Smart Shockwave Responsive Titania-Based Nanoparticles for Cancer Treatment

Cutting-edge nanotechnology: unveiling the role of zinc oxide nanoparticles in combating deadly gastrointestinal tumors

Zinc oxide nanoparticles (ZnO-NPs) have gained significant attention in cancer therapy due to their unique physical and chemical properties, particularly in treating gastrointestinal (GI) cancers such as gastric, colorectal, and hepatocellular carcinoma. These nanoparticles generate reactive oxygen species (ROS) upon entering cancer cells, causing oxidative stress that leads to cellular damage, DNA fragmentation, and apoptosis. ZnO-NPs affect the expression of key proteins involved in apoptosis, including p53, Bax, and Bcl-2, which regulate cell cycle arrest and programmed cell death. Additionally, ZnO-NPs can reduce mitochondrial membrane potential, further enhancing apoptosis in cancer cells. Furthermore, ZnO-NPs inhibit cancer cell proliferation by interfering with cell cycle progression. They reduce levels of cyclins and cyclin-dependent kinases (CDKs), leading to cell cycle arrest. ZnO-NPs also exhibit anti-metastatic properties by inhibiting the migration and invasion of cancer cells through modulation of signaling pathways that affect cell adhesion and cytoskeletal dynamics. The efficacy of ZnO-NPs in overcoming chemotherapy resistance has been demonstrated by their ability to reduce the IC50 values of chemotherapeutic agents, making cancer cells more susceptible to drug-induced cell death. In this review, we summarize the mechanisms by which ZnO-NPs exert anticancer effects in GI cancers, focusing on apoptosis, cell cycle regulation, and metastasis inhibition, while also highlighting the current limitations in translating these findings into effective clinical treatments.

Ultrasound-assisted water oxidation: unveiling the role of piezoelectric metal-oxide sonocatalysts for cancer treatment

Ultrasound radiation has been widely used in biomedical application for both diagnosis and therapy. Metal oxides nanoparticles (NPs), like ZnO or TiO2 NPs, have been widely demonstrated to act as excellent sonocatalysts and significantly enhance cavitation at their surface, making them optimal for sonodynamic cancer therapy. These NPs often possess semiconductive and piezoelectric properties that contribute to the complex phenomena occurring at the water-oxide interface during sonostimulation. Despite the great potential in applied sonocatalysis and water splitting, the complex mechanism that governs the phenomenon is still a research subject. This work investigates the role of piezoelectric ZnO micro- and nano-particles in ultrasound-assisted water oxidation. Three metal oxides presenting fundamental electronic and mechanical differences are evaluated in terms of ultrasound-triggered reactive oxygen species generation in aqueous media: electromechanically inert SiO2 NPs, semiconducting TiO2 NPs, piezoelectric and semiconducting ZnO micro- and nanoparticles with different surface areas and sizes. The presence of silver ions in the aqueous solution was further considered to impart a potential electron scavenging effects and better evaluate the oxygen generation performances of the different structures. Following sonoirradiation, the particles are optically and chemically analyzed to study the effect of sonostimulation at their surface. The production of gaseous molecular oxygen is measured, revealing the potential of piezoelectric particles to generate oxygen under hypoxic conditions typical of some cancer environments. Finally, the best candidates, i.e. ZnO nano and micro particles, were tested on osteosarcoma and glioblastoma cell lines to demonstrate their potential for cancer treatment.

Nanoparticles-Delivered Circular RNA Strategy as a Novel Antitumor Approach

Anticancer therapy urgently needs the development of novel strategies. An innovative molecular target is represented by circular RNAs (circRNAs), single-strand RNA molecules with the 5' and 3' ends joined, characterized by a high stability. Although circRNA properties and biological functions have only been partially elucidated, their relationship and involvement in the onset and progression of cancer have emerged. Specific targeting of circRNAs may be obtained with antisense oligonucleotides and silencing RNAs. Nanotechnology is at the forefront of research for perfecting their delivery. Continuous efforts have been made to develop novel nanoparticles (NPs) and improve their performance, materials, and properties regarding biocompatibility and targeting capabilities. Applications in various fields, from imaging to gene therapy, have been explored. This review sums up the smart strategies developed to directly target circRNAs with the fruitful application of NPs in this context.

