THOR-05F biofidelity evaluation in reclined and upright seated postures subjected to frontal crash pulses

The THOR 5th percentile female dummy (THOR-05F) was evaluated for two seating postures/positions in frontal impacts using a generic automotive seat environment. The conditions included 2 crash pulses: a 15 km/h test that utilized 4.5 g acceleration and a 3-point restraint with 2 kN load limiter, and a 32 km/h test that utilized 9.5 g acceleration and a 3-point restraint with a 4.5 kN load limiter and pretensioner, and two seatback angles: 25°, a nominal upright posture, and 45°, a moderate reclined posture. The BRS scores were calculated using the NHTSA BioRank method. Overall biofidelity rating was consider excellent for both seating postures. This evaluation provides an understanding of the THOR-05F response and biofidelity evaluation of the ATD in two seating postures (nominal and reclined). This is essential in the assessment and development of safety measures in emerging ADS-equipped vehicles.

Data from Survival Signaling by Notch1: Mammalian Target of Rapamycin (mTOR)–Dependent Inhibition of p53.. [DOI: 10.1158/0008-5472.c.6494948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<div>Abstract<p>Notch signaling is believed to promote cell survival in general. However, the mechanism is not clearly understood. Here, we show that cells expressing intracellular domain of human Notch1 (NIC-1) are chemoresistant in a wild-type p53-dependent manner. NIC-1 inhibited p53 by inhibiting its activating phosphorylations at Ser¹⁵, Ser²⁰, and Ser³⁹² as well as nuclear localization. In addition, we found that inhibition of p53 by NIC-1 mainly occurs through <i>m</i>ammalian <i>t</i>arget <i>o</i>f <i>r</i>apamycin (mTOR) using phosphatidylinositol 3-kinase (PI3K)-Akt/protein kinase B (PKB) pathway as the mTOR inhibitor, rapamycin treatment abrogated NIC-1 inhibition of p53 and reversed the chemoresistance. Consistent with this, rapamycin failed to reverse NIC-1-induced chemoresistance in cells expressing rapamycin-resistant mTOR. Further, ectopic expression of eukaryotic initiation factor 4E (eIF4E), a translational regulator that acts downstream of mTOR, inhibited p53-induced apoptosis and conferred protection against p53-mediated cytotoxicity to similar extent as that of NIC-1 overexpression but was not reversed by rapamycin, which indicates that eIF4E is the major target of mTOR in Notch1-mediated survival signaling. Finally, we show that MCF7 (breast cancer) and MOLT4 (T-cell acute lymphoblastic leukemia) cells having aberrant Notch1 signaling are chemoresistant, which can be reversed by both PI3K and mTOR inhibitors. These results establish that Notch1 signaling confers chemoresistance by inhibiting p53 pathway through mTOR-dependent PI3K-Akt/PKB pathway and imply that p53 status perhaps is an important determinant in combination therapeutic strategies, which use mTOR inhibitors and chemotherapy. (Cancer Res 2006; 66(9): 4715-24)</p></div>

Data from Survival Signaling by Notch1: Mammalian Target of Rapamycin (mTOR)–Dependent Inhibition of p53.. [DOI: 10.1158/0008-5472.c.6494948.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<div>Abstract<p>Notch signaling is believed to promote cell survival in general. However, the mechanism is not clearly understood. Here, we show that cells expressing intracellular domain of human Notch1 (NIC-1) are chemoresistant in a wild-type p53-dependent manner. NIC-1 inhibited p53 by inhibiting its activating phosphorylations at Ser¹⁵, Ser²⁰, and Ser³⁹² as well as nuclear localization. In addition, we found that inhibition of p53 by NIC-1 mainly occurs through <i>m</i>ammalian <i>t</i>arget <i>o</i>f <i>r</i>apamycin (mTOR) using phosphatidylinositol 3-kinase (PI3K)-Akt/protein kinase B (PKB) pathway as the mTOR inhibitor, rapamycin treatment abrogated NIC-1 inhibition of p53 and reversed the chemoresistance. Consistent with this, rapamycin failed to reverse NIC-1-induced chemoresistance in cells expressing rapamycin-resistant mTOR. Further, ectopic expression of eukaryotic initiation factor 4E (eIF4E), a translational regulator that acts downstream of mTOR, inhibited p53-induced apoptosis and conferred protection against p53-mediated cytotoxicity to similar extent as that of NIC-1 overexpression but was not reversed by rapamycin, which indicates that eIF4E is the major target of mTOR in Notch1-mediated survival signaling. Finally, we show that MCF7 (breast cancer) and MOLT4 (T-cell acute lymphoblastic leukemia) cells having aberrant Notch1 signaling are chemoresistant, which can be reversed by both PI3K and mTOR inhibitors. These results establish that Notch1 signaling confers chemoresistance by inhibiting p53 pathway through mTOR-dependent PI3K-Akt/PKB pathway and imply that p53 status perhaps is an important determinant in combination therapeutic strategies, which use mTOR inhibitors and chemotherapy. (Cancer Res 2006; 66(9): 4715-24)</p></div>

PI and weighted PI indices for powers of paths, cycles, and their complements

 Topological indices play a significant role in molecular chemistry, spectral graph theory, network theory, etc. We aim to contribute some new results on PI and weighted PI indices. The vertex PI index of a graph G is given by, PI (G) = ∑ e∈E(G) (|V (G) | - N G  (e)). The weighted PI index of a graph G is given by, PI w  (G) = ∑ e=(u,v)∈E(G) (d G  (u) + d G  (v)) (|V (G) | - N G  (e)). We obtained the PI and weighted PI indices for powers of paths, cycles, and their complements in this study. Also, for a regular graph, a relationship between PI and weighted PI indices is established, and using this relation the weighted PI index is calculated for k th power of a cycle.

LncRNAs divide and rule: The master regulators of phase separation

Most of the human genome, except for a small region that transcribes protein-coding RNAs, was considered junk. With the advent of RNA sequencing technology, we know that much of the genome codes for RNAs with no protein-coding potential. Long non-coding RNAs (lncRNAs) that form a significant proportion are dynamically expressed and play diverse roles in physiological and pathological processes. Precise spatiotemporal control of their expression is essential to carry out various biochemical reactions inside the cell. Intracellular organelles with membrane-bound compartments are known for creating an independent internal environment for carrying out specific functions. The formation of membrane-free ribonucleoprotein condensates resulting in intracellular compartments is documented in recent times to execute specialized tasks such as DNA replication and repair, chromatin remodeling, transcription, and mRNA splicing. These liquid compartments, called membrane-less organelles (MLOs), are formed by liquid–liquid phase separation (LLPS), selectively partitioning a specific set of macromolecules from others. While RNA binding proteins (RBPs) with low complexity regions (LCRs) appear to play an essential role in this process, the role of RNAs is not well-understood. It appears that short nonspecific RNAs keep the RBPs in a soluble state, while longer RNAs with unique secondary structures promote LLPS formation by specifically binding to RBPs. This review will update the current understanding of phase separation, physio-chemical nature and composition of condensates, regulation of phase separation, the role of lncRNA in the phase separation process, and the relevance to cancer development and progression.

An Improved Machine Learning Model for Diagnostic Cancer Recognition Using Artificial Intelligence

In the medical field, some specialized applications are currently being used to treat various ailments. These activities are being carried out with extra care, especially for cancer patients. Physicians are seeking the help of technology to help diagnose cancer, its dosage, its current status, cancer classification, and appropriate treatment. The machine learning method developed by an artificial intelligence is proposed here in order to effectively assist the doctors in that regard. Its design methods obtain highly complex cancerous inputs and clearly describe its type and dosage. It is also recommending the effects of cancer and appropriate medical procedures to the doctors. This method ensures that a lot of doctors' time is saved. In a saturation point, the proposed model achieved 93.31% of image recognition, 6.69% of image rejection, 94.22% accuracy, 92.42% of precision, 93.94% of recall rate, 92.6% of F1-score, and 2178 ms of computational speed. This shows that the proposed model performs well while compared with the existing methods.

