Type Of Non-apoptotic Cell Death Research Articles

New Treatment Modalities for Colorectal Cancer Through Simultaneous Suppression of FSP1 and GPX4.

Ferroptosis is a nonapoptotic type of cell death that is dependent on iron and involves the accumulation of reactive oxygen species. Ferroptosis suppressor protein 1 (FSP1) and glutathione peroxidase 4 (GPX4) are ferroptosis regulators that inhibit ferroptosis through independent pathways. This study assessed the prognostic value of GPX4 and FSP1 expression in colorectal cancer (CRC). We also examined the effects of FSP1 and GPX4 inhibition on cell survival of CRC cells. This study included 206 surgical specimens from Stage II or III CRC patients. FSP1 and GPX4 expression was analyzed immunohistochemically, and the association of their expression levels with clinical outcome was evaluated. We also examined the effects of FSP1 and GPX4 inhibitors on the cell proliferative capacity of CRC cell lines. Overall survival and recurrence-free survival were reduced in patients with high expression of FSP1 or GPX4, and those with both GPX4 and FSP1 expression showed worse prognosis. Positivity of both FSP1 and GPX4 was an independent poor prognostic factor for CRC patients. In CRC cells, the combination of GPX4 and FSP1 inhibitors led to more effective cell death than either inhibitor alone. High expression of both GPX4 and FSP1 is a significant poor prognostic factor for CRC. Simultaneous inhibition of GPX4 and FSP1 to induce ferroptosis may be a novel therapeutic strategy in CRC.

Novel Thienopyrimidine-Hydrazinyl Compounds Induce DRP1-Mediated Non-Apoptotic Cell Death in Triple-Negative Breast Cancer Cells.

Apoptosis induction with taxanes or anthracyclines is the primary therapy for TNBC. Cancer cells can develop resistance to anticancer drugs, causing them to recur and metastasize. Therefore, non-apoptotic cell death inducers could be a potential treatment to circumvent apoptotic drug resistance. In this study, we discovered two novel compounds, TPH104c and TPH104m, which induced non-apoptotic cell death in TNBC cells. These lead compounds were 15- to 30-fold more selective in TNBC cell lines and significantly decreased the proliferation of TNBC cells compared to that of normal mammary epithelial cell lines. TPH104c and TPH104m induced a unique type of non-apoptotic cell death, characterized by the absence of cellular shrinkage and the absence of nuclear fragmentation and apoptotic blebs. Although TPH104c and TPH104m induced the loss of the mitochondrial membrane potential, TPH104c- and TPH104m-induced cell death did not increase the levels of cytochrome c and intracellular reactive oxygen species (ROS) and caspase activation, and cell death was not rescued by incubating cells with the pan-caspase inhibitor, carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoromethylketone (Z-VAD-FMK). Furthermore, TPH104c and TPH104m significantly downregulated the expression of the mitochondrial fission protein, DRP1, and their levels determined their cytotoxic efficacy. Overall, TPH104c and TPH104m induced non-apoptotic cell death, and further determination of their cell death mechanisms will aid in the development of new potent and efficacious anticancer drugs to treat TNBC.

Oxidative Metabolism as a Cause of Lipid Peroxidation in the Execution of Ferroptosis.

Ferroptosis is a type of nonapoptotic cell death that is characteristically caused by phospholipid peroxidation promoted by radical reactions involving iron. Researchers have identified many of the protein factors that are encoded by genes that promote ferroptosis. Glutathione peroxidase 4 (GPX4) is a key enzyme that protects phospholipids from peroxidation and suppresses ferroptosis in a glutathione-dependent manner. Thus, the dysregulation of genes involved in cysteine and/or glutathione metabolism is closely associated with ferroptosis. From the perspective of cell dynamics, actively proliferating cells are more prone to ferroptosis than quiescent cells, which suggests that radical species generated during oxygen-involved metabolism are responsible for lipid peroxidation. Herein, we discuss the initial events involved in ferroptosis that dominantly occur in the process of energy metabolism, in association with cysteine deficiency. Accordingly, dysregulation of the tricarboxylic acid cycle coupled with the respiratory chain in mitochondria are the main subjects here, and this suggests that mitochondria are the likely source of both radical electrons and free iron. Since not only carbohydrates, but also amino acids, especially glutamate, are major substrates for central metabolism, dealing with nitrogen derived from amino groups also contributes to lipid peroxidation and is a subject of this discussion.

