Drug-containing serum of rhubarb-astragalus capsule inhibits the epithelial-mesenchymal transformation of HK-2 by downregulating TGF-ß1/p38MAPK/Smad2/3 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum palmatum L; Astragalus membranaceus (Fisch.), is referred to as 'Dahuang, Huangqi' in China. As an important medicinal plant, the rhizome of rhubarb and astragalus is traditionally used in the treatment of kidney diseases associated with renal failure, inflammation and tumors. AIM OF THE STUDY: This study aimed to investigate the effect of a drug-containing serum of rhubarb-astragalus capsules (composed of rhubarb and astragalus) and to elucidate its mechanism in the epithelial-mesenchymal transformation of renal tubular epithelial cells. MATERIALS AND METHODS: Epithelial-mesenchymal transformation (EMT) of HK-2 cells was induced by TGF-ß1, and rhubarb-astragalus and losartan drug-containing serum from rats, as well as SB203580 (a specific inhibitor of p38 MAPK), were used. High-performance liquid chromatography analysis was performed to determine the main components of the drug-containing serum of rhubarb-astragalus from rats. Western blotting and immunofluorescence analysis were used to determine the levels of protein expression, and real-time quantitative PCR analysis was used to detect the levels of gene expression. RESULTS: The drug-containing serum of rhubarb-astragalus contained emodin (0.36 µg/ml) and danthraquinone (0.96 µg/ml). Rhubarb-astragalus significantly decreased the protein expression levels of α-SMA, FN, vimentin and N-cadherin in HK-2 cells that were increased by TGF-ß1, while it significantly increased the E-cadherin protein expression level that was decreased by TGF-ß1. Rhubarb-astragalus also significantly decreased the protein expression levels of TGF-ß1 and p38 MAPK and the mRNA expression levels of α-SMA, vimentin, TGF-ß1, p38 MAPK, Smad2 and Smad3 in HK-2 cells that were increased by TGF-ß1. It is worth noting that SB203580 (a p38 MAPK inhibitor) had similar effects as rhubarb-astragalus in this study. CONCLUSION: The drug-containing serum of rhubarb-astragalus can inhibit EMT in HK-2 cells by downregulating the TGF-ß1/p38 MAPK/Smad2/3 pathway.

Qiliqiangxin attenuates atrial structural remodeling in prolonged pacing-induced atrial fibrillation in rabbits.

Qiliqiangxin (QL) can attenuate myocardial remodeling and improve cardiac function in some cardiac diseases, including heart failure and hypertension. This study was to explore the effects and mechanism of QL on atrial structural remodeling in atrial fibrillation (AF). Twenty-one rabbits were randomly divided into a sham-operation group, pacing group (pacing with 600 beats per minute for 4 weeks), and treatment group (2.5 g/kg/day). Before pacing, the rabbits received QL-administered p.o. for 1 week. We measured atrial electrophysiological parameters in all groups to evaluate AF inducibility and the atrial effective refractory period (AERP). Echocardiography evaluated cardiac function and structure. TUNEL detection, hematoxylin and eosin (HE) staining, and Masson's trichrome staining were performed. Immunohistochemistry and western blotting (WB) were used to detect alterations in calcium channel L-type dihydropyridine receptor α2 subunit (DHPR) and fibrosis-related regulatory factors. AF inducibility was markedly decreased after QL treatment. Furthermore, we found that AERP and DHPR were reduced significantly in pacing rabbits compared with sham rabbits; treatment with QL increased DHPR and AERP compared to the pacing group. The QL group showed significantly decreased mast cell density and improved atrial ejection fraction values compared with the pacing group. Moreover, QL decreased interventricular septum thickness (IVSd) and left ventricular end-diastolic diameter (LVEDD). Compared with the sham group, the levels of TGFß1 and P-smad2/3 were significantly upregulated in the pacing group. QL reduced TGF-ß1 and P-smad2/3 levels and downstream fibrosis-related factors. Our study demonstrated that QL treatment attenuates atrial structural remodeling potentially by inhibiting TGF-ß1/P-smad2/3 signaling pathway.

