GSTO1 aggravates EGFR-TKIs resistance and tumor metastasis via deglutathionylation of NPM1 in lung adenocarcinoma.

Despite significantly improved clinical outcomes in EGFR-mutant lung adenocarcinoma, all patients develop acquired resistance and malignancy on the treatment of EGFR tyrosine kinase inhibitors (EGFR-TKIs). Understanding the resistance mechanisms is crucial to uncover novel therapeutic targets to improve the efficacy of EGFR-TKI treatment. Here, integrated analysis using RNA-Seq and shRNAs metabolic screening reveals glutathione S-transferase omega 1 (GSTO1) as one of the key metabolic enzymes that is required for EGFR-TKIs resistance in lung adenocarcinoma cells. Aberrant upregulation of GSTO1 confers EGFR-TKIs resistance and tumor metastasis in vitro and in vivo dependent on its active-site cysteine 32 (C32). Pharmacological inhibition or knockdown of GSTO1 restores sensitivity to EGFR-TKIs and synergistically enhances tumoricidal effects. Importantly, nucleophosmin 1 (NPM1) cysteine 104 is deglutathionylated by GSTO1 through its active C32 site, which leads to activation of the AKT/NF-κB signaling pathway. In addition, clinical data illustrates that GSTO1 level is positively correlated with NPM1 level, NF-κB-mediated transcriptions and progression of human lung adenocarcinoma. Overall, our study highlights a novel mechanism of GSTO1 mediating EGFR-TKIs resistance and malignant progression via protein deglutathionylation, and GSTO1/NPM1/AKT/NF-κB axis as a potential therapeutic vulnerability in lung adenocarcinoma.

Cancer cell-autonomous cGAS-STING response confers drug resistance.

The cGAS-STING pathway has long been recognized as playing a crucial role in immune surveillance and tumor suppression. Here, we show that when the pathway is activated in a cancer-cell-autonomous response manner, it confers drug resistance. Targeted or conventional chemotherapy drugs promoted cytosolic DNA accumulation in cancer cells, activating the cGAS-STING pathway and downstream TBK1-IRF3/NF-κB signaling. This cancer cell-intrinsic response enabled the cells to counteract drug stress, allowing treatment resistance to be acquired and maintained. Blockade of stimulator of interferon genes (STING) signaling delayed and overcame resistance in models in vitro and in vivo. This finding uncovers an alternative face of cGAS-STING signaling other than the well-reported modulation of microenvironmental immune cells. It also implies a caution for the combination of STING agonist with targeted or conventional chemotherapy drug treatment, a strategy prevailing in current clinical trials.

Erratum: Aldehyde dehydrogenase 1A1 confers erlotinib resistance via facilitating the reactive oxygen species-reactive carbonyl species metabolic pathway in lung adenocarcinomas: Erratum.

[This corrects the article DOI: 10.7150/thno.35729.].

A phosphoglycerate mutase 1 allosteric inhibitor overcomes drug resistance to EGFR-targeted therapy via disrupting IL-6/JAK2/STAT3 signaling pathway in lung adenocarcinoma.

Resistance to epidermal growth factor receptor (EGFR) inhibitors, from the first-generation erlotinib to the third generation osimertinib, is a clinical challenge in the treatment of patients with EGFR-mutant lung adenocarcinoma. Our previous work found that a novel allosteric inhibitor of phosphoglycerate mutase 1 (PGAM1), HKB99, restrains erlotinib resistance in lung adenocarcinoma cells. However, the role of HKB99 in osimertinib resistance and its underlying molecular mechanism remains to be elucidated. Herein, we found that IL-6/JAK2/STAT3 signaling pathway is aberrantly activated in both erlotinib and osimertinib resistant cells. Importantly, HKB99 significantly blocks the interaction of PGAM1 with JAK2 and STAT3 via the allosteric sites of PGAM1, which leads to inactivation of JAK2/STAT3 and thereby disrupts IL-6/JAK2/STAT3 signaling pathway. Consequently, HKB99 remarkably restores EGFR inhibitor sensitivity and exerts synergistic tumoricidal effect. Additionally, HKB99 alone or in combination with osimertinib down-regulated the level of p-STAT3 in xenograft tumor models. Collectively, this study identifies PGAM1 as a key regulator in IL-6/JAK2/STAT3 axis in the development of resistance to EGFR inhibitors, which could serve as a therapeutic target in lung adenocarcinoma with acquired resistance to EGFR inhibitors.