Abstract 6383: Paracrine signaling between differentiated tumor cell-secreted fibromodulin and the stroma promotes tumor growth by enhancing angiogenesis

Cancer stem-like cells (CSCs) and the differentiated bulk cells mainly contribute to cellular heterogeneity within a tumor. The dichotomous division pattern of the CSCs sitting atop the tumor hierarchy allow them to self-renew, and differentiate to initiate and repopulate aggressive tumors. These CSC-differentiation-derived bulk tumor cells reprogram to stem-like states, accounting for high plasticity within a tumor; a phenomenon governed by the distinct epigenetic profiles of the two cell populations. Reciprocal signaling between the tumor and its complex microenvironment is a vital driver of plasticity and heterogeneity in cancer. The indispensable role of CSCs in cellular cross-talk in the tumor niche as critical drivers of tumorigenesis is well-studied. However, the massive outnumbering of the CSCs by the differentiated cells raises several vital questions regarding the role of the latter in tumor growth; whether they contribute to the complex signaling within the tumor microenvironment (TME) to drive tumor growth remains unexplored. In this study, we aimed to mechanistically delineate the distinct roles of the cancer stem-like and differentiated cells by investigating their interactions with other stromal cells in the TME.In our model system, Glioblastoma (GBM), a highly aggressive brain cancer, we adopted a quantitative, label-free, high-throughput proteomics-based approach to identify the differentially abundant secreted proteins between the glioma stem-like cell (GSC) and differentiated glioma cell (DGC). This analysis showed a significantly higher abundance of the Fibromodulin (FMOD), a collagen-binding proteoglycan, in the conditioned medium of the DGCs compared with that of the GSCs. Our investigation revealed that an activated TGF-β signaling leads to p-SMAD2 occupancy on the FMOD promoter region, leading to increased FMOD secretion by the DGCs. DGCs silenced for FMOD fail to cooperate with co-implanted GSCs to promote tumor growth in a subcutaneous mouse model. We also observed that FMOD downregulation neither affects GSC growth and differentiation nor DGC growth and reprogramming in vitro. Moreover, DGC-secreted FMOD activates integrin-dependent Notch signaling in endothelial cells, promoting angiogenesis. FMOD-silencing also inhibits the capability of the transdifferentiated endothelial cells (derived from the DGCs) to form angiogenic networks. Conditional silencing of FMOD in the de novo formed DGCs in an orthotopic intracranial C57BL/6 mouse model inhibited the growth of GSC-initiated tumors due to poorly developed vasculature, thereby increasing mouse survival. The same observation was recapitulated using patient-derived GSCs in an immunocompromised intracranial mouse model, thereby highlighting the human relevance of our findings. Collectively, our findings demonstrate how paracrine signaling between DGC-secreted FMOD and the stromal cells promotes tumor growth by enhancing angiogenesis, thereby highlighting a previously less studied supportive role of DGCs in tumor growth, albeit the GSCs retaining the tumor-initiating capacity. Thus our study identifies DGC-specific FMOD as a potential therapeutic target and emphasizes that targeting both cancer stem cells and differentiated cancer bulk cells is vital to achieving a durable response in GBM.

Citation Format: Shreoshi Sengupta, Kumaravel Somasundaram, Dinorah Friedmann Morvinski, Philippe Marin, Prasasvi Reddy, Arani Mukherjee, Prerna Magod, Mainak Mondal, Serge Urbach. Paracrine signaling between differentiated tumor cell-secreted fibromodulin and the stroma promotes tumor growth by enhancing angiogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6383.

Integrative analysis of cell adhesion molecules in glioblastoma identified prostaglandin F2 receptor inhibitor (PTGFRN) as an essential gene

Background

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults exhibiting infiltration into surrounding tissues, recurrence, and resistance to therapy. GBM infiltration is accomplished by many deregulated factors such as cell adhesion molecules (CAMs), which are membrane proteins that participate in cell-cell and cell-ECM interactions to regulate survival, proliferation, migration, and stemness.

Methods

A comprehensive bioinformatics analysis of CAMs (n = 518) in multiple available datasets revealed genetic and epigenetic alterations among CAMs in GBM. Univariate Cox regression analysis using TCGA dataset identified 127 CAMs to be significantly correlated with survival. The poor prognostic indicator PTGFRN was chosen to study its role in glioma. Silencing of PTGFRN in glioma cell lines was achieved by the stable expression of short hairpin RNA (shRNA) against the PTGFRN gene. PTGFRN was silenced and performed cell growth, migration, invasion, cell cycle, and apoptosis assays. Neurosphere and limiting dilution assays were also performed after silencing of PTGFRN in GSCs.

Results

Among the differentially regulated CAMs (n = 181, 34.9%), major proportion of them were found to be regulated by miRNAs (n = 95, 49.7%) followed by DNA methylation (n = 32, 16.7%), and gene copy number variation (n = 12, 6.2%). We found that PTGFRN to be upregulated in GBM tumor samples and cell lines with a significant poor prognostic correlation with patient survival. Silencing PTGFRN diminished cell growth, colony formation, anchorage-independent growth, migration, and invasion and led to cell cycle arrest and induction of apoptosis. At the mechanistic level, silencing of PTGFRN reduced pro-proliferative and promigratory signaling pathways such as ERK, AKT, and mTOR. PTGFRN upregulation was found to be due to the loss of its promoter methylation and downregulation of miR-137 in GBM. PTGFRN was also found to be higher in glioma stem-like cells (GSCs) than the matched differentiated glioma cells (DGCs) and is required for GSC growth and survival. Silencing of PTGFRN in GSCs reduced transcript levels of reprogramming factors (Olig2, Pou3f2, Sall2, and Sox2).

Conclusion

In this study, we provide a comprehensive overview of the differential regulation of CAMs and the probable causes for their deregulation in GBM. We also establish an oncogenic role of PTGFRN and its regulation by miR-137 in GBM, thus signifying it as a potential therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09682-2.

Differentiated glioma cell-derived Fibromodulin activates Integrin-dependent Notch signaling in endothelial cells to promote tumor angiogenesis and growth

Cancer stem cells (CSCs) alone can initiate and maintain tumors, but the function of non-cancer stem cells (non-CSCs) that form the tumor bulk remains poorly understood. Proteomic analysis showed a higher abundance of the extracellular matrix small leucine-rich proteoglycan fibromodulin (FMOD) in the conditioned medium of differentiated glioma cells (DGCs), the equivalent of glioma non-CSCs, compared to that of glioma stem-like cells (GSCs). DGCs silenced for FMOD fail to cooperate with co-implanted GSCs to promote tumor growth. FMOD downregulation neither affects GSC growth and differentiation nor DGC growth and reprogramming in vitro. DGC-secreted FMOD promotes angiogenesis by activating integrin-dependent Notch signaling in endothelial cells. Furthermore, conditional silencing of FMOD in newly generated DGCs in vivo inhibits the growth of GSC-initiated tumors due to poorly developed vasculature and increases mouse survival. Collectively, these findings demonstrate that DGC-secreted FMOD promotes glioma tumor angiogenesis and growth through paracrine signaling in endothelial cells and identifies a DGC-produced protein as a potential therapeutic target in glioma.

