GHITM regulates malignant phenotype and sensitivity to PD-1 blockade of renal cancer cells via Notch signalling.

Growth hormone inducible transmembrane protein (GHITM), one member of Bax inhibitory protein-like family, has been rarely studied, and the clinical importance and biological functions of GHITM in kidney renal clear cell carcinoma (KIRC) still remain unknown. In the present study, we found that GHITM was downregulated in KIRC. Aberrant GHITM downregulation related to clinicopathological feature and unfavourable prognosis of KIRC patients. GHITM overexpression inhibited KIRC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, GHITM overexpression could induce the downregulation of Notch1, which acts as an oncogene in KIRC. Overexpression of Notch1 effectively rescued the inhibitory effect induced by GHITM upregulation. More importantly, GHITM could regulate PD-L1 protein abundance and ectopic overexpression of GHITM enhanced the antitumour efficiency of PD-1 blockade in KIRC, which provided new insights into antitumour therapy. Furthermore, we also showed that YY1 could decrease GHITM level via binding to its promoter. Taken together, our study revealed that GHITM was a promising therapeutic target for KIRC, which could modulate malignant phenotype and sensitivity to PD-1 blockade of renal cancer cells via Notch signalling pathway.

Overcoming the compensatory increase in NRF2 induced by NPL4 inhibition enhances disulfiram/copper-induced oxidative stress and ferroptosis in renal cell carcinoma.

Renal cell carcinoma (RCC) is the most common type of kidney cancer, and it appears to be highly susceptible to ferroptosis. Disulfiram, an alcoholism drug, has been shown to have anticancer properties in various studies, including those on RCC. However, the mechanism of the anticancer effect of disulfiram/copper on RCC remains unclear. In this study, we investigated the impact of disulfiram/copper on RCC treatment using both RCC cells and mouse subcutaneous tumor models. Our findings demonstrate that disulfiram/copper treatment reduced the viability of RCC cells, inhibited their invasion and migration, and disrupted mitochondrial homeostasis, ultimately leading to oxidative stress and ferroptosis. Mechanistically, disulfiram/copper treatment prolonged the half-life of NRF2 and reduced its degradation, but had no effect on transcription, indicating that the disulfiram/copper-induced increase in NRF2 was not related to transcription. Furthermore, we observed that disulfiram/copper treatment reduced the expression of NPL4, a ubiquitin protein-proteasome system involved in NRF2 degradation, while overexpression of NPL4 reversed NRF2 levels and enhanced disulfiram/copper-induced oxidative stress and ferroptosis. These results suggest that overcoming the compensatory increase in NRF2 induced by NPL4 inhibition enhances disulfiram/copper-induced oxidative stress and ferroptosis in RCC. In addition, our in vivo experiments revealed that disulfiram/copper synergized with sorafenib to inhibit the growth of RCC cells and induce ferroptosis. In conclusion, our study sheds light on a possible mechanism for disulfiram/copper treatment in RCC and provides a potential synergistic strategy to overcome sorafenib resistance.

DOT1L Epigenetically Regulates Autophagy and Mitochondria Fusion in Cell Lines of Renal Cancer.

OBJECTIVES: DOT1L, a histone methylase, is overexpression in renal cell cancer. However, the role and detailed molecular mechanism of DOT1L involved in renal cancer development remain unknown. METHODS: The inhibition of DOT1L was used by SGC0946 and short hairpin RNA silencing. Monodansylcadaverine staining and transmission electron microscope were performed to detect autophagy changes as a result of the inhibition of DOT1L. MitoTracker Red assay was used to analyze mitochondrial morphology. The autophagy markers and mitochondria-related proteins were analyzed by Western blot, qPCR, or immunofluorescence. ChIP assay was performed to demonstrate H3K79me2 is involved in the direct regulation of Farnesoid X receptor transcription. RESULTS: DOT1L inhibition increased autophagy activity and promoted mito chondria fusion in cell lines of renal cancer. Inhibition of DOT1L upregulated levels of LC3α/ß, P62, MFN1, and MFN2, which contributed to autophagy activity or mitochondria fusion. DOT1L knockdown showed a similar the above process. DOT1L inhibition or silencing resulted in AMP-activated protein kinase activation and mammalian target of rapamycin inhibition. Mechanistically, the DOT1L inhibitor and its short hairpin RNAs decreased the expression of Farnesoid X receptor in a histone methylase-dependent manner. CONCLUSION: We revealed the essential role of Farnesoid X receptor in regulating DOT1L-induced autophagy and mitochondrial fission through the AMP-activated protein kinase/mammalian target of rapamycin pathway in cell lines of renal cancer, which may provide new insights into the pathogenesis of renal cell cancer.

