Ferroptosis Induction and YAP Inhibition as New Therapeutic Targets in Gastrointestinal Stromal Tumors (GISTs)

Identification and validation of protein biomarkers for predicting gastrointestinal stromal tumor recurrence

We conducted a proteomic analysis using mass spectrometry to identify and validate protein biomarkers for accurately predicting recurrence risk in gastrointestinal stromal tumors (GIST) patients, focusing on differentially expressed proteins in metastatic versus primary GIST tissues. We selected five biomarkers-GPX4, RBM4, TPM3, PFKFB2, and PGAM5-and validated their expressions in primary tumors of recurrent and non-recurrent GIST patients via immunohistochemistry. Our analysis of the association between these biomarkers with recurrence-free survival (RFS) and overall survival (OS), along with their interrelationships, revealed that immunohistochemistry confirmed significantly higher expressions of these biomarkers in primary GIST tissues of recurrent patients. Kaplan-Meier survival analysis showed that high expressions of GPX4, RBM4, TPM3, PFKFB2, and PGAM5 correlated with lower RFS, and GPX4 and RBM4 with lower OS. All biomarker pairs showed positive associations, with high expressions correlating with increased recurrence rates, and GPX4 and RBM4 with higher mortality rates. In conclusion, the biomarkers GPX4, RBM4, TPM3, PFKFB2, and PGAM5 are clinically relevant for predicting GIST recurrence, with their high expressions in primary tumors linked to poorer RFS and OS. They serve as potential prognostic indicators, enabling early treatment and improved outcomes. The observed interrelationships among these biomarkers further validate their accuracy in predicting GIST recurrence.

USP7 upregulated by TGF-β1 promotes ferroptosis via inhibiting LATS1-YAP axis in sepsis-induced acute lung injury

Our work aimed to investigate the interactive roles of transforming growth factor β1 (TGF-β1), ubiquitin-specific-processing protease 7 (USP7), and Yes-associated protein (YAP) in ferroptosis during sepsis-secondary acute lung injury (ALI). Our study demonstrated that ferroptosis was aggravated by TGF-β1 in both cellular and animal models of acute lung injury. Additionally, YAP upregulated glutathione peroxidase 4 (GPX4) and SLC7A11 by regulating the binding of TEAD4 to GPX4/SLC7A11 promoters. Furthermore, large tumor suppressor kinase 1 (LATS1) knockdown resulted in YAP expression stimulation, while USP7 downregulated YAP via deubiquitinating and stabilizing LATS1/2. YAP overexpression or USP7/LATS1 silencing reduced ferroptosis process, which regulated YAP through a feedback loop. However, TGF-β1 annulled the repression of ferroptosis by YAP overexpression or LATS1/USP7 knockdown. By elucidating the molecular interactions between TGF-β1, USP7, LATS1/2, and YAP, we identified a new regulatory axis of ferroptosis in sepsis-secondary ALI. Our study sheds light on the pathophysiology of ferroptosis and proposes a potential therapeutic approach for sepsis-induced ALI.

ANO6 (TMEM16F) inhibits gastrointestinal stromal tumor growth and induces ferroptosis

Herein, we elucidate the potential role of ANO6 (TMEM16F) in gastrointestinal stromal tumors (GISTs). ANO6 expression in GIST and adjacent normal tissues was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Cell proliferation, apoptosis, and pyroptosis were examined utilizing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, terminal deoxynucleotidyl transferase dUTP Nick-End Labeling staining, and flow cytometry. In addition, the total iron and Fe2+ levels were assessed. IL-18 and IL-1β levels were also evaluated. Lipid reactive oxygen species (ROS), cystine (Cys), glutathione (GSH), and glutathione peroxidase 4 (GPX4) levels were evaluated using appropriate kits. Ferroptotic markers, including Ptgs2, Chac1, SLC7A11, and SLC3A2, were analyzed by RT-qPCR, western blotting, and immunohistochemistry. ANO6 expression decreased in GIST tissues. ANO6-plasmid inhibits proliferation, induces apoptosis, and promotes pyroptosis in GIST-T1 and GIST-T1 IR cells. The ANO6-plasmid induced ferroptosis, as confirmed by enhanced lipid ROS levels, increased intracellular concentrations of total iron and Fe2+, promoted Ptgs2 and Chac1 expression, reduced Cys, GSH, and GPX4 levels, and downregulated SLC7A11 and SLC3A2 expression after in vitro and in vivo treatment with ANO6-plasmid. Moreover, the ANO6-plasmid inhibited GIST growth in vivo. Therefore, ANO6 may be a promising therapeutic target for blocking the development of GIST via the induction of apoptosis, pyroptosis, and ferroptosis.

