Raddeanin A Enhances Mitochondrial DNA-cGAS/STING Axis-Mediated Antitumor Immunity by Targeting Transactive Responsive DNA-Binding Protein 43

Polyvalent folate receptor-targeting chimeras for degradation of membrane proteins

Lysosome-targeting chimeras (LYTACs) represent a revolutionary targeted protein degradation technology. However, the advancement of LYTACs faces substantial challenges due to the limited diversity of lysosome-trafficking receptors. In this study, we identified folate receptor α (FRα) as a new class of lysosome-trafficking receptors capable of facilitating the degradation of membrane proteins. Leveraging a polyvalent crosslinking strategy, we developed FRα-targeting chimeras (FRTACs), including enhanced green fluorescent protein-targeting FR-Ctx and PD-L1-targeting FR-Atz. The optimized FRTACs demonstrated subnanomolar potency in eliminating cell-surface targets, with efficacy dependent on both FRα expression and lysosomal activity. Specifically, FR-Ctx inhibited cancer cell proliferation, while FR-Atz enhanced T cell-mediated cytotoxicity against tumor cells. FR-Atz exhibited robust PD-L1 degradation efficiency in vivo and elicited tumor-specific immune responses by reprogramming the tumor microenvironment from an immunosuppressive to an immunostimulatory state in both RM-1 and humanized B16F10 mouse models. These findings establish FRTACs as a promising platform for the design of tumor-targeting LYTACs.

Novel Quaternary Ammonium Salt-Linked STING Agonist Antibody-Drug Conjugate: Synergistic Activation of Tumor Immunity with Mitigated Off-Target Toxicity

Immune-stimulating antibody conjugate (ISACs) incorporating STING agonists as payloads leverage both the targeting capability of the Fab region and the Fc region-mediated tumor antigen-dependent immune activation. Herein, a novel class of ISACs is reported, generated by engineering a quaternary ammonium-cleavable linker to conjugate diABZI STING agonist 3 (dSA3) with the HER2-targeting antibody Trastuzumab. The optimized ISAC (TZ-dSA3-12) demonstrated high potency, stability, enhanced solubility, and reduced off-target toxicity. The data showed that TZ-dSA3-12 potently activates the STING pathway in the tumor microenvironment through the synergistic action of the Fab and Fc regions of antibodies (activity switch-on). In contrast, TZ-dSA3-12 exhibited ≈75 fold lower activity than dSA3 in normal immune cells, where activation relies solely on the Fc region without Fab-mediated tumor antigen binding (activity switch-off). Furthermore, systemic administration of TZ-dSA3-12 at a dose (1 mg kg-1) elicited robust and sustained antitumor effect in a manner dependent on the activation of innate immunity and adaptive immunity, including macrophages, dendritic cells (DCs) and CD8+ T cells, while minimizing systemic cytokine release. Notably, TZ-dSA3-12 also induced immunological memory to combat the growth of rechallenged tumors. This innovative quaternary ammonium-linked STING agonist-ISAC represents a promising avenue for the future development of STING-targeted immunotherapy.

Nano-immunomodulator amplifies STING activation in tumor-associated macrophages for cancer immunotherapy

The initiation of tumor-specific T cell responses is critically dependent on antigen-presenting cells (APCs). Nevertheless, as the most dominant APCs in tumors, M2-like macrophages largely restrained T cell activation due to inefficient antigen cross-presentation. Herein, we rationally designed a nano-immunomodulator (FANP) to restore the antigen presentation capability of M2-like macrophages by amplifying stimulator of interferon genes (STING) activation. FANPs were fabricated by self-assembly of Fe3+ and Raddeanin A (RA), which rapidly degraded when reaching tumor microenvironment. The released Fe3+ induced the polarization of M2-like macrophages into M1 phenotype, followed by RA stimulation for amplified STING activation, allowing robust antigen cross-presentation and T cell-driven anti-tumor response, leading to effective tumor regression in both immunogenic and poor-immunogenic tumor models. Notably, FANPs exhibited intensive STING activation in human tumor samples, showing potential for clinical impact. Our work offers a simple and robust strategy to re-educate M2-like macrophages by augmenting STING activation for cancer immunotherapy.

