The emerging role of nuclear factor kappa B in renal cell carcinoma

SEC14L3 knockdown inhibited clear cell renal cell carcinoma proliferation, metastasis and sunitinib resistance through an SEC14L3/RPS3/NFκB positive feedback loop

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) arises from the renal parenchymal epithelium and is the predominant malignant entity of renal cancer, exhibiting increasing incidence and mortality rates over time. SEC14-like 3 (SEC14L3) has emerged as a compelling target for cancer intervention; nevertheless, the precise clinical implications and molecular underpinnings of SEC14L3 in ccRCC remain elusive.

METHODS

By leveraging clinical data and data from the TCGA-ccRCC and GEO datasets, we investigated the association between SEC14L3 expression levels and overall survival rates in ccRCC patients. The biological role and mechanism of SEC14L3 in ccRCC were investigated via in vivo and in vitro experiments. Moreover, siRNA-SEC14L3@PDA@MUC12 nanoparticles (SSPM-NPs) were synthesized and assessed for their therapeutic potential against SEC14L3 through in vivo and in vitro assays.

RESULTS

Our investigation revealed upregulated SEC14L3 expression in ccRCC tissues, and exogenous downregulation of SEC14L3 robustly suppressed the malignant traits of ccRCC cells. Mechanistically, knocking down SEC14L3 facilitated the ubiquitination-mediated degradation of ribosomal protein S3 (RPS3) and augmented IκBα accumulation in ccRCC. This concerted action thwarted the nuclear translocation of P65, thereby abrogating the activation of the nuclear factor kappa B (NFκB) signaling pathway and impeding ccRCC cell proliferation and metastasis. Furthermore, diminished SEC14L3 levels exerted a suppressive effect on NFKB1 expression within the NFκB signaling cascade. NFKB1 functions as a transcriptional regulator capable of binding to the SEC14L3 enhancer and promoter, thereby promoting SEC14L3 expression. Consequently, the inhibition of SEC14L3 expression was further potentiated, thus forming a positive feedback loop. Additionally, we observed that downregulation of SEC14L3 significantly increased the sensitivity of ccRCC cells to sunitinib. The evaluation of SSPM-NPs nanotherapy highlighted its effectiveness in combination with sunitinib for inhibiting ccRCC growth.

CONCLUSION

Our findings not only underscore the promise of SEC14L3 as a therapeutic target but also unveil an SEC14L3/RPS3/NFκB positive feedback loop that curtails ccRCC progression. Modulating SEC14L3 expression to engage this positive feedback loop might herald novel avenues for ccRCC treatment.

APOBEC3C-mediated NF-κB activation enhances clear cell renal cell carcinoma progression

Renowned as the predominant form of kidney cancer, clear cell renal cell carcinoma (ccRCC) exhibits susceptibility to immunotherapies due to its specific expression profile as well as notable immune cell infiltration. Despite this, effectively treating metastatic ccRCC remains a significant challenge, necessitating a more profound comprehension of the underlying molecular mechanisms governing its progression. Here, we unveil that the enhanced expression of the RNA-binding protein DNA dC → dU-editing enzyme APOBEC-3C (APOBEC3C; also known as A3C) in ccRCC tissue and ccRCC-derived cell lines serves as a catalyst for tumor growth by amplifying nuclear factor-kappa B (NF-κB) activity. By employing RNA-sequencing and cell-based assays in ccRCC-derived cell lines, we determined that A3C is a stress-responsive factor and crucial for cell survival. Furthermore, we identified that A3C binds and potentially stabilizes messenger RNAs (mRNAs) encoding positive regulators of the NF-κB pathway. Upon A3C depletion, essential subunits of the NF-κB family are abnormally restrained in the cytoplasm, leading to deregulation of NF-κB target genes. Our study illuminates the pivotal role of A3C in promoting ccRCC tumor development, positioning it as a prospective target for future therapeutic strategies.

The molecular mechanism of NF-κB dysregulation across different subtypes of renal cell carcinoma

BACKGROUND

The nuclear factor kappa B (NF-κB) is a critical pathway that regulates various cellular functions, including immune response, proliferation, growth, and apoptosis. Furthermore, this pathway is tightly regulated to ensure stability in the presence of immunogenic triggers or genotoxic stimuli. The lack of control of the NF-κB pathway can lead to the initiation of different diseases, mainly autoimmune diseases and cancer, including Renal cell carcinoma (RCC). RCC is the most common type of kidney cancer and is characterized by complex genetic composition and elusive molecular mechanisms.

AIM OF REVIEW

The current review summarizes the mechanism of NF-κB dysregulation in different subtypes of RCC and its impact on pathogenesis.

KEY SCIENTIFIC CONCEPT OF REVIEW

This review highlights the prominent role of NF-κB in RCC development and progression by driving the expression of multiple genes and interplaying with different pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. In silico analysis of RCC cohorts and molecular studies have revealed that multiple NF-κB members and target genes are dysregulated. The dysregulation includes receptors such as TLR2, signal-transmitting members including RelA, and target genes, for instance, HIF-1α. The lack of effective regulatory mechanisms results in a constitutively active NF-κB pathway, which promotes cancer growth, migration, and survival. In this review, we comprehensively summarize the role of dysregulated NF-κB-related genes in the most common subtypes of RCC, including clear cell RCC (ccRCC), chromophobe RCC (chRCC), and papillary RCC (PRCC).

Frontier knowledge and future directions of programmed cell death in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common renal malignancies of the urinary system. Patient outcomes are relatively poor due to the lack of early diagnostic markers and resistance to existing treatment options. Programmed cell death, also known as apoptosis, is a highly regulated and orchestrated form of cell death that occurs ubiquitously throughout various physiological processes. It plays a crucial role in maintaining homeostasis and the balance of cellular activities. The combination of immune checkpoint inhibitors plus targeted therapies is the first-line therapy to advanced RCC. Immune checkpoint inhibitors(ICIs) targeted CTLA-4 and PD-1 have been demonstrated to prompt tumor cell death by immunogenic cell death. Literatures on the rationale of VEGFR inhibitors and mTOR inhibitors to suppress RCC also implicate autophagic, apoptosis and ferroptosis. Accordingly, investigations of cell death modes have important implications for the improvement of existing treatment modalities and the proposal of new therapies for RCC. At present, the novel modes of cell death in renal cancer include ferroptosis, immunogenic cell death, apoptosis, pyroptosis, necroptosis, parthanatos, netotic cell death, cuproptosis, lysosomal-dependent cell death, autophagy-dependent cell death and mpt-driven necrosis, all of which belong to programmed cell death. In this review, we briefly describe the classification of cell death, and discuss the interactions and development between ccRCC and these novel forms of cell death, with a focus on ferroptosis, immunogenic cell death, and apoptosis, in an effort to present the theoretical underpinnings and research possibilities for the diagnosis and targeted treatment of ccRCC.

A comprehensive prognostic and immunological analysis of telomere-related lncRNAs in kidney renal clear cell carcinoma

Kidney renal clear cell carcinoma (KIRC) is one of the most prevalent malignant tumors of the urinary system, with a high recurrence and metastasis rate. Telomeres and long non-coding RNAs (lncRNAs) have been documented playing critical roles in cancer progression. However, the prognostic significance of telomere-related lncRNA (TRLs) in KIRC is less well-defined. The Cancer Genome Atlas database was applied to retrieve the expression profiles and corresponding clinical information of KIRC patients. To create the TRLs prognostic signature, univariate Cox regression, least absolute shrinkage and selection operator analyses were performed. The prognostic signature, comprised of nine prognostic TRLs, was developed and demonstrated superior prognostic ability for KIRC patients. Additionally, the risk score acted as an independent prognostic indicator. A nomogram incorporating age, grade, stage, and signature-based risk scores was also developed and exhibited excellent predictive accuracy. Several immune activities were associated with the signature, as determined by gene function analysis. Further analysis revealed differences in the status of immunity and the tumor microenvironment between low- and high-risk groups. Notably, KIRC patients with high-risk scores were more responsive to immunotherapy and chemotherapy. To summarize, our study developed a new prognostic signature consisting of nine telomere-related lncRNA that can precisely predict the prognosis of KIRC patients. The signature was shown to be of substantial value for the tumor microenvironment and tumor mutation burden, thereby contributing to a framework for the individualized treatment of patients.

