NF-κB inhibition by bortezomib permits IFN-γ-activated RIP1 kinase-dependent necrosis in renal cell carcinoma

Clinical features, treatment, and outcomes of patients with carfilzomib induced thrombotic microangiopathy

BACKGROUND

Thrombotic microangiopathy (TMA) is associated with carfilzomib, and knowledge of carfilzomib-induced TMA is based mainly on case reports. This study investigated the clinical characteristics of patients with carfilzomib-induced TMA and provided a reference for the rational use of carfilzomib.

METHODS

Reports of carfilzomib-induced TMA were collected for retrospective analysis by searching the Chinese and English databases from inception to January 31, 2024.

RESULTS

Sixty-six patients were included, with a median age of 63 years (range 39, 85). The median time to onset of TMA was 42 days (range 1, 1825) from initial administration, and the median number of cycles was 3 cycles (range 1, 15). Hemolytic anemia was recorded in 64 patients, with a median of 8.3 g/dL (range 4.6, 13). Sixty-three patients had thrombocytopenia with a median of 18 × 109/L (range 1, 139). The median value of increased LDH was 1192 IU/L (range 141, 5378). ADAMTS13 activity was normal in 41 (62.1 %) of the 42 patients. Mutations were found in 9 (13.6 %) of the 15 patients. Fifty-seven patients achieved a clinical response after discontinuing carfilzomib and receiving therapeutic plasma exchange (53.0 %), eculizumab (24.2 %), or hemodialysis (39.4 %).

CONCLUSION

Carfilzomib-induced TMA is an important adverse event that should be considered in patients receiving carfilzomib for multiple myeloma with anemia, thrombocytopenia, and acute kidney injury. Withdrawal of carfilzomib and treatment with eculizumab have proven successful in some patients.

Bortezomib suppresses acute myelogenous leukaemia stem-like KG-1a cells via NF-κB inhibition and the induction of oxidative stress

Acute myelogenous leukaemia (AML) originates and is maintained by leukaemic stem cells (LSCs) that are inherently resistant to antiproliferative therapies, indicating that a critical strategy for overcoming chemoresistance in AML therapy is to eradicate LSCs. In this work, we investigated the anti-AML activity of bortezomib (BTZ), emphasizing its anti-LSC potential, using KG-1a cells, an AML cell line with stem-like properties. BTZ presented potent cytotoxicity to both solid and haematological malignancy cells and reduced the stem-like features of KG-1a cells, as observed by the reduction in CD34- and CD123-positive cells. A reduction in NF-κB p65 nuclear staining was observed in BTZ-treated KG-1a cells, in addition to upregulation of the NF-κB inhibitor gene NFΚBIB. BTZ-induced DNA fragmentation, nuclear condensation, cell shrinkage and loss of transmembrane mitochondrial potential along with an increase in active caspase-3 and cleaved PARP-(Asp 214) level in KG-1a cells. Furthermore, BTZ-induced cell death was partially prevented by pretreatment with the pancaspase inhibitor Z-VAD-(OMe)-FMK, indicating that BTZ induces caspase-mediated apoptosis. BTZ also increased mitochondrial superoxide levels in KG-1a cells, and BTZ-induced apoptosis was partially prevented by pretreatment with the antioxidant N-acetylcysteine, indicating that BTZ induces oxidative stress-mediated apoptosis in KG-1a cells. At a dosage of 0.1 mg/kg every other day for 2 weeks, BTZ significantly reduced the percentage of hCD45-positive cells in the bone marrow and peripheral blood of NSG mice engrafted with KG-1a cells with tolerable toxicity. Taken together, these data indicate that the anti-LSC potential of BTZ appears to be an important strategy for AML treatment.

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.

No Time to Die: How Kidney Cancer Evades Cell Death

The understanding of the pathogenesis of renal cell carcinoma led to the development of targeted therapies, which dramatically changed the overall survival rate. Nonetheless, despite innovative lines of therapy accessible to patients, the prognosis remains severe in most cases. Kidney cancer rarely shows mutations in the genes coding for proteins involved in programmed cell death, including p53. In this paper, we show that the molecular machinery responsible for different forms of cell death, such as apoptosis, ferroptosis, pyroptosis, and necroptosis, which are somehow impaired in kidney cancer to allow cancer cell growth and development, was reactivated by targeted pharmacological intervention. The aim of the present review was to summarize the modality of programmed cell death in the pathogenesis of renal cell carcinoma, showing in vitro and in vivo evidence of their potential role in controlling kidney cancer growth, and highlighting their possible therapeutic value.

