SERPINE2 promotes liver cancer metastasis by inhibiting c-Cbl-mediated EGFR ubiquitination and degradation.

BACKGROUND: Liver cancer is a malignancy with high morbidity and mortality rates. Serpin family E member 2 (SERPINE2) has been reported to play a key role in the metastasis of many tumors. In this study, we aimed to investigate the potential mechanism of SERPINE2 in liver cancer metastasis. METHODS: The Cancer Genome Atlas database (TCGA), including DNA methylation and transcriptome sequencing data, was utilized to identify the crucial oncogene associated with DNA methylation and cancer progression in liver cancer. Data from the TCGA and RNA sequencing for 94 pairs of liver cancer tissues were used to explore the correlation between SERPINE2 expression and clinical parameters of patients. DNA methylation sequencing was used to detect the DNA methylation levels in liver cancer tissues and cells. RNA sequencing, cytokine assays, immunoprecipitation (IP) and mass spectrometry (MS) assays, protein stability assays, and ubiquitination assays were performed to explore the regulatory mechanism of SERPINE2 in liver cancer metastasis. Patient-derived xenografts and tumor organoid models were established to determine the role of SERPINE2 in the treatment of liver cancer using sorafenib. RESULTS: Based on the public database screening, SERPINE2 was identified as a tumor promoter regulated by DNA methylation. SERPINE2 expression was significantly higher in liver cancer tissues and was associated with the dismal prognosis in patients with liver cancer. SERPINE2 promoted liver cancer metastasis by enhancing cell pseudopodia formation, cell adhesion, cancer-associated fibroblast activation, extracellular matrix remodeling, and angiogenesis. IP/MS assays confirmed that SERPINE2 activated epidermal growth factor receptor (EGFR) and its downstream signaling pathways by interacting with EGFR. Mechanistically, SERPINE2 inhibited EGFR ubiquitination and maintained its protein stability by competing with the E3 ubiquitin ligase, c-Cbl. Additionally, EGFR was activated in liver cancer cells after sorafenib treatment, and SERPINE2 knockdown-induced EGFR downregulation significantly enhanced the therapeutic efficacy of sorafenib against liver cancer. Furthermore, we found that SERPINE2 knockdown also had a sensitizing effect on lenvatinib treatment. CONCLUSIONS: SERPINE2 promoted liver cancer metastasis by preventing EGFR degradation via c-Cbl-mediated ubiquitination, suggesting that inhibition of the SERPINE2-EGFR axis may be a potential target for liver cancer treatment.

FXR Maintains the Intestinal Barrier and Stemness by Regulating CYP11A1-Mediated Corticosterone Synthesis in Biliary Obstruction Diseases.

Biliary obstruction diseases are often complicated by an impaired intestinal barrier, which aggravates liver injury. Treatment of the intestinal barrier is often neglected. To investigate the mechanism by which intestinal bile acid deficiency mediates intestinal barrier dysfunction after biliary obstruction and identify a potential therapeutic modality, we mainly used a bile duct ligation (BDL) mouse model to simulate biliary obstruction and determine the important role of the bile acid receptor FXR in maintaining intestinal barrier function and stemness. Through RNA-seq analysis of BDL and sham mouse crypts and qRT-PCR performed on intestinal epithelial-specific Fxr knockout (FxrΔIEC) and wild-type mouse crypts, we found that FXR might maintain intestinal stemness by regulating CYP11A1 expression. Given the key role of CYP11A1 during glucocorticoid production, we also found that FXR activation could promote intestinal corticosterone (CORT) synthesis by ELISA. Intestinal organoid culture showed that an FXR agonist or corticosterone increased crypt formation and organoid growth. Further animal experiments showed that corticosterone gavage treatment could maintain intestinal barrier function and stemness, decrease LPS translocation, and attenuate liver injury in BDL mice. Our study hopefully provides a new theoretical basis for the prevention of intestinal complications and alleviation of liver injury after biliary obstruction.