Anti-CD38 targeted nanotrojan horses stimulated by acoustic waves as therapeutic nanotools selectively against Burkitt's lymphoma cells

The horizon of nanomedicine research is moving toward the design of therapeutic tools able to be completely safe per se, and simultaneously be capable of becoming toxic when externally activated by stimuli of different nature. Among all the stimuli, ultrasounds come to the fore as an innovative approach to produce cytotoxicity on demand in presence of NPs, without invasiveness, with high biosafety and low cost. In this context, zinc oxide nanoparticles (NPs) are among the most promising metal oxide materials for theranostic application due to their optical and semi-conductor properties, high surface reactivity, and their response to ultrasound irradiation. Here, ZnO nanocrystals constitute the stimuli-responsive core with a customized biomimicking lipidic shielding, resembling the composition of natural extracellular vesicles. This core-shell hybrid structure provides high bio- and hemocompatibility towards healthy cells and is here proofed for the treatment of Burkitt's Lymphoma. This is a very common haematological tumor, typically found in children, for which consolidated therapies are so far the combination of chemo-therapy drugs and targeted immunotherapy. In this work, the proposed safe-by-design antiCD38-targeted hybrid nanosystem exhibits an efficient selectivity toward cancerous cells, and an on-demand activation, leading to a significant killing efficacy due to the synergistic interaction between US and targeted hybrid NPs. Interestingly, this innovative treatment does not significantly affect healthy B lymphocytes nor a negative control cancer cell line, a CD38- acute myeloid leukemia, being thus highly specific and targeted. Different characterization and analyses confirmed indeed the effective formation of targeted hybrid ZnO NPs, their cellular internalization and the damages produced in Burkitt's Lymphoma cells only with respect to the other cell lines. The presented work holds promises for future clinical applications, as well as translation to other tumor types.

Effective combination of biocompatible zinc oxide nanocrystals and high-energy shock waves for the treatment of colorectal cancer

Background

Colorectal cancer (CRC) is the third most diagnosed tumor worldwide, with a very high mortality rate, second only to lung cancer. Current treatments, such as surgery, chemotherapy or radiotherapy, are not effective enough and show several limitations. Among the emerging strategies, nanomedicine offers very powerful tools in cancer treatment. Recently, the combination of nanoparticle antitumor effect with a triggering external stimulation was formulated to boost up the cytotoxic activity.

Results

In this work, we show the synergistic effect of oleic acid-capped zinc oxide nanocrystals (ZnO NCs) and mechanical high-energy shock waves (SW) in the treatment for CRC cells, in vitro. We tested two different types of ZnO NCs synthetized in our laboratory, the basal undoped ZnO NCs and the iron-doped ones (Fe:ZnO NCs). The presence of the oleic acid capping and the further amino-propyl functionalization guarantee a high colloidal stability to both NCs, while the iron doping confers to Fe:ZnO NCs interesting magnetic properties useful for imaging applications in a clinical perspective. Thus, the iron-doped ZnO NCs are very attractive as potentially theranostic nanoparticles, allowing both stimuli-responsive therapy and magnetic resonance imaging.

Importantly, two colon adenocarcinoma cell lines, the HT-29 and the Dukes’ type C Colo 320DM cells were tested, both showing a good bio-tolerance and internalization rates of NCs. With the aim of eradicating the CRC cells, the possible synergism between the undoped/iron-doped ZnO NCs and an external physical stimulus, i.e., high-energy SW, was then here investigated in vitro. We demonstrated that the combined treatment resulted in an augmentation of the antitumor activity, especially for Colo 320DM cells, when compared to controls. Moreover, a repeated and sequenced SW treatment (three times/day, 3SW) after ZnO NCs exposure resulted in a further increased mortality of CRC cells.

