Effects of salt stress levels on five maize (Zea mays L.) cultivars at germination stage

To investigation the effects of salt stress levels (0, 50, 100, 150, 200 and 250 mM NaCl) on five maize (Zea mays L.) cultivars at germination stage, this study was performed at Ardabil, Iran in 2011. The results showed that in all cultivars, as the salt concentration increased, both germination percentage and germination index decreased significantly. Increasing salt concentration affected the early seedling growth in all cultivars. There were differences in responses of cultivars to salt stress. For all salt concentrations, Golden west had the highest germination percentage and germination index. Salt concentration decreased shoot and root dry weight. BC678 and Golden west had the lowest reduction of shoot and root dry weight, respectively. OS 499 had the highest reduction of shoot and root dry weight in this study; Golden west showed better results than the other cultivars in respect to salt tolerance index. The results show that Golden west was the cultivar to be recommended for saline soils. OS499 was more sensitive to salinity in this study.Key words: Corn, germination, salt stress, NaCl, germination index

Developmental phosphoproteomics identifies the kinase CK2 as a driver of Hedgehog signaling and a therapeutic target in medulloblastoma

A major limitation of targeted cancer therapy is the rapid emergence of drug resistance, which often arises through mutations at or downstream of the drug target or through intrinsic resistance of subpopulations of tumor cells. Medulloblastoma (MB), the most common pediatric brain tumor, is no exception, and MBs that are driven by sonic hedgehog (SHH) signaling are particularly aggressive and drug-resistant. To find new drug targets and therapeutics for MB that may be less susceptible to common resistance mechanisms, we used a developmental phosphoproteomics approach in murine granule neuron precursors (GNPs), the developmental cell of origin of MB. The protein kinase CK2 emerged as a driver of hundreds of phosphorylation events during the proliferative, MB-like stage of GNP growth, including the phosphorylation of three of the eight proteins commonly amplified in MB. CK2 was critical to the stabilization and activity of the transcription factor GLI2, a late downstream effector in SHH signaling. CK2 inhibitors decreased the viability of primary SHH-type MB patient cells in culture and blocked the growth of murine MB tumors that were resistant to currently available Hh inhibitors, thereby extending the survival of tumor-bearing mice. Because of structural interactions, one CK2 inhibitor (CX-4945) inhibited both wild-type and mutant CK2, indicating that this drug may avoid at least one common mode of acquired resistance. These findings suggest that CK2 inhibitors may be effective for treating patients with MB and show how phosphoproteomics may be used to gain insight into developmental biology and pathology

Epigenetic targeting of Hedgehog pathway transcriptional output through BET bromodomain inhibition

Hedgehog signaling drives oncogenesis in several cancers and strategies targeting this pathway have been developed, most notably through inhibition of Smoothened. However, resistance to Smoothened inhibitors occurs via genetic changes of Smoothened or other downstream Hedgehog components. Here, we overcome these resistance mechanisms by modulating GLI transcription via inhibition of BET bromodomain proteins. We show the BET bromodomain protein, BRD4, regulates GLI transcription downstream of SMO and SUFU and chromatin immunoprecipitation studies reveal BRD4 directly occupies GLI1 and GLI2 promoters, with a substantial decrease in engagement of these sites upon treatment with JQ1, a small molecule inhibitor targeting BRD4. Globally, genes associated with medulloblastoma-specific GLI1 binding sites are downregulated in response to JQ1 treatment, supporting direct regulation of GLI activity by BRD4. Notably, patient- and GEMM-derived Hedgehog-driven tumors (basal cell carcinoma, medulloblastoma and atypical teratoid/rhabdoid tumor) respond to JQ1 even when harboring genetic lesions rendering them resistant to Smoothened antagonists

Gpr124 is essential for blood-brain barrier integrity in central nervous system disease

Although blood-brain barrier (BBB) compromise is central to the etiology of diverse central nervous system (CNS) disorders, endothelial receptor proteins that control BBB function are poorly defined. The endothelial G-protein-coupled receptor (GPCR) Gpr124 has been reported to be required for normal forebrain angiogenesis and BBB function in mouse embryos, but the role of this receptor in adult animals is unknown. Here Gpr124 conditional knockout (CKO) in the endothelia of adult mice did not affect homeostatic BBB integrity, but resulted in BBB disruption and microvascular hemorrhage in mouse models of both ischemic stroke and glioblastoma, accompanied by reduced cerebrovascular canonical Wnt-β-catenin signaling. Constitutive activation of Wnt-β-catenin signaling fully corrected the BBB disruption and hemorrhage defects of Gpr124-CKO mice, with rescue of the endothelial gene tight junction, pericyte coverage and extracellular-matrix deficits. We thus identify Gpr124 as an endothelial GPCR specifically required for endothelial Wnt signaling and BBB integrity under pathological conditions in adult mice. This finding implicates Gpr124 as a potential therapeutic target for human CNS disorders characterized by BBB disruption

Ectopic Expression of Embryo/Cancer Sequence A (ECSA) in KYSE-30 Cell Line Using Retroviral System

Background Human preimplantation embryonic cells share many similarities with cancer cells such as ability to self-renew, unlimited proliferation and maintenance of the undifferentiated state. Embryo-cancer sequence A (ECSA), also known as developmental pluripotency associated-2 (DPPA2), is a cancer testis antigen (CTA) with unclear biological function yet. Objective: CTAs are expressed normally in germ line cells and trophoblast, and aberrantly in a variety of cancers. According to the importance of ECSA in developmental events and cancer, preparing a suitable platform to analyze its roles seems necessary. Methods The coding sequence of the gene was amplified and sub-cloned in pRUF retroviral expression vector. pRUF- ECSA vector was cotransfected with pVSV-G to GP293 cells and with pVSV-G and pGP to HEK293 packaging cell lines. Then the viral particles were transducted to KYSE-30 cells and the concentration of retroviral particles was determined by Real time PCR. Results  The coding sequence of ECSA gene was successfully subcloned in pRUF expression vector and transfected to packaging cells that the efficiency of transfection to GP293 was higher than the HEK293 cells. The enriched virus particles were obtained at a final concentration of 105 TU/ml. Conclusion  Considering the critical characteristics of retroviral expression system such as stable and longtime expression of interested gene, being safe due to the deletion of retroviral pathogenic genes, and since the function of ECSA gene is not clear, we used this system to induce expression of ECSA and prepared a valuable platform to analyze the biological function of the gene. Also the recombinant ECSA protein can be used in production of recombinant vaccines and serological tests. Keywords: DPPA2, ECSA, Embryo/cancer gene, KYSE cell line, Retroviral expression system