheter arterial embolization combined near-infrared fluorescence-guided precise hepatectomy.

RESULTS

SHIFT nanoICG integrates excellent anti-photobleaching capacity, great optical imaging property, and specific tumoral deposition to recognize tumor regions, featuring entire-process enduring fluorescent-guided precise hepatectomy, especially in resection of the indiscoverable satellite lesions (0.6 mm × 0.4 mm) in rabbit bearing VX2 orthotopic hepatocellular carcinoma models.

CONCLUSION

Such a simple and effective strategy provides a promising avenue to address the clinical issue of clinical hepatectomy and has excellent potential for a translational pipeline.

Advances in liver US, CT, and MRI: moving toward the future

Over the past two decades, the epidemiology of chronic liver disease has changed with an increase in the prevalence of nonalcoholic fatty liver disease in parallel to the advent of curative treatments for hepatitis C. Recent developments provided new tools for diagnosis and monitoring of liver diseases based on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), as applied for assessing steatosis, fibrosis, and focal lesions. This narrative review aims to discuss the emerging approaches for qualitative and quantitative liver imaging, focusing on those expected to become adopted in clinical practice in the next 5 to 10 years. While radiomics is an emerging tool for many of these applications, dedicated techniques have been investigated for US (controlled attenuation parameter, backscatter coefficient, elastography methods such as point shear wave elastography [pSWE] and transient elastography [TE], novel Doppler techniques, and three-dimensional contrast-enhanced ultrasound [3D-CEUS]), CT (dual-energy, spectral photon counting, extracellular volume fraction, perfusion, and surface nodularity), and MRI (proton density fat fraction [PDFF], elastography [MRE], contrast enhancement index, relative enhancement, T1 mapping on the hepatobiliary phase, perfusion). Concurrently, the advent of abbreviated MRI protocols will help fulfill an increasing number of examination requests in an era of healthcare resource constraints.

Limitations and Possibilities of Transarterial Chemotherapeutic Treatment of Hepatocellular Carcinoma

Because diagnostic tools for discriminating between hepatocellular carcinoma (HCC) and advanced cirrhosis are poor, HCC is often detected in a stage where transarterial chemoembolization (TACE) is the best treatment option, even though it provides a poor survival gain. Despite having been used worldwide for several decades, TACE still has many limitations. First, there is a vast heterogeneity in the cellular composition and metabolism of HCCs as well as in the patient population, which renders it difficult to identify patients who would benefit from TACE. Often the delivered drug does not penetrate sufficiently selectively and deeply into the tumour and the drug delivery system is not releasing the drug at an optimal clinical rate. In addition, therapeutic effectiveness is limited by the crosstalk between the tumour cells and components of the cirrhotic tumour microenvironment. To improve this widely used treatment of one of our most common and deadly cancers, we need to better understand the complex interactions between drug delivery, local pharmacology, tumour targeting mechanisms, liver pathophysiology, patient and tumour heterogeneity, and resistance mechanisms. This review provides a novel and important overview of clinical data and discusses the role of the tumour microenvironment and lymphatic system in the cirrhotic liver, its potential response to TACE, and current and possible novel DDSs for locoregional treatment.

New frontiers in liver ultrasound: From mono to multi parametricity

Modern liver ultrasonography (US) has become a “one-stop shop” able to provide not only anatomic and morphologic but also functional information about vascularity, stiffness and other various liver tissue properties. Modern US techniques allow a quantitative assessment of various liver diseases. US scanning is no more limited to the visualized plane, but three-dimensional, volumetric acquisition and consequent post-processing are also possible. Further, US scan can be consistently merged and visualized in real time with Computed Tomography and Magnetic Resonance Imaging examinations. Effective and safe microbubble-based contrast agents allow a real time, dynamic study of contrast kinetic for the detection and characterization of focal liver lesions. Ultrasound can be used to guide loco-regional treatment of liver malignancies and to assess tumoral response either to interventional procedures or medical therapies. Microbubbles may also carry and deliver drugs under ultrasound exposure. US plays a crucial role in diagnosing, treating and monitoring focal and diffuse liver disease. On the basis of personal experience and literature data, this paper is aimed to review the main topics involving recent advances in the field of liver ultrasound.

Use of X-Ray Fluorescence Microscopy for Studies on Research Models of Hepatocellular Carcinoma

Introduction: TheraSphere^® microspheres containing yttrium ⁹⁰Y are among many radioembolization agents used clinically to reduce liver tumor burden, and their effects on cancer volume reduction are well-established. At the same time, concerns about off target tissue injury often limit their use. Deeper investigation into tissue distribution and long-term impact of these microspheres could inform us about additional ways to use them in practice.

Methods: Healthy rat liver and rabbit liver tumor samples from animals treated with TheraSpheres were sectioned and their elemental maps were generated by X-ray fluorescence microscopy (XFM) at the Advanced Photon Source (APS) synchrotron at Argonne National Laboratory (ANL).

Results: Elemental imaging allowed us to identify the presence and distribution of TheraSpheres in animal tissues without the need for additional sample manipulation or staining. Ionizing radiation produced by ⁹⁰Y radioactive contaminants present in these microspheres makes processing TheraSphere treated samples complex. Accumulation of microspheres in macrophages was observed.

Conclusions: This is the first study that used XFM to evaluate the location of microspheres and radionuclides in animal liver and tumor samples introduced through radioembolization. XFM has shown promise in expanding our understanding of radioembolization and could be used for investigation of human patient samples in the future.