Cell Death & Disease最新文献

Metastatic gastric cancer (GC) has a poor prognosis. Recent research demonstrated the aberrant expression of nuclear receptor HNF4α and the regulatory roles of its isoforms during the processes of tumorigenesis and development. However, the expression patterns of HNF4α and its potential as a therapeutic target in metastatic GC remain elusive. In this study, we unveiled that P2 promoter-driven HNF4α (P2-HNF4α) was highly expressed in distant metastasis of GC, playing a pivotal role in fostering the migration and metastasis of GC cells both in vitro and in vivo. The transactivational activity was essential for HNF4α to promote GC cell migration. An integrative analysis of transcriptome and metabolome implied the involvement of the glycolytic pathway in the promotion of GC cell migration by P2-HNF4α. We further found that P2-HNF4α directly bound to the enhancer of the HKDC1 gene and upregulated its expression, thereby orchestrating a metabolic rewiring conducive to promoting GC migration and metastasis. Mycophenolic acid, an active metabolite of the FDA-approved drug mycophenolate mofetil, demonstrated the ability to suppress HKDC1 expression and GC migration and metastasis in vitro and in vivo through antagonizing HNF4α. Therefore, this study sheds light on the HNF4α-HKDC1 axis as a key player in GC metastasis, providing a promising targeted therapeutic strategy for metastatic GC.

Conventionally, KDM5C functions as a specific demethylase that targets histone H3 lysine 4 dimethyl and trimethyl modifications, crucial for gene expression. However, the role of KDM5C in multiple myeloma (MM) progression and bortezomib (BTZ) resistance has remained elusive. In this study, we found noncanonical functions of KDM5C in MM. Specifically, KDM5C binds to CBP and MYC, conferring BTZ resistance in MM through a demethylase-independent mechanism. Our investigations revealed that KDM5C is markedly upregulated in BTZ-resistant MM patients as well as those with relapsed MM. Significantly, the expression level of KDM5C exhibits an inverse correlation with the overall survival of MM patients. Moreover, KDM5C is indispensable for MM cell proliferation. Depletion of KDM5C augmented the sensitivity of MM cells to BTZ treatment both in vitro and in vivo. We found that KDM5C forms a novel complex with CBP and MYC via its PHD2 domain. This complex formation triggers lysine 27 acetylation in histone H3 (H3K27ac) and subsequent enrichment of H3K27ac on the PERK promoter. As a result, PERK transcription is activated, and Nrf2 phosphorylation is promoted, bolstering the unfolded protein response within the endoplasmic reticulum of MM cells. In contrast, the methylation status of histone H3 lysine 4 (H3K4me1/3) on the PERK promoter remains unaltered, regardless of the complex state. Taken together, the findings of this study underscore the key role of KDM5C as a driving force behind MM progression and BTZ resistance, indicating that KDM5C represents a novel and promising therapeutic target for the treatment of BTZ-resistant MM.

COVID-19 patients readily present with severe epithelial damage, such as tissue ulceration and erosion, along with disrupted tissue repair, in multiple organs. The mucous membranes of the lung alveoli [1, 2], gastrointestinal tract [3, 4], nasal [5] and oral cavity [6, 7] are the primary targets of the SARS-CoV-2 virus. The infected epithelium triggers a dysregulated immune response that further damages tissues and organs [8-10]. Increasing evidence suggests that the SARS-CoV-2 virus can cause direct damage to epithelial cells and fibroblasts [11-13]. Here, we report that the mucosa epithelia of COVID-19 patients can undergo cellular dedifferentiation before any pathological features are observed. SARS-CoV-2 nonspike structural proteins, particularly the Envelope protein, can rapidly induce epithelial cell dedifferentiation, micronuclei formation, cell cycle arrest at the G1 phase and apoptosis. The protein can also severely affect the progenitor cell stratification program. Mechanistically, we identified a unique molecule, calponin 2 (CNN2), as a downstream effector of nonspike structural proteins. Moreover, CNN2 levels were elevated in the epithelia of COVID-19 patients. Downregulating CNN2 could inhibit epithelial cell apoptosis and promote cell differentiation. CNN2 expression is negatively regulated by GLIS2, a transcription factor associated with the disruption of ciliary dynamics in epithelial cells. Therefore, we propose that SARS-CoV-2 damages mucosal epithelium integrity via a novel "double hijack" mechanism: inducing dedifferentiation and disrupting stratification and suggest a new therapeutic target: CNN2 for COVID-19 treatment.

