HSF4/COIL complex-dependent R-loop mediates ultraviolet-induced inflammatory skin injury.

Intense ultraviolet (UV) exposure can cause phototoxic reactions, such as skin inflammation, resulting in injury. UV is a direct cause of DNA damage, but the mechanisms underlying transcriptional regulation within cells after DNA damage are unclear. The bioinformatics analysis of transcriptome sequencing data from UV-irradiated and non-UV-irradiated skin showed that transcription-related proteins, such as HSF4 and COIL, mediate cellular response to UV irradiation. HSF4 and COIL can form a complex under UV irradiation, and the preference for binding target genes changed because of the presence of a large number of R-loops in cells under UV irradiation and the ability of COIL to recognize R-loops. The regulation of target genes was altered by the HSF4-COIL complex, and the expression of inflammation and ageing-related genes, such as Atg7, Tfpi, and Lims1, was enhanced. A drug screen was performed for the recognition sites of COIL and R-loop. N6-(2-hydroxyethyl)-adenosine can competitively bind COIL and inhibit the binding of COIL to the R-loop. Thus, the activation of downstream inflammation-related genes and inflammatory skin injury was inhibited.

Salidroside can target both P4HB-mediated inflammation and melanogenesis of the skin.

Rationale: Many external factors can induce the melanogenesis and inflammation of the skin. Salidroside (SAL) is the main active ingredient of Rhodiola, which is a perennial grass plant of the Family Crassulaceae. This study evaluated the effect and molecular mechanism of SAL on skin inflammation and melanin production. It then explored the molecular mechanism of melanin production under ultraviolet (UV) and inflammatory stimulation. Methods: VISIA skin analysis imaging system and DermaLab instruments were used to detect the melanin reduction and skin brightness improvement rate of the volunteers. UV-treated Kunming mice were used to detect the effect of SAL on skin inflammation and melanin production. Molecular docking and Biacore were used to verify the target of SAL. Immunofluorescence, luciferase reporter assay, CO-IP, pull-down, Western blot, proximity ligation assay (PLA), and qPCR were used to investigate the molecular mechanism by which SAL regulates skin inflammation and melanin production. Results: SAL can inhibit the inflammation and melanin production of the volunteers. SAL also exerted a protective effect on the UV-treated Kunming mice. SAL can inhibit the tyrosinase (TYR) activity and TYR mRNA expression in A375 cells. SAL can also regulate the ubiquitination degradation of interferon regulatory factor 1 (IRF1) by targeting prolyl 4-hydroxylase beta polypeptide (P4HB) to mediate inflammation and melanin production. This study also revealed that IRF1 and upstream stimulatory factor 1 (USF1) can form a transcription complex to regulate TYR mRNA expression. IRF1 also mediated inflammatory reaction and TYR expression under UV- and lipopolysaccharide-induced conditions. Moreover, SAL derivative SAL-plus (1-(3,5-dihydroxyphenyl) ethyl-ß-d-glucoside) showed better effect on inflammation and melanin production than SAL. Conclusion: SAL can inhibit the inflammation and melanogenesis of the skin by targeting P4HB and regulating the formation of the IRF1/USF1 transcription complex. In addition, SAL-plus may be a new melanin production and inflammatory inhibitor.

Targeted Drug-Loaded Chemical Probe Staining Assay to Predict Therapy Response and Function as an Independent Pathological Marker.

Multi-targeted kinase inhibitors, such as sorafenib, have been used in various malignancies, but their efficacy in clinical applications varies among individuals and lacks pretherapeutic prediction measures. We applied the concept of "click chemistry" to pathological staining and established a drug-loaded probe staining assay. We stained the cells and different types of pathological sections and demonstrated that the assay was reliable. We further verified in cells, cell-derived xenograft model, and clinical level that the staining intensity of the probe could reflect drug sensitivity. The stained samples from 300 patients who suffered from hepatocellular carcinoma and used the sorafenib probe also indicated that staining intensity was closely related to clinical information and could be used as an independent marker without undergoing sorafenib therapy for prognosis. This assay provided new ideas for multi-target drug clinical trials, pre-medication prediction, and pathological research.