Chalcone flavokawain A attenuates TGF-ß1-induced fibrotic pathology via inhibition of ROS/Smad3 signaling pathways and induction of Nrf2/ARE-mediated antioxidant genes in vascular smooth muscle cells.

TGF-ß1 plays a crucial role in the pathogenesis of vascular fibrotic diseases. Chalcones are reportedly cancer chemo-preventive food components that are rich in fruits and vegetables. In this study, flavokawain A (FKA, 2-30 µM), a naturally occurring chalcone in kava extracts, was evaluated for its anti-fibrotic and antioxidant properties in TGF-ß1-stimulated vascular smooth muscle (A7r5) cells, as well as its underlying molecular mechanism of action. Immunofluorescence data showed down-regulated F-actin expression with FKA treatment in TGF-ß1-stimulated A7r5 cells. Western blotting demonstrated that FKA treatment suppressed the expression of α-SMA and fibronectin proteins under TGF-ß1 stimulation. Findings from wound-healing and invasion experiments showed that FKA inhibits TGF-ß1-mediated migration and invasion. Western blotting demonstrated that treatment with FKA down-regulated MMP-9 and MMP-2 and up-regulated TIMP-1 expression. Further evidence showed that FKA decreased TGF-ß1-mediated phosphorylation and the transcriptional activity of Smad3. TGF-ß1-induced excessive ROS production was remarkably reversed by FKA treatment in A7r5 cells, and inhibition by FKA or N-acetylcysteine (NAC) substantially diminished TGF-ß1-induced p-Smad3 activation and wound-healing migration. Interestingly, FKA-mediated antioxidant properties were associated with increased nuclear translocation of Nrf2 and elevated antioxidant response element (ARE) luciferase activity. Activation of Nrf2/ARE signaling was accompanied by the induction of HO-1, NQO-1 and γ-GCLC genes in FKA-treated A7r5 cells. Notably, silencing of Nrf2 (siRNA transfection) significantly diminished the FKA-mediated antioxidant effects, indicating that FKA may inhibit TGF-ß1-induced fibrosis through suppressing ROS generation in A7r5 cells. Our results suggested that anti-fibrotic and antioxidant activities of the chalcone flavokawain A may contribute to the development of food-based chemo-preventive drugs for fibrotic diseases.

SS1P Immunotoxin Induces Markers of Immunogenic Cell Death and Enhances the Effect of the CTLA-4 Blockade in AE17M Mouse Mesothelioma Tumors.

SS1P is an anti-mesothelin immunotoxin composed of a targeting antibody fragment genetically fused to a truncated fragment of Pseudomonas exotoxin A. Delayed responses reported in mesothelioma patients receiving SS1P suggest that anti-tumor immunity is induced. The goal of this study is to evaluate if SS1P therapy renders mesothelioma tumors more sensitive to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) immune checkpoint blockade. We evaluated the ability of SS1P to induce adenosine triphosphate (ATP) secretion and calreticulin expression on the surface of AE17M mouse mesothelioma cells. Both properties are associated with immunogenic cell death. Furthermore, we treated these tumors with intra-tumoral SS1P and systemic CTLA-4. We found that SS1P increased the release of ATP from AE17M cells in a dose and time-dependent manner. In addition, SS1P induced calreticulin expression on the surface of AE17M cells. These results suggest that SS1P promotes immunogenic cell death and could sensitize tumors to anti-CTLA-4 based therapy. In mouse studies, we found that the combination of anti-CTLA-4 with intra-tumoral SS1P induced complete regressions in most mice and provided a statistically significant survival benefit compared to monotherapy. The surviving mice were protected from tumor re-challenge, indicating the development of anti-tumor immunity. These findings support the use of intra-tumoral SS1P in combination with anti-CTLA-4.