Conclusion

Our work proposes the combination of the cytotoxic activity of ZnO NCs with the SW external stimulation to obtain a booster of the antitumor activity, which warrants further investigation in vivo on CRC as well as on other tumors.

Graphical Abstract

Development of doped ZnO-based biomimicking and tumor-targeted nanotheranostics to improve pancreatic cancer treatment

Despite different nanomaterials were developed so far against cancer, their potential drawbacks are still scarcely considered. The off-target delivery of a therapeutic compound, as well as the non-specific uptake of these nanomaterials by healthy tissues or organs, and their potential immunogenicity are some of the major issues that still have to be faced prior to a successful clinical translation. This work aims to develop an innovative theranostic, biocompatible, and drug-loaded nanoconstruct based on Gadolinium-doped Zinc Oxide (ZnO-Gd) nanocrystals (NCs), focusing on one of the most lethal diseases, i.e., pancreatic cancer. The use of zinc oxide is motivated by the huge potential of this nanomaterial already demonstrated for in vitro and in vivo applications, while the Gadolinium doping confers magnetic properties useful for diagnostics. Furthermore, an innovative biomimetic shell is here used to coat the NCs: it is composed of a lipid bilayer made from extracellular vesicles (EVs) combined with other synthetic lipids and a peptide targeting the pancreatic tumor microenvironment. To complete the nanoconstruct therapeutic function, Gemcitabine, a first-line drug for pancreatic cancer treatment, was adsorbed on the ZnO-Gd NCs prior to the coating with the above-mentioned lipidic shell. The aim of this work is thus to strongly enhance the therapeutic capability of the final nanoconstruct, providing it with high biocompatibility, colloidal stability in biological media, efficient cargo loading and release properties, as well as active targeting for site-selective drug delivery. Furthermore, the magnetic properties of the ZnO-Gd NCs core can in future allow efficient in situ bioimaging capabilities based on Magnetic Resonance Imaging technique. The obtained nanoconstructs were tested on two different pancreatic cancer cell lines, i.e., BxPC-3 and the metastatic AsPC-1, proving high cell internalization levels, mediated by the targeting peptide exposed on the nanoconstruct. Cellular cytotoxicity assay performed on both cell lines dictated ~ 20% increased cell killing efficacy of Gemcitabine when delivered through the nanoconstruct rather than as a free drug. Taken together, our designed theranostic nanoconstruct can have a significant impact on the standard treatment of pancreatic cancer.

Synergistic Phenomena between Iron-Doped ZnO Nanoparticles and Shock Waves Exploited against Pancreatic Cancer Cells

We propose the use of iron-doped zinc oxide nanoparticles (Fe:ZnO NPs) showing theranostic capabilities and being synergistically active against pancreatic ductal adenocarcinoma once combined with mechanical pressure waves, such as shock waves. Fe:ZnO NPs are synthesized by employing oleic acid as a capping agent and are functionalized with amino-propyl groups. We first report their superior characteristics with respect to undoped ZnO NPs in terms of magnetic properties, colloidal stability, cytocompatibility, and internalization into BxPC-3 pancreatic cancer cells in vitro. These Fe:ZnO NPs are also cytocompatible toward normal pancreatic cells. We then perform a synergistic cell treatment with both shock waves and Fe:ZnO NPs once internalized into cells. We also evaluate the contribution to the synergistic activity of the NPs located in the extracellular space. Results show that both NPs and shock waves, when administered separately, are safe to cells, while their combination provokes an enhanced cell death after 24 h. Various mechanisms are then considered, such as dissolution of NPs, production of free radicals, and cell membrane disruption or permeation. It is understood so far that iron-doped ZnO NPs can degrade intracellularly into zinc cations, while the use of shock waves produce cell membrane permeabilization and possible rupture. In contrast, the production of reactive oxygen species is here ruled out. The provoked cell death can be recognized in both apoptotic and necrotic events. The proposed work is thus a first proof-of-concept study enabling promising future applications to deep-seated tumors such as pancreatic cancer, which is still an unmet clinical need with a tremendous death rate.