346 Accuracy of Tympanic Versus Digital Infra-Red Thermometers for Measuring Core Body Temperature in Critical Care Department - a Quality Improvement Project During Covid-19 Redeployment at a District General Hospital in Surrey, England

Aim

Accurate determination of core body temperature in critically ill patients is required for initiating diagnosis and management. (1) Ideally, temperature measurement should be non-invasive, hygienic, convenient, and affordable. Infrared thermometers are convenient and non-invasive but sensitive to environmental factors. Alternatively, tympanic thermometers are cost effective but invasive. Various observational studies have concluded that tympanic thermometers have high specificity/sensitivity compared to infrared thermometers (2,3). We aimed to demonstrate accuracy of tympanic over infrared thermometers.

Method

In this observational prospective study, eighty patients (forty each) admitted in intensive care from February 2021 – July 2021 were included. Temperature measurements with were conducted - measuring differences between digital and tympanic thermometers. A Plan Do Study Act cycle was used to facilitate change. Excel and SPSS software were used for data analysis.

Results

Our study concluded a statistically significant (p&lt;0.01) difference in readings with mean difference of 1.18°C (highest -6°C, lowest- 0.5°C). Pyrexia was undetected in 4 of 40 patients with digital thermometers. Additionally, two patients undergoing hypothermia correction were not adequately measured. Therefore, infrared thermometers were significantly less sensitive and were replaced with tympanic thermometers. A second cycle conducted again demonstrated significant (p&lt;0.01) difference with mean difference of 1.92°C. (highest -6.5°C, lowest -1°C).

Conclusions

Tympanic thermometers have higher accuracy and precision over digital thermometers. We managed to establish change during our audit with concluding evidence showing infrared thermometers procure false observations affecting patient care, hence, unsafe. In conclusion, tympanic thermometers should be encouraged in critical care settings for vigilant care.

Automatic Facial Emotional Valence Detection System Modelling Using Crafted Features and Deep Neural Network

This work provides a method that merges handcrafted and automatic feature extraction with deep convolutional neural network (D-CNN) and visualization bagging (VB) to acquire effectual and improved results from traditional facial expression recognition (FER) results. To acquire features, pre-trained model with D-CNN architecture is experimented with Dense and over sparse network. After extracting merged information, it is imposed over every featured image to protect structural information of all textured image. Therefore, dimensionality reduction of implicit feature extraction is done with maximal pooling approach. At last, deep CNN is used to recognize class label only for testing images that was trained and classified using soft-max classifier. To validate robustness for recognizing facial expression under complex setup, simulation was performed by merging available dataset with online dataset. Experimental results demonstrate that anticipated model can acquire recognition rate with training speed on training image is approximately two times faster than that of prevailing model. The anticipated model shows better trade off in comparison with prevailing models. Simulation is done with MATLAB simulation environment.

Global RNA editome landscape discovers reduced RNA editing in glioma: loss of editing of gamma-amino butyric acid receptor alpha subunit 3 (GABRA3) favors glioma migration and invasion

Background

Gliomas are the most common and lethal type of intracranial tumors. With the current treatment regime, the median survival of patients with grade IV glioma (glioblastoma/GBM) remains at 14-16 months. RNA editing modifies the function and regulation of transcripts. The development of glial tumors may be caused by altered RNA editing events.

Methods

In this study, we uncover the global RNA editome landscape of glioma patients from RNA-seq data of control, lower grade glioma (LGG) and GBM samples (n = 1,083).

Results

A-to-I editing events were found to comprise 80% of the total editing events of which 96% were located in the Alu regions. The total RNA editing events were found to be reduced in glioma compared to control samples. More specifically, we found Gamma-aminobutyric acid type A receptor alpha3 (GABRA3) to be edited (c.1026 A-to-G; pI343M) in 73% (editing ratio 0.8) of control samples compared to LGG (28.96%; 0.47) and GBM (5.2%; 0.53) samples. GABRA3 transcript level was found to be downregulated in glioma compared to control in a grade-specific manner with GBMs having the lowest level of the transcript. Further, GABRA3 transcripts were observed to be higher in edited compared to unedited glioma samples. The transcript and protein levels of exogenously expressed gene were found to be higher for edited compared to unedited GABRA3 in glioma cells. Further, exogenously expressed edited GABRA3 inhibited migration and invasion of glioma cells efficiently but not the unedited GABRA3.

Conclusion

Collectively, our study discovered a reduction in RNA editing during glioma development. We further demonstrate that elevated RNA editing maintains a high level of GABRA3 RNA and protein in normal glial cells which provides a less migratory environment for the normal functioning of the brain. In contrast, the reduction in GABRA3 protein levels, due to lower stability of unedited RNA, results in the loss of function which confers an aggressive phenotype to GBM tumor.

Serine/threonine/tyrosine-interacting-like protein 1 (STYXL1), a pseudo phosphatase, promotes oncogenesis in glioma

Phosphatases play an important role in cellular signaling and are often found dysregulated in cancers including glioblastoma (GBM). A comprehensive bioinformatics analysis of phosphatases (n = 403) in multiple datasets revealed their deregulation in GBM. Among the differentially regulated phosphatases (n = 186; 46.1%), majority of them were found to be regulated by microRNA (n = 94; 50.5%) followed by DNA methylation (n = 22; 11.8%) and altered copy number variation (n = 10; 5.37%). STYXL1 (Serine/threonine/tyrosine-interacting-like protein 1) was found to be the second most amplified gene in GBM, upregulated, and correlated to poor prognosis. The expression of STYXL1 was also found to be higher in IDH1 mutant gliomas and G-CIMP- gliomas which are reported to be more aggressive than their corresponding counterparts. Silencing STYXL1 inhibited glioma cell growth, soft agar colony formation, migration, invasion, proliferation, and xenograft tumor growth. Further, ectopic expression of STYXL1 was found to promote glioma cell growth, soft agar colony formation, migration, and RasV12 induced in-vitro transformation of immortalized human astrocytes, thus confirming its oncogenic potential in GBM. In this report, we provide a comprehensive overview of deregulation of phosphatases in GBM and demonstrate for the first time, the oncogenic nature of STYXL1 in GBM. This study might be useful for treatment of GBM patients with deregulated STYXL1.

Glioblastoma vs temozolomide: can the red queen race be won?

Glioblastoma is the most invasive form of brain tumor. Although temozolomide chemotherapy has been shown to significantly improve survival in patients with GBM, this increase is only trivial. The underlying cause is that many GBMs do not respond to temozolomide, and the rest produces resistance. In the past two decades, many attempts have been made to understand resistance mechanisms and to combine other treatments with temozolomide to maximize patient benefit. Unfortunately, it seems to be a red queen game, and the speed of disease development is as fast as the progress in the field. In order to win this game, a comprehensive approach is needed to decipher the details of the resistance mechanism and to transfer the basic research to the clinic. This article reviews the following: temozolomide discovery, chemistry, and mechanism of action, and mechanisms of resistance, as well as combination therapy with other strategies.

N⁶-Methyladenosine Landscape of Glioma Stem-Like Cells: METTL3 Is Essential for the Expression of Actively Transcribed Genes and Sustenance of the Oncogenic Signaling

Despite recent advances in N⁶-methyladenosine (m⁶A) biology, the regulation of crucial RNA processing steps by the RNA methyltransferase-like 3 (METTL3) in glioma stem-like cells (GSCs) remains obscure. An integrated analysis of m⁶A-RIP (RNA immunoprecipitation) and total RNA-Seq of METTL3-silenced GSCs identified that m⁶A modification in GSCs is principally carried out by METTL3. The m⁶A-modified transcripts showed higher abundance compared to non-modified transcripts. Further, we showed that the METTL3 is essential for the expression of GSC-specific actively transcribed genes. Silencing METTL3 resulted in the elevation of several aberrant alternative splicing events. We also found that putative m⁶A reader proteins play a key role in the RNA stabilization function of METTL3. METTL3 altered A-to-I and C-to-U RNA editing events by differentially regulating RNA editing enzymes ADAR and APOBEC3A. Similar to protein-coding genes, lincRNAs (long intergenic non-coding RNAs) with m⁶A marks showed METTL3-dependent high expression. m⁶A modification of 3'UTRs appeared to result in a conformation-dependent hindrance to miRNA binding to their targets. The integrated analysis of the m⁶A regulome in METTL3-silenced GSCs showed global disruption in tumorigenic pathways that are indispensable for GSC maintenance and glioma progression. We conclude that METTL3 plays a vital role in many steps of RNA processing and orchestrates successful execution of oncogenic pathways in GSCs.