PRMT4 interacts with NCOA4 to inhibit ferritinophagy in cisplatin-induced acute kidney injury.

Cisplatin-induced acute kidney injury (AKI) is commonly seen in the clinical practice, and ferroptosis, a type of non-apoptotic cell death, plays a pivotal role in it. Previous studies suggested that protein arginine methyltransferase 4 (PRMT4) was incorporated in various bioprocesses, but its role in renal injuries has not been investigated. Our present study showed that PRMT4 was highly expressed in renal proximal tubular cells, and it was downregulated in cisplatin-induced AKI. Besides, genetic disruption of PRMT4 exacerbated, while its overexpression attenuated, cisplatin-induced redox injuries in renal proximal epithelia. Mechanistically, our work showed that PRMT4 interacted with NCOA4 to inhibit ferritinophagy, a type of selective autophagy favoring lipid peroxidation to accelerate ferroptosis. Taken together, our study demonstrated that PRMT4 interacted with NCOA4 to attenuate ferroptosis in cisplatin-induced AKI, suggesting that PRMT4 might present as a new therapeutic target for cisplatin-related nephropathy.

Prognostic significance of pyroptosis-associated molecules in endometrial cancer: a comprehensive immunohistochemical analysis.

Endometrial cancer, the most prevalent malignancy of the female genital tract, has a concerningly poor prognosis when diagnosed in advanced stages, with limited targeted therapy options available for advanced or recurrent cases. Pyroptosis, a type of nonapoptotic cell death mediated by caspase-1, has shown potential antitumor effects in various tumors. NLRP3, a cytosolic sensor, initiates the canonical pyroptotic pathway, leading to caspase-1 activation, subsequent gasdermin D cleavage, and plasma membrane pore formation. The ESCRT-III machinery, particularly CHMP4B, acts as a key inhibitor of pyroptosis by repairing gasdermin D-induced membrane damage. The current study aimed to evaluate the clinicopathologic relevance of key pyroptosis-associated molecules in endometrial cancer. Immunohistochemistry was used to assess the expression of four pyroptosis-associated molecules (NLRP3, cleaved caspase-1 p20, cleaved gasdermin D, and CHMP4B) in 351 patients with endometrial cancer, and their associations with clinical, pathological, and survival outcomes were analyzed. High NLRP3 expression was significantly associated with age ≤ 50 years and premenopause. Increased cleaved caspase-1 p20 expression was associated with nonendometrioid carcinoma, Federation of Gynaecology and Obstetrics (FIGO) grade 3, and the p53 mutant pattern and was independently associated with poor recurrence-free survival (RFS) and overall survival. Increased cleaved gasdermin D expression was associated with a body mass index of >25 kg/m², FIGO grades 1-2, early FIGO stage (I-II), and absence of lymph node metastasis. High CHMP4B expression was associated with nonendometrioid carcinoma and poor RFS. Cleaved gasdermin D-high/CHMP4B-low endometrial cancer was associated with endometrioid carcinoma, FIGO grades 1-2 and favorable RFS. Our study identified cleaved caspase-1 p20 as an independent predictor of adverse outcomes in endometrial cancer. CHMP4B, an inhibitor of pyroptosis, was associated with an unfavorable RFS, whereas high cleaved gasdermin D/low CHMP4B expression was associated with a favorable RFS. These findings underscore the prognostic significance of pyroptosis and the potential interaction between cleaved gasdermin D and CHMP4B in endometrial cancer.