Metastatic parotid gland malignancy: A preliminary study in an eastern Chinese population.

OBJECTIVE: This study aimed to determine the incidence and clinicopathological patterns of metastatic carcinoma of the parotid gland. METHOD: Ninety patients with parotid gland metastases admitted to our hospital between January 2003 and December 2018 were included in this study. Clinical and pathological data were obtained from the medical records and follow-ups. Kaplan-Meier analysis was used to assess overall survival of patients. RESULTS: Among the 90 patients, parotid gland metastases originated from the head and neck in 86 (95.6%), from non-head and neck in 4 (4.4%), from the oral cavity in 30(33.3%), and from the eyelid in 21 (23.3%). Among the 85 cases with parotid gland lymph node metastasis, 45 (52.9%) were diagnosed with extra-lymph node metastasis. The capsule of the parotid lymph nodes was thinner than that of the cervical lymph nodes (P < 0.05). Hematogenous metastases to the parotid gland (only five cases) were rare, mainly from the non-head and neck malignancies. Patients with oral squamous cell carcinoma and meibomian adenocarcinoma with parotid metastatic disease had poorer overall survival (P < 0.05). CONCLUSION: Eastern China population analysis showed that parotid gland metastases usually arise from oral squamous cell carcinoma and eyelid, but rarely from cutaneous squamous cell carcinoma. Most cases metastasize to the parotid lymph nodes via the lymphatic system and are prone to extranodal extension with little or no facial nerve involvement. These findings have important implications for the treatment of metastatic parotid malignancies.

High-quality reconstruction of China's natural streamflow.

Reconstruction of natural streamflow is fundamental to the sustainable management of water resources. In China, previous reconstructions from sparse and poor-quality gauge measurements have led to large biases in simulation of the interannual and seasonal variability of natural flows. Here we use a well-trained and tested land surface model coupled to a routing model with flow direction correction to reconstruct the first high-quality gauge-based natural streamflow dataset for China, covering all its 330 catchments during the period from 1961 to 2018. A stronger positive linear relationship holds between upstream routing cells and drainage areas, after flow direction correction to 330 catchments. We also introduce a parameter-uncertainty analysis framework including sensitivity analysis, optimization, and regionalization, which further minimizes biases between modeled and inferred natural streamflow from natural or near-natural gauges. The resulting behavior of the natural hydrological system is represented properly by the model which achieves high skill metric values of the monthly streamflow, with about 83% of the 330 catchments having Nash-Sutcliffe efficiency coefficient (NSE) > 0.7, and about 56% of the 330 catchments having Kling-Gupta efficiency coefficient (KGE) > 0.7. The proposed construction scheme has important implications for similar simulation studies in other regions, and the developed low bias long-term national datasets by statistical postprocessing should be useful in supporting river management activities in China.

Targeting DNA damage response as a potential therapeutic strategy for head and neck squamous cell carcinoma.

