n Li

Analysis of urinary metabolic profile in aging rats undergoing caloric restriction

Background and aims: While caloric restriction (CR) is associated with a prolonged lifespan in multiple species by regulating metabolism, a comprehensive profile of metabolism under CR conditions remains largely unclear. Therefore, in this study we aimed to characterize the metabolomic profiling associated with CR using a rat model. Methods: Rapid resolution liquid chromatography/electrospray ionization quadrupole-time of flight mass spectrometry (RRLC/ESI-Q-TOFMS) was employed to analyze metabolomic profiling of urine samples from aging rats who underwent caloric restriction (CR; n=7) or were provided a normal diet (N; n=8) for 12 weeks time. Multivariate data analysis was performed on the mass data of metabolomic profiles to uncover the differences between the CR and N groups. Results: CR treatment led to manifest metabolic changes in aging rats, and fifteen urinary metabolites including hypoxanthine, hippurate, dimethylglycine and creatinine were significantly different in the rat groups. Conclusion: Our study demonstrates the high reliability of the HPLC-based metabolomic approach towards the study of anti-aging effects induced by CR, while the urinary metabolites we identified may become potential biomarkers of aging.

Antitumor Activity of a New N-Substituted Thiourea Derivative, an EGFR Signaling-Targeted Inhibitor against a Panel of Human Lung Cancer Cell Lines

Epidermal growth factor receptor (EGFR) is one of the important protein tyrosine kinases (PTKs), whose blockade by tyrosine kinase inhibitors (TKIs) has been introduced in the treatment of advanced non-small-cell lung cancers (NSCLCs). However, intrinsic and acquired resistance to the clinically used erlotinib or gefitinib leads to poor overall prognosis. The novel EGFR-TKI will provide alternative choices in NSCLC treatment and might be beneficial. We have previously reported the design and synthesis of a novel class of PTK inhibitors featuring the N-(2-oxo-1,2-dihydro-quinolin-3-ylmethyl)-thiourea framework. In this study, we examined the antitumor effect of compound 5a (DC27) in a panel of human lung carcinoma cell lines. The results of a bromodeoxyurdine (BrdU) incorporation assay revealed that cell proliferation was inhibited in a dose-dependent manner, with an IC50 of 2.5–12.9 µM, similar to gefitinib (1.1–15.6 µM). DC27 induced G₀/G1 arrest of cell cycle and apoptosis as tested by flow cytometry. DC27 markedly reduced tyrosine phosphorylation of EGFR and inhibited activation of Erk1/2 and AKT, two key downstream effectors of proliferation. In conclusion, DC27 has potent in vitro cytotoxicity against human lung carcinoma cells, possibly mediated by induction of apoptosis and cell cycle arrest in G₀/G1 phase.

Clinical characteristics and disease predictors of a large Chinese cohort of patients with autosomal dominant polycystic kidney disease

Objective Autosomal dominant polycystic kidney disease (ADPKD) is a relentlessly progressing form of chronic kidney disease for which there is no cure. The aim of this study was to characterize Chinese patients with ADPKD and to identify the factors which predict cyst growth and renal functional deterioration. Methods To analyze disease predicting factors we performed a prospective longitudinal observational study in a cohort of 541 Chinese patients with ADPKD and an eGFR ≥30 ml/min/1.73 m2. Patients were followed clinically and radiologically with sequential abdominal magnetic resonance imaging (MRI). Clinical characteristics and laboratory data were related to changes in estimated glomerular filtration rate (eGFR) and total kidney volume (TKV). A linear regression model was developed to analyze the factors which determine eGFR and TKV changes. Results The age range of this unselected cohort ranged from 4 to 77 years. Median follow-up time was 14.3±10.6 months. Although inter-individual differences in eGFR and TKV were large, there was a consistent link between these two parameters. Baseline log10-transformed TKV and urinary protein/creatinine ratio were identified as the major predictors for a faster eGFR decline and were associated with a higher TKV growth rate. Interestingly, a lower thrombocyte count correlated significantly with lower eGFR (r = 0.222) and higher TKV (r = 0.134). Conclusions This large cohort of Chinese patients with ADPKD provides unique epidemiological data for comparison with other cohorts of different ethnicity. In Chinese patients we identified a lower thrombocyte count as a significant predictor of disease progression. These results are important for the design of future clinical trials to retard polycystic kidney disease progression.