Causal integration of multi-omics data with prior knowledge to generate mechanistic hypotheses

Multi-omics datasets can provide molecular insights beyond the sum of individual omics. Various tools have been recently developed to integrate such datasets, but there are limited strategies to systematically extract mechanistic hypotheses from them. Here, we present COSMOS (Causal Oriented Search of Multi-Omics Space), a method that integrates phosphoproteomics, transcriptomics, and metabolomics datasets. COSMOS combines extensive prior knowledge of signaling, metabolic, and gene regulatory networks with computational methods to estimate activities of transcription factors and kinases as well as network-level causal reasoning. COSMOS provides mechanistic hypotheses for experimental observations across multi-omics datasets. We applied COSMOS to a dataset comprising transcriptomics, phosphoproteomics, and metabolomics data from healthy and cancerous tissue from eleven clear cell renal cell carcinoma (ccRCC) patients. COSMOS was able to capture relevant crosstalks within and between multiple omics layers, such as known ccRCC drug targets. We expect that our freely available method will be broadly useful to extract mechanistic insights from multi-omics studies.

Management of nephrotoxicity of chemotherapy and targeted agents: 2020

Nephrotoxic effects of certain chemotherapeutic agents such as cisplatin and ifosfamide has been well documented and these effects are carefully managed by oncologists during their usage. The introduction of targeted agents has added a new challenge to cancer management as their nephrotoxic effects and associated management is in the process of being adopted by oncologists. This work is a compilation of side effects on the renal system due to various chemotherapeutic, immunotherapeutic and targeted agents followed by their recommended management.

Complex roles of necroptosis in cancer

Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein (RIP) kinases RIPK1 and RIPK3, as well as the RIPK3 substrate mixed lineage kinase domain-like protein (MLKL). Because of membrane rupture, necroptotic cells release damage-associated molecular patterns (DAMPs) that evoke immune responses. Necroptosis is emerging as an important cellular response in the modulation of cancer initiation, progression, and metastasis. Necroptosis of cancer cells is considered to be an immunogenic cell death capable of activating anti-tumor immunity. Necroptosis also participates in the promotion of myeloid cell-induced adaptive immune suppression and thus contributes to oncogenesis. In addition, necroptosis of endothelial cells and tumor cells is conducive to tumor metastasis. In this review, we summarize the current knowledge of the complex role of necroptosis in cancer and discuss the potential of targeting necroptosis components for cancer therapies.

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.

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.

An Overview of Pathways of Regulated Necrosis in Acute Kidney Injury

Necrosis is the predominant form of regulated cell death in acute kidney injury (AKI) and represents results in the formation of casts that appear in the urine sedimentation, referred to as muddy brown casts, which are part of the diagnosis of AKI. Pathologists referred to this typical feature as acute tubular necrosis. We are only beginning to understand the dynamics and the molecular pathways that underlie such typical necrotic morphology. In this review, we provide an overview of candidate pathways and summarize the emerging evidence for the relative contribution of these pathways of regulated necrosis, such as necroptosis, ferroptosis, mitochondrial permeability transition-mediated regulated necrosis, parthanatos, and pyroptosis. Inhibitors of each of these pathways are available, and clinical trials may be started after the detection of the most promising drug targets, which will be discussed here. With the global burden of AKI in mind, inhibitiors of regulated necrosis represent promising means to prevent this disease.

Proteasome inhibitor bortezomib enhances the effect of standard chemotherapy in small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive cancer showing a very poor prognosis because of metastasis formation at an early stage and acquisition of chemoresistance. One key driver of chemoresistance is the transcription factor Forkhead box protein M1 (FOXM1) that regulates cell cycle proliferation, maintenance of genomic stability, DNA damage response, and cell differentiation in numerous tumor entities. In this study we investigated the role of FOXM1 in SCLC progression and analyzed the effect of FOXM1 inhibition using two proteasome inhibitors, bortezomib and siomycin A. FOXM1 was strongly expressed in patient-derived SCLC samples (n=123) and its nuclear localization was associated with the proliferation marker Ki-67. Both proteasome inhibitors successfully inhibited FOXM1 expression leading to a significantly reduced proliferation and a decreased mitotic rate along with cell cycle arrest and apoptosis induction. These effects were further enhanced by addition of bortezomib to standard chemotherapy. Treatment of mice bearing chemoresistant SCLC xenografts with bortezomib reduced the mean bioluminescence signal of tumors by 54%. Similarly, treatment with cisplatin as a standard chemotherapy reduced the mean bioluminescence signal of tumors by 58%. However, in combination with standard chemotherapy bortezomib further reduced the mean bioluminescence signal by 93% (p=0.0258). In conclusion, we demonstrate the effect of bortezomib in inhibiting FOXM1 expression and thus in sensitizing resistant SCLC cells to standard chemotherapy. Thus, addition of bortezomib to standard chemotherapy might potently improve SCLC therapy, particularly in an extensive cancer stage.