Asialoglycoprotein Receptor 1 Functions as a Tumor Suppressor in Liver Cancer via Inhibition of STAT3.

Liver cancer is characterized by aggressive growth and high mortality. Asialoglycoprotein receptor 1 (ASGR1), which is expressed almost exclusively in liver cells, is reduced in liver cancer. However, the specific mechanism of ASGR1 function in liver cancer has not been fully elucidated. On the basis of database screening, we identified ASGR1 as a tumor suppressor regulated by DNA methylation. Expression of ASGR1 was downregulated in liver cancer and correlated with tumor size, grade, and survival. Functional gain and loss experiments showed that ASGR1 suppresses the progression of liver cancer in vivo and in vitro. RNA sequencing and mass spectrometry showed that ASGR1 inhibits tyrosine phosphorylation of STAT3 by interacting with Nemo-like kinase (NLK). NLK bound the SH2 domain of STAT3 in an ATP-dependent manner and competed with glycoprotein 130 (GP130), ultimately suppressing GP130/JAK1-mediated phosphorylation of STAT3. ASGR1 altered the binding strength of NLK and STAT3 by interacting with GP130. Furthermore, the domain region of NLK was crucial for binding STAT3 and curbing its phosphorylation. Collectively, these results confirm that ASGR1 suppresses the progression of liver cancer by promoting the binding of NLK to STAT3 and inhibiting STAT3 phosphorylation, suggesting that approaches to activate the ASGR1-NLK axis may be a potential therapeutic strategy in this disease. SIGNIFICANCE: ASGR1 downregulation by DNA methylation facilitates liver tumorigenesis by increasing STAT3 phosphorylation.

Targeting WEE1 by adavosertib inhibits the malignant phenotypes of hepatocellular carcinoma.

Targeting the cell cycle checkpoints and DNA damage response are promising therapeutic strategies for cancer. Adavosertib is a potent inhibitor of WEE1 kinase, which plays a critical role in regulating cell cycle checkpoints. However, the effect of adavosertib on hepatocellular carcinoma (HCC) treatment, including sorafenib-resistant HCC, has not been thoroughly studied. In this study, we comprehensively investigated the efficacy and pharmacology of adavosertib in HCC therapy. Adavosertib effectively inhibited the proliferation of HCC cells in vitro and suppressed tumor growth in HCC xenografts and patient-derived xenograft (PDX) models in vivo. Additionally, adavosertib treatment effectively inhibited the motility of HCC cells by impairing pseudopodia formation. Further, we revealed that adavosertib induced DNA damage and premature mitosis entrance by disturbing the cell cycle. Thus, HCC cells accumulating DNA damage underwent mitosis without G2/M checkpoint arrest, thereby leading to mitotic catastrophe and apoptosis under adavosertib administration. Given that sorafenib resistance is common in HCC in clinical practice, we also explored the efficacy of adavosertib in sorafenib-resistant HCC. Notably, adavosertib still showed a desirable inhibitory effect on the growth of sorafenib-resistant HCC cells. Adavosertib markedly induced G2/M checkpoint arrest and cell apoptosis in a dose-dependent manner, confirming the similar efficacy of adavosertib in sorafenib-resistant HCC. Collectively, our results highlight the treatment efficacy of adavosertib in HCC regardless of sorafenib resistance, providing insights into exploring novel strategies for HCC therapy.