TRIM21/USP15 balances ACSL4 stability and the imatinib resistance of gastrointestinal stromal tumors

BACKGROUND

Imatinib has become an exceptionally effective targeted drug for treating gastrointestinal stromal tumors (GISTs). Despite its efficacy, the resistance to imatinib is common in GIST patients, posing a significant challenge to the effective treatment.

METHODS

The expression profiling of TRIM21, USP15, and ACSL4 in GIST patients was evaluated using Western blot and immunohistochemistry. To silence gene expression, shRNA was utilized. Biological function of TRIM21, USP15, and ACSL4 was examined through various methods, including resistance index calculation, colony formation, shRNA interference, and xenograft mouse model. The molecular mechanism of TRIM21 and USP15 in GIST was determined by conducting Western blot, co-immunoprecipitation, and quantitative real-time PCR (qPCR) analyses.

RESULTS

Here we demonstrated that downregulation of ACSL4 is associated with imatinib (IM) resistance in GIST. Moreover, clinical data showed that higher levels of ACSL4 expression are positively correlated with favorable clinical outcomes. Mechanistic investigations further indicated that the reduced expression of ACSL4 in GIST is attributed to excessive protein degradation mediated by the E3 ligase TRIM21 and the deubiquitinase USP15.

CONCLUSION

These findings demonstrate that the TRIM21 and USP15 control ACSL4 stability to maintain the IM sensitive/resistant status of GIST.

KIT-SNAP-tag/cell membrane chromatography model coupled with liquid chromatography-mass spectrometry for anti-GIST compound screening from Evodia rutaecarpa

Gastrointestinal mesenchymal tumors, as the most common mesenchymal tumors in the gastrointestinal tract, are adjuvantly treated with multi-targeted tyrosine kinase inhibitors, such as imatinib and sunitinib, but there are problems of drug resistance and complex methods of monitoring therapeutic agents. The pathogenesis of this disease is related to mutations in tyrosine kinase (KIT) or platelet-derived growth factor receptor α, an important target for drug therapy. In recent years, the screening of relevant tyrosine kinase inhibitors from traditional Chinese medicine has become a hotspot in antitumor drug research. In the current study, the KIT-SNAP-tag cell membrane chromatography (KIT-SNAP-tag/CMC) column was prepared with satisfying specificity, selectivity, and reproducibility by chemically bonding high KIT expression cell membranes to the silica gel surface using the SNAP-tag technology. The KIT-SNAP-tag/CMC-HPLC-MS two-dimensional coupling system was investigated using the positive drug imatinib, and the results showed that the system was a reliable model for screening potential antitumor compounds from complex systems. This system screened and identified three potential active compounds of evodiamine (EVO), rutaecarpin (RUT), and dehydroevodiamine (DEVO), which possibly target the KIT receptor, from the alcoholic extract of the traditional Chinese medicine Evodia rutaecarpa. Then, the KD values of the interaction of EVO, RUT, and DEVO with KIT receptors measured using nonlinear chromatography were 7.75 (±4.93) × 10-6, 1.42 (±0.71) × 10-6, and 2.34 (±1.86) × 10-6 mol/L, respectively. In addition, the methyl thiazolyl tetrazolium assay validated the active effects of EVO and RUT in inhibiting the proliferation of high KIT-expressing cells in the ranges of 0.1-10 µmol/L and 0.1-50 µmol/L, respectively. In conclusion, the KIT-SNAP-tag/CMC could be a reliable model for screening antitumor components from complex systems.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Bisphenol A induces placental ferroptosis and fetal growth restriction via the YAP/TAZ-ferritinophagy axis

