Acidic Microenvironment Research Articles

Abstract B002: Dynamic response and evolving adaptation of pancreatic cancer cells to the prolonged acidic pH microenvironment

Abstract Solid tumor cells are often immersed in an acidic microenvironment. While many previous studies have investigated the short-term effects of extracellular acidity on tumor cells, little is known about how they adapt to the prolonged acidic microenvironmental stress and then advance to more aggressive stages. By challenging pancreatic tumor cells as an example with continuously and gradually acidified extracellular pH, a variety of cellular characteristics including phenotypic regulation, proliferation rates, autophagic control, metabolic plasticity and metastatic potentials were identified. More detailed evidence regarding the mitochondrial network dynamics and mechanistic control of pancreatic tumor cells in response to the extracellular acidosis will be presented at this conference to emphasize the critical effects of this stress factor as a selection force for tumor adaptation and progression. These findings not only highlight the importance of dynamic response and evolving adaptation of solid tumor cells to the chronic microenvironmental acidity, but also the potential of targeting the 'acid-mediated tumor malignancy' for anticancer therapy. Citation Format: Wun-Shaing Wayne Chang. Dynamic response and evolving adaptation of pancreatic cancer cells to the prolonged acidic pH microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B002.

LysSYL-Loaded pH-Switchable Self-Assembling Peptide Hydrogels Promote Methicillin-Resistant Staphylococcus Aureus Elimination and Wound Healing.

Staphylococcus aureus (S. aureus), especially methicillin-resistant S. aureus (MRSA), causes wound infections, whose treatment remains a clinical challenge. Bacterium-infected wounds often create acidic niches with a pH 4.5-6.5. Endolysin LysSYL, which is derived from phage SYL, shows promise as an antistaphylococcal agent. However, endolysins generally exhibit instability and possess low bioavailability in acidic microenvironments. Here, an array of self-assembling peptides is designed, and peptide L5 is screened out based on its gel formation property and bioavailability. L5 exerted a pH-switchable antimicrobial effect (pH 5.5) and formed biocompatible hydrogels at neutral pH (pH 7.4). The LysSYL-loaded L5 can assemble L5@LysSYL hydrogels, increase thermal stability, and exhibit the slow-release effect of LysSYL. Effective elimination of S. aureus is achieved by L5@LysSYL through bacterial membrane disruption and cell separation inhibition. Moreover, L5@LysSYL hydrogels exhibit great potential in promoting wound healing in a mouse wound model infected by MRSA. Furthermore, L5@LysSYL hydrogels are safe and can decrease the cytokine levels and increase the number of key factors for vessel formation, which contribute to wound healing. Overall, the self-assembling L5@LysSYL can effectively clean MRSA and promote wound healing, which suggests its potential as a pH-sensitive wound dressing for the management of wound infections.

ASIC1a regulates airway epithelial cell pyroptosis in acute lung injury by NLRP3-Caspase1-GSDMD pathway.

Acidosis is the most common complication that seriously affects the prognosis of acute respiratory distress syndrome (ARDS). Acid-sensitive ion channel 1a (ASIC1a) is activated in acidic environments to regulate inflammatory process. However, the role of ASIC1a in ARDS is unclear. In this study, we examined the expression of ASIC1a in airway epithelial cells in an acidic environment. We then investigated whether blocking ASIC1a could inhibit pyroptosis of airway epithelial cells and the molecular mechanism. In the mouse acute lung injury (ALI) model, we observed the changes of lung histopathology, arterial blood gas and pyroptosis related indexes after ASIC1a inhibition. Bronchoalveolar lavage fluid (BALF) from patients with ARDS were collected to explore the expression level of ASIC1a in ARDS patients. Inhibiting ASIC1a can reduce the airway epithelial cell pyroptosis induced by an extracellular acidic environment. ASIC1a can bind to PRKACA, and silencing ASIC1a and PRKACA can inhibit the occurrence of pyroptosis in airway epithelial cells. Compared with control group, arterial blood pH and PaO2 in ALI group were significantly reduced. The inflammation in the lungs is more intense, and the mRNA and protein of NLRP3, Caspase1 and GSDMD were increased, while ASIC1a specific blocker psalmotoxin-1 alleviated this phenomenon. The expression of ASIC1a in BALF of ARDS patients was significantly increased, especially in non-survival group. Acidic micro-environment can induce the increased expression of ASIC1a, and inhibition of ASIC1a can alleviate the inflammation and airway epithelial cell pyroptosis in ARDS. ASIC1a may be a new target for the treatment of ARDS.