Hypermethylation of GNA14 and its tumor-suppressive role in hepatitis B virus-related hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide, and its specific mechanism has not been fully elucidated. Inactivation of tumor suppressors may contribute to the occurrence, progression, and recurrence of HCC. DNA methylation is a crucial mechanism involved in regulating the occurrence of HCC. Herein, we aimed to identify the key methylation-related tumor suppressors as well as potential biomarkers and therapeutic targets in HCC. Methods: Combined analysis of TCGA and GEO databases was performed to obtain potential methylation-related tumor suppressors in HCC. Methyl-target sequencing was performed to analyze the methylation level of the GNA14 promoter. The diagnostic value of GNA14 as a predictor of HCC was evaluated in HCC tumor samples and compared with normal tissues. The functional role of GNA14 and its upstream and downstream regulatory factors were investigated by gain-of-function and loss-of-function assays in vitro. Subcutaneous tumorigenesis, lung colonization, and orthotopic liver tumor model were performed to analyze the role of GNA14 in vivo.Results: The expression of GNA14 was found to be downregulated in HCC and it was negatively correlated with hepatitis B virus (HBV) infection, vascular invasion, and prognosis of HCC. DNA methylation was demonstrated to be responsible for the altered expression of GNA14 and was regulated by HBV-encoded X protein (HBx). GNA14 regulated the RB pathway by promoting Notch1 cleavage to inhibit tumor proliferation, and might inhibit tumor metastasis by inhibiting the expression of JMJD6. Conclusion: GNA14 could be regulated by HBx by modulating the methylation status of its promoter. We identified GNA14 as a potential biomarker and therapeutic target for HCC.

Hint1 Overexpression Inhibits the Cell Cycle and Induces Cell Apoptosis in Human Osteosarcoma Cells.

BACKGROUND: New evidence suggests that histidine triad nucleotide-binding protein 1 (Hint1) exerts a tumor suppressor effect in various human tumors, such as colorectal cancer and gastric cancer. However, it has not been reported whether Hint1 is involved in the occurrence and development of osteosarcoma (OS). MATERIALS AND METHODS: The present study investigated the role of Hint1 in human OS cells by using cell lines, including 143B, U2OS, KHOS-240S, Saos-2 and MG-63. Cell proliferation and apoptosis were detected by flow cytometry. RESULTS: The present result revealed that Hint1 is downregulated in these cell lines. The overexpression of Hint1 by adenovirus transfection in 143B and MG63 cell lines suppressed the proliferation and cell cycle, and increased the cell apoptosis. Mechanically, it was found that Hint1 downregulated the cyclin D1 expression via FOXO1 inhibition. Furthermore, FOXO1 overexpression in the 143B and MG63 cell lines significantly blurred the effects of Hint1 on cellular proliferation and apoptosis. CONCLUSION: The present study indicates that Hint1 inhibits the development of OS by regulating FoxO1-cyclin D1, suggesting that Hint1 may be a new method for the treatment of OS.

Inhibiting the NF-κB pathway enhances the antitumor effect of cabazitaxel by downregulating Bcl-2 in pancreatic cancer.

Optimizing the currently available treatment options for pancreatic cancer (PC) is a priority. Cabazitaxel (CTX), a semisynthetic taxane, is mainly used for treating patients with PC who are resistant to paclitaxel (PTX) or docetaxel, due its poor affinity for P­glycoprotein. However, there are only a few studies demonstrating the effect of CTX on PC. The present study aimed to investigate the efficiency and underlying mechanism of CTX in PC treatment. Cell proliferation, colony formation assay and apoptosis analysis were achieved in the two human PC cell lines AsPC­1 and BxPC­3. Drug sensitivity test was performed in BxPC­3 tumor­bearing mice. The results demonstrated that CTX had a lower half maximal inhibitory concentration compared with PTX for the inhibition of cell proliferation, both in vivo and in vitro. Furthermore, the nuclear factor­κB (NF­κB) pathway was activated following cell treatment with CTX, and NF­κB p65 overexpression attenuated CTX cytotoxicity. In addition, the combined use of the specific NF­κB inhibitor caffeic acid phenethyl ester (CAPE) with CTX significantly enhanced CTX effect, both in vivo and in vitro. Similarly, the mRNA and protein expression of B­cell lymphoma-2 was decreased in AsPC­1 and BxPC­3 cells following treatment with CTX and CAPE, suggesting that NF­κB may serve a crucial role in CTX efficiency. In conclusion, results from our previous study indicated that CTX could potentially replace PTX in the treatment of PC, and the present study demonstrated that CTX combination with an NF­κB inhibitor may be considered as a potential therapeutic option for PC, which may improve the prognosis of patients with PC.

