HuaChanSu suppresses the growth of hepatocellular carcinoma cells by interfering with pentose phosphate pathway through down-regulation of G6PD enzyme activity and expression.

HuaChanSu is active water extracts from the skin of Bufo bufo gargarizans Cantor. It has been already used to treat clinical cancers including HCC (Hepatocellular carcinoma, HCC), however, the molecular mechanisms under HuaChanSu's anti-cancer effects remain unclear. PPP (Pentose phosphate pathway, PPP), the major source of ribose and NADPH (Nicotinamide adenine dinucleotide phosphate, NADPH), is always over-activated and particularly critical for tumor cells growth. In this study, firstly, we illustrate that HuaChanSu restrains the growth of human hepatoma cells. More importantly, we demonstrate that the expression of G6PD (Glucose-6-phosphate dehydrogenase, G6PD), the first rate-limiting enzyme of the PPP, is restrained in human hepatoma cells after treatment with HuaChanSu. Additionally, our results show that G6PD enzyme activity and dimer formation are inhibited by HuaChanSu. Furthermore, we find that HuaChanSu could inhibit NADPH production and nucleotide level. In addition, we identify that expression of PLK1 (Polo-like kinase 1, PLK1) is also reduced in response to HuaChanSu, and knockdown of PLK1 restrains enzyme activity and dimer formation of G6PD, but has no effect on G6PD protein level. Subsequently, we demonstrate that inhibition of G6PD could restrain the proliferation of tumor cells and enhance the inhibitory effect of HuaChanSu on cell proliferation of human hepatoma cells. In conclusion, for the first time, our study reveals that HuaChanSu interferes with PPP via suppression of G6PD expression and enzyme activity to restrain growth of tumor cells, and these results provide a novel insight for the anti-hepatoma mechanisms of HuaChanSu and promote the innovation of the research model of TCM. Moreover, the development of drugs targeting abnormal tumor metabolism is currently a hot topic, our works provide theoretical support for further drug development from HuaChanSu, meanwhile, the revelation of the new molecular mechanism also provides a new perspective for the study of the pathogenesis of liver cancer. Short abstract: HuaChanSu suppresses expression of G6PD, the first rate-limiting enzyme of the PPP, restrains G6PD enzyme activity and dimer formation via inhibition of PLK1, knockdown of G6PD could impair the growth of human hepatoma cells and increase the blocking effect of HuaChanSu on cell proliferation of cancer cells. In addition, HuaChanSu restrains NADPH production and nucleotide level, implying the suppression of PPP flux. Our study suggests that HuaChanSu interferes with PPP via G6PD inhibition to exert anti-hepatoma effects.

Interfering with the AKT/mTOR/STAT3/ID1 signaling axis with usenamine A restrains the proliferative and invasive potential of human hepatocellular carcinoma cells.

