1G6-D7 Inhibits Homologous Recombination Repair by Targeting Extracellular HSP90α to Promote Apoptosis in Non-Small Cell Lung Cancer.

Despite recent advances in treatment, non-small cell lung cancer (NSCLC) continues to have a high mortality rate. Currently, NSCLC pathogenesis requires further investigation, and therapeutic drugs are still under development. Homologous recombination repair (HRR) repairs severe DNA double-strand breaks. Homologous recombination repair deficiency (HRD) occurs when HRR is impaired and causes irreparable double-strand DNA damage, leading to genomic instability and increasing the risk of cancer development. Poly(ADP-ribose) polymerase (PARP) inhibitors can effectively treat HRD-positive tumors. Extracellular heat shock protein 90α (eHSP90α) is highly expressed in hypoxic environments and inhibits apoptosis, thereby increasing cellular tolerance. Here, we investigated the relationship between eHSP90α and HRR in NSCLC. DNA damage models were established in NSCLC cell lines (A549 and H1299). The activation of DNA damage and HRR markers, apoptosis, proliferation, and migration were investigated. In vivo tumor models were established using BALB/c nude mice and A549 cells. We found that human recombinant HSP90α stimulation further activated HRR and reduced DNA damage extent; however, eHSP90α monoclonal antibody, 1G6-D7, effectively inhibited HRR. HRR inhibition and increased apoptosis were observed after LRP1 knockdown; this effect could not be reversed with hrHSP90α addition. The combined use of 1G6-D7 and olaparib caused significant apoptosis and HRR inhibition in vitro and demonstrated promising anti-tumor effects in vivo. Extracellular HSP90α may be involved in HRR in NSCLC through LRP1. The combined use of 1G6-D7 and PARP inhibitors may exert anti-tumor effects by inhibiting DNA repair and further inducing apoptosis of NSCLC cells.

Human epididymis protein 4, a novel potential biomarker for diagnostic and prognosis monitoring of lung cancer.

OBJECTIVE: This study aimed to explore the application value of human epididymis protein 4 (HE4) in diagnosing and monitoring the prognosis of lung cancer. METHODS: First, TCGA (The Cancer Genome Atlas) databases were used to analyze whey-acidic-protein 4-disulfide bond core domain 2 (WFDC2) gene expression levels in lung cancer tissues. Then, a total of 160 individuals were enrolled, categorized into three groups: the lung cancer group (n = 80), the benign lesions group (n = 40), and the healthy controls group (n = 40). Serum HE4 levels and other biomarkers were quantified using an electro-chemiluminescent immunoassay. Additionally, the expression of HE4 in tissues was analyzed through immunohistochemistry (IHC). In vitro cultures of human airway epithelial (human bronchial epithelial [HBE]) cells and various lung cancer cell lines (SPC/PC9/A594/H520) were utilized to detect HE4 levels via western blot (WB). RESULTS: Analysis of the TCGA and UALCAN (The University of Alabama at Birmingham Cancer Data Analysis Portal) databases showed that WFDC2 gene expression levels were upregulated in lung cancer tissues (p < 0.01). Compared with the control group and the benign group, HE4 was significantly higher in the serum of patients with lung cancer (p < 0.001). Receiver operating characteristic (ROC) analysis confirmed that HE4 had better diagnostic efficacy than classical markers in the differential diagnosis of lung cancer and benign lesions and had the highest diagnostic value in lung adenocarcinoma (area under the ROC curve [AUC] = 0.826). HE4 increased in early lung cancer and positively correlated with poor prognosis (p < 0.001). Moreover, the results of WB and IHC revealed that the expression of HE4 was increased in lung cancer cells (SPC/A549/H520) and lung cancer tissues but decreased in PC9 cells with a lack of exon EGFR19 (p < 0.05). CONCLUSION: Serum HE4 emerges as a promising novel biomarker for the diagnosis and prognosis assessment of lung cancer.

Polystyrene microplastics induce pulmonary fibrosis by promoting alveolar epithelial cell ferroptosis through cGAS/STING signaling.

Polystyrene microplastics (PS-MPs) are new types of environmental pollutant that have garnered significant attention in recent years since they were found to cause damage to the human respiratory system when they are inhaled. The pulmonary fibrosis is one of the serious consequences of PS-MPs inhalation. However, the impact and underlying mechanisms of PS-MPs on pulmonary fibrosis are not clear. In this study, we studied the potential lung toxicity and PS-MPs-developed pulmonary fibrosis by long-term intranasal inhalation of PS-MPs. The results showed that after exposing to the PS-MPs, the lungs of model mouse had different levels of damage and fibrosis. Meanwhile, exposing to the PS-MPs resulted in a markedly decrease in glutathione (GSH), an increase in malondialdehyde (MDA), and iron overload in the lung tissue of mice and alveolar epithelial cells (AECs). These findings suggested the occurrence of PS-MP-induced ferroptosis. Inhibitor of ferroptosis (Fer-1) had alleviated the PS-MPs-induced ferroptosis. Mechanically, PS-MPs triggered cell ferroptosis and promoted the development of pulmonary fibrosis via activating the cGAS/STING signaling pathway. Inhibition of cGAS/STING with G150/H151 attenuated pulmonary fibrosis after PS-MPs exposure. Together, these data provided novel mechanistic insights of PS-MPs-induced pulmonary fibrosis and a potential therapeutic paradigm.

Up-regulation of HSP90α in HDM-induced asthma causes pyroptosis of airway epithelial cells by activating the cGAS-STING-ER stress pathway.