A PANoptosis pattern to predict prognosis and immunotherapy response in head and neck squamous cell carcinoma

Individuals diagnosed with head and neck squamous cell carcinoma (HNSCC) experience a significant occurrence rate and are susceptible to premature spreading, resulting in a bleak outlook. Therapeutic approaches, such as chemotherapy, targeted therapy, and immunotherapy, may exhibit primary and acquired resistance during the advanced phases of HNSCC. There is currently no viable solution to tackle this issue. PANoptosis—a type of non-apoptotic cell death—is a recently identified mechanism of cellular demise that entails communication and synchronization among thermal apoptosis, apoptosis, and necrosis mechanisms. However, the extent to which PANoptosis-associated genes (PRG) contribute to the forecast and immune reaction of HNSCC remains mostly undisclosed. The present study aimed to thoroughly analyze the potential importance of PRG in HNSCC and report our discoveries. We systematically analyzed 19 PRG from previous studies and clinical data from HNSCC patients to establish a PAN-related signature and assess its prognostic, predictive potential. Afterward, the patient information was separated into two gene patterns that corresponded to each other, and the analysis focused on the connection between patient prognosis, immune status, and cancer immunotherapy. The PAN score was found to correlate with survival rates, immune systems, and cancer-related pathways. We then validated the malignant role of CD27 among them in HNSCC. In summary, we demonstrated the effectiveness of PAN.Score-based molecular clustering and prognostic features in predicting the outcome of HNSCC. The discovery we made could enhance our comprehension of the significance of PAN.Score in HNSCC and facilitate the development of more effective treatment approaches.

Gut Microbiome Mediates Ferroptosis Resistance for Colorectal Cancer Development.

Colorectal cancer is a prevalent cancer type in the United States, affecting both genders and influenced by genetics and environmental factors. The role of the gut microbiome in colorectal cancer development and therapy response is a burgeoning field of study. A recent study uncovered that trans-3-indoleacrylic acid (IDA), a microbial metabolite from P. anaerobius, promotes colorectal cancer by inhibiting ferroptosis, a type of nonapoptotic cell death driven by unrestricted lipid peroxidation and subsequent membrane damage. IDA activates aryl hydrocarbon receptor (AHR), a nuclear transcription factor, leading to the expression of aldehyde dehydrogenase 1 family member A3 (ALDH1A3). ALDH1A3, known for aldehyde detoxification, also contributes to ferroptosis resistance by generating reduced nicotinamide adenine dinucleotide (NADH), critical for the synthesis of reduced coenzyme Q10 (COQH10), by apoptosis-inducing factor mitochondria-associated 2 (AIFM2, also known as FSP1). Knocking out AHR, AIFM2, or ALDH1A3 reverses the inhibitory effect of IDA on ferroptosis and IDA-mediated tumor growth. Significantly, P. anaerobius is enriched in patients with colorectal cancer, and supplementing IDA or P. anaerobius accelerates colorectal cancer progression in spontaneous or orthotopic mouse models. Taken together, these findings suggest that targeting P. anaerobius-mediated ferroptosis resistance emerges as a promising strategy to combat colorectal cancer development.

Berberine-mediated Ferroptosis through System Xc-/GSH/GPX4 Axis Inhibits Metastasis of Nasopharyngeal Carcinoma.

