Synergistically Augmenting Cancer Immunotherapy by Physical Manipulation of Pyroptosis Induction.

Pyroptosis is a newly recognized type of programmed cell death mediated by the gasdermin family and caspase. It is characterized by the formation of inflammasomes and the following inflammatory responses. Recent studies have elucidated the value of pyroptosis induction in cancer treatment. The inflammatory cytokines produced during pyroptosis can trigger immune responses to suppress malignancy. Physical approaches for cancer treatment, including radiotherapy, light-based techniques (photodynamic and photothermal therapy), ultrasound-based techniques (sonodynamic therapy and focused ultrasound), and electricity-based techniques (irreversible electroporation and radiofrequency ablation), are effective in clinical application. Recent studies have reported that pyroptosis is involved in the treatment process of physical approaches. Manipulating pyroptosis using physical approaches can be utilized in combating cancer, according to recent studies. Pyroptosis-triggered immunotherapy can be combined with the original anti-tumor methods to achieve a synergistic therapy and improve the therapeutic effect. Studies have also revealed that enhancing pyroptosis may increase the sensitivity of cancer cells to some physical approaches. Herein, we present a comprehensive review of the literature focusing on the associations between pyroptosis and various physical approaches for cancer and its underlying mechanisms. We also discussed the role of pyroptosis-triggered immunotherapy in the treatment process of physical manipulation.

Suppressing Pancreatic Cancer Survival and Immune Escape via Nanoparticle-Modulated STING/STAT3 Axis Regulation.

Pancreatic ductal adenocarcinoma (PDAC) poses a challenge in oncology due to its high lethality and resistance to immunotherapy. Recently, emerging research on the stimulator of interferon gene (STING) pathway offers novel opportunities for immunotherapy. Although STING expression is retained in PDAC cells, the response of PDAC cells to STING agonists remains ineffective. Signal transducer and activator of transcription 3 (STAT3), a downstream pathway of STING, is notably overexpressed in pancreatic cancer and related to tumor survival and immune escape. We observed that inhibiting STAT3 signaling post-STING activation effectively suppressed tumor growth through signal transducer and activator of transcription 1 (STAT1)-mediated apoptosis but led to a potential risk of immune-related adverse events (irAEs). To address this issue, we designed a tumor-penetrating liposome for the codelivery of STING agonist and STAT3 inhibitor. These nanoparticles regulated the STING/STAT3 signaling axis and effectively inhibited the proliferation and survival of tumor. Simultaneously, we found a significant increase in the activation of NK cells and CD8+ T cells after treatment, leading to robust innate immunity and adaptive immune response. We highlight the potential of regulating the STING/STAT3 axis as a promising treatment for improving clinical outcomes in PDAC patients.

Effect of Surfactants on Eliminating Stable Ultrafine Chalcopyrite Froth.

Chalcopyrite is a primary source of copper in nature. However, with the increasing need to process low-grade and complex chalcopyrite ores, overly stable froth is becoming more and more common and poses operational and safety challenges. No reliable strategy has been developed to address the issue. As a new initiative, this study investigated three different structured surfactants, sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and pentadecafluorooctanoic acid (PFOA), which vary in hydrophobic group, aiming to modify the surfaces of ultrafine chalcopyrite particles and adjust the interfacial tension at the gas-liquid interface to eliminate stable ultrafine chalcopyrite froth. The fundamental hypothesis was that an ideal surfactant structure could adjust the particle surface wettability and interfacial tension to eliminate overly stable froth. Based on contact angle measurements and interfacial tension measurements using a Theta Flow tensiometer by the pendant drop method and the sessile drop method, it was demonstrated that the contact angle played a dominant role in defoaming, while the reduction of gas-liquid interfacial tension had an adverse effect. Additionally, defoaming tests indicated that SDBS had lower defoaming effectiveness than SDS at low surfactant concentrations due to the steric hindrance in its structure, whereas the addition of SDBS could achieve a froth reduction efficiency as high as 93.75% at higher surfactant concentrations due to its stronger hydrophobicity and adsorption capacity to chalcopyrite particles, which could reduce the contact angle from 70 to 37.62°. However, PFOA exhibited lower defoaming effectiveness than both SDS and SDBS due to its lipophobic fluorocarbon tail of PFOA and weaker adsorption capacity to chalcopyrite particles, making it unsuitable for eliminating stable ultrafine chalcopyrite froth.