BACKGROUND: Usenamine A, a novel natural compound initially isolated from the lichen Usnea longissima, has exhibited promising efficacy against hepatoma in prior investigation. Nevertheless, the underlying mechanisms responsible for its antihepatoma effects remain unclear. Furthermore, the role of the AKT/mechanistic target of the rapamycin (mTOR)/signal transducer and activator of transcription 3 (STAT3)/inhibitor of differentiation/DNA binding 1 (ID1) signaling axis in hepatocellular carcinoma (HCC), and the potential anti-HCC effects of drugs targeting this pathway are not well understood. METHODS: CCK-8 assay was used to investigate the effects of usenamine A on the proliferation of human HCC cells. Moreover, the effects of usenamine A on the invasion ability of human HCC cells were evaluated by transwell assay. In addition, expression profiling analysis, quantitative real-time PCR, immunoblotting, immunohistochemistry (IHC) analysis, RNAi, immunoprecipitation, and chromatin immunoprecipitation (ChIP) assay were used to explore the effects of usenamine A on the newly identified AKT/mTOR/STAT3/ID1 signaling axis in human HCC cells. RESULTS: Usenamine A inhibited the proliferation and invasion of human HCC cell lines (HepG2 and SK-HEP-1). Through the analysis of gene expression profiling, we identified that usenamine A suppressed the expression of ID1 in human HCC cells. Furthermore, immunoprecipitation experiments revealed that usenamine A facilitated the degradation of the ID1 protein via the ubiquitin-proteasome pathway. Moreover, usenamine A inhibited the activity of STAT3 in human HCC cells. ChIP analysis demonstrated that STAT3 positively regulated ID1 expression at the transcriptional level in human HCC cells. The STAT3/ID1 axis played a role in mediating the anti-proliferative and anti-invasive impacts of usenamine A on human HCC cells. Additionally, usenamine A suppressed the STAT3/ID1 axis through AKT/mTOR signaling in human HCC cells. CONCLUSION: Usenamine A displayed robust anti-HCC potential, partly attributed to its capacity to downregulate the AKT/mTOR/STAT3/ID1 signaling pathway and promote ubiquitin-proteasome-mediated ID1 degradation. Usenamine A has the potential to be developed as a therapeutic agent for HCC cases characterized by abnormal AKT/mTOR/STAT3/ID1 signaling, and targeting the AKT/mTOR/STAT3 signaling pathway may be a viable option for treating patients with HCC exhibiting elevated ID1 expression.

Soluble epoxide hydrolase deficiency attenuates airway inflammation in COPD via IRE1α/JNK/AP-1 signaling pathway.

BACKGROUND: Soluble Epoxide Hydrolase (sEH) metabolizes anti-inflammatory epoxyeicosatrienoic acids and critically affects airway inflammation in chronic obstructive pulmonary disease (COPD). Considering the excessive endoplasmic reticulum stress is associated with the earlier onset of COPD. The role of sEH and endoplasmic reticulum stress in the pathogenesis of COPD remains unknown. METHOD: 16 weeks of cigarette-exposed mice were used to detect the relationship between sEH and endoplasmic reticulum stress in COPD. Human epithelial cells were used in vitro to determine the regulation mechanism of sEH in endoplasmic reticulum stress induced by cigarette smoke. RESULTS: sEH deficiency helps reduce emphysema formation after smoke exposure by alleviating endoplasmic reticulum stress response. sEH deficiency effectively reverses the upregulation of phosphorylation IRE1α and JNK and the nuclear expression of AP-1, alleviating the secretion of inflammatory factors induced by cigarette smoke extract. Furthermore, the treatment with endoplasmic reticulum stress and IRE1α inhibitor downregulated cigarette smoke extract-induced sEH expression and the secretion of inflammatory factors. CONCLUSION: sEH probably alleviates airway inflammatory response and endoplasmic reticulum stress via the IRE1α/JNK/AP-1 pathway, which might attenuate lung injury caused by long-term smoking and provide a new pharmacological target for preventing and treating COPD.

MFN2 deficiency promotes cardiac response to hypobaric hypoxia by reprogramming cardiomyocyte metabolism.

AIM: Under hypobaric hypoxia (HH), the heart triggers various defense mechanisms including metabolic remodeling against lack of oxygen. Mitofusin 2 (MFN2), located at the mitochondrial outer membrane, is closely involved in the regulation of mitochondrial fusion and cell metabolism. To date, however, the role of MFN2 in cardiac response to HH has not been explored. METHODS: Loss- and gain-of-function approaches were used to investigate the role of MFN2 in cardiac response to HH. In vitro, the function of MFN2 in the contraction of primary neonatal rat cardiomyocytes under hypoxia was examined. Non-targeted metabolomics and mitochondrial respiration analyses, as well as functional experiments were performed to explore underlying molecular mechanisms. RESULTS: Our data demonstrated that, following 4 weeks of HH, cardiac-specific MFN2 knockout (MFN2 cKO) mice exhibited significantly better cardiac function than control mice. Moreover, restoring the expression of MFN2 clearly inhibited the cardiac response to HH in MFN2 cKO mice. Importantly, MFN2 knockout significantly improved cardiac metabolic reprogramming during HH, resulting in reduced capacity for fatty acid oxidation (FAO) and oxidative phosphorylation, and increased glycolysis and ATP production. In vitro data showed that down-regulation of MFN2 promoted cardiomyocyte contractility under hypoxia. Interestingly, increased FAO through palmitate treatment decreased contractility of cardiomyocyte with MFN2 knockdown under hypoxia. Furthermore, treatment with mdivi-1, an inhibitor of mitochondrial fission, disrupted HH-induced metabolic reprogramming and subsequently promoted cardiac dysfunction in MFN2-knockout hearts. CONCLUSION: Our findings provide the first evidence that down-regulation of MFN2 preserves cardiac function in chronic HH by promoting cardiac metabolic reprogramming.