Nasopharyngeal carcinoma (NPC) is a malignant tumor that is highly prevalent in Southeast China, and its metastasis remains an unresolved clinical problem. Ferroptosis, a type of nonapoptotic cell death, is a critical pathway in tumor metastasis. Berberine (BBR), a plant alkaloid, has been explored as a potential anti-NPC metastatic agent; however, the underlying mechanisms are unknown. Here, we showed that BBR exerted its anti-metastasis role by inhibiting system Xc-/GSH/GPX4 axis-driven ferroptosis. The present study demonstrated for the first time that BBR induced ferroptosis in NPC cells by increasing reactive oxygen species, lipid peroxidation and cellular Fe2+ and that the ferroptosis inhibitors Ferrostatin-1 and Deferoxamine mesylate rescued BBR-induced NPC cell death. Moreover, the ferroptotic characteristics of BBR-treated NPC cells were observed using transmission electron microscopy. Mechanistically, system Xc- (SLC7A11 and SLC3A2) and GSH levels were found to be suppressed after treatment with BBR. We demonstrated that the system Xc-/GSH/GPX4 axis was a critical mediator of BBR-induced ferroptosis. Furthermore, GPX4, a key inhibitor of lipid peroxidation, was greatly suppressed by BBR at both protein and mRNA levels. Molecular docking results showed a strong interaction between GPX4 and BBR. Notably, GPX4 overexpression reversed the effect of BBR-induced ferroptosis in NPC cells. Finally, BBR-mediated inhibition of NPC metastasis was validated in vivo using a mouse model. Taken together, our data suggest that BBR induced ferroptosis of NPC cells via suppressing the system Xc-/GSH/GPX4 axis, provides new insights into the mechanism of BBR anti-NPC metastasis.

A novel microtubule inhibitor promotes tumor ferroptosis by attenuating SLC7A11/GPX4 signaling

MP-HJ-1b is a novel microtubule inhibitor that we designed and reported previously. Ferroptosis is a newly identified type of nonapoptotic cell death induced by ferrous catalysis and lipid peroxidation. Here, transcriptomics, proteomics, and molecular docking analyses were combined to explore the novel effects of MP-HJ-1b on tumors. Both omics analyses suggested that MP-HJ-1b affects ribosomes, and we confirmed that it inhibits the ribosomal component proteins RPL35 and MRPL28. Colchicine was used as an analog, and the results showed that MP-HJ-1b and colchicine increased reactive oxygen species and malondialdehyde levels and decreased reduced glutathione levels, suggesting that they promoted ferroptosis in HeLa cells. Specifically, MP-HJ-1b downregulated SLC7A11 and GPX4 to enhance the classical pathway of ferroptosis, while colchicine upregulated LC3A/B-II and enhanced autophagy. Clinically, the serum concentrations of ferrous ions, reduced glutathione, and Hcy were higher in cervical cancer patients than in healthy individuals. ALT, AST, Cho, HDL-C, and LDL-C levels were decreased in the serum of patients. Our study expands understanding of the way MP-HJ-1b promotes cell death and enriches research on microtubule inhibitors in the ferroptosis field.

Molecular mechanisms of ferroptosis and its roles in leukemia.

Cell death is a complex process required to maintain homeostasis and occurs when cells are damage or reach end of life. As research progresses, it is apparent that necrosis and apoptosis do not fully explain the whole phenomenon of cell death. Therefore, new death modalities such as autophagic cell death, and ferroptosis have been proposed. In recent years, ferroptosis, a new type of non-apoptotic cell death characterized by iron-dependent lipid peroxidation and reactive oxygen species (ROS) accumulation, has been receiving increasing attention. Ferroptosis can be involved in the pathological processes of many disorders, such as ischemia-reperfusion injury, nervous system diseases, and blood diseases. However, the specific mechanisms by which ferroptosis participates in the occurrence and development of leukemia still need to be more fully and deeply studied. In this review, we present the research progress on the mechanism of ferroptosis and its role in leukemia, to provide new theoretical basis and strategies for the diagnosis and treatment of clinical hematological diseases.

Melatonin protects photoreceptor cells against ferroptosis in dry AMD disorder by inhibiting GSK-3B/Fyn-dependent Nrf2 nuclear translocation