Erratum: Porphyrin-grafted Lipid Microbubbles for the Enhanced Efficacy of Photodynamic Therapy in Prostate Cancer through Ultrasound-controlled In Situ Accumulation: Erratum.

[This corrects the article DOI: 10.7150/thno.22469.].

Photodynamically Tumor Vessel Destruction Amplified Tumor Targeting of Nanoparticles for Efficient Chemotherapy.

Efficient tumor-targeted drug delivery is still a challenging and currently unbreakable bottleneck in chemotherapy for tumors. Nanomedicines based on passive or active targeting strategy have not yet achieved convincing chemotherapeutic benefits in the clinic due to the tumor heterogeneity. Inspired by the efficient inflammatory-cell recruitment to acute clots, we constructed a two-component nanosystem, which is composed of an RGD-modified pyropheophorbide-a (Ppa) micelle (PPRM) that mediates the tumor vascular-targeted photodynamic reaction to activate local coagulation and subsequently transmits the coagulation signals to the circulating clot-targeted CREKA peptide-modified camptothecin (CPT)-loaded nanodiscs (CCNDs) for amplifying tumor targeting. PPRM could effectively bind with the tumor vasculature and induce sufficient local thrombus by a photodynamic reaction. Local photodynamic reaction-induced tumor target amplification greatly increased the tumor accumulation of CCND by 4.2 times, thus significantly enhancing the chemotherapeutic efficacy in the 4T1 breast tumor model. In other words, this study provides a powerful platform to amplify tumor-specific drug delivery by taking advantage of the efficient crosstalk between the PPRM-activated coagulation cascade and clot-targeted CCND.

Heritable CRISPR Mutagenesis of Essential Maternal Effect Genes as a Simple Tool for Sustained Population Suppression of Invasive Species in a Zebrafish Model.

Invasive species control is important for ecological and agricultural management. Genetic methods can provide species specificity for population control. We developed heritable maternal effect embryo lethality (HMEL), a novel strategy allowing negative population pressure from HMEL individuals to be transmitted within a population across generations. We demonstrate the HMEL technique in zebrafish through genome-integrated CRISPR/Cas targeted mutagenic disruption of nucleoplasmin 2b (npm2b), a female-specific essential maternal effect gene, causing heritable sex-limited disruption of reproduction. HMEL-induced high-efficiency mutation of npm2b in females suppresses population, while males transmit the HMEL allele across generations. HMEL could be easily modified to target other genes causing sex-specific sterility, or generalized to control invasive fish or other vertebrate species for environmental conservation or agricultural protection.

Manipulating Redox Homeostasis of Cancer Stem Cells Overcome Chemotherapeutic Resistance through Photoactivatable Biomimetic Nanodiscs.

Tumor heterogeneity remains a significant obstacle in cancer therapy due to diverse cells with varying treatment responses. Cancer stem-like cells (CSCs) contribute significantly to intratumor heterogeneity, characterized by high tumorigenicity and chemoresistance. CSCs reside in the depth of the tumor, possessing low reactive oxygen species (ROS) levels and robust antioxidant defense systems to maintain self-renewal and stemness. A nanotherapeutic strategy is developed using tumor-penetrating peptide iRGD-modified high-density lipoprotein (HDL)-mimetic nanodiscs (IPCND) that ingeniously loaded with pyropheophorbide-a (Ppa), bis (2-hydroxyethyl) disulfide (S-S), and camptothecin (CPT) by synthesizing two amphiphilic drug-conjugated sphingomyelin derivatives. Photoactivatable Ppa can generate massive ROS which as intracellular signaling molecules effectively shut down self-renewal and trigger differentiation of the CSCs, while S-S is utilized to deplete GSH and sustainably imbalance redox homeostasis by reducing ROS clearance. Simultaneously, the depletion of GSH is accompanied by the release of CPT, which leads to subsequent cell death. This dual strategy successfully disturbed the redox equilibrium of CSCs, prompting their differentiation and boosting the ability of CPT to kill CSCs upon laser irradiation. Additionally, it demonstrated a synergistic anti-cancer effect by concurrently eliminating therapeutically resistant CSCs and bulk tumor cells, effectively suppressing tumor growth in CSC-enriched heterogeneous colon tumor mouse models.