A comparative analysis of low intensity ultrasound effects on living cells: from simulation to experiments

Ultrasounds are already broadly exploited in clinical diagnostics and are now becoming a powerful and not harmful tool in antitumoral therapies, as they are able to produce damages towards cancer cells, thank to inertial cavitation and temperature increase. The use of US alone or combined to molecular compounds, microbubbles or solid-state nanoparticles is the focus of current research and clinical trials, like thermoablation, drug sonoporation or sonodynamic therapies. In the present work, we discuss on the non-thermal effects of ultrasound and the conditions which enable oxygen radical production and which role they can have in provoking the death of different cancer cell lines. In this perspective, we set a mathematical model to predict the pressure spatial distribution in a defined water sample volume and thus obtain a map of acoustic pressures and acoustic intensities of the applied ultrasound at different input powers. We then validate and verify these numerical results with direct acoustic measurements and by detecting the production of reactive oxygen species (ROS) by means of sonochemiluminescence (SCL) and electron paramagnetic resonance (EPR) spectroscopy, applied to the same water sample volume and using the same US input parameters adopted in the simulation. Finally, the various US conditions are applied to two different set of cancer cell lines, a cervical adenocarcinoma and a hematological cancer, Burkitt’s lymphoma. We hypothesize how the ROS generation can influence the recorded cell death. In a second set of experiments, the role of semiconductor metal oxide nanocrystals, i.e. zinc oxide, is also evaluated by adding them to the water and biological systems. In particular, the role of ZnO in enhancing the ROS production is verified. Furthermore, the interplay among US and ZnO nanocrystals is evaluated in provoking cancer cell death at specific conditions. This study demonstrates a useful correlation between numerical simulation and experimental acoustic validation as well as with ROS measurement at both qualitative and quantitative levels during US irradiation of simple water solution. It further tries to translate the obtained results to justify one of the possible mechanisms responsible of cancer cell death. It thus aims to pave the way for the use of US in cancer therapy and a better understanding on the non-thermal effect that a specific set of US parameters can have on cancer cells cultured in vitro.

Ciprofloxacin-Loaded Titanium Nanotubes Coated with Chitosan: A Promising Formulation with Sustained Release and Enhanced Antibacterial Properties

Due to their high entrapment efficiency, anodized titanium nanotubes (TiO2-NTs) are considered effective reservoirs for loading/releasing strong antibiotics whose systemic administration is associated with diverse and severe side-effects. In this study, TiO2-NTs were synthesized by anodic oxidation of titanium foils, and the effects of electrolyte percentage and viscosity on their dimensions were evaluated. It was found that as the water content increased from 15 to 30%, the wall thickness, length, and inner diameter of the NTs increase from 5.9 to 15.8 nm, 1.56 to 3.21 µm, and 59 to 84 nm, respectively. Ciprofloxacin, a highly potent antibiotic, was loaded into TiO2-NTs with a high encapsulation efficiency of 93%, followed by coating with different chitosan layers to achieve a sustained release profile. The prepared formulations were characterized by various techniques, such as scanning electron microscopy, differential scanning calorimetry, and contact measurement. In vitro release studies showed that the higher the chitosan layer count, the more sustained the release. Evaluation of antimicrobial activity of the formulation against two endodontic species from Peptostreptococcus and Fusobacterium revealed minimum inhibitory concentrations (MICs) of 1 µg/mL for the former and the latter. To summarize, this study demonstrated that TiO2-NTs are promising reservoirs for drug loading, and that the chitosan coating provides not only a sustained release profile, but also a synergistic antibacterial effect.