BackgroundFerroptosis is a type of non-apoptotic cell death that relies on iron ions and reactive oxygen species to induce lipid peroxidation. This study aimed to determine whether ferroptosis exists in the pathogenesis of dry age-related macular degeneration (AMD) and to confirm that melatonin (MLT) suppresses the photoreceptor cell ferroptosis signaling pathway. MethodsWe exposed 661W cells to sodium iodate (NaIO3) in vitro and treated them with different concentrations of MLT. In vivo, C57BL/6 mice were given a single caudal vein injection of NaIO3, followed by an intraperitoneal injection of MLT, and eyeballs were taken for subsequent trials. ResultsWe found that NaIO3 could induce photoreceptor cell death and lipid peroxide accumulation, and result in changes in the expression of ferroptosis-related factors and iron maintenance proteins, which were treated by MLT. We further demonstrated that MLT can block Fyn-dependent Nrf2 nuclear translocation by suppressing the GSK-3β signaling pathway. In addition, the therapeutic effect of MLT was significantly inhibited when Nrf2 was silenced. ConclusionsOur findings provide a novel insight that NaIO3 induces photoreceptor cell ferroptosis in dry AMD and suggest that MLT has therapeutic effects by suppressing GSK-3β/Fyn-dependent Nrf2 nuclear translocation.

LncFASA promotes cancer ferroptosis via modulating PRDX1 phase separation.

Ferroptosis, a unique type of non-apoptotic cell death resulting from iron-dependent lipid peroxidation, has a potential physiological function in tumor suppression, but its underlying mechanisms have not been fully elucidated. Here, we report that the long non-coding RNA (lncRNA) LncFASA increases the susceptibility of triple-negative breast cancer (TNBC) to ferroptosis. As a tumor suppressor, LncFASA drives the formation of droplets containing peroxiredoxin1 (PRDX1), a member of the peroxidase family, resulting in the accumulation of lipid peroxidation via the SLC7A11-GPX4 axis. Mechanistically, LncFASA directly binds to the Ahpc-TSA domain of PRDX1, inhibiting its peroxidase activity by driving liquid-liquid phase separation, which disrupts intracellular ROS homeostasis. Notably, high LncFASA expression indicates favorable overall survival in individuals with breast cancer, and LncFASA impairs the growth of breast xenograft tumors by modulating ferroptosis. Together, our findings illustrate the crucial role of this lncRNA in ferroptosis-mediated cancer development and provide new insights into therapeutic strategies for breast cancer.

Kaempferol stimulation of autophagy regulates the ferroptosis under the oxidative stress as mediated with AMP-activated protein kinase

Recent studies have highlighted the positive effects of Kaempferol (KP), including its anti-inflammatory and antioxidant properties. However, its impact on oxidative damage induced by heavy metals and pro-inflammatory mediators, such as arachidonic acid (AA), has not yet been identified. Our objective was to specifically evaluate liver damage due to AA + iron-induced oxidative stress, both in vitro and in vivo. In HepG2 cells, KP activated the AMP-activated protein kinase (AMPK), suggesting a hepatoprotective effect through AMPK inhibition, as assessed by immunoblot and FACS analysis (EC50 = 10 μM). KP also stimulated autophagy, a degradation process that eliminates aged, damaged, and unnecessary components, via mTOR inhibition and ULK1 phosphorylation. This activation was further validated by the upregulation of autophagy-related genes (ATG5) and Beclin-1, along with the conversion of LC3BI to LC3BII. Ferroptosis, a non-apoptotic type of cell death characterized by oxidative stress from the production of reactive oxygen species (ROS) and excessive iron accumulation, was linked to the activation of autophagy, as confirmed through the protein expression of deferoxamine (DFO) and ferrostatin-1 (Fer-1), the representative ferroptosis inhibitors (positive controls). In mice, oral administration of KP demonstrated protective effects against CCl4-induced hepatotoxicity. In conclusion, KP provides hepatoprotective effects against oxidative stress induced by AA + iron treatment in vitro and CCl4 treatment in vivo.

Neutrophil Membrane-Inspired Nanorobots Act as Antioxidants Ameliorate Ischemia Reperfusion-Induced Acute Kidney Injury.