An exploratory clinical trial of bortezomib in patients with lower risk myelodysplastic syndromes

Myelodysplastic syndromes (MDSs) are characterized by ineffective hematopoiesis and an increased risk of transformation. Few effective therapies are available for lower risk MDS patients, especially after the failure of hypomethylating agents. MDS progenitor cells are dependent on the nuclear factor-κB (NF-κB) for survival, which makes it an attractive therapeutic target. As a proteosomal inhibitor, bortezomib is thought to have inhibitory activity against NF-κB. We designed a proof-of-principle study of subcutaneous (SC) bortezomib in lower risk MDS patients with evidence of NF-κB activation in their bone marrow. Fifteen patients were treated, their median age was 71 (range 56-87), 33% were low and 67% int-1 by IPSS, median number of prior therapies was 2, all patients were transfusion dependent. Baseline median pp65 percentage was 31% and 11 patients had evidence of ring sideroblasts (RS). SC bortezomib was safe, well tolerated with no excess toxicity. Three patients out of the 15 (20%) had evidence of response with hematologic improvement (HI-E). Bortezomib caused a decrease in pp65 levels in 7 out of 13 evaluable patients (54%, P = .025). Of interest, unexpectedly, we observed a significant decrease in RS in 7 out of 10 (70%) evaluable patients during treatment. In conclusion, this study suggests that NF-κB activation, measured by pp65 levels, may be a useful biomarker in MDS. Bortezomib is safe in this patient population but has modest clinical activity. The role of the proteasome in the genesis of RS needs further study.

Renal Toxicities of Novel Agents Used for Treatment of Multiple Myeloma

Survival for patients with multiple myeloma has significantly improved in the last decade in large part due to the development of proteasome inhibitors and immunomodulatory drugs. These next generation agents with novel mechanisms of action as well as targeted therapies are being used both in the preclinical and clinical settings for patients with myeloma. These agents include monoclonal antibodies, deacetylase inhibitors, kinase inhibitors, agents affecting various signaling pathways, immune check point inhibitors, and other targeted therapies. In some cases, off target effects of these therapies can lead to unanticipated effects on the kidney that can range from electrolyte disorders to AKI. In this review, we discuss the nephrotoxicities of novel agents currently in practice as well as in development for the treatment of myeloma.

Bortezomib Inhibits Giant Cell Tumor of Bone through Induction of Cell Apoptosis and Inhibition of Osteoclast Recruitment, Giant Cell Formation, and Bone Resorption

Giant cell tumor of bone (GCTB) is a rare and highly osteolytic bone tumor that usually leads to an extensive bone lesion. The purpose of this study was to discover novel therapeutic targets and identify potential agents for treating GCTB. After screening the serum cytokine profiles in 52 GCTB patients and 10 normal individuals using the ELISA assay, we found that NF-κB signaling-related cytokines, including TNFα, MCP-1, IL1α, and IL17A, were significantly increased in GCTB patients. The results were confirmed by IHC that the expression and activity of p65 were significantly increased in GCTB patients. Moreover, all of the NF-κB inhibitors tested suppressed GCTB cell growth, and bortezomib (Velcade), a well-known proteasome inhibitor, was the most potent inhibitor in blocking GCTB cells growth. Our results showed that bortezomib not only induced GCTB neoplastic stromal cell (NSC) apoptosis, but also suppressed GCTB NSC-induced giant cell differentiation, formation, and resorption. Moreover, bortezomib specifically suppressed GCTB NSC-induced preosteoclast recruitment. Furthermore, bortezomib ameliorated GCTB cell-induced bone destruction in vivo As a result, bortezomib suppressed NF-κB-regulated gene expression in GCTB NSC apoptosis, monocyte migration, angiogenesis, and osteoclastogenesis. Particularly, the inhibitory effects of bortezomib were much better than zoledronic acid, a drug currently used in treating GCTB, in our in vitro experimental paradigms. Together, our results demonstrated that NF-κB signaling pathway is highly activated in GCTB, and bortezomib could suppress GCTB and osteolysis in vivo and in vitro, indicating that bortezomib is a potential agent in the treatment of GCTB. Mol Cancer Ther; 15(5); 854-65. ©2016 AACR.

