Evidence for a role of mitogen-activated protein kinases in the treatment of experimental acute pancreatitis

Acute pancreatitis(AP) is an inflammatory disease characterized by acute inflammation and necrosis of the pancreatic parenchyma. AP is often associated with organ failure, sepsis, and high mortality. The pathogenesis of AP is still not well understood. In recent years several papers have highlighted the cellular and molecular events of acute pancreatitis. Pancreatitis is initiated by activation of digestive enzymes within the acinar cells that are involved in autodigestion of the gland, followed by a massive infiltration of neutrophils and macrophages and release of inflammatory mediators, responsible for the local and systemic inflammatory response. The hallmark of AP is parenchymal cell necrosis that represents the cause of the high morbidity and mortality, so that new potential therapeutic approaches are indispensable for the treatment of patients at high risk of complications. However, not all factors that determine the onset and course of the disease have been explained. Aim of this article is to review the role of mitogen-activated protein kinases in pathogenesis of acute pancreatitis.

Interleukin-1 beta up-regulates tissue inhibitor of matrix metalloproteinase-1 mRNA and phosphorylation of c-jun N-terminal kinase and p38 in hepatic stellate cells

AIM： To study the relationship between interleukin-lbeta （IL-1β） up-regulating tissue inhibitor of matrix metalloproteinase-1 （TIMMP-1） mRNA expression and phosphorylation of both c-jun N-terminal kinase （INK） and p38 in rat heffatic stellate cells （HSC）. METHODS： RT-PCR was performed to measure the expression of TIMMP-1 mRNA in rat HSC. Western blot was performed to measure IL-1β-induced JNK and p38 activities in rat HSC. RESULTS： TIMMP-1 mRNA expression （1.191± 0.079） was much higher after treatment with IL-1β （10 ng/mL） for 24 h than in control group （0.545±0.091） （P〈0.01）. IL-1β activated INK and p38 in a time-dependent manner. After stimulation with IL-1β for 0, 5, 15, 30, 60 and 120 min, the INK activity was 0.982±0.299, 1.501±0.720, 2.133±0.882, 3.360±0.452, 2.181±0.789, and 1.385 ± 0.368, respectively. There was a significant difference in JNK activity at 15 min （P〈 0.01）, 30 min （P〈 0.01） and 60 min （P〈0.01） in comparison to that at 0 min. The p38 activity was 1.061±0.310, 2.050±0.863, 2.380±0.573, 2.973±0.953, 2.421±0.793, and 1.755 ± 0.433 at the 6 time points （0, 5, 15, 30, 60 and 120 min） respectively. There was a significant difference in p38 activity at 5 min （P〈0.05）, 15 min （P〈0.01）, 30 min （P〈0.01） and 60 min （P〈0.01） compared to that at 0 min. TIMMP-1 mRNA expression trended to decrease in 3 groups pretreated with different concentrations of SP600125 （10 μmol/L, 1.022±0.113; 20 μmol/L, 0.869±0.070; 40 μmol/L, 0.666±0.123）. Their decreases were all significant （P〈0.05, P〈0.01, P〈0.01） in comparison to control group （without SP600125 treatment, 1.163±0.107）. In the other 3 groups pretreated with different concentrations of SB203580 （10 μmol/L, 1.507±0.099; 20 μmol/L, 1.698±0.107; 40 μmol/L, 1.857±0.054）, the expression of TIMMP-1 mRNA increased. Their levels were higher than those in the control group （without SB203580 treatment, 1.027 ± 0.061） with a significant statistical significance （P〈 0.01）. CONCLUSION： IL-1β has a direct action on hepatic fibrosis by up-regulating TIMMP-1 mRNA expression in ratessionin in rate HSC.JNK and p38 mitogen-activated protein kinases （MAPKs） are involved in IL-1β-induced TIMMP-1 gene expression, and play a distinct role in this process, indicating that p38 and .INK pathways cooperatively mediate TIMP-1 mRNA expression in rat HSC.

