ATM (ataxia-telangiectasia mutated) is a central regulator of the DNA damage response, coordinating double-strand break repair, checkpoint control, and cell fate decisions. Its disruption drives genomic instability and has been implicated across multiple tumour types. In oesophagogastric cancers, ATM alterations occur in a clinically relevant subset of cases, encompassing both somatic and germline events, and are associated with distinct molecular features including reduced co-occurrence with TP53 mutations and elevated homologous recombination deficiency scores. This narrative review synthesises published literature and publicly available genomic databases to examine ATM biology, the spectrum of ATM alterations across oesophageal adenocarcinoma, oesophageal squamous cell carcinoma, and gastric cancer subtypes, and the challenges of defining true ATM deficiency. The therapeutic implications of ATM dysfunction are evaluated across radiotherapy, platinum-based chemotherapy, ATR inhibition, and PARP inhibition. ATM alterations are detected in approximately 6% of tumours pan-cancer and in up to 10% of oesophagogastric cases. Defining ATM deficiency remains challenging, as immunohistochemistry, next-generation sequencing, and functional assays each carry distinct limitations. ATR inhibition emerges as the most consistently supported therapeutic strategy, with converging preclinical and early clinical evidence across oesophagogastric models. By contrast, available data do not support treating ATM deficiency as equivalent to BRCA-like homologous recombination deficiency, and PARP inhibitor monotherapy has not demonstrated consistent benefit. Prospective validation of functional ATM assays, histology-stratified trial design, and integration of genomic, protein-level, and functional evidence represent key priorities for translating ATM-guided strategies into oesophagogastric cancer practice.

In the original publication [...].

Flexible carriers that combine high drug loading and favorable drug compatibilities with a wider spectrum of more defined release properties are needed to broaden the scope of transdermal drug delivery systems (TDDS). Here, we transform rigid porous glass into flexible textile architectures by drawing SiO2-B2O3-Na2O fibers (50 and 150 & micro;m in diameter), inducing phase separation through controlled thermal treatment, and generating porosity via selective leaching. Differential scanning calorimetry revealed glass transition temperatures (T g) to be 40 degrees C-50 degrees C higher for fibers than for bulk glass, necessitating higher treatment temperatures in order to obtain comparable mesoporosity. After leaching, all materials exhibited similar to 20 nm pores. Woven textiles were fabricated using non-porous S2 warp threads and porous glass weft fibers, yielding 2 & times; 2 cm2 fabrics with preserved flexibility. Using anastrozole as a model drug, in vitro release experiments in a stirred container showed geometry-dependent drug release. Membranes delivered the payload within similar to 10 min. Alkaline-leached textiles displayed a similar burst profile but markedly higher loading capacities. Acid-leached textiles containing residual colloidal silica showed a gradual release over 24 h, reflecting increased tortuosity. Collectively, these results demonstrate that porous glass fiber textiles unite macroscopic flexibility with tunable pore architecture and drug transport, offering an inorganic platform that spans rapid to sustained release regimes and complements polymer-based TDDS.

RNA interference (RNAi) regulates gene expression through small RNAs that act via Argonaute-containing RNA-induced silencing complexes (RISCs). We previously found that short RNAs with G-rich 6mer seeds (e.g., GGGGGC and G5C) can kill cells by targeting C-rich 3 ' UTR seed matches in essential survival genes (SGs), a mechanism termed death induced by survival gene elimination (DISE). To assess therapeutic potential, we systemically delivered two DISE-inducing sRNAs, sG5C and sCAG (based on CAG trinucleotide repeats), using lipopolyplexes (LPPs) composed of low-molecular-weight polyethyleneimines and lipids. In mouse ovarian and prostate cancer models and a rat hepatocellular carcinoma model, LPP-delivered small RNAs (sRNAs) markedly reduced or eliminated tumors without harming normal tissues. Predicted SG targets were engaged in tumors. Transcriptomic analyses across 10 major human cancers showed that many sG5C-targeted SGs are consistently upregulated in tumors and increase with stage, revealing a therapeutic window. These results support LPP-delivered DISE-inducing sRNAs as a promising pan-cancer therapy.

