Transcriptional Profiling of Non-Small Cell Lung Cancer Cells with Activating EGFR Somatic Mutations

Activating somatic mutations in epidermal growth factor receptor (EGFR) confer unique biologic features to non-small cell lung cancer (NSCLC) cells, but the transcriptional mediators of EGFR in this subgroup of NSCLC have not been fully elucidated.Here we used genetic and pharmacologic approaches to elucidate the transcriptomes of NSCLC cell lines. We transcriptionally profiled a panel of EGFR-mutant and -wild-type NSCLC cell lines cultured in the presence or absence of an EGFR tyrosine kinase inhibitor. Hierarchical analysis revealed that the cell lines segregated on the basis of EGFR mutational status (mutant versus wild-type), and expression signatures were identified by supervised analysis that distinguished the cell lines based on mutational status (wild-type versus mutant) and type of mutation (L858R versus Delta746-750). Using an EGFR mutation-specific expression signature as a probe, we mined the gene expression profiles of two independent cohorts of NSCLC patients and found the signature in a subset. EGFR tyrosine kinase inhibitor treatment regulated the expression of multiple genes, and pharmacologic inhibition of the protein products of two of them (PTGS2 and EphA2) inhibited anchorage-independent growth in EGFR-mutant NSCLC cells.We have elucidated genes not previously associated with EGFR-mutant NSCLC, two of which enhanced the clonogenicity of these cells, distinguishing these mediators from others previously shown to maintain cell survival. These findings have potential clinical relevance given the availability of pharmacologic tools to inhibit the protein products of these genes

Genetics and mechanism of resistance to Meloidogyne arenaria in advanced generation peanut germplasm

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references: p.49-60.Issued also on microfiche from Lange Micrographics.The genetic basis and mechanism for resistance to root-knot nematode was determined in six BCSF2 peanut breeding lines. The donor parent for resistance to root-knot nematode in all breeding lines was TxAG-7 and the recurrent parent used was Florunner in all breeding lines, except TP268-3 for which NC7 was the recurrent parent. Resistance of TxAG-7 was derived from the wild species, Arachis batizocci, A. ca-rdenasii, and A. diogoi. Resistance was defined as an inhibition of nematode reproduction relative to that of the susceptible recurrent parent. The ratio of resistant to susceptible individuals in all six BCSF2 lines was not different (P < 0.05)from that predicted for a single dominant gene. However, segregation ratios for three lines were also consistent with two dominant genes, both heterozygous. To determine the resistance mechanism in the BC5F2 breeding lines, resistant individuals from two BC5F2 peanut breeding lines were vegetatively propagated and used to determine the effect of resistance genes on nematode development. The rate of nematode development in resistant individuals was significantly reduced from that in Florunner. There was definite evidence for hypersensitive response in resistant individuals. The observed difference in nematode development was consistent with the poor development of feeding sites in resistant individuals. Thus, the reduced development of nematode in resistant individuals may be caused by the insufficient uptake of nutrient from poorly developed feedin sites

Genetics and mechanism of resistance to Meloidogyne arenaria in advanced generation peanut germplasm

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references: p.49-60.Issued also on microfiche from Lange Micrographics.The genetic basis and mechanism for resistance to root-knot nematode was determined in six BCSF2 peanut breeding lines. The donor parent for resistance to root-knot nematode in all breeding lines was TxAG-7 and the recurrent parent used was Florunner in all breeding lines, except TP268-3 for which NC7 was the recurrent parent. Resistance of TxAG-7 was derived from the wild species, Arachis batizocci, A. ca-rdenasii, and A. diogoi. Resistance was defined as an inhibition of nematode reproduction relative to that of the susceptible recurrent parent. The ratio of resistant to susceptible individuals in all six BCSF2 lines was not different (P < 0.05)from that predicted for a single dominant gene. However, segregation ratios for three lines were also consistent with two dominant genes, both heterozygous. To determine the resistance mechanism in the BC5F2 breeding lines, resistant individuals from two BC5F2 peanut breeding lines were vegetatively propagated and used to determine the effect of resistance genes on nematode development. The rate of nematode development in resistant individuals was significantly reduced from that in Florunner. There was definite evidence for hypersensitive response in resistant individuals. The observed difference in nematode development was consistent with the poor development of feeding sites in resistant individuals. Thus, the reduced development of nematode in resistant individuals may be caused by the insufficient uptake of nutrient from poorly developed feedin sites

Pathogenicity of Salmonella: SopE-mediated membrane ruffling is independent of inositol phosphate signals