Stress kinase inhibition modulates acute experimental pancreatitis

AIM: To examine the role of p38 during acute experimental cerulein pancreatitis. METHODS: Rats were treated with cerulein with or without a specific JNK inhibitor (CEP1347) and/or a specific p38 inhibitor (SB203580) and pancreatic stress kinase activity was determined. Parameters to assess pancreatitis included trypsin, amylase, lipase, pancreatic weight and histology. RESULTS: JNK inhibition with CEP1347 ameliorated pancreatitis, reducing pancreatic edema. In contrast, p38 inhibition with SB203580 aggravated pancreatitis with higher trypsin levels and, with induction of acinar necrosis not normally found after cerulein hyperstimulation. Simultaneous treatment with both CEP1347 and SB203580 mutually abolished the effects of either compound on cerulein pancreatitis. CONCLUSION: Stress kinases modulate pancreatitis differentially. JNK seems to promote pancreatitis development, possibly by supporting inflammatory reactions such as edema formation while its inhibition ameliorates pancreatitis. In contrast, p38 may help reduce organ destruction while inhibition of p38 during induction of cerulein pancreatitis leads to the occurrence of acinar necrosis.

Mitogen-activated protein kinase pathway inhibitors:inhibitors for diseases?

Mitogen-activated protein kinase(MAPK)signaling pathway,one of the most important signaling pathways in eukaryotic organism,is involved in multiple cellular events such as cell growth,differentiation,and apoptosis.MAPK is of great importance to the normal function of organisms,while its dysfunction results in various diseases.So far,inhibitors specifically against each subfamilies of MAP kinase have been developed,while more endeavors are needed to discover the compounds selectively targeting a particular subfamily member.Most of the kinase inhibitors exert their functions in an ATP-competitive way or a non-ATP-competitive way.Further studies on the effective mechanism of the MAPK inhibitors and their therapeutic roles in the treatment of diseases are helpful for the illumination of MAP kinase function,the development of novel inhibitors,and the therapy of diseases caused by the dysfunction of the MAPK pathway.

Stress-activated kinases as therapeutic targets in pancreatic cancer

Pancreatic cancer is a dismal disease with high incidence and poor survival rates.With the aim to improve overall survival of pancreatic cancer patients,new therapeutic approaches are urgently needed.Protein kinases are key regulatory players in basically all stages of development,maintaining physiologic functions but also being involved in pathogenic processes.c-Jun N-terminal kinases(JNK)and p38 kinases,representatives of the mitogen-activated protein kinases,as well as the casein kinase 1(CK1)family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors,DNA damage,and others.In their physiologic roles,they are responsible for the regulation of cell cycle progression,cell proliferation and differentiation,and apoptosis.Dysregulation of the underlying pathways consequently has been identified in various cancer types,including pancreatic cancer.Pharmacological targeting of those pathways has been the field of interest for several years.While success in earlier studies was limited due to lacking specificity and off-target effects,more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results.Consequently,targeting of JNK,p38,and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases.However,further studies are warranted,especially involving in vivo investigation and clinical trials,in order to advance inhibition of stress-activated kinases to the field of translational medicine.

Development of small molecule extracellular signal-regulated kinases(ERKs) inhibitors for cancer therapy

The mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase 1/2(ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.

