Antitumor Effects of Intra-Arterial Delivery of Albumin-Doxorubicin Nanoparticle Conjugated Microbubbles Combined with Ultrasound-Targeted Microbubble Activation on VX2 Rabbit Liver Tumors

The recent advancements in protein nanoparticles for immunotherapy

In recent years, the advancement of nanoparticle-based immunotherapy has introduced an innovative strategy for combatting diseases. Compared with other types of nanoparticles, protein nanoparticles have obtained substantial attention owing to their remarkable biocompatibility, biodegradability, ease of modification, and finely designed spatial structures. Nature provides several protein nanoparticle platforms, including viral capsids, ferritin, and albumin, which hold significant potential for disease treatment. These naturally occurring protein nanoparticles not only serve as effective drug delivery platforms but also augment antigen delivery and targeting capabilities through techniques like genetic modification and covalent conjugation. Motivated by nature's originality and driven by progress in computational methodologies, scientists have crafted numerous protein nanoparticles with intricate assembly structures, showing significant potential in the development of multivalent vaccines. Consequently, both naturally occurring and de novo designed protein nanoparticles are anticipated to enhance the effectiveness of immunotherapy. This review consolidates the advancements in protein nanoparticles for immunotherapy across diseases including cancer and other diseases like influenza, pneumonia, and hepatitis.

Delivery of Anticancer Drugs Using Microbubble-Assisted Ultrasound in a 3D Spheroid Model

Tumor spheroids are promising three-dimensional (3D) in vitro tumor models for the evaluation of drug delivery methods. The design of noninvasive and targeted drug methods is required to improve the intratumoral bioavailability of chemotherapeutic drugs and reduce their adverse off-target effects. Among such methods, microbubble-assisted ultrasound (MB-assisted US) is an innovative modality for noninvasive targeted drug delivery. The aim of the present study is to evaluate the efficacy of this US modality for the delivery of bleomycin, doxorubicin, and irinotecan in colorectal cancer (CRC) spheroids. MB-assisted US permeabilized the CRC spheroids to propidium iodide, which was used as a drug model without affecting their growth and viability. Histological analysis and electron microscopy revealed that MB-assisted US affected only the peripheral layer of the CRC spheroids. The acoustically mediated bleomycin delivery induced a significant decrease in CRC spheroid growth in comparison to spheroids treated with bleomycin alone. However, this US modality did not improve the therapeutic efficacy of doxorubicin and irinotecan on CRC spheroids. In conclusion, this study demonstrates that tumor spheroids are a relevant approach to evaluate the efficacy of MB-assisted US for the delivery of chemotherapeutics.

Radioiodine-131-Labeled Theranostic Nanoparticles for Transarterial Radioembolization and Chemoembolization Combination Therapy of VX2 Liver Tumor

In interventional treatment, materials are administered into the blood supply artery and directly delivered to tumors, offering proper scenarios for nanomedicine potential clinical applications. Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are effective treatment methods for hepatocellular carcinoma (HCC), but postoperative residual tumor may result in intrahepatic recurrence and distant metastasis. The combination therapy of TACE and TARE based on multifunctional nanoparticles (NPs) is expected to overcome the drug resistance in hypoxic tumors and improve the therapeutic effect. Herein, BaGdF5 NPs are synthesized and then coated with polydopamine (PDA), conjugated with the chemotherapeutic drug cis-diamminedichloride platinum (CDDP), radio-labeled with therapeutic radionuclide 131 I, yielding 131 I-BaGdF5 @PDA-CDDP NPs. The in vitro anti-cancer effects of 131 I-BaGdF5 @PDA-CDDP NPs are confirmed using CCK-8 and γ-H2AX assays in Huh7 cells. Mixed with Lipiodol, 131 I-BaGdF5 @PDA-CDDP NPs are injected into the hepatic artery via a microcatheter to realize the TACE and TARE combination therapy in a rabbit VX2 liver tumor model. The results indicate that glucose metabolism is clearly decreased based on 18 F-FDG PET imaging and the apoptosis of tumor cells is increased. Furthermore, 131 I and BaGdF5 NPs can be used for SPECT imaging and CT/MR imaging respectively, facilitating real-time monitoring of the in vivo biodistribution of 131 I-BaGdF5 @PDA-CDDP NPs.

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.

