Hyperactivation of MEK/ERK pathway by Ca2+ /calmodulin-dependent protein kinase kinase 2 promotes cellular proliferation by activating cyclin-dependent kinases and minichromosome maintenance protein in gastric cancer cells.

Although CAMKK2 is overexpressed in several cancers, its role and relevant downstream signaling pathways in gastric cancer (GC) are poorly understood. Treatment of AGS GC cells with a CAMKK2 inhibitor, STO-609, resulted in decreased cell proliferation, cell migration, invasion, colony-forming ability, and G1/S-phase arrest. Quantitative phosphoproteomics in AGS cells with the CAMKK2 inhibitor led to the identification of 9603 unique phosphosites mapping to 3120 proteins. We observed decreased phosphorylation of 1101 phosphopeptides (1.5-fold) corresponding to 752 proteins upon CAMKK2 inhibition. Bioinformatics analysis of hypo-phosphorylated proteins revealed enrichment of MAPK1/MAPK3 signaling. Kinase enrichment analysis of hypo-phosphorylated proteins using the X2K Web tool identified ERK1, cyclin-dependant kinase 1 (CDK1), and CDK2 as downstream substrates of CAMKK2. Moreover, inhibition of CAMKK2 and MEK1 resulted in decreased phosphorylation of ERK1, CDK1, MCM2, and MCM3. Immunofluorescence results were in concordance with our mass spectroscopy data and Western blot analysis results. Taken together, our data reveal the essential role of CAMKK2 in the pathobiology of GC through the activation of the MEK/ERK1 signaling cascade.

Metabolomic fingerprinting of bull spermatozoa for identification of fertility signature metabolites.

The objective of the study was to identify the fertility-associated metabolites in bovine spermatozoa using liquid chromatography-mass spectrometry (LC-MS). Six Holstein Friesian crossbred bulls (three high-fertile and three low-fertile bulls) were the experimental animals. Sperm proteins were isolated and protein-normalized samples were processed for metabolite extraction and subjected to LC-MS/MS analysis. Mass spectrometry data were processed using iMETQ software and metabolites were identified using Human Metabolome DataBase while, Metaboanalyst 4.0 tool was used for statistical and pathway analysis. A total of 3,704 metabolites belonging to various chemical classes were identified in bull spermatozoa. After sorting out exogenous metabolites, 56 metabolites were observed common to both the groups while 44 and 35 metabolites were found unique to high- and low-fertile spermatozoa, respectively. Among the common metabolites, concentrations of 19 metabolites were higher in high-fertile compared to low-fertile spermatozoa (fold change > 1.00). Spermatozoa metabolites with variable importance in projections score of more than 1.5 included hypotaurine, d-cysteine, selenocystine. In addition, metabolites such as spermine and l-cysteine were identified exclusively in high-fertile spermatozoa. Collectively, the present study established the metabolic profile of bovine spermatozoa and identified the metabolomic differences between spermatozoa from high- and low-fertile bulls. Among the sperm metabolites, hypotaurine, selenocysteine, l-malic acid, d-cysteine, and chondroitin 4-sulfate hold the potential to be recognized as fertility-associated metabolites.

Age-dependent expression of S100beta in the brain of mice.

S100beta is a soluble calcium binding protein released by glial cells. It has been reported as a neurotrophic factor that promotes neurite maturation and outgrowth during development. This protein also plays a role in axonal stability and in long term potentiation in the adult brain. The ability of S100beta to modulate neuronal morphology raises the important question whether there is an age-related difference in the expression of S100beta in the cerebral and cerebellar cortices of AKR strain mice and is this change is region specific. Our RT-PCR and Western blotting experiments show that the expression of S100beta gene in the cerebral and cerebellar cortices starts from 0 day, peaks at about 45 days. However, in 70-week old mice its expression is significantly up-regulated as compared to that of 20-week old mice. S100beta follows the same age-related pattern in both cerebral and cerebellar cortices. These results suggest that S100beta is important for brain development and establishment of proper brain functions. Up-regulation of S100beta in old age may have some role in development of age-related pathological systems in the brain.