EPS8L3 promotes hepatocellular carcinoma proliferation and metastasis by modulating EGFR dimerization and internalization.

As a member of epidermal growth factor receptor (EGFR) kinase substrate 8 (EPS8) family, the role of EPS8 like 3 protein (EPS8L3) has not been well studied in malignancies. However, EPS8 has been reported to be associated with prognosis and functions in several kinds of cancers. Hence, whether EPS8L3 plays similar roles in the tumorigenesis of human cancers, especially in hepatocellular carcinoma (HCC), is still needed to be further explored. In this study, we revealed that EPS8L3 was overexpressed in HCC tissues compared with adjacent non-tumor tissues, and was associated with a poor clinical prognosis. Both in vitro and in vivo experiments showed that EPS8L3 could promote the proliferative ability by downregulating p21/p27 expression, and promote the migratory and invasive abilities by upregulating matrix metalloproteinase-2 expression. Furthermore, we demonstrated that EPS8L3 could affect the activation of the EGFR-ERK pathway by modulating EGFR dimerization and internalization, which may not depend on the formation of EPS8L3-SOS1-ABI1 complex. Taken together, our study showed that EPS8L3 plays a pivotal role in the tumorigenesis and progression of HCC, and it might be a potential therapeutic target for HCC.

CTRP12 Ameliorated Lipopolysaccharide-Induced Cardiomyocyte Injury.

C1q/tumor necrosis factor (TNF)-related protein 12 (CTRP12) is a secretory protein that participates in the regulation of glucose and lipid metabolism in obesity and diabetes. Its role in cardiovascular disease, particularly sepsis-induced cardiac injury, is unclear. Here, we stimulated cardiomyocytes with lipopolysaccharide (LPS) to establish an in vitro cardiomyocyte injury model and CTRP12 was overexpressed with an adenovirus delivery system. Overexpression of CTRP12 reduced the transcription and release of pro-inflammatory cytokines from LPS-stimulated cardiomyocytes, including TNFα, interleukin-1 (IL-1), and IL-6. Reactive oxygen species (ROS) level increased and the oxidation/redox system was disturbed in LPS-stimulated cardiomyocytes, as evident from the decrease in superoxide dismutase activity and an increase in reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and malondialdehyde level. CTRP12 overexpression decreased the increasing level of ROS and ameliorated the unbalance in the oxidation/redox system in LPS-stimulated cardiomyocytes. The viability of cardiomyocytes decreased after LPS stimulation, and the cells underwent apoptosis. CTRP12-overexpressing cardiomyocytes showed a decrease in the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells, and the ratio of B cell lymphoma (Bcl)-1/Bax in these cells was recovered. In comparison with the control group, LPS-stimulated cardiomyocytes showed reduced expression of nuclear factor E2-related factor 2 (NRF2), while CTRP12-overexpressing cardiomyocytes showed elevated NRF2 expression. Small-interfering RNA-mediated silencing of NRF2 expression in cardiomyocytes resulted in the inhibition of the protective effects of CTRP12. Thus, CTRP12 ameliorated injury in LPS-stimulated cardiomyocytes in an NRF2-dependent manner.

The potassium channel KCa3.1 promotes cell proliferation by activating SKP2 and metastasis through the EMT pathway in hepatocellular carcinoma.

The intermediate conductance calcium-activated potassium channel (KCa3.1) plays an important role in maintaining intracellular calcium homeostasis and is involved in the tumorigenesis of many human cancers. However, it is unknown whether KCa3.1 plays a role in the genesis of hepatocellular carcinoma (HCC), one of the most common malignant tumors worldwide with a very poor prognosis. In our study, we found that the expression of KCa3.1 was significantly elevated in poorly differentiated HCC tissues compared to adjacent noncancerous tissues. In vitro and in vivo experiments showed that KCa3.1 could promote cell proliferation, migration, and invasion of HCC. Mechanistically, KCa3.1 promoted cell cycle progression and migration and invasion of HCC cells by activating S-phase protein kinase 2 (SKP2) to trigger the degradation of p21 and p27 and targeting Reelin (RELN) to induce epithelial-mesenchymal transition (EMT), respectively. Taken together, our results demonstrate that KCa3.1 plays an important role in the genesis and progression of HCC, implying that it might be a promising therapeutic target in HCC.

