Endoplasmic reticulum stress (ER-stress) is recognized to have a major role in both the onset and progression of various diseases, including cancer. Therefore, much research has focused on developing chemical chaperones or small compounds to reduce ER-stress in various disease conditions.

Zinc Finger and BTB Domain-containing7A (ZBTB7A) is a member of the transcription factor family that regulates the expression of numerous genes involved in cell proliferation and differentiation. Ubiquitously expressed in colon, stomach, and other tissues, ZBTB7A performs diverse functions including hematopoiesis, metabolism, and oncogenesis. Here we showed that ZBTB7A knockout inhibited the growth of colon cancer cells and reduced CD95 protein expression by decreasing CD95 mRNA transcription. Overexpression of ZBTB7A could partially restore both CD95 expression and CD95-mediated downstream Caspase2 and JNK2 expression. Furthermore, treatment with ZBTB7A specific inhibitor Curcumin effectively induced colorectal cancer cell death while reducing CD95 expression. These data indicate that ZBTB7A promotes colon cancer cell growth and survival, suggesting its potential as a therapeutic target for colorectal cancer.

Doxorubicin (DOX) is an anthracycline derivative, a conversant chemotherapeutic agent, and one of the most influential chemotherapeutic drugs. Long noncoding RNAs (lncRNAs) play a vital role in this process. The current review demonstrates that lncRNAs can function as oncogenic and tumor suppressors and contribute to cancer development and progression. Our study addressed the nuclear-enriched abundant transcript 1 (NEAT1) and the effect of DOX on the regulation of miR410-3p by NEAT1.

A global priority for ameliorating male factor infertility includes identification of environmental factors and mechanisms that impact sperm function. Detection of endocrine disrupting chemicals (EDC) in seminal plasma and within the female reproductive tract has created an urgent need to understand how environmental stressors alter postejaculatory sperm function. Tributyltin chloride (TBT) is an EDC and epigenetic modifier that causes reproductive disorders. The consequences of TBT exposure on postejaculatory sperm remain unknown. The present study was aimed at identifying structural, genomic, and epigenomic consequences of TBT exposure to postejaculatory sperm. Bovine sperm were exposed to TBT (0, 1, 10, 100 nM) for 24 h followed by quantification of sperm kinematics, DNA integrity, and methylation status. No differences were detected in sperm kinematics or capacitation status. However, acrosome integrity was compromised at both 0 and 24 h (P ≤ 0.05). Sperm DNA integrity was also negatively affected after 24 h. Whole-genome methyl-seq revealed ~750 differentially methylated regions (DMRs) associated with exposure to TBT. Ingenuity Pathway Analyses and Gene Ontology identified embryo development, cell signaling, and transcriptional regulation as the most relevant bio-functions of TBT altered DMRs. In conclusion, postejaculatory mammalian sperm exposure to TBT negatively affected parameters important for sperm function while altering DNA integrity and the methylation profile of gene promoter regions. Consequences of sperm exposure to TBT included cellular and molecular mechanisms that are important for sperm function but remain undetected by routine clinical analyses. These findings provide new insight into environmental impacts on postejaculatory sperm structure and function.

Metabolic (dysfunction)-associated steatotic liver disease (MASLD), the hepatic consequence of metabolic syndrome, affects 30% of the global population. Studies in animals and humans investigating the effect of fructose on MASLD present conflicting findings, while in vitro methods often fail to add meaningful evidence due to acute exposures (<72 h) and non-physiological concentrations. This study aimed to determine the effect of fructose on triglyceride (TG) accumulation in HepG2 cells following acute and chronic exposures and assess its effect on the expression of genes related to de novo lipogenesis (DNL).