Targeted Proteomics Comes to the Benchside and the Bedside: Is it Ready for Us?

While mass spectrometry (MS)-based quantification of small molecules has been successfully used for decades, targeted MS has only recently been used by the proteomics community to investigate clinical questions such as biomarker verification and validation. Targeted MS holds the promise of a paradigm shift in the quantitative determination of proteins. Nevertheless, targeted quantitative proteomics requires improvisation in making sample processing, instruments, and data analysis more accessible. In the backdrop of the genomic era reaching its zenith, certain questions arise: is the proteomic era about to come? If we are at the beginning of a new future for protein quantification, are we prepared to incorporate targeted proteomics at the benchside for basic research and at the bedside for the good of patients? Here, an overview of the knowledge required to perform targeted proteomics as well as its applications is provided. A special emphasis is placed on upcoming areas such as peptidomics, proteoform research, and mass spectrometry imaging, where the utilization of targeted proteomics is expected to bring forth new avenues. The limitations associated with the acceptance of this technique for mainstream usage are also highlighted. Also see the video abstract here https://youtu.be/mieB47B8gZw.

Assessment of Radiation Resistance and Therapeutic Targeting of Cancer Stem Cells: A Raman Spectroscopic Study of Glioblastoma

Radiation is the standard therapy used for treating Glioblastoma (GBM), a grade IV brain cancer. Glioma Stem-like Cells (GSCs), an integral part of GBM, enforces resistance to radiation therapy of GBM. Studying the differential biomolecular composition of GSCs with varying levels of radiation sensitivity can aid in identifying the molecules and their associated pathways which impose resistance to cells thereby unraveling new targets which would serve as potential adjuvant therapy. Raman spectroscopy being a noninvasive, label free technique can determine the biomolecular constituent of cells under live conditions. In this study, we have deduced Raman spectral signatures to predict the radiosensitivity of any GSC accurately using the inherent and radiation induced biomolecular composition. Our study identified the differential regulation of several biomolecules which can be potential targets for adjuvant therapy. We radiosensitized the resistant GSCs using small molecule inhibitors specific to the metabolic pathways of these biomolecules. Efficient antitumor therapy can be attained with lower dosage of radiation along with these inhibitors and thus improving the survival rate of GBM patients with reduced side-effects from radiation.

Abstract LB-098: Pooled shRNA screen uncovered the role of SEL1L, an ERAD (endoplasmic reticulum associated degradation) gene, in modulating temozolomide resistance in GBM

Glioblastoma (GBM) is the most aggressive form of adult brain tumors with a poor median survival of less than 15 months. The alkylating agent temozolomide is used for chemotherapy for GBM. Regardless of the rigorous therapeutic regime, almost all cases develop resistance and recur. The mechanisms of the inherent and acquired resistance are less understood and demand in-depth research. We performed a pooled and bar-coded shRNA screen (5045 shRNAs) in a glioma cell line to identify mediators of temozolomide resistance in GBM. The data was analyzed by the HitSelect algorithm, and the top ranking genes imparting resistance (n=257) and sensitivity (n=256) were further subjected to gene set enrichment analysis (GSEA), Gene Ontology (GO) annotation and survival analysis in The Cancer Genome Atlas (TCGA) GBM cohort. An enrichment of translation and protein synthesis-related pathways was found in sensitivity genes, while enrichment of proliferation, metabolic processes, cytokine-cytokine receptor interaction and response to stress was found in resistance genes. Suppressor of Lin-12-Like Protein 1 (SEL1L) was identified as one of the top ranking genes in our screen that caused resistance to temozolomide. SEL1L is a component gene of the endoplasmic-reticulum-associated protein degradation (ERAD). It is known to play an important role in clearing misfolded proteins from cells, thus maintaining proteostasis. SEL1L was found to be a poor prognostic marker in the TCGA GBM cohort treated with temozolomide, as identified by univariate and Kaplan- Meier analysis. In vitro SEL1L knockdown resulted in a significant reduction of proliferation and in an increased sensitivity towards temozolomide. Upon temozolomide treatment of cells in the SEL1L knockdown condition, an increase in apoptosis was observed as measured by Annexin V staining. In vivo tumor showed increased SEL1L protein levels as compared to control brain and mice tumor that responded to temozolomide. We subjected to GSEA, (i) the genes that exhibited survival significance in the TCGA GBM cohort with temozolomide, as well as (ii) the genes that showed differential expression in the SEL1L low and high expression groups. Interestingly, both these analyses identified significant enrichment of overlapping pathways like TNFA mediated NF-kappaB signaling, EMT, IL6 STAT3 signaling, G2M checkpoint and E2F target genes, further highlighting the role of SEL1L in temozolomide resistance. This underscores that SEL1L is an important mediator for temozolomide resistance and is a poor prognosticator in GBM. SEL1L high expression correlates with various resistance-related signaling pathways. Our study emphasizes on the interplay between these pathways and the ERAD machinery in maintaining proteostasis in response to chemotherapeutic stress.

Citation Format: Anjali Arora, Vivek Singh Tomar, Sannu Thomas, Vikas Patil, Jörg Hoheisel, Kumaravel Somasundaram. Pooled shRNA screen uncovered the role of SEL1L, an ERAD (endoplasmic reticulum associated degradation) gene, in modulating temozolomide resistance in GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-098.

IGF2 mRNA binding protein 3 (IMP3) promotes glioma cell migration by enhancing the translation of RELA/p65

The diffusely infiltrative nature of glioblastoma (GBM) makes them highly recurrent. IGF2 mRNA-binding protein 3 (IMP3), a GBM upregulated RNA binding protein, promotes glioma cell migration. An integrative bioinformatics analysis identified p65 (RELA), a subunit of NF-κB heterodimer as a target and an important mediator of IMP3 promoted glioma cell migration. IMP3 increased p65 protein levels without any change in p65 transcript levels, but promoted its polysome association. RIP-PCR demonstrated the binding of IMP3 to p65 transcript. UV crosslinking experiments with in vitro transcribed RNA confirmed the specific and direct binding of IMP3 to sites on p65 3′UTR. Further, IMP3 induced luciferase activity from p65 3′UTR reporter carrying wild type sites but not mutated sites. Exogenous overexpression of p65 from a 3′UTR-less construct rescued the reduced migration of glioma cells in IMP3 silenced condition. In addition, IMP3 silencing inhibited glioma stem-like cell maintenance and migration. The exogenous overexpression of 3′UTR-less p65 significantly alleviated the inhibition of neurosphere formation observed in IMP3 silenced glioma stem-like cells. Further, we show that IMP3 is transcriptionally activated by NF-κB pathway indicating the presence of a positive feedback loop between IMP3 and p65. This study establishes p65 as a novel target of IMP3 in increasing glioma cell migration and underscores the significance of IMP3-p65 feedback loop for therapeutic targeting in GBM.