Gastric cancer remains one of the most lethal malignancies worldwide, with high relapse rates and limited survival for patients with advanced disease. Despite advances in targeted therapies and immune checkpoint inhibition, intrinsic tumor heterogeneity poses challenges for effective treatment. The HER3 receptor (ERBB3) has emerged as an important player in cancer progression, contributing to aggressive tumor behavior and poor prognosis. Recent evidence indicates that activating ferroptosis—an iron-dependent, non-apoptotic form of cell death—offers a promising strategy to inhibit cancer growth. In gastric cancer, ferroptosis plays a crucial role, and promoting this process may open new avenues for therapeutic intervention. Ferroptosis is characterized by iron-mediated lipid peroxidation of cell membranes and is critically regulated by the cystine/glutamate antiporter system (SLC7A11) and glutathione peroxidase 4 (GPX4). Our study aimed to investigate the relationship between ERBB3 and ferroptosis in gastric cancer. We found that high ERBB3 expression correlated with resistance to ferroptosis-inducing agents, including GPX4 and SLC7A11 inhibitors, across multiple cell lines. Vice versa, ERBB3 inhibition with TX1-85-1 induced lipid peroxidation in gastric cancer cells, with effects most pronounced in cell lines expressing higher SLC7A11 levels. Knockdown of ERBB3 reproduced these effects, suggesting SLC7A11 as a predictive marker. Importantly, combined inhibition of ERBB3 and GPX4 significantly enhanced lipid peroxidation and cytotoxicity, while ERBB3 activation by co-treatment with the ERBB3 ligand heregulin reduced lipid peroxidation in cells with lower baseline SLC7A11 expression. Analysis of glutathione levels and SLC7A11 expression further supported the role of ERBB3 in modulating ferroptosis sensitivity. These findings identify ERBB3 as a critical regulator of ferroptosis and a promising target for enhancing ferroptosis-mediated cell death. Its inhibition in combination with ferroptosis inducers may thus represent a particularly promising and efficacious therapeutic strategy in gastric cancer.

RNA molecules offer attractive therapeutic strategies in oncology, based on mechanisms of action different to existing medications. The therapeutic application of RNAs, however, is still associated with major bottlenecks, including poor stability and pharmacokinetics. Non-viral nanoparticle formulations represent systems for RNA protection, delivery and cell internalization. They have to meet defined requirements for providing sufficient efficacy, specificity and biocompatibility. Moreover, the selection of the RNA drug as payload is of major relevance. As a result of intense research over the past decades, a wide variety of different RNA classes are available for interference with pathophysiological processes. This review provides an overview of various RNA classes as drug candidates, including RNAs mediating loss-of-function (siRNAs for gene knockdown, sgRNAs for gene knockout, gene- or base-editing), gain-of-function (mRNA, sa-mRNA, circRNA for ectopic overexpression) or modulation of gene expression (miRNAs, antimiRs or circRNAs for miRNA inhibition), among others. Dependent on the target organ, target cell and type of RNA molecule, different nanoparticle systems can provide efficient RNA formulations. New therapeutic strategies may also cover combinations of different types of RNAs, associated with different properties and thus requiring even more sophisticated nanocarriers for their delivery. The various classes of nanocarriers available for RNA formulation are reviewed and discussed as well. Beyond therapeutic in vivo application, RNA-based strategies may also be of relevance in cell-based therapies, for non-viral ex vivo modification of immune cells. While this would offer advantages over existing viral transduction strategies, it will also rely on sufficiently efficient non-viral systems for cell modification. Overall, nonviral systems for the delivery of RNA therapeutics are needed to fulfil the potential of these approaches in the clinic.