Exposure to bisphenol A (BPA) during gestation leads to fetal growth restriction (FGR), whereby the underlying mechanisms remain unknown. Here, we found that FGR patients showed higher levels of BPA in the urine, serum, and placenta; meanwhile, trophoblast ferroptosis was observed in FGR placentas, as indicated by accumulated intracellular iron, impaired antioxidant molecules, and increased lipid peroxidation products. To investigate the role of ferroptosis in placental and fetal growth, BPA stimulation was performed both in vivo and in vitro. BPA exposure during gestation was associated with FGR in mice; also, it induces ferroptosis in mouse placentas and human placental trophoblast. Pretreatment with ferroptosis inhibitor ferritin-1 (Fer-1) alleviated BPA-induced oxidative damage and cell death. Notably, BPA reduced the trophoblastic expression of Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), which regulated tissue growth and organ size. YAP or TAZ siRNA enhanced BPA-induced ferroptosis, suggesting that trophoblast ferroptosis is dependent on YAP/TAZ downregulation after BPA stimulation. Consistently, the protein levels of YAP/TAZ were also reduced in FGR placentas. Further results revealed that silencing YAP/TAZ promoted BPA-induced ferroptosis through autophagy. Pretreatment with autophagy inhibitor chloroquine (CQ) attenuated BPA-induced trophoblast ferroptosis. Ferritinophagy, an autophagic degradation of ferritin (FTH1), was observed in FGR placentas. Similarly, BPA reduced the protein level of FTH1 in placental trophoblast. Pretreatment with iron chelator desferrioxamine (DFO) and NCOA4 (an autophagy cargo receptor) siRNA weakened the ferroptosis of trophoblast after exposure to BPA, indicating that autophagy mediates ferroptosis in BPA-stimulated trophoblast by degrading ferritin. In summary, ferroptosis was featured in BPA-associated FGR and trophoblast injury; the regulation of ferroptosis involved the YAP/TAZ-autophagy-ferritin axis.

Ferroptosis: An Emerging Target for Bladder Cancer Therapy

Bladder cancer (BC), as one of the main urological cancers in the world, possesses the abilities of multiple-drug resistance and metastasis. However, there remains a significant gap in the understanding and advancement of prognosis and therapeutic strategies for BC. Ferroptosis, a novel type of iron-dependent regulated cell death, depends on lipid peroxidation, which has been proven to have a strong correlation with the development and treatment of BC. Its mechanism mainly includes three pathways, namely, lipid peroxidation, the antioxidant system, and the iron overload pathway. In this review, we reviewed the mechanism of ferroptosis, along with the related therapeutic targets and drugs for BC, as it might become a new anticancer treatment in the future.

Verteporfin Exerts Anticancer Effects and Reverses Resistance to Paclitaxel via Inducing Ferroptosis in Esophageal Squamous Cell Cancer Cells

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors. Ferroptosis is a new form of regulated cell death and targeting ferroptosis provides a novel therapeutic approach for human cancers. Verteporfin (VP) has been identified as a Yes-associated protein (YAP) inhibitor for treatment of several human cancers. However, it remains unclear whether VP exerts anticancer activity by inducing ferroptosis in ESCC cells. In the current study, we found that VP reduced cell viability and led to cell death in ESCC cell lines (KYSE150 and KYSE30) by inhibiting YAP expression. Subsequently, the findings revealed that VP treatment triggered significant ferroptosis events, including accumulation of Fe2+, reactive oxygen species (ROS) and malondialdehyde (MDA), reduction of mitochondrial membrane potential (MMP), glutathione (GSH) and glutathione peroxidase 4 (GPX4) expression. Further study showed that the effects of ESCC cell proliferation and death caused by VP could be reversed by ferroptosis inhibitor ferrostatin-1 (Fer-1). Moreover, VP enhanced the chemosensitivity of ESCC resistant cells to paclitaxel (PTX). And VP combined with PTX can synergistically inhibit cell proliferation and induce cell death by triggering ferroptosis of PTX-resistant cells. All these data suggested that VP suppressed ESCC cell survival and reversed resistance to PTX through inducing ferroptosis, which may provide a promising therapeutic strategy for ESCC.