Synthesis and discovery of a drug candidate for treatment of idiopathic pulmonary fibrosis through inhibition of TGF-ß1 pathway.

In this study, anti-IPF lead compounds 42 and 44, derived from natural sesquiterpene lactones Isoalantolactone and alantolactone, were discovered by screening from a high-throughput TGF-ß1 reporter luciferase assay. Notably, they could reduce the myofibroblast activation and extracellular matrix deposition both in vitro and in vivo. Additionally, compounds 42 and 44 could significantly attenuate bleomycin-induced pulmonary fibrosis in mice. Further validation of pharmacokinetics study and toxicity evaluation indicated that compound 44 might be a promising anti-IPF drug candidate.

Novel Antibody Therapeutics Targeting Mesothelin In Solid Tumors.

ABSTRACT BACKGROUND: Monoclonal antibodies have become attractive clinical anti-cancer drugs in the last 3 decades due to their targeting specificity and suitable pharmacokinetic properties. Mesothelin is a tumor-associated antigen with limited expression in normal tissues. It is frequently over-expressed on the cell membrane of a number of epithelial malignancies (e.g. mesothelioma, pancreatic, ovarian, lung, triple negative breast and gastric cancers). METHODS: Mesothelin is validated as a suitable antibody target for cancer therapy. A number of novel antibody therapeutics targeting mesothelin in development are compared and their mechanisms of action are also discussed. Both basic science and clinical data are provided to give a complete veiw of how an agent is developed from bench to bedside. RESULTS: Novel antibody therapeutics, including unconjugated monoclonal antibodies, recombinant immunotoxins and antibody-drug conjugates, targeting mesothelin exert anti-tumor activities by different mechanisms of action. Based on the convincing preclinical data generated with these molecules, the antibody therapeutics have been brought into early clinical evaluation where initial promising results were obtained. CONCLUSION: These antibody therapeutics directed against mesothelin are expected to have different safety profiles, based on their different mechanism of action. Further clinical development will reveal which of these molecules shows the best efficacy and widest therapeutic window and thus is best suited to bring benefit to the patients.

Phase 1 study of the antimesothelin immunotoxin SS1P in combination with pemetrexed and cisplatin for front-line therapy of pleural mesothelioma and correlation of tumor response with serum mesothelin, megakaryocyte potentiating factor, and cancer antigen 125.

BACKGROUND: The primary objective of this study was to determine the safety and maximum tolerated dose (MTD) of the antimesothelin immunotoxin SS1(dsFv)PE38 (SS1P) (a recombinant antimesothelin immunotoxin consisting of a murine antimesothelin variable antibody fragment [Fv] linked to PE38, a truncated portion of Pseudomonas exotoxin A) in combination with pemetrexed and cisplatin in chemotherapy-naive patients with advanced malignant pleural mesothelioma (MPM). Secondary objectives included tumor response, SS1P pharmacokinetics, and serum biomarkers of response. METHODS: Chemotherapy-naive patients with stage III or IV, unresectable, epithelial or biphasic MPM and normal organ functions were eligible. Pemetrexed (500 mg/m(2) on day 1) and cisplatin (75 mg/m(2) on day 1) were administered every 3 weeks for up to 6 cycles with escalating doses of SS1P administered intravenously on days 1, 3, and 5 during cycles 1 and 2. Tumor response was evaluated every 6 weeks. RESULTS: Twenty-four patients received SS1P at 4 dose levels from 25 to 55 mcg/kg. Grade 3 fatigue was dose-limiting in 1 patient at 55 mcg/kg. The MTD of SS1P was established as 45 mcg/kg. Other grade 3 toxicities associated with SS1P included hypoalbuminemia (21%), back pain (13%), and hypotension (8%). Of 20 evaluable patients, 12 (60%) had a partial response, 3 had stable disease, and 5 had progressive disease. Of 13 patients who received the MTD, 10 (77%) had a partial response, 1 had stable disease, and 2 had progressive disease. Objective radiologic responses were associated with significant decreases in serum mesothelin (P=.0030), megakaryocyte potentiating factor (P=.0005), and cancer antigen 125 (P < .0001). CONCLUSIONS: SS1P given with pemetrexed and cisplatin is safe and well tolerated and exhibits significant antitumor activity in patients with unresectable, advanced pleural mesothelioma. Serum mesothelin, megakaryocyte potentiating factor, and cancer antigen 125 levels correlated with objective tumor responses.