Background: Polymeric nanoparticles have been explored as efficient tools for siRNA delivery to induce RNAi-mediated gene knockdown. Chemical modifications of polyethylenimines (PEI) enhance nanoparticle efficacy and biocompatibility. Their in vivo use, however, benefits from prior analyses in relevant in vitro 3D conditions. Methods: We utilize a 3D ALI cell culture model for testing the biological activities and toxicities of a set of different PEI-based nanoparticles with different chemical modifications. This also includes a novel, fluoroalkyl-modified PEI. Reporter gene knockdown is directly compared to 2D cell culture. In parallel, biocompatibility is assessed by measuring cell viability and lactate dehydrogenase (LDH) release. Results: Knockdown efficacies in the 3D ALI model are dependent on the chemical modification and complex preparation conditions. Results only correlate in part with gene knockdown in 2D cell culture, identifying nanoparticle penetration and cellular internalization under 3D conditions as important parameters. The 3D ALI cell culture is also suitable for the quantitative determination of nanoparticle effects on cell viability and acute toxicity, with biocompatibility benefitting from PEI modifications. Conclusions: The 3D ALI cell model allows for a more realistic assessment of biological nanoparticle effects. A novel fluoroalkyl-modified PEI is described. Optimal preparations of PEI-based nanoparticles for siRNA delivery and gene knockdown are identified.

Introduction: Histone deacetylase inhibitors (HDACi) have shown promising preclinical activity in gastric cancer cells; unfortunately, however, these could not be confirmed in clinical trials. This highlights the need for the identification of underlying reasons, which may also provide the basis for possible combination therapies. Here, we delineated the effects of HDACi on components of EGFR signalling in gastric cancer cells. Methods: We investigated entinostat effects on EGFR and amphiregulin (AREG) expression in various cell line- and primary patient tumor-based in vitro, ex vivo and in vivo models, on the mRNA and protein level. Based on these results, a combined entinostat plus EGFR inhibitor erlotinib treatment in vitro and in vivo was studied. Results: Proteomics analyses in gastric cancer cells treated with entinostat revealed a marked upregulation of EGFR in the majority of cell lines and an even more robust induction of the EGFR ligand AREG. This was confirmed in a panel of different cell lines in vitro, in tumor tissue-slice cultures ex vivo and in cell line- or patient-derived tumor xenografts in mice. Since previous studies in other tumor entities showed a downregulation of EGFR by HDACi, our findings thus indicate essential differences in the adaptive response of gastric carcinoma cells. Moreover, our results provided the basis for combined entinostat + EGFR inhibitor (erlotinib) treatment, and indeed we demonstrate synergistic effects in combination therapy studies. Conclusion: Our findings establish the profound upregulation of the EGFR/AREG axis by entinostat as starting point for a rational combination therapy in gastric carcinoma.

Test systems enabling preclinical assessment of drug effects in relevant models are essential for optimizing the selection of candidate therapeutics before their further clinical translation. Xenograft tissue slice tandem co-culture (XTCC) models were developed as ex vivo systems for visualizing glioblastoma (GBM) tumor growth and invasion into the complex host tissue structures of the brain. Work here tested the XTCC model for delineating specific drug effects, in particular inhibition of invasion as major issue in GBM. The established chemotherapeutic Temozolomide (TMZ) and three promising candidates - two histone deacetylase inhibitors, Vorinostat and Entinostat, and the neuropeptide Apamin - were tested. XTCCs were generated by placing G55T2 or U87-MG cell-derived tumor xenograft tissue slices onto murine cortical brain slices. Upon drug treatment, effects on growth, invasion, proliferation, and apoptosis were analyzed by immunohistochemistry. Differences in invasion capacity were seen between the two cell lines. Profound invasion-inhibitory effects of 100 μM TMZ were accurately monitored and substantially higher than inhibition of the bulk tumor mass. Likewise, the extent of single-cell invasion into the normal brain tissue was massively inhibited by Vorinostat and especially by Entinostat, indicating that histone deacetylase inhibitor treatment is particularly efficient in inhibiting GBM cell invasion. Despite the absence of inhibitory effects of Apamin in 2D cell culture, G55T2 XTCCs revealed ∼70% reduced GBM invasion, associated with a substantial inhibition of proliferation as indicated by loss of Ki-67 positivity. Taken together, we show the suitability of the XTCC models for monitoring tumor growth and, in particular anti-invasive effects of drugs.