Engineering Strain-Defects to Enhance Enzymatic Therapy and Induce Ferroptosis.

The effect of mimetic enzyme catalysis is often limited by insufficient activity and a single therapy is not sufficient to meet the application requirements. In this study, a multifunctional nanozyme, MMSR-pS-PEG, is designed and fabricated by modifying poly (ethylene glycol) grafted phosphorylated serine (pS-PEG) on mesoporous hollow MnMoOx spheres, followed by loading sorafenib (SRF) into the pores. Strain engineering-induced oxygen defects endow the nanozyme with enhanced dual-enzymatic activity to mimic catalase and oxidase-like activities, which catalyze the conversion of endogenous H2O2 into oxygen and subsequently into superoxide ions in the acidic tumor microenvironment. Moreover, as an n-type semiconductor, MnMoOx generates reactive oxygen species by separating electrons and holes upon ultrasonic irradiation and simultaneously deplete glutathione by holes, thereby further augmenting its catalytic effect. As a ferroptosis inducer, SRF restrains the system xc - and indirectly inhibits glutathione synthesis, synergistically interacting with the nanozyme to stimulate ferroptosis by promoting lipid peroxidation and accumulation and the downregulation of glutathione peroxidase 4. These results provide valuable insights into the design of enzymatic therapy with high performance and highlight a promising approach for the synergism of ferroptosis and enzymatic tumor therapy.

Donor Substitution Engineering of Hemicyanine Nanoparticles to Reprogram the Tumor Microenvironment and Enhance Fn14‐Targeted BiTE for Glioblastoma Photoimmunotherapy

AbstractGlioblastoma (GBM) is a highly malignant intracranial tumor with limited treatment options. Bispecific T‐cell engagers (BiTEs) are being explored for GBM treatment, but their success is hindered by inadequate T cell infiltration and activation due to the acidic and immunosuppressive microenvironment. Photothermal immunotherapy lyses tumors and activates immune responses, complementing BiTEs. This study innovatively employs a donor engineering strategy to develop hemicyanine dyes (Hcys) that emit from near‐infrared (NIR) I to NIR II. The Hcy with excellent properties is encapsulated in an amphiphilic micelle, forming a nano assembly with lactate oxidase (PLH1100). PLH1100 exhibits spectral absorption at 980 nm, a photothermal conversion efficiency of 58.7%, and capability for NIR‐II tumor imaging. Besides photothermal tumor ablation, PLH1100 regulates lactic acid metabolism and activates immunogenic cell death, improving the tumor microenvironment and promoting T cell infiltration and activation. Further studies demonstrate PLH1100 effectively kills human and murine GBM cells, inhibits orthotopic U87 tumor growth in BALB/c‐nu mice, and enhances the efficacy of Fn14‐targeted BiTE in orthotopic GL261 tumors in C57BL/6 mice, achieving a synergistic “1+1>2” therapeutic effect. Collectively, this work opens a new pathway for using Hcy‐based molecules combined with BiTE drugs for GBM therapy, with significant clinical potential.

Construction of acidic microenvironment by Cu-TCPP nanozyme composited deprotonatable polymeric nanofibers for efficient antibacterial activity

The issue of bacterial resistance caused by conventional antibiotics has emerged as a major challenge in clinical treatment. Nanozymes, based on catalysis and devoid of bacterial resistance, provide a novel approach to eradicating bacteria. However, the practical potential of these nanozymes is limited by their low and readily pH-affected catalytic activity. Herein, the enzyme activity was optimized starting from the synthesis of nanozyme and the selection of carboxylate-containing polymers for the matrix. Specifically, various copper-tetrakis (4-carboxyphenyl) porphyrin (Cu-TCPP) were initially synthesized employing three copper sources, and among them, Cu-TCPP derived from Cu2O with higher catalytic activity was preferred. Subsequently, Cu-TCPP composite fibrous membranes were further obtained by electrospinning from their blend solutions with different polymers with distinct deprotonation capabilities. Thus, an acidic microenvironment conducive to the exertion of enzyme activity was constructed. The fabricated composite nanofibrous membrane could dissociate hydrogen ions to construct a localized acidic microenvironment even under weakly alkaline conditions, thereby enhancing the enzyme activity and improving the antibacterial effect. Further in vivo experiments demonstrated its favorable antibacterial ability and accelerated wound healing effect. The enhancement strategy of enzyme activity in this study brings inspiration for the design of nanozyme composited wound dressings and holds significant potential for clinical antibacterial applications