Recent advances in target identification technology of natural products

Natural products, characterized by their structural diversity, broad spectrum of biological activities, and safe yet effective therapeutic potential, have become pivotal resources in drug research and development. However, the target proteins of many natural products remain unidentified, a significant challenge that impedes their development into viable drug candidates. Therefore, the target identification is crucial for elucidating the pharmacological mechanisms of natural products and facilitating their therapeutic applications. In this review, we present a comprehensive overview of recent advancements in methodologies for target identification of natural products. Additionally, we predict future developments in new technologies for target discovery. Collectively, this review establishes a methodological framework for uncovering the cellular targets and pharmacological mechanisms of natural products, thereby advancing the development of innovative natural product-based drugs.

Engineered NK Exosomes Captured Antigens In Situ for Enhanced Tumor Immunotherapy

Natural killer (NK) cells are widely involved in the field of tumor immunotherapy due to their unique killing ability. However, the durability and efficacy of NK-cell monotherapy are facing great challenges owing to the limitation of immunosuppressive tumor microenvironment (TME). NK cell-derived exosomes (Neo) not only play an innate immunomodulatory role similar to NK cells but also emerge as promising antitumor nanocarriers. In this study, an engineered Neo (R@Neo-MN) was designed that encapsulates the multifunctional antitumor drug (Raddeanin a, RA) and modified with maleimide (Mal, M) and mannose (Man, N). The obtained R@Neo-MN could not only exert NK cell-like antitumor function but also induce the immunogenic cell death of tumors to release tumor-associated antigens (TAAs). Furthermore, R@Neo-MN activated the cyclic guanosine monophosphate-adenosine monophosphate synthase/interferon gene stimulator (cGAS/STING) to release type I interferons (IFN). Then, R@Neo-MN could capture TAAs through Mal and specifically target dendritic cells (DCs) through Man, thereby promoting the maturation of DCs and enhancing tumor-specific cytotoxic T-cell (CTL)-mediated adaptive immunity. The released IFN further promoted the infiltration and activition of NK cells and CTLs at the tumor site. Our study suggested a novel strategy that harnesses both innate and adaptive immunity for enhanced tumor immunotherapy.

Immunogenic Cell Death and Metabolic Reprogramming in Cancer: Mechanisms, Synergies, and Innovative Therapeutic Strategies

Immunogenic cell death (ICD) is a promising cancer therapy where dying tumor cells release damage-associated molecular patterns (DAMPs) to activate immune responses. Recent research highlights the critical role of metabolic reprogramming in tumor cells, including the Warburg effect, oxidative stress, and lipid metabolism, in modulating ICD and shaping the immune microenvironment. These metabolic changes enhance immune activation, making tumors more susceptible to immune surveillance. This review explores the molecular mechanisms linking ICD and metabolism, including mitochondrial oxidative stress, endoplasmic reticulum (ER) stress, and ferroptosis. It also discusses innovative therapeutic strategies, such as personalized combination therapies, metabolic inhibitors, and targeted delivery systems, to improve ICD efficacy. The future of cancer immunotherapy lies in integrating metabolic reprogramming and immune activation to overcome tumor immune evasion, with multi-omics approaches and microbiome modulation offering new avenues for enhanced treatment outcomes.

Bidirectional regulation of the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon gene pathway and its impact on hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) ranks as the fourth leading cause of cancer-related deaths in China, and the treatment options are limited. The cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) activates the stimulator of interferon gene (STING) signaling pathway as a crucial immune response pathway in the cytoplasm, which detects cytoplasmic DNA to regulate innate and adaptive immune responses. As a potential therapeutic target, cGAS-STING pathway markedly inhibits tumor cell proliferation and metastasis, with its activation being particularly relevant in HCC. However, prolonged pathway activation may lead to an immunosuppressive tumor microenvironment, which fostering the invasion or metastasis of liver tumor cells.

