Activity In Renal Cell Carcinoma Research Articles

LINC00493-encoded microprotein SMIM26 exerts anti-metastatic activity in renal cell carcinoma.

Human microproteins encoded by long non-coding RNAs (lncRNA) have been increasingly discovered, however, complete functional characterization of these emerging proteins is scattered. Here, we show that LINC00493-encoded SMIM26, an understudied microprotein localized in mitochondria, is tendentiously downregulated in clear cell renal cell carcinoma (ccRCC) and correlated with poor overall survival. LINC00493 is recognized by RNA-binding protein PABPC4 and transferred to ribosomes for translation of a 95-amino-acid protein SMIM26. SMIM26, but not LINC00493, suppresses ccRCC growth and metastatic lung colonization by interacting with acylglycerol kinase (AGK) and glutathione transport regulator SLC25A11 via its N-terminus. This interaction increases the mitochondrial localization of AGK and subsequently inhibits AGK-mediated AKT phosphorylation. Moreover, the formation of the SMIM26-AGK-SCL25A11 complex maintains mitochondrial glutathione import and respiratory efficiency, which is abrogated by AGK overexpression or SLC25A11 knockdown. This study functionally characterizes the LINC00493-encoded microprotein SMIM26 andestablishes its anti-metastatic role in ccRCC, and therefore illuminates the importance of hidden proteins in human cancers.

The role of TGR5 as an onco-immunological biomarker in tumor staging and prognosis by encompassing the tumor microenvironment.

The relationship between G protein-coupled bile acid receptor 1 (TGR5, GPBAR1) and, specifically, cancer has been studied in in vivo and in vitro experiments, but there is still a lack of pan-cancer analysis to understand the prognostic significance and functioning mechanism of TGR5 in different cancer-driving oncogenic processes. Here, we used Gene Expression Integration, Human Protein Atlas, and The Cancer Genome Atlas (TCGA) to perform a pan-cancer analysis of the role of TGR5 in all 33 tumors. In all TCGA tumors, the TGR5 gene expression has been assessed, and we found that the high TGR5 gene expression in most cancers is associated with poor prognosis of overall survival for cancers such as glioblastoma multiforme (p = 0.0048), kidney renal papillary cell carcinoma (p = 0.033), lower grade glioma (p = 0.0028), thymoma (p = 0.048), and uveal melanoma (p = 0.004), and then the lower expression of TGR5 was linked with poor prognosis in cervical squamous cell carcinoma and endocervical adenocarcinoma (p = 0.014), malignant mesothelioma (MESO) (p = 0.048), sarcoma (p = 0.018), and skin cutaneous melanoma (p = 0.0085). The TGR5 expression was linked with the immune infiltration level of the macrophage M2_TIDE and was also associated with DNA methylation in ovarian and breast cancers. The regulation of hormone secretion, Rap1 pathway, osteoclast differentiation, and bile acid pathway was involved in the functional mechanism of TGR5. Besides, gene expressions were different in different tumors detected by RT-PCR, and cell activity experiments have also found that TGR5 can increase the activity of renal cell carcinoma and reduce the activity of skin cancer and osteosarcoma cells. In this investigation, the aim was to assess the comprehensive overview of the oncogenic roles of TGR5 in all TCGA tumors using pan-analysis.

Distinct Predictive Immunogenomic Profiles of Response to Immune Checkpoint Inhibitors and IL2: A Real-world Evidence Study of Patients with Advanced Renal Cancer.

Next-generation IL2 agents, designed for improved tolerability over traditional HD-IL2 (aldesleukin), are in clinical development. Retrospective molecular tumor profiling of patients treated with HD-IL2 or anti-PD-1 therapy provides insights into genomic characteristics of therapy response. This study revealed common and distinct immune-related predictive response markers for IL2 and anti-PD-1 therapy which may play a role in therapy guidance, and rational combination strategies for these agents.