Proton pump inhibitor attenutes acidic microenvironment to improve the therapeutic effects of MSLN-CAR-T cells on the brain metastasis of solid tumors

The incidence of brain metastasis (BM) is gradually increasing, and the prognosis and therapeutic effect are poor. The emergence of immunotherapy has brought hope for the development of BM treatments. This study revealed that compared with primary cancers (PCs), BMs have a “colder” and more acidic tumor microenvironment (TME), resulting in reduced protein levels of mesothelin (MSLN), a promising target for chimeric antigen receptor-T (CAR-T) cell therapy for triple-negative breast cancer (TNBC) with BMs. These factors could significantly decrease the efficiency of MSLN-CAR-T cells in TNBC BMs. Pantoprazole (PPZ) administration at the most commonly used dose in the clinic notably increased the pondus hydrogenii (pH) of the TME, inhibited lysosomal activity, increased the membrane levels of the MSLN protein and improved the killing ability of MSLN-CAR-T cells both in vitro and in vivo. Similar results were obtained in non-small cell lung cancer (NSCLC) BMs. Hence, when administered in combination with CAR-T cells, PPZ, which increases the protein levels of target antigens, may constitute a new immunotherapeutic strategy for treating solid tumors with BMs.

Precise photothermal treatment of bacterial infection mediated by charge-switchable nanoplatform with acylsulfonamide betaine surface

Photothermal therapy (PTT) offers a promising approach for the treatment of drug-resistant bacterial-infected wounds, yet it requires precise targeting of thermal damage to bacteria rather than healthy tissues. Herein, ultrasmall CuS NPs modified with polyzwitterion containing acylsulfonamide betaine (PCBSA@CuS), which provides a sensitive and reversible charge conversion around pH 6.8, are used to enhance the healing of bacteria-infected wounds. In the acidic infection microenvironment, the majority of PCBSA@CuS can electrostatically adsorb onto bacterial cells through cationic exposure, resulting in direct damage and death of bacteria upon NIR irradiation. Additionally, the photothermal NPs rapidly return to a zwitterionic nature in normal physiological environments, ensuring lower affinity and avoiding thermal damage to healthy tissues during continuous PTT. Compared to inert photothermal systems such as PEG-modified CuS NPs, the NPs used in this study exhibited higher bactericidal and wound healing efficacy. Therefore, this nano-antibacterial agent with highly sensitive thermal-targeting function provides a novel photothermal strategy for efficient and biosafe treatment of infected wounds.

Intratumoral lactic acid neutralization strategy for boosting chemoimmunotherapy using liposomal sodium bicarbonate

Glycolysis-related lactic acid overproduction creates an “ion-trapping” barrier and immunosuppressive tumor microenvironment that compromise effective intratumoral drug delivery and therapy. Therefore, normalization of tumor microenvironment via lactic acid neutralization can be a promising avenue for overcoming this therapeutic hurdle. In this study, the flexible liposomes loaded with sodium bicarbonate (NaHCO3@Flip) were used as a nano-adjuvant to boost chemoimmunotherapy. Their effects on assisting DOXIL and anti-PD-1 therapy were investigated. NaHCO3@Flip achieved deep tumor penetration, with the ability to neutralize lactic acid and normalize the acidic tumor microenvironment. NaHCO3@Flip is biosafe and can enhance cellular uptake efficiency of doxorubicin (DOX) by overcoming the ion-trapping barrier and amplify immunogenic cell death induced by DOX. The combination therapy of liposomal DOX and NaHCO3@Flip demonstrated enhanced inhibition of tumor growth. NaHCO3@Flip can also synergize with PD-1 antibody therapy. NaHCO3@Flip has the potential to serve as a therapeutic adjuvant for boosting chemoimmunotherapy by overcoming the ion-trapping effect and normalizing the tumor microenvironment.