MFN2-mediated mitochondrial fusion facilitates acute hypobaric hypoxia-induced cardiac dysfunction by increasing glucose catabolism and ROS production.

BACKGROUND: Rapid ascent to high-altitude environment which is characterized by acute hypobaric hypoxia (HH) may increase the risk of cardiac dysfunction. However, the potential regulatory mechanisms and prevention strategies for acute HH-induced cardiac dysfunction have not been fully clarified. Mitofusin 2 (MFN2) is highly expressed in the heart and is involved in the regulation of mitochondrial fusion and cell metabolism. To date, however, the significance of MFN2 in the heart under acute HH has not been investigated. METHODS AND RESULTS: Our study revealed that MFN2 upregulation in hearts of mice during acute HH led to cardiac dysfunction. In vitro experiments showed that the decrease in oxygen concentration induced upregulation of MFN2, impairing cardiomyocyte contractility and increasing the risk of QT prolongation. Additionally, acute HH-induced MFN2 upregulation promoted glucose catabolism and led to excessive mitochondrial reactive oxygen species (ROS) production in cardiomyocytes, ultimately resulting in decreased mitochondrial function. Furthermore, co-immunoprecipitation (co-IP) and mass spectrometry analyses indicated that MFN2 interacted with the NADH-ubiquinone oxidoreductase 23 kDa subunit (NDUFS8). Specifically, acute HH-induced MFN2 upregulation increased NDUFS8-dependent complex I activity. CONCLUSIONS: Taken together, our studies provide the first direct evidence that MFN2 upregulation exacerbates acute HH-induced cardiac dysfunction by increasing glucose catabolism and ROS production. GENERAL SIGNIFICANCE: Our studies indicate that MFN2 may be a promising therapeutic target for cardiac dysfunction under acute HH.