Ultrasound and nanomaterial: an efficient pair to fight cancer

Ultrasounds are often used in cancer treatment protocols, e.g. to collect tumor tissues in the right location using ultrasound-guided biopsy, to image the region of the tumor using more affordable and easier to use apparatus than MRI and CT, or to ablate tumor tissues using HIFU. The efficacy of these methods can be further improved by combining them with various nano-systems, thus enabling: (i) a better resolution of ultrasound imaging, allowing for example the visualization of angiogenic blood vessels, (ii) the specific tumor targeting of anti-tumor chemotherapeutic drugs or gases attached to or encapsulated in nano-systems and released in a controlled manner in the tumor under ultrasound application, (iii) tumor treatment at tumor site using more moderate heating temperatures than with HIFU. Furthermore, some nano-systems display adjustable sizes, i.e. nanobubbles can grow into micro-bubbles. Such dual size is advantageous since it enables gathering within the same unit the targeting properties of nano bubbles via EPR effect and the enhanced ultrasound contrasting properties of micro bubbles. Interestingly, the way in which nano-systems act against a tumor could in principle also be adjusted by accurately selecting the nano-system among a large choice and by tuning the values of the ultrasound parameters, which can lead, due to their mechanical nature, to specific effects such as cavitation that are usually not observed with purely electromagnetic waves and can potentially help destroying the tumor. This review highlights the clinical potential of these combined treatments that can improve the benefit/risk ratio of current cancer treatments.

Engineered titania nanomaterials in advanced clinical applications

Significant advancement in the field of nanotechnology has raised the possibility of applying potent engineered biocompatible nanomaterials within biological systems for theranostic purposes. Titanium dioxide (titanium(IV) oxide/titania/TiO2) has garnered considerable attention as one of the most extensively studied metal oxides in clinical applications. Owing to the unique properties of titania, such as photocatalytic activity, excellent biocompatibility, corrosion resistance, and low toxicity, titania nanomaterials have revolutionized therapeutic approaches. Additionally, titania provides an exceptional choice for developing innovative medical devices and the integration of functional moieties that can modulate the biological responses. Thus, the current review aims to present a comprehensive and up-to-date overview of TiO2-based nanotherapeutics and the corresponding future challenges.

[Shock wave therapy in oncology: in vitro, in vivo, rehabilitation]

Extracorporeal shock wave therapy (ESWT) is a relatively new branch of physiotherapy.

PURPOSE OF THE STUDY

Conduct an analytical review of the available literature data on the use of ESWT in oncology.

MATERIAL AND METHODS

A review was conducted, including data from electronic databases: Scopus, Web of Science, MedLine, World Health Organization, The Cochrane Central Register of Controlled Trials, ScienceDirect, US National Library of Medicine National Institutes of Health, PubMed, Google Scholar, elibrary, CyberLeninka, disserCat.

RESULTS AND CONCLUSION

The study of ESWT in oncology is carried out in two directions: 1) impact on the tumor with the aim of its disintegration, inhibition of growth, enhancement of the action of radiation and/or chemotherapy; 2) rehabilitation of cancer patients. Shock waves in vitro and in vivo significantly reduce the viability and activate apoptosis of cell lines of osteosarcoma, cancer of the stomach, colon, rectum, bladder, breast, urothelial cancer of the upper urinary tract, adenocarcinoma of the cervix, Burkitt's lymphoma, sarcoma, anaplastic thyroid cancer glands, glioblastoma multiforme. Shock waves also sensitize tumor cells for adjuvant chemotherapy and increase its antitumor activity. The lack of a stimulating effect on a number of malignant tumors in this physical factor makes it possible to conduct ESWT studies in the rehabilitation of cancer patients. The data obtained by a number of authors indicate the clinical efficacy of ESWT in the rehabilitation of patients with erectile dysfunction after radical prostatectomy, with postmastectomy lymphedema of the upper limb, with myofascial pain syndrome after cervical lymph node dissection due to malignant neoplasms of the head and neck, with peripheral polyneuropathy induced by cytostatics. However, in order to develop indications and contraindications for the appointment of ESWT in the rehabilitation of cancer patients, it is not enough just to evaluate its clinical effectiveness; currently absent scientific studies with long-term follow-up of patients who received this method of physiotherapy are needed.