Effects of U0126 on growth and activation of mitogen-activated protein kinases in Aspergillus fumigatus

Background Invasive aspergillosis （IA）, which is mainly caused by Aspergillus fumigatus （A. fumigatus）, is a major cause of morbidity and mortality in immunocompromised patients. Despite considerable progress in currently available antifungals the mortality still remains high in critically ill patients. U0126 which is a highly selective inhibitor of MEK1 and MEK2 in the RAF/MEK/ERK pathway in mammalian cells has been demonstrated to have an anti-proliferative role in cancer cells. The purpose of this study was to explore the role of U0126 on growth inhibition and activation of mitogen-activated protein kinases （MAPKs） in A. fumigatus. Methods Germination percentage and hyphae growth in A. fumigatus treated with U0126 were observed and compared with untreated controls. Western blotting analysis was used to detect changes in activation of SakA, MpkA and MpkB. Results U0126 inhibited germination and hyphae growth in A. fumigatus and enhanced the phosphorylation of SakA and MpkA under oxidative stress. U0126 at 10 pmol/L did not block the activation of MpkB during nitrogen starvation stress. Conclusion U0126 shows promise as an antifungal candidate and the MAPK pathway may be a possible antifungal drug target for A. fumigatus.

The involvement of p38 MAPK in transforming growth factor β1-induced apoptosis in murine hepatocytes

We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly inhibited the TGF-beta1-induced apoptosis and PAI-1 promoter activity. Treatment of cells with TGF-beta1 activates p38. Furthermore, over-expression of dominant negative mutant p38 also reduced the TGF-beta1-induced apoptosis. The data indicate that the activation of p38 is involved in TGF-beta1-mediated gene expression and apoptosis.

Sorafenib in breast cancer treatment:A systematic review and overview of clinical trials

AIM:To evaluate the current role of sorafenib,an oral multikinase inhibitor in the treatment of breast cancer.METHODS:An extensive search of the literature until March 2016 was carried out in Medline and clinicaltrials.gov,by using the search terms "sorafenib" and "breast cancer".Papers found were checked for further relevant publications.Overall,21 relevant studies were found,18 in advanced breast cancer(16 in stage Ⅳ and two in stages Ⅲ-Ⅳ) and three in early breast cancer.RESULTS:Among studies in advanced breast cancer,there were two trials with sorafenib as monotherapy,four trials of sorafenib in combination with taxanes,two in combination with capecitabine,one with gemcitabine and/or capecitabine,one with vinorelbine,one with bevacizumab,one with pemetrexed and one with ixabepilone,three trials of sorafenib in combination with endocrine therapy and two trials in women with brain metastases undergoing whole brain radiotherapy.In addition,there was one trial of sorafenib added to standard chemotherapy in the adjuvant setting,and two trials in the neoadjuvant setting.In general,sorafenib was well tolerated in breast cancer patients,though its dosage had to be adjusted in some trials,and discontinuation rates were high,particularly for the combination of sorafenib with anastrozole.Sorafenib monotherapy and combinations with taxanes,bevacizumab and ixabepilone showed inadequate efficacy,while efficacy results from combinations with gemcitabine and/or capecitabine and possibly tamoxifen were more promising.CONCLUSION:At present,sorafenib should not be used for the treatment of breast cancer outside of clinical trials and more clinical data are needed in order to support its standard use in breast cancer therapy.

Renoprotective Effect of Benazepril on Diabetic Nephropathy Mediated by P42/44MAPK