Pyroptosis Induction with Nanosonosensitizer-Augmented Sonodynamic Therapy Combined with PD-L1 Blockade Boosts Efficacy against Liver Cancer.

Induction of pyroptosis can promote anti-PD-L1 therapeutic efficacy due to the release of pro-inflammatory cytokines, but current approaches can cause off target toxicity. Herein, a phthalocyanine-conjugated mesoporous silicate nanoparticle (PMSN) is designed for amplifying sonodynamic therapy (SDT) to augment oxidative stress and induce robust pyroptosis in tumors. The sub-10 nm diameter structure and c(RGDyC)-PEGylated modification enhance tumor targeting and renal clearance. The unique porous architecture of PMSN doubles ROS yield and enhances pyroptotic cell populations in tumors (25.0%) via a cavitation effect. PMSN-mediated SDT treatment efficiently reduces tumor mass and suppressed residual tumors in treated and distant sites by synergizing with PD-L1 blockade (85.93% and 77.09%, respectively). Furthermore, loading the chemotherapeutic, doxorubicin, into PMSN intensifies SDT-pyroptotic effects and increased efficacy. This is the first report of the use of SDT regimens to induce pyroptosis in liver cancer. This noninvasive and effective strategy has potential for clinical translation.

Ultrasound contrast agents from microbubbles to biogenic gas vesicles.

Microbubbles have been the earliest and most widely used ultrasound contrast agents by virtue of their unique features: such as non-toxicity, intravenous injectability, ability to cross the pulmonary capillary bed, and significant enhancement of echo signals for the duration of the examination, resulting in essential preclinical and clinical applications. The use of microbubbles functionalized with targeting ligands to bind to specific targets in the bloodstream has further enabled ultrasound molecular imaging. Nevertheless, it is very challenging to utilize targeted microbubbles for molecular imaging of extravascular targets due to their size. A series of acoustic nanomaterials have been developed for breaking free from this constraint. Especially, biogenic gas vesicles, gas-filled protein nanostructures from microorganisms, were engineered as the first biomolecular ultrasound contrast agents, opening the door for more direct visualization of cellular and molecular function by ultrasound imaging. The ordered protein shell structure and unique gas filling mechanism of biogenic gas vesicles endow them with excellent stability and attractive acoustic responses. What's more, their genetic encodability enables them to act as acoustic reporter genes. This article reviews the upgrading progresses of ultrasound contrast agents from microbubbles to biogenic gas vesicles, and the opportunities and challenges for the commercial and clinical translation of the nascent field of biomolecular ultrasound.

Manipulating Neovasculature-Targeting Capability of Biomimetic Nanodiscs for Synergistic Photoactivatable Tumor Infarction and Chemotherapy.

Tumor infarction therapy is a promising antitumor strategy with the advantages of taking a short therapy duration, less risk of resistance, and effectiveness against a wide range of tumor types. However, its clinical application is largely hindered by tumor recurrence in the surviving rim and the potential risk of thromboembolic events due to nonspecific vasculature targeting. Herein, a neovasculature-targeting synthetic high-density lipoprotein (sHDL) nanodisc loaded with pyropheophorbide-a and camptothecin (CPN) was fabricated for photoactivatable tumor infarction and synergistic chemotherapy. By manipulating the anisotropy in ligand modification of sHDL nanodiscs, CPN modified with neovaculature-targeting peptide on the planes (PCPN) shows up to 7-fold higher cellular uptake compared with that around the edge (ECPN). PCPN can efficiently bind to endothelial cells of tumor vessels, and upon laser irradiation, massive local thrombus can be induced by the photodynamic reaction to deprive nutrition supply. Meanwhile, CPT could be released in response to the tumor reductive environment, thus killing residual tumor cells in the surviving rim to inhibit recurrence. These findings not only offer a powerful approach of synergistic cancer therapy but also suggest the potential of plane-modified sHDL nanodiscs as a versatile drug delivery nanocarrier.

Major Strategies for Spatial Control of Ultrasound-Driven Gene Expression to Enhance Therapeutic Specificity.