Loss-of-Function Mutations in Calcitonin Receptor (CALCR) Identify Highly Aggressive Glioblastoma with Poor Outcome

Purpose: Despite significant advances in the understanding of the biology, the prognosis of glioblastoma (GBM) remains dismal. The objective was to carry out whole-exome sequencing (WES) of Indian glioma and integrate with that of TCGA to find clinically relevant mutated pathways.Experimental Design: WES of different astrocytoma samples (n = 42; Indian cohort) was carried out and compared with that of TCGA cohort. An integrated analysis of mutated genes from Indian and TCGA cohorts was carried out to identify survival association of pathways with genetic alterations. Patient-derived glioma stem-like cells, glioma cell lines, and mouse xenograft models were used for functional characterization of calcitonin receptor (CALCR) and establish it as a therapeutic target.Results: A similar mutation spectrum between the Indian cohort and TCGA cohort was demonstrated. An integrated analysis identified GBMs with defective "neuroactive ligand-receptor interaction" pathway (n = 23; 9.54%) that have significantly poor prognosis (P < 0.0001). Furthermore, GBMs with mutated calcitonin receptor (CALCR) or reduced transcript levels predicted poor prognosis. Exogenously added calcitonin (CT) inhibited various properties of glioma cells and pro-oncogenic signaling pathways in a CALCR-dependent manner. Patient-derived mutations in CALCR abolished these functions with the degree of loss of function negatively correlating with patient survival. WT CALCR, but not the mutant versions, inhibited Ras-mediated transformation of immortalized astrocytes in vitro Furthermore, calcitonin inhibited patient-derived neurosphere growth and in vivo glioma tumor growth in a mouse model.Conclusions: We demonstrate CT-CALCR signaling axis is an important tumor suppressor pathway in glioma and establish CALCR as a novel therapeutic target for GBM. Clin Cancer Res; 24(6); 1448-58. ©2017 AACR.

IGF2 mRNA binding protein 3 (IMP3) mediated regulation of transcriptome and translatome in glioma cells

RNA binding proteins mediate global regulation at the level of transcriptome and translatome of a cell. We studied the global level expression changes regulated by IMP3 in transcriptome and translatome by performing microarray using total cellular RNA and heavy polysome derived RNA of IMP3 silenced glioma cells respectively. Differentially regulated transcripts at the transcriptome level (n = 2388) and at the level of translatome (n = 479) were identified. Further, these transcripts were classified as direct and indirect targets on the basis of presence of IMP3 binding site. Additional investigation revealed that direct targets at transcriptome level were found to be associated with processes related to cell cycle, whereas direct targets at the translatome level participated in apoptosis related pathways. Probable mechanism of indirect regulation at both the levels is also investigated. Collectively, our study reveals multi-level gene expression regulation imposed by IMP3 in glioma cells.

mRNA Traffic Control Reviewed: N6-Methyladenosine (m6 A) Takes the Driver's Seat

Messenger RNA is a flexible tool box that plays a key role in the dynamic regulation of gene expression. RNA modifications variegate the message conveyed by the mRNA. Similar to DNA and histone modifications, mRNA modifications are reversible and play a key role in the regulation of molecular events. Our understanding about the landscape of RNA modifications is still rudimentary in contrast to DNA and histone modifications. The major obstacle has been the lack of sensitive detection methods since they are non-editing events. However, with the advent of next-generation sequencing techniques, RNA modifications are being identified precisely at single nucleotide resolution. In recent years, methylation at the N6 position of adenine (m⁶ A) has gained the attention of RNA biologists. The m⁶ A modification has a set of writers (methylases), erasers (demethylases), and readers. Here, we provide a summary of interesting facts, conflicting findings, and recent advances in the technical and functional aspects of the m⁶ A epitranscriptome.

Elucidation of the genetic and epigenetic landscape alterations in RNA binding proteins in glioblastoma

RNA binding proteins (RBPs) have been implicated in cancer development. An integrated bioinformatics analysis of RBPs (n = 1756) in various datasets (n = 11) revealed several genetic and epigenetically altered events among RBPs in glioblastoma (GBM). We identified 13 mutated and 472 differentially regulated RBPs in GBM samples. Mutations in AHNAK predicted poor prognosis. Copy number variation (CNV), DNA methylation and miRNA targeting contributed to RBP differential regulation. Two sets of differentially regulated RBPs that may be implicated in initial astrocytic transformation and glioma progression were identified. We have also identified a four RBP (NOL3, SUCLG1, HERC5 and AFF3) signature, having a unique expression pattern in glioma stem-like cells (GSCs), to be an independent poor prognostic indicator in GBM. RBP risk score derived from the signature also stratified GBM into low-risk and high-risk groups with significant survival difference. Silencing NOL3, SUCLG1 and HERC5 inhibited GSC maintenance. Gene set enrichment analysis of differentially regulated genes between high-risk and low-risk underscored the importance of inflammation, EMT and hypoxia in high-risk GBM. Thus, we provide a comprehensive overview of genetic and epigenetic regulation of RBPs in glioma development and progression.

Abstract 2454: Genetic landscape of glioma reveals defective neuroactive ligand receptor interaction pathway as a poor prognosticator in glioblastoma patients

Glioblastoma (GBM; grade IV), is highly proliferative, infiltrative and treatment refractory. Hence, understanding the complete genetic alteration profile of GBM would help us in identifying molecules or pathways that have strong implications in GBM pathogenesis, thus opening up avenues for targeted therapy. Recent large scale studies suggest that three pathways - receptor-tyrosine kinase, TP53 and RB, are significantly altered in GBM. However, even with the tremendous increase in our understanding of the tumor, advancement in therapeutics is minimal and the median survival still remains at 15 months. Hence, we need to elucidate novel altered molecules and pathways in GBM progression such that more effective therapeutic options can be explored.

Here, we have carried out whole exome sequencing of grade II, grade III and GBM samples which revealed the mutation spectrum of glioma from our patient set. Further, we performed integrative analysis of mutated genes from our patient cohort as well as TCGA cohort (The Cancer Genome Atlas) to find out mutated pathways that predict survival in GBM patients. The most significant pathway - neuroactive ligand-receptor interaction pathway was explored further. Patients with mutations in one or more genes of this pathway had poor survival. The pathway comprises of G-protein coupled receptors, ion channels and ligands which functions in modulation of neural plasticity, memory processes, behavior etc. Of the enriched genes belonging to this pathway, Calcitonin Receptor (CALCR), which was highest mutated in GBM (2.75%), was taken up for further investigation. CALCR was found to be downregulated in GBM and mutation or downregulation of the gene was found to predict poor survival in patients. Functional studies through cell-line based experiments revealed CALCR is a tumor suppressor in GBM. The peptide hormone calcitonin (CT), a high affinity CALCR ligand, inhibited proliferation, migration and anchorage-independent growth of glioma cells expressing CALCR with a concomitant decrease in the phosphorylation levels of ERK, AKT and JNK signaling

molecules. However, CT failed to do these functions in CALCR silenced glioma cells. Exogenous overexpression of CALCR in glioma cells expressing low levels of the receptor was found to inhibit proliferation, migration and anchorage independent growth and this effect was further augmented when CT was added. Further, introduction of tumor-derived mutations in CALCR led to the abrogation of its tumor suppressor function. Studies are ongoing to demonstrate the tumor suppressive nature of CALCR using in vitro astrocyte transformation and intracranial orthotopic mouse glioma model. Thus, our study finds CT-CALCR signaling axis is an important tumor suppressor pathway in glioma development and underscores the importance of using CT as a novel therapeutic molecule for GBM treatment.