Epigenetic and transcriptomic characterization reveals progression markers and essential pathways in clear cell renal cell carcinoma

Identifying tumor-cell-specific markers and elucidating their epigenetic regulation and spatial heterogeneity provides mechanistic insights into cancer etiology. Here, we perform snRNA-seq and snATAC-seq in 34 and 28 human clear cell renal cell carcinoma (ccRCC) specimens, respectively, with matched bulk proteogenomics data. By identifying 20 tumor-specific markers through a multi-omics tiered approach, we reveal an association between higher ceruloplasmin (CP) expression and reduced survival. CP knockdown, combined with spatial transcriptomics, suggests a role for CP in regulating hyalinized stroma and tumor-stroma interactions in ccRCC. Intratumoral heterogeneity analysis portrays tumor cell-intrinsic inflammation and epithelial-mesenchymal transition (EMT) as two distinguishing features of tumor subpopulations. Finally, BAP1 mutations are associated with widespread reduction of chromatin accessibility, while PBRM1 mutations generally increase accessibility, with the former affecting five times more accessible peaks than the latter. These integrated analyses reveal the cellular architecture of ccRCC, providing insights into key markers and pathways in ccRCC tumorigenesis.

WY-14643 attenuates lipid deposition via activation of the PPARα/CPT1A axis by targeting Gly335 to inhibit cell proliferation and migration in ccRCC

Background

Histologically, cytoplasmic deposits of lipids and glycogen are common in clear cell renal cell carcinoma (ccRCC). Owing to the significance of lipid deposition in ccRCC, numerous trials targeting lipid metabolism have shown certain therapeutic potential. The agonism of peroxisome proliferator-activated receptor-α (PPARα) via ligands, including WY-14,643, has been considered a promising intervention for cancers.

Methods

First, the effects of WY-14,643 on malignant behaviors were investigated in ccRCC in vitro. After RNA sequencing, the changes in lipid metabolism, especially neutral lipids and glycerol, were further evaluated. Finally, the underlying mechanisms were revealed.

Results

Phenotypically, the proliferation and migration of ccRCC cells treated with WY-14,643 were significantly inhibited in vitro. A theoretical functional mechanism was proposed in ccRCC: WY-14,643 mediates lipid consumption by recognizing carnitine palmitoyltransferase 1 A (CPT1A). Activation of PPARα using WY-14,643 reduces lipid deposition by increasing the CPT1A level, which also suppresses the NF-κB signaling pathway. Spatially, WY-14,643 binds and activates PPARα by targeting Gly335.

Conclusion

Overall, WY-14,643 suppresses the biological behaviors of ccRCC in terms of cell proliferation, migration, and cell cycle arrest. Furthermore, its anticancer properties are mediated by the inhibition of lipid accumulation, at least in part, through the PPARα/CPT1A axis by targeting Gly335, as part of the process, NF-κB signaling is also suppressed. Pharmacological activation of PPARα might offer a new treatment option for ccRCC.

DLK2 Acts as a Potential Prognostic Biomarker for Clear Cell Renal Cell Carcinoma Based on Bioinformatics Analysis

Clear cell renal cell carcinoma (ccRCC) is the most common RCC subtype with a high mortality. It has been reported that delta-like 1 homologue (DLK1) participates in the tumor microenvironmental remodeling of ccRCC, but the relationship between delta-like 2 homologue (DLK2, a DLK1 homologue) and ccRCC is still unclear. Thus, this study aims to investigate the role of DLK2 in the biological function and disease prognosis of ccRCC using bioinformatics analysis. The TNMplot database showed that DLK2 was upregulated in ccRCC tissues. From the UALCAN analysis, the overexpression of DLK2 was associated with advanced stage and high grade in ccRCC. Moreover, the Kaplan-Meier plotter (KM Plotter) database showed that DLK2 upregulation was associated with poor survival outcome in ccRCC. By the LinkedOmics analysis, DLK2 signaling may participated in the modulation of ccRCC extracellular matrix (ECM), cell metabolism, ribosome biogenesis, TGF-β signaling and Notch pathway. Besides, Tumor Immune Estimation Resource (TIMER) analysis showed that the macrophage and CD8⁺ T cell infiltrations were associated with good prognosis in ccRCC patients. Finally, DLK2 overexpression was associated with the reduced macrophage recruitments and the M1–M2 polarization of macrophage in ccRCC tissues. Together, DLK2 may acts as a novel biomarker, even therapeutic target in ccRCC. However, this study lacks experimental validation, and further studies are required to support this viewpoint.

Tackling of Renal Carcinogenesis in Wistar Rats by Silybum marianum Total Extract, Silymarin, and Silibinin via Modulation of Oxidative Stress, Apoptosis, Nrf2, PPARγ, NF-κB, and PI3K/Akt Signaling Pathways

The present work was designed to assess the efficacy of Silybum marianum total extract (STE), silymarin (Sm), and silibinin (Sb) against experimentally induced renal carcinogenesis in male Wistar rats and their roles in regulating oxidative stress, inflammation, apoptosis, and carcinogenesis. The diethylnitrosamine (DEN)/2-acetylaminofluorene (AAF)/carbon tetrachloride (CCl4)-administered rats were orally treated with STE (200 mg/kg b.w.), Sm (150 mg/kg b.w.), and Sb (5 mg/kg b.w.) every other day either from the 1st week or from the 16th week of carcinogen administration to the end of 25th week. The treatments with STE, Sm, and Sb attenuated markers of toxicity in serum, decreased kidney lipid peroxidation (LPO), and significantly reinforced the renal antioxidant armory. The biochemical results were further confirmed by the histopathological alterations. The treatments also led to suppression of proinflammatory mediators such as NF-κβ, p65, Iκβα, and IL-6 in association with inhibition of the PI3K/Akt pathway. Furthermore, they activated the expressions of PPARs, Nrf2, and IL-4 in addition to downregulation of apoptotic proteins p53 and caspase-3 and upregulation of antiapoptotic mediator Bcl-2. The obtained data supply potent proof for the efficacy of STE, Sm, and Sb to counteract renal carcinogenesis via alteration of varied molecular pathways.

TF-RBP-AS Triplet Analysis Reveals the Mechanisms of Aberrant Alternative Splicing Events in Kidney Cancer: Implications for Their Possible Clinical Use as Prognostic and Therapeutic Biomarkers

Aberrant alternative splicing (AS) is increasingly linked to cancer; however, how AS contributes to cancer development still remains largely unknown. AS events (ASEs) are largely regulated by RNA-binding proteins (RBPs) whose ability can be modulated by a variety of genetic and epigenetic mechanisms. In this study, we used a computational framework to investigate the roles of transcription factors (TFs) on regulating RBP-AS interactions. A total of 6519 TF–RBP–AS triplets were identified, including 290 TFs, 175 RBPs, and 16 ASEs from TCGA–KIRC RNA sequencing data. TF function categories were defined according to correlation changes between RBP expression and their targeted ASEs. The results suggested that most TFs affected multiple targets, and six different classes of TF-mediated transcriptional dysregulations were identified. Then, regulatory networks were constructed for TF–RBP–AS triplets. Further pathway-enrichment analysis showed that these TFs and RBPs involved in triplets were enriched in a variety of pathways that were associated with cancer development and progression. Survival analysis showed that some triplets were highly associated with survival rates. These findings demonstrated that the integration of TFs into alternative splicing regulatory networks can help us in understanding the roles of alternative splicing in cancer.