Osteoblastogenesis plays a critical role in bone repair. Insulin and insulin-mimetic compounds, such as vanadium (IV) oxide acetylacetonate (VAC), have been reported to enhance bone healing in various models. This study aimed to evaluate the effects of vanadium compounds, VAC and vanadium (IV) oxide sulfate (VOSO4), on osteoblast proliferation and function. MC3T3-E1 pre-osteoblast cells were treated with insulin, ascorbic acid, and varying concentrations of VAC or VOSO4, and samples were collected at multiple time points over 21 days. We assessed cell proliferation, functional markers, and gene and protein expression. Our findings demonstrate that both VAC and VOSO4 stimulate MC3T3-E1 proliferation, increase calcium and proteoglycan deposition, and enhance phosphorylation of Protein Kinase B (Akt) over time. Gene expression analysis revealed that VAC treatment upregulated RUNX2, BGLAP, and TWIST2 at Day 7 compared to controls, with sustained expression patterns observed at Day 10. These results align with existing literature, supporting that VAC and VOSO4 promote osteoblastogenesis and may serve as effective adjuvants to accelerate bone regeneration during fracture healing.

Neuroblastoma (NB) is an aggressive pediatric cancer, with high-risk patients facing a five-year survival rate of ~50%. Standard therapies, including surgery, chemotherapy, radiation, and immunotherapy, are associated with significant long-term toxicities and frequent relapse. Histone deacetylase (HDAC) inhibitors have emerged as promising agents for cancer therapy, given their role in modulating gene expression and tumor phenotypes. This study evaluated M344 [4-(dimethylamino)-N-(7-(hydroxyamino)-7-oxoheptyl)benzamide], an HDAC inhibitor, for its efficacy and mechanisms of action against NB. Analysis of clinical NB Gene Expression Omnibus data revealed advanced-stage tumors exhibit higher HDAC expression relative to early-stage samples. M344 treatment effectively increased histone acetylation, induced G0/G1 cell cycle arrest, and activated caspase-mediated cell death. Relative to vorinostat, an HDAC inhibitor in clinical use for lymphoma and clinical trials for NB, M344 displayed superior cytostatic, cytotoxic, and migration-inhibitory effects. In vivo, metronomic M344 dosing suppressed tumor growth and extended survival. Combination therapy with M344 and topotecan improved topotecan tolerability, while M344 co-administration with cyclophosphamide reduced tumor rebound post-therapy. In total, M344 demonstrated strong therapeutic potential for NB, offering improved tumor suppression, reduced off-target toxicities, and enhanced control of tumor growth post-therapy. These findings support further investigation of HDAC inhibitors, such as M344, for clinical application in NB treatment.

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal malignancies due to late diagnosis, poor drug penetration, and intrinsic chemoresistance. Targeted delivery strategies are urgently needed to enhance therapeutic precision while minimizing systemic toxicity. Here, we developed an AS1411 aptamer-functionalized liposomal platform encapsulating siRNA against metastasis-associated protein 2 (MTA2), a chromatin remodeling factor that suppresses the tumor suppressor PTEN and activates PI3K/AKT signaling. The AS1411 aptamer, which binds nucleolin overexpressed on PDAC cells, was conjugated to cationic liposomes via copper-free click chemistry. The resulting AS1411-Lipm[siRNA] exhibited high siRNA encapsulation efficiency, selective uptake by nucleolin-positive PDAC cells, and enhanced endosomal escape. Treatment of MIA PaCa-2 cells with AS1411-Lipm[siRNA] significantly reduced MTA2 expression by ~60%, substantially restored PTEN, and inhibited AKT phosphorylation by ~50%, leading to decreased cell viability, impaired migration by ~75%, and increased apoptosis by ~35%, while sparing nucleolin-negative cells. These findings highlight AS1411-Lipm[siRNA] as a promising platform for selective siRNA delivery and potent molecular inhibition in PDAC therapy.