Hsp90ß promotes aggressive vasculogenic mimicry via epithelial-mesenchymal transition in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a typical hypervascular solid tumor. Vasculogenic mimicry (VM) formed by aggressive tumor cells to mimic vasculogenic networks plays an important role in the tumor malignancy of HCC. Hsp90ß promotes endothelial cell-dependent angiogenesis in HCC. However, the relationship between Hsp90ß and VM formation is unclear. In this study, we found that Hsp90ß is positively correlated with VM and EMT marker proteins in HCC tissues and promotes tube formation, cell migration, and invasion in vitro. Hsp90ß interacts with Twist1 and promotes its deubiquitination and stabilization to nuclear translocation and enhances the VE-cadherin promoter activity. Results of in vitro analysis indicate that Hsp90ß enhances the tumor VM in tumor-burdened mice, and the Hsp90 inhibitor NVP-BEP800 suppresses VM formation by releasing Hsp90ß and Twist1 interaction. This study provides a potential antitumor therapy for inhibiting VM by targeting Hsp90ß in HCC.

Twist1 Regulates Vimentin through Cul2 Circular RNA to Promote EMT in Hepatocellular Carcinoma.

Twist is a critical epithelial-mesenchymal transition (EMT)-inducing transcription factor that increases expression of vimentin. How Twist1 regulates this expression remains unclear. Here, we report that Twist1 regulates Cullin2 (Cul2) circular RNA to increase expression of vimentin in EMT. Twist1 bound the Cul2 promoter to activate its transcription and to selectively promote expression of Cul2 circular RNA (circ-10720), but not mRNA. circ-10720 positively correlated with Twist1, tumor malignance, and poor prognosis in hepatocellular carcinoma (HCC). Twist1 promoted vimentin expression by increasing levels of circ-10720, which can absorb miRNAs that target vimentin. circ-10720 knockdown counteracted the tumor-promoting activity of Twist1 in vitro and in patient-derived xenograft and diethylnitrosamine-induced TetOn-Twist1 transgenic mouse HCC models. These data unveil a mechanism by which Twist1 regulates vimentin during EMT. They also provide potential therapeutic targets for HCC treatment and provide new insight for circular RNA (circRNA)-based diagnostic and therapeutic strategies.Significance: A circRNA-based mechanism drives Twist1-mediated regulation of vimentin during EMT and provides potential therapeutic targets for treatment of HCC.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/15/4150/F1.large.jpg Cancer Res; 78(15); 4150-62. ©2018 AACR.

Derepression of co-silenced tumor suppressor genes by nanoparticle-loaded circular ssDNA reduces tumor malignancy.

The co-silencing of multiple tumor suppressor genes can lead to escalated malignancy in cancer cells. Given the limited efficacy of anticancer therapies targeting single tumor suppressor genes, we developed small circular single-stranded DNA (CSSD) that can up-regulate the expression of co-silenced tumor suppressor genes by sequestering microRNAs (miRNAs) that negatively regulate these genes. We found that cancer patients with low tumor expression of the tumor suppressor genes KLF17, CDH1, and LASS2 had shortened survival times. The up-regulation of these genes upon transfection of artificial CSSD-9 inhibited tumor proliferation and metastasis and promoted apoptosis in vitro as well as in ex vivo and patient-derived xenograft models. In addition, CSSD is more stable and effective than current miRNA inhibitors, and transfecting CSSDs via nanoparticles substantially improved delivery efficiency. The use of a single CSSD can promote the inhibition of multiple tumor suppressor genes. This study provides evidence for the possibility of using CSSDs as therapeutic miRNA inhibitors to target the co-silencing of multiple tumor suppressor genes.