Von Hippel-Lindau (VHL) small-molecule inhibitor binding increases stability and intracellular levels of VHL protein

Von Hippel-Lindau (VHL) disease is characterized by frequent mutation of VHL protein, a tumor suppressor that functions as the substrate recognition subunit of a Cullin2 RING E3 ligase complex (CRL2VHL). CRL2VHL plays important roles in oxygen sensing by targeting hypoxia-inducible factor-alpha (HIF-α) subunits for ubiquitination and degradation. VHL is also commonly hijacked by bifunctional molecules such as proteolysis-targeting chimeras to induce degradation of target molecules. We previously reported the design and characterization of VHL inhibitors VH032 and VH298 that block the VHL:HIF-α interaction, activate the HIF transcription factor, and induce a hypoxic response, which can be beneficial to treat anemia and mitochondrial diseases. How these compounds affect the global cellular proteome remains unknown. Here, we use unbiased quantitative MS to identify the proteomic changes elicited by the VHL inhibitor compared with hypoxia or the broad-spectrum prolyl-hydroxylase domain enzyme inhibitor IOX2. Our results demonstrate that VHL inhibitors selectively activate the HIF response similar to the changes induced in hypoxia and IOX2 treatment. Interestingly, VHL inhibitors were found to specifically upregulate VHL itself. Our analysis revealed that this occurs via protein stabilization of VHL isoforms and not via changes in transcript levels. Increased VHL levels upon VH298 treatment resulted in turn in reduced levels of HIF-1α protein. This work demonstrates the specificity of VHL inhibitors and reveals different antagonistic effects upon their acute versus prolonged treatment in cells. These findings suggest that therapeutic use of VHL inhibitors may not produce overt side effects from HIF stabilization as previously thought.

Upregulation of Rpn10 promotes tumor progression via activation of the NF-κB pathway in clear cell renal cell carcinoma

The ubiquitin-proteasome system (UPS) plays a central role in regulating protein homeostasis in tumor progression. The proteasome subunit Rpn10 is associated with the progression of several tumor types. However, little is known regarding the role of Rpn10 in clear cell renal cell carcinoma (ccRCC). In this study, we found that overexpression of Rpn10 increased ccRCC cell proliferation, migration, and invasion. Silencing Rpn10 expression resulted in decreased cell proli-feration, migration, and invasion in ccRCC cells. Knockdown of Rpn10 inhibits tumor growth and cell proliferation in vivo. Furthermore, we demonstrated that Rpn10 increased cell proliferation, migration, and invasion via regulation of the nuclear factor kappa B (NF-κB) pathway. Rpn10 directly promoted inhibitor of nuclear factor-kappa B alpha (IκBα) degradation through the UPS. Moreover, we observed that upregulation of Rpn10 or downregulation of IκBα in ccRCC was associated with poor prognosis. We found that the combination of these two parameters was a more powerful predictor of poor prognosis than either parameter alone. Collectively, these findings provide evidence that Rpn10 promotes the progression of ccRCC by regulation of the NF-κB pathways and is a prognostic indicator for patients with ccRCC.

Britanin Exhibits Potential Inhibitory Activity on Human Prostate Cancer Cell Lines Through PI3K/Akt/NF-κB Signaling Pathways

Britanin, a natural pseudoguaiacane sesquiterpene lactone, has significant antioxidant and anti-inflammatory activity, but little is known about its tumor inhibitory activity and the underlying mechanism. Here, we demonstrated in vitro and in vivo that britanin inhibited the growth of human prostate cancer cell lines (PC-3, PC-3-LUC, and DU-145). Through in vitro study, the results showed that britanin significantly decreased cell proliferation, migration, and motility. The moderate toxicity of britanin was determined with an acute toxicity study. A luciferase-labeled animal tumor xenograft model and bioluminescence imaging were applied, combining with biological validation for assessing the tumor progression. In vivo results demonstrated that britanin inhibited the growth of PC-3-LUC. The interleukin-2 level in mice was upregulated by britanin, which indicated that britanin induced antitumor immune activation. In addition, britanin downregulated the expression of nuclear factor (NF)-κB p105/p50, pp65, IκBα, pIκBα, phosphoinositide 3-kinase, pPI3k, Akt (protein kinase B, PKB), and pAkt proteins and upregulated expression of Bax. We discovered that britanin inhibits the growth of prostate cancer cells both in vitro and in vivo by regulating PI3K/Akt/NF-κB-related proteins and activating immunity. These findings shed light on the development of britanin as a promising agent for prostate cancer therapy.

Bioinformatic gene analysis for possible biomarkers and therapeutic targets of hypertension-related renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is one of the most prevalent malignant tumors of the urinary system. Hypertension can cause hypertensive nephropathy (HN). Meanwhile, Hypertension is considered to be related to kidney cancer. We analyzed co-expressed genes to find out the relationship between hypertension and RCC and show possible biomarkers and novel therapeutic targets of hypertension-related RCC.

METHODS

We identified the differentially expressed genes (DEGs) of HN and RCC through analyzing Gene Expression Omnibus (GEO) datasets GSE99339, GSE99325, GSE53757 and GSE15641 by means of bioinformatics analysis, respectively. Then we evaluated these genes with protein-protein interaction (PPI) networks, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and CTD database. Subsequently, we verified co-expressed DEGs with Gene Expression Profiling Interactive Analysis (GEPIA) database. Finally, corresponding predicted miRNAs of co-expressed DEGs were identified and verified via mirDIP database and Starbase, respectively.

RESULTS

We identified 9 co-expressed DEGs, including BCAT1, CORO1A, CRIP1, ESRRG, FN1, LYZ, PYCARD, SAP30, and PTRF. CRIP1 and ESRRG and their corresponding predicted miRNAs, especially hsa-miR-221-5p, hsa-miR-205-5p, hsa-miR-152-3p and hsa-miR-137 may be notably related to hypertension-related RCC.

CONCLUSIONS

CRIP1 and ESRRG genes have great potential to become novel biomarkers and therapeutic targets concerning hypertension-related RCC.

Role of the KEAP1-NRF2 Axis in Renal Cell Carcinoma

NRF2 is a transcription factor that coordinates the antioxidant response in many different tissues, ensuring cytoprotection from endogenous and exogenous stress stimuli. In the kidney, its function is essential in appropriate cellular response to oxidative stress, however its aberrant activation supports progression, metastasis, and resistance to therapies in renal cell carcinoma, similarly to what happens in other nonrenal cancers. While at the moment direct inhibitors of NRF2 are not available, understanding the molecular mechanisms that regulate its hyperactivation in specific tumor types is crucial as it may open new therapeutic perspectives. Here, we focus our attention on renal cell carcinoma, describing how NRF2 hyperactivation can contribute to tumor progression and chemoresistance. Furthermore, we highlight the mechanism whereby the many pathways that are generally altered in these tumors converge to dysregulation of the KEAP1-NRF2 axis.

DiSNEP: a Disease-Specific gene Network Enhancement to improve Prioritizing candidate disease genes

Biological network-based strategies are useful in prioritizing genes associated with diseases. Several comprehensive human gene networks such as STRING, GIANT and HumanNet were developed and used in network-assisted algorithms to identify disease-associated genes. However, none of these networks are disease-specific and may not accurately reflect gene interactions for a specific disease. Aiming to improve disease gene prioritization using networks, we propose a Disease-Specific Network Enhancement Prioritization (DiSNEP) framework. DiSNEP first enhances a comprehensive gene network specifically for a disease through a diffusion process on a gene-gene similarity matrix derived from disease omics data. The enhanced disease-specific gene network thus better reflects true gene interactions for the disease and may improve prioritizing disease-associated genes subsequently. In simulations, DiSNEP that uses an enhanced disease-specific network prioritizes more true signal genes than comparison methods using a general gene network or without prioritization. Applications to prioritize cancer-associated gene expression and DNA methylation signal genes for five cancer types from The Cancer Genome Atlas (TCGA) project suggest that more prioritized candidate genes by DiSNEP are cancer-related according to the DisGeNET database than those prioritized by the comparison methods, consistently across all five cancer types considered, and for both gene expression and DNA methylation signal genes.

NF-κB and pSTAT3 synergistically drive G6PD overexpression and facilitate sensitivity to G6PD inhibition in ccRCC

Background

Glucose 6-phosphate dehydrogenase (G6PD) serves key roles in cancer cell metabolic reprogramming, and has been reported to be involved in certain carcinogenesis. Previous results from our laboratory demonstrated that overexpressed G6PD was a potential prognostic biomarker in clear cell renal cell carcinoma (ccRCC), the most common subtype of kidney cancer. G6PD could stimulate ccRCC growth and invasion through facilitating reactive oxygen species (ROS)-phosphorylated signal transducer and activator of transcription 3 (pSTAT3) activation and ROS-MAPK-MMP2 axis pathway, respectively. However, the reasons for ectopic G6PD overexpression and the proliferation repressive effect of G6PD inhibition in ccRCC are still unclear.