Ischemia/reperfusion (I/R) injury causes excessive oxidative events and initiates destructive inflammatory responses, and it is an important promoter to the pathology of various pathema states. Ferroptosis is an iron-dependent type of nonapoptotic cell death accompanied by the accumulation of membrane lipid peroxide and consumption of polyunsaturated fatty acid, and it plays a key role in I/R injury diseases. Moreover, the excessive production of inflammatory cytokines contributes to the development of acute kidney injury. Here, we reported neutrophil membrane-coated copper-based nanoparticles (N-Cu5.4O@DFO NPs) for I/R kidney injury treatment. The highly biocompatible and stable N-Cu5.4O@DFO NPs showed excellent antioxidant and iron ion scavenging abilities in vitro. Our finding showed that the N-Cu5.4O@DFO NPs strategy could significantly accumulate in the inflammatory kidney, reduce oxidative damage events and inflammatory response, and finally achieve synergistic therapy against renal I/R injury. This work promotes the development of nanoantioxidant agents with multiple antioxidant properties for the therapy of other I/R injury diseases.

Gallium Triggers Ferroptosis through a Synergistic Mechanism.

The gallium ion (Ga3+ ) has long been believed to disrupt ferric homeostasis in the body by competing with iron cofactors in metalloproteins, ultimately leading to cell death. This study revealed that through an indirect pathway, gallium can trigger ferroptosis, a type of non-apoptotic cell death regulated by iron. This is exemplified by the gallium complex of the salen ligand (Ga-1); we found that Ga-1 acts as an effective anion transporter that can affect the pH gradient and change membrane permeability, leading to mitochondrial dysfunction and the release of ferrous iron from the electron transfer chain (ETC). In addition, Ga-1 also targeted protein disulfide isomerases (PDIs) located in the endoplasmic reticulum (ER) membrane, preventing the repair of the antioxidant glutathione (GSH) system and thus enforcing ferroptosis. Finally, a combination treatment of Ga-1 and dietary polyunsaturated fatty acids (PUFAs), which enhances lipid peroxidation during ferroptosis, showed a synergistic therapeutic effect both in vitro and in vivo. This study provided us with a strategy to synergistically induce Ferroptosis in tumor cells, thereby enhancing the anti-neoplastic effect.

Iron ion and siramesine-loaded polydopamine nanoparticles forenhanced breast cancer therapy

Ferroptosis is a novel type of nonapoptotic cell death, showing a hopeful potential in cancer therapeutic schedules. Oneof the apparent features of ferroptosis is the lipid hydroperoxides producing ROS induced by intracellular iron ionsaccumulation. Thus the iron regulation and metabolism in the cell is an essential factors for the trigger of ferroptosis.We designed a new nanoparticle that loaded ferric ions and siamese based on polydopamine nanomaterial (siramesine@Fe(III) PDA NPs) to induce breast cancer ferroptosis through the Fenton reaction. Iron ions can be added to cancer cells,and siamese can block the exportation of intracellular iron by inhibiting the expression of FPN, thus promoting theFenton reaction. The extra transport of iron ions into cells by nanoparticles and the inhibition of iron ions outward bySiramesine promoted the accumulation of iron ions in cells, thus achieving a synergistic effect leading to ferroptosis incells. In addition, NPs demonstrated excellent pH-responsive degradation, with enhanced drug release at the pH valueof tumor microenvironments and lysosomal. Siramesine@Fe(III) PDA NPs showed good ferroptosis induction ability,displaying the potential for cancer treatment.

Abstract 6139: Clinical implication of EZH2 inhibitors in hepatocellular carcinoma