Proton nanomodulators for enhanced Mn2+-mediated chemodynamic therapy of tumors via HCO3− regulation

BackgroundMn2+-mediated chemodynamic therapy (CDT) has been emerged as a promising cancer therapeutic modality that relies heavily on HCO3− level in the system. Although the physiological buffers (H2CO3/HCO3−) provide certain amounts of HCO3−, the acidity of the tumor microenvironment (TME) would seriously affect the HCO3− ionic equilibrium (H2CO3 ⇌ H+ + HCO3−). As a result, HCO3− level in the tumor region is actually insufficient to support effective Mn2+-mediated CDT.ResultsIn this study, a robust nanomodulator MnFe2O4@ZIF-8 (PrSMZ) with the capability of in situ self-regulation HCO3− is presented to enhance therapeutic efficacy of Mn2+-mediated CDT. Under an acidic tumor microenvironment, PrSMZ could act as a proton sponge to shift the HCO3− ionic equilibrium to the positive direction, significantly boosting the generation of the HCO3−. Most importantly, such HCO3− supply capacity of PrSMZ could be finely modulated by its ZIF-8 shell thickness, resulting in a 1000-fold increase in reactive oxygen species (ROS) generation. Enhanced ROS-dependent CDT efficacy is further amplified by a glutathione (GSH)-depletion ability and the photothermal effect inherited from the inner core MnFe2O4 of PrSMZ to exert the remarkable antitumor effect on mouse models.ConclusionsThis work addresses the challenge of insufficient HCO3− in the TME for Mn2+-mediated Fenton catalysts and could provide a promising strategy for designing high-performance Mn2+-mediated CDT agents to treat cancer effectively.

Gelation embolism agents suppress clinical TACE-incited pro-metastatic microenvironment against hepatocellular carcinoma progression

Current embolic agents in transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) encounter instability and easy leakage, discounting TACE efficacy with residual HCC. Moreover, clinical TACE aggravates hypoxia and pro-metastatic microenvironments, rendering patients with HCC poor prognosis. Herein, we developed Zein-based embolic agents that harness water-insoluble but ethanol-soluble Zein to encompass doxorubicin (DOX)-loaded mesoporous hollow MnO2 (HMnO2). The conditions and capacity of HMnO2 to generate reactive oxygen species (ROS) were assayed. Mechanical examinations of Zein-HMnO2@DOX were performed to evaluate its potential as the embolic agent. Invitro experiments were carried out to evaluate the effect of Zein-HMnO2@DOX on HCC. The subcutaneous HCC mouse model and rabbit VX2 HCC model were established to investigate its anti-tumor and anti-metastasis efficacy and explore its potential anti-tumor mechanism. The high adhesion and crosslinking of Zein with HMnO2@DOX impart Zein-HMnO2@DOX with strong mechanical strength to resist deformation and wash-off. Zein gelation and HMnO2 decomposition in response to water and acidic tumor microenvironment, respectively, enable continuous DOX release and Fenton-like reaction for reactive oxygen species (ROS) production and O2 release to execute ROS-enhanced TACE. Consequently, Zein-based embolic agents outperform clinically-used lipiodol to significantly inhibit orthotopic HCC growth. More significantly, O2 release down-regulates hypoxia inducible factor (HIF-1α), vascular endothelial growth factor (VEGF) and glucose transporter protein 1 (GLUT1), which thereby re-programmes TACE-aggravated hypoxic and pro-metastatic microenvironments to repress HCC metastasis towards lung. Mechanistic explorations uncover that such Zein-based TACE agents disrupt oxidative stress, angiogenesis and glycometabolism pathways to inhibit HCC progression. This innovative work not only provides a new TACE agent for HCC, but also establishes a new strategy to ameliorate TACE-aggravated hypoxia and metastasis motivation against clinically-common HCC metastasis after TACE operation. Excellent Young Science Fund for National Natural Science Foundation of China (82022033); National Natural Science Foundation of China (Grant No. 82373086, 82102761); Major scientific and technological innovation project of Wenzhou Science and Technology Bureau (Grant No. ZY2021009); Shanghai Young Top-Notch Talent.