Studies [Zhou, D. Chen, L.-M. Hernandez, L. Shears, S.B. and Galán, J.E. (2001) A Salmonella inositol polyphosphatase acts in conjunction with other bacterial effectors to promote host-cell actin cytoskeleton rearrangements and bacterial internalization. Mol. Microbiol. 39, 248-259] with engineered Salmonella mutants showed that deletion of SopE attenuated the pathogen's ability to deplete host-cell InsP5 and remodel the cytoskeleton. We pursued these observations: In SopE-transfected host-cells, membrane ruffling was induced, but SopE did not dephosphorylate InsP5, nor did it recruit PTEN (a cytosolic InsP5 phosphatase) for this task. However, PTEN strengthened SopE-mediated membrane ruffling. We conclude SopE promotes host-cell InsP5 hydrolysis only with the assistance of other Salmonella proteins. Our demonstration that Salmonella-mediated cytoskeletal modifications are independent of inositolphosphates will focus future studies on elucidating alternate pathogenic consequences of InsP5 metabolism, including ion channel conductance and apoptosis.info:eu-repo/semantics/publishe

Physiological levels of PTEN control the size of the cellular Ins(1,3,4,5,6)P5 pool

To understand how a signaling molecule's activities are regulated, we need insight into the processes controlling the dynamic balance between its synthesis and degradation. For the Ins(1,3,4,5,6)P5 signal, this information is woefully inadequate. For example, the only known cytosolic enzyme with the capacity to degrade Ins(1,3,4,5,6)P5 is the tumour-suppressor PTEN [J.J. Caffrey, T. Darden, M.R. Wenk, S.B. Shears, FEBS Lett. 499 (2001) 6 ], but the biological relevance has been questioned by others [E.A. Orchiston, D. Bennett, N.R. Leslie, R.G. Clarke, L. Winward, C.P. Downes, S.T. Safrany, J. Biol. Chem. 279 (2004) 1116 ]. The current study emphasizes the role of physiological levels of PTEN in Ins(1,3,4,5,6)P5 homeostasis. We employed two cell models. First, we used a human U87MG glioblastoma PTEN-null cell line that hosts an ecdysone-inducible PTEN expression system. Second, the human H1299 bronchial cell line, in which PTEN is hypomorphic due to promoter methylation, has been stably transfected with physiologically relevant levels of PTEN. In both models, a novel consequence of PTEN expression was to increase Ins(1,3,4,5,6)P5 pool size by 30-40% (p<0.01); this response was wortmannin-insensitive and, therefore, independent of the PtdIns 3-kinase pathway. In U87MG cells, induction of the G129R catalytically inactive PTEN mutant did not affect Ins(1,3,4,5,6)P(5) levels. PTEN induction did not alter the expression of enzymes participating in Ins(1,3,4,5,6)P5 synthesis. Another effect of PTEN expression in U87MG cells was to decrease InsP6 levels by 13% (p<0.02). The InsP6-phosphatase, MIPP, may be responsible for the latter effect; we show that recombinant human MIPP dephosphorylates InsP6 to D/L-Ins(1,2,4,5,6)P5, levels of which increased 60% (p<0.05) following PTEN expression in U87MG cells. Overall, our data add higher inositol phosphates to the list of important cellular regulators [Y. Huang, R.P. Wernyj, D.D. Norton, P. Precht, M.C. Seminario, R.L. Wange, Oncogene, 24 (2005) 3819 ] the levels of which are modulated by expression of the highly pleiotropic PTEN protein.info:eu-repo/semantics/publishe

Distinct Biological Roles for the Notch Ligands Jagged-1 and Jagged-2*

Notch signaling is activated in a subset of non-small cell lung cancer cells because of overexpression of Notch3, but the role of Notch ligands has not been fully defined. On the basis of gene expression profiling of a panel of non-small cell lung cancer cell lines, we found that the predominant Notch ligands were JAG1, JAG2, DLL1, and DLL3. Given that Notch ligands reportedly have overlapping receptor binding specificities, we postulated that they have redundant biological roles. Arguing against this hypothesis, we found that JAG1 and JAG2 were differentially regulated; JAG1 expression was dependent upon epidermal growth factor receptor (EGFR) activation in HCC827 cells, which require EGFR for survival, whereas JAG2 expression was EGFR-independent in these cells. Furthermore, HCC827 cells underwent apoptosis following depletion of JAG1 but not JAG2, whereas co-culture experiments revealed that depletion of JAG2, but not JAG1, enhanced the ability of HCC827 cells to chemoattract THP-1 human monocytes. JAG2-depleted HCC827 cells expressed high levels of inflammation-related genes, including interleukin 1 (IL1) and a broad range of IL1-regulated cytokines, which was attenuated by inhibition of IL1 receptor (IL1R). Our findings suggest that JAG1 and JAG2 have distinct biological roles including a previously undiscovered role for JAG2 in regulating the expression of cytokines that can promote antitumor immunity