Methods

The impact of ROS accumulation on NF-κB signaling pathway and G6PD expression was determined by real-time RT-PCR and Western blot in ccRCC cells following treatment with ROS stimulator or scavenger. The regulatory function of NF-κB signaling pathway in G6PD transcription was analyzed by real-time RT-PCR, Western blot, luciferase and ChIP assay in ccRCC cells following treatment with NF-κB signaling activator/inhibitor or lentivirus infection. ChIP and Co-IP assay was performed to demonstrate protein-DNA and protein-protein interaction of NF-κB and pSTAT3, respectively. MTS assay, human tissue detection and xenograft model were conducted to characterize the association between NF-κB, pSTAT3, G6PD expression level and proliferation functions.

Results

ROS-stimulated NF-κB and pSTAT3 signaling over-activation could activate each other, and exhibit cross-talks in G6PD aberrant transcriptional regulation. The underlying mechanism was that NF-κB signaling pathway facilitated G6PD transcription via direct DNA-protein interaction with p65 instead of p50. p65 and pSTAT3 formed a p65/pSTAT3 complex, occupied the pSTAT3-binding site on G6PD promoter, and contributed to ccRCC proliferation following facilitated G6PD overexpression. G6PD, pSTAT3, and p65 were highly expressed and positively correlated with each other in ccRCC tissues, confirming that NF-κB and pSTAT3 synergistically promote G6PD overexpression. Moreover, G6PD inhibitor exhibited tumor-suppressor activities in ccRCC and attenuated the growth of ccRCC cells both in vitro and in vivo.

Conclusion

ROS-stimulated aberrations of NF-κB and pSTAT3 signaling pathway synergistically drive G6PD transcription through forming a p65/pSTAT3 complex. Moreover, G6PD activity inhibition may be a promising therapeutic strategy for ccRCC treatment.

GYS1 induces glycogen accumulation and promotes tumor progression via the NF-κB pathway in Clear Cell Renal Carcinoma

Metabolism reprogramming is a hallmark of many cancer types. We focused on clear cell renal carcinoma (ccRCC) which is characterized by its clear and glycogen-enriched cytoplasm with unknown reasons. The aim of this study was to identify the clinical significance, biological function, and molecular regulation of glycogen synthase 1 (GYS1) in ccRCC glycogen accumulation and tumor progression. Methods: We determined the clinical relevance of GYS1 and glycogen in ccRCC by immunohistochemistry and periodic acid-schiff staining in fresh tissue and by tissue micro-array. Metabolic profiling with GYS1 depletion was performed by metabolomics analysis. In vitro and xenograft mouse models were used to evaluate the impact of GYS1 on cell proliferation. High-throughput RNA-Seq analyses and co-immunoprecipitation-linked mass spectrometry were used to investigate the downstream targets of GYS1. Flow cytometry and CCK8 assays were performed to determine the effect of GYS1 and sunitinib on cell viability. Results: We observed that GYS1 was significantly overexpressed and glycogen was accumulated in ccRCC tissues. These effects were correlated with unfavorable patient survival. Silencing of GYS1 induced metabolomic perturbation manifested by a carbohydrate metabolism shift. Overexpression of GYS1 promoted tumor growth whereas its silencing suppressed it by activating the canonical NF-κB pathway. The indirect interaction between GYS1 and NF-κB was intermediated by RPS27A, which facilitated the phosphorylation and nuclear import of p65. Moreover, silencing of GYS1 increased the synthetic lethality of ccRCC cells to sunitinib treatment by concomitantly suppressing p65. Conclusions: Our study findings reveal an oncogenic role for GYS1 in cell proliferation and glycogen metabolism in ccRCC. Re-sensitization of ccRCC cells to sunitinib suggests that GYS1 is a useful indicator of unfavorable prognosis as well as a therapeutic target for patients with ccRCC.

HIF-1β Positively Regulates NF-κB Activity via Direct Control of TRAF6

NF-κB signalling is crucial for cellular responses to inflammation but is also associated with the hypoxia response. NF-κB and hypoxia inducible factor (HIF) transcription factors possess an intense molecular crosstalk. Although it is known that HIF-1α modulates NF-κB transcriptional response, very little is understood regarding how HIF-1β contributes to NF-κB signalling. Here, we demonstrate that HIF-1β is required for full NF-κB activation in cells following canonical and non-canonical stimuli. We found that HIF-1β specifically controls TRAF6 expression in human cells but also in Drosophila melanogaster. HIF-1β binds to the TRAF6 gene and controls its expression independently of HIF-1α. Furthermore, exogenous TRAF6 expression is able to rescue all of the cellular phenotypes observed in the absence of HIF-1β. These results indicate that HIF-1β is an important regulator of NF-κB with consequences for homeostasis and human disease.

Differential behavior of NF-κB, IκBα and EGFR during the renal carcinogenic process in an experimental model in vivo

Renal cell carcinoma (RCC) is the most common type of cancer of the adult kidney. It is generally asymptomatic even at advanced stages, so opportune diagnosis is rare, making it almost impossible to study this cancer at its early stages. RCC tumors induced by ferric nitrilotriacetate (FeNTA) in rats histologically correspond to the human clear cell RCC subtype (ccRCC) and the exposure to this carcinogen during either one or two months leads to different early stages of neoplastic development. High levels of nuclear factor kappa B (NF-κB) and epidermal growth factor receptor (EGFR) as well as low levels of NF-κB inhibitor alpha (IκBα) are frequent in human RCC, but their status in FeNTA-induced tumors and their evolution along renal carcinogenesis is unclear. On this basis, in the present study NF-κB, IκBα and EGFR behavior was analyzed at different stages of the experimental renal carcinogenesis model. Similar to patients with RCC, neoplastic tissue showed high levels of p65, one of the predominant subunits of NF-κB in ccRCC and of EGFR (protein and mRNA), as well as a decrease in the levels of NF-κB's main inhibitor, IκBα, resulting in a classic oncogenic combination. Conversely, different responses were observed at early stages of carcinogenesis. After one month of FeNTA-exposure, NF-κB activity and EGFR levels augmented; but unexpectedly, IκBα also did. While after two months, NF-κB activity diminished, but EGFR and IκBα levels remained elevated. In conclusion, FeNTA-induced tumors and RCC human neoplasms are analogues regarding to the classic NF-κB, IκBα and EGFR behavior, and distinctive non-conventional combination of changes is developed at each early stage studied. The results obtained suggest that the dysregulation of the analyzed molecules could be related to different signaling pathways and therefore, to particular effects depending on the phase of the carcinogenic process.

Clinically relevant GSK‑3β inhibitor 9‑ING‑41 is active as a single agent and in combination with other antitumor therapies in human renal cancer

Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase, is involved in a broad range of pathological processes including cancer. GSK-3 has two isoforms, GSK-3α and GSK-3β, and GSK-3β has been recognized as a therapeutic target for the development of new anticancer drugs. The present study aimed to investigate the antitumor effects of 9-ING-41, which is a maleimide-based ATP-competitive small molecule GSK-3β inhibitor active in patients with advanced cancer. In renal cancer cell lines, treatment with 9-ING-41 alone induced cell cycle arrest and apoptosis, and autophagy inhibitors increased the antitumor effects of 9-ING-41 when used in combination. Treatment with 9-ING-41 potentiated the antitumor effects of targeted therapeutics and increased the cytotoxic effects of cytokine-activated immune cells on renal cancer cell lines. These results provided a compelling rationale for the inclusion of patients with renal cancer in studies of 9-ING-41, both as a single agent and in combination with current standard therapies.