A major challenge of gene therapy is to achieve highly specific transgene expression in tissues of interest with minimized off-target expression. Ultrasound in combination with microbubbles can transiently increase permeability of desired cells or tissues and thereby facilitate gene transfer. This kind of ultrasound-driven transgene expression has gained increasing attention due to its deep tissue penetration and high spatiotemporal resolution. However, successful genetic manipulation in vivo with ultrasound need to well optimize various aspects involved in this process. Ultrasound parameters, microbubble dose, and gene vectors need to be optimized for highly increased transgene expression in the cells of interest. Conversely, the potential off-target transgene expression and toxicities need to be reduced by modification of gene vectors and/or promoter sequence. This review will discuss some major strategies for enhanced specificity of the ultrasound-mediated gene transfer in vivo. Five major strategies will be discussed, including the integration of real-time imaging methods, local injection, targeted microbubbles loaded with nucleic acids, stealth nanocarriers, and cell-specific promoter. The advantages and limitations of each strategy were outlined, hoping to provide a guideline for researchers in achieving high specific ultrasound-driven gene expression.

Biogenic Imaging Contrast Agents.

Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly important role in biomedical research ranging from subcellular level to individual level. The unique properties of BICAs, including expression by cells as reporters and specific genetic modification, facilitate various in vitro and in vivo studies, such as quantification of gene expression, observation of protein interactions, visualization of cellular proliferation, monitoring of metabolism, and detection of dysfunctions. Furthermore, in human body, BICAs are remarkably helpful for disease diagnosis when the dysregulation of these agents occurs and can be detected through imaging techniques. There are various BICAs matched with a set of imaging techniques, including fluorescent proteins for fluorescence imaging, gas vesicles for ultrasound imaging, and ferritin for magnetic resonance imaging. In addition, bimodal and multimodal imaging can be realized through combining the functions of different BICAs, which helps overcome the limitations of monomodal imaging. In this review, the focus is on the properties, mechanisms, applications, and future directions of BICAs.

Enhancing Photodynamic Therapy Efficacy Against Cancer Metastasis by Ultrasound-Mediated Oxygen Microbubble Destruction to Boost Tumor-Targeted Delivery of Oxygen and Renal-Clearable Photosensitizer Micelles.

Hypoxic tumor microenvironment and nonspecific accumulation of photosensitizers are two key factors that limit the efficacy of photodynamic therapy (PDT). Herein, a strategy of oxygen microbubbles (MBs) boosting photosensitizer micelles is developed to enhance PDT efficacy and inhibit tumor metastasis by self-assembling renal-clearable ultrasmall poly(ethylene glycol)-modified protoporphyrin IX micelles (PPM) and perfluoropentane (PFP)-doped oxygen microbubbles (OPMBs), followed by ultrasound imaging-guided OPMB destruction to realize the tumor-targeted delivery of PPM and oxygen in tumor. Doping PFP into oxygen MBs increases the production of MBs and stability of oxygen MBs, allowing for persistent circulation in blood. Following co-injection, destruction of OPMBs with ultrasound leads to ∼2.2-fold increase of tumor-specific PPM accumulation. Furthermore, the burst release of oxygen by MB destruction improves tumor oxygenation from 22 to 50%, which not only raises the production of singlet oxygen but also significantly reduces the expression of hypoxia-inducible factor-1 alpha and related genes, thus preventing angiogenesis and epithelial-mesenchymal transition. It is verified that this strategy effectively eradicates orthotopic breast cancer and inhibits lung metastasis. Furthermore, the survival rate of mice bearing orthotopic pancreatic tumor is significantly extended by such interventional PDT strategy. Therefore, the combination of ultrasmall PPM and OPMBs represents a simple but effective strategy in overcoming the limitations of PDT.

Asymmetric, amphiphilic RGD conjugated phthalocyanine for targeted photodynamic therapy of triple negative breast cancer.