Engraftment of a Surrogate Antigen onto Tumor Cell Surface via pHLIP Peptide to Universally Target CAR-T Cell Therapy to Solid Tumors

CAR-T cells and monoclonal antibodies (mAbs) are immunotherapeutics that have shown efficacies against certain malignancies. However, their broad application is hindered by the scarcity of tumor-associated antigens on tumor cell surfaces. Previous investigations unveiled the unique capacity of pH-low insertion peptide (pHLIP) to anchor to plasma membranes under acidic conditions. Considering that an acidic tumor microenvironment is a hallmark of solid tumors, we engineered a novel peptide, Myc-pHLIP, by tethering a surrogate epitope tag, the c-Myc-tag, to pHLIP. We evaluated the efficiency of Myc-pHLIP in inserting the artificial c-Myc-tag onto the plasma membrane of malignant cells and determined if this engraftment could convert it into a therapeutic target for CAR-T cells or mAbs. Our in vitro experiments demonstrated that incubating Myc-pHLIP with tumor cells in acidic media triggered significant killing by either Myc-targeted CAR-T cells (Myc-CAR-T), or by an anti-Myc mAb in the presence of NK cells. In vivo studies demonstrated substantial antitumor effects with sequential administration of Myc-pHLIP followed by either Myc-CAR-T or Myc-mAb. These findings establish that Myc-pHLIP has the potential to act as a universal surrogate tumor antigen capable of directing CAR-T cells or mAbs to treat any solid tumors by concurrently targeting both malignant and stromal cells.

Biomimetic nanoparticles co-deliver hirudin and lumbrukinase to ameliorate thrombus and inflammation for atherosclerosis therapy

Atherosclerosis (AS) is a progressive inflammatory disease, and thrombosis most probably leads to cardiovascular morbidity and mortality globally. Thrombolytic drugs alone cannot completely prevent thrombotic events, and treatments targeting thrombosis also need to regulate the inflammatory process. Based on the pathological process of AS dynamic development, biomimetic thrombus-targeted nanoparticles HMTL@PM were prepared. Hirudin and lumbrukinase, the effective substances of traditional Chinese medicine, were self-assembled under the action of tannic acid and Mn2+. HMTL@PM dissociated in the weakly acidic microenvironment of atherosclerosis and exhibited an excellent therapeutic effect of alleviating inflammation, dissolving thrombus, anticoagulation, and promoting cholesterol efflux. HMTL@PM effectively regulated the progression of AS and provided a new perspective for the development of drug delivery systems for AS therapy, which owned important research significance for reducing the mortality of cardiovascular and cerebrovascular diseases.

PH-activated metal–organic layer nanozyme for ferroptosis tumor therapy

Nanozymes have made great achievements in the research of tumor therapy. However, due to the complex tumor microenvironment, the catalytic activity and biosafety of nanozymes are limited. High catalytic efficiency is a relentless pursuit for the preparation of high-performance nanozymes. Dimensional reduction from 3D nanoscale metal–organic frameworks (nMOFs) to 2D nanoscale metal–organic layers (nMOLs) increases the encounters frequency of nanozymes and substrate, which facilitates the diffusion of reactive oxygen species (ROS) from nMOLs, thus significantly improving the effectiveness of chemodynamic therapy. In this study, He@Ce-BTC nMOF and He@Ce-BTB nMOL based on Ce6 SBUs were synthesized by solvothermal reaction. Compared with the 3D nMOFs, the 2D nanozymes He@Ce-BTB nMOL possessed enhanced ROS catalytic efficiency, were able to be activated by the tumor acidic microenvironment with the polymerase mimetic activities (CAT, POD, GSH-OXD) that enhances the lipid peroxidation process and accelerates the process of ferroptosis thereby killing tumor cells. In addition, He@Ce-BTB does not affect normal tissue cells, thus avoiding diffusion-induced side effects. He@Ce-BTB has shown excellent therapeutic effects in vitro and in vivo, which indicates its potential for clinical application, and is expected to become a new generation of drugs for the treatment of tumors.

New mechanistic insights into soil ecological risk assessment of arsenite (III) and arsenate (V)：Cellular and molecular toxicity responses in Eisenia fetida