PURPOSE:Human epidermal growth factor receptor 2 (HER2) inhibition represents a therapeutic approach with proven clinical efficacy in gastric cancer. However, resistance against HER2-directed therapeutics highlights the need for alternative approaches or drug combinations. Histone deacetylase inhibitors (HDACi) display a broad spectrum of antitumor properties, which may include effects on receptor tyrosine kinases. Materials and Methods:We analyzed the effects of the class I HDACi entinostat in a panel of HER2-amplified and non-amplified gastric adenocarcinoma cells in 2D cell culture as well as in tumor slice models ex vivo and in patient-derived xenografts in vivo. Effects on protein expression/signal transduction were evaluated by immunoblotting and quantitative reverse transcription polymerase chain reaction. RESULTS:HDAC inhibition reduced HER2 protein expression independently of initial HER2 expression levels. This was associated with the upregulation of the HER2-inhibiting microRNA miR-205. The downregulation of HER2 resulted in reduced AKT phosphorylation, apoptosis induction and antiproliferative effects, with particularly high efficiency in HER2-amplified gastric cancer cells. Inhibiting HER2 by a specific kinase inhibitor in gastric cancer cells with low basal HER2 expression led to HER2 upregulation. This was reversed by entinostat treatment and provided the basis for synergistic cell inhibition upon double treatment. CONCLUSION:We describe the downregulation of HER2 in gastric carcinoma cells upon HDACi treatment. Concomitantly, cells with high basal or treatment-induced HER2 expression showed most profound sensitivities towards HDACi. These findings may thus provide the basis for HDACi treatment as a therapeutic option particularly valuable in HER2-amplified gastric cancer and particularly useful in combination therapies with HER2 inhibitors.

Myocardin-related transcription factor A (MRTF-A) is a coactivator of the transcription factor serum response factor (SRF) that promotes the expression of genes involved in cell proliferation, migration and differentiation and triggers HCC progression. Therapeutic knockdown of MRTF-A induces senescence and quiescence in HCC xenografts and may be harnessed as a novel molecularly targeted strategy for the treatment of HCCs and recurrent disease. We recently demonstrated that the negative gating modulator NS8593 of the transient receptor potential cation channel TRPM7 inhibits MRTF-A by promoting its nuclear export. We generated derivatives of NS8593, which are more potent in inhibiting SRF transcriptional activity, as determined by reporter gene assays. Remarkably, we assessed MRTF-A nuclear localization by Fluorescence Loss in Photobleaching (FLIP) to define responsiveness to the novel MRTF inhibitors. Upon administration of the improved NS8593 analogs, nuclear export of MRTF-A was increased and the expression of the MRTF/SRF target genes such as transforming growth factor β1 (TGF-β1) and tetraspanin 5 (TSPAN5) was significantly reduced, resulting in senescence induction and proliferation arrest in HCC cells. Our novel MRTF inhibitors highlight the therapeutic potential of targeting this pathway, also in combination therapies with receptor tyrosine kinase inhibitors. Thus, our studies illuminate for the first time the potential of combining MRTF-A inhibitors with established therapies to combat HCC growth and drug resistance. Miriam Jasmin Franz, Laura Rupprecht, Pia Wenisch, Petra Wohlleben, Vladimir Chubanov, Thomas Gudermann, Salla Kyheröinen, Achim Aigner, Maria Kristina Vartiainen, Markus Heinrich, Susanne Mühlich. Deciphering novel MRTF-A inhibitors and combination strategies for HCC therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB232.

Prostate cancer that is resistant to anti-androgen treatment, such as enzalutamide, represents a therapeutic challenge. To study their molecular and functional features, the enzalutamide-resistant PCa cell lines LNCaP Abl EnzR and DuCaP EnzR constitute valuable in vitro models. In this work, we explored two different strategies for reducing AR/AR-V7/c-Myc. MED12 knockdown decreased the protein expression of AR, AR-V7 and c-Myc. Similarly, we identified AR and AR-V7 as targets of miR-454-3p. Concomitantly, the transfection of synthetic miR-454-3p reduced the protein expression of AR in both EnzR cell lines and that of c-Myc and AR-V7 in the DuCaP EnzR cell line without affecting MED12. Despite these similar molecular effects, differences were observed at the cellular level, with siMED12, but not miR-454, reducing cell viability, and no additive effects upon double treatment were observed. Taken together, the results of our study suggest MED12 as a potential target for future PCa treatment in conjunction with enzalutamide resistance. Furthermore, miR-454-3p, which directly targets AR and AR-V7 and indirectly influences c-Myc protein expression, reveals new molecular mechanisms in PCa biology.