Abstract Background & Aim: Aberrant upregulation of EZH2 is frequently observed in hepatocellular carcinoma (HCC) and significantly associated with poor prognosis of HCC patients. While EZH2 inhibitors (EZH2i) are recently approved for treatment of lymphoma and sarcoma, their antitumor effect alone is not optimally efficacious against solid tumors like HCC. Ferroptosis is a newly discovered nonapoptotic type of cell death characterized by the iron-dependent accumulation of lipid hydroperoxides in cell membrane to lethal levels. Owing to anti-cancer effects of ferroptosis, many oncogenes are known to suppress ferroptosis. However, their mechanisms in HCC are currently unknown. We aim to uncover a novel mechanism for EZH2-mediated resistance to ferroptosis in HCC. Methods: Multi-step analyses were performed with genomic data from mouse models (Ezh1/2 KO), cancer cell lines treated with EZH2i GSK126, and primary tumors including HCC to identify genetic networks or signaling/metabolic pathways associated with EZH2 in cancer cells. Functional connection of identified networks or pathways from the prediction analyses was tested in cell line models with various molecular biology approaches including western blots, colony forming assay, overexpression and/or depletion of genes of interest. Results: Gene network analysis predicted that ferroptosis pathway is inhibited by EZH2. Interestingly, lipid biosynthesis is also identified as an inhibited metabolic pathway by EZH2. Since polyunsaturated fatty acid (PUFA) is essential for executing ferroptosis, we hypothesize that EZH2 suppresses ferroptosis by inhibiting synthesis of PUFA. HCC cells with high EZH2 expression have higher IC50 values to erastin, a ferroptosis inducer, than those with low EZH2 expression. Moreover, inhibition or depletion of EZH2 sensitize HCC cells to erastin-induced ferroptotic cell death, strongly suggesting that EZH2 accounts for resistance to ferroptosis. Mechanistically, EZH2 increases H3K27me3 methylation near PUFA gene promoters, leading to suppression of PUFA gene expression and subsequently low cellular PUFA level. Most interestingly, treatment of EZH2i significantly sensitized HCC cells with high EZH2 expression to erastin-induced ferroptosis, suggesting potential therapeutic opportunity for treatment of HCC patients with high EZH2 expression. Conclusion: EZH2 is a novel suppressor of ferroptosis by negatively regulating lipid metabolism. Thus, our study provides scientific evidence for developing a novel therapeutic strategy for treatment of HCC patients with co-treatment of ferroptosis inducers and EZH2 inhibitors. Citation Format: Bo Hwa Sohn, Sung Hwan Lee, Yun Seong Jeong, Ju-Seog Lee. Clinical implication of EZH2 inhibitors in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6139.

Abstract 1387: Novel thienopyrimidine-hydrazinyl analog, TPH104m inhibits mitochondrial respiration and induces caspase-independent cell death in triple-negative breast cancer cells

Abstract A triple negative breast cancer (TNBC) is an aggressive and difficult-to-treat breast cancer subtype. Neoadjuvant chemotherapy using apoptosis-inducing taxanes and/or anthracyclines has been shown to produce early therapeutic responses. Unfortunately, drug resistance often results from mutations in apoptotic pathways, which can lead to metastasis and poor prognosis. There are emerging studies suggesting that TNBC tumors display altered mitochondrial dynamics and have overexpressed dynamin related protein 1 (Drp1), which drives mitochondrial fission. Drp1 deregulation also influences metabolic changes and mitochondrial energetics, which support TNBC tumor growth. Therefore, bypassing apoptosis signaling cascade, suppressing Drp1 and reversing aberrant mitochondrial dynamics may be an effective therapy for TNBC. We report here for the first time the identification of novel thienopyrimidine-hydrazinyl analog of parent TPH104, namely, TPH104m, which inhibits Drp1 phosphorylation and induces a non-apoptotic TNBC cell death. TPH104m significantly inhibited TNBC proliferation at nanomolar concentrations, and was more selective for TNBC than normal human mammary epithelial cells. TPH104m induced a unique type of non-apoptotic cell death, where cells swelled without shrinkage, nuclear fragmentation or apoptotic bleb formation typical of apoptosis. Moreover, TPH104m did not induce the cleavage of initator (caspase-8, -9) and executioner caspases (caspase-3, -7), and zVAD.fmk, a pan-caspase inhibitor, did not rescue TNBC cell death when incubated with TPH104m. Furthermore, TPH104m did not significantly increase reactive oxygen species (ROS) production in BT-20 cells compared to Paclitaxel treated cells. Although mitochondrial membrane potential (MMP) was significantly reduced, cytochrome C release was not increased, but instead decreased, explaining why MMP loss did not lead to apoptosis. TPH104m remarkably downregulated the phosphorylated and total forms of Drp1 protein in TNBC cells. A docking-based reverse screening approach and Surface Plasmon Resonance (SPR) data indicated that TPH104m binds to Drp1 more strongly than Mdivi-1, a weak non-specific Drp1 inhibitor. A complete and partial Drp1 KO cell line was created in SUM-159 TNBC cells to investigate the role of Drp1 in TPH104m-induced non-apoptotic cell death. Genetically deleting Drp1 from TNBC cells reduced TPH104m's cytotoxic potential suggesting Drp1's role in TPH104m's anticancer mechanism. Moreover, mito-stress assay showed that TPH104m severely impaired oxygen consumption rate, resulting in decreased ATP production and inhibition of mitochondrial respiration. Development of alternative treatments for TNBC will be facilitated by a deeper understanding of mitochondrial role in non-apoptotic cell death. Citation Format: Saloni Malla, David Terrero, Sushma Karki, Mariam Sami Abou-Dahech, Shikha Kumari, Amit K. Tiwari. Novel thienopyrimidine-hydrazinyl analog, TPH104m inhibits mitochondrial respiration and induces caspase-independent cell death in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1387.