B-box (BBX) transcription factors, which are specific to the plant kingdom, play a crucial role in regulating light-dependent growth, development, secondary metabolite biosynthesis, and the response to biotic and abiotic stresses. Despite their significance, there has been a lack of systematic investigation into the BBX gene family in Ginkgo biloba. In the present study, we identified nine BBX genes within the G. biloba reference genome, distributed across seven chromosomes, and classified them into four groups based on their phylogenetic relationships with the BBX gene families of Arabidopsis thaliana. Our analysis of gene structure, conserved domains, and motifs suggests that GbBBXs exhibit a high degree of conservation throughout evolutionary history. Additionally, synteny analysis revealed that dispersed duplication events have contributed to the expansion of the BBX gene family in G. biloba. An examination of cis-regulatory elements indicated that numerous GbBBX genes contain motifs associated with light, hormones, and stress, suggesting their potential roles in responding to these signals and environmental adaptation. Expression profiles obtained from RNA-Seq data and quantitative Real-Time PCR (qRT-PCR) analyses of GbBBX genes across various organs, hormone treatments, and leaves with differing flavonoid content, as well as during both short-term and long-term water stress, demonstrated their potential roles in flavonoid regulation and responses to hormones and water stress. Subcellular localization studies indicated that the proteins GbBBX5, GbBBX7, GbBBX8, and GbBBX9 are localized within the nucleus. This study is the first thorough analysis of the BBX gene family in G. biloba, providing a valuable foundation for further understanding their evolutionary context and functional roles in flavonoid regulation and responses to water stress.

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, often diagnosed at an advanced stage due to its asymptomatic progression. The high recurrence rate and development of platinum-based chemotherapy resistance contribute to its poor prognosis. Despite advancements in molecular profiling, predictive biomarkers for chemotherapy response and recurrence risk remain limited. In this study, we developed OvarianTag™, a biomarker panel integrating apoptosis and necroptosis pathways, to predict chemotherapy benefit and disease progression in EOC patients. This observational study was conducted in two phases. In the first phase, 45 patients were recruited, and RNA was extracted from fresh ovarian tissues (normal, benign, and malignant). qRT-PCR was performed to assess the relative expression of genes involved in apoptosis and necroptosis-regulated cell death pathways. Machine learning algorithms were applied to identify the relevant prognostic markers, leading to the development of OvarianTag™. In the second phase, 55 additional EOC patients were included, and their formalin-fixed, paraffin-embedded (FFPE) tumor samples were analyzed using qRT-PCR. The classifier algorithm incorporated hierarchical clustering to stratify patients based on gene expression profiles. Significant differences in TNFRSF10C/TRAIL-R3, TNFRSF10B/TRAIL-R2, and CASP8 expression levels were observed between patient groups. CASP8 downregulation was strongly correlated with platinum resistance and a poor prognosis. Decision tree models achieved 83.3% accuracy in predicting platinum response and 79.2% accuracy in recurrence risk stratification. The OvarianTag™ classifier demonstrated high sensitivity and specificity in identifying high-risk patients, supporting its potential as a prognostic tool. The OvarianTag™ panel provides a novel approach for risk stratification in EOC, integrating apoptosis and necroptosis pathways to refine chemotherapy response prediction and recurrence risk assessment. This molecular assay has the potential to guide personalized treatment strategies, enhancing clinical decision-making and improving patient outcomes. Further validation in independent cohorts is warranted to establish its clinical utility.