Olmesartan Prevents Microalbuminuria in db/db Diabetic Mice Through Inhibition of Angiotensin II/p38/SIRT1-Induced Podocyte Apoptosis

Background/Aims: Blockage of the renin-angiotensin II system (RAS) prevents or delays albuminuria in diabetic patients. The aim of this study was to investigate the inhibitory mechanism of the angiotensin receptor blocker olmesartan on albuminuria in a murine model of diabetic nephropathy. Methods: Male db/db diabetic mice were fed with placebo or 20 mg/kg olmesartan by daily gavage for 12 weeks. Conditionally immortalized mouse podocytes were treated with glucose, angiotensin II, olmesartan or p38 inhibitor s8307 in different experimental conditions after differentiation. Results: Olmesartan reduced albuminuria in db/db mice without change in body weight and glycemia. The increase of apoptotic cells and decrease of podocytes in the diabetic glomerulus were prevented by olmesartan. Moreover, olmesartan restored silent mating type information regulation 1 (SIRT1) expression in diabetic glomeruli. Furthermore, olmesartan treatment suppressed p38 phosphorylation but did not restore adenosine 5‘-monophosphate-activated protein kinase (AMPK) phosphorylation in the diabetic glomerulus. In vitro study revealed that olmesartan prevented angiotensin II/p38/SIRT1 induced podocyte apoptosis, but it only slightly prevented high glucose/AMPK/SIRT1 induced podocyte apoptosis. In addition, the p38 inhibitor s8307 reversed SIRT1 expression and angiotensin II induced podocyte apoptosis. Conclusions: Olmesartan reduced albuminuria in diabetic nephropathy through inhibiting angiotensin II/p38/SIRT1 triggered podocyte apoptosis.

B5, a novel pyrrole-substituted indolinone, exerts potent antitumor efficacy through G2/M cell cycle arrest

Summary(E)-Ethyl 3,5-dimethyl-4-[(indolin-2-one-3-ylidene)methyl]-1H-pyrrole-2-carboxylate (B5) was one of the novel pyrrole-substituted indolinones synthesized in our research with the initial aim of developing selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKIs). However, B5 exhibited weak inhibitory potency against a variety of protein tyrosine kinases including EGFR, but potent kinase inhibition against several members of the cyclin-dependent kinase (CDK) family. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay demonstrated that B5 had approximately 500 times more potent antitumor activity than PD153035, a known standard EGFR-TKI, in a panel of ten epithelial cancer cell lines. B5 did not inhibit the phosphorylation of EGFR induced by EGF in vitro. DNA flow cytometric analysis revealed that B5 induced cell cycle arrest at G2/M phase and western blot analysis indicated that both CDK1 (Cdc2) and cyclin B1 proteins were decreased after B5 treatment. Our findings suggested the potential therapeutic applications of B5 in numerous cancers and a promising new template for further development of antitumor agents.

Antitumor efficacy of two novel non-thiazolidinedione compounds as peroxisome proliferator-activated receptor-gamma agonists in human osteosarcoma cells in vitro.

Background: Due to chemotherapy resistance in osteosarcoma subgroups, the prognosis of these patients is still poor, and the development of new agents is of utmost importance. The aim of our study was to test the antitumor effects of two novel α-aryloxy-α-methylhydrocinnamic acid derivatives as peroxisome proliferator-activated receptor (PPAR) γ agonists, together with rosiglitazone, a well-known thiazolidinedione (TZD) acting on several osteosarcoma cell lines. Methods/Results: The MTT assay revealed that cell viability was inhibited in a dose-dependent manner with IC50 6.2–15.8 μM for the two novel compounds and rosiglitazone (48.4–83.5 μM). Exposure to DG8 and DH9 at low micromolar concentrations induced a dose-dependent block of DNA synthesis and colony formation. In these antitumor assays, DG8 and DH9 were more effective than rosiglitazone, although the PPARγ agonistic activity of rosiglitazone is much higher. The SiRNA approach to downregulate specifically PPARγ in U-2OS cells did not affect the cytotoxic efficiency of either the two novel compounds or rosiglitazone. Conclusion: These observations suggest that non-TZDs with less PPARγ agonistic activity might show more potent antitumor efficacy independent of PPARγ in human osteosarcoma cells, which supports the possibility that they could be beneficial in the treatment of osteosarcoma patients.

