Cell Death & Disease最新文献

Ionising radiation causes the introduction of DNA damage, more specifically double strand breaks (DSBs) and complex DNA damage (CDD), that induces cancer cell death leading to the therapeutic effect. To combat this, cells activate arrest at the G₂/M checkpoint to allow for effective DNA damage repair, coordinated by the Chk1 and Wee1 protein kinases. Therefore, Chk1 and Wee1 are considered promising therapeutic targets to enhance the effectiveness of radiotherapy in cancer cell killing. Here, we have analysed the response of head and neck squamous cell carcinoma (HNSCC) cell lines, spheroids and patient-derived organoids to X-rays and proton beam therapy (PBT) in the presence of either a Chk1 (MK-8776) or a Wee1 (MK-1775) inhibitor. We demonstrate that inhibitors of Chk1 or Wee1 can significantly enhance the radiosensitivity of both 2D and 3D models of HNSCC to X-rays and PBT (performed at both low and high ionisation densities), and that this effect is caused through abrogation of the G₂/M checkpoint causing the persistence of DSBs. Our results therefore suggest that targeting Chk1 and Wee1 kinases in combination with X-rays and PBT could represent a promising therapeutic avenue to enhance the clinical efficacy of HNSCC treatment.

While apoptotic cell death is known to be central to the pathogenesis of radiation-induced liver injury (RILI), the mechanistic basis for this apoptotic activity remains poorly understood. N⁶-methyladenosine (m⁶A) modifications are the most common form of reversible methylation observed on lncRNAs in eukaryotic cells, with their presence leading to pronounced changes in the activity of a range of biological processes. The degree to which m⁶A modification plays a role in the induction of apoptotic cell death in response to ionizing radiation (IR) in the context of RILI remains to be established. Here, IR-induced apoptosis was found to significantly decrease the levels of m⁶A present, with a pronounced decrease in the expression of methyltransferase-like 3 (METTL3) at 2 d post radiation in vitro. From a mechanistic perspective, a methylated RNA immunoprecipitation assay found that lncRNA MEG3 was a major METTL3 target. The expression of MEG3 was upregulated via METTL3-mediated m⁶A in a process that was dependent on YTHDC1, ultimately reversing the miR-20b-mediated inhibition of BNIP2 expression. Together, these findings demonstrate that the responsivity of METTL3 activity to IR plays a role in IR-induced apoptotic cell death, leading to the reverse of miR-20b-mediated BNIP2 inhibition through the YTHDC1-dependent m⁶A modification of MEG3, suggesting that this process may play a central role in RILI incidence.

Cancer-associated fibroblasts (CAFs) play a key role in oxaliplatin resistance in pancreatic ductal adenocarcinoma (PDAC). However, the potential mechanisms by which CAFs promote chemotherapy resistance have not yet been explored. In this study, we found that circABCC4 (hsa_circ_0030582) was positively correlated with poor platinum-chemotherapeutic response and a shorter progression-free survival (PFS) time in late-stage PDAC patients. CircABCC4 enhanced the ability of CAFs to induce oxaliplatin resistance in pancreatic cancer cells through glycolysis reprogramming. Mechanistically, circABCC4 enhanced the interaction between PKM2 and KPNA2 to promote PKM2 nuclear translocation in CAFs, leading to the transcription of glycolysis-related genes. The glycolytic reprogramming of CAFs promoted the secretion of IL-8, which in turn enhanced DNA damage repair in pancreatic cancer. Blocking PKM2 nuclear translocation abolished circABCC4-driven oxaliplatin resistance of pancreatic cancer in vivo. Collectively, our study reveals a circRNA-mediated glycolysis reprogramming of CAFs to induce oxaliplatin resistance and highlights circABCC4 as a potential therapeutic target.

Axitinib resistance remains a serious challenge in the treatment of advanced renal cell carcinoma (RCC), and the underlying mechanisms are not fully understood. Here, we constructed an in vivo axitinib-resistant RCC model and identified the long non-coding RNA STX17-DT as a driver of therapy resistance in RCC. The expression of STX17-DT was significantly elevated in axitinib-resistant RCC cells and correlated with poorer prognosis in RCC patients. Elevated levels of STX17-DT contributed to the development of resistance to axitinib both in vitro and in vivo. Mechanistically, STX17-DT modulated the stability of IFI6 mRNA by recruiting and binding to hnRNPA1, leading to decreased accumulation of mitochondrial reactive oxygen species (ROS) and attenuated ferroptosis. Meanwhile, STX17-DT was packaged into extracellular vesicles through hnRNPA1, thus transmitting axitinib resistance to other cells. Compared with axitinib monotherapy, combined treatment of axitinib and STX17-DT-targeted in vivo siRNA demonstrated enhanced therapeutic efficacy. These findings indicate a novel molecular mechanism of axitinib resistance in RCC and suggest that STX17-DT may serve as a prognostic indicator and potential therapeutic target to overcome resistance to targeted therapy.

