Tumor-specific Targeting Research Articles

Single-cell RNA-seq-based proteogenomics identifies glioblastoma-specific transposable elements encoding HLA-I-presented peptides.

We analyze transposable elements (TEs) in glioblastoma (GBM) patients using a proteogenomic pipeline that combines single-cell transcriptomics, bulk RNA sequencing (RNA-seq) samples from tumors and healthy-tissue cohorts, and immunopeptidomic samples. We thus identify 370 human leukocyte antigen (HLA)-I-bound peptides encoded by TEs differentially expressed in GBM. Some of the peptides are encoded by repeat sequences from intact open reading frames (ORFs) present in up to several hundred TEs from recent long interspersed nuclear element (LINE)-1, long terminal repeat (LTR), and SVA subfamilies. Other HLA-I-bound peptides are encoded by single copies of TEs from old subfamilies that are expressed recurrently in GBM tumors and not expressed, or very infrequently and at low levels, in healthy tissues (including brain). These peptide-coding, GBM-specific, highly recurrent TEs represent potential tumor-specific targets for cancer immunotherapies.

BASECAMP-1: Leveraging human leukocyte antigen (HLA) loss of heterozygosity (LOH) in solid tumors by next-generation sequencing (NGS) to identify patients with relapsed solid tumor for future logic-gated Tmod CAR T-cell therapy.

TPS2676 Background: Solid tumors comprise > 90% of cancers. Metastatic colorectal cancer, non-small cell lung cancer, and pancreatic cancer are among the leading causes of cancer-related mortality (5-year overall survival: 14%, 6%, and 3%, respectively) (ACS. 2021). Chimeric antigen receptor (CAR) T-cell therapy has demonstrated clinical efficacy in hematologic malignancies (Neelapu S. et al. N Engl J Med. 2017). Translating engineered T-cell therapies to solid tumors has proven to be challenging due to a lack of tumor-specific targets that can discriminate cancer cells from normal cells. Previous studies using carcinoembryonic antigen (CEA) T-cell receptors and mesothelin (MSLN) CARs resulted in dose-limiting on-target, off-tumor toxicities (Parkhurst M, et al. Mol Ther. 2011; Tanyi J. Cellicon Valley '21). To create a therapeutic safety window, Tmod CAR T-cell therapy utilizes dual-signaling receptors to create a robust NOT logic gate capable of killing tumor cells, while leaving healthy cells intact (Hamburger A, et al. Mol Immunol. 2020). The 2 receptors in Tmod CAR T-cell therapy comprise an activator that recognizes an antigen on the surface of tumor cells that may also be present on normal cells, such as CEA and MSLN, and a blocker that recognizes a second surface antigen from an allele lost only in tumor cells. The frequency of HLA LOH among advanced GI solid tumor cancers in the Tempus real-world dataset is 16.3% with a range of 15.6%-20.8% between colorectal, pancreatic, and gastroesophageal tumors (Hecht R. et al. ASCO-GI 2022. Abstract #190). As such, HLA LOH offers a definitive tumor versus normal discriminator target for CAR T-cell therapy. Different activator/blocker combinations can be engineered with the Tmod platform technology and may be applied to T cells and natural killer cells in autologous and allogeneic settings. BASECAMP-1 is a currently enrolling observational study with key objectives of 1) To identify patients with somatic HLA LOH eligible for Tmod CAR T-cell therapy, and 2) To obtain leukapheresis and feasibility for the future EVEREST Tmod CAR T-cell trial. Methods: BASECAMP-1 (NCT04981119) patient eligibility has 2 parts: 1) Patients will be initially screened to identify germline HLA-A*02 heterozygosity by central NGS. If HLA-A*02 heterozygosity is confirmed, primary archival tumor tissue will be analyzed for somatic mutations by xT-Onco NGS testing. 2) If the tumor demonstrates HLA-A*02 LOH and the patient is eligible after screening, the patient will undergo leukapheresis. Banked T cells will be available for the autologous EVEREST Tmod CAR T-cell therapy interventional study to reduce waiting time at relapse. Clinical trial information: NCT04981119.