Treatment of Persistent Gross Hematuria with Tranexamic Acid in Autosomal Dominant Polycystic Kidney Disease

Background/Aims: In this retrospective study we aimed to compare the effect of tranexamic acid (TXA) vs etamsylate, two hemostatic agents, on hematuria duration in autosomal dominant polycystic kidney disease (ADPKD) patients with persistent gross hematuria. Methods: This is a retrospective study of 40 patients with ADPKD and macroscopic hematuria. 20 patients receiving TXA and snake venom blood clotting enzyme injection were compared with 20 matched patients receiving etamsylate and snake venom blood clotting enzyme injection. The primary outcome was hematuria duration and the secondary outcomes were blood transfusion requirements and adverse events. Results: The hematuria duration was shorter in the TXA group compared with the etamsylate group (4[3-5] d vs 7[6-10] d, P<0.001). The volume of blood transfusion tended to be less in the TXA group than in the etamsylate group (300±115 ml vs 486±195 ml, P=0.12), and the number of patients needing a blood transfusion also tended to be lower [20% (4/20) vs 35% (7/20), P=0.29]. TXA and etamsylate were equally well tolerated and no serious adverse events were observed in both groups. Conclusions: Our study indicates that TXA treatment was more effective than etamsylate in stopping bleeding in ADPKD patients with persistent gross hematuria.

Triptolide delays disease progression in an adult rat model of polycystic kidney disease through the JAK2-STAT3 pathway

The aim of our current study was to investigate the long-term effect and the mechanism of triptolide in an adult nonorthologous rat model of polycystic kidney disease (PKD). Male wild-type (+/+) and Cy/+ cystic Han:SPRD rats were treated with vehicle or triptolide from 4 to 16 wk of age. Rats were killed at 16 wk of age for blood, urine, and organ collection. Human-derived WT9-12 PKD cells were treated with triptolide with or without IL-6 pretreatment. Cell proliferation, apoptosis, and cytotoxicity were determined. Western blotting and immunohistochemistry analysis were performed to evaluate the activation of IL-6-JAK2-STAT3 pathway. Renal function was protected by 12 wk of triptolide treatment in cystic Han:SPRD rats as shown by reduced blood urea nitrogen, serum creatinine, and proteinuria levels. Cyst and kidney growth were also retarded by triptolide treatment in Cy/+ rats. We further found that the proliferation index was reduced by triptolide in cystic rats, which was correlated with the reduced expression of IL-6/IL-6 receptor, decreased phosphorylation of JAK2-STAT3, and increased expression of suppressor of cytokine signaling 3 (SOCS3). The inhibitory effect of triptolide was further studied in WT9-12 cells. Triptolide inhibited cell proliferation and the activation of JAK2-STAT3 pathway in PKD cells, but it increased the expression of SOCS3. Pretreatment with IL-6 attenuated the inhibitory effect of triptolide on STAT3 phosphorylation. Our study revealed a long-term beneficial effect of triptolide in PKD that was probably through inhibition of the JAK2-STAT3 pathway.

Preferentially Expressed Antigen of Melanoma Prevents Lung Cancer Metastasis

Lung cancer is the most common cause of cancer death worldwide. The poor survival rate is largely due to the extensive local invasion and metastasis. However, the mechanisms underlying the invasion and metastasis of lung cancer cells remain largely elusive. In this study, we examined the role of preferentially expressed antigen of melanoma (PRAME) in lung cancer metastasis. Our results show that PRAME is downregulated in lung adenocarcinoma and lung bone metastasis compared with normal human lung. Knockdown of PRAME decreases the expression of E-Cadherin and promotes the proliferation, invasion, and metastasis of lung cancer cells by regulating multiple critical genes, most of which are related to cell migration, including MMP1, CCL2, CTGF, and PLAU. Clinical data analysis reveals that the expression of MMP1 correlates with the clinical features and outcome of lung adenocarcinoma. Taken together, our data demonstrate that PRAME plays a role in preventing the invasion and metastasis of lung adenocarcinoma and novel diagnostic or therapeutic strategies can be developed by targeting PRAME.