Cells experience both endogenous and exogenous DNA damage daily. To maintain genome integrity and suppress tumorigenesis, individuals have evolutionarily acquired a series of repair functions, termed DNA damage response (DDR), to repair DNA damage and ensure the accurate transmission of genetic information. Defects in DNA damage repair pathways may lead to various diseases, including tumors. Accumulating evidence suggests that alterations in DDR-related genes, such as somatic or germline mutations, single nucleotide polymorphisms (SNPs), and promoter methylation, are closely related to the occurrence, development, and treatment of head and neck squamous cell carcinoma (HNSCC). Despite recent advances in surgery combined with radiotherapy, chemotherapy, or immunotherapy, there has been no substantial improvement in the survival rate of patients with HNSCC. Therefore, targeting DNA repair pathways may be a promising treatment for HNSCC. In this review, we summarized the sources of DNA damage and DNA damage repair pathways. Further, the role of DNA damage repair pathways in the development of HNSCC and the application of small molecule inhibitors targeting these pathways in the treatment of HNSCC were focused.

Metabolic and Nonmetabolic Functions of PSAT1 Coordinate Signaling Cascades to Confer EGFR Inhibitor Resistance and Drive Progression in Lung Adenocarcinoma.

Emerging evidence demonstrates that the dysregulated metabolic enzymes can accelerate tumorigenesis and progression via both metabolic and nonmetabolic functions. Further elucidation of the role of metabolic enzymes in EGFR inhibitor resistance and metastasis, two of the leading causes of death in lung adenocarcinoma, could help improve patient outcomes. Here, we found that aberrant upregulation of phosphoserine aminotransferase 1 (PSAT1) confers erlotinib resistance and tumor metastasis in lung adenocarcinoma. Depletion of PSAT1 restored sensitivity to erlotinib and synergistically augmented the tumoricidal effect. Mechanistically, inhibition of PSAT1 activated the ROS-dependent JNK/c-Jun pathway to induce cell apoptosis. In addition, PSAT1 interacted with IQGAP1, subsequently activating STAT3-mediated cell migration independent of its metabolic activity. Clinical analyses showed that PSAT1 expression positively correlated with the progression of human lung adenocarcinoma. Collectively, these findings reveal the multifunctionality of PSAT1 in promoting tumor malignancy through its metabolic and nonmetabolic activities. SIGNIFICANCE: Metabolic and nonmetabolic functions of PSAT1 confer EGFR inhibitor resistance and promote metastasis in lung adenocarcinoma, suggesting therapeutic targeting of PSAT1 may attenuate the malignant features of lung cancer.

Spatiotemporal hysteresis distribution and decomposition of solar activities and climatic oscillation during 1900-2020.

Solar radiation is the external driving force of the Earth's climate system. In different spatial and temporal scales, meteorological elements have different responses and lag periods to solar activity (SA), climatic oscillation (CO), geographic factors (GF) and other influencing factors. However, such studies are not abundant and in-depth in the world. To further understand the "solar-climate-water resource" system, this study considers China as the study area and investigates the monthly data of temperature (T) and precipitation (P) during 1900-2020 that were obtained from 3836 grid stations. The strong interaction and lag distribution between T or P with SA and CO were studied and influence weights of SA, CO, and geographical factors (GF) of each grid station were calculated. A multivariate hysteretic decomposition model was established to simulate and quantitatively decompose the periodic lag considering the factors of the earth's revolution. It is found that the strong interaction/lag periods obtained in a long-time scale can be decomposed into several periods shorter than the SA period. The distribution of strong interaction/lag periods is nested with topography and echoes with cities. The underlying surface conditions and urbanization are also important factors affecting the T and P lag. There are two distinct dividing lines in the lag period and influencing factor pattern of T and P. The T dividing line moves through valleys where water or mountain ranges meet, where the gap facilitates monsoon movement across regions, while the P dividing line is a zone of dramatic terrain, where tall mountains block water vapor transport. In the lag trend of T, the northern region of China has the longest lag period, and the lag period of surrounding regions tends to converge to the northern region. The lag period caused by SN in southwest China is larger than that in northwest China, while the lag effect of CO is opposite in the above two regions. The lag trend of P also has the above characteristics, but the difference is that the lag period in central China is the longest.

Targeting AKR1B1 inhibits glutathione de novo synthesis to overcome acquired resistance to EGFR-targeted therapy in lung cancer.