Potential strategies to develop new treatments for Parkinson’s disease (PD) aim at targeting disease-associated proteins like alpha-synuclein (aSyn), which accumulates in neurons of PD patients and contributes to neuronal degeneration. A promising new approach is the therapeutic use of small interfering RNAs (siRNAs) for aSyn knockdown, but is challenging due to siRNA instability, poor delivery, and inefficient uptake. Therefore, we developed a nanoparticle-based approach for intranasal delivery of siRNAs, circumventing the blood-brain barrier and enhancing the potential of siRNAs for clinical application. Tyrosine-modified polyethylenimines (PEIs), or polypropylenimine dendrimers (PPIs), were complexed with siRNA targeting the aSyn-encoding gene SNCA (siSNCA) and combined with liposomes. Nanoparticles efficiently transfected SH-SY5Y cells with low cytotoxicity and significantly reduced SNCA mRNA levels. In Thy1-aSyn mice, intranasally administered labeled nanoparticles distributed extensively across the brain, including the olfactory bulb, substantia nigra, and prefrontal cortex. After only 4 days of treatment, siSNCA-loaded nanoparticles significantly reduced aSyn protein and SNCA mRNA levels in the brain. Mice showed neither overt adverse behavioral effects nor increased reactive microglia. These findings highlight the potential of nanoparticle-mediated intranasal siRNA delivery as a promising, non-invasive approach to reduce aSyn levels in the brain, offering a novel therapeutic strategy for Parkinson’s disease.

Transdermal Drug Delivery Systems (TDDS) show significant advantages over other forms of drug application. Despite their clinical use for decades, these drug delivery devices have yet to reach their full potential. While polymer matrices are most commonly used as transdermal patches so far, inorganic carriers like mesoporous silica membranes offer several advantages, including chemical stability and their tunable porous system, with adjustable pore sizes, pore volumes and surface chemistries. In this study, we chemically modified high and low porosity mesoporous silica membranes by post-synthetic methods and compared the effects of different surface modifications on loading efficacies and release profiles of different pharmacologically relevant drugs with different chemical properties. Drug loading capacities and release profiles were substantially affected by pore structure and surface modifcations with strongly acidic SO3H groups or hydrophobic methyl groups, while weakly acidic COOH groups or nitrile groups showed little effects. SO3H modification of low porosity (LP) membranes led to markedly increased loading capacity and a more sustained release profile of anastrozole. The latter was also observed for xylazine, but associated with lesser drug loading. Likewise, the SO3H modification also slowed down the release of imiquimod or flunixin. Increasing LP membrane hydrophobicity by methyl modification essentially abolished anastrozole drug loading. In high porosity (HP) membranes, effects of chemical surface modifications were overall weaker. This led to particularly slow anastrozole or xylazine release profiles from methyl-modified membranes. Biocompatibility studies showed some cell-inhibitory effects of CN functionalization, but full biocompatibility of SO3H functionalized membranes as indicated by efficient cell attachment and high viability. Both parameters, pore structure and chemical surface modifcations, drug-dependently affect drug loading and release properties. Since they can be precisely fine-tuned in mesoporous silica membranes, this allows for the development of optimized TDDS providing high drug loading and the desired release profile of a given drug. Our results presented here indicate that the SO3H modification is particularly useful in this regard.