Emerging evidence demonstrates the important role of ferroptosis, a novel regulated cell death, in the initiation and progression of acute kidney injury (AKI). However, the activation mechanism of ferroptosis in AKI has not been fully revealed. The pivotal function of interferon inducible protein 16 (IFI16) in DNA damage response (DDR) as DNA sensor and regulator of cell death pathways encouraged us to examine its role in ferroptosis of renal tubular epithelial cells (TECs) in AKI. Here we report that the levels of IFI16 and its mouse ortholog p204 were elevated in the kidney of patients with acute tubular necrosis (ATN) and in TECs of mice with renal ischemia/reperfusion (I/R)-induced AKI (I/R-AKI). Under I/R conditions, tubule-specific p204 deficiency in mice and IFI16 knockout in HK-2 cells significantly ameliorated TEC ferroptosis. Mechanistically, IFI16 binds to poly(ADP-ribose) polymerase 1 (PARP-1) and enhances protein Poly ADP-ribosylation (PARylation), which in turn potentiates the ataxia-telangiectasia mutated (ATM)-p53 signaling contributing to lipid peroxidation and ferrous ion accumulation in TECs. In addition, IFI16-amplified DDR was dependent on its HIN and PYRIN domains. Thus, our findings provide a better understanding of a critical pathogenic axis linking DNA damage to ferroptosis and suggest that targeting IFI16 may be an innovative therapeutic strategy for treating patients with AKI.

Sphingosine-1-phosphate (S1P) has been implicated in promoting breast cancer progression, but its role in fostering an immunosuppressive microenvironment remains largely unexplored. In our study, co-culturing CD8 T cells with S1P-treated MCF7 cells significantly reduced CD8 T cell proliferation, an effect reversed by inhibiting exosome biogenesis. S1P treatment enhanced exosome release from breast cancer cells, with increased levels of TGFBR2 detected on the exosome surface. These S1P-induced exosomes promoted CD8 T cell exhaustion. Silencing TGFBR2 in cancer cells or treating with anti-TGFBR2 antibodies mitigated CD8 T cell exhaustion thereby highlighting the pivotal role of TGFBR2. Further investigation revealed that S1P drives the production of TGFBR2-loaded exosomes by activating the S1P1 receptor and engaging the AKT-Rab27a axis to facilitate exosome release. Additionally, S1P upregulates TGFBR2 expression and stability through the S1P1-LEF1 and S1P1-CREB1-USP8 pathways respectively, thereby contributing to immune suppression. In vivo administration of exosomes derived from S1P-treated murine breast cancer cells in a breast cancer allograft model markedly promoted tumor growth and heightened CD8 T cell exhaustion, whereas exosomes from TGFBR2-silenced, S1P-treated cells exerted the reverse effect, underscoring the pivotal role of the S1P-TGFBR2 axis in modulating the tumor microenvironment. These findings suggest that targeting the S1P-TGFBR2 pathway could enhance antitumor immunity in breast cancer.