Fluorescent Anti-CEA Nanobody for Rapid Tumor-Targeting and Imaging in Mouse Models of Pancreatic Cancer.

Tumor-specific targeting with fluorescent probes can enhance contrast for identification of cancer during surgical resection and visualize otherwise invisible tumor margins. Nanobodies are the smallest naturally-occurring antigen-binding molecules with rapid pharmacokinetics. The present work demonstrates the efficacy of a fluorescent anti-CEA nanobody conjugated to an IR800 dye to target and label patient derived pancreatic cancer xenografts. After intravenous administration, the probe rapidly localized to the pancreatic cancer tumors within an hour and had a tumor-to-background ratio of 2.0 by 3 h. The fluorescence signal was durable over a prolonged period of time. With the rapid kinetics afforded by fluorescent nanobodies, both targeting and imaging can be performed on the same day as surgery.

Macrophage-mediated tumor-targeted delivery of engineered Salmonella typhimurium VNP20009 in anti-PD1 therapy against melanoma

Bacterial antitumor therapy has great application potential given its unique characteristics, including genetic manipulation, tumor targeting specificity and immune system modulation. However, the nonnegligible side effects and limited efficacy of clinical treatment limit their biomedical applications. Engineered bacteria for therapeutic applications ideally need to avoid their accumulation in normal organs and possess potent antitumor activity. Here, we show that macrophage-mediated tumor-targeted delivery of Salmonella typhimurium VNP20009 can effectively reduce the toxicity caused by administrating VNP20009 alone in a melanoma mouse model. This benefits from tumor-induced chemotaxis for macrophages combined with their slow release of loaded strains. Inspired by changes in the tumor microenvironment, including a decrease in intratumoral dysfunctional CD8+ T cells and an increase in PDL1 on the tumor cell surface, macrophages were loaded with the engineered strain VNP-PD1nb, which can express and secrete anti-PD1 nanoantibodies after they are released from macrophages. This novel triple-combined immunotherapy significantly inhibited melanoma tumors by reactivating the tumor microenvironment by increasing immune cell infiltration, inhibiting tumor cell proliferation, remodeling TAMs to an M1-like phenotype and prominently activating CD8+ T cells. These data suggest that novel combination immunotherapy is expected to be a breakthrough relative to single immunotherapy.

Hypoxia-responsive hyaluronic acid nanogels with improved endo/lysosomal escape ability for tumor-targeted cytochrome c delivery

An ideal protein therapeutic effect depends on the protein drug-carrying nanocarrier to achieve high loading efficiency, excellent systemic stability, specific tumor targeting, rapid endo/lysosomal escape, and controlled protein release behavior. Herein, novel and interesting hypoxia-responsive nanogels with improved endo/lysosomal escape ability are reported in this work for tumor-targeted protein delivery. These nanogels can encapsulate a cationic protein, cytochrome C (CC), inside their cores with good stability in various media and thus protect the protein from degradation during blood circulation. In this nanogel system, monomethoxy poly(ethylene glycol) (mPEG) is conjugated to hyaluronic acid (HA) and serves as an outer shell for improving stability of the nanostructure, and the anionic HA is employed for encapsulation of cationic CC through multiphysical interactions with a high loading efficiency. The nanogel system is crosslinked using a hypoxia-responsive crosslinker for subsequent triggered release of CC. Due to presence of the hypoxia-responsive crosslinker, more than 80% of the loaded CC can be released within 24 h under hypoxic conditions. The in vitro experimental results demonstrate that these nanogels can effectively deliver CC into cancer cells via CD44-mediated tumor targeting, subsequently enable rapid endo/lysosomal escape, and trigger CC release under hypoxic conditions. In addition, cytotoxicity test confirms that the CC-loaded nanogels exhibit much higher cytotoxicity to cancer cells at hypoxic condition than that at normoxic condition, which indicates that this nano-platform is a promising candidate for tumor-targeting protein delivery and efficient cancer therapy.