Dihydroorotate dehydrogenase regulates ferroptosis in neurons after spinal cord injury via the P53-ALOX15 signaling pathway.

Spinal cord injury (SCI) is a highly disabling condition in spinal surgery that leads to neuronal damage and secondary inflammation. Ferroptosis is a non-apoptotic type of cell death that has only recently been identified, which is marked primarily by iron-dependent and lipid-derived reactive oxygen species accumulation, and accompanied by morphological modifications such as mitochondrial atrophy and increase in membrane density. Dihydroorotate dehydrogenase (DHODH) is a powerful inhibitor of ferroptosis and has been demonstrated to inhibit cellular ferroptosis in tumor cells, but whether it can inhibit neuronal injury following spinal cord injury remains ambiguous. In this study, the effect of DHODH on neuronal ferroptosis was observed in vivo and in vitro using a rat spinal cord injury model and erastin-induced PC12 cells, respectively. A combination of molecular and histological approaches was performed to assess ferroptosis and explore the possible mechanisms in vivo and in vitro. First, we confirmed the existence of neuronal ferroptosis after spinal cord injury and that DHODH attenuates neuronal damage after spinal cord injury. Second, we showed molecular evidence that DHODH inhibits the activation of ferroptosis-related molecules and reduces lipid peroxide production and mitochondrial damage, thereby reducing neuronal ferroptosis. Further analysis suggests that P53/ALOX15 may be one of the mechanisms regulated by DHODH. Importantly, we determined that DHODH inhibits ALOX15 expression by inhibiting P53. Our findings reveal a novel function for DHODH in neuronal ferroptosis after spinal cord injury, suggesting a unique therapeutic target to alleviate the disease process of spinal cord injury.

A novel methuosis inducer DZ-514 possesses antitumor activity via activation of ROS-MKK4-p38 axis in triple negative breast cancer

Triple-negative breast cancer (TNBC) is one of the most malignant tumors with poor prognosis. Methuosis is a new type of nonapoptotic cell death characterized by the accumulation of cytoplasmic vacuoles. In this study, we synthesized and screened a series of N-phenyl-4-pyrimidinediamine derivatives in TNBC cells, finding that DZ-514 was the best compound with high toxicity independent of the inhibition of BCL6. DZ-514 decreased cell viability, inhibited cell cycle progression, and induced caspase-independent cell death in TNBC cells. Interestingly, DZ-514 induced cytoplasm vacuolation, which could be blocked by Baf A1, the V-ATPase inhibitor. Furthermore, we found that DZ-514-induced vacuoles were derived from macropinosomes rather than autophagosomes. Most importantly, methuosis induced by DZ-514 was partially mediated by activating the ROS-MKK4-p38 axis. Finally, we demonstrated that DZ-514 significantly inhibited tumor growth in an HCC1806 xenograft mouse model. These findings revealed that the novel methuosis inducer DZ-514 could be developed for TNBC treatment.