// Sasha J. Beyer 1 , Erica H. Bell 1 , Joseph P. McElroy 2 , Jessica L. Fleming 1 , Tiantian Cui 1 , Aline Becker 1 , Emily Bassett 1 , Benjamin Johnson 1 , Pooja Gulati 1 , Ilinca Popp 3, 4 , Ori Staszewski 5 , Marco Prinz 5, 6, 7 , Anca L. Grosu 3, 4 , Saikh Jaharul Haque 1 and Arnab Chakravarti 1 1 Department of Radiation Oncology, Arthur G. James Hospital/The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA 2 Center for Biostatistics, The Ohio State University, Columbus, OH, USA 3 Department of Radiation Oncology, Medical Center University of Freiburg, Freiburg, Germany 4 German Cancer Consortium (DKTK), Partner Site, Freiburg, Germany 5 Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany 6 BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany 7 CIBSS Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg, Germany Correspondence to: Arnab Chakravarti, email: chakravarti.7@osu.edu Keywords: transgelin-2; glioma; glioblastoma; isocitrate dehydrogenase (IDH1/2) mutation; invasion Received: October 06, 2018 Accepted: October 24, 2018 Published: December 14, 2018 ABSTRACT The presence of an isocitrate dehydrogenase ( IDH1/2 ) mutation in gliomas is associated with favorable outcomes compared to gliomas without the mutation ( IDH1/2 wild-type, WT). The underlying biological mechanisms accounting for improved clinical outcomes in IDH1/2 mutant gliomas remain poorly understood, but may, in part, be due to the glioma CpG island methylator phenotype (G-CIMP) and epigenetic silencing of genes. We performed profiling of IDH1/2 WT versus IDH1/2 mutant Grade II and III gliomas and identified transgelin-2 ( TAGLN2 ), an oncogene and actin-polymerizing protein, to be expressed at significantly higher levels in IDH1/2 WT gliomas compared to IDH1/2 mutant gliomas. This differential expression of TAGLN2 was primarily due to promoter hypermethylation in IDH1/2 mutant gliomas, suggesting involvement of TAGLN2 in the G-CIMP. Our results also suggest that TAGLN2 may be involved in progression due to higher expression in glioblastomas compared to IDH1/2 WT gliomas of lower grades. Furthermore, our results suggest that TAGLN2 functions as an oncogene by contributing to proliferation and invasion when overexpressed in IDH1/2 WT glioma cells. Taken together, this study demonstrates a possible link between increased TAGLN2 expression, invasion and poor patient outcomes in IDH1/2 WT gliomas and identifies TAGLN2 as a potential novel therapeutic target for IDH1/2 WT gliomas.
Replication-dependent histones are expressed in a cell cycle regulated manner and supply the histones necessary to support DNA replication. In mammals, the replication-dependent histones are encoded by a family of genes that are located in several clusters. In humans, these include 16 genes for histone H2A, 22 genes for histone H2B, 14 genes for histone H3, 14 genes for histone H4 and 6 genes for histone H1. While the proteins encoded by these genes are highly similar, they are not identical. For many years, these genes were thought to encode functionally equivalent histone proteins. However, several lines of evidence have emerged that suggest that the replication-dependent histone genes can have specific functions and may constitute a novel layer of chromatin regulation. This Survey and Summary reviews the literature on replication-dependent histone isoforms and discusses potential mechanisms by which the small variations in primary sequence between the isoforms can alter chromatin function. In addition, we summarize the wealth of data implicating altered regulation of histone isoform expression in cancer.
Glioblastoma (GBM) is an aggressive, malignant brain tumor that often develops resistance to conventional chemotherapy and radiation treatments. In order to identify signaling pathways involved in the development of radiation resistance, we performed mass spectrometry-based phospho-proteomic profiling of 5 GBM cell lines and normal human astrocytes before and after radiation treatment. Fold changes in phosphorylation were calculated for each peptide across all cell lines at 30 seconds and 4 hours post-radiation. We found that radiation induces phosphorylation of calpastatin, an endogenous inhibitor of calpain proteases, specifically in GBM stem cells (GSCs). Radiation-induced phosphorylation of calpastatin at a serine within the inhibitory domain was validated by western blot with a phospho-specific antibody. In order to test the functional significance of phosphorylated calpastatin, we utilized site-directed mutagenesis to generate non-phosphorylatable and phospho-mimetic calpastatin mutants. Western blot analyses of GBM cell lines stably expressing the calpastatin mutant proteins show that calpastatin phosphorylation leads to increased calpain activity following radiation treatment. Our results indicate that calpastatin phosphorylation promotes radiation resistance in GBM by increasing the activity of calpain proteases, which are known to promote survival and invasion in cancers.
<p>Supporting Figures Figure S1. Extracellular and intracellular metabolites of commercially available and patient derived GBM cells and NHAs Figure S2. Total and extracted ion chromatograms of intracellular metabolites Figure S3. Total and extracted ion chromatograms of extracellular metabolites Figure S4. Targeted analysis MS/MS product ion spectrum of methionine Figure S5. Targeted analysis MS/MS product ion spectrum of tryptophan Figure S6. Targeted analysis MS/MS product ion spectrum of kynurenine Figure S7. Targeted analysis MS/MS product ion spectrum of MTA Figure S8. Total ion chromatogram and multiple reaction monitoring of different concentrations of methionine Figure S9. Total ion chromatogram and multiple reaction monitoring of different concentrations of kynurenine Figure S10. Key metabolites in methionine pathway Figure S11. Calibration Curve and Multiple Reaction Monitoring of SAM and SAH Figure S12. Key metabolites in tryptophan pathway Figure S13. Insilico analysis - Connecting metabolome and proteome in GBM cells Figure S14. Densitometric quantification of the chemiluminescence signals</p>
<p>Supporting Figures Figure S1. Extracellular and intracellular metabolites of commercially available and patient derived GBM cells and NHAs Figure S2. Total and extracted ion chromatograms of intracellular metabolites Figure S3. Total and extracted ion chromatograms of extracellular metabolites Figure S4. Targeted analysis MS/MS product ion spectrum of methionine Figure S5. Targeted analysis MS/MS product ion spectrum of tryptophan Figure S6. Targeted analysis MS/MS product ion spectrum of kynurenine Figure S7. Targeted analysis MS/MS product ion spectrum of MTA Figure S8. Total ion chromatogram and multiple reaction monitoring of different concentrations of methionine Figure S9. Total ion chromatogram and multiple reaction monitoring of different concentrations of kynurenine Figure S10. Key metabolites in methionine pathway Figure S11. Calibration Curve and Multiple Reaction Monitoring of SAM and SAH Figure S12. Key metabolites in tryptophan pathway Figure S13. Insilico analysis - Connecting metabolome and proteome in GBM cells Figure S14. Densitometric quantification of the chemiluminescence signals</p>