AIM

To investigate the dual-regulation mechanism of cGAS-STING in HCC.

METHODS

This review was conducted according to the PRISMA guidelines. The study conducted a comprehensive search for articles related to HCC on PubMed and Web of Science databases. Through rigorous screening and meticulous analysis of the retrieved literature, the research aimed to summarize and elucidate the impact of the cGAS-STING pathway on HCC tumors.

RESULTS

All authors collaboratively selected studies for inclusion, extracted data, and the initial search of online databases yielded 1445 studies. After removing duplicates, the remaining 964 records were screened. Ultimately, 55 articles met the inclusion criteria and were included in this review.

CONCLUSION

Acute inflammation can have a few inhibitory effects on cancer, while chronic inflammation generally promotes its progression. Extended cGAS-STING pathway activation will result in a suppressive tumor microenvironment.

Nanocarrier-mediated modulation of cGAS-STING signaling pathway to disrupt tumor microenvironment

The cGAS-STING signaling plays an important role in the immune response in a tumor microenvironment (TME) of triple-negative breast cancer (TNBC). The acute and controlled activation of cGAS-STING signaling results in tumor suppression, while chronic activation of cGAS-STING signaling results in immune-suppressive TME that could result in tumor survival. There is a need, therefore, to develop therapeutic strategies for harnessing tumor suppressive effects of cGAS-STING signaling while minimizing the risks associated with chronic activation. Combination therapies and nanocarriers-based delivery of cGAS-STING agonists have emerged as promising strategies in immunotherapy for controlled modulation of cGAS-STING signaling in cancer. These approaches aim to optimize the tumor suppressive effects of the cGAS-STING pathway while minimizing the challenges associated with modulators of cGAS-STING signaling. In the present review, we discuss recent advancements and strategies in combination therapies and nanocarrier-based delivery systems for effectively controlling cGAS-STING signaling in cancer immunotherapy. Further, we emphasized the significance of nanocarrier-based approaches for effective targeting of the cGAS-STING signaling, tackling resistance mechanisms, and overcoming key challenges like immune suppression, tumor heterogeneity, and off-target effects.

A new paradigm for cancer immunotherapy: targeting immunogenic cell death-related noncoding RNA

Cancer immunotherapy has shown significant potential in treating several malignancies by stimulating the host immune system to recognize and attack cancer cells. Immunogenic cell death (ICD) can amplify the antitumor immune responses and reverse the immunosuppressive tumor microenvironment, thus increasing the sensitivity of cancer immunotherapy. In recent years, noncoding RNAs (ncRNAs) have emerged as key regulatory factors in ICD and oncologic immunity. Accordingly, ICD-related ncRNAs hold promise as novel therapeutic targets for optimizing the efficacy of cancer immunotherapy. However, the immunomodulatory properties of ICD-related ncRNAs have not yet been comprehensively summarized. Hence, we summarize the current knowledge on ncRNAs involved in ICD and their potential roles in cancer immunotherapy in this review. It deepens our understanding of ncRNAs associated with ICD and provides a new strategy to enhance cancer immunotherapy by specifically targeting the ICD-related ncRNAs.

Two previously undescribed triterpenoid saponins from the roots and rhizomes of Caulophyllum robustum Maxim

Since ancient times, plants have provided humans with important bioactive compounds for the treatment of various diseases. Nine compounds were isolated from the roots and rhizomes of Caulophyllum robustum (a plant in the family Panaxaceae), including two new saponins C. Spanion A and C. Spanion B (1-2) and seven known saponins (3-9). The cytotoxicity of these compounds on human cancer cell lines was analyzed using MTT method. Compounds 6 and 9 exhibit cytotoxicity towards these three types of human cancer cells (<10 μM). By utilizing the SEA platform for target prediction, a common tumor related target CD81 was identified. The molecular docking of saponins 1, 2, 6, and 9 with CD81 protein showed strong binding affinities ranging from -4.5 to -7.1 kcal/mol. Research has shown that these compounds can become potential anti-tumor drugs. Further research is still recommended to understand its exact molecular mechanism and toxicological effects.