Inorganic arsenic (iAs) is a persistent bioaccumulation carcinogen that is most abundant in soils in the form of arsenite-As (III) and arsenate-As (V). However, there is currently very little explicit evidence about cytotoxicity of As on soil organisms. Moreover, toxicological data for iAs and proteotoxicity is shortage. The purpose of the present work is to elucidate the cytotoxicity mechanism of As (III) and As (V) to earthworms, a soil ecological sentinel species, and the molecular mechanisms by which As (III)/As (V) directly bind to antioxidative enzyme Cu/Zn-superoxide dismutase (Cu/Zn-SOD). Results indicate that iAs triggered cell membrane injury and genotoxicity. As (V) (56.15%) induced lower cell viability than As (III) (61.88%). Higher ROS and lipid peroxidation level in As (V) support greater cytotoxicity. Differences in cellular uptake due to valence induced diverse levels of oxidative stress and cytotoxicity. At the molecular level, As (III) (129.33%) induced higher Cu/Zn-SOD activity than As (V) (110.75%). Changes in backbone, secondary structure, amino acid microenvironment and particle size of Cu/Zn-SOD further revealed the mechanisms of differential molecular toxicity of As (III) and As (V). Binding reactions with Cu/Zn-SOD explain differences in molecular toxicity. Collective research showed that iAs-induced oxidative stress and binding reactions determine the difference of SOD activity between As (III) and As (V) at the cellular level. This work offers new insights into the health risk assessment of As.

PH sensitive lipid polymeric hybrid nanoparticle (LPHNP) of paclitaxel and curcumin for targeted delivery in breast cancer

Objective The study aimed at designing a pH sensitive Lipid polymeric Hybrid nanoparticle (LPHNP) for targeted release of Paclitaxel (PTX) and Curcumin (CUR) in breast cancer. Significance Such systems shall result in controlled triggered release in acidic microenvironment of tumor cells with improved pharmacokinetic profile. Methods Chitosan-coated CUR and PTX coloaded pH-sensitive LPHNPs were synthesized employing nanoprecipitation technique. The synthesized NPs were characterized in terms of particle size, polydispersity index (PDI), zeta potential, and morphology. Results LPHNPs co-loaded with curcumin (CUR) and paclitaxel (PTX) were successfully formulated, achieving a size of 146 nm, a PDI of 0.18, and an entrapment efficiency exceeding 90%. In vitro release studies demonstrated controlled release of CUR and PTX under tumor pH conditions showing 1.6 fold and 1.7 fold higher release in ABS pH 5 in comparison to PBS 7.4 for PTX and CUR respectively. MTT-assay studies revealed enhanced cytotoxicity of CUR and PTX as LPHNPs showing IC50 value of free CUR & PTX 480.06 µg/mL decreasing to 282.97 µg/mL for CS-CUR-PTX-LPHNPs. In vivo pharmacokinetic evaluations in rats confirmed significantly improved bioavailability, with a 3.8-fold increase in AUC for CUR and a 6.6-fold increase for PTX. Additionally, the LPHNPs demonstrated controlled release and prolonged retention, evidenced by a 2.2-fold increase in the half-life (t1/2) of CUR and a 1.3-fold increase in the half-life of PTX. Conclusions: The results underscores potential of chitosan-coated LPHNP as a promising delivery platform, offering high drug loading, optimal size for cellular penetration, and prolonged blood circulation for cancer.

Tuning the Protonation Sensitivity of Weak Acidic Groups on a Zwitterionic Dendrimer for Selectively Targeting GD2-Overexpressed Tumor Cells in an Acidic Tumor Microenvironment.

Disialoganglioside (GD2) is one of the most popular overexpressed antigens for tumor cell targeting. However, GD2-specific antibodies often show unintended targeting to GD2-expressing health-maintaining cells due to the comparable binding affinities both at physiological pH and in a slightly acidic tumor microenvironment (TME). In this work, an affinity-switchable zwitterionic PAMAM G5 dendrimer (G5-3S) is developed for selective binding to GD2 only in a slightly acidic TME. It has 3 sulfonic groups, 128 carboxylic groups, and 125 amino groups on the surface. This affinity switch is realized by multiple hydrogen bond (H-bond) formation between protonated carboxylic groups surrounding a sulfonic group and overexpressed GD2 clusters on the tumor cell membrane in the slightly acidic TME, whereas there is no stable H-bond formation at physiological pH. Thus, G5-3S shows superior selectivity to GD2-overexpressed tumor cells over anti-GD2 antibodies by avoiding targeting GD2-expressing health-maintaining cells at physiological pH. This suggests that G5-3S is a promising candidate for GD2-overexpressed cancer treatment.

Tumor-derived lactic acid promotes acetylation of histone H3K27 and differentiation of IL-10-producing regulatory B cells through direct and indirect signaling pathways.

