The critical role of protein disequilibrium in driving carcinogenesis has long been recognized. Though several inhibitors of heat shock protein (HSP) family members have entered clinical trials, none of them have been approved for clinical use as a result of inevitable toxicity, leading to the identification of safer therapeutic approaches sharing a similar efficacy relevant and urgent. Through delineating the role of HSP90 inhibitors in arresting cancer hallmarks, this paper identified HSP90 inhibition as an effective therapeutic strategy capable of concomitantly targeting multiple key transformed properties of cancers via modulating cellular proteostasis. Through interrogating intrinsic connections between proteostasis and redox homeostasis, this paper proposed cold atmospheric plasma (CAP) as a possible alternative of HSP90 inhibitors with little adverse effects. This paper extended the therapeutic spectrum of HSP90 inhibitors and CAP to inflammation-driven pathologies including autoimmune diseases, as inflammation is a manifestation of failed proteostasis. These insights may conceptually advance our understandings on the driving force of cancers that can be easily extended to other disorders originated from imbalanced proteostasis and abnormal inflammation. Tools proposed here for inhibiting HSP90 including CAP and its possible synergy with HSP90 inhibitors may shift the current treatment paradigm to a new avenue in oncology and other relevant fields.

Objective To investigate the influence of early growth response gene-1 (EGR1) on the autophagy of host cells following infection with human T cell leukemia virus type 1 (HTLV-1).MethodsA HTLV-1-positive cell line MT2 was co-cultured with HeLa cells for 24 h to construct the virus early infection model.Immunoblotting assay was used to detect the expression of HTLV-1 core protein p19 and EGR1.Luciferase reporter gene analysis was used to detect the transcriptional activity of 5′-regulatory sequence of EGR1 at different time points after co-culturing.An effective small interfering RNA (siRNA) targeting EGR1 was screened out and transfected into HeLa cells by Lipofectamine 2000.Then the transfected HeLa cells were co-cultured with the HTLV-1-positive cell line MT2 for 24 h.Immunoblotting assay was used to detect HTLV-1 core protein p19, EGR1 and autophagy-related protein LC3.Real-time PCR was performed to detect viral load.Autophagosome was analyzed by immunofluorescence after co-culturing.Results The expression of EGR1 and the transcriptional activity of pEGR1-luc gradually increased after co-culturing HeLa cells with MT2 cells for 8 h (P<0.01).The expression of EGR1 was positively correlated with host cell autophagy following HTLV-1 infection.The effective siRNA for silencing the expression of EGR1 was obtained and named as siE2.The viral load, the expression of HTLV-1 core protein p19 and the proportion of LC3B/LC3A in the co-culture model were markedly down-regulated by RNA interference with siE2, which was concomitant with a persistent decrease of intracellular autophagosome (P<0.01).Conclusion EGR1 is associated with host cell autophagy and viral replication in HTLV-1 infection.