Olaparib@human serum albumin nanoparticles as sustained drug-releasing tumor-targeting nanomedicine to inhibit growth and metastasis in the mouse model of triple-negative breast cancer

Poly(ADP-ribose) polymerase inhibitor olaparib demonstrated therapeutic effectiveness in highly metastatic triple-negative breast cancer (TNBC). However, olaparib offers a weak therapeutic response in wild-type BRCA cancers due to the drug's poor bioavailability. Here, a bioinspired/active-tumor targeted nanoparticles system of human serum albumin with physical entrapment of olaparib was prepared via a low-energy desolvation technique using the crosslinker glutaraldehyde. The developed OLA@HSA NPs were nanosize (∼140 nm), kinetically stable with a low polydispersity (0.3), exhibited olaparib entrapment (EE 76.01 ± 2.53%, DL 6.76 ± 0.22%), and sustained drug release at pH 7.4 with an enhancement of drug release in acidic pH. OLA@HSA NPs decreased the half-maximal inhibitory concentrations (IC₅₀) of olaparib by 1.6, 1.8-fold in 24 h and 2.2, 2.4 folds in 48 h for human (MDA-MB 231) and mouse (4T1) TNBC cells, respectively, mediated by their enhanced time-dependent cellular uptake than free olaparib. The OLA@HSA-OA NPs induced concentration-dependent phosphatidylserine (apoptotic marker) externalization and arrested the cell population in the G2/M phase in both the tested cell lines at a higher level than free olaparib. The NPs formulation increased DNA fragmentation, mitochondrial membrane depolarization, and ROS generation than the free olaparib. The in vivo study conducted using 4T1-Luc tumor-bearing mice demonstrated strong tumor growth inhibitory potential of OLA@HSA NPs by elevating apoptosis ROS generation and reducing the level of the antiproliferative marker, Ki-67. OLA@HSA NPs reduced the occurrence of lung metastasis (formation of metastasis nodules decreased by ∼10 fold). OLA@HSA NPs could be a promising nanomedicine for the TNBC treatment.

Delivery of anti-cancer drugs using microbubble-assisted ultrasound in digestive oncology: From preclinical to clinical studies

INTRODUCTION

The combination of microbubbles (MBs) and ultrasound (US) is an emerging method for the noninvasive and targeted enhancement of intratumor chemotherapeutic uptake. This method showed an increased local drug extravasation in tumor tissue while reducing the systemic adverse effects in various tumor models.

AREA COVERED

We focused on preclinical and clinical studies investigating the therapeutic efficacy and safety of this technology for the treatment of colorectal, pancreatic and liver cancers. We discussed the limitations of the current investigations and future perspectives.

EXPERT OPINION

The therapeutic efficacy and the safety of delivery of standard chemotherapy regimen using MB-assisted US have been mainly demonstrated in subcutaneous models of digestive cancers. Although some clinical trials on pancreatic ductal carcinoma and hepatic metastases from various digestive cancers have shown promising results, successful evaluation of this method in terms of US settings, chemotherapeutic schemes and MBs-related parameters will need to be addressed in more relevant preclinical models of digestive cancers, in small and large animals before fully and successfully translating this technology for clinic use. Ultimately, a clear evidence of the correlation between the enhanced intratumoral concentrations of therapeutics and the increased therapeutic response of tumors have to be provided in clinical trials.

Early Assessment of Response to Radiofrequency Ablation With CT Perfusion Imaging in Rabbit VX2 Liver Tumor Model

Objectives

To discriminate viable tumors from benign periablational enhancement (BPE) in early stage after radiofrequency ablation (RFA) is a major confounding problem. The goal of this study is to evaluate quantitative assessment and diagnostic value of CT perfusion between viable tumors and BPE after RFA in the rabbit liver VX2 tumor model, with pathological results as the standard.

Methods

Twenty-eight VX2 liver tumors were treated with RFA, on days 1, 3, 7, and 14, seven rabbits were randomly chosen for CT perfusion and performed pathology examinations immediately. The perfusion parameters along with the profile of time-density curves (TDCs) and pseudo-color images of the parameters were observed in both BPE and viable tumors, then compared with the pathology results. The perfusion parameters included blood flow (BF), blood volume (BV), time to peak (TTP), permeability (P), arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI).

Results

A total of 26/28 rabbits successfully underwent CT perfusion, while 6/26 lesions were confirmed to be viable tumors. The TDCs of BPE were mainly speed-up platform curves (15/26), while the viable tumors showed mainly speed-up speed-down (3/6) and speed-up platform (2/6) curves. The PVP values were significantly higher, and the HPI values were significantly lower for BPE at all time points than viable tumors (P < 0.05). Both of PVP value and HPI value have high efficiency for the differential diagnosis of the viable tumors and BPE at each time point. These characteristics of CT perfusion parameters were consistent with pathological changes.