Tumor cells are known to enhance glycolysis, even under normoxic conditions, via the Warburg effect, producing excess lactic acid in the tumor microenvironment. Lactic acid enhances the IL-23/IL-17 pathway and induces chronic inflammation. The acidic microenvironment formed by lactic acid suppresses immune cell proliferation and activation. In the present study, we clarified that lactic acid had two novel activities for immune cells. First, lactic acid specifically enhanced acetylation at lysine 27 of histone H3 (H3K27ac) in splenic B cells and monocytes/macrophages, and this epigenetically up-regulates the expression of genes. Acetylation and methylation of other residues of histone H3 were rarely induced. Second, lactic acid induced a particularly-marked enhancement of Il10 gene expression in B cells, leading to an increase in IL-10-producing regulatory B (Breg) cells. Furthermore, two pathways should be involved in both the enhancement of H3K27ac and the induction of Breg cells by lactic acid: a direct pathway that enhances the CD40 signal in B cells, and an indirect pathway that affects B cells by activating the exchange protein directly activated by cAMP (EPAC) 1/2 in non-B cells. In tumor-bearing mice, the levels of H3K27ac of tumor-infiltrating B cells were significantly higher than splenic B cells and were suppressed by intraperitoneal injection of the EPAC1/2 inhibitor. In conclusion, tumor-derived lactic acid increases H3K27ac and IL-10-producing Breg cells, causing the suppression of anti-tumor immunity.

Wearable Multifunctional Hydrogel for Oral Microenvironment Visualized Sensing Coupled with Sonodynamic Bacterial Elimination and Tooth Whitening.

Bacterial-driven dental caries and tooth discoloration are growing concerns as the most common oral health problems. Current diagnostic methods and treatment strategies hardly allow simultaneous early detection and non-invasive treatment of these oral diseases. Herein, a wearable multifunctional double network hydrogel combined with polyaniline and barium titanate (PANI@BTO) nanoparticles is developed for oral microenvironment visualized sensing and sonodynamic therapy. Due to the colorimetric properties of polyaniline, the hydrogel displays a highly sensitive and selective response for visualized sensing of oral acidic microenvironment. Meanwhile, the barium titanate in the hydrogel efficiently generates reactive oxygen species (ROS) under ultrasound irradiation, realizing non-invasive treatment in the oral cavity. Through bacterial elimination experiments and tooth whitening studies, the hydrogel can achieve the dual effect of effectively inhibiting the growth of cariogenic bacteria and degrading tooth surface pigments. Owing to the visualized sensing of the oral acidic microenvironment and efficient sonodynamic therapy function, the proposed hydrogel system offers a solution for the prevention of caries and tooth whitening, which is promising in developing the biomedical system targeting the simultaneous sensing and therapy for oral diseases.

Dynamic pH‐Responsive Release and Biological Impact of In‐Situ Quercetin‐Modified MIL‐101(Fe)‐NH2

A successful investigation was conducted on the in‐situ modification of MIL‐101(Fe)‐NH2 with quercetin and its controlled release under various pH conditions. MIL‐101(Fe)‐NH2 was synthesized using an electrochemical method at room temperature (15 volts, 30 minutes). The formation of the material was confirmed through comprehensive analyses, including PXRD, FTIR, and TGA. Nitrogen sorption isotherm measurements revealed that Qu@MIL‐101(Fe)‐NH2 exhibited a smaller surface area compared to MIL‐101(Fe)‐NH2, with both materials classified as mesoporous. Transmission electron microscopy (TEM) clearly depicted the materials' octahedral microspindle morphology. The cumulative percent release (CPR) of quercetin from Qu@MIL‐101(Fe)‐NH2 over 72 hours was determined to be 53.45% at pH 1.2, 19.48% at pH 4.8, and 5.87% at pH 7.4. Notably, quercetin release in the acidic microenvironment representative of cancer cells (pH 4.8) was nearly four times higher than under physiological conditions (pH 7.4). Kinetic release studies indicated that quercetin release from Qu@MIL‐101(Fe)‐NH2 followed the Ritger‐Peppas kinetic model, suggesting non‐Fickian diffusion. The MIL‐101(Fe)‐NH2 nanocarriers, with in‐situ‐loaded quercetin, demonstrated promising potential for pH‐triggered drug release. Additionally, the safety of MIL‐101(Fe)‐NH2 in biological models and the anticancer efficacy of quercetin were evaluated in vitro using two liver cancer cell lines.