Circular RNA circVAMP3 promotes aerobic glycolysis and proliferation by regulating LDHA in renal cell carcinoma

Metabolic dysfunction is seen in cancer cells where increased glycolysis provides energy for growth. Circular RNAs (circRNAs) are thought to assist in glucose metabolism and the switch to glycolysis. Through screening, we found that circVAMP3 was necessary for both glycolytic and proliferative activities in renal cell carcinoma (RCC). Furthermore, circVAMP3 expression was elevated in RCC patients in correspondence with TNM stage. Mechanistically, circVAMP3 was observed to interact directly with lactate dehydrogenase A (LDHA) and modulate its activity. The circVAMP3–LDHA interaction facilitated LDHA phosphorylation at tyrosine 10 (Y10) catalyzed by the upstream kinase fibroblast growth factor receptor type 1 (FGFR1). Therefore, this study reveals a novel molecular mechanism by which circVAMP3 promotes glycolysis and proliferation through regulating the enzymatic activity of glycolytic enzyme, suggesting that circVAMP3 may represent an RCC biomarker and treatment target.

CircRNA_001895 promotes sunitinib resistance of renal cell carcinoma through regulation of apoptosis and DNA damage repair

Sunitinib, an inhibitor of receptor tyrosine kinase, possesses anti-tumor activity in renal cell carcinoma (RCC) through its anti-angiogenic effects. However, patients with advanced RCC are resistant to sunitinib. Dysregulated circRNAs has been shown to be associated with drug resistance in various tumors. However, little is known about the effect of circRNA_001895 on sunitinib resistance of RCC. First, the expression of circRNA_001895 was found to be higher in sunitinib-resistant RCC tissues than chemosensitive tumor tissues. Half maximal inhibitory concentration of sunitinib-resistant RCC cells (786-O/R and ACHN/R) was higher than sunitinib-sensitive 786-O and ACHN cells. CircRNA_001895 was also upregulated in 786-O/R and ACHN/R cells. Second, data from colony formation and flow cytometry analysis showed that knockdown of circRNA_001895 suppressed cell proliferation and promoted cell apoptosis in 786-O/R and ACHN/R cells. Moreover, the protein expression of phosphorylated histone H2AX (γH2AX) was enhanced, while phosphorylated DNA-dependent protein kinase (p-DNA-PK) and Rad51 were reduced in 786-/R and ACHN/R by knockdown of circRNA_001895. Lastly, knockdown of circRNA_001895 conferred sensitivity of in vivo tumor growth to sunitinib. In conclusion, circRNA_001895 was implicated in the sunitinib resistance in RCC through regulation of apoptosis and DNA damage repair, suggesting that circRNA_001895 might be a potential therapeutic target for advanced RCC.

Diverse Roles of G‐Protein‐Coupled Receptor 40 (GPR40/FFA1) and GPR120 (FFA4) in the Regulation of Cell Growth and Motile Activities in Renal Cell Carcinoma (RCC)