Dihydromyricetin protects against lipopolysaccharide­induced cardiomyocyte injury through the toll­like receptor­4/nuclear factor­κB pathway.

Dihydromyricetin (DHM) is a bioactive flavonoid compound extracted from the stems and leaves of Ampelopsis grossedentata. Previous studies have indicated that DHM has antioxidation and antitumor capabilities, while the effect of DHM on lipopolysaccharide (LPS)­induced cardiomyocyte injury has not been clarified. Therefore, the aim of the present study was to investigate the effect of DHM on LPS­induced cardiomyocyte injury. In the present study, cardiomyocytes were randomized to the control (PBS), LPS and DHM + LPS groups. The LPS group was treated with 10 µg/ml LPS for 12 h and the DHM + LPS group was treated with 100 or 25 µM DHM 12 h prior to treatment with LPS. The protective effect of DHM on LPS­induced cardiomyocytes injury was evaluated by Cell Counting kit­8 assay, TUNEL staining, reverse transcription­quantitative polymerase chain reaction and western blot analysis. The results demonstrated that LPS treatment led to cardiomyocyte apoptosis, and these effects were significantly attenuated by DHM. Furthermore, LPS treatment downregulated the expression of B­cell lymphoma 2 apoptosis regulator (Bcl­2) and induced increased expression of Bcl­2­associated X apoptosis regulator (Bax). Additionally, DHM treatment reversed LPS­induced changes in Bcl­2 expression and Bax expression in cardiomyocytes, and rescued cells from apoptosis. In addition, increased mRNA expression levels of tumor necrosis factor­α and interleukin­6 induced by LPS were attenuated following treatment with DHM. Further investigation demonstrated that DHM suppressed the activation of toll­like receptor­4 (TLR4), which is involved in regulating the downstream signaling pathway of nuclear factor­κB (NF­κB). DHM attenuated LPS­induced cardiomyocyte injury, the potential mechanism responsible for this effect may involve inhibition of TLR4 activation and subsequent regulation of the associated downstream signaling pathway of NF­κB. The current study indicates that DHM may protect cardiomyocytes against LPS­induced injury by inhibition of the TLR4/NF­κB signaling pathway. The results of the present study may provide support for the development DHM as a strategy for the treatment of heart failure in septic shock.

Syringin prevents cardiac hypertrophy induced by pressure overload through the attenuation of autophagy.

Syringin, extracted from Eleutherococcus senticosus, is a major biologically active component of Chinese herbs. Studies have certified the multiple pharmacological properties of syringin. However, the role of syringin in cardiac hypertrophy and the mechanisms involved remain unclear. In this study, aortic banding was performed on mice in order to induce cardiac hypertrophy, and the animals were then treated with syringin for 7 weeks. Echocardiography and catheter-based measurements of hemodynamic parameters were performed to evaluate cardiac function at 8 weeks following aortic banding. Morphological and pathological changes were also evaluated. Alterations in the expression levels of hypertrophy- and autophagy-related markers [atrial natriuretic peptide (ANP), ß-myosin heavy chain MHC), α-MHC, B-type natriuretic peptide (BNP), autophagy-related gene (ATG)5, ATG7, beclin 1, light chain 3 (LC3) A/B] were measured by reverse transcription-quantitative PCR and western blot analysis. The effects of syringin on cardiomyocyte hypertrophy induced by angiotensin II in H9c2 cells were also investigated. The results revealed that syringin attenuated cardiac hypertrophy induced by aortic banding via the activation of AMP-activated protein kinase α (AMPKα) and autophagy-related signaling pathways. Thus, we our data suggest that syringin possesses therapeutic potential to attenuate the progression of cardiac hypertrophy.