Singlet oxygen (1O2), a reactive oxygen species, can oxidize lipids, proteins, and DNA at high concentrations, leading to cell death. Despite its extremely short half-life (10-5 s), 1O2 acts as a critical signaling molecule, triggering a retrograde pathway from chloroplasts to the nucleus to regulate nuclear gene expression. In this study, rice seeds were treated with 0, 5, 20 and 80 μM Rose Bengal (RB, a photosensitizer) under moderate light for 3 days to induce 1O2 generation. Treatment with 20 μM RB reduced stomatal density by approximately 25% in three-leaf-stage rice seedlings, while increasing the contents of pectin, hemicellulose, and cellulose in root cell walls by 30-40%. Under drought, salinity, or shading stress, 20 μM RB treatment significantly improved rice tolerance, as evidenced by higher relative water contents (49-58%) and chlorophyll contents (60-76%) and lower malondialdehyde (37-43%) and electrolyte leakage (29-37%) compared to the control. Moreover, RT-qPCR analysis revealed that the significant up-regulation of stomatal development genes (OsTMM and OsβCA1) and cell wall biosynthesis genes (OsF8H and OsLRX2) was associated with RB-induced 1O2 production. Thus, under controlled environmental conditions, 1O2 may regulate stomatal development and cell wall remodeling to enhance rice tolerance to multiple abiotic stresses. These results provide new perspectives for the improvement of rice stress tolerance.

The glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) are ligand-activated transcription factors that regulate epidermal homeostasis, inflammation, and function. Prior studies using epidermal-specific conditional single and double knockout mice have shown their importance in skin physiology; however, clinically human disease is largely treated pharmacologically. Our objective was to examine how systemic MR/GR antagonism affects cutaneous gene expression and epidermal thickness in aged (18-month-old) C57BL/6J female mice. Mice were treated with selective GR (relacorilant), selective MR (eplerenone), or dual GR/MR (miricorilant) antagonists for 8 weeks. Quantitative RT-qPCR analysis of the skin showed that miricorilant significantly upregulated Sgk1, a GR/MR target. Miricorilant also increased the expression of keratinocyte differentiation markers and downregulated key inflammatory cytokines and Col3a1, a collagen subtype associated with tissue remodeling. Relacorilant suppressed Scnn1g, a subunit of the epithelial sodium channel. None of the antagonists significantly altered proliferation markers, epidermal thickness, or regulators of glucocorticoid activity. Our findings show that miricorilant downregulated inflammatory cytokines and increased differentiation marker expression without affecting epidermal thickness, suggesting its potential to treat inflammatory skin diseases. The results contrast with data from GR/MR knockout studies, highlighting the likely significance of receptor dynamics. Further studies of antagonist effects on receptor interactions with co-regulators appear warranted.

Grapevine (Vitis vinifera) is highly susceptible to fungal diseases, particularly downy mildew caused by Plasmopara viticola. Environmental contamination and potential health risks to viticulturists have raised concerns about the long-term sustainability of chemical control. In this study, we evaluated the potential of four biosurfactants-surfactin, rhamnolipid, sophorolipid, and spiculisporic acid-as alternative agents to chemical fungicides for disease management in viticulture. Surfactin, rhamnolipid, and sophorolipid, but not spiculisporic acid, significantly reduced the severity of grape downy mildew and strawberry anthracnose and induced the expression of defense-related genes, such as β-1,3-glucanase and class IV chitinase, in grapevine and strawberry leaves, although each biosurfactant triggered distinct gene expression patterns. Utilizing salicylic acid (SA)- and jasmonate (JA)-insensitive mutants of Arabidopsis thaliana, we found that sophorolipid induced plant resistance through the canonical SA signaling pathway. In contrast, plant resistance induced by surfactin and rhamnolipid was independent of both the SA and JA signaling pathways. Notably, sophorolipid was the only biosurfactant that induced systemic acquired resistance in grapevine leaves through unknown signaling pathways, suppressing P. viticola infection at sites distant from the treatment area. These findings suggest that biosurfactants, particularly sophorolipids, are a promising eco-friendly alternative to conventional fungicides in viticulture.