Citation Format: Jagriti Pal, Vikas Patil, Anupam Kumar, Kavneet Kaur, Chitra Sarkar, Kumaravel Somasundaram. Genetic landscape of glioma reveals defective neuroactive ligand receptor interaction pathway as a poor prognosticator in glioblastoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2454. doi:10.1158/1538-7445.AM2017-2454

Impact of somatic copy number alterations on the glioblastoma miRNome: miR-4484 is a genomically deleted tumour suppressor

Glioblastoma (GBM) is the most frequent and most malignant primary brain tumour in adults. GBMs have a unique landscape of somatic copy number alterations (SCNAs), with the concomitant appearance of numerous driver amplifications and deletions. Here, we examined the genomic regions harbouring SCNAs and their impact on the GBM miRNome. We found that 40% of SCNA events covering 70–88% of the genomically altered regions, as identified by GISTIC and RAE algorithms, carried miRNA genes. Of 1426 annotated mature miRNAs analysed, ~ 14% (n = 198) were mapped to such fragile loci. Further, we identified an intragenic miRNA, miR‐4484 located on chromosome‐10, as a deleted and downregulated miRNA in GBM. miR‐4484 exhibited a strong positive correlation with the expression of its host gene uroporphyrinogen III synthase (UROS), thereby indicating that the loss of miR‐4484 is a codeletion event in GBM. Overexpression of miR‐4484 reduced the colony‐forming ability and suppressed the migratory capacity of glioma cells. Analysis of the RNA‐seq‐derived transcriptome upon exogenous miR‐4484 overexpression in conjunction with an integrative bioinformatics approach revealed several putative targets of miR‐4484. Unbiased functional enrichment of these targets through DAVID identified a cohort of important gene ontology terms, which possibly explain the functional role of miR‐4484 in gliomagenesis. Selected targets were validated and, importantly, were found to be upregulated in GBM. In brief, our study identified a panel of miRNAs that are likely to be regulated by genomic deletions and amplifications. Further, miR‐4484 was found to be deleted and acts as a tumour suppressor miRNA in GBM.

DNA methylation signatures for 2016 WHO classification subtypes of diffuse gliomas

Background

Glioma is the most common of all primary brain tumors with poor prognosis and high mortality. The 2016 World Health Organization classification of the tumors of central nervous system uses molecular parameters in addition to histology to redefine many tumor entities. The new classification scheme divides diffuse gliomas into low-grade glioma (LGG) and glioblastoma (GBM) as per histology. LGGs are further divided into isocitrate dehydrogenase (IDH) wild type or mutant, which is further classified into either oligodendroglioma that harbors 1p/19q codeletion or diffuse astrocytoma that has an intact 1p/19q loci but enriched for ATRX loss and TP53 mutation. GBMs are divided into IDH wild type that corresponds to primary or de novo GBMs and IDH mutant that corresponds to secondary or progressive GBMs. To make the 2016 WHO subtypes of diffuse gliomas more robust, we carried out Prediction Analysis of Microarrays (PAM) to develop DNA methylation signatures for these subtypes.

Results

In this study, we applied PAM on a training set of diffuse gliomas derived from The Cancer Genome Atlas (TCGA) and identified DNA methylation signatures to classify LGG IDH wild type from LGG IDH mutant, LGG IDH mutant with 1p/19q codeletion from LGG IDH mutant with intact 1p/19q loci and GBM IDH wild type from GBM IDH mutant with an accuracy of 99–100%. The signatures were validated using the test set of diffuse glioma samples derived from TCGA with an accuracy of 96 to 99%. In addition, we also carried out additional validation of all three signatures using independent LGG and GBM cohorts. Further, the methylation signatures identified a fraction of samples as discordant, which were found to have molecular and clinical features typical of the subtype as identified by methylation signatures.

Conclusions

Thus, we identified methylation signatures that classified different subtypes of diffuse glioma accurately and propose that these signatures could complement 2016 WHO classification scheme of diffuse glioma.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0331-9) contains supplementary material, which is available to authorized users.

Biotin Decorated Gold Nanoparticles for Targeted Delivery of a Smart-Linked Anticancer Active Copper Complex: In Vitro and In Vivo Studies

The synthesis and anticancer activity of a copper(II) diacetyl-bis(N4-methylthiosemicarbazone) complex and its nanoconjugates are reported. The copper(II) complex is connected to a carboxylic acid group through a cleavable disulfide link to enable smart delivery. The copper complex is tethered to highly water-soluble 20 nm gold nanoparticles (AuNPs), stabilized by amine terminated lipoic acid-polyethylene glycol (PEG). The gold nanoparticle carrier was further decorated with biotin to achieve targeted action. The copper complex and the conjugates with and without biotin, were tested against HeLa and HaCaT cells. They show very good anticancer activity against HeLa cells, a cell line derived from cervical cancer and are less active against HaCaT cells. Slow and sustained release of the complex from conjugates is demonstrated through cleavage of disulfide linker in the presence of glutathione (GSH), a reducing agent intrinsically present in high concentrations within cancer cells. Biotin appended conjugates do not show greater activity than conjugates without biotin against HeLa cells. This is consistent with drug uptake studies, which suggests similar uptake profiles for both conjugates in vitro. However, in vivo studies using a HeLa cell xenograft tumor model shows 3.8-fold reduction in tumor volume for the biotin conjugated nanoparticle compared to the control whereas the conjugate without biotin shows only 2.3-fold reduction in the tumor volume suggesting significant targeting.

PI3 kinase pathway regulated miRNome in glioblastoma: identification of miR-326 as a tumour suppressor miRNA

Background

Glioblastomas (GBM) continue to remain one of the most dreaded tumours that are highly infiltrative in nature and easily preclude comprehensive surgical resection. GBMs pose an intricate etiology as they are being associated with a plethora of genetic and epigenetic lesions. Misregulation of the PI3 kinase pathway is one of the most familiar events in GBM. While the PI3 kinase signalling regulated pathways and genes have been comprehensively studied, its impact on the miRNome is yet to be explored. The objective of this study was to elucidate the PI3 kinase pathway regulated miRNAs in GBM.

Methods

miRNA expression profiling was conducted to monitor the differentially regulated miRNAs upon PI3 kinase pathway abrogation. qRT-PCR was used to measure the abundance of miR-326 and its host gene encoded transcript. Proliferation assay, colony suppression assay and wound healing assay were carried out in pre-miR transfected cells to investigate its role in malignant transformation. Potential targets of miR-326 were identified by transcriptome analysis of miR-326 overexpressing cells by whole RNA sequencing and selected targets were validated. Several publically available data sets were used for various investigations described above.

Results

We identified several miRNA that were regulated by PI3 kinase pathway. miR-326, a GBM downregulated miRNA, was validated as one of the miRNAs whose expression was alleviated upon abrogation of the PI3 kinase pathway. Overexpression of miR-326 resulted in reduced proliferation, colony suppression and hindered the migration capacity of glioma cells. Arrestin, Beta 1 (ARRB1), the host gene of miR-326, was also downregulated in GBM and interestingly, the expression of ARRB1 was also alleviated upon inhibition of the PI3 kinase pathway, indicating similar regulation pattern. More importantly, miR-326 exhibited a significant positive correlation with ARRB1 in terms of its expression. Transcriptome analysis upon miR-326 overexpression coupled with integrative bioinformatics approach identified several putative targets of miR-326. Selected targets were validated and interestingly found to be upregulated in GBM.

Conclusions

Taken together, our study uncovered the PI3 kinase regulated miRNome in GBM. miR-326, a PI3 kinase pathway inhibited miRNA, was demonstrated as a tumour suppressor miRNA in GBM.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0557-8) contains supplementary material, which is available to authorized users.