Thrombotic microangiopathy associated with proteasome inhibitors

The ubiquitin proteasome pathway plays a key role in cell cycle, function and survival. Bortezomib (BTZ) and Carfilzomib (CFZ) are the first two inhibitors of the proteasome pathway, indicated in treatment of patients with multiple myeloma. In the past few years, there have been few case reports that have highlighted the association between proteasome inhibitors (BTZ and CFZ) with acute kidney injury (AKI). In most of these case reports and initial trials, the underlying mechanism of AKI has been unclear. In this article, we discuss the association and pathogenesis of proteasome inhibitors-associated AKI. We also report the first case of CFZ-associated AKI with kidney biopsy evidence of thrombotic microangiopathy and the presence of microangiopathic hemolytic anemia.

Manipulation of apoptosis and necroptosis signaling by herpesviruses

Like apoptosis, necroptosis is an innate immune mechanism that eliminates pathogen-infected cells. Receptor-interacting protein kinase (RIP)3 (also called RIPK3) mediates necrotic death by phosphorylating an executioner protein, MLKL, leading to plasma membrane leakage. The pathway is triggered against viruses that block caspase 8. In murine CMV, the viral inhibitor of caspase 8 activation prevents extrinsic apoptosis but also has the potential to unleash necroptosis. This virus encodes the viral inhibitor of RIP activation to prevent RIP homotypic interaction motif (RHIM)-dependent signal transduction and necroptosis. Recent investigations reveal a similar mechanism at play in the human alpha-herpesviruses, herpes simplex virus (HSV)1 and HSV2, where RHIM competitor function and caspase 8 suppression are carried out by the virus-encoded large subunit of ribonucleotide reductase (R1). In human cells, R1 inhibition of caspase 8 prevents TNF-induced apoptosis, but sensitizes to TNF-induced necroptosis. The RHIM and caspase 8 interaction domains of R1 collaborate to prevent RIP3-dependent steps and enable both herpesviruses to deflect host cell death machinery that would cut short infection. In mouse cells, HSV1 infection by itself triggers necroptosis by driving RIP3 protein kinase activity. HSV1 R1 contributes to the activation of RIP3 adaptor function in mice, a popular host animal for experimental infection. Based on these studies, infection of RIP3-kinase inactive mice should be explored in models of pathogenesis and latency. The necrotic death pathway that is suppressed during infection in the natural host becomes a cross-species barrier to infection in a non-natural host.

Gelsolin, NF-κB, and p53 expression in clear cell renal cell carcinoma: Impact on outcome

OBJECTIVES

To examine the prognostic significance of Gelsolin, NF-κB, and p53 in clear cell renal cell carcinoma (CRCC), which has an unpredictable behavior and tendency for recurrence and metastasis.

MATERIALS AND METHODS

Immunohistochemistry was performed on 100 consecutive cases of CRCC using antibodies against Gelsolin, NF-κB, and p53. Tumors were grouped by nuclear grade (NG) as low NG (NG1, 2) or high NG (NG3, 4), and by pathological stage as localized (pT1, 2) or locally invasive (pT3, 4). Clinical stage was grouped as early stage (stage I, II) or late stage (stage III, IV). Evaluation was based on cytoplasmic (NF-κB(Cyt)) and nuclear (NF-κB(Nuc)) expression for NF-κB, nuclear expression for p53, membranous and cytoplasmic expression for Gelsolin.

RESULTS

Gelsolin expression correlated with high NG (p = 0.001), metastasis (p = 0.003), late stage (p = 0.008), and cancer death (p = 0.001). NF-κB(Cyt) expression correlated with high NG (p = 0.002), perirenal invasion (p = 0.010), local invasion (p = 0.020), and late stage (p= 0.003). NF-κB(Nuc) expression failed to predict the prognosis of CRCC. p53 expression correlated with high NG (p = 0.045), lymphovascular invasion (p = 0.05), metastasis (p = 0.001), late stage (p = 0.028), and cancer death (p = 0.034). However, only Gelsolin was found to correlate with disease-specific survival, (p = 0.006), and neither NF-κB nor p53 showed such relation.