Usenamine A induces apoptosis and autophagic cell death of human hepatoma cells via interference with the Myosin-9/actin-dependent cytoskeleton remodeling.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major cause of cancer-associated mortality worldwide. Myosin-9's role in HCC and the anti-HCC effect of the drugs targeting Myosin-9 remain poorly understood so far. Candidate antitumor agents obtained from natural products have attracted worldwide attention. Usenamine A is a novel product, which was first extracted in our laboratory from the lichen Usnea longissima. According to published reports, usenamine A exhibits good antitumor activity, while the mechanisms underlying its antitumor effects remain to be elucidated. PURPOSE: The present study investigated the anti-hepatoma effect of usenamine A and the underlying molecular mechanisms, along with evaluating the therapeutic potential of targeting Myosin-9 in HCC. METHODS: The CCK-8, Hoechst staining, and FACS assays were conducted in the present study to investigate how usenamine A affected the growth and apoptosis of human hepatoma cells. Moreover, TEM, acridine orange staining, and immunofluorescence assay were performed to explore the induction of autophagy by usenamine A in human hepatoma cells. The usenamine A-mediated regulation of protein expression in human hepatoma cells was analyzed using immunoblotting. MS analysis, SPR assay, CETSA, and molecular modeling were performed to identify the direct target of usenamine A. Immunofluorescence assay and co-immunoprecipitation assay were conducted to determine whether usenamine A affected the interaction between Myosin-9 and the actin present in human hepatoma cells. In addition, the anti-hepatoma effect of usenamine A was investigated in vivo using a xenograft tumor model and the IHC analysis. RESULTS: The present study initially revealed that usenamine A could suppress the proliferation of HepG2 and SK-HEP-1 cells (hepatoma cell lines). Furthermore, usenamine A induced cell apoptosis via the activation of caspase-3. In addition, usenamine A enhanced autophagy. Moreover, usenamine A administration could dramatically suppress the carcinogenic ability of HepG2 cells, as evidenced by the nude mouse xenograft tumor model. Importantly, it was initially revealed that Myosin-9 was a direct target of usenamine A. Usenamine A could block cytoskeleton remodeling through the disruption of the interaction between Myosin-9 and actin. Myosin-9 participated in suppressing proliferation while inducing apoptosis and autophagy in response to treatment with usenamine A. In addition, Myosin-9 was revealed as a potential oncogene in HCC. CONCLUSIONS: Usenamine A was initially revealed to suppress human hepatoma cells growth by interfering with the Myosin-9/actin-dependent cytoskeleton remodeling through the direct targeting of Myosin-9. Myosin-9 is, therefore, a promising candidate target for HCC treatment, while usenamine A may be utilized as a possible anti-HCC therapeutic, particularly in the treatment of HCC with aberrant Myosin-9.

DHMMF, a natural flavonoid from Resina Draconis, inhibits hepatocellular carcinoma progression via inducing apoptosis and G2/M phase arrest mediated by DNA damage-driven upregulation of p21.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and is extremely malignant in nature. It is an important way to discover anti-cancer drugs from natural products at present. (R)-7,3'-dihydroxy-4'-methoxy-8-methylflavane (DHMMF), a natural flavonoid, was isolated from Resina Draconis which is the red resin from Dracaena cochinchinensis (Lour.) S. C. Chen. However, the anti-hepatoma effect and underlying mechanisms of DHMMF remain unclear. Herein, we demonstrated that DHMMF treatment significantly inhibited the proliferation of human hepatoma HepG2 and SK-HEP-1 cells. The IC50 value of DHMMF for HepG2 and SK-HEP-1 cells were 0.67 µM and 0.66 µM, respectively, while the IC50 value of DHMMF for human normal liver LO2 cells was 120.60 µM. DHMMF induced DNA damage, apoptosis, and G2/M phase arrest in HepG2 and SK-HEP-1 cells. Furthermore, the anti-proliferative and pro-apoptotic effects of DHMMF in human hepatoma cells were mediated by the upregulation of p21. Importantly, DHMMF exhibited potent anti-HCC efficacy in a xenograft mice model and an orthotopic mice model of liver cancer. Additionally, the combined administration of DHMMF and polo-like kinase 1 (PLK1) inhibitor BI 6727 showed a synergistic anti-HCC efficacy. Collectively, we demonstrated that DHMMF treatment induced apoptosis and G2/M phase arrest via DNA damage-driven upregulation of p21 expression in human hepatoma cells. DHMMF may serve as a promising drug candidate for HCC treatment, especially for patients of HCC with low p21 expression. Our results also suggested that DHMMF treatment in combination with PLK1 inhibitor may serve as a potential treatment strategy for patients with HCC.

Integrated transcriptomics and metabolomics analyses to investigate the anticancer mechanisms of cinobufagin against liver cancer through interfering with lipid, amino acid, carbohydrate, and nucleotide metabolism.