ITGA4 knockout prevents blood-brain-barrier migration of chimeric antigen receptor T cells

Abstract Chimeric Antigen Receptor (CAR) T cells have shown remarkable anti-tumor activity in various B cell malignancies. However, expanding their use to solid tumors has proven difficult due to the lack of sufficiently tumor-specific target antigens. Restricting CAR T cells from trafficking to certain healthy tissues showing shared expression of an otherwise tumor-specific target antigen may open up new avenues to the treatment of solid tumors with CAR T cells. We developed an electroporation-based CRISPR/Cas9 approach targeting integrin a4 (ITGA4), a key component of the T cell adhesion heterodimer VLA-4 required for blood-brain-barrier migration via the endothelial adhesion protein VCAM-1. We characterize ITGA4 knockout kinetics in human T cells by flow cytometry, determine its effect on T cell adhesion to VCAM-1 using a custom in vitro adhesion assay, determine tissue distribution of ITGA4ko cells in a mouse model and characterize the anti-tumor activity of ITGA4ko CAR T cells using a luminescence-based cytotoxicity assay. Near-complete ITGA4 knockout could be achieved during a standard 12-day CAR T cell production process and significantly decreased adhesion of human T cells to VCAM-1. ITGA4ko T cells appeared to be efficiently redirected from the brain to the bone marrow which was validated by flow cytometry showing almost a complete lack of T cells in the brain after ITGA4 knockout. Importantly, knockout did not significantly change CAR T cell expansion or anti-tumor activity. In conclusion, we show that ITGA4 knockout is feasible, results in efficient exclusion of T cells from the brain without affecting CAR T cell function, representing a promising approach to shape CAR T cell selectivity for the treatment of solid tumors.

Tumor Customized 2D Supramolecular Nanodiscs for Ultralong Tumor Retention and Precise Photothermal Therapy of Highly Heterogeneous Cancers.

Target therapy for highly heterogeneous cancers represents a major clinical challenge due to the lack of recurrent therapeutic targets identified in these tumors. Herein, the authors report a tumor-customized targeting photothermal therapy (PTT) strategy for highly heterogeneous cancers, by which 2D supramolecular self-assembled nanodiscs are modified with tumor-specific binding peptides identified by phage display techniques. Taking osteosarcoma (OS) as a model heterogeneous cancer, an OS targeting peptide (OTP) is first selected after biopanning and is demonstrated to successfully bind to this heterogeneous cancer cells/tissues. Successful conjugation of OTP to heptamethine cyanine (Cy7)-based 2D nanodiscs Cy7-TCF (2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran,TCF) enables the 2D nanodiscs to specifically target the heterogeneous tumor. Notably, a single dose injection of this targeted nanodisc (T-ND) not only effectively induces enhanced photothermal tumor ablation under near-infrared light, but also exhibits sevenfold increase of tumor retention time (more than 24days) compared to generic nanomedicine. Thus, the authors' findings suggest that the combination of phage display-based affinity peptides selection and 2D supramolecular nanodiscs leads to the development of a platform technology for highly heterogeneous cancers precise therapy, offering specific tumor targeting, ultralong tumor retention, and precise PTT.

Advances in CAR-T cell therapy for malignant solid tumors.

T cells modified by chimeric antigen receptor (CAR) have the advantage of major histocompatibility complex-independent recognition of tumor-associated antigens, so can achieve efficient response to tumor targets. Chimeric antigen receptor (CAR) T cell therapy has shown a good therapeutic effect in hematological malignancies; however, its efficacy is generally not satisfactory for solid tumors. The reasons include the lack of tumor specific antigen target on solid tumors, the uncertainty of homing ability of engineered T cells and the inhibitory immune microenvironment of tumors. In clinical trials, the targets of CAR-T cell therapy for solid tumors are mainly disialoganglioside (GD2), claudin-18 isoform 2 (CLDN18.2), mesenchymal, B7 homolog 3 (B7H3), glypican (GPC) 3 and epidermal growth factor receptor variant Ш (EGFRvШ)Ⅲ. Combination of CAR-T cells with oncolytic viruses, tyrosine kinase inhibitors, and programmed death ligand-1 monoclonal antibodies may increase its efficacy. The CAR-T cell therapy for solid tumors can be optimized through gene editing to enhance the activity of CAR-T cells, adding corresponding regulatory components to make the activation of CAR-T cells safer and more controllable, and enhancing the persistence of CAR-T cells. In this article, we review the latest advances of CAR-T cell therapy in solid tumors to provide new insights for clinical application.

