Ablative Focused Ultrasound Synergistically Enhances Thermally Triggered Chemotherapy for Prostate Cancer in Vitro

Studies of Anticancer Activities In Vitro and In Vivo for Butyltin(IV)-Iridium(III) Imidazole-Phenanthroline Complexes with Aggregation-Induced Emission Properties

Organotin(IV) and iridium(III) complexes have shown good application potential in the field of anticancer; however, the aggregation-caused quenching (ACQ) effect induced by high concentration or dose has limited the research on their targeting and anticancer mechanism. Then, a series of aggregation-induced emission (AIE)-activated butyltin(IV)-iridium(III) imidazole-phenanthroline complexes were prepared in this study. Complexes exhibited significant fluorescence improvement in the aggregated state because of the restricted intramolecular rotation (RIR), accompanied by an absolute fluorescence quantum yield of up to 29.2% (IrSn9). Complexes demonstrated potential in vitro antiproliferative and antimigration activity against A549 cells, following a lysosomal-mitochondrial apoptotic pathway. Nude mouse models further confirmed that complexes had favorable in vivo antitumor and antimigration activity in comparison to cisplatin. Therefore, butyltin(IV)-iridium(III) imidazole-phenanthroline complexes possess the potential as potential substitutes for platinum-based drugs.

Combination of chemotherapy and focused ultrasound for the treatment of unresectable pancreatic cancer: a proof-of-concept study

OBJECTIVES

To investigate the safety and preliminary efficacy of the combined treatment of focused ultrasound (FUS) and chemotherapy (nab-paclitaxel plus gemcitabine, nPac/Gem) for patients with unresectable pancreatic cancer.

METHODS

Patients pathologically diagnosed with unresectable pancreatic cancer were included. Low (Isppa = 1.5 kW/cm²), intermediate (2.0 kW/cm²), and high (2.5 kW/cm²) FUS intensity treatment groups were predefined. A 1% duty cycle and the 3+3 scheme were used. Six combined treatments were performed, and adverse events were assessed. Changes in tumor size and tumor response, CA 19-9 level, and patient-reported outcomes at the immediate follow-up (F/U) and/or at the 3-month F/U and survival were evaluated.

RESULTS

Three participants were enrolled in each intensity group. No adverse device effect or dose-limiting toxicity occurred in any of the participants. Seven of the nine participants experienced a >15% tumor size decrease at the immediate F/U CT and at the 3-month F/U CT. The CA 19-9 level decreased in all of the participants at the immediate F/U. All participants in the intermediate-intensity treatment group showed a > 30% tumor size decrease, partial response, and a significant decrease in the CA 19-9 level at 3-month F/U and longer survival (p < 0.05).

CONCLUSION

FUS with an intensity of 1.5 to 2.5 kW/cm² was safe in the combined treatment of FUS and nPac/Gem. Considering the results of the change in tumor size, the change in CA 19-9 level, tumor response, and survival, these FUS parameters can be used for subsequent clinical trials.

KEY POINTS

• No adverse device effect or dose-limiting toxicity occurred in any of the participants when focused ultrasound with an intensity of 1.5-2.5 kW/cm² and a low duty cycle of 1% was combined with chemotherapy. • The intermediate-intensity group showed a >30% tumor size decrease, partial response, and a significant decrease in CA 19-9 in all of the participants at the 3-month follow-up and the longest survival. • Any focused ultrasound setting used in this study could be safe and optimal for subsequent clinical trials.

Synergetic Thermal Therapy for Cancer: State-of-the-Art and the Future

As a safe and minimal-invasive modality, thermal therapy has become an effective treatment in cancer treatment. Other than killing the tumor cells or destroying the tumor entirely, the thermal modality results in profound molecular, cellular and biological effects on both the targeted tissue, surrounding environments, and even the whole body, which has triggered the combination of the thermal therapy with other traditional therapies as chemotherapy and radiation therapy or new therapies like immunotherapy, gene therapy, etc. The combined treatments have shown encouraging therapeutic effects both in research and clinic. In this review, we have summarized the outcomes of the existing synergistic therapies, the underlying mechanisms that lead to these improvements, and the latest research in the past five years. Limitations and future directions of synergistic thermal therapy are also discussed.