DOT1L promotes cell proliferation and invasion by epigenetically regulating STAT5B in renal cell carcinoma.

DOT1L, the only histone H3 lysine 79 methyltransferase, has a prominent effect on promoting the progression of various malignancies, yet the functional contribution of DOT1L to renal cell carcinoma (RCC) progression remains unclear. DOT1L is overexpressed in RCC and linked to poor clinical outcomes. Chemical (SGC0946) or genetic suppression of DOT1L attenuates the growth and invasion of renal cancer cells and results in S-phase arrest. STAT5B expression was suppressed after DOT1L knockdown, and STAT5B overexpression rescued the DOT1L silencing-induced decrease in cell proliferation. DOT1L was found to epigenetically promote the transcription of STAT5B via H3K79me2, and CDK6 acted as a downstream effector of STAT5B to mediate cell cycle arrest. Our study confirmed that DOT1L promotes STAT5B expression in a histone methyltransferase-dependent manner. Downregulation of DOT1L inhibited RCC proliferation and invasion. Thus, targeting DOT1L might be a potential therapeutic intervention for RCC.

The role of histone methylation in renal cell cancer: an update.

Renal cell carcinoma accounts for 2-3% of all cancers. It is difficult to diagnose early. Recently, genome-wide studies have identified that histone methylation was one of the functional classes that is most frequently dysregulated in renal cell cancer. Mutation or mis-regulation of histone methylation, methyltransferases, demethylases are associated with gene expression and tumor progression in renal cell cancer. Herein, we summarize histone methylations, demethylases and their alterations and mechanisms in renal cell cancer.

Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma.

BACKGROUND: Nuclear receptor subfamily 1 group H member 4 (NR1H4) have been reported in various cancer types, however, little is known about the clinical values and biological function in clear cell Renal cell carcinoma (ccRCC). METHODS: The expression pattens of NR1H4 in ccRCC were investigated in clinical specimens, cell lines and publicly­available databases. Cell Counting Kit-8 (CCK-8), colony formation, 5-ethynyl-2' -deoxyuridine (EdU), transwell and cell wound healing assays were performed to assess the biological functions of NR1H4 in 786-O ccRCC cells. Gene set enrichment analysis (GSEA), Flow Cytometry, quantitative real-time PCR (qRT-PCR), western blot and immunofluorescence were performed to explore the molecular mechanism of NR1H4 in ccRCC. We explored the early diagnostic value, prognostic value, genetic mutation and DNA methylation of NR1H4 by a comprehensive bioinformatics analysis based on the data published in the following databases: The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Kaplan-Meier Plotter, Gene Expression Profiling Interactive Analysis (GEPIA), UNIVERSITY OF CALIFORNIA SANTA CRUZ Xena (UCSC Xena), cBio Cancer Genomics Portal, MethSurv, SurvivalMeth and The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN). Its correlation with tumor-infiltrating immune cells in ccRCC was analyzed by Tumor Immune Estimation Resource 2.0 (TIMER2.0) and Tumor Immune System Interactions Database (TISIDB). RESULTS: In this study, NR1H4 was found to be highly expressed in ccRCC tissues and ccRCC cell lines. Knockdown of NR1H4 significantly suppressed cancer cell proliferation, migration and invasion. Mechanistically, tumor-associated signaling pathways were enriched in the NR1H4 overexpression group and si-NR1H4 could induce the downregulation of Cyclin E2 (CCNE2). By bioinformatics analysis, NR1H4 was identified as highly expressed in stage I ccRCC with a high diagnostic accuracy (area under the receiver operating characteristic curve > 0.8). Genetic alteration and DNA methylation of NR1H4 were significantly associated with prognosis in ccRCC patients. Moreover, NR1H4 expression associated with immune cell infiltration levels in ccRCC, which provides a new idea for immunotherapy. CONCLUSIONS: Our study indicated that NR1H4 might be a potential tumor biomarker and therapeutic target for ccRCC which could promote cancer cell proliferation, migration and invasion via regulating CCNE2.

A prognosis model for clear cell renal cell carcinoma based on four necroptosis-related genes.

