Association of Circadian Clock Gene Expression with Glioma Tumor Microenvironment and Patient Survival

Circadian clock genes have been linked to clinical outcomes in cancer, including gliomas. However, these studies have not accounted for established markers that predict the prognosis, including mutations in Isocitrate Dehydrogenase (IDH), which characterize the majority of lower-grade gliomas and secondary high-grade gliomas. To demonstrate the connection between circadian clock genes and glioma outcomes while accounting for the IDH mutational status, we analyzed multiple publicly available gene expression datasets. The unsupervised clustering of 13 clock gene transcriptomic signatures from The Cancer Genome Atlas showed distinct molecular subtypes representing different disease states and showed the differential prognosis of these groups by a Kaplan–Meier analysis. Further analyses of these groups showed that a low period (PER) gene expression was associated with the negative prognosis and enrichment of the immune signaling pathways. These findings prompted the exploration of the relationship between the microenvironment and clock genes in additional datasets. Circadian clock gene expression was found to be differentially expressed across the anatomical tumor location and cell type. Thus, the circadian clock expression is a potential predictive biomarker in glioma, and further mechanistic studies to elucidate the connections between the circadian clock and microenvironment are warranted.

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TAMI-44. ASSOCIATION OF CIRCADIAN CLOCK GENE EXPRESSION WITH GLIOMA TUMOR MICROENVIRONMENT AND PATIENT SURVIVAL

Neuro-Oncology ◽

10.1093/neuonc/noab196.827 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi207-vi207

Author(s):

Julianie De La Cruz Minyety ◽

Dorela Shuboni-Mulligan ◽

Nicole Briceno ◽

Demarrius Young Jr. ◽

Mark Gilbert ◽

...

Keyword(s):

Gene Expression ◽

Circadian Clock ◽

Clock Gene ◽

Clock Genes ◽

Cell Types ◽

The Cancer Genome Atlas ◽

Wild Type ◽

Clock Gene Expression ◽

Mutational Status ◽

Circadian Clock Genes

Abstract Circadian clock genes have been linked to differences in clinical outcomes in cancer, including gliomas. However, these studies have not accounted for established prognostic markers, including mutations in Isocitrate Dehydrogenase (IDH). To study the connection between circadian clock genes and glioma outcomes while accounting for IDH mutational status, we analyzed multiple publicly available gene expression datasets. Unsupervised clustering of 13 clock gene transcriptomic signatures from The Cancer Genome Atlas resulted in four distinct transcriptomic clusters, two clusters were enriched for IDH mutant (Circadian 1-2) and the others for IDH wild-type gliomas (Circadian 3-4). Within these clusters we observed differential prognosis of the patients by Kaplan–Meier analysis (Circadian 1-2, p=0.0001; Circadian 3-4, p=0.0002) suggesting that these transcriptomic circadian subtypes might reflect different disease states. Further analyses using Cox Proportional Hazards Regression showed that lower Period (PER) gene expression was associated with worse prognosis (increasing PER expression HR=0.655, p=0.007) independent of IDH wild-type status (HR=5.312, p< 0.001) and increasing age (HR = 1.04, p< 0.001). Lower PER expression was associated with enrichment of a number of immune signaling pathways. These findings prompted the exploration of the relationship between microenvironment and clock genes using the Ivy GAP dataset to explore tumor location-specific differences and single cell RNA sequencing data from Darmanis (accession: GSE84465) to explore cell-specific differences. Circadian clock genes were found to be differentially expressed across anatomical tumor locations and cell types, including microglia. In ongoing studies we are examining the role of the microenvironment and PER2 expression on tumor growth by disrupting PER2 expression in tumor cells and microglia using IDH mutant and wild-type in vitro models. Clock gene expression is a potential prognostic biomarker in glioma and further studies to elucidate the importance of circadian rhythms in other cell types beyond the tumor are warranted.

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Differential Expression of Circadian Clock Genes in the Bovine Neuroendocrine Adrenal System

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.134 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A66-A67

Author(s):

Audrey L Earnhardt ◽

David G Riley ◽

Noushin Ghaffari ◽

Penny K Riggs ◽

Charles R Long ◽

...

Keyword(s):

Gene Expression ◽

Circadian Clock ◽

Clock Gene ◽

Target Genes ◽

Clock Genes ◽

Expression Profiles ◽

Primary Objective ◽

Clock Gene Expression ◽

Adrenal System ◽

Circadian Clock Genes

Abstract The primary objective of this investigation was to determine whether circadian clock genes were differentially expressed within or among bovine hypothalamic paraventricular nucleus (PVN), anterior pituitary gland (AP), adrenocortical (AC) and adrenomedullary (AM) tissues. The PVN, AP, AC, and AM were isolated from 5-yr-old Brahman cows (n = 8) harvested humanely at an abattoir between 0800-1100 h. Expression of target genes in each sample was evaluated via RNA-sequencing analyses. Gene counts were normalized using the trimmed mean of M values (TMM) method in the edgeR Package from Bioconductor, R. The normalized gene counts of genes important for circadian rhythm were statistically analyzed using the GLM Procedure of SAS. The genes analyzed were circadian locomotor output cycles protein kaput (CLOCK), cryptochrome circadian regulator 1 and 2 (CRY1 and CRY2), aryl hydrocarbon receptor nuclear translocator like (ARNTL), period circadian regulator 1 and 2 (PER1 and PER2), neuronal PAS domain protein 2 (NPAS2), and nuclear receptor subfamily 1 group D member 1 (NR1D1). Overall, relative expression profiles of clock genes differed (P < 0.01) within each tissue with PER1 having greater expression in all tissues (P < 0.01). Within the PVN expression of CLOCK, CRY1, ARNTL, and PER2 was less than that of CRY2, NPAS2, and NR1D1 (P < 0.01). In the AP, with the exception of PER1, no other clock gene differed in degree of expression. In the AC, expression of CLOCK and NPAS2 was greater than CRY1, ARNTL, PER2, and NR1D1 (P < 0.05), whereas CRY2 expression exceeded only CRY1 (P < 0.05). Within the AM, CLOCK and CRY2 expression was greater than CRY1 and ARNTL (P < 0.05). Overall, clock gene expression among tissues differed (P < 0.01) for each individual clock gene. The AC and AM had similar clock gene expression, except expression of CRY2 and PER2 was greater in AM (P < 0.05). The AC and AM had greater expression of CLOCK than the PVN and AP (P < 0.01), with PVN having greater expression than AP (P < 0.01). The AP had greater expression of NPAS2, followed by PVN, with the least expression in the AC and AM (P < 0.01). Both PVN and AP had greater CRY1 and NR1D1 expression than AC or AM (P < 0.01). The AP had greater PER1 expression than PVN, AC, and AM (P < 0.01), whereas PVN, AC, and AM had greater ARNTL expression than AP (P < 0.05). Both AP and AM had greater expression of PER2 than PVN or AC (P < 0.01). The PVN had greater expression of CRY2 than the AP, AC, and AM (P < 0.01). These results indicated that within each tissue the various clock genes were expressed in different quantities. Also, the clock genes were expressed differentially among the tissues of the bovine neuroendocrine adrenal system. Temporal relationships of these genes with the primary endocrine products of these tissues should be investigated to define the roles of peripheral clock genes in regulation of metabolism and health.

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