Although phosphoinositide 3-kinase-δ (PI3Kδ) inhibition demonstrates efficacy in relapsed/refractory follicular lymphoma (FL), its clinical benefit is often limited by adaptive resistance, underscoring the need for rational combination strategies. Here, we show that combining the PI3Kδ inhibitor linperlisib with the pan-peroxisome proliferator-activated receptor (PPAR) agonist chiglitazar, an agent that reprograms tumor metabolism, delivers robust antitumor activity across FL models, including cell-derived and patient-derived xenografts, with a favorable tolerability profile. The combined regimen promotes G1/S arrest and apoptosis, exerting complementary metabolic and signaling effects through glycolysis suppression, activation of PPARα-driven programs, and consequent reactivation of the transcription factor forkhead box protein O1 (FoxO1), which is repressed by PI3K/AKT signaling. Genetic depletion of FoxO1 attenuates treatment responses, identifying FoxO1 activity as both a pharmacodynamic biomarker and a potential predictor of therapeutic benefit. Compared with monotherapy, the combination consistently achieves superior tumor control in vivo without overt toxicity, supporting its clinical translation potential. Collectively, these data provide a mechanistic rationale for dual targeting of PI3Kδ and PPARα in FL and advocate for clinical evaluation of this combination with FoxO1 as a pharmacodynamic biomarker.

Aging is a major contributor to the escalating prevalence of heart failure (HF). Ferroptosis has been implicated in age-related disorders and cardiovascular diseases. The role of ferroptosis in age-related HF remains unclear. Here, we show that aged rats exhibit impaired cardiac function accompanied by hallmark features of ferroptosis, including reduced glutathione peroxidase 4 (GPX4) expression and excessive lipid peroxidation. Consistently, cardiomyocyte-specific GPX4 knockout mice develop exacerbated cardiac ferroptosis and pronounced cardiac dysfunction. Iron overload further aggravates ferroptotic injury and cardiac dysfunction in aged rats, whereas pharmacological inhibition of ferroptosis markedly alleviates these effects. Conversely, cardiomyocyte-specific overexpression of GPX4 via rAAV9 attenuates ferroptosis and preserves cardiac function in D-galactose-induced aging mice. Proteomic analysis identifies hydroxyacyl-CoA dehydrogenase subunit A (HADHA) as a key protein markedly downregulated in aging hearts, particularly under iron overload. Mechanistically, HADHA deficiency induces mitochondrial dysfunction and excessive reactive oxygen species production, leading to glutathione depletion, GPX4 suppression, and subsequent ferroptosis. Accordingly, cardiomyocyte-specific knockdown of HADHA in young mice recapitulates ferroptosis-associated cardiac remodeling, which is reversed by ferrostatin-1 treatment. Furthermore, we identify SIRT1 (sirtuin 1) as an upstream regulator of HADHA during cardiac aging. Reduced SIRT1 expression in aging hearts suppresses HADHA transcription through inhibition of GATA4. Importantly, both cardiomyocyte-specific SIRT1 overexpression via rAAV9 in D-galactose-induced aging mice and pharmacological SIRT1 activation by resveratrol in aging rats restore HADHA expression, suppress ferroptosis, and protect against HF. Collectively, these findings establish ferroptosis as a critical contributor to age-related HF and identify the SIRT1-GATA4-HADHA axis as a potential therapeutic target.

Retinoblastoma (RB) is the most common primary intraocular malignancy in children, and its extraocular extension is closely linked to poor prognosis. However, the molecular drivers underlying local invasion remain incompletely defined. Here, we identify β‑1,4‑galactosyltransferase III (B4GALT3) as a glycosyltransferase selectively upregulated in highly proliferative MKI67⁺ RB subpopulations. B4GALT3 promotes RB cell proliferation, fibronectin adhesion, and invasion by enhancing β1-integrin glycosylation, thereby activating FAK signaling and inducing MMP2 expression to disrupt retinal epithelial barriers. Genetic modulation of B4GALT3 significantly altered both tumor burden and invasive behavior in orthotopic xenograft models. Structure-based virtual screening identified myricoside as a B4GALT3 inhibitor, which suppressed RB malignancy in vitro and in vivo. Overall, our findings uncover a B4GALT3-integrin-FAK axis as a key regulator of RB progression and highlight B4GALT3 inhibition as a promising therapeutic strategy for advanced RB.