Cancer is one of the leading causes of human mortality worldwide, and aberrant expression of the c-myb oncogene is closely associated with the development of numerous malignancies. The c-myb promoter region contains G-rich and C-rich sequences capable of forming G-quadruplex (G4) and i-motif (IM or C-quadruplex) structures, respectively. These secondary structures function as "molecular switches" for gene transcriptional regulation and represent promising targets for novel anti-tumor therapeutics. Through extensive screening, we identified carbazole derivative G51 as a unique dual-targeting ligand that simultaneously destabilized the i-motif and stabilized the G-quadruplex, consequently suppressing c-myb expression efficiently. In comparison, the single-targeting ligand G50, which could specifically bind to and unfold the G-quadruplex only, exhibited significantly weaker anti-tumor activity than G51. Notably, G51 showed potent anti-tumor efficacy in a human colorectal cancer xenograft model without significant toxicity to vital organs. G51, as a dual-targeting ligand, had specific binding to c-myb promoter quadruplexes, with destabilization of the i-motif and concurrent stabilization of the G-quadruplex. This opposing effect could provide a good opportunity for specific gene regulation, with great potential for further development of a precise therapeutic agent. This study provides a novel example for a practical therapeutic approach through coordinated gene quadruplex modulations, which sets up a good foundation for developing high-efficacy anti-tumor drugs without significant side effects.

α-Cyclodextrin/Moringin (α-CD/MOR) is an isothiocyanate showing neuroprotective and antioxidant properties. In this work, we studied in differentiated NSC-34 motor neurons cell line the molecular pathways activated following a treatment of 96 h with α-CD/MOR at different doses, namely 0.5, 5 and 10 μM. Taking advantage of comparative transcriptomic analysis, we retrieved the differentially expressed genes (DEGs) and we mapped DEGs to synaptic genes using the SynGO database. Then, we focused on the biological pathways in which they are involved. We observed that the prolonged treatment with α-CD/MOR significantly modulated biological processes and cellular components associated with synaptic organization. Interestingly, the KEGG pathway "Regulation of actin cytoskeleton" was overrepresented, alongside pathways related to synapses and axon guidance. Specifically, SPIA analysis indicated that the "Regulation of actin cytoskeleton" pathway was found to be activated with the highest dose of α-CD/MOR. Moreover, α-CD/MOR also modulated transcription factors involved in synaptic plasticity, such as Creb1. These results could indicate that α-CD/MOR can influence synaptic functions and organization, being involved in synaptic plasticity through the modulation of actin dynamics.

Doxorubicin (DOX) is an anthracycline chemotherapeutic agent that is clinically limited by doxorubicin-induced cardiotoxicity (DIC), with ferroptosis and apoptosis identified as key mechanisms. As an antioxidant enzyme, GPX4 undergoes ubiquitin-mediated degradation during myocardial ischemia-reperfusion injury; however, the role of its ubiquitination in DIC remains unclear. This study revealed that GPX4 undergoes ubiquitinated degradation during DIC, exacerbating ferroptosis and apoptosis in cardiomyocytes. NEDD4L was found to interact with GPX4, and its expression was upregulated in DOX-treated mouse myocardial tissues and cardiomyocytes. NEDD4L knockdown alleviated DIC, as well as ferroptosis and apoptosis in cardiomyocytes. Mechanistically, NEDD4L recognizes GPX4 through its WW domain and mediates K48-linked ubiquitination and degradation of GPX4 under DOX stimulation via its HECT domain. Knockdown of NEDD4L reduced DOX-induced GPX4 ubiquitination levels and subsequent degradation. Notably, while NEDD4L knockdown mitigated DOX-induced cell death, concurrent GPX4 knockdown attenuated this protective effect, indicating that GPX4 is a key downstream target of NEDD4L in regulating cardiomyocyte death. These findings identify NEDD4L as a potential therapeutic target for preventing and treating DIC.