Conclusions

The TDCs, PVP and HPI have the potential to indicate BPE and viable tumors effectively early after RFA treatment, the results were highly consistent with pathology. CT perfusion has advantages with great efficacy in monitoring the therapeutic effect early after RFA treatment.

Brain Delivery of Curcumin Through Low-Intensity Ultrasound-Induced Blood-Brain Barrier Opening via Lipid-PLGA Nanobubbles

Background

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Owing to the presence of blood-brain barrier (BBB), conventional pharmaceutical agents are difficult to the diseased nuclei and exert their action to inhibit or delay the progress of PD. Recent literatures have demonstrated that curcumin shows the great potential to treat PD. However, its applications are still difficult in vivo due to its poor druggability and low bioavailability through the BBB.

Methods

Melt-crystallization methods were used to improve the solubility of curcumin, and curcumin-loaded lipid-PLGA nanobubbles (Cur-NBs) were fabricated through encapsulating the curcumin into the cavity of lipid-PLGA nanobubbles. The bubble size, zeta potentials, ultrasound imaging capability and drug encapsulation efficiency of the Cur-NBs were characterized by a series of analytical methods. Low-intensity focused ultrasound (LIFU) combined with Cur-NB was used to open the BBB to facilitate curcumin delivery into the deep brain of PD mice, followed by behavioral evaluation for the treatment efficacy.

Results

The solubility of curcumin was improved by melt-crystallization methods, with 2627-fold higher than pure curcumin. The resulting Cur-NBs have a nanoscale size about 400 nm and show excellent contrast imaging performance. Curcumin drugs encapsulated into Cur-NBs could be effectively released when Cur-NBs were irradiated by LIFU at the optimized acoustic pressure, achieving 30% cumulative release rate within 6 h. Importantly, Cur-NBs combined with LIFU can open the BBB and locally deliver the curcumin into the deep-seated brain nuclei, significantly enhancing efficacy of curcumin in the Parkinson C57BL/6J mice model in comparison with only Cur-NBs and LIFU groups.

Conclusion

In this work, we greatly improved the solubility of curcumin and developed Cur-NBs for brain delivery of curcumin against PD through combining with LIFU-mediating BBB. Cur-NBs provide a platform for these potential drugs which are difficult to cross the BBB to treat PD disease or other central nervous system (CNS) diseases.

The Uniqueness of Albumin as a Carrier in Nanodrug Delivery

Albumin is an appealing carrier in nanomedicine because of its unique features. First, it is the most abundant protein in plasma, endowing high biocompatibility, biodegradability, nonimmunogenicity, and safety for its clinical application. Second, albumin chemical structure and conformation allows interaction with many different drugs, potentially protecting them from elimination and metabolism in vivo, thus improving their pharmacokinetic properties. Finally, albumin can interact with receptors overexpressed in many diseased tissues and cells, providing a unique feature for active targeting of the disease site without the addition of specific ligands to the nanocarrier. For this reason, albumin, characterized by an extended serum half-life of around 19 days, has the potential of promoting half-life extension and targeted delivery of drugs. Therefore, this article focuses on the importance of albumin as a nanodrug delivery carrier for hydrophobic drugs, taking advantage of the passive as well as active targeting potential of this nanocarrier. Particular attention is paid to the breakthrough NAB-Technology, with emphasis on the advantages of Nab-Paclitaxel (Abraxane), compared to the solvent-based formulations of Paclitaxel, i.e., CrEL-paclitaxel (Taxol) in a clinical setting. Finally, the role of albumin in carrying anticancer compounds is depicted, with a particular focus on the albumin-based formulations that are currently undergoing clinical trials. The article sheds light on the power of an endogenous substance, such as albumin, as a drug delivery system, signifies the importance of the drug vehicle in drug performance in the biological systems, and highlights the possible future trends in the use of this drug delivery system.

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

Transarterial chemoembolization (TACE) is an image-guided locoregional therapy used for the treatment of patients with primary or secondary liver cancer. However, conventional TACE formulations are rapidly dissociated due to the instability of the emulsion, resulting in insufficient local drug concentrations in the target tumor.

Methods: To overcome these limitations, a doxorubicin-loaded albumin nanoparticle-conjugated microbubble complex in an iodized oil emulsion (DOX-NPs-MB complex in Lipiodol) has been developed as a new ultrasound-triggered TACE formulation.