Liver cancer has characteristics of high morbidity, high mortality, and poor prognosis. Metabolic reprogramming is a prominent characteristic of tumors and plays a key role in promoting tumorigenesis. The metabolic process of liver cancer cells has undergone many significant changes including abnormal active glycolysis, enhanced de novo synthesis of fatty acids, and hyperactive metabolism of amino acids and nucleotides. Targeting metabolic reprogramming through regulation of anomalously expressed key metabolic enzymes and signaling molecules is considered to be an important strategy for liver cancer treatment. Multi-omics association analyses currently facilitate precise diagnosis, personalized clinical therapy, and revelation of mechanisms of drug action. Cinobufagin, as the major anti-tumor active ingredient of Chansu, the famous chinese medicine used in clinic for cancer treatment, has been reported to exert anticancer effects through many different kinds of mechanisms, but the effects of cinobufagin on metabolic reprogramming of cancer cells still remain unclear. In our study, we identify that cinobufagin exhibits anti-hepatoma effects through interfering with metabolic reprogramming (lipid, amino acid, carbohydrate, and nucleotide metabolism) based on integrated transcriptomics and metabolomics analyses. Furthermore, the results of integrated multi-omics analyses enrich various core regulatory mechanisms of anti-tumor effects of cinobufagin which are associated with metabolic pathway. In addition, some verifications of the enriched mechanisms related to intervention of lipid and carbohydrate metabolism in response to cinobufagin are also performed. This work will promote the innovation of the research model of TCM, and lay a solid theoretical foundation for the clinical application of cinobufagin and Chansu.

[Spatiotemporal Characteristics of Dissolved Oxygen and Control Mechanism of Hypoxia (Low Oxygen) in the Watershed-Coastal System in Fujian Province].

Dissolved oxygen is a key parameter to measure water environment quality and ecosystem health. Currently, the problem of hypoxia (low oxygen) is prominent in coastal areas in China, but there is a lack of research on the spatiotemporal characteristics of dissolved oxygen and the control mechanism of hypoxia in the watershed-coastal system. Based on the data of 135 surface water (including estuaries) and 66 coastal water monitoring sites in Fujian Province from 2011 to 2020, this study analyzed the spatiotemporal variation pattern of dissolved oxygen at seasonal and interannual time scales. The data of hypoxia (10% quantile, corresponding to 67% saturation) were selected to study the characteristics and control mechanism of hypoxia in four types of water bodies (i.e., rivers, reservoirs, estuaries, and coastal waters) using mathematical statistics and a random forest model. The results showed that the dissolved oxygen saturation was the highest in the coast[(98.2±10.2)%] and the lowest in the estuary[(79.2±17.9)%]. Compared with that in the 12th Five-Year Plan (2011-2015), the frequency of hypoxia detection in rivers and reservoirs in the 13th Five-Year Plan (2016-2020) was significantly reduced, but the change in estuaries was not significant. Counting the points with hypoxia detection, the multi-year average hypoxia detection frequency of rivers and reservoirs was highest in autumn, and the frequency of estuaries was highest in summer. Hypoxia in reservoirs and estuaries was the most prominent but with different mechanisms. Specifically, hypoxia in reservoir reaches was related to summer runoff carrying large amounts of organic matter input, stratification leading to continuous oxygen depletion in the bottom water, and vertical mixing or discharge through dams in autumn, whereas hypoxia in estuaries was associated with strong pollution inputs and reductive materials. Systematic management and regionalized control mechanisms need to be established to further strengthen watershed-coastal pollution abatement to help mitigate eutrophication and hypoxia problems.

Endoplasmic Reticulum Stress in Chronic Obstructive Pulmonary Disease: Mechanisms and Future Perspectives.

The endoplasmic reticulum (ER) is an integral organelle for maintaining protein homeostasis. Multiple factors can disrupt protein folding in the lumen of the ER, triggering ER stress and activating the unfolded protein response (UPR), which interrelates with various damage mechanisms, such as inflammation, apoptosis, and autophagy. Numerous studies have linked ER stress and UPR to the progression of chronic obstructive pulmonary disease (COPD). This review focuses on the mechanisms of other cellular processes triggered by UPR and summarizes drug intervention strategies targeting the UPR pathway in COPD to explore new therapeutic approaches and preventive measures for COPD.