Data Mining of Prognostic Microenvironment-Related Genes in Clear Cell Renal Cell Carcinoma: A Study with TCGA Database

Clear cell renal cell carcinoma (ccRCC) is one of the most prevalent kidney malignancies. The tumor microenvironment (TME) is highly related to the oncogenesis, progress, and prognosis of ccRCC. The aim of this study was to infer the level of infiltrating stromal and immune cells and assess the prognostic value of them. The gene expression profile was obtained from TCGA and used for calculating the stromal and immune scores. Based on a cut-off value, patients were divided into low- and high-stromal/immune score groups. Survival analysis was performed to evaluate the prognostic value of stromal and immune scores. Moreover, differentially expressed genes (DEGs) that are highly related to TME were determined and applied for functional enrichment analysis and protein-protein interaction (PPI) network. The Kaplan-Meier plot demonstrated that patients with high-immune scores and stromal scores had poorer clinical outcome. In addition, a total of 89 DEGs were identified and mainly involved in 5 pathways. The top 5 degree genes were extracted from the PPI network; among them, IL10 and XCR1 were highly associated with prognosis of ccRCC. The results of the present study demonstrated that ESTIMATE algorithm-based stromal and immune scores may be a credible indicator of cancer prognosis and IL10 along with XCR1 may be a potential key regulator for the TME of ccRCC.

VHL Expression in Kidney Cancer: Relation to Metastasis Development, Transcription and Growth Factors and Component of Akt/m-TOR Signaling Pathway

Von Hippel-Lindau protein (VHL) is associated with the development and progression of kidney cancer. An increase in VHL expression was found in patients with the disseminated form of the disease compared to the localized cancer, which was combined with a uniform distribution of decreased (<1.0) and increased (>1.0) VHL mRNA levels in renal cancer patients depending on the dissemination of the process. The increase in VHL expression was accompanied an increase in the level of mRNA for NF-κB p65 and kinases PDK1 and Akt. The revealed data indicate the importance of molecular biological parameters in oncogenesis.

Cell death-related molecules and biomarkers for renal cell carcinoma targeted therapy

Renal cell carcinoma (RCC) is not sensitive to conventional radio- and chemotherapies and is at least partially resistant to impairments in cell death-related signaling pathways. The hallmarks of RCC formation include diverse signaling pathways, such as maintenance of proliferation, cell death resistance, angiogenesis induction, immune destruction avoidance, and DNA repair. RCC diagnosed during the early stage has the possibility of cure with surgery. For metastatic RCC (mRCC), molecular targeted therapy, especially antiangiogenic therapy (e.g., tyrosine kinase inhibitors, TKIs, such as sunitinib), is one of the main partially effective therapeutics. Various forms of cell death that may be associated with the resistance to targeted therapy because of the crosstalk between targeted therapy and cell death resistance pathways were originally defined and differentiated into apoptosis, necroptosis, pyroptosis, ferroptosis and autophagic cell death based on cellular morphology. Particularly, as a new form of cell death, T cell-induced cell death by immune checkpoint inhibitors expands the treatment options beyond the current targeted therapy. Here, we provide an overview of cell death-related molecules and biomarkers for the progression, prognosis and treatment of mRCC by targeted therapy, with a focus on apoptosis and T cell-induced cell death, as well as other forms of cell death.

The Adiponectin-AdipoR1 Axis Mediates Tumor Progression and Tyrosine Kinase Inhibitor Resistance in Metastatic Renal Cell Carcinoma

The survival of patients diagnosed with metastatic renal cell carcinoma (RCC) is still limited and the current targeted therapies are only partially effective. Herein, we investigated the clinical value and functions of adiponectin receptors (AdipoR1 and AdipoR2) in metastatic renal cell carcinoma (RCC) patients treated with tyrosine kinase inhibitors (TKIs). A total of 127 mRCC patients treated with first-line TKIs between 2008 and 2017 at a single institution were collected. AdipoR1 and AdipoR2 expression was assessed by immunohistochemistry. AdipoR1 was positively expressed in 87.4% (111/127) of tumors, especially, highly expressed in pulmonary and bone lesions. Patients with low-AdipoR1 expression in primary tumor tissues were more likely to suffer from progressive disease during TKIs treatment (40.0% vs. 11.1%, P = 0 .02), and with decreased progression-free survival (PFS: 19.5 vs. 37.8 mo, P = .001) and overall survival (OS: 62.3 vs 101.1 mo, P = .004) compared to those with high-AdipoR1 expression. Moreover, low-AdipoR1 expression in metastatic tissues was also associated with poor PFS (P = .006) and OS (P = .037). In contrast, AdipoR2 expression was neither associated with sunitinib response nor patient survival. In vitro, we found that adiponectin inhibited migration, invasion and sensitized RCC cells to sunitinib though interacting with AdipoR1, but not AdipoR2. Furthermore, we demonstrated that adiponentin-AdipoR1 axis inhibits tumor cells migration and invasion by blocking the GSK3β/β-Catenin pathway and enhances sunitinib sensitivity via abrogating PI3K/AKT/NF-κB signaling. Our results suggest that adiponentin-AdipoR1 axis may serve as a predictor of TKIs response and could be a potential therapeutic target in the future treatment for metastatic RCC.

UPARANT is an effective antiangiogenic agent in a mouse model of rubeosis iridis

Abstract

Puncture-induced iris neovascularization (rubeosis iridis; RI) in mice is associated with upregulation of extracellular matrix (ECM) degradation and inflammatory factors. The anti-angiogenic and anti-inflammatory efficacy of UPARANT in reducing RI was determined by noninvasive, in vivo iris vascular densitometry, and confirmed in vitro by quantitative vascular-specific immunostaining. Intravitreal administration of UPARANT successfully and rapidly reduced RI to non-induced control levels. Molecular analysis revealed that UPARANT inhibits formyl peptide receptors through a predominantly anti-inflammatory response, accompanied with a significant reduction in ECM degradation and inflammation markers. Similar results were observed with UPARANT administered systemically by subcutaneous injection. These data suggest that the tetrapeptide UPARANT is an effective anti-angiogenic agent for the treatment of RI, both by local and systemic administrations. The effectiveness of UPARANT in reducing RI in a model independent of the canonical vascular endothelial growth factor (VEGF) proposes an alternative for patients that do not respond to anti-VEGF treatments, which could improve treatment in proliferative ocular diseases.

Key messages

UPARANT is effective in the treatment of rubeosis iridis, both by local and systemic administrations.

UPARANT can reduce VEGF-independent neovascularization.

Electronic supplementary material

The online version of this article (10.1007/s00109-019-01794-w) contains supplementary material, which is available to authorized users.

Reduction in H3K4me patterns due to aberrant expression of methyltransferases and demethylases in renal cell carcinoma: prognostic and therapeutic implications

Renal cell carcinoma (RCC) is the leading cause among cancer-related deaths due to urological cancers, which results in response to combination of genetic and epigenetic factors. Histone methylations have been implicated in renal tumorigenesis but their clinical significance and underlying pathology are unexplored. Here, we elucidated the histone 3 lysine 4 (H3K4) methylation patterns in clear cell RCC and its underlying pathology. Lower cellular levels of H3K4 mono-methylation, -dimethylation and -tri-methylation were fraternized with higher TNM staging and Fuhrman grading as well as tumor metastasis. Further, the expression profile of 20 H3K4 modifiers revealed the significant over-expression of histone demethylases compared to methyltransferases, indicating their role in the reduction of H3K4 methylation levels. In view of above facts, the role of LSD2 and KDM5A demethylases in RCC pathogenesis were explored using respective siRNAs. The RCC cells exhibited reduced cell viability after knockdown of LSD2 and KDM5A genes with concomitant induction of apoptosis. In addition, propidium iodide staining demonstrated an arrest of RCC cells at S-phase and sub-G1 phase of the cell cycle. Taken together, these observations provide new pathological insights behind the alterations of H3K4 methylation patterns in ccRCC with their prognostic and therapeutic implications.