CONCLUSION

Expressions of Gelsolin, NF-κB(Cyt), and p53 associated with aggressive behavior of CRCC, while Gelsolin expression specifically indicated poor disease-specific survival. The results of the present study served to determine biomarkers for predicting high-risk patients with CRCC, expected to show aggressive phenotype.

New miRNA profiles accurately distinguish renal cell carcinomas and upper tract urothelial carcinomas from the normal kidney

Background

Upper tract urothelial carcinomas (UT-UC) can invade the pelvicalyceal system making differential diagnosis of the various histologically distinct renal cell carcinoma (RCC) subtypes and UT-UC, difficult. Correct diagnosis is critical for determining appropriate surgery and post-surgical treatments. We aimed to identify microRNA (miRNA) signatures that can accurately distinguish the most prevalent RCC subtypes and UT-UC form the normal kidney.

Methods and Findings

miRNA profiling was performed on FFPE tissue sections from RCC and UT-UC and normal kidney and 434 miRNAs were significantly deregulated in cancerous vs. the normal tissue. Hierarchical clustering distinguished UT-UCs from RCCs and classified the various RCC subtypes among them. qRT-PCR validated the deregulated expression profile for the majority of the miRNAs and ROC analysis revealed their capability to discriminate between tumour and normal kidney. An independent cohort of freshly frozen RCC and UT-UC samples was used to validate the deregulated miRNAs with the best discriminatory ability (AUC>0.8, p<0.001). Many of them were located within cytogenetic regions that were previously reported to be significantly aberrated. miRNA targets were predicted using the miRWalk algorithm and ingenuity pathway analysis identified the canonical pathways and curated networks of the deregulated miRNAs. Using the miRWalk algorithm, we further identified the top anti-correlated mRNA/miRNA pairs, between the deregulated miRNAs from our study and the top co-deregulated mRNAs among 5 independent ccRCC GEO datasets. The AB8/13 undifferentiated podocyte cells were used for functional assays using luciferase reporter constructs and the developmental transcription factor TFCP2L1 was proved to be a true target of miR-489, which was the second most upregulated miRNA in ccRCC.

Conclusions

We identified novel miRNAs specific for each RCC subtype and UT-UC, we investigated their putative targets, the networks and pathways in which they participate and we functionally verified the true targets of the top deregulated miRNAs.

Meta-analysis identifies NF-κB as a therapeutic target in renal cancer

OBJECTIVE

To determine the expression patterns of NF-κB regulators and target genes in clear cell renal cell carcinoma (ccRCC), their correlation with von Hippel Lindau (VHL) mutational status, and their association with survival outcomes.

METHODS

Meta-analyses were carried out on published ccRCC gene expression datasets by RankProd, a non-parametric statistical method. DEGs with a False Discovery Rate of < 0.05 by this method were considered significant, and intersected with a curated list of NF-κB regulators and targets to determine the nature and extent of NF-κB deregulation in ccRCC.

RESULTS

A highly-disproportionate fraction (~40%; p < 0.001) of NF-κB regulators and target genes were found to be up-regulated in ccRCC, indicative of elevated NF-κB activity in this cancer. A subset of these genes, comprising a key NF-κB regulator (IKBKB) and established mediators of the NF-κB cell-survival and pro-inflammatory responses (MMP9, PSMB9, and SOD2), correlated with higher relative risk, poorer prognosis, and reduced overall patient survival. Surprisingly, levels of several interferon regulatory factors (IRFs) and interferon target genes were also elevated in ccRCC, indicating that an 'interferon signature' may represent a novel feature of this disease. Loss of VHL gene expression correlated strongly with the appearance of NF-κB- and interferon gene signatures in both familial and sporadic cases of ccRCC. As NF-κB controls expression of key interferon signaling nodes, our results suggest a causal link between VHL loss, elevated NF-κB activity, and the appearance of an interferon signature during ccRCC tumorigenesis.

CONCLUSIONS

These findings identify NF-κB and interferon signatures as clinical features of ccRCC, provide strong rationale for the incorporation of NF-κB inhibitors and/or and the exploitation of interferon signaling in the treatment of ccRCC, and supply new NF-κB targets for potential therapeutic intervention in this currently-incurable malignancy.