Robust In Vitro Pharmacology of Tmod, a Synthetic Dual-Signal Integrator for Cancer Cell Therapy.

Progress toward improved solid-tumor treatment has long been hindered by the lack of truly tumor-specific targets. We have developed an approach to T cell therapy based on a dual-receptor system called Tmod™ that addresses this problem. The Tmod system exploits one of the few common genetic differences between tumor and normal cells: loss of heterozygosity (LOH). It utilizes the basic mechanistic logic that evolved in early vertebrates to mediate self vs. non-self discrimination, where an activation stimulus is blocked by self-ligands. Tmod constructs employ a chimeric antigen receptor (CAR) or T cell receptor (TCR) as activator component and a modified LIR-1 inhibitory receptor (blocker) to achieve high selectivity based on expression of the blocker antigen (Ag). Here we explore the in vitro pharmacology of a blocker directed at the HLA-A*02 Ag paired with either a mesothelin CAR or an HLA-A*11-restricted KRAS peptide TCR. While more sensitive to receptor expression changes on effector cells, we show that Tmod response is well-buffered against variations in Ag levels on target cells. In addition, the data reveal at least two distinguishable pharmacologic mechanisms of Tmod blocker function: (1) reducing activator sensitivity and (2) decreasing activation magnitude.

Engineered Cell‐Derived Vesicles Displaying Targeting Peptide and Functionalized with Nanocarriers for Therapeutic microRNA Delivery to Triple‐Negative Breast Cancer in Mice (Adv. Healthcare Mater. 5/2022)

Extracellular Vesicles — A Versatile Biomaterial In article number 2101387 Rajendran J. C. Bose and co-workers demonstrate an effective anticancer therapy by developing PLGA-nanocarriers loaded with antimiRNA-21 or antimiRNA-10b using engineered tumor cell derived extracellular vesicles (eEVs) that display tumor specific receptor targeting peptide to achieve therapeutic effect by reprogramming cancer cells.

T cell receptor engineering of primary NK cells to therapeutically target tumors and tumor immune evasion

BackgroundT cell receptor (TCR)-engineered cells can be powerful tools in the treatment of malignancies. However, tumor resistance by Human Leukocyte antigen (HLA) class I downregulation can negatively impact the success...

GRP78-targeted and doxorubicin-loaded nanodroplets combined with ultrasound: a potential novel theranostics for castration-resistant prostate cancer

The construction of multifunctional oncotherapy nanoplatforms that combine diagnosis and treatment remains challenging. Nanodroplets (NDs), which simultaneously enhance ultrasound imaging and therapeutic effects, are a potential strategy for non-invasive drug delivery. To achieve the goals of precise medicine, novel SP94 peptide-modified and doxorubicin-loaded ultrasonic NDs (SP94-DOX-NDs) for castration-resistant prostate cancer (CRPC) targeting and treatment were constructed in this study. The characteristics, contrast-enhanced ultrasound imaging (CEUI), targeting ability to glucose-regulated protein 78 (GRP78)-overexpressing CRPC and anticancer effect of the SP94-DOX-NDs were assessed. The desired SP94-NDs were successfully prepared using the nanoemulsification method using a certain proportion of SP94-PEG-chitosan, perfluoropentane (PFP), Tween 20, and lecithin. SP94-NDs with a size of ∼300 nm showed great biocompatibility and CEUI ability. Compared with blank NDs, SP94-NDs exhibited higher tumor-specific targeting ability due to conjugation between the SP94 peptide and GRP78-overexpressing 22RV1 cells. Most importantly, in vitro and in vivo investigations showed that SP94-DOX-NDs combined with ultrasound could specifically deliver DOX into 22RV1 cells and thereby demonstrated a stronger anticancer effect than DOX-NDs and DOX. Thus, SP94-DOX-NDs may provide an efficient approach for the real-time imaging of tumors and triggered, accurate drug delivery to tumors.