Raddeanin A Inhibits Colorectal Cancer Growth and Ameliorates Oxaliplatin Resistance Through the WNT/β-Catenin Signaling Pathway

Background: Chemotherapy based on oxaliplatin (OXA) is the first-line treatment for advanced colorectal cancer (CRC), and acquired resistance to OXA is the main reason for clinical treatment failure in CRC. Methods: To search for compounds that can reverse OXA resistance, we screened a small molecule inhibitor drug library and identified a drug, Raddeanin A (RA), that enhanced the anticancer effect of OXA. Using human CRC cell lines, CRC organoid models, and in vivo subcutaneous tumorigenic studies, we determined that RA inhibits the proliferation of CRC cells by promoting apoptosis and inducing cell cycle arrest. Results: We constructed OXA-resistant CRC cell lines and demonstrated that RA enhances the sensitivity of these cells to OXA. Further experiments showed that the mechanism by which RA enhanced the anticancer effects of OXA in CRC was by inhibiting the activation of the WNT/β-catenin signaling pathway. Conclusions: Because RA has been shown to be biocompatible in animal models, there is a possibility that RA could be developed as a sensitizer for resistant cancer cells or as a novel lead compound to enhance the therapeutic efficacy of OXA in resistant CRCs.

Chemical proteomics accelerates the target discovery of natural products

More than half of the global novel drugs are directly or indirectly derived from natural products (NPs) because of their better selectivity towards proteins. Traditional medicines perform multiple bioactivities through various NPs binding to drug targets, which highlights the opportunities of target discovery for drug development. However, detecting the binding relationship between NPs and targets remains challenging. Chemical proteomics, an interdisciplinary field of chemistry, proteomics, biology, and bioinformatics, has emerged as a potential approach for uncovering drug-target interactions. This review summarizes the principles and characteristics of the current widely applied chemical proteomic technologies, while delving into their latest applications in the target discovery of natural medicine. These endeavours demonstrate the potential of chemical proteomics for target discovery to supply dependable methodologies for the target elucidation of NPs.

Plant-derived natural compounds: A new frontier in inducing immunogenic cell death for cancer treatment

Immunogenic cell death (ICD) can activate adaptive immune response in the host with normal immune system. Some synthetic chemotherapeutic drugs and natural compounds have shown promising results in cancer treatment by triggering the release of damage-associated molecules (DAMPs) to trigger ICD. However, most chemotherapeutic drugs exhibit non-selective cytotoxicity and may also induce and promote metastasis, thereby significantly reducing their clinical efficacy. Among the natural compounds that can induce ICD, plant-derived compounds account for the largest proportion, which are of increasing value in the treatment of cancer. Understanding which plant-derived natural compounds can induce ICD and how they induce ICD is crucial for developing strategies to improve chemotherapy outcomes. In this review, we focus on the recent findings regarding plant-derived natural compounds that induce ICD according to the classification of flavonoids, alkaloids, glycosides, terpenoids and discuss the potential mechanisms including endoplasmic reticulum (ER) stress, DNA damage, apoptosis, necroptosis autophagy, ferroptosis. In addition, plant-derived natural compounds that can enhance the ICD induction ability of conventional therapies for cancer treatment is also elaborated. The rational use of plant-derived natural compounds to induce ICD is helpful for the development of new cancer treatment methods.