Sulforaphane (SFN) is a bioactive compound belonging to the isothiocyanate family, known for its neuroprotective properties. While transcriptomic studies have highlighted SFN's role in regulating gene expression, its impact on alternative splicing (AS), a key regulatory mechanism in neuronal metabolism, remains underexplored. In this study, we investigated whether SFN pre-treatment influences mRNA splicing patterns in an in vitro neuronal model using retinoic acid (RA)-differentiated SH-SY5Y cells. Using a dedicated RNA-seq-based splicing analysis pipeline, we identified 194 differential alternative splicing events (DASEs) associated with SFN treatment. Gene Ontology enrichment revealed significant over-representation of DNA repair processes. To better understand the functional implications, we integrated in silico predictions of premature stop codons, DASE/miRNA hybridizations, and DASE/RNA-binding protein (RBP) motif occurrences. Our findings suggest that SFN may modulate splicing of key DNA repair genes, contributing to protecting neurons against DNA damage. These preliminary results underscore a novel layer of SFN's molecular effects and propose it as a valuable adjuvant in physiological conditions to enhance cellular health. Further studies are warranted to dissect the mechanistic underpinnings of SFN-mediated AS and its relevance in DNA-damage-related disorders.

Copper ions serve as essential cofactors for many enzymes but exhibit toxicity at elevated concentrations. In Gram-negative bacteria, the Cop system, typically encoded by copABCD, plays a crucial role in maintaining copper homeostasis and detoxification. The chromosome of Pseudomonas putida harbors two copAB clusters but lacks copCD, along with two copR-copS clusters that encode the cognate two-component system. Here, the roles of these Cop components in countering copper toxicity were studied. We found that copAB2 was essential for full resistance to Cu2+ in P. putida, while copAB1 made only a minor contribution, partially due to its low expression. The two-component systems CopRS1 and CopRS2 both played significant regulatory roles in copper resistance. Although they could compensate for the absence of each other to mediate copper resistance, they exhibited distinct regulatory effects. CopR1 bound to all four cop promoters and activated their transcription under copper stress. In contrast, though CopR2 bound to the same sites as CopR1 in each cop promoter, it significantly activated only copAB2 and copRS2 expression. Its competitive binding at the copAB1 and copRS1 promoters likely impeded CopR1-mediated activation of these genes. Overall, this study reveals the distinct contributions of the two Cop systems to copper resistance and their regulatory interplay in P. putida.

This study aimed to evaluate the effects of dextromethorphan (DX), alone and in combination with gemcitabine (GEM), on cell viability, apoptosis, and epithelial-mesenchymal transition (EMT) markers in PANC-1 human pancreatic cancer cells. PANC-1 human pancreatic cancer cells were cultured and treated with varying concentrations of dextromethorphan (DX), gemcitabine (GEM), and 5-fluorouracil (5-FU), both as monotherapies and in combination. Cytotoxic effects were assessed using the MTT assay, and IC50 values were calculated at 24, 48, and 72 h. Apoptotic responses were evaluated using Annexin V-FITC/PI staining followed by flow cytometry. Protein expression levels of Bax, Bcl-2, and Vimentin were determined via immunocytochemistry, while EMT markers (E-cadherin, N-cadherin, Vimentin) were analyzed using flow cytometry. Relative mRNA expression of apoptotic and EMT-related genes was quantified by qRT-PCR. DX exhibited time- and dose-dependent cytotoxicity in PANC-1 cells, with IC50 values of 280.4 µM at 24 h, 163.2 µM at 48 h, and 105.6 µM at 72 h. For GEM, the 72 h IC50 was 57.53 µM. The combination of DX 50 µM + GEM 12.5 µM resulted in significantly lower cell viability (24.93 ± 3.12%) compared to GEM 25 µM (35.33 ± 5.22%) and DX 100 µM (51.40 ± 3.10%) (p < 0.001). Flow cytometry revealed significant increases in early (21.83 ± 1.32%) and late apoptotic cells (32.20 ± 0.84%) in the combination group, with a corresponding reduction in viable cells compared to control (24.93 ± 3.12% vs. 89.53 ± 0.97%, p < 0.001). Immunocytochemical analysis showed increased Bax-positive cell count (62.0 cells/unit area), and decreased Bcl-2 (19.0) and Vimentin (28.0) levels in the combination group compared to control (Bax: 15.0, Bcl-2: 60.0, Vimentin: 70.0) (p < 0.001). Flow cytometry for EMT markers demonstrated increased E-cadherin (83.84 ± 0.65%) and decreased Vimentin (71.04 ± 1.17%) and N-cadherin (30.47 ± 0.72%) expression in the DX + GEM group compared to EMT control (E-cadherin: 68.97 ± 1.43%, Vimentin: 91.00 ± 0.75%, N-cadherin: 62.47 ± 1.13%) (p < 0.001). qRT-PCR supported these findings with increased Bax (2.1-fold), E-cadherin (2.0-fold), and reduced Bcl-2 (0.3-fold) and XIAP (0.6-fold) in the combination group (p < 0.05). Dextromethorphan, particularly in combination with gemcitabine, appears to enhance apoptosis and suppress EMT-associated marker expression in PANC-1 cells, supporting its potential as an adjuvant agent in pancreatic cancer therapy.