Elucidating the cancer-specific genetic alteration spectrum of glioblastoma derived cell lines from whole exome and RNA sequencing

Cell lines derived from tumor tissues have been used as a valuable system to study gene regulation and cancer development. Comprehensive characterization of the genetic background of cell lines could provide clues on novel genes responsible for carcinogenesis and help in choosing cell lines for particular studies. Here, we have carried out whole exome and RNA sequencing of commonly used glioblastoma (GBM) cell lines (U87, T98G, LN229, U343, U373 and LN18) to unearth single nucleotide variations (SNVs), indels, differential gene expression, gene fusions and RNA editing events. We obtained an average of 41,071 SNVs out of which 1,594 (3.88%) were potentially cancer-specific. The cell lines showed frequent SNVs and indels in some of the genes that are known to be altered in GBM- EGFR, TP53, PTEN, SPTA1 and NF1. Chromatin modifying genes- ATRX, MLL3, MLL4, SETD2 and SRCAP also showed alterations. While no cell line carried IDH1 mutations, five cell lines showed hTERT promoter activating mutations with a concomitant increase in hTERT transcript levels. Five significant gene fusions were found of which NUP93-CYB5B was validated. An average of 18,949 RNA editing events was also obtained. Thus we have generated a comprehensive catalogue of genetic alterations for six GBM cell lines.

Epigenetically silenced GNG4 inhibits SDF1α/CXCR4 signaling in mesenchymal glioblastoma

The most common and aggressive form of primary brain tumor in adults is glioblastoma (GBM). From the global DNA methylation profiling study, previously published from our laboratory, we identified Guanine Nucleotide binding-protein Gamma subunit 4 (GNG4) to be one of the most hyper methylated and down regulated genes in GBM. GBM derived cell lines showed reduced GNG4 transcript levels, which could be reversed by methylation inhibitor treatment. Bisulphite sequencing confirmed the methylation status in glioblastoma tumor tissue and GBM derived cell lines. Overexpression of GNG4 was found to inhibit proliferation and colony formation of GBM cell lines and in vitro transformation of immortalized human astrocytes, thus suggesting a potential tumor suppressor role of GNG4 in GBM. Correlation of GNG4 transcript levels with that of all GPCRs from TCGA data revealed chemokine receptors as the potential target of GNG4. Furthermore, exogenous over expression of GNG4 inhibited SDF1α/CXCR4-dependent chemokine signaling as seen by reduced pERK and pJNK and GBM cell migration. The inhibitory association between GNG4 and SDF1α/CXCR4 was more evident in mesenchymal subtype of GBM. Thus, this study identifies GNG4 as an inhibitor of SDF1α/CXCR4-dependent signaling and emphasizes the significance of epigenetic inactivation of GNG4 in glioblastoma, especially in mesenchymal subtype.

Raman and infra-red microspectroscopy: towards quantitative evaluation for clinical research by ratiometric analysis

We demonstrate how ratioing spectral bands can circumvent experimental artefacts, and present a library of ratios from the biomedical literature.

An Eighteen Serum Cytokine Signature for Discriminating Glioma from Normal Healthy Individuals

Glioblastomas (GBM) are largely incurable as they diffusely infiltrate adjacent brain tissues and are difficult to diagnose at early stages. Biomarkers derived from serum, which can be obtained by minimally invasive procedures, may help in early diagnosis, prognosis and treatment monitoring. To develop a serum cytokine signature, we profiled 48 cytokines in sera derived from normal healthy individuals (n = 26) and different grades of glioma patients (n = 194). We divided the normal and grade IV glioma/GBM serum samples randomly into equal sized training and test sets. In the training set, the Prediction Analysis for Microarrays (PAM) identified a panel of 18 cytokines that could discriminate GBM sera from normal sera with maximum accuracy (95.40%) and minimum error (4.60%). The 18-cytokine signature obtained in the training set discriminated GBM sera from normal sera in the test set as well (accuracy 96.55%; error 3.45%). Interestingly, the 18-cytokine signature also differentiated grade II/Diffuse Astrocytoma (DA) and grade III/Anaplastic Astrocytoma (AA) sera from normal sera very efficiently (DA vs. normal–accuracy 96.00%, error 4.00%; AA vs. normal–accuracy 95.83%, error 4.17%). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using 18 cytokines resulted in the enrichment of two pathways, cytokine-cytokine receptor interaction and JAK-STAT pathways with high significance. Thus our study identified an 18-cytokine signature for distinguishing glioma sera from normal healthy individual sera and also demonstrated the importance of their differential abundance in glioma biology.

Glioblastoma-derived Macrophage Colony-stimulating Factor (MCSF) Induces Microglial Release of Insulin-like Growth Factor-binding Protein 1 (IGFBP1) to Promote Angiogenesis

Glioblastoma (grade IV glioma/GBM) is the most common primary adult malignant brain tumor with poor prognosis. To characterize molecular determinants of tumor-stroma interaction in GBM, we profiled 48 serum cytokines and identified macrophage colony-stimulating factor (MCSF) as one of the elevated cytokines in sera from GBM patients. Both MCSF transcript and protein were up-regulated in GBM tissue samples through a spleen tyrosine kinase (SYK)-dependent activation of the PI3K-NFκB pathway. Ectopic overexpression and silencing experiments revealed that glioma-secreted MCSF has no role in autocrine functions and M2 polarization of macrophages. In contrast, silencing expression of MCSF in glioma cells prevented tube formation of human umbilical vein endothelial cells elicited by the supernatant from monocytes/microglial cells treated with conditioned medium from glioma cells. Quantitative proteomics based on stable isotope labeling by amino acids in cell culture showed that glioma-derived MCSF induces changes in microglial secretome and identified insulin-like growth factor-binding protein 1 (IGFBP1) as one of the MCSF-regulated proteins secreted by microglia. Silencing IGFBP1 expression in microglial cells or its neutralization by an antibody reduced the ability of supernatants derived from microglial cells treated with glioma cell-conditioned medium to induce angiogenesis. In conclusion, this study shows up-regulation of MCSF in GBM via a SYK-PI3K-NFκB-dependent mechanism and identifies IGFBP1 released by microglial cells as a novel mediator of MCSF-induced angiogenesis, of potential interest for developing targeted therapy to prevent GBM progression.

Definition of a serum marker panel for glioblastoma discrimination and identification of Interleukin 1β in the microglial secretome as a novel mediator of endothelial cell survival induced by C-reactive protein

Glioblastoma (GBM) is the most common malignant adult primary brain tumor. We profiled 724 cancer-associated proteins in sera of healthy individuals (n=27) and GBM (n=28) using antibody microarray. While 69 proteins exhibited differential abundance in GBM sera, a three-marker panel (LYAM1, BHE40 and CRP) could discriminate GBM sera from that of healthy donors with an accuracy of 89.7% and p<0.0001. The high abundance of C-reactive protein (CRP) in GBM sera was confirmed in 264 independent samples. High levels of CRP protein was seen in GBM but without a change in transcript levels suggesting a non-tumoral origin. Glioma-secreted Interleukin 6 (IL6) was found to induce hepatocytes to secrete CRP, involving JAK-STAT pathway. The culture supernatant from CRP-treated microglial cells induced endothelial cell survival under nutrient-deprivation condition involving CRP-FcγRIII signaling cascade. Transcript profiling of CRP-treated microglial cells identified Interleukin 1β (IL1β) present in the microglial secretome as the key mediator of CRP-induced endothelial cell survival. IL1β neutralization by antibody-binding or siRNA-mediated silencing in microglial cells reduced the ability of the supernatant from CRP-treated microglial cells to induce endothelial cell survival. Thus our study identifies a serum based three-marker panel for GBM diagnosis and provides leads for developing targeted therapies. Biological significance A complex antibody microarray based serum marker profiling identified a three-marker panel - LYAM1, BHE40 and CRP as an accurate discriminator of glioblastoma sera from that of healthy individuals. CRP protein is seen in high levels without a concomitant increase of CRP transcripts in glioblastoma. Glioma-secreted IL6 induced hepatocytes to produce CRP in a JAK-STAT signaling dependent manner. CRP induced microglial cells to release IL1β which in turn promoted endothelial cell survival. This study, besides defining a serum panel for glioblastoma discrimination, identified IL1β as a potential candidate for developing targeted therapy.