Hypoxia and low glucose abundance often occur simultaneously at sites of inflammation. In monocytes and macrophages, glucose-oxygen deprivation stimulates the assembly of the NLRP3 inflammasome to generate the proinflammatory cytokine IL-1β. We found that concomitant glucose deprivation and hypoxia activated the NLRP3 inflammasome by constraining the function of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate kinase pathway. HMGCR is involved in the synthesis of geranylgeranyl pyrophosphate (GGPP), which is required for the prenylation and lipid membrane integration of proteins. Under glucose-oxygen deprivation, GGPP synthesis was decreased, leading to reduced prenylation of the small GTPase Rac1, increased binding of nonprenylated Rac1 to the scaffolding protein IQGAP1, and enhanced activation of the NLRP3 inflammasome. In response to restricted oxygen and glucose supply, patient monocytes with a compromised mevalonate pathway due to mevalonate kinase deficiency or Muckle-Wells syndrome released more IL-1β than did control monocytes. Thus, reduced GGPP synthesis due to inhibition of HMGCR under glucose-oxygen deprivation results in proinflammatory innate responses, which are normally kept in check by the prenylation of Rac1. We suggest that this mechanism is also active in inflammatory autoimmune conditions.

Prostate cancer progression is driven by androgen receptor (AR) activity, which is a target for therapeutic approaches. Enzalutamide is an AR inhibitor that prolongs the survival of patients with advanced prostate cancer. However, resistance mechanisms arise and impair its efficacy. One of these mechanisms is the expression of AR-V7, a constitutively active AR splice variant. The Mediator complex is a multisubunit protein that modulates gene expression on a genome-wide scale. MED12 and cyclin-dependent kinase (CDK)8, or its paralog CDK19, are components of the kinase module that regulates the proliferation of prostate cancer cells. In this study, we investigated how MED12 and CDK8/19 influence cancer-driven processes in prostate cancer cell lines, focusing on AR activity and the enzalutamide response. We inhibited MED12 expression and CDK8/19 activity in LNCaP (AR+, enzalutamide-sensitive), 22Rv1 (AR-V7+, enzalutamide-resistant), and PC3 (AR-, enzalutamide-insensitive) cells. Both MED12 and CDK8/19 inhibition reduced cell proliferation in all cell lines, and MED12 inhibition reduced proliferation in the respective 3D spheroids. MED12 knockdown significantly inhibited c-Myc protein expression and signaling pathways. In 22Rv1 cells, it consistently inhibited the AR response, prostate-specific antigen (PSA) secretion, AR target genes, and AR-V7 expression. Combined with enzalutamide, MED12 inhibition additively decreased the AR activity in both LNCaP and 22Rv1 cells. CDK8/19 inhibition significantly decreased PSA secretion in LNCaP and 22Rv1 cells and, when combined with enzalutamide, additively reduced proliferation in 22Rv1 cells. Our study revealed that MED12 and CDK8/19 regulate AR activity and that their inhibition may modulate response to enzalutamide in prostate cancer.

Spray-drying of nucleic acid-based drugs designed for gene therapy or gene knockdown is associated with many advantages including storage stability and handling as well as the possibility of pulmonary application. The encapsulation of nucleic acids in nanoparticles prior to spray-drying is one strategy for obtaining efficient formulations. This, however, strongly relies on the definition of optimal nanoparticles, excipients and spray-drying conditions. Among polymeric nanoparticles, polyethylenimine (PEI)-based complexes with or without chemical modifications have been described previously as very efficient for gene or oligonucleotide delivery. The tyrosinemodification of linear or branched low molecular weight PEIs, or of polypropylenimine (PPI) dendrimers, has led to high complex stability, improved cell uptake and transfection efficacy as well as high biocompatibility. In this study, we identify optimal spray-drying conditions for PEI-based nanoparticles containing large plasmid DNA or small siRNAs, and further explore the spray-drying of nanoparticles containing chemically modified polymers. Poly(vinyl alcohol) (PVA), but not trehalose or lactose, is particularly well-suited as excipient, retaining or even enhancing transfection efficacies compared to fresh complexes. A big mesh size is critically important as well, while the variation of the spray-drying temperature plays a minor role. Upon spray-drying, microparticles in a similar to 3.3- 8.5 mu m size range (laser granulometry) are obtained, dependent on the polymers. Upon their release from the spray-dried material, the nanoparticles show increased sizes and markedly altered zeta potentials as compared to their fresh counterparts. This may contribute to their high efficacy that is seen also after prolonged storage of the spray-dried material. We conclude that these spray-dried systems offer a great potential for the preparation of nucleic acid drug storage forms with facile reconstitution, as well as for their direct pulmonary application as dry powder.