Heat Shock protein 90 α (HSP90α), an main subtype of chaperone protein HSP90, involves important biological functions such as DNA damage repair, protein modification, innate immunity. However, the potential role of HSP90α in asthma occurrence and development is still unclear. This study aimed to elucidate the underlying mechanism of HSP90α in asthma by focusing on the cGAS-STING-Endoplasmic Reticulum stress pathway in inflammatory airway epithelial cell death (i.e., pyroptosis; inflammatory cell death). To accomplish that, we modeled allergen exposure in C57/6BL mice and bronchial epithelial cells with house dust mite. Protein technologies and immunofluorescence utilized to study the expression of HSP90α, activation of cGAS-STING pathway and pyroptosis. The effect of inhibitors on HDM-exposed mice detected by histological techniques and examination of bronchoalveolar lavage fluid. Results showed that HSP90α promotes asthma inflammation via pyroptosis and activation of the cGAS-STING-ER stress pathway. Treatment with the HSP90 inhibitor tanespimycin (17-AAG) significantly relieved airway inflammation and abrogated the effect of HSP90α on pyroptosis and cGAS-STING-ER stress in vitro and in vivo models of HDM. Further data indicated that up-regulation of HSP90α stabilized STING through interaction, which increased localization of STING on the ER. Activation of STING triggered ER stress and leaded to pyroptosis-related airway inflammation. The finding showed the potential role of pyroptosis caused by dysregulation of HSP90α on airway epithelial cells in allergic inflammation, suggested that targeting HSP90α in airway epithelial cells might prove to be a potential additional treatment strategy for asthma.

Tetrandrine alleviates pulmonary fibrosis by inhibiting alveolar epithelial cell senescence through PINK1/Parkin-mediated mitophagy.

Idiopathic pulmonary fibrosis (IPF) is a fatal and insidious interstitial lung disease. So far, there are no effective drugs for preventing the disease process. Cellular senescence plays a critical role in the development of IPF, with the senescence and insufficient mitophagy of alveolar epithelial cells being implicated in its pathogenesis. Tetrandrine is a natural alkaloid which is now produced synthetically. It was known that the tetrandrine has anti-fibrotic effects, but the efficacy and mechanisms are still not well evaluated. Here, we reveal the roles of tetrandrine on AECs senescence and the antifibrotic effects by using a bleomycin challenged mouse model of pulmonary fibrosis and a bleomycin-stimulated mouse alveolar epithelial cell line (MLE-12). We performed the ß-galactosidase staining, immunohistochemistry and fluorescence to assess senescence in MLE-12 cells. The mitophagy levels were detected by co-localization of LC3 and COVIX. Our findings indicate that tetrandrine suppressed bleomycin-induced fibroblast activation and ultimately blocked the increase of collagen deposition in mouse model lung tissue. It has significantly inhibited the bleomycin-induced senescence and senescence-associated secretory phenotype (SASP) in alveolar epithelial cells (AECs). Mechanistically, tetrandrine suppressed the decrease of mitochondrial autophagy-related protein expression to rescue the bleomycin-stimulated impaired mitophagy in MLE-12 cells. We revealed that knockdown the putative kinase 1 (PINK1) gene by a short interfering RNA (siRNA) could abolish the ability of tetrandrine and reverse the MLE-12 cells senescence, which indicated the mitophagy of MLE-12 cells is PINK1 dependent. Our data suggest the tetrandrine could be a novel and effective drug candidate for lung fibrosis and senescence-related fibrotic diseases.

RNF130 protects against pulmonary fibrosis through suppressing aerobic glycolysis by mediating c-myc ubiquitination.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal disease,characterized by an excessive accumulation of extracellular matrix (ECM) proteins in response to chronic lung injury. Current evidence suggests that metabolic reprogramming is always accompanied by myofibroblast activation in IPFof whichthe underlying mechanisms remain unclear. Ring finger protein 130 (RNF130), was demonstrated involved in multiple diseases. However, whether RNF130 plays a critical role in the pathogenesis of IPF needs to be clarified. METHODS: We first investigated the expression of RNF130 in pulmonary fibrosis in vivo and in vitro. We then observed the effect and explored the molecular mechanism of RNF130 on the transition of fibroblast to myofibroblast and aerobic glycolysis. Further, we assessed the effects of adeno-associated virus (AAV)-induced RNF130 overexpression in the pulmonary fibrosis model, conducting pulmonary function, assessment of collagen depositionusing the hydroxyproline assay, and biochemical and histopathological analyses. RESULTS: We found that RNF130 was down-regulated in lung tissues of mice with bleomycin-induced pulmonary fibrosis and lung fibroblasts treated with transforming growth factor-ß1 (TGF-ß1). Then we demonstrated that RNF130 inhibitedthe transition of fibroblast to myofibroblast by suppressing aerobic glycolysis. Mechanistically, we revealed that RNF130 promotedc-myc ubiquitination and degradation, while c-myc overexpression reverses the inhibitory effects of RNF130. Importantly, pulmonary function, collagen deposition and fibroblast differentiation were significantly alleviated in adeno-associated virus serotype (AAV)6-RNF130 treated mice, which further validated the contribution of RNF130/c-myc signaling axis in pulmonary fibrosis pathological process. CONCLUSIONS: In summary, RNF130 participates in the pathogenesis of pulmonary fibrosis by inhibiting the transition of fibroblast to myofibroblast and aerobic glycolysis through promoting c-myc ubiquitination and degradation. Targeting RNF130-c-myc axismightrepresent a promising strategy to alleviate the progression of IPF.