Combinatorial approaches of nanotherapeutics for inflammatory pathway targeted therapy of prostate cancer

Prostate cancer (PC) is the most prevalent male urogenital cancer worldwide. PC patients presenting an advanced or metastatic cancer succumb to the disease, even after therapeutic interventions including radiotherapy, surgery, androgen deprivation therapy (ADT), and chemotherapy. One of the hallmarks of PC is evading immune surveillance and chronic inflammation, which is a major challenge towards designing effective therapeutic formulations against PC. Chronic inflammation in PC is often characterized by tumor microenvironment alterations, epithelial-mesenchymal transition and extracellular matrix modifications. The inflammatory events are modulated by reactive nitrogen and oxygen species, inflammatory cytokines and chemokines. Major signaling pathways in PC includes androgen receptor, PI3K and NF-κB pathways and targeting these inter-linked pathways poses a major therapeutic challenge. Notably, many conventional treatments are clinically unsuccessful, due to lack of targetability and poor bioavailability of the therapeutics, untoward toxicity and multidrug resistance. The past decade witnessed an advancement of nanotechnology as an excellent therapeutic paradigm for PC therapy. Modern nanovectorization strategies such as stimuli-responsive and active PC targeting carriers offer controlled release patterns and superior anti-cancer effects. The current review initially describes the classification, inflammatory triggers and major inflammatory pathways of PC, various PC treatment strategies and their limitations. Subsequently, recent advancement in combinatorial nanotherapeutic approaches, which target PC inflammatory pathways, and the mechanism of action are discussed. Besides, the current clinical status and prospects of PC homing nanovectorization, and major challenges to be addressed towards the advancement PC therapy are also addressed.

Pre-Exposure to Stress-Inducing Agents Increase the Anticancer Efficacy of Focused Ultrasound against Aggressive Prostate Cancer Cells

Despite the initial success in treatment of localized prostate cancer (PCa) using surgery, radiation or hormonal therapy, recurrence of aggressive tumors dictates morbidity and mortality. Focused ultrasound (FUS) is being tested as a targeted, noninvasive approach to eliminate the localized PCa foci, and strategies to enhance the anticancer potential of FUS have a high translational value. Since aggressive cancer cells utilize oxidative stress (Ox-stress) and endoplasmic reticulum stress (ER-stress) pathways for their survival and recurrence, we hypothesized that pre-treatment with drugs that disrupt stress-signaling pathways in tumor cells may increase FUS efficacy. Using four different PCa cell lines, i.e., LNCaP, C4-2B, 22Rv1 and DU145, we tested the in vitro effects of FUS, alone and in combination with two clinically tested drugs that increase Ox-stress (i.e., CDDO-me) or ER-stress (i.e., nelfinavir). As compared to standalone FUS, significant (p < 0.05) suppressions in both survival and recurrence of PCa cells were observed following pre-sensitization with low-dose CDDO-me (100 nM) and/or nelfinavir (2 µM). In drug pre-sensitized cells, significant anticancer effects were evident at a FUS intensity of as low as 0.7 kW/cm². This combined mechanochemical disruption (MCD) approach decreased cell proliferation, migration and clonogenic ability and increased apoptosis/necrosis and reactive oxygen species (ROS) production. Furthermore, although activated in cells that survived standalone FUS, pre-sensitization with CDDO-me and/or nelfinavir suppressed both total and activated (phosphorylated) NF-κB and Akt protein levels. Thus, a combined MCD therapy may be a safe and effective approach towards the targeted elimination of aggressive PCa cells.

Low intensity focused ultrasound responsive microcapsules for non-ablative ultrafast intracellular release of small molecules

Focused ultrasound (FU) is in demand for clinical cancer therapy, but the possible thermal injury to the normal peripheral tissues limits the usage of the ablative FU for tumors with a large size; therefore research efforts have been made to minimize the possible side effects induced by the FU treatment. Non-ablative focused ultrasound assisted chemotherapy could open a new avenue for the development of cancer therapy technology. Here, low intensity focused ultrasound (LIFU) for controlled quick intracellular release of small molecules (Mw ≤ 1000 Da) without acute cell damage is demonstrated. The release is achieved by a composite poly(allylamine hydrochloride) (PAH)/poly-(sodium 4-styrenesulfonate) (PSS)/SiO2 microcapsules which are highly sensitive to LIFU and can be effectively broken by weak cavitation effects. Most PAH/PSS/SiO2 capsules in B50 rat neuronal cells can be ruptured and release rhodamine B (Rh-B) into the cytosol within only 30 s of 0.75 W cm-2 LIFU treatment, as demonstrated by the CLSM results. While the same LIFU treatment shows no obvious damage to cells, as proved by the live/dead experiment, showing that 90% of cells remain alive.

Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy

This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.