Cellular glutathione (GSH) in lung cancer cells represents the most abundant antioxidant. GSH production is regulated not only by upregulated cystine/glutamate exchanger (xCT) but also by the involvement of glutamate transporters, specifically excitatory amino acid transporter 3 (EAAT3). Our prior research established that the uptake of glutamate via EAAT3 plays a pivotal role in driving cystine uptake through xCT, contributing to GSH biosynthesis during lung tumorigenesis. Nevertheless, the underlying mechanism governing the upregulation of EAAT3 remains enigmatic. In this study, we conducted a comprehensive reanalysis of publicly available data and employed the Gprc5a^-/-/SR-IκB mouse model alongside in vitro cell experiments to elucidate the correlations between NF-κB and EAAT3 in lung cancer. We observed that EAAT3 knockdown, similar to NF-κB inhibition, led to the accumulation of reactive oxygen species (ROS) and increased sensitivity to ferroptosis induction by RAS-selective lethal 3 (RSL3). Mechanistic insights were obtained through chromatin immunoprecipitation and luciferase reporter assays, revealing that NF-κB induces EAAT3 expression via two putative cis-elements within its promoter. Furthermore, our investigation unveiled the upregulation of EAAT3 in a subset of clinical non-small cell lung cancer (NSCLC) tissues, exhibiting a positive correlation with the P65 protein. In addition, the inflammatory factor of smoking was found to augment EAAT3 expression in both human and murine experimental models. These findings collectively emphasize the pivotal role of the NF-κB/EAAT3 axis in managing antioxidant stress and influencing lung cancer development. Moreover, this research offers insights into the potential for a combined ferroptosis therapy strategy in lung cancer treatment.

Sepsis can trigger systemic inflammation and lead to detrimental effects on several organs, with particular emphasis on the lungs. In sepsis-associated lung injury, macrophages assume a pivotal role, as their overactivation could facilitate the secretion of inflammatory factors and the imbalance of polarization. Hepatocyte nuclear factor 4 alpha (HNF4A) has been reported its potential involvement in the regulation of inflammatory response and macrophage polarization. This study discusses the role and mechanism of HNF4A in sepsis-induced lung damage. HNF4A exhibits a decrease in expression by analyzing the differentially expressed genes in the lungs of septic mice from the Gene Expression Omnibus dataset GSE15379. Then, we established a mouse sepsis model through a cecal ligation and puncture method and observed that the expression of HNF4A was reduced in both lung tissues and alveolar macrophages. To evaluate the function of HNF4A, we overexpressed HNF4A mediated by adenovirus vectors, which were injected into mice. We found that HNF4A overexpression resulted in a higher survival rate in septic mice and an amelioration of pulmonary damage. Meanwhile, HNF4A overexpression mitigated the infiltration of inflammatory cells and impeded the M1 polarization but facilitated the M2 polarization of macrophages in the lung tissues or the alveolar lavage fluid. In vitro, we treated bone marrow-derived macrophages with interleukin-4. Consistent results were obtained that HNF4A overexpression promoted the M2 polarization of macrophages. Mechanistically, we found that HNF4A transcriptionally regulate the expression of nuclear receptor coactivator 2 (NCOA2) through binding to its promoter region. NCOA2 interacted with glucocorticoid receptor (GR). Stabilin 1 (STAB1) was selected as a possible target by transcriptome sequencing analysis. Functional experiments confirmed STAB1 as a downstream target of the HNF4A/NCOA2/GR axis. Overall, this research investigated the potential impact of HNF4A on pulmonary injury in sepsis. It is suggested that one of the regulatory mechanisms involved in this association may be the NCOR2/GR/STAB1 axis.

Vascular endothelial cells are the predominant cell type in the cardiovascular system, and their dysfunction and death following hypoxic injury contribute to vascular lesions, playing an essential role in cardiovascular disease. Despite its importance, the mechanisms underlying vascular endothelial cell injury under hypoxia and potential therapeutic interventions remain poorly understood. Here, we constructed both an in vivo hypoxia model in C57BL/6 mice and an in vitro hypoxia model in HUVEC cells. Our findings demonstrated that hypoxia induces necroptosis in vascular endothelial cells and exacerbates inflammatory injury in vivo and in vitro, as evidenced by immunofluorescence and western blot. We identified FADD as a critical regulator of hypoxia-mediated necroptosis, with FADD knockdown significantly reversing hypoxia-induced necroptosis. Mechanistically, hypoxia affected protein conformation through SUMOylation of FADD and competitively inhibited its ubiquitination, leading to an increase in protein half-life and protein level of FADD. Furthermore, SUMOylation increased the interaction between FADD and RIPK1 and induced the formation of the FADD-RIPK1-RIPK3 complex, thereby promoting necroptosis in vascular endothelial cells. The SUMOylation inhibitor ginkgolic acid (GA) notably reduced hypoxia-induced vascular endothelial injury and inflammatory responses in male mice. Taken together, our research has uncovered a new process by which SUMOylation of FADD regulates hypoxia-induced necroptosis in endothelial cells, providing potential therapeutic targets for hypoxia-related cardiovascular diseases.