Renal cell carcinoma (RCC) is the 16th most common cancer worldwide with roughly 400,000 new cases diagnosed annually and approximately half of those leading to mortality. Even though the 5-year survival rate for early-stage RCC is 80%-90%, it is only 5% for the patients with metastasis. Unfortunately, anticancer drugs that are used to treat RCC are proven to be useful for only a small number of patients. Therefore, it is crucial to discover the novel molecular pathways underlying RCC to develop better therapies. The G protein-coupled receptors GPR40 and GPR120, also referred to as free fatty acid receptor 1 (FFA1) and 4 (FFA4), respectively, are activated by medium- to long-chain free fatty acids. Emerging evidence suggests that GPR40 and GPR120 are implicated in the proliferation, invasiveness, and apoptosis of various tumor cells, however, the precise mechanisms of GPCRs signaling events leading to the modifications in cancer cell growth and migration are still scarce, and the roles of these receptors in RCC are unstudied to date. Here, for the first time, we reveal the effects of GPR40 and GPR120 agonism on cell proliferation and migration in metastatic tumor-derived renal cancer cells. The present study used in vitro techniques including cell proliferation assay, wound-healing assay, and transwell migration assay to investigate the functions of GPR40 and GPR120 on the proliferative and migration capacities of the RCC cell line. The human renal cancer cell line ACHN was obtained from the American Type Culture Collection (ATCC). Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was performed to confirm the presence of GPR40 and GPR120 transcripts. Cell proliferation was assessed by plating 50,000 cells per well, followed by treatment with GPR40 and GPR120 agonists and antagonists as noted for 6 days. Cells were counted every 24 hours. For the wound-healing assay, 100,000 cells were plated on a 48-well plate and a scratch-made through the center. The time to wound healing was assessed at 0, 24, 36, and 48 hours. For migration assays, cells were plated in the top chamber of a transwell plate and cells migrated was counted by crystal violet staining after 16 hr. Using selective GPR40 and GPR120 agonists and antagonists, our results demonstrate that GPR40 enhanced and GPR120 suppressed cell proliferation, suggesting that the opposite effects of GPR120 and GPR40 are involved in the cell growth activity. The wound-healing assay revealed that both GPR40 and GPR120 agonism markedly covered the wounded area compared to vehicle-controls, an effect that is blocked by a selective GPR40 and GPR120 antagonist, respectively. In transwell migration assay, GPR40 negatively and GPR120 positively affect the ability of single cells to respond to the chemoattractant; further confirming their involvement in the acquisition of migratory properties in RCC cell. Our present results suggest that GPR40/120-mediated signaling may be involved in the regulation of renal cancer tumorigenesis and progression on the cellular level, and mechanistic studies are underway to assess the cellular cascades that are influenced by GPR40 and GPR120.

Optimized Combination of HDACI and TKI Efficiently Inhibits Metabolic Activity in Renal Cell Carcinoma and Overcomes Sunitinib Resistance.

Simple SummaryTo ameliorate the situation for kidney cancer patients and to broaden the application of available drugs, we initiated this research to enhance the anti-cancer activity through combination treatment. There is an unmet need for innovative treatment strategies and optimized drug combinations haven proven to be an adequate solution. We identified a four-drug combination of two histone deacetylate and two tyrosine kinase inhibitors that is effective in sunitinib-naïve and -resistant human renal cell carcinoma cells. Through our research, we demonstrated the superior anti-cancer activity of an optimized drug combination in comparison to single drugs, while maintaining a good safety/selectivity profile. We anticipate that the development and use of well-established drug combinations will be enforced offering personalized and more diverse treatment options in clinical conditions.Clear cell renal cell carcinoma (ccRCC) is characterized by high histone deacetylase (HDAC) activity triggering both cell motility and the development of metastasis. Therefore, there is an unmet need to establish innovative strategies to advance the use of HDAC inhibitors (HDACIs). We selected a set of tyrosine kinase inhibitors (TKIs) and HDACIs to test them in combination, using the validated therapeutically guided multidrug optimization (TGMO) technique based on experimental testing and in silico data modeling. We determined a synergistic low-dose three-drug combination decreasing the cell metabolic activity in metastatic ccRCC cells, Caki-1, by over 80%. This drug combination induced apoptosis and showed anti-angiogenic activity, both in original Caki-1 and in sunitinib-resistant Caki-1 cells. Through phosphoproteomic analysis, we revealed additional targets to improve the translation of this combination in 3-D (co-)culture systems. Cell–cell and cell–environment interactions increased, reverting the invasive and metastatic phenotype of Caki-1 cells. Our data suggest that our optimized low-dose drug combination is highly effective in complex in vitro settings and promotes the activity of HDACIs.

Morusin exerts anti-cancer activity in renal cell carcinoma by disturbing MAPK signaling pathways.