Therapeutic potential of an adenovirus expressing p73beta, a p53 homologue, against human papilloma virus positive cervical cancer in vitro and in vivo

Human papilloma virus (HPV) infection is the most important risk factor for cervical cancer development. p53 based gene therapy is not suitable for cervical cancer because HPV oncoprotein E6 inactivates p53 protein by targeting it for ubiquitin mediated degradation. Here we evaluated the efficiency of Ad-p73, a replication deficient adenovirus expressing p73beta a p53 homologue, to inhibit the growth of HPV positive cervical cancer cells in vitro using tissue culture system and in vivo using human xenografts in nude mice. Ad-p73, but not Ad-p53 (p53 adenovirus), inhibited the growth in vitro of three different HPV positive cervical cancer cell lines, HeLa, ME180, and SiHa, efficiently, which correlated with stable expression of functional p73 protein. However, the growth of a HPV negative cervical cancer cell line, C33A, was inhibited equally by both Ad-p73 and Ad-p53. In addition, we show that Ad-p73 preinfected HeLa cells and HCT116 E6 cells, an E6 stable cell line, failed to form tumors in nude mice unlike Ad-p53 or Ad-LacZ preinfected cells. Moreover, Ad-p73, but not Ad-p53, inhibited completely the growth of already established tumors of HeLa or HCT116 E6 cells. Furthermore, the ability of p73 to inhibit the growth of these tumors correlated with the stable expression of p73 protein with the concomitant induction of its target gene p21(WAF1/CIP1) and induction of apoptosis in tumor cells. These results suggest that Ad-p73 inhibits efficiently the growth in vitro and tumorigenicity and tumor growth in vivo of HPV positive cervical cancer cells and that p73-based approach should be explored as a potential therapeutic model for the treatment of cervical cancer.

Genome-wide methylation profiling identifies an essential role of reactive oxygen species in pediatric glioblastoma multiforme and validates a methylome specific for H3 histone family 3A with absence of G-CIMP/isocitrate dehydrogenase 1 mutation

BACKGROUND

Pediatric glioblastoma multiforme (GBM) is rare, and there is a single study, a seminal discovery showing association of histone H3.3 and isocitrate dehydrogenase (IDH)1 mutation with a DNA methylation signature. The present study aims to validate these findings in an independent cohort of pediatric GBM, compare it with adult GBM, and evaluate the involvement of important functionally altered pathways.

METHODS

Genome-wide methylation profiling of 21 pediatric GBM cases was done and compared with adult GBM data (GSE22867). We performed gene mutation analysis of IDH1 and H3 histone family 3A (H3F3A), status evaluation of glioma cytosine-phosphate-guanine island methylator phenotype (G-CIMP), and Gene Ontology analysis. Experimental evaluation of reactive oxygen species (ROS) association was also done.

RESULTS

Distinct differences were noted between methylomes of pediatric and adult GBM. Pediatric GBM was characterized by 94 hypermethylated and 1206 hypomethylated cytosine-phosphate-guanine (CpG) islands, with 3 distinct clusters, having a trend to prognostic correlation. Interestingly, none of the pediatric GBM cases showed G-CIMP/IDH1 mutation. Gene Ontology analysis identified ROS association in pediatric GBM, which was experimentally validated. H3F3A mutants (36.4%; all K27M) harbored distinct methylomes and showed enrichment of processes related to neuronal development, differentiation, and cell-fate commitment.

CONCLUSIONS

Our study confirms that pediatric GBM has a distinct methylome compared with that of adults. Presence of distinct clusters and an H3F3A mutation-specific methylome indicate existence of epigenetic subgroups within pediatric GBM. Absence of IDH1/G-CIMP status further indicates that findings in adult GBM cannot be simply extrapolated to pediatric GBM and that there is a strong need for identification of separate prognostic markers. A possible role of ROS in pediatric GBM pathogenesis is demonstrated for the first time and needs further evaluation.

Methylation silencing of ULK2, an autophagy gene, is essential for astrocyte transformation and tumor growth

Glioblastoma (GBM) is the most aggressive type of brain tumor and shows very poor prognosis. Here, using genome-wide methylation analysis, we show that G-CIMP+ and G-CIMP-subtypes enrich distinct classes of biological processes. One of the hypermethylated genes in GBM, ULK2, an upstream autophagy inducer, was found to be down-regulated in GBM. Promoter hypermethylation of ULK2 was confirmed by bisulfite sequencing. GBM and glioma cell lines had low levels of ULK2 transcripts, which could be reversed upon methylation inhibitor treatment. ULK2 promoter methylation and transcript levels showed significant negative correlation. Ectopic overexpression of ULK2-induced autophagy, which further enhanced upon nutrient starvation or temozolomide chemotherapy. ULK2 also inhibited the growth of glioma cells, which required autophagy induction as kinase mutant of ULK2 failed to induce autophagy and inhibit growth. Furthermore, ULK2 induced autophagy and inhibited growth in Ras-transformed immortalized Baby Mouse Kidney (iBMK) ATG5(+/+) but not in autophagy-deficient ATG5(-/-) cells. Growth inhibition due to ULK2 induced high levels of autophagy under starvation or chemotherapy utilized apoptotic cell death but not at low levels of autophagy. Growth inhibition by ULK2 also appears to involve catalase degradation and reactive oxygen species generation. ULK2 overexpression inhibited anchorage independent growth, inhibited astrocyte transformation in vitro and tumor growth in vivo. Of all autophagy genes, we found ULK2 and its homologue ULK1 were only down-regulated in all grades of glioma. Thus these results altogether suggest that inhibition of autophagy by ULK1/2 down-regulation is essential for glioma development.

A 16-gene signature distinguishes anaplastic astrocytoma from glioblastoma

Anaplastic astrocytoma (AA; Grade III) and glioblastoma (GBM; Grade IV) are diffusely infiltrating tumors and are called malignant astrocytomas. The treatment regimen and prognosis are distinctly different between anaplastic astrocytoma and glioblastoma patients. Although histopathology based current grading system is well accepted and largely reproducible, intratumoral histologic variations often lead to difficulties in classification of malignant astrocytoma samples. In order to obtain a more robust molecular classifier, we analysed RT-qPCR expression data of 175 differentially regulated genes across astrocytoma using Prediction Analysis of Microarrays (PAM) and found the most discriminatory 16-gene expression signature for the classification of anaplastic astrocytoma and glioblastoma. The 16-gene signature obtained in the training set was validated in the test set with diagnostic accuracy of 89%. Additionally, validation of the 16-gene signature in multiple independent cohorts revealed that the signature predicted anaplastic astrocytoma and glioblastoma samples with accuracy rates of 99%, 88%, and 92% in TCGA, GSE1993 and GSE4422 datasets, respectively. The protein-protein interaction network and pathway analysis suggested that the 16-genes of the signature identified epithelial-mesenchymal transition (EMT) pathway as the most differentially regulated pathway in glioblastoma compared to anaplastic astrocytoma. In addition to identifying 16 gene classification signature, we also demonstrated that genes involved in epithelial-mesenchymal transition may play an important role in distinguishing glioblastoma from anaplastic astrocytoma.