Germline mutations of the deubiquitinase BRCA1-associated protein 1 (BAP1) lead to the "BAP1 cancer syndrome" characterized by development of cancers. However, the role of BAP1 in hepatocellular carcinoma (HCC) is unclear. We found that BAP1 was upregulated at mRNA level in human HCCs and significantly correlated with a more aggressive tumour behaviour. Intriguingly, we observed cytoplasmic but no or minimal nuclear BAP1 in human HCC samples by immunohistochemistry. We observed that, while BAP1 protein was found mainly in the cytoplasm and less in the nuclei of HCC cell lines, BAP1 expression was predominantly nuclear in HepG2 cells, by cell fractionation and immunofluorescence analyses. Functionally, in the orthotopic liver injection mouse model, silencing the BAP1 predominant nuclear expression of HepG2 cells promoted intrahepatic tumor metastasis, with more frequent tumor microsatellite formation and venous invasion. With transcriptomic profiling, we identified RHOJ amongst the downregulated targets in HepG2 cells upon BAP1 knockdown. Subsequent overexpression of RHOJ suppressed cell migration in HCC cells, suggesting that BAP1 might upregulate RHOJ resulting in reduced cell migratory ability of HCC cells. Furthermore, we identified two transcription factors, CTCF and NRF1, which activated BAP1 transcription by binding to BAP1 promoter region. On the other hand, we uncovered that O-linked N-acetylglucosamine (GlcNAc) transferase (OGT) physically bound to BAP1 in the nucleus, resulting in diminished stability of the nuclear BAP1. Intriguingly, OGT transcription was upregulated and was also under the control of CTCF and NRF1 in human HCC, acting as a negative regulator of BAP1. To summarize, this study uncovered the underlying mechanisms of the regulation of BAP1 and that loss of the nuclear localization of BAP1 protein contributed to enhanced cell migration in vitro and more aggressive tumor behavior in human HCCs.

We previously identified CLDN6 as a pivotal tumor suppressor in breast cancer and unexpectedly discovered that overexpression of CLDN6 resulted in characteristic ultrastructural alterations of ferroptosis. However, the exact mechanism by which CLDN6 triggers ferroptosis is still elusive in breast cancer. Our study showed that CLDN6 was associated with ferroptosis in breast cancer patients. The integration of CLDN6 and ferroptosis demonstrated remarkable predictive prognostic performance. We observed that CLDN6 triggers NRF2-mediated ferroptosis in vitro and in vivo. Mechanistically, CLDN6 enhanced nuclear export of NRF2 by regulating the PBK-dependent AKT/GSK3β/FYN axis. Further CLDN6 recruited PBK to the cell membrane through the endosomal pathway and bound with the DLG1/PBK complex, thereby promoted the degradation of PBK by the UPS. This study elucidates the previously unrecognized mechanism of CLDN6 triggering NRF2-mediated ferroptosis through recruiting DLG1/PBK complex. This study provides a reliable biomarker for predicting prognosis and is anticipated to guide the selection of therapies targeting ferroptosis in breast cancer.

Acute kidney injury (AKI) is in rapid prevalence nowadays. Of note, the underlying mechanisms have not been clarified. Several reports showed a cluster of differentiation-44 (CD44), a cell-surface glycoprotein, might be involved in AKI. However, its role in AKI has not been clearly clarified. Herein, we found CD44 increased in renal tubules in AKI mice. Gene ablation of CD44 improved mitochondrial biogenesis and fatty acid oxidation (FAO) function, further protecting against tubular cell death and kidney injury. Conversely, ectopic CD44 impaired mitochondrial homeostasis and exacerbated tubular cell apoptosis to aggravate AKI progression. From transcriptome sequencing, we found that CD44 induces mitogen-activated protein kinase (MAPK) and NF-κB p65 signaling. Lipidomics also showed that CD44 interfered with multiple aspects of lipid metabolism. We deeply investigated NF-κB p65 inhibited the transcription of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), resulting in mitochondrial dysfunction and cell apoptosis. CD44 also facilitated iron intake to assist cell ferroptosis. Hence, our study provided a new mechanism for AKI, and demonstrated that targeted inhibition on CD44 could be a promising therapeutic strategy to resist AKI.