Melanoma accounts for over 85% of all skin cancer deaths. Current therapies including drugs targeting BRAF and MEK significantly improve the prognosis of metastatic melanoma patients, yet innate or acquired resistance challenges long-term responses. We have shown previously that fatty acid beta-oxidation (FAO) is up-regulated during the acquisition of BRAF-inhibitor (BRAFi) resistance and that the FDA approved drug ranolazine, by targeting FAO attenuates the development of acquired resistance. However, how ranolazine-induced metabolic rewiring increases cell death is unclear. Here we identify ranolazine as a ferroptosis inducer in BRAFi-resistant melanoma, in which FAO serves as a ferroptosis surveillance mechanism. Accordingly, in progressed tumours of BRAFi treated patients up-regulation of FAO regulators correlates with increased expression of ferroptosis markers. BRAFi resistant cells are heavily poised for execution of ferroptosis; they display reduced glutathione levels, higher levels of long-chain polyunsaturated fatty acid (PUFA) membrane-incorporation, and increased membrane-resident phospholipid oxidation, all of which is amplified by ranolazine. Counteracting ranolazine action is MBOAT1/2 mediated phospholipid remodelling, which initiates reduced PUFA membrane-incorporation as ferroptosis surveillance mechanism. We show that the androgen receptor (AR), which is a determinant of BRAFi resistance, controls MBOAT1/2 expression, thereby contributing to ferroptosis resistance. In BRAFi resistant tumours and cell lines, we confirm AR upregulation predominantly in the MITF^low/AXL^high undifferentiated/neural-crest like state, but it also occurs in the MITF^high/AXL^low differentiated melanocytic state. The AR antagonist enzalutamide sensitises AR expressing melanoma cells to RSL3 and erastin independent of phenotype state, but in FAO^high BRAFi relapsed tumours AR up-regulation correlates with the undifferentiated/neural-crest like (UD/NC) state, and enzalutamide synergises with ranolazine in ferroptosis-induction in UD/NC cells. Thus, therapeutically combining ranolazine with the AR inhibitor enzalutamide to induce ferroptosis can circumvent dedifferentiation related BRAFi resistance and could increase therapeutic activity and long-term efficacy.

Synaptic deficit has emerged as a key early hallmark for neurodegeneration in the visual pathway. The molecular pathway connecting local synaptic deficit with global cell dysfunction and death remains unclear. We have previously shown that α2δ4, an auxiliary subunit of the voltage-gated calcium channel, is targeted to photoreceptor synapses and required for their formation and function. Notably, α2δ4 mutations have been identified in patients with retinal dystrophy. However, how loss of synaptic α2δ4 leads to overall photoreceptor degeneration remains unknown. Here, we showed that α2δ4 loss in mice leads to a late onset photoreceptor degeneration around 7 months. Consistent with clinical observation, the progression of degeneration is minimal until 17 months, as supported by ERG, OCT imaging and histology. We found that Cav1.4 KO mice, where the calcium channel is missing, display an earlier degeneration onset than α2δ4 KO mice, where calcium channel is partially preserved. Proteomic studies revealed that tricarboxylic acid (TCA) cycle is significantly downregulated in the young α2δ4 KO retinas prior to degeneration. Transmission electron microscopy study demonstrated significant reduction in mitochondrial size and number in photoreceptor synaptic terminals, but not in the inner segment (IS), of the young α2δ4 KO retinas. Consistently, immunohistochemistry (IHC) studies showed significant reduction of mitochondrial proteins in the outer plexiform layer (OPL). IHC studies on ER and mitochondrial proteins revealed that ryanodine receptor (RyR2) and mitochondrial calcium uniporter (MCU) are downregulated in the OPL, but not in the IS. Together, our results propose a model where α2δ4 dysfunction impairs Cav1.4 channel activity, leading to disrupted calcium crosstalk among the plasma membrane, ER, and mitochondria, as well as mitochondrial damage and metabolic deficits. Importantly, our study underscores the critical role of synaptic calcium homeostasis and mitochondrial integrity in connecting the early stages of synaptic dysfunction with the later stages of cell degeneration.