Puerarin attenuates the inflammatory response and apoptosis in LPS-stimulated cardiomyocytes.

Patients with septic shock suffer from high mortality rates, particularly when complicated by severe myocardial depression which is characterized by hypotension and a reduction in cardiac output. Inflammation is an important factor involved in the early stages of sepsis. The aim of the present study was to investigate the effect of the Chinese herbal compound puerarin (1, 5, 10, 20 and 40 µM) on cardiomyocyte inflammatory response in a sepsis model using H9c2 cardiomyocytes stimulated with 1 µg/ml lipopolysaccharide (LPS). The mRNA expression levels of tumor necrosis factor (TNF)-α and interleukin (IL)-ß were evaluated using reverse transcription-quantitative polymerase chain reaction. In addition, the protein expression levels of various factors were determined using western blot analysis. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was used to evaluate the apoptosis rates in the various groups, and immunocytochemical analysis was employed to determine the effect of puerarin on the nuclear translocation of p65 protein. The present study demonstrated that LPS stimulation increased IL-1ß and TNF-α mRNA expression levels, as compared with the controls (P<0.05). Following treatment with various concentrations of puerarin, the expression levels of IL-1ß and TNF-α were markedly blunted, particularly in the LPS + 40 µM puerarin group (P<0.05 vs. the LPS group). Furthermore, puerarin administration significantly inhibited LPS-induced apoptosis in H9c2 cardiomyocytes, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining (TUNEL positive cells: LPS + 40 µM puerarin group, 5.5% vs. LPS group, 10.5%; P<0.01). In addition, puerarin significantly decreased LPS-induced phosphorylated nuclear factor (p-NF)-κB p65 and Bax expression levels, and increased the expression levels of Bcl-2, as compared with the LPS group (P<0.05). These data indicated that puerarin may serve as a valuable protective agent against cardiovascular inflammatory diseases.

Shensongyangxin protects against pressure overload­induced cardiac hypertrophy.

Shensongyangxin (SSYX) is a medicinal herb, which has long been used in traditional Chinese medicine. Various pharmacological activities of SSYX have been identified. However, the role of SSYX in cardiac hypertrophy remains to be fully elucidated. In present study, aortic banding (AB) was performed to induce cardiac hypertrophy in mice. SSYX (520 mg/kg) was administered by daily gavage between 1 and 8 weeks following surgery. The extent of cardiac hypertrophy was then evaluated by pathological and molecular analyses of heart tissue samples. In addition, in vitro experiments were performed to confirm the in vivo results. The data of the present study demonstrated that SSYX prevented the cardiac hypertrophy and fibrosis induced by AB, as assessed by measurements of heart weight and gross heart size, hematoxylin and eosin staining, cross­sectional cardiomyocyte area and the mRNA expression levels of hypertrophic markers. SSYX also inhibited collagen deposition and suppressed the expression of transforming growth factor ß (TGFß), connective tissue growth factor, fibronectin, collagen Ⅰα and collagen Ⅲα, which was mediated by the inhibition of the TGFß/small mothers against decapentaplegic (Smad) signaling pathway. The inhibitory action of SSYX on cardiac hypertrophy was mediated by the inhibition of Akt signaling. In vitro investigations in the rat H9c2 cardiac cells also demonstrated that SSYX attenuated angiotensin II­induced cardiomyocyte hypertrophy. These findings suggested that SSYX attenuated cardiac hypertrophy and fibrosis in the pressure overloaded mouse heart. Therefore, the cardioprotective effect of SSYX is associated with inhibition of the Akt and TGFß/Smad signaling pathways.

Naringenin attenuates pressure overload-induced cardiac hypertrophy.