Targeted photodynamic therapy (TPDT) is considered superior to conventional photodynamic therapy due to the enhanced uptake of photosensitizers by tumor cells. In this paper, an amphiphilic and asymmetric cyclo-Arg-Gly-Asp-d-Tyr-Lys(cRGDyK)-conjugated silicon phthalocyanine (RSP) was synthesized by covalently attaching the tripeptide Arg-Gly-Asp (RGD) to silicone phthalocyanine in the axial direction for TPDT of triple-negative breast cancer (TNBC). RSP was characterized by spectroscopy as a monomer in physiological buffer. Meanwhile, the modification of RSP with RGD led to a high accumulation of the photosensitizer in TNBC cells overexpressing ανß3 integrin receptors which can bind RGD, greatly reducing the risk of phototoxicity. In vitro photodynamic experiments showed that the IC50 of RSP was 295.96 nM in the 4T1 cell line, which caused significant apoptosis of the tumor cells. The tumor inhibition rate of RSP on the orthotopic murine TNBC achieved 74%, while the untargeted photosensitizer exhibited no obvious tumor inhibition. Overall, such novel targeted silicon phthalocyanine has good potential for clinical translation due to its simple synthesis route, strong targeting, and high therapeutic efficacy for TPDT treatment of TNBC.

Stable flow-induced expression of KLK10 inhibits endothelial inflammation and atherosclerosis.

Atherosclerosis preferentially occurs in arterial regions exposed to disturbed blood flow (d-flow), while regions exposed to stable flow (s-flow) are protected. The proatherogenic and atheroprotective effects of d-flow and s-flow are mediated in part by the global changes in endothelial cell (EC) gene expression, which regulates endothelial dysfunction, inflammation, and atherosclerosis. Previously, we identified kallikrein-related peptidase 10 (Klk10, a secreted serine protease) as a flow-sensitive gene in mouse arterial ECs, but its role in endothelial biology and atherosclerosis was unknown. Here, we show that KLK10 is upregulated under s-flow conditions and downregulated under d-flow conditions using in vivo mouse models and in vitro studies with cultured ECs. Single-cell RNA sequencing (scRNAseq) and scATAC sequencing (scATACseq) study using the partial carotid ligation mouse model showed flow-regulated Klk10 expression at the epigenomic and transcription levels. Functionally, KLK10 protected against d-flow-induced permeability dysfunction and inflammation in human artery ECs, as determined by NFκB activation, expression of vascular cell adhesion molecule 1 and intracellular adhesion molecule 1, and monocyte adhesion. Furthermore, treatment of mice in vivo with rKLK10 decreased arterial endothelial inflammation in d-flow regions. Additionally, rKLK10 injection or ultrasound-mediated transfection of Klk10-expressing plasmids inhibited atherosclerosis in Apoe-/- mice. Moreover, KLK10 expression was significantly reduced in human coronary arteries with advanced atherosclerotic plaques compared to those with less severe plaques. KLK10 is a flow-sensitive endothelial protein that serves as an anti-inflammatory, barrier-protective, and anti-atherogenic factor.

Ultrasmall porphyrin-silica core-shell dots for enhanced fluorescence imaging-guided cancer photodynamic therapy.

Clinically used small-molecular photosensitizers (PSs) for photodynamic therapy (PDT) share similar disadvantages, such as the lack of selectivity towards cancer cells, short blood circulation time, life-threatening phototoxicity, and low physiological solubility. To overcome such limitations, the present study capitalizes on the synthesis of ultra-small hydrophilic porphyrin-based silica nanoparticles (core-shell porphyrin-silica dots; PSDs) to enhance the treatment outcomes of cancer via PDT. These ultra-small PSDs, with a hydrodynamic diameter less than 7 nm, have an excellent aqueous solubility in water (porphyrin; TPPS3-NH2) and enhanced tumor accumulation therefore exhibiting enhanced fluorescence imaging-guided PDT in breast cancer cells. Besides ultra-small size, such PSDs also displayed an excellent biocompatibility and negligible dark cytotoxicity in vitro. Moreover, PSDs were also found to be stable in other physiological solutions as a function of time. The fluorescence imaging of porphyrin revealed a prolonged residence time of PSDs in tumor regions, reduced accumulation in vital organs, and rapid renal clearance upon intravenous injection. The in vivo study further revealed reduced tumor growth in 4T1 tumor-bearing bulb mice after laser irradiation explaining the excellent photodynamic therapeutic efficacy of ultra-small PSDs. Thus, ultrasmall hydrophilic PSDs combined with excellent imaging-guided therapeutic abilities and renal clearance behavior represent a promising platform for cancer imaging and therapy.