Results: (1) Microbubbles enhanced therapeutic efficacy by effectively delivering doxorubicin- loaded nanoparticles into liver tumors via sonoporation under ultrasound irradiation (US+). (2) Microbubbles constituting the complex retained their function as an ultrasound contrast agent in Lipiodol. In a rabbit VX2 liver cancer model, the in vivo study of DOX-NPs-MB complex in Lipiodol (US+) decreased the viability of tumor more than the conventional TACE formulation, and in particular, effectively killed cancer cells in the tumor periphery.

Conclusion: Incorporation of doxorubicin-loaded microbubble in the TACE formulation facilitated drug delivery to the tumor with real-time monitoring and enhanced the therapeutic efficacy of TACE. Thus, the enhanced TACE formulation may represent a new treatment strategy against liver cancer.

Combined treatment of sorafenib and doxorubicin-loaded microbubble-albumin nanoparticle complex for hepatocellular carcinoma: A feasibility study

Purpose

To assess the feasibility of the combined sorafenib (SOR) and doxorubicin-loaded microbubble-albumin nanoparticle complex (DOX-MAC) treatment effect in an orthotopic rat model of hepatocellular carcinoma (HCC).

Materials and methods

Sixty-two rats with N1-S1 hepatoma were divided into four groups according to the treatment methods, i.e. G1 (SOR and DOX-MAC; n = 12), G2 (SOR; n = 15), G3 (DOX-MAC; n = 12), G4 (DOX; n = 11), and G5 (normal saline; n = 12). We performed the theragnostic, contrast-enhanced ultrasound examination and treatment at the baseline, one-week, and two-weeks. Tumor volume and perfusion parameters were compared at each time point and the differences between all of the groups over time were analyzed using repeated measures ANOVA. We also analyzed the apoptotic index and microvessel density (MVD) per each tumor specimen in all of the groups.

Results

The tumors increased from the beginning in all of the groups to the final follow-up, whereas the tumor growth in the G1 group and the G2 group was inhibited during the treatment period compared to the baseline tumor volume (P = 0.016 and P = 0.031). The G1 group resulted in tumor growth inhibition compared to the control group (P = 0.008). The G1 group showed that the peak enhancement and wash-in area under the curve were lower than that of the G4 group (P = 0.010 and 0.022). However, there was no difference in perfusion parameters in the other treated group compared to control group. The MVD of the G1 group tumor was lower than that of the G4 group (P = .016).

Conclusion

Our results suggest that the combination therapy of SOR and DOX-MAC can cause inhibition of tumor growth after treatment and that this therapy can be adequately monitored using the theragnostic DOX-MAC agent.

Ultrasound Assisted a Peroxisome Proliferator-Activated Receptor (PPAR)γ Agonist-Loaded Nanoparticle-Microbubble Complex to Attenuate Renal Interstitial Fibrosis

Objective

To investigate the antifibrotic effect of the combination of a PPARγ agonist-loaded nanoparticle-microbubble complex with ultrasound (US) exposure on renal interstitial fibrosis (RIF).

Materials and Methods

Polylactide-co-glycolide (PLGA) nanoparticles were used to load PPARγ agonist (rosiglitazone, RSG) and prepare PLGA-RSG nanoparticles (PLNPs-RSG); then, a novel complex between PLNPs-RSG and SonoVue microbubbles (MBs) (PLNPs-RSG-MBs) was prepared. The size distribution, zeta potentials, RSG-loading capacity and entrapment efficiency were measured, and the release of RSG was assessed using a UV-vis spectrophotometer. The in vitro cytotoxicity and in vivo systemic toxicity assays were performed. The cellular uptake assessment was performed using a confocal laser scanning microscope (CLSM). The in vivo biodistribution assessment was performed using fluorescence imaging with a near-infrared (NIR) imaging system. Furthermore, this complex was administered to a unilateral ureteral obstruction (UUO) rat model with the assistance of US exposure to investigate the antifibrotic effect.

Results

This PLNPs-RSG-MBs complex had a size of 2199.5± 988.1 nm and a drug-loading efficiency of 28.5%. In vitro cytotoxicity and in vivo systemic toxicity assays indicated that the PLNPs-RSG-MBs complex displayed excellent biocompatibility. In addition, the complex showed high cellular uptake efficiency in vitro and kidney-targeting ability in vivo. In a UUO rat model, the combination of the PLNPs-RSG-MBs complex with US exposure significantly reduced collagen deposition and successfully attenuated renal fibrosis.