The impact of interaction between verteporfin and yes-associated protein 1/transcriptional coactivator with PDZ-binding motif-TEA domain pathway on the progression of isocitrate dehydrogenase wild-type glioblastoma

Verteporfin and 5-ALA are used for visualizing malignant tissue components in different body tumors and as photodynamic therapy in treating isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM). Additionally, verteporfin interferes with Yes-associated protein 1 (YAP)/Transcriptional coactivator with PDZ-binding motif - TEA domain (TAZ-TEAD) pathway, thus inhibiting the downstream effect of these oncogenes and reducing the malignant properties of GBM. Animal studies have shown verteporfin to be successful in increasing survival rates, which have led to the conduction of phase 1 and 2 clinical trials to further investigate its efficacy in treating GBM. In this article, we aimed to review the novel mechanism of verteporfin's action, the impact of its interaction with YAP/TAZ-TEAD, its effect on glioblastoma stem cells, and its role in inducing ferroptosis.

Ferroptosis-Mediated Cell Death Induced by NCX4040, The Non-Steroidal Nitric Oxide Donor, in Human Colorectal Cancer Cells: Implications in Therapy

Our recent studies show that the treatment of human ovarian tumor cells with NCX4040 results in significant depletions of cellular glutathione, the formation of reactive oxygen/nitrogen species and cell death. NCX4040 is also cytotoxic to several human colorectal cancer (CRC) cells in vitro and in vivo. Here, we examined the ferroptosis-dependent mechanism(s) of cytotoxicity of NCX4040 in HT-29 and K-RAS mutant HCT 116 colon cell lines. Ferroptosis is characterized by the accumulation of reactive oxygen species (ROS) within the cell, leading to an iron-dependent oxidative stress-mediated cell death. However, its relevance in the mechanism of NCX4040 cytotoxicity in CRCs is not known. We found that NCX4040 generates ROS in CRC cells without any depletion of cellular GSH. Combinations of NCX4040 with erastin (ER) or RSL3 (RAS-selective lethal 3), known inducers of ferroptosis, enhanced CRC death. In contrast, ferrostatin-1, an inhibitor of ferroptosis, significantly inhibited NCX4040-induced cell death. Treatment of CRC cells with NCX4040 resulted in the induction of lipid peroxidation in a dose- and time-dependent manner. NCX4040 treatment induced several genes related to ferroptosis (e.g., CHAC1, GPX4 and NOX4) in both cell lines. Metabolomic studies also indicated significant increases in both lipid and energy metabolism following the drug treatment in HT-29 and HCT 116 cells. These observations strongly suggest that NCX4040 causes the ferroptosis-mediated cell death of CRC cells. Furthermore, combinations of NCX4040 and ER or RSL3 may contribute significantly to the treatment of CRC, including those that are difficult to treat due to the presence of Ras mutations in the clinic. NCX4040-induced ferroptosis may also be a dynamic form of cell death for the treatment of other cancers.

Studying the Geroprotective Properties of YAP/TAZ Signaling Inhibitors on Drosophila melanogaster Model

The transcriptional coactivators Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are the main downstream effectors of the evolutionarily conserved Hippo signaling pathway. YAP/TAZ are implicated in the transcriptional regulation of target genes that are involved in a wide range of key biological processes affecting tissue homeostasis and play dual roles in the aging process, depending on the cellular and tissue context. The aim of the present study was to investigate whether pharmacological inhibitors of Yap/Taz increase the lifespan of Drosophila melanogaster. Real-time qRT-PCR was performed to measure the changes in the expression of Yki (Yorkie, the Drosophila homolog of YAP/TAZ) target genes. We have revealed a lifespan-increasing effect of YAP/TAZ inhibitors that was mostly associated with decreased expression levels of the wg and E2f1 genes. However, further analysis is required to understand the link between the YAP/TAZ pathway and aging.