Gas-Amplified Metalloimmunotherapy with Dual Activation of Pyroptosis and the STING Pathway for Remodeling the Immunosuppressive Cervical Cancer Microenvironment

The immunosuppressive microenvironment of cervical cancer significantly hampers the effectiveness of immunotherapy. Herein, PEGylated manganese-doped calcium sulfide nanoparticles (MCSP) were developed to effectively enhance the antitumor immune response of the cervical cancer through gas-amplified metalloimmunotherapy with dual activation of pyroptosis and STING pathway. The bioactive MCSP exhibited the ability to rapidly release Ca2+, Mn2+, and H2S in response to the tumor microenvironment. H2S disrupted the calcium buffer system of cancer cells by interfering with the oxidative phosphorylation pathway, leading to calcium overload-triggered pyroptosis. On the other hand, H2S-mediated mitochondrial dysfunction further promoted the release of mitochondrial DNA (mtDNA), enhancing the activation effect of Mn2+ on the cGAS-STING signaling axis and thereby activating immunosuppressed dendritic cells. The released H2S acted as an important synergist between Mn2+ and Ca2+ by modulating dual signaling mechanisms to bridge innate and adaptive immune responses. The combination of MCSP NPs and PD-1 immunotherapy achieved synergistic antitumor effects and effectively inhibited tumor growth. This study reveals the potential collaboration between H2S gas therapy and metalloimmunotherapy and provides an idea for the design of nanoimmunomodulators for rational regulation of the immunosuppressive tumor microenvironment.

RECQL4 Inhibits Radiation-Induced Tumor Immune Awakening via Suppressing the cGAS-STING Pathway in Hepatocellular Carcinoma

Many patients with hepatocellular carcinoma (HCC) respond poorly to radiotherapy despite remarkable advances in treatment. A deeper insight into the mechanism of sensitivity of HCC to this therapy is urgently required. It is demonstrated that RECQL4 is upregulated in the malignant cells of patients with HCC. Elevated RECQL4 levels reduce the sensitivity of HCC to radiotherapy by repairing radiation-induced double-stranded DNA (dsDNA) fragments. Mechanistically, the inhibitory effect of RECQL4 on radiotherapy is due to the reduced recruitment of dendritic cells and CD8+ T cells in the tumor microenvironment (TME). RECQL4 disrupts the radiation-induced transformation of the TME into a tumoricidal niche by inhibiting the cGAS-STING pathway in dendritic cells. Knocking out STING in dendritic cells can block the impact of RECQL4 on HCC radiosensitivity. Notably, high RECQL4 expressions in HCC is significantly associated with poor prognosis in multiple independent cohorts. In conclusion, this study highlights how HCC-derived RECQL4 disrupts cGAS-STING pathway activation in dendritic cells through DNA repair, thus reducing the radiosensitivity of HCC. These findings provide new perspectives on the clinical treatment of HCC.

Sulfonated Perylene as Three-in-One STING Agonist for Cancer Chemo-Immunotherapy

Activation of stimulator of interferon genes (STING) by cyclic dinucleotides (CDNs) has been considered as a powerful immunotherapy strategy. While promising, the clinical translation of CDNs is still overwhelmed by its limited biostability and the resulting systemic immunotoxicity. Being differentiating from current application of exogenous CDNs to address these challenges, we herein developed one perylene STING agonist PDIC-NS, which not only promotes the production of endogenous CDNs but also inhibits its hydrolysis. More significantly, PDIC-NS can well reach lung-selective enrichment, and thus mitigates the systemic immunotoxicity upon intravenous administration. As a result, PDIC-NS had realized remarkable in vivo antitumor activity, and backward verified on STING knock out mice. Overall, this study states that PDIC-NS can function as three-in-one small-molecule STING agonist characterized by promoting the content and biostability of endogenous CDNs as well as possessing good tissue specificity, and hence presents an innovative strategy and platform for tumor chemo-immunotherapy.