Acquired resistance represents a bottleneck to molecularly targeted therapies such as epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment in lung cancer. A deeper understanding of resistance mechanisms can provide insights into this phenomenon and help to develop additional therapeutic strategies to overcome or delay resistance. Here, we identified a pharmacologically targetable metabolic mechanism that drives resistance to EGFR TKIs in lung cancer cell lines and patient-derived xenograft mice. We demonstrated that aldo-keto reductase family 1 member B1 (AKR1B1) interacts with and activates signal transducer and activator of transcription 3 (STAT3) to up-regulate the cystine transporter solute carrier family 7 member 11 (SLC7A11). This leads to enhanced cystine uptake and flux to glutathione de novo synthesis, reactive oxygen species (ROS) scavenging, protection from cell death, and EGFR TKI drug resistance in lung cancer cell lines and xenograft mouse models. Suppression of AKR1B1 with selective inhibitors, including the clinically approved antidiabetic drug epalrestat, restored the sensitivity of resistant cell lines to EGFR TKIs and delayed resistance in lung cancer patient-derived xenograft mice. Our findings suggest a metabolic mechanism for resistance to a molecularly targeted therapy and provide a potential therapeutic target for overcoming resistance to EGFR TKIs, including the third-generation inhibitor osimertinib.

Molecular dynamics study of conformation transition from helix to sheet of Aß42 peptide.

Aß42 peptides can form helix and sheet structure under different conditions. The conformational conversion is closely associated with Aß peptides aggregation and their neurotoxicity. But the transition from helix to sheet is not be clearly understood. In this study we performed microsecond timescale MD simulations of Aß42 peptide to investigate the conformation transition from α-helix to ß-sheet. Markov state model (MSM) was built to facilitate identification of crucial intermediate states and possible transition pathway. Based on the analysis, we found that the region Y10-A21 in the middle of Aß42 peptide plays an initial role in this transition. MSM model revealed that the collapse of helical structure in this region might trigger the formation of sheet structure. Moreover, we further simulated the aggregation of Aß42 peptides with different conformations. We found that the Aß42 peptides forming sheet structure have higher aggregation potential compared with peptides with helix structure. These results demonstrate that we can prevent the aggregation of Aß42 peptides by stabilizing the helix structure in the region of Y10-A21. In addition, this study provides new insight into better understanding the conformational transition and aggregation of Aß42 peptides.

Analysis of soil respiration and influencing factors in a semiarid dune-meadow cascade ecosystem.

The characteristics of soil respiration (Rs) in semiarid regions are important with regard to the carbon cycle of complex underlying surfaces and estimation of carbon emissions from regional ecosystems. During the growing season (May-September 2016), in situ observations of Rs were obtained concurrently with measurements of soil bacteria (Bs), soil moisture (Ms), and soil temperature (Ts) at depths of 0-10 cm, in a dune-meadow cascade ecosystem. Results showed that Rs differences among the various ecosystems were significant (P < 0.01), the intensity of Rs in meadows was twice stronger than that in dunes. The average values of Rs presenting a declined trend follows MPA (11.19 µmol m-2 s-1) > MAF (7.75) > SSG (6.78) > SMAH (5.02) > SFAH (4.8) > FLC (4.28) > SBG (3.09). An extremely significant (p < 0.01) positive correlated power relationship can be found between Rs and Bs, which could explain 62.41%-86.56% of the variation in Rs in the various ecosystems. Field capacity and the saturated water content were the key demarcation points for the interactive relationship between Rs and Ms, which showing a significant (P < 0.05) positive correlated power relationship in dunes, in contrast, it presenting a significant (P < 0.05) negative correlated exponential relationship in meadows. Rs was positively exponentially correlated with Ts, significant (P < 0.05) in meadows and nonsignificant (P > 0.05) in dunes. Future research should be strengthened to consider multiple growing seasons experiencing various climatic conditions for accurate estimation of terrestrial carbon emissions in arid and semiarid ecosystems.