The effects of benazepril on P42/44MAPK, angiotensin Ⅱ expression in renal tissue and renal pathological change of the experimental diabetic rats were assessed and the possible mechanism of benazepril's renoprotective effect was explored. Adult male Wistar rats, 11—12 weeks age, weighing initially 160 to 200 g were randomly allocated into 2 groups: control group (A, n=6) and experimental group (n=12). Diabetic rats in experimental group were rendered diabetic by intraperitoneal injection of Streptozotocin (60 mg/kg body weight), and randomly subdivided into B group (diabetic control) and C group (diabetic rats treated with benazepril, 6 mg/kg every day). Studies were performed 8 weeks after induction of diabetes. Twenty-four h urine of every rat was collected to detect urine creatinine. Serum glucose concentration and serum creatinine were determined by collecting blood samples from the inferior vena cava. Body and kidney weight were recorded. Creatinine clearance (Ccr) and ratio of kidney weight to body weight were calculated. Plasma and renal tissue angiotensin Ⅱ concentration was assayed by radioimmunoassay (RIA). The phospo-p44/42MAPK protein expression was detected by Western-blot. The results showed that benazepril had no significant effect on the blood glucose level in diabetic rats in two experimental groups. Ccr and ratio of kidney weight to body weight were increased in group B (P<0.01) as compared with normal rats at the end of the 8th week. At the end of the 8th week, Ccr in group C was lower than that in group B (P<0.01). The ratio of kidney weight to body weight in group C was lower than that in group B at the 8th week. There were glomeruli hypertrophy and slight or moderate mesangium proliferation in diabetic rats, while there was fragmentally proliferative mesangium in group C at the end of the 8th week. Renal tissue angiotensin Ⅱ concentration was significantly increased in group B, while benazepril could significantly decrease the concentration of angiotensin Ⅱ in renal tissue. The expression of the phospo-p44/42MAPK protein in group B was increased as compared with group A, while it was decreased in group C as compared with group B. P42/44MAPK pathway participated in the pathogenesis of diabetic nephropathy. Benazepril can eliminate high filtration of glomeruli, decrease proteinuria, and eliminate renal hypertrophy as well as renal destruction. Renoprotective effect of benazepril in diabetic rats may be partly related to the inhibition of angiotensin Ⅱ-P42/44MAPK pathway.

Effects of an Engineered Anti-HER2 Antibody chA21 on Invasion of Human Ovarian Carcinoma Cell In Vitro

Objective： HER-2 plays an important role in the development and progression of ovarian carcinoma. A number of monoclonal antibodies （MAbs） and engineered antibody fragments （such as scFvs） against the subdomain II or IV of HER-2 extracellular domain （ECD） have been developed. We investigated the effect of chA21, an engineered anti-HER-2 antibody that bind primarily to subdomain I, on ovarian carcinoma cell invasion in vitro, and explored its possible mechanisms. Methods： Growth inhibition of SK-OV-3 cells was assessed using a Methyl thiazolyl tetrazolium （MTT） assay. The invasion ability of SK-OV-3 was determined by a Transwell invasion assay. The expression of matrix metalloproteinase-2 （MMP-2） and its tissue inhibitors （TIMP-2） was detected by immunocytochemical staining, and the expression of p38 and the phosphorylation of p38 were assayed by both immunocytochemistry and Western blot. Results： After treatment with chA21, the invasion of human ovarian cancer SK-OV-3 cells was inhibited in dose- and time-dependent manners. Simultaneously the expression of p38, phospho-p38, MMP-2 and the MMP-2/TIMP-2 ratio decreased, while TIMP-2 expression increased. Additionally, the decrease in phospho-p38 was much greater than that of p38. Conclusion： chA21 may inhibit SK-OV-3 cell invasion via the signal transduction pathway involving MMP-2, TIMP-2, p38 and the activation of p38MAPK.

Targeting ERK,an Achilles' Heel of the MAPK pathway,in cancer therapy

The mitogen-activated protein kinases(MAPK) pathway, often known as the RAS-RAFMEK-ERK signal cascade, functions to transmit upstream signals to its downstream effectors to regulate physiological process such as cell proliferation, differentiation, survival and death. As the most frequently mutated signaling pathway in human cancer, targeting the MAPK pathway has long been considered a promising strategy for cancer therapy. Substantial efforts in the past decades have led to the clinical success of BRAF and MEK inhibitors. However, the clinical benefits of these inhibitors are compromised by the frequently occurring acquired resistance due to cancer heterogeneity and genomic instability. This review briefly introduces the key protein kinases involved in this pathway as well as their activation mechanisms. We also generalize the correlations between mutations of MAPK members and human cancers, followed by a summarization of progress made on the development of small molecule MAPK kinases inhibitors. In particular, this review highlights the potential advantages of ERK inhibitors in overcoming resistance to upstream targets and proposes that targeting ERK kinase may hold a promising prospect for cancer therapy.