Role of TGF-ß1/p38 MAPK pathway in hepatitis B virus-induced tubular epithelial-myofibroblast transdifferentiation.

OBJECTIVE: This study is to investigate the hepatitis B virus (HBV)-induced tubular epithelial-myofibroblast transdifferentiation (TEMT) in human renal tubular epithelial HK-2 cells. METHODS: Human proximal tubular epithelial HK-2 cells were cultured. These HK-2 cells were divided into 4 groups: the blank control group, the vector control group, the HBV-transfected group, and the inhibitor-treated group. Transfection was performed with lipofectamine. Measurements of hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) in culture supernatant were determined by electrochemiluminescence immunoassay. Immunocytochemical staining, reverse transcription PCR (RT-PCR), and Western blot analysis were performed to detect the mRNA and protein expression levels, respectively. RESULTS: The immunocytochemical staining showed that, the expression level of E-cadherin was dramatically decreased, while the α-SMA expression level was significantly elevated, in HBV-transfected HK-2 cells. The mRNA level of TGF-ß1 and the protein level of p-p38 mitogen-activated protein kinase (MAPK) were elevated in HK-2 cells transfected with HBV. When treated with the p38 MAPK-specific inhibitor, the activation of p38 MAPK was eliminated in HBV-transfected HK-2 cells. In addition, the altered expression levels of E-cadherin and α-SMA, the increased contents of HBeAg and HBsAg in the culture supernatant, as well as the morphological changes of TEMT in HBV-transfected HK-2 cells, were all reversed by the inhibiter treatment. CONCLUSION: HBV transfection could induce TEMT in HK-2 cells, which was mediated by the TGF-ß1/p38 MAPK pathway. These findings provide new insights into the prevention and treatment of HBV-associated glomerulonephritis.

Mesothelin as a potential therapeutic target in human cholangiocarcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the two most common primary liver cancers, yet there have been no significant advances in effective therapeutics. Mesothelin has been reported as a new therapeutic target in various types of cancer. Here, we investigated the expression of mesothelin in liver cancer and its potential role as a novel therapeutic target for immunotherapy. METHODS: HCC and CCA specimens were examined by immunohistochemistry for mesothelin expression. Protein expression was assessed by immunoblotting and flow cytometry. The SS1P immunotoxin targeting mesothelin was evaluated in the well-established CCA cell lines HuCCT1, HuH-28, KMBC, KMCH, Mz-ChA-1 and OZ. RESULTS: We showed strong immunochemical mesothelin staining in 33% of the surgically resected CCA specimens and 3 of 6 CCA cell lines (OZ, KMBC and KMCH). No mesothelin staining was found in HCC or normal liver tissue. Mesothelin was primarily localized to the cellular plasma membrane and the mature form (molecular weight, ~40 kDa) was expressed at a high level in CCA tissues. Moreover, 22% of CCA specimens had a high mesothelin expression level which was comparable to the CCA cell line models. Interestingly, SS1P showed very high and specific growth inhibition when added to mesothelin-expressing CCA cells with IC(50) values ranging from 0.5 to 11 ng/mL. CONCLUSIONS: Mesothelin is overexpressed in one-third of CCA tissues. SS1P targeting mesothelin reveals a remarkable single agent activity against CCA in vitro. These findings indicate a potential for SS1P in the immunotherapeutic treatment of CCA.