Functional Materials for Subcellular Targeting Strategies in Cancer Therapy: Progress and Prospects

Neoadjuvant and adjuvant therapies have made significant progress in cancer treatment. However, tumor adjuvant therapy still faces challenges due to the intrinsic heterogeneity of cancer, genomic instability, and the formation of an immunosuppressive tumor microenvironment. Functional materials possess unique biological properties such as long circulation times, tumor-specific targeting, and immunomodulation. The combination of functional materials with natural substances and nanotechnology has led to the development of smart biomaterials with multiple functions, high biocompatibilities, and negligible immunogenicities, which can be used for precise cancer treatment. Recently, subcellular structure-targeting functional materials have received particular attention in various biomedical applications including the diagnosis, sensing, and imaging of tumors and drug delivery. Subcellular organelle-targeting materials can precisely accumulate therapeutic agents in organelles, considerably reduce the threshold dosages of therapeutic agents, and minimize drug-related side effects. This review provides a systematic and comprehensive overview of the research progress in subcellular organelle-targeted cancer therapy based on functional nanomaterials. Moreover, it explains the challenges and prospects of subcellular organelle-targeting functional materials in precision oncology. The review will serve as an excellent cutting-edge guide for researchers in the field of subcellular organelle-targeted cancer therapy.

Biomaterials Facilitating Dendritic Cell-Mediated Cancer Immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has exhibited remarkable clinical prospects because DCs play a central role in initiating and regulating adaptive immune responses. However, the application of traditional DC-mediated immunotherapy is limited due to insufficient antigen delivery, inadequate antigen presentation, and high levels of immunosuppression. To address these challenges, engineered biomaterials have been exploited to enhance DC-mediated immunotherapeutic effects. In this review, vital principal components that can enhance DC-mediated immunotherapeutic effects are first introduced. The parameters considered in the rational design of biomaterials, including targeting modifications, size, shape, surface, and mechanical properties, which can affect biomaterial optimization of DC functions, are further summarized. Moreover, recent applications of various engineered biomaterials in the field of DC-mediated immunotherapy are reviewed, including those serve as immune component delivery platforms, remodel the tumor microenvironment, and synergistically enhance the effects of other antitumor therapies. Overall, the present review comprehensively and systematically summarizes biomaterials related to the promotion of DC functions; and specifically focuses on the recent advances in biomaterial designs for DC activation to eradicate tumors. The challenges and opportunities of treatment strategies designed to amplify DCs via the application of biomaterials are discussed with the aim of inspiring the clinical translation of future DC-mediated cancer immunotherapies.

Raddeanin A Improves the Therapeutic Effect of Osimertinib in NSCLC by Accelerating ROS/NLRP3-mediated Pyroptosis

BACKGROUND

Osimertinib (Osm) is the preferred treatment for non-small cell lung cancer (NSCLC) patients with the epidermal growth factor receptor (EGFR) T790M mutation. Nevertheless, the resistance of NSCLC cells to Osm will eventually develop, which remains the biggest obstacle to treating such diseases. Raddeanin A (RA) exhibits a potent anti-tumor effect on various types of cancer cells. In this study, we aimed to investigate whether RA suppresses NSCLC growth and increases the therapeutic effect of Osm.

METHODS

The effects of RA on inhibiting NSCLC cell viability and proliferation were tested using cell counting kit 8 (CCK-8) and EdU assay. The roles of RA in improving the anti-tumor effect of Osm were tested with CCK-8 and colony formation assays. The roles of RA in regulating reactive oxygen species (ROS)/NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3)-mediated pyroptosis were assessed using quantitative real- time PCR (qRT-PCR) and western blotting analysis.

RESULTS

RA treatment decreased A549 and H1975 cell viability in a dose- and time-dependent way. RA inhibited NSCLC cell proliferation and tumor growth in vivo. Mechanistically, RA induced ROS overgeneration and resulted in subsequent NLRP3-mediated pyroptosis. In particular, combination treatment with Osm and RA reduced cell viability and clonogenic growth capacity more efficiently than Osm mono treatment in A549 and H1975 cells. Combination treatment also promoted NLRP3-mediated pyroptosis more efficiently than Osm mono treatment.

CONCLUSION

RA inhibited the NSCLC growth and increased the anti-tumor role of Osm in NSCLC by facilitating ROS/NLRP3-mediated pyroptosis. These results suggested that combination therapy with RA and Osm might be an effective strategy to treat Osm-resistant NSCLC.