NIR-II imaging of hepatocellular carcinoma based on a humanized anti-GPC3 antibody.

Liver cancer, of which hepatocellular carcinoma (HCC) is the most common form, is one of the most lethal cancers worldwide. The five-year survival rate for HCC is below 9%, which can be attributed to late diagnosis and limited treatment options at the late stage. Therefore, safe and efficient imaging strategies are urgently needed to facilitate HCC diagnosis and stage evaluation. The development of the second near infrared window (NIR-II, 1000-1700 nm) fluorescence imaging offers the advantages of enhanced resolutions, deeper penetration depth, and less autofluorescence compared to traditional NIR-I window (700-900 nm) imaging. Herein, an HCC targeted NIR-II fluorescent probe, GPC-ICG, was developed by labelling a humanized anti-GPC3 monoclonal antibody with indocyanine green (ICG). Compared to the negative control IgG-ICG probe, the GPC3-ICG probe demonstrated specific GPC3 targeting capability in vitro. And for GPC3 positive Huh-7 tumor bearing mice, the GPC3-ICG probe specifically accumulated in subcutaneous xenografts, with a tumor-background ratio (TBR) of up to 3. The NIR-II imaging of mice organs ex vivo also indicated that GPC3-ICG specifically targeted Huh-7 tumor tissue. Overall, GPC3-ICG is a promising NIR-II probe for GPC3 targeted imaging of HCC.

Receptor-Targeted Surface-Engineered Nanomaterials for Breast Cancer Imaging and Theranostic Applications.

Breast cancer is one of the most frequently diagnosed cancers in women and the major cause of worldwide cancer-related deaths among women. Various treatment strategies including conventional chemotherapy, immunotherapy, gene therapy, gene silencing and deliberately engineered nanomaterials for receptor mediated targeted delivery of anticancer drugs, antibodies, and small-molecule inhibitors, etc are being investigated by scientists to combat breast cancer. Smartly designed/fabricated nanomaterials are being explored to target breast cancer through enhanced permeation and retention effect; and also, being conjugated with suitable ligand for receptor-mediated endocytosis to target breast cancer for diagnostic, and theranostic applications. These receptor-targeted nanomedicines have shown efficacy to target specific tumor tissue/cells abstaining the healthy tissues/cells from cytotoxic effect of anticancer drug molecules. In the last few decades, theranostic nanomedicines have gained much attention among other nanoparticle systems due to their unique ability to deliver chemotherapeutic as well as diagnostic agents, simultaneously. Theranostic nanomaterials are emerging as novel paradigm with ability for concurrent delivery of imaging (with contrasting agents), targeting (with biomarkers), and anticancer therapeutics with one delivery system (as cancer theranostics) and can transpire as promising strategy to overcome various hurdles for effective management of breast cancer including its most aggressive form, triple-negative breast cancer.

TME-targeting theranostic agent uses NIR tracking for tumor diagnosis and surgical resection and acts as chemotherapeutic showing enhanced efficiency and minimal toxicity.