Cardiac hypertrophy is characterized by abnormal enlargement of cardiomyocytes and disproportionate accumulation of extracellular interstitial fibrosis, which are major predictors of the development of coronary artery disease and heart failure. Naringenin is a bitter principle component of grapefruit that has numerous pharmacological effects, including anti-inflammatory, hypolipidemic, antithrombotic and antiatherogenic properties. In order to investigate whether naringenin is able to exert a protective effect against cardiac hypertrophy induced by pressure overload, aortic banding (AB) was performed to induce cardiac hypertrophy in mice, and naringenin was administered for 7 weeks. A total of 60 mice were allocated into four groups: Sham + vehicle, AB + vehicle, sham + naringenin and AB + naringenin. Naringenin treatment attenuated cardiac dysfunction, as indicated by the results of echocardiography and catheter-based measurements at 8 weeks post-surgery. The extent of cardiac hypertrophy was assessed by the heart weight/body weight, heart weight/tibial length and lung weight/body weight ratios, in addition to the cardiomyocyte cross-sectional area and the mRNA expression levels of hypertrophic maker, all of which were mitigated by naringenin administration. Naringenin also inhibited the expression of transforming growth factor-ß1, connective tissue growth factor, collagen Iα and collagen IIIα, and attenuated interstitial fibrosis. In addition, naringenin downregulated the activation of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathways. In conclusion, naringenin attenuated cardiac hypertrophy and interstitial fibrosis, in addition to improving left ventricular function in pressure-overloaded mice. The cardioprotective effect exerted by naringenin may be associated with the inhibition of PI3K/Akt, ERK and JNK signaling pathways.

Pachymic acid protects H9c2 cardiomyocytes from lipopolysaccharide-induced inflammation and apoptosis by inhibiting the extracellular signal-regulated kinase 1/2 and p38 pathways.

Pachymic acid (PA), a lanostane-type triterpenoid and the major component of Poria cocos alcoholic extracts, has various pharmacological effects, including anti-inflammatory, anti-oxidative and anti-apoptotic. However, few studies have investigated the effects of PA on lipopolysaccharide (LPS)-induced H9c2 cell apoptosis and inflammation, or identified the possible mechanisms underlying these effects. In the present study, H9c2 cardiomyocytes were stimulated by LPS and treated with or without PA. The increased mRNA expression levels of tumor necrosis factor-α, interleukin (IL)-1 and IL-6 induced by LPS were attenuated following treatment with PA. PA also attenuated LPS-induced apoptosis, as determined by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and regulated the LPS-induced protein expression levels of caspase 3, 8 and 9. Furthermore, the phosphorylations of extracellular-regulated kinase (Erk)1/2 and p38 in the LPS-treated H9c2 cells were inhibited by PA. These results suggested that treatment with PA prevented the LPS-induced inflammatory and apoptotic response in cardiomyocytes, which may be mediated by inhibition of the Erk1/2 and p38 pathways.

Cathepsin B deficiency attenuates cardiac remodeling in response to pressure overload via TNF-α/ASK1/JNK pathway.

Cathepsin B (CTSB), a member of the lysosomal cathepsin family that is expressed in both murine and human hearts, was previously shown to participate in apoptosis, autophagy, and the progression of certain types of cancers. Recently, CTSB has been linked to myocardial infarction. Given that cathepsin L, another member of the lysosomal cathepsin family, ameliorates pathological cardiac hypertrophy, we hypothesized that CTSB plays a role in pressure overload-induced cardiac remodeling. Here we report that CTSB was upregulated in cardiomyocytes in response to hypertrophic stimuli both in vivo and in vitro. Moreover, knockout of CTSB attenuated pressure overload-induced cardiac hypertrophy, fibrosis, dysfunction, and apoptosis. Furthermore, the aortic banding-induced activation of TNF-α, apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinases (JNK), c-Jun, and release of cytochrome c was blunted by CTSB deficiency, which was further confirmed in in vitro studies induced by angiotensin II. In cardiomyocytes pretreatment with SP600125, a JNK inhibitor, suppressed the cardiomyocytes hypertrophy by inhibiting the ASK1/JNK pathway. Altogether, these data indicate that the CTSB protein functions as a necessary modulator of hypertrophic response by regulating TNF-α/ASK1/JNK signaling pathway involved in cardiac remodeling.