The Effects Of Glucocorticoids On Suppressing Tumor Independently Of Receptor

Glucocorticoids(GCs)has been widely used to treat chemotherapy-induced nausea and vomiting or to control immunotherapy-related adverse events(ir AEs)in clinical practice.Previously,GCs were shown to have a powerful inhibitory effect on the immune system,while the inhibition of immune response seems to be contrary to GCs applied in clinical cancer treatment.Previously,GCs can regulate genome activities mainly through Glucocorticoid receptor(GR),but the mechanism of GCs on tumor progression with or without GR remains unclear.Therefore,to clarify the underlying mechanisms of DEX in tumor progression in immunocompetent or immune activated organism were necessary.In vivo assays,immunoblotting and q PCR assays were used to explore the underlying molecular mechanism of DEX in tumor progression in immunocompetent or immune activated tumor-bearing mice,and to determine the effect of DEX on tumor cell and immune cells,especially Th1and CD8⁺T cells in tumor microenvironment.To elucidate the effect of DEX on tumor progression and the potential molecular mechanism in a GR-independent manner,we further constructed Sh-GR and Sg-GR stable cell lines,and used CCK8 assay,tumor formation measured assay,q PCR,and RNA seq to investigate the model of action and the underlying mechanisms of DEX in tumor progression.RNA-seq data showed that treatment with DEX significantly inhibit immunoglobulin heavy or light chain variable region genes(IGH(L)Vs)expression in C57BL/6 mice,which further indicated a potent immunosuppressive function.As the DEX concentration increased,the tumor volume markedly decreased,the survival time increased,the expression of cell proliferation markers Ki67 and C-myc decreased,and the expression of cell apoptosis marker cleaved caspase 3increased in immunocompetent tumor-bearing mice,especially for the high dose DEX injected group.PD-1H,a new immune checkpoint belong to CD28-B7 family,which could inhibit T cell activation.In PD-1H KO immune activated tumor-bearing mice,the tumor volume and the expression of the cell proliferation markers Ki67 were markedly decreased,however,the tumor progression was further inhibited in response to high-dose DEX.Results showed that some genes associated with the recruitment,presence,and function of Th1 cells and CD8⁺T cells were significantly downregulated following treatment with DEX e.g.,Cxcl9,Cxcl10,Cd3e,Gzmb,Ifng in immunocompetent or immune activated tumor-bearing mice.DEX treatment significantly decreased the expression of glucose and lipid metabolic pathway-related genes e.g.,Glut1,Idh3a,Gpam,Agpat2,Dgat1,Cpt1a,Pnpla2,Fabp1 in immunocompetent or immune activated tumor-bearing mice.These findings were further confirmed in vitro.Besides,increased serum glucose and decreased serum TG and non-esterified fatty acid(NEFA)were observed in DEX treated-xenografted tumor mice.Results further showed that DEX inhibited tumor progression in a GR independent manner in vitro and in vivo.Treatment with DEX significantly increased the expression of genes(Klf9,Snai2,Vim)in a GR independent manner.RNA seq data showed that DEX inhibited tumor progression may associated with glucose and lipid metabolism in a GR independent manner.q PCR analyzed and showed that treatment with DEX significantly inhibit the transcription level of important genes association with glucose and lipid metabolism in Sh-CTL LLC cells.Treatment with DEX significantly inhibited the m RNA levels of genes associated with glucose and lipid metabolism such as Glut1,Hk2,Dgat1 and Cpt1a,but not Idh3a,Agpat2,Fabp1,Slc27a4 and Acadm,which indicated DEX could affect glucose and lipid metabolism in a GR independent manner.RNA seq analyzed showed that DEX inhibited tumor progression may associated with TNF signaling pathway,Ca²⁺signaling pathway,PPAR signaling pathway in a GR independent manner.Here,we propose hypothesis to explain the inhibition of tumor progression.Based on these results,we conclude that DEX-inhibited tumor progression associated with the uptake and consumption of glucose and lipids defeciency,TNF signaling pathway,PPAR signaling pathway and Ca²⁺signaling pathway in a GR independent manner.