Rationale: Precise diagnosis and effective therapy of the tumor microenvironment (TME) remains a challenge. Fluorescence tracers for monitoring primary tumors are currently reported; however, they face challenges in accurately delineating tumors in real-time during surgery, including interference from the background and insufficient accumulation of imaging reagents at tumor sites. Additionally, although the natural product podophyllotoxin (PPT) had potent and broad anti-tumor activity, the poor tumor target specificity and high toxicity of PPT extremely limited its clinical application.Methods: In the current study, a novel theranostic agent PBB was designed and synthesized by coupling the natural chemotherapeutic drug PPT with a near-infrared (NIR) fluorescence probe hemicyanine (CyOH) via redox-responsive thiolactate linker and introducing biotin to CyOH to enhance the active target ability. The activation mechanism of PBB was characterized by absorption spectra, fluorescence spectra, and HPLC. Subsequently, we investigated its imaging action, anti-tumor activity, and toxicity in vitro and in vivo.Results: In vitro experiments, PBB was verified to possess a ROS/GSH-responsive molecular switch, impelling PBB to release a fluorescent fragment and active drug PPT and selectively lighting up tumor cells but not the normal cells. As such, PBB was demonstrated to selectively inhibit the growth of tumor cells by inducing intracellular accumulation of ROS and MMP depolarization. More importantly, PBB significantly suppressed hepatic tumor growth and minimized the adverse effects caused by PPT, including acute toxicity and impaired liver function. Finally, the NIR fluorescence accumulated in the tumor tissue and stayed continuous for over 24h, and PBB provided precise visualization and highly selective fluorescence diagnosis to guide tumor resection.Conclusions: Therefore, the multilevel targeting theranostic agent provided a novel tool for precise diagnosis, real-time monitoring, and efficient tumor chemotherapy with high safety.

Charge reversal hairpin peptide modified synergy therapeutic nanoplatforms for tumor specific drug shuttling.

Given the distinct pathological features of neoplasm tissues, multifunctional responsive nanocarriers have been recently considered as promising candidates to optimize the chemotherapy regime. As a result, we propose a graphene oxide-based pH-responsive drug delivery system via covalent assembly of "hairpin-like" cell penetrating peptides with acid sensitive and charge reversal properties to realize superior tumor specificity and lower toxicity. Graphene oxide here can serve as high doxorubicin-loading nanosheets and facilitate swift drug release in response to laser irradiation, which provides an efficient platform for the synergy of photo-chemotherapy. Structurally, polyglycol conjugation on the graphene oxide surface fulfils the function of nanocomposite stabilization. After administration, the elaborately acid sensitive cell penetrating peptides maintain the hairpin structure under physiological conditions, while after entering the tumor acidic microenvironment, they undergo charge reversal and structural conversion to promote the cellular uptake of nanoparticles. The evaluation of nanocomposites in vitro revealed their negligible systematic toxicity and remarkable antitumor effects. In vivo experiments also confirmed the impressive stability and tumor-specific targeting for alleviating breast cancer. In conclusion, hairpin peptide modified graphene oxide nanoparticles show multiple merits including high drug carrying capacity, selective tumor penetration, responsive drug release and effective combination oncotherapy.

Single-molecule photosensitizers for NIR-II fluorescence and photoacoustic imaging guided precise anticancer phototherapy.

It is ideal yet challenging to achieve precise tumor targeting and high-quality imaging guided combined photodynamic and photothermal therapy (PDT and PTT). In this study, we synthesized a series of D–π–A-type single-molecule photosensitizers (CyE-TT, CyQN-TT, and CyQN-BTT) based on quaternized 1,1,2-trimethyl-1H-benz[e]indoles as acceptors by introducing π-bridges to elongate their emission wavelength and triphenylamine as a donor to construct a twisted molecular conformation. We found that the 1O2 generation ability and the photothermal conversion efficiency (PCE) are directly correlated with the π-bridge between donors and acceptors in these molecules. When a 2,1,3-benzothiadiazole group as a π-bridge was introduced into CyQN-BTT, the singlet oxygen yield enhanced to 27.1%, PCE to 37.8%, and the emission wavelength was red-shifted to near-infrared II (NIR-II). Importantly, double-cationic CyQN-BTT displays structure-inherent cancer cell targeting ability instead of targeting normal cells. Consequently, relying on NIR-II fluorescence imaging (NIR-II FLI) and photoacoustic imaging (PAI) guided PDT and PTT, CyQN-BTT can accurately locate solid tumors in mice and effectively eliminate them with good biocompatibility and biosafety to normal tissues. This study provides insights into the design and development of a tumor-specific targeting multifunctional photosensitizer for precise cancer phototherapy.