Phenotypic alterations in liver cancer cells induced by mechanochemical disruption

Hepatocellular carcinoma (HCC) is a highly fatal disease recognized as a growing global health crisis worldwide. Currently, no curative treatment is available for early-to-intermediate stage HCC, characterized by large and/or multifocal tumors. If left untreated, HCC rapidly progresses to a lethal stage due to favorable conditions for metastatic spread. Mechanochemical disruption of cellular structures can potentially induce phenotypic alterations in surviving tumor cells that prevent HCC progression. In this paper, HCC response to mechanical vibration via high-intensity focused ultrasound and a chemical disruptive agent (ethanol) was examined in vitro and in vivo. Our analysis revealed that mechanochemical disruption caused a significant overproduction of reactive oxygen species (ROS) in multiple HCC cell lines (HepG2, PLC/PRF/5, and Hep3B). This led to a decrease in cell viability and long-term proliferation due to increased expression and activity of death receptors TNFR1 and Fas. The cells that survived mechanochemical disruption had a reduced expression of cancer stem cell markers (CD133, CD90, CD49f) and a diminished colony-forming ability. Mechanochemical disruption also impeded HCC migration and their adhesion to vascular endothelium, two critical processes in hematogenous metastasis. The HCC transformation to a non-tumorigenic phenotype post mechanochemical disruption was confirmed by a lack of tumor spheroid formation in vitro and complete tumor regression in vivo. These results show that mechanochemical disruption inhibits uncontrolled proliferation and reduces tumorigenicity and aggressiveness of HCC cells through ROS overproduction and associated activation of TNF- and Fas-mediated cell death signaling. Our study identifies a novel curative therapeutic approach that can prevent the development of aggressive HCC phenotypes.

Amphiphilic Polypeptoids Rupture Vesicle Bilayers To Form Peptoid-Lipid Fragments Effective in Enhancing Hydrophobic Drug Delivery

Peptoids are highly biocompatible pseudopeptidic polyglycines with designable substituents on the nitrogen atoms. The therapeutic and drug-carrying potential of these materials requires a fundamental understanding of their interactions with lipid bilayers. In this work, we use amphiphilic polypeptoids with up to 100 monomeric units where a significant fraction (26%) of the nitrogen atoms are functionalized with decyl groups (hydrophobes) that insert into the lipid bilayer through the hydrophobic effect. These hydrophobically modified polypeptoids (HMPs) insert their hydrophobes into lipid bilayers creating instabilities that lead to the rupture of vesicles. At low HMP concentrations, such rupture leads to the creation of large fragments which remarkably anchor to intact vesicles through the hydrophobic effect. At high HMP concentrations, all vesicles rupture to smaller HMP-lipid fragments of the order of 10 nm. We show that the technique for such nanoscale polymer-lipid fragments can be exploited to sustain highly hydrophobic drug species in solution. Using the kinase inhibitor, Sorafenib as a model drug, it is shown that HMP-lipid fragments containing the drug can efficiently enter a hepatocellular carcinoma cell line (Huh 7.5), indicating the use of such fragments as drug delivery nanocarriers.

Deciphering the Peculiar Behavior of β-Lapachone in Lipid Monolayers and Bilayers

β-Lapachone (β-Lap) is a promising anticancer drug whose applications have been limited so far because of its poor solubility and stability. Its encapsulation in liposomes has been proposed to overcome these issues. However, surface pressure measurements show that β-Lap exhibits atypical interfacial behavior when mixed with lipids. Although the drug does not seem to be retained in lipid monolayers as deduced from the π-A isotherms, small changes in compressibility moduli suggest that β-Lap actually interacts with lipids, either disorganizing or rigidifying their monolayers. Thermal and structural analyses of lipid bilayers confirm the existence of β-Lap/lipid interactions and show that the drug inserts between hydrophobic chains, close to the polar headgroup in DPPC bilayers and deeper in the acyl chains in POPC bilayers. Molecular dynamics simulations allow a comprehensive description of the drug position and orientation in DOPC and POPC bilayers in the presence or absence of cholesterol.

Engineering temperature-sensitive plateletsomes as a tailored chemotherapy platform in combination with HIFU ablation for cancer treatment

Chemotherapy is widely used in combination with high-intensity focused ultrasound (HIFU) ablation for cancer therapy; however, the spatial and temporal integration of chemotherapy and HIFU ablation remains a challenge. Here, temperature-sensitive plateletsomes (TSPs) composed of platelet (PLT) membrane, 1-stearoyl-2-hydroxy-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine were developed to adequately integrate chemotherapy with HIFU tumor ablation in vivo.

Methods: The thermosensitive permeability of TSPs was evaluated under both water bath heating and HIFU hyperthermia. The targeting performance, pharmacokinetic behavior and therapeutic potential of TSPs in combination with HIFU ablation were evaluated using HeLa cells and a HeLa cell tumor-bearing nude mouse model in comparison with temperature-sensitive liposomes (TSLs).

Results: TSPs showed high drug loading efficiency and temperature-sensitive permeability. When applied in vivo, TSPs showed a circulation lifetime comparable to that of TSLs and exhibited PLT-specific cancer cell affinity and a vascular damage response. Upon HIFU hyperthermia, TSPs displayed ultrafast drug release and enhanced tumor uptake, providing high drug availability in the tumor site to cooperate with HIFU ablation. After HIFU ablation, TSPs rapidly targeted the postoperative tumor site by adhesion to the damaged tumor vasculature, leading to targeted and localized postoperative chemotherapy.