Transglutaminase 2: The Maestro of the Oncogenic Mediators in Renal Cell Carcinoma

Transglutaminase 2 (TG2) is a multifunctional crosslinking enzyme that displays transamidation, protein disulfide isomerase, protein kinase, as well as GTPase and ATPase activities. TG2 can also act as an adhesion molecule involved in the syndecan and integrin receptor signaling. In recent years, TG2 was implicated in cancer progression, survival, invasion, migration, and stemness of many cancer types, including renal cell carcinoma (RCC). Von Hippel-Lindau mutations leading to the subsequent activation of Hypoxia Inducible Factor (HIF)-1-mediated signaling pathways, survival signaling via the PI3K/Akt pathway resulting in Epithelial Mesenchymal Transition (EMT) metastasis and angiogenesis are the main factors in RCC progression. A number of studies have shown that TG2 was important in HIF-1- and PI3K-mediated signaling, VHL and p53 stabilization, glycolytic metabolism and migratory phenotype in RCC. This review focuses on the role of TG2 in the regulation of molecular pathways nurturing not only the development and propagation of RCC, but also drug-resistance and metastatic potential.

CXCR1 expression predicts benefit from tyrosine kinase inhibitors therapy in patients with metastatic renal cell carcinoma

PURPOSE

CXCR1 signaling promotes tumor progression in various cancers, and clinical trial has proved efficacy of CXCR1 inhibitor in metastatic breast cancer. Therefore, we investigated the prognostic value of CXCR1 in patients with metastatic renal cell carcinoma (mRCC) receiving tyrosine kinase inhibitors (TKIs) therapy.

MATERIALS AND METHODS

Patients treated with sunitinib or sorafenib were retrospectively enrolled (n = 111). CXCR1 expression was assessed by immunohistochemical staining of tissue microarrays of primary tumor, and its association with prognosis and therapeutic response were evaluated. To explore possible mechanism related to CXCR1 expression, gene set enrichment analysis was performed based on The Cancer Genome Atlas cohort.

RESULTS

High CXCR1 expression was associated with poorer overall survival (P = 0.015) and was an independent prognostic factor for patients with mRCC treated by TKIs (Hazard Ratio = 1.683, 95% Confidence Interval: 1.109-2.553, P = 0.014). CXCR1 expression was also associated with worse therapeutic response of TKIs (P = 0.017). Thirteen pathways, including hypoxia and angiogenesis, were identified to be enriched in CXCR1 positive patients.

CONCLUSIONS

High CXCR1 expression indicates reduced benefit from TKIs therapy in patients with mRCC. The mechanism may be attributed to the enriched pathways of hypoxia and angiogenesis in CXCR1 positive patients. CXCR1 may be a potential therapeutic target for mRCC, but further studies are required.

Cell death-based approaches in treatment of the urinary tract-associated diseases: a fight for survival in the killing fields

Urinary tract-associated diseases comprise a complex set of disorders with a variety of etiologic agents and therapeutic approaches and a huge global burden of disease, estimated at around 1 million deaths per year. These diseases include cancer (mainly prostate, renal, and bladder), urinary tract infections, and urolithiasis. Cell death plays a key role in the pathogenesis and therapy of these conditions. During urinary tract infections, invading bacteria may either promote or prevent host cell death by interfering with cell death pathways. This has been studied in detail for uropathogenic E. coli (UPEC). Inhibition of host cell death may allow intracellular persistence of live bacteria, while promoting host cell death causes tissue damage and releases the microbes. Both crystals and urinary tract obstruction lead to tubular cell death and kidney injury. Among the pathomechanisms, apoptosis, necroptosis, and autophagy represent key processes. With respect to malignant disorders, traditional therapeutic efforts have focused on directly promoting cancer cell death. This may exploit tumor-specific characteristics, such as targeting Vascular Endothelial Growth Factor (VEGF) signaling and mammalian Target of Rapamycin (mTOR) activity in renal cancer and inducing survival factor deprivation by targeting androgen signaling in prostate cancer. An area of intense research is the use of immune checkpoint inhibitors, aiming at unleashing the full potential of immune cells to kill cancer cells. In the future, this may be combined with additional approaches exploiting intrinsic sensitivities to specific modes of cell death such as necroptosis and ferroptosis. Here, we review the contribution of diverse cell death mechanisms to the pathogenesis of urinary tract-associated diseases as well as the potential for novel therapeutic approaches based on an improved molecular understanding of these mechanisms.

Ameliorative potential of sitagliptin and/or resveratrol on experimentally-induced clear cell renal cell carcinoma

The aim of this study was to assess the effect of sitagliptin with or without resveratrol on carcinogen-induced clear cell renal cell carcinoma. Sixty male Wistar rats were divided into 6 equal groups as follows: control; clear cell renal cell carcinoma group; clear cell renal cell carcinoma+sitagliptin group; clear cell renal cell carcinoma+resveratrol group; clear cell renal cell carcinoma+carboxymethyl cellulose group and clear cell renal cell carcinoma+sitagliptin+resveratrol group. Blood urea, serum creatinine, creatinine clearance, urinary N-acetyl beta-d-glucosaminidase (NAG), gamma glutamyl transpeptidase (GGT) and urinary albumin excretion rate (UAER) were determined. Renal tissue antioxidant enzymes, lactate dehydrogenase (LDH), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase-1 (HO-1), transforming growth factor beta-1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and signal transducers and activators of transcription-3 (STAT3) were determined. Parts of the kidneys were subjected to histopathological and immunohistochemical examination for nuclear factor kappa B (p65). Sitagliptin and/or resveratrol induced significant improvement of the renal functions with significant increase in tissue antioxidant defenses and Nrf2/HO-1 content associated with significant decrease in tissue LDH, TGF-β1, TNF-α, IL-6 and STAT3 and alleviated the histopathological and immunohistochemical changes compared to the untreated clear cell renal cell carcinoma group. These effects were significant in sitagliptin/resveratrol combination group compared to the use of each of these drugs alone. In conclusion, sitagliptin/resveratrol combination might represent a beneficial therapeutic modality for amelioration of experimentally-induced clear cell renal cell carcinoma.

Elucidating mechanisms of sunitinib resistance in renal cancer: an integrated pathological-molecular analysis

Upon sunitinib treatment of metastatic renal cell carcinoma patients eventually acquire resistance. Our aim was to investigate microRNAs behind sunitinib resistance.

We developed an in vivo xenograft and an in vitro model and compared morphological, immunhistochemical, transcriptomical and miRNome data changes during sunitinib response and resistance by performing next-generation mRNA and miRNA sequencing. Complex bioinformatics (pathway, BioFunction and network) analysis were performed. Results were validated by in vitro functional assays.

Our morphological, immunhistochemical, transcriptomical and miRNome data all pointed out that during sunitinib resistance tumor cells changed to migratory phenotype. We identified the downregulated miR-1 and miR-663a targeting FRAS1 (Fraser Extracellular Matrix Complex Subunit 1) and MDGA1 (MAM Domain Containing Glycosylphosphatidylinositol Anchor 1) in resistant tumors. We proved firstly miR-1-FRAS1 and miR-663a-MDGA1 interactions. We found that MDGA1 knockdown decreased renal cancer cell migration and proliferation similarly to restoration of levels of miR-1 and miR-663.

Our results support the central role of cell migration as an adaptive mechanism to secure tumor survival behind sunitinib resistance. MDGA1, FRAS1 or the targeting miRNAs can be potential adjuvant therapeutic targets, through inhibition of cancer cell migration, thus eliminating the development of resistance and metastasis.

Dioxonaphthoimidazoliums AB1 and YM155 disrupt phosphorylation of p50 in the NF-κB pathway

The NF-κB pathway is overexpressed in non-small cell lung cancers (NSCLC) and contributes to the poor prognosis and high mortality characterizing this malignancy. Silencing the p50 and p65 NF-κB subunits in the NSCLC H1299 cell line led to profound loss in cell viability and downregulated anti-apoptotic proteins survivin and Mcl1. We also showed that a survivin suppressant, the dioxonaphthoimidazolium YM155, and its structural analog AB1 arrested the growth of H1299 cells at nanomolar concentrations. Both compounds were apoptogenic and suppressed survivin and other anti-apoptotic proteins (Mcl1, Bcl-2, Bcl-xl) in a dose- and/or time-dependent manner. YM155 and AB1 did not affect the expression of key proteins (IκBα, p65, p50) involved in NF-κB signaling. Stable IκBα levels suggest that the NF-κB/IκB complex and proteins upstream of IκBα, were not targeted. Neither did the compounds intercept the nuclear translocation of the p50 and p65 subunits. On the other hand, YM155 and AB1 suppressed the phosphorylation of the p50 subunit at Ser337 which is critical in promoting the binding of NF-κB dimers to DNA. Both compounds duly impeded the binding of NF-κB dimers to DNA and attenuated transcriptional activity of luciferase-transfected HEK293 cells controlled by NF-κB response elements. We propose that the “silencing” the NF-κB pathway effected by these compounds contributed to their potent apoptogenic effects on H1299. Notwithstanding, the mechanism(s) involved in their ability to abolish phosphorylation of p50 remains to be elucidated. Taken together, these results disclose a novel facet of functionalized dioxonaphthoimidazoliums that could account for their potent cell killing property.