Conditionally Activatable Photoredox Catalysis in Living Systems.

The transformational effect of photoredox catalytic chemistries has inspired new opportunities, enabling us to interrogate nature in ways that are not possible otherwise and to unveil new biotechnologies in therapy and diagnosis. However, the deployment of artificial photoredox catalysis in living systems remains challenging, mired by the off-target risk and safety concerns of photocatalyst toxicity. Here, we present an appealing approach, namely conditionally activatable photoredox catalysis (ConAPC), and as a proof of concept design the first ConAPC architecture (Se-NO2) based upon classic self-immolative chemistry, in which the inherent photocatalytic properties can be temporarily caged while the species becomes active only at the tumor sites via sensing to specific biomarkers. Such a masking strategy allows a spatial-temporal control of photoresponsivity in vitro and in vivo. In particular, for ConAPC design, a new biologically benign metal-free photocatalyst (Se-NH2), which is able to initiate NIR photoredox catalysis to manipulate the cellular electron pool in an O2-independent mechanism of action, is identified. With this unique strategy, potent tumor-specific targeting photocatalytic eradication (TGI: 95%) is obtained in a mouse model. Impressively, favorable features such as high-resolution tumor recognition (SBR: 33.6) and excellent biocompatibility and safety are also achieved. This work therefore offers a new possibility for chemists to leverage artificial photocatalytic reactions toward the development of facile and intelligent photocatalytic theranostics.

Dissecting the Oncogenic Roles of Keratin 17 in the Hallmarks of Cancer

There is an unmet need to identify and validate tumor-specific therapeutic targets to enable more effective treatments for cancer. Heterogeneity in patient clinical characteristics as well as biological and genetic features of tumors present major challenges for the optimization of therapeutic interventions, including the development of novel and more effective precision medicine. The expression of keratin 17 (K17) is a hallmark of the most aggressive forms of cancer across a wide range of anatomical sites and histological types. K17 correlates with shorter patient survival, predicts resistance to specific chemotherapeutic agents, and harbors functional domains that suggest it could be therapeutically targeted. Here, we explore the role of K17 in the hallmarks of cancer and summarize evidence to date for K17-mediated mechanisms involved in each hallmark, elucidating functional roles that warrant further investigation to guide the development of novel therapeutic strategies.

Glutathione-Responsive Chemodynamic Therapy of Manganese(III/IV) Cluster Nanoparticles Enhanced by Electrochemical Stimulation via Oxidative Stress Pathway.

Escalating the level of reactive oxygen species (ROS) in a tumor microenvironment is one of the effective strategies to improve the efficacy of anticancer therapy. In this work, manganese cluster nanoparticles (Mn12) encapsulated with heparin (Mn12-heparin) were developed as a chemodynamic therapeutic agent for cancer treatment by raising ROS levels in tumor cells via cascade reactions. The manganese cluster is a cluster of mixed valence (III/IV) with acetate as the ligand. The cluster is readily subject to reduction by glutathione (GSH) to release Mn(II), which reacts with H2O2 to generate hydroxyl radicals via a Fenton-like pathway. The generation of hydroxyl radicals could be enhanced by the stimulation of an external alternative electric field during which GSH acts as an electron mediator to enhance the release of Mn(II) from the cluster. The relatively high levels of both H2O2 and GSH and the acidic environment in tumor cells strengthen its specificity when the manganese cluster system is employed to suppress or eliminate tumors. Both in vitro and in vivo results suggest that, in addition to the cytotoxicity imposed by the raised ROS level due to the presence of Mn(II) species, the depletion of endogenous GSH leads indirectly to the inhibition of glutathione peroxidase 4 (GPX4), consequently raising the lipid peroxidation (LPO) level to cause ferroptosis. The apoptosis and ferroptosis jointly render the manganese-based agent potent efficacy with tumor-targeting specificity in antitumor treatment under electric stimulation.