Conclusion: Due to effective integration at both intraoperative and postoperative stages, TSPs could be a promising chemotherapy nanoplatform in combination with HIFU ablation for cancer therapy.

Mechanochemical Disruption Suppresses Metastatic Phenotype and Pushes Prostate Cancer Cells toward Apoptosis

Chemical-based medicine that targets specific oncogenes or proteins often leads to cancer recurrence due to tumor heterogeneity and development of chemoresistance. This challenge can be overcome by mechanochemical disruption of cancer cells via focused ultrasound (FUS) and sensitizing chemical agents such as ethanol. We demonstrate that this disruptive therapy decreases the viability, proliferation rate, tumorigenicity, endothelial adhesion, and migratory ability of prostate cancer cells in vitro. It sensitized the cells to TNFR1-- and Fas--mediated apoptosis and reduced the expression of metastatic markers CD44 and CD29. Using a prostate cancer xenograft model, we observed that the mechanochemical disruption led to complete tumor regression in vivo. This switch to a nonaggressive cell phenotype was caused by ROS and Hsp70 overproduction and subsequent impairment of NFκB signaling. FUS induces mechanical perturbations of diverse cancer cell populations, and its combination with agents that amplify and guide remedial cellular responses can stop lethal cancer progression. IMPLICATIONS: Mechanochemical disruption therapy in which FUS is combined with ethanol can be curative for locally aggressive and castration-resistant prostate cancer.

Clusters of Nanoscale Liposomes Modulate the Release of Encapsulated Species and Mimic the Compartmentalization Intrinsic in Cell Structures

We report the ability to place a high concentration of liposomes in a confined volume as a multicompartment cluster that mimics biological cells and allows for the modulation of release of encapsulated species. The formation of these coated multicompartmental structures is achieved by first binding liposomes into clusters before encapsulating them within a two-dimensional metal-organic framework composed of tannic acid coordinated with a metal ion. The essential feature is a molecularly thin skin over a ssystem of clustered liposomes in a pouch. The structural features of these pouches are revealed by small-angle scattering and electron microscopy. Through cryogenic electron microscopy, clusters with intact liposomes are observed that appear to be encapsulated within a pouch. Small-angle X-ray scattering shows the emergence of a relatively weak Bragg peak at q = 0.125 Å^-1, possibly indicating the attachment of the bilayers of adjacent liposomes. The metal-phenolic network (MPN) forms a nanosized conformal coating around liposome clusters, resulting in the reduced release rate of the encapsulated rhodamine B dye. We further show the possibility of communication between the adjacent nanocompartments in the cluster by demonstrating enhanced energy transfer using fluorescence resonance energy transfer (FRET) experiments where the lipophilic donor dye 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO) incorporated within one liposomal compartment transfers energy upon excitation to the lipophilic acceptor dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) in a neighboring liposomal compartment due to their close proximity within the multicompartmental cluster. These observations have significance in adapting these multicompartmental structures that mimic biological cells for cascade reactions and as new depot drug delivery systems.

Porphyrin–ferrocene conjugates for photodynamic and chemodynamic therapy

Porphyrin–ferrocene conjugates were designed and synthesized for photodynamic and chemodynamic therapy.

Focused Ultrasound-Triggered Release of Tyrosine Kinase Inhibitor From Thermosensitive Liposomes for Treatment of Renal Cell Carcinoma

This study reports, for the first time, development of tyrosine kinase inhibitor-loaded, thermosensitive liposomes (TKI/TSLs) and their efficacy for treatment of renal cell carcinoma when triggered by focused ultrasound (FUS). Uptake of these nanoparticles into renal cancer cells was visualized with confocal and fluorescent imaging of rhodamine B-loaded liposomes. The combination of TKI/TSLs and FUS was tested in an in vitro tumor model of renal cell carcinoma. According to MTT cytotoxic assay and flow cytometric analysis, the combined treatment led to the least viability (23.4% ± 2.49%, p < 0.001), significantly lower than that observed from treatment with FUS (97.6% ± 0.67%, not significant) or TKI/TSL (71.0% ± 3.65%, p < 0.001) at 96 h compared to control. The importance of this unique, synergistic combination was demonstrated in viability experiments with non-thermosensitive liposomes (TKI/NTSL + FUS: 58.8% ± 1.5% vs. TKI/TSL + FUS: 36.2% ± 1.4%, p < 0.001) and heated water immersion (TKI/TSL + WB43°: 59.3% ± 2.91% vs. TKI/TSL + FUS: 36.4% ± 1.55%, p < 0.001). Our findings coupled with the existing use of FUS in clinical practice make the proposed combination of targeted chemotherapy, nanotechnology, and FUS a promising platform for enhanced drug delivery and cancer treatment.