Necroptosis is a type of caspase-independent cell death, and it plays a critical role in regulating the development of cancer. To date, little is known about the role of necroptosis-related genes (NRGs) in clear cell renal cell carcinoma (ccRCC). In this study, we downloaded data regarding the expression of NRGs and overall survival (OS) from The Cancer Genome Atlas (TCGA) database and constructed a risk model to determine the prognostic features of necroptosis using COX regression analysis. Patients with ccRCC were divided into low-risk and high-risk groups based on their risk scores. Thereafter, Kaplan-Meier curves were used to evaluate OS, and receiver operating characteristic (ROC) curves were used to determine the accuracy of prediction. Stratified analyses were performed according to different clinical variables. Furthermore, we assessed the correlation between clinical variables and risk scores; the NRGs with differential expression were mainly enriched in positive regulation of intracellular transport and platinum resistance pathways. We constructed prognostic signatures for OS based on four NRGs and showed that the survival time was significantly longer in the low-risk groups than in the high-risk groups (p < 0.001). The area of the ROC curve for OS was 0.717, indicating excellent predictive accuracy of the established model. Therefore, a predictive model based on NRGs was constructed, which can predict the prognosis of patients and provides insights into the biological mechanisms underlying necroptosis in patients with ccRCC.

Photo-Detachable Self-Cleaning Surfaces Inspired by Gecko Toepads.

Strong, reversible, and self-cleaning adhesion in the toe pads of geckos allow the lizards to climb on a variety of vertical and inverted surfaces, regardless of the surface conditions, whether hydrophobic or hydrophilic, smooth or tough, wet or dry, clean or dirty. Development of synthetic gecko-inspired surfaces has drawn a great attention over the past two decades. Despite many external-stimuli responsive mechanisms (i.e., thermal, electrical, magnetic) have been successfully demonstrated, smart adhesives controlled by light signals still substantially lag behind. Here, in this report, we integrate tetramethylpiperidinyloxyl (TEMPO)-doped polydopamine (PDA), namely, TDPDA, with PDMS micropillars using a template-assisted casting method, to achieve both improved adhesion and self-cleaning performances. To the best of our knowledge, this is the first report on PDA being used as a doping nanoparticle in bioinspired adhesive surfaces to achieve highly efficient self-cleaning controllable by light signals. Notably, the adhesion of the 5% TDPDA-PDMS sample is ∼688.75% higher than that of the pure PDMS at the individual pillar level, which helps to explain the highly efficient self-cleaning mechanism. The sample surfaces (named TDPDA-PDMS) can efficiently absorb 808 nm wavelength of light and heat up from 25 °C to 80.9 °C in 3 min with NIR irradiation. The temperature rise causes significant reduction of adhesion, which results in outstanding self-cleaning rate of up to 55.8% within five steps. The exploration of the photoenabled switching mechanism with outstanding sensitivity may bring the biomimetic smart surfaces into a new dimension, rendering varied applications, e.g., in miniaturized climbing robot, artificial intelligence programmable manipulation/assembly/filtration, active self-cleaning solar panels, including high output sensors and devices in many engineering and biomedical frontiers.

Recombinant Ricin Toxin Binding Subunit B (RTB) Stimulates Production of TNF-α by Mouse Macrophages Through Activation of TLR4 Signaling Pathway.

Ricin toxin binding subunit B (RTB) is a galactose-binding lectin protein derived from the beans of the castor oil plant (Ricinus communis). Our previous studies have reported a direct immunomodulatory effect of recombinant RTB, which stimulates RAW264.7 cells to produce cytokines including TNF-α. However, the role of RTB in innate immune response and its specific mechanism have not been reported in detail. In this work, the results showed that RTB treatment of macrophages significantly increased TLR4 protein levels. RTB also activated TLR4 downstream events, including MyD88, IRAK, and TRAF6, resulting in macrophage activation and TNF-α production. This process is reflected in the increase of IκB phosphorylation. TLR4 knockdown macrophages treated with RTB exhibited greatly reduced IκB phosphorylation and TNF-α secretion. Moreover, treatment with MyD88 inhibitor also suppressed TNF-α production. The docking of RT and TLR4 was simulated by computer, and the contact residues were concentrated on RTB. Our results suggest that recombinant RTB can activate mouse macrophages to secrete TNF-α through activation of NF-κB via the TLR4 signaling pathways.