Knockdown of NF-κB1 by shRNA Inhibits the Growth of Renal Cell Carcinoma In Vitro and In Vivo

Renal cell carcinoma (RCC) accounts for approximately 2%–3% of human malignancies and is the most aggressive among urologic tumors. Biological heterogeneity, drug resistance, and chemotherapy side effects are the biggest obstacles to the effective treatment of RCC. The NF-κB transcription factor is one of several molecules identified to be responsible for the aggressive phenotype of this tumor. In the past decade, several studies have demonstrated the activation of NF-κB in RCC, and many have implicated NF-κB1 (p50) as an important molecule in tumor progression and metastasis. In the present study, a lentivirus was used to deliver shRNA targeting NF-κB1 into mouse RCC (Renca) cells. It was determined that the knockdown of the NF-κB1 gene led to a reduction in cell proliferation and late apoptosis/necrosis in vitro. Flow cytometry analysis demonstrated G₂/M arrest in the cells. In addition, immunoblotting analysis revealed a significant increase in cyclin B1 and Bax. In vivo experiments showed that Renca-shRNA-NF-κB1 cells have significantly diminished tumorigenicity. Moreover, immunohistochemical analysis revealed an increase in necrotic areas of Renca-shRNA-NF-κB1 tumors. Thus, this study indicates that downregulation of NF-κB1 can suppress RCC tumorigenesis by inducing late apoptosis/necrosis. Therefore, NF-κB1 may be a potential therapeutic target for RCC.

SREBP1-driven lipid desaturation supports clear cell renal cell carcinoma growth through regulation of NF-κB signaling

Clear cell renal cell carcinoma (ccRCC), the most common type of kidney cancers, is an incurable and lethal disease. Although great progresses have been made in understanding the mechanism of ccRCC, metabolic reprogramming in ccRCC remains largely unclear. Here, we showed that lipid desatutation might be a metabolic hallmark of ccRCC. We demonstrated sterol regulatory element-binding protein 1 (SREBP1) is overexpressed in ccRCC cell lines and positively correlated with NF-κB activation. Further, SREBP1 is required for lipid desaturation and cell growth in ccRCC. Mechanistically, we demonstrated that SREBP1-driven lipid desaturation promotes NF-κB activation. Our finding reveals a crucial roles for SREBP1 in lipid desaturation of ccRCC through regulation of NF-κB signaling, which provides not only new insights in regulatory mode of NF-κB signaling but also a novel target for potential metabolic therapies.

Markers of Systemic Inflammatory Response are Prognostic Factors in Patients with Pancreatic Neuroendocrine Tumors (PNETs): A Prospective Analysis

BACKGROUND

The prognosis and behavior of pancreatic neuroendocrine tumors (PNETs) vary and may be divergent even at the same stage or tumor grade. Markers of systemic inflammatory response are readily available and are inexpensive, and have been shown to be prognostic factors in several cancers.

OBJECTIVE

The aim of this study was to evaluate the prognostic utility of markers of systemic inflammatory response in patients with PNETs.

METHODS

A prospective study of 97 patients with PNETs was performed (median follow-up of 15 months, range 12-73 months). Neutrophil-to-lymphocyte ratios (NLRs) and lymphocyte-to-monocyte ratios (LMRs) were calculated at baseline and preoperatively. The primary outcome measures were progression-free survival (PFS) and recurrence-free survival (RFS) after curative resection.

RESULTS

Among all patients, an NLR > 2.3 [hazard ratio (HR) 2.53, 95% confidence interval (CI) 1.05-6.08, p = 0.038] and the presence of distant metastases (HR 2.8, 95% CI 1.26-6.21, p = 0.012) were independent predictors of disease progression. Among patients who did not undergo surgery during the study period, both platelet-to-lymphocyte ratio (PLR) > 160.9 (HR 5.86, 95% CI 1.27-27.08, p = 0.023) and mean platelet volume > 10.75 fL (HR 6.63, 95% CI 1.6-27.48, p = 0.009) were independently associated with worse PFS on multivariable analysis. Among patients who underwent complete resection, an LMR < 3.46 was associated with a worse RFS (HR 9.72, 95% CI 1.19-79.42, p = 0.034).

CONCLUSIONS

PLR > 160.9 and an MPV > 10.75 fL at baseline are independent predictors of disease progression, while an LMR < 3.46 is an independent predictor of tumor recurrence after complete resection in patients with PNETs.

Inhibition of NF-κB Activity Enhances Sensitivity to Anticancer Drugs in Cholangiocarcinoma Cells

Cholangiocarcinoma (CCA) is a dismal cancer. At present, there is no effective chemotherapeutic regimen for CCA. This may be due to the marked resistance of CCA to chemotherapy drugs, for which a mechanism remains unknown. Nuclear factor-κB (NF-κB) is constitutively activated in a variety of cancer cells, including CCA. It has been shown to play roles in growth, metastasis, and chemoresistance of cancer. In the present study, we examined whether NF-κB is involved in the chemoresistance of CCA and whether dehydroxymethylepoxyquinomicin (DHMEQ), an effective NF-κB inhibitor, can overcome the drug resistance of CCA. Two CCA cell lines, KKU-M213 and KKU-M214, were treated with DHMEQ and/or chemotherapeutic drugs. Cell viability, apoptosis, and the expressions of the ATP-binding cassette (ABC) transporters were compared. The combination of chemotherapy drugs, 5-fluorouracil, cisplatin, and doxorubicin, with DHMEQ significantly enhanced the cytotoxicity of all chemotherapeutic drugs compared to DHMEQ or drug alone. Furthermore, the mRNA level of ABCB1, a multidrug-resistant protein, was significantly decreased in the 5-fluorouracil combined with DHMEQ-treated cells. These findings suggest that the inhibition of NF-κB by DHMEQ enhanced the chemoresponsiveness of CCA cells, possibly by reducing the expression of ABC transporter. Inhibition of NF-κB may be a potential chemodrug-sensitizing strategy for chemoresistant cancer such as CCA.

Protection against oxidative stress-induced apoptosis in kidney epithelium by Angelica and Astragalus

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus membranaceus either alone or in combination with Angelica sinensis has been used traditionally for kidney disease in East Asia and China for thousands of years. Previous studies using in vivo animal models have shown the benefits of these medicinal herbs in kidney diseases that involve oxidative stress. However, the mechanisms by which these medicinal herbs protect kidney cells remain largely unknown.

AIM OF THE STUDY

To investigate the mechanisms by which ethanol, methanol and aqueous crude extracts of roots of A. membranaceus and A. sinensis afford protection to human kidney proximal tubular epithelial cells, using an in vitro model of oxidative stress.

MATERIALS AND METHODS

Ethanol, methanol and aqueous extracts of roots of A. membranaceus and A. sinensis were prepared by a three-solvent sequential process. HK2 human kidney proximal tubular epithelial cells were treated with H2O2 alone (0.5mM) or in combination with different concentrations of extracts. Cell mitosis and death (microscopy) and cell viability (MTT assay) were compared. Western immunoblot was used to study expression of apoptosis-related proteins (pro-apoptotic Bax andanti-apoptotic Bcl-XL), and cell survival (NFκB subunits p65 and p50), pro-inflammatory (TNF-α) and protective (TGFβ1) proteins.