Conclusion

The combination of the PLNPs-RSG-MBs complex with US exposure may be a promising approach for the treatment of RIF.

Cancer Nanomedicine

This Special Issue on Cancer Nanomedicine within Cancers brings together 46 cutting-edge papers covering research within the field along with insightful reviews and opinions reflecting our community [...].

UTMD inhibit EMT of breast cancer through the ROS/miR-200c/ZEB1 axis

As a potential drug/gene delivery system, the ultrasound-targeted microbubble destruction (UTMD) system can be used as a vehicle as well as increasing the permeability of biological barriers to enhance the effect of tumor treatment. However, the effect of UTMD in the tumor EMT process is unknown. In this study, we aimed to investigate the potential and mechanism of UTMD induced oxidative stress in inhibiting EMT of breast cancer. Human breast MDA231 cells were treated with microbubble (MB), ultrasound (US) and UTMD, respectively. The generation of oxidative stress, the levels of miR-200c, ZEB1 and vimentin, and the numbers of migratory cells were evaluated quantitatively and qualitatively by the measurement of intracellular reactive oxygen species (ROS), qRT-PCR, western blot assay, and transwell assay. Then, to evaluate the role of UTMD-induced oxidative stress and miR-200c in the epithelial-mesenchymal transition (EMT) inhibition, the ROS scavenger N-acetyl-L-cysteine (NAC) and miR-200c inhibitor were used before UTMD treatment. We found that UTMD induced oxidative stress, upregulated the expression of miR-200c, downregulated the expression of ZEB1 and vimentin and suppressed the MDA231 cell migration. The addition of NAC and miR-200c inhibitor had an opposite impact on the expression of miR-200c and ZEB1, thus hindered the effects of UTMD on MDA231 cells EMT. In conclusion, UTMD can inhibit the EMT characteristics of MDA231 cells. The mechanism may be related to the regulation of the miR-200c/ZEB1 axis through the generation of ROS induced by UTMD, which may provide a new strategy to prevent the tumor cells EMT under UTMD treatment.

Nanoparticle Drug Delivery Systems for α-Mangostin

α-Mangostin, a xanthone derivative from the pericarp of Garcinia mangostana L., has numerous bioactivities and pharmacological properties. However, α-mangostin has low aqueous solubility and poor target selectivity in the human body. Recently, nanoparticle drug delivery systems have become an excellent technique to improve the physicochemical properties and effectiveness of drugs. Therefore, many efforts have been made to overcome the limitations of α-mangostin through nanoparticle formulations. Our review aimed to summarise and discuss the nanoparticle drug delivery systems for α-mangostin from published papers recorded in Scopus, PubMed and Google Scholar. We examined various types of nanoparticles for α-mangostin to enhance water solubility, provide controlled release and create targeted delivery systems. These forms include polymeric nanoparticles, nanomicelles, liposomes, solid lipid nanoparticles, nanofibers and nanoemulsions. Notably, nanomicelle modification increased α-mangostin solubility increased more than 10,000 fold. Additionally, polymeric nanoparticles provided targeted delivery and significantly enhanced the biodistribution of α-mangostin into specific organs. In conclusion, the nanoparticle drug delivery system could be a promising technique to increase the solubility, selectivity and efficacy of α-mangostin as a new drug candidate in clinical therapy.

Anti-Tumor Drug-Loaded Oxygen Nanobubbles for the Degradation of HIF-1α and the Upregulation of Reactive Oxygen Species in Tumor Cells

Hypoxia is a key concern during the treatment of tumors, and hypoxia-inducible factor 1 alpha (HIF-1α) has been associated with increased tumor resistance to therapeutic modalities. In this study, doxorubicin-loaded oxygen nanobubbles (Dox/ONBs) were synthesized, and the effectiveness of drug delivery to MDA-MB-231 breast cancer and HeLa cells was evaluated. Dox/ONBs were characterized using optical and fluorescence microscopy, and size measurements were performed through nanoparticle tracking analysis (NTA). The working mechanism of Dox was evaluated using reactive oxygen species (ROS) assays, and cellular penetration was assessed with confocal microscopy. Hypoxic conditions were established to assess the effect of Dox/ONBs under hypoxic conditions compared with normoxic conditions. Our results indicate that Dox/ONBs are effective for drug delivery, enhancing oxygen levels, and ROS generation in tumor-derived cell lines.