Comparison of an improved Penman-Monteith model and SWH model for estimating evapotranspiration in a meadow wetland in a semiarid region.

Accurately estimating evapotranspiration (ET) for meadow wetland ecosystems is of great significance for water management in semiarid regions. Taking a meadow wetland ecosystem in the Horqin Sandy Land as an example, this study coupled the Ball-Berry canopy stomatal conductance model to Penman-Monteith (P-M) model and Shuttleworth-Wallace (S-W) model, and the improved P-M model and SWH model were calibrated and validated by long-term (2013-2018 growing seasons) eddy covariance (EC) measurements. The results indicated that the improved P-M model and SWH model performed well either at half-hourly or daily timescales, with high coefficient of determination (R2) and index of agreement (IA) and low root mean square error (RMSE). Generally, the SWH model performed better than the improved P-M model, especially under the low leaf area index (LAI) conditions. In addition, in the growing seasons from 2013 to 2018, the mean ET measured by the EC system was 2.78 mm/d, which was approximately equal to the mean modeled ET from the SWH model (2.75 mm/d) and slightly higher than the mean modeled ET from the improved P-M model (2.34 mm/d). The improved P-M model and SWH model were highly sensitive to the parameter in estimating canopy surface resistance and to vapor pressure deficit (VPD) in meteorological variables.

Hydrologic gradient changes of soil respiration in typical steppes of Eurasia.

Soil respiration (RS) is affected by many factors and shows significant diurnal and seasonal changes at different spatial and temporal scales. However, in a semi-arid steppe, the mechanism of the dynamic influence of environmental factors on RS is not clear, and the effect of subtle changes of soil water on RS under drought stress is yet to be explored. Therefore, Xilin River Basin, was the study area and a hydrological gradient on the four ecosystems for RS and hydrometeorological monitoring was selected. We proposed the use of dynamic sunrise and sunset time to distinguish day from night and determine related statistics. Additionally, we analyzed the temporal variation of RS and its response process and mechanism for hydrometeorological factors during the growing season and at daily scales. Further, we quantitatively simulated the RS of 594 scenarios in different growing season stages, ecosystems, and precipitation patterns. Results showed that: (1) in the hydrological gradient belt, different ecosystems exhibited the same trend but different characteristics of RS regulation. From May to November 2020, RS was 2.34-3.89, 1.89-5.97, 1.90-5.27 and 2.29-3.45 gC m-2 day-1 for the four ecosystems. (2) The use of dynamic sunrise and sunset time to distinguish day and night can more accurately describe the statistical value of each variable, which exhibits remarkable feasibility in daily scale research. (3) The changes in RS were adequately explained by temperature at various time scales, and the photosynthetically active radiation was positively correlated with RS at the daily scale. The special soil water content (MS) condition in the study area was not sufficient to explain RS. (4) Precipitation can affect RS by changing soil and air; however, only when precipitation exceeds the effective precipitation threshold of 0.6 ± 0.3 mm, it significantly affects RS.

Erratum: Overcoming erlotinib resistance in EGFR mutation-positive lung adenocarcinomas through repression of phosphoglycerate dehydrogenase: Erratum.

[This corrects the article DOI: 10.7150/thno.23177.].

HKB99, an allosteric inhibitor of phosphoglycerate mutase 1, suppresses invasive pseudopodia formation and upregulates plasminogen activator inhibitor-2 in erlotinib-resistant non-small cell lung cancer cells.

Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as erlotinib, remains a major challenge in the targeted therapy of non-small cell lung cancer (NSCLC). HKB99 is a novel allosteric inhibitor of phosphoglycerate mutase 1 (PGAM1) that preferentially suppresses cell proliferation and induces more apoptosis in acquired erlotinib-resistant HCC827ER cells compared with its parental HCC827 cells. In this study we identified the molecular biomarkers for HKB99 response in erlotinib-resistant HCC827ER cells. We showed that HCC827ER cells displayed enhanced invasive pseudopodia structures as well as downregulated plasminogen activator inhibitor-2 (PAI-2). Meanwhile, PAI-2 knockdown by siPAI-2 candidates decreased the sensitivity of HCC827 parental cells to erlotinib. Moreover, HKB99 (5 µM) preferentially inhibited the invasive pseudopodia formation and increased the level of PAI-2 in HCC827ER cells. Collectively, this study provides new insight into the role of PAI-2 in regulating the sensitivity of erlotinib resistant NSCLC cells to PGAM1 inhibitor. Furthermore, PAI-2 level might be considered as a potential biomarker for predicting the efficacy of the PGAM1 allosteric inhibitor on the erlotinib resistant NSCLC cells.

NRF2-GPX4/SOD2 axis imparts resistance to EGFR-tyrosine kinase inhibitors in non-small-cell lung cancer cells.

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have achieved satisfactory clinical effects in the therapy of non-small cell lung cancer (NSCLC), but acquired resistance limits their clinical application. NRF2 has been shown to enhance the resistance to apoptosis induced by radiotherapy and some chemotherapy. In this study, we investigated the role of NRF2 in resistance to EGFR-TKIs. We showed that NRF2 protein levels were markedly increased in a panel of EGFR-TKI-resistant NSCLC cell lines due to slow degradation of NRF2 protein. NRF2 knockdown overcame the resistance to EGFR-TKIs in HCC827ER and HCC827GR cells. Furthermore, we demonstrated that NRF2 imparted EGFR-TKIs resistance in HCC827 cells via upregulation of GPX4 and SOD2, and suppression of GPX4 and SOD2 reversed resistance to EGFR-TKIs. Thus, we conclude that targeting NRF2-GPX4/SOD2 pathway is a potential strategy for overcoming resistance to EGFR-TKIs.

Development and validation of a rapid, robust and sensitive UPLC-QQQ-MS/MS method for simultaneous quantification of GSH metabolism in lung cancer cells.

Changes in cellular metabolism accompany tumor therapeutic resistance. Metabolite concentrations specifically reflect the cellular state. Glutathione (GSH) metabolism maintains the redox homeostasis while also confers therapeutic resistance to cancer cells. However, analytical methods for studying GSH metabolism rely on high-resolution-based untargeted metabolomics. Since the aim of untargeted metabolomics studies is covering as much metabolites as possible, these methods lack sensitivity for simultaneous analysis of intracellular GSH-related metabolites with different polarities and structures. In this study, based on cultured lung cancer cells, we described a rapid, robust and sensitive ultra-performance liquid chromatography-triple quadrupole tandem mass spectrographic method (UPLC-QQQ-MS/MS) to simultaneously quantify a repertoire of GSH-related metabolites, including GSH, GSSG, glycine, cysteine, glutamine, glutamate, cystine, γ-glutamyl-cysteine and cysteinyl-glycine. This method avoided the use of derivatization and/or ion-pairing reagents and was validated according to United States Food and Drug Administration (US FDA) criteria. The lower limit of quantification was determined to be 0.5-100 ng/mL with lower limits of detection at 0.14-10.07 ng/mL. The intra- and inter-day precision values for all the analytes were <15% CV, and the accuracy ranged from 85.4% to 114% at three levels of quality control. This method combined simple preparation with rapid analytical procedure (8 min), allowed for high-throughput analysis of GSH metabolism in basic and therapeutic treatment conditions within cultured cells. Our data showed a significant alteration of GSH metabolism in two independent resistant cells compared to sensitive cells. This method monitored the impact of molecularly targeted drugs on GSH metabolism within lung cancer cells and therefore helped identifying potential metabolic vulnerability for the therapeutic resistance in lung cancer.