RESULTS

H2O2-induced oxidative stress significantly increased apoptosis and reduced cell survival; upregulated pro-apoptotic and down-regulated Bcl-XL; increased NFκB (p65, p50); increased TNFα and decreased TGFβ1. All changes indicated kidney damage and dysfunction. All were modulated by all extracts of both plant species, except for NFκB which was only modulated by extracts of A. membranaceus.

CONCLUSIONS

In conclusion, in a model of oxidative stress that might occur after nephrotoxicity, the plant extracts were protective via anti-apoptotic and anti-inflammatory mechanisms.

Antioxidant, Hepatoprotective Potential and Chemical Profiling of Propolis Ethanolic Extract from Kashmir Himalaya Region Using UHPLC-DAD-QToF-MS

The aim of this study was to examine hepatoprotective effect of ethanolic extract of propolis (KPEt) from Kashmir Himalaya against isoniazid and rifampicin (INH-RIF) induced liver damage in rats. Hepatic cellular injury was initiated by administration of INH-RIF combination (100 mg/kg) intraperitoneal (i.p.) injection for 14 days. We report the protective effects of KPEt against INH-RIF induced liver oxidative stress, inflammation, and enzymatic and nonenzymatic antioxidants. Oral administration of KPEt at both doses (200 and 400 mg/kg body weight) distinctly restricted all modulating oxidative liver injury markers and resulted in the attenuation of INH-RIF arbitrated damage. The free radical scavenging activity of KPEt was evaluated by DPPH, nitric oxide, and superoxide radical scavenging assay. The components present in KPEt identified by ultra high performance liquid chromatography diode array detector time of flight-mass spectroscopy (UHPLC-DAD-QToF-MS) were found to be flavonoids and phenolic acids. The protective efficacy of KPEt is possibly because of free radical scavenging and antioxidant property resulting from the presence of flavonoids and phenolic acids.

Enhanced IMP3 Expression Activates NF-кB Pathway and Promotes Renal Cell Carcinoma Progression

BACKGROUND

Insulin-like growth factor 2 mRNA binding protein 3 (IMP3) is expressed in metastatic and a subset of primary renal cell carcinoma (RCC). However, the role of IMP3 in RCC progression was poorly understood. We aim to uncover the mechanism of IMP3 in regulating clear cell RCC (CCRCC) progression and validate the prognostic significance of IMP3 in localized CCRCC.

METHODS

Caki-1 cells stably overexpressing IMP3 and Achn cells with knockdown of IMP3 were analyzed for cell migration and invasion by Transwell assay. RNA-seq was used to profile gene expression in IMP3-expressing Caki-1 cells. A cohort of 469 localized CCRCC patients were examined for IMP3 expression by immunohistochemistry using tumor tissue array.

RESULTS

IMP3 promoted Caki-1 cell migration and invasion, whereas knockdown of IMP3 by RNAi inhibited Achn cell migration and invasion. Enhanced IMP3 expression activated NF-кB pathway and through which, it functioned in promoting the RCC cell migration. IMP3 expression in localized CCRCC was found to be associated with higher nuclear grade, higher T stage, necrosis and sarcomatoid differentiation (p< 0.001). Enhanced IMP3 expression was correlated with shorter recurrence-free and overall survivals. Multivariable analysis validated IMP3 as an independent prognostic factor for localized CCRCC patients.

CONCLUSION

IMP3 promotes RCC cell migration and invasion by activation of NF-кB pathway. IMP3 is validated to be an independent prognostic marker for localized CCRCC.

Umbelliferone β-d-galactopyranoside inhibits chemically induced renal carcinogenesis via alteration of oxidative stress, hyperproliferation and inflammation: possible role of NF-κB

Umbelliferone (7-hydroxycoumarin) compound possesses strong anti-inflammatory and free radical scavenging activity.

Piperlongumine and its analogs down-regulate expression of c-Met in renal cell carcinoma

The c-Met protein, a transmembrane receptor tyrosine kinase, is the product of a proto-oncogene. Its only known ligand, hepatocyte growth factor (HGF), regulates cell growth, motility, migration, invasion, proliferation, and angiogenesis. The aberrant expression of c-Met is often associated with poor prognosis in multiple cancers, including renal cell carcinoma (RCC). Silencing or inactivation of c-Met leads to decreased viability of cancer cells, thereby making ablation of c-Met signaling an attractive concept for developing novel strategies for the treatment of renal tumors. Naturally-occurring products or substances are the most consistent source of drug development. As such, we investigated the functional impact of piperlongumine (PL), a naturally occurring alkaloid present in the Long pepper (Piper longum) on c-Met expression in RCC cells and demonstrated that PL and its analogs rapidly reduce c-Met protein and RNA levels in RCC cells via ROS-dependent mechanism. PL-mediated c-Met depletion coincided with the inhibition of downstream c-Met signaling; namely Erk/MAPK, STAT3, NF-κB and Akt/mTOR. As such, PL and PL analogs hold promise as potential therapeutic agents for the treatment of metastatic RCC and the prevention of postoperative RCC recurrence.

Involvement of the NF-кB/p50/Bcl-3 complex in response to antiangiogenic therapy in a mouse model of metastatic renal cell carcinoma

Renal cell carcinoma (RCC) represents approximately 2-3% of human malignancies. Nuclear transcription factor кB (NF-кB) is composed of a family of transcription factors that have been associated with the development and progression of RCC. Endostatin (ES) is a fragment of collagen XVIII that possesses antiangiogenic activity. In this study, we evaluated the expression of NF-кB in metastatic tumor cells from animals treated with ES. Balb/c-bearing Renca-EGFP cells were treated with NIH/3T3-LendSN or NIH/3T3-LXSN cells as a control. At the end of the in vivo experiment, plasma Renca-EGFP-sorted cells and tissue lung samples were collected. A real-time PCR array for NF-κB target genes revealed that ES therapy led to down regulation of Bcl-3 (P<0.031), NF-кB1 (P<0.001) and c-Rel (P<0.004) in the ES-treated group. Using an electrophoretic mobility shift assay (EMSA), we observed a reduction in NF-kB binding activity in ES-treated Renca-EGP cells. Furthermore, a supershift assay showed a clear shift of the NF-кB DNA band in samples incubated with a p50 antibody. By immunohistochemistry analysis, ES treatment resulted in a significant reduction in expression of p50. (ES vs. control P<0.05). The immunoprecipitation experiments confirmed the presence of a p50/Bcl-3 complex in nuclear extracts from cells of metastatic lung tissues. Our findings indicate that p50 and Bcl-3 plays a regulatory role in gene transcription in RCC.

Interaction of CCN1 with αvβ3 integrin induces P-glycoprotein and confers vinblastine resistance in renal cell carcinoma cells

Renal cell carcinoma (RCC) ranks among the most chemoresistant tumors, and P-glycoprotein (P-gp) predominates multidrug resistance mechanisms by reducing the accumulation of intracellular chemotherapy drugs such as vinblastine (VBL), which is considered the most effective chemotherapeutic agent for this neoplasia. Unfortunately, the mechanism by which the expression of P-gp is regulated and the ways to inhibit the function of P-gp are poorly understood. Our study was carried out to determine the possible role of CCN1 in P-pg-mediated drug resistance on the basis of the validated function of CCN1, an extracellular matrix protein, in promoting chemoresistance. As expected, CCN1 was overexpressed in VBL-resistant cell lines (ACHN/VBL, A498/VBL, Caki-1/VBL, and Caki-2/VBL) as measured by enzyme-linked immunosorbent assay. We then transfected non-VBL-resistant cell lines with Ad-CCN1 and observed that the IC50 of VBL increased by about 3-5 times. Furthermore, both CCN1 antibody neutralization and αvβ3 integrin antibody blockade decreased the IC50 of VBL, which showed that CCN1 and αvβ3 are associated with resistance to VBL in RCC. Simultaneously, the enhanced expression of CCN1 triggered the intracellular PI3K/Akt pathway by binding αvβ3 integrin, as shown by western blot. P-gp expression was augmented in response to activation of the PI3K/Akt pathway, which could be modified by PI3K inhibitor LY294002 or multidrug resistance siRNA transfection. Therefore, targeted restraint of CCN1 or αvβ3 integrin in combination with the administration of VBL may be beneficial in the treatment of primary and metastatic RCC.