Rewiring of Lactate–Interleukin-1β Autoregulatory Loop with Clock-Bmal1: a Feed-Forward Circuit in Glioma

Abstract

De-synchronized circadian rhythm in tumors is coincident with aberrant inflammation and dysregulated metabolism. As their inter-relationship in cancer etiology is largely unknown, we investigated the link between the three in glioma. Tumor metabolite lactate- mediated increase in pro-inflammatory cytokine IL-1β was concomitant with elevated levels of core circadian regulators Clock and Bmal1. siRNA mediated knockdown of Bmal1 and Clock decreased (i) LDHA and IL-1β levels and (ii) release of lactate and pro-inflammatory cytokines. Lactate mediated deacetylation of Bmal1 and its interaction with Clock, regulate IL-1β levels and vice versa. Site-directed mutagenesis and luciferase reporter assay indicated the functionality of E-box sites on LDHA and IL-1β promoters. ChIP-re-ChIP revealed that lactate-IL-1β crosstalk positively affects co-recruitment of Clock-Bmal1 to these E-box sites. Clock-Bmal1 enrichment was accompanied by decreased H3K9me3, and increased H3K9ac and RNA pol II occupancy. Lactate-IL-1β-Clock (LIC) loop positively regulated expression of genes associated with cell cycle, DNA damage and cytoskeletal organization involved in glioma progression. TCGA data analysis suggested the presence of lactate- IL-1β-crosstalk in other cancers. The responsiveness of stomach and cervical cancer cells to lactate inhibition followed the same trend exhibited by glioma cells. In addition, components of LIC loop were found to be correlated with (i) patient survival, (ii) clinically actionable genes, and (iii) anti-cancer drug sensitivity. Our findings provide evidence for a potential cancer-specific axis wiring of IL-1β and LDHA through Clock -Bmal1, the outcome of which is to fuel an IL-1β-lactate autocrine loop that drives pro-inflammatory and oncogenic signals.

Cell-type specific profiling of histone post-translational modifications in the adult mouse striatum

“…While ICuRuS can determine H3K4me3/H3K27me3 coenrichment at specific loci, it cannot determine if these marks occur on the same histone or nucleosome. An alternative approach to study H3K4me3/H3K27me3 bivalency is sequential ChIP, which determines hPTM localization on the same nucleosome 45 . Overall, ICuRuS provides technological advances to understand epigenetic regulation in other neural disorders, brain regions, and cell-types A2a and D1 MSNs make up ~95% of the neuronal population in the striatum 46 .…”

Molecular mechanisms of tumour development in glioblastoma: an emerging role for the circadian clock

“…In more detail, CLOCK increased the expression of cyclins A, B1 , and D1 due to its histone transferase activity and activated the NF-κB (Nuclear Factor kappa B) pathway. Its expression was de-repressed in GBM by downregulation of miR-124 (microRNA-124) 17 , 19 . Notably, a study performed by Dong et al found that downregulation of CLOCK/BMAL1 negatively affected proliferation and cell cycle progression in Glioblastoma Stem Cells (GSCs) but not in Neural Stem Cells (NSCs) 16 .…”

“…3b ). The function of CLOCK/BMAL1 in oxidative stress regulation and DNA damage repair under normal conditions i.e., without external stress induction is controversial in experimental studies 17 , 19 – 21 . In a computational study using TCGA (The Cancer Genome Atlas) glioma data, CRY1 , BMAL1 , and RORγ were associated with a higher mutation rate and mutation hotspots in EGFR , TTN (Titin) , and PTEN (Phosphatase and Tensin Homologue) genes.…”

Insights about circadian clock in glioma: From molecular pathways to therapeutic drugs

“…A desynchronized circadian rhythm in tumors is coincident with aberrant inflammation and dysregulated metabolism 105 . The increase in tumor metabolite lactate results in the cytokine interleukin‐1β (IL‐1β) upregulation leading to inflammatory 106 . IL‐1β was correlated with elevated levels of the core circadian regulators Clock and Bmal1 106 .…”

“…The increase in tumor metabolite lactate results in the cytokine interleukin‐1β (IL‐1β) upregulation leading to inflammatory 106 . IL‐1β was correlated with elevated levels of the core circadian regulators Clock and Bmal1 106 . Lactate‐IL‐1β interaction positively affects the recruitment of CLOCK: BMAL1 to these E‐box sites in the nucleus 107 .…”