We previously demonstrated that the activation of FGFR signaling in GIST may be a mechanism of GIST resistance to imatinib mesylate (IM). We show here that IM-resistant GIST cells lacking secondary KIT mutations overexpress claudin-1 on both transcriptional and translational levels. In contrast, a knockdown of CLDN1 or inhibition of its activity by PDS-0330 effectively restored GIST's sensitivity to IM both in vitro and in vivo. This was evidenced by the increased expression of apoptotic markers (e.g., cleaved PARP and caspase-3) and the decreased proliferation rate of IM-resistant GIST T-1R cells treated with a combination of IM and PDS-0330 (or siRNA CLDN1). In concordance with these findings, a significant synergy was observed between IM and PDS-0330 in GIST T-1R cells. Importantly, decreased tumor size and weight were observed in IM-resistant GIST xenografts treated with a combination of IM and PDS-0330. Furthermore, the combined treatment of IM-resistant tumors induced an increase in intratumoral apoptosis and other changes, as defined by the histopathologic response rate. Based on the co-immunoprecipitation and immunofluorescence microscopy data, we also demonstrated the strong interaction pattern between CLDN1 and FGFR2. Of note, the inhibition or knockdown of CLDN1 effectively decreased the phosphorylation of FGFR2 and FRS-2, a well-known FGFR adaptor protein, thereby illustrating CLDN1's ability to regulate FGFR-signaling and thereby promote FGFR-mediated survival in KIT-inhibited GIST. Consequently, CLDN1 inhibition in GIST effectively disrupted the FGFR-mediated pathway and re-sensitized tumor cells to IM. In concordance with these data, molecular profiling of CLDN1-inhibited GIST T-1R cells illustrated a significant decrease in the majority of FGFR transcripts, including FGFR2, 3, and 4. Additionally, several FGFR ligands (e.g., FGF14, -19, and -23) were also down-regulated in PDS-0330-treated GIST. Notably, exogenous FGF-2 increased CLDN1 expression in a time-dependent manner. In contrast, pan-FGFR inhibitors effectively reduced CLDN1 levels in IM-resistant GIST T-1R cells, thereby illustrating a cross-talk between CLDN1- and FGFR-mediated pathways in IM-resistant GIST. Based on subcellular fractionation and immunofluorescence microscopy data, we also observed partial relocalization of CLDN1 into the cytoplasm in IM-resistant GIST. Notably, PDS-0330 effectively abrogated this relocalization, suggesting that changes in CLDN1 subcellular distribution might also impact GIST resistance to IM. Lastly, based on our small cohort clinical study (n = 24), we observed the increased expression of CLDN1 in most "high-risk" primary GIST known to be associated with poor prognosis and aggressive behavior, thereby illustrating the prognostic value of increased CLDN1 expression in GIST and providing a further rationale to evaluate the effectiveness of CLDN1 inhibition for GIST therapy.