BackgroundRenal cell carcinoma (RCC) has gradually become a severe type of kidney malignant tumor, which warrants an urgent need for highly efficacious therapeutic agents. Morusin, a typical prenylated flavonoid, has been revealed to possess anticarcinogenic effects against several cancers by inhibiting cell proliferation and tumorigenesis.MethodsCells proliferation was examined by CCK-8. Migration assays were performed using a 24-well transwell chamber. Apoptotic cells were detected using the Annexin V PE/7-AAD apoptosis detection kit. Cell cycle analysis was carried out by flow cytometry. Western blotting and quantitative real time (qRT) PCR were used to exam the change of target gene in mRNA and protein level. Nude mouse xenograft experiments were performed to identify vivo function of morusin.ResultsHere, we evaluated the effect of morusin against RCC. We treated three RCC cell lines, 769-P, 786-O, and OSRC-2, with morusin to study its effects on cell growth, migration, apoptosis, cell cycle and cancer-related pathways. Additionally, we assessed the effects of morusin on tumor growth using a nude mouse model. Morusin could inhibit cell growth and migration, induce cell apoptosis and downregulate apoptosis-related proteins, and disturb the cell cycle arrest in the G1 phase. Additionally, morusin could suppress RCC tumorigenesis in vivo. Moreover, mitogen-activated protein kinase (MAPK) signal pathways were found to be involved in morusin-induced anti-cancer activity. P-p38 and P-JNK levels were up-regulated by morusin, while the ERK phosphorylation level was down-regulated.ConclusionsOur results show that morusin could inhibit the growth of RCC cells in vitro and in vivo through MAPK signal pathways. Thus, morusin could be a potential anti-cancer agent for RCC.

Pegylated Interleukin-10: Clinical Development of an Immunoregulatory Cytokine for Use in Cancer Therapeutics.

Interleukin-10 (IL-10) is a cytokine with anti-inflammatory properties, which induces activation and proliferation of antigen-activated intratumoral CD8+ T cells. This review discusses the evolution of pegylated IL-10 (pegilodecakin) from preclinical investigation through first-in-human studies in oncology. Pegilodecakin was evaluated across multiple advanced solid tumors in a large phase 1/1b trial alone and in combination with chemotherapy or anti-PD-1 antibodies. Pegilodecakin monotherapy had immunologic and clinical activity in renal cell carcinoma (RCC) and uveal melanoma. In combination with anti-PD-1 inhibitors, pegilodecakin increased the responses in RCC and lung cancer with efficacy agnostic to PD-L1 status and tumor mutational burden. Pegilodecakin with FOLFOX had activity in pretreated pancreatic cancer, instructing the ongoing randomized phase III trial of the combination versus FOLFOX. The increased half-life of pegilodecakin enabled compelling preclinical data for IL-10 which has now been confirmed by clinical activity in a variety of cancers. The ability of pegilodecakin to both exert anti-tumor immunity and inhibit tumor-associated inflammation characterizes the uniqueness of this cytokine therapy.

Multiregion Quantification of Extracellular Signal-regulated Kinase Activity in Renal Cell Carcinoma

To personalize treatment for renal cell carcinoma (RCC), it would be ideal to confirm the activity of druggable protein pathways within individual tumors. We have developed a high-resolution nanoimmunoassay (NIA) to measure protein activity with high precision in scant specimens (eg, fine needle aspirates [FNAs]). Here, we used NIA to determine whether protein activation varied in different regions of RCC tumors. Since most RCC therapies target angiogenesis by inhibiting the vascular endothelial growth factor (VEGF) receptor, we quantified phosphorylation of extracellular signal-regulated kinase (ERK), a downstream effector of the VEGF signaling pathway. In 90 ex vivo FNA biopsies sampled from multiple regions of 38 primary clear cell RCC tumors, ERK phosphorylation differed among patients. In contrast, within individual patients, we found limited intratumoral heterogeneity of ERK phosphorylation. Our results suggest that measuring ERK in a single FNA may be representative of ERK activity in different regions of the same tumor. As diagnostic and therapeutic protein biomarkers are being sought, NIA measurements of protein signaling may increase the clinical utility of renal mass biopsy and allow for the application of precision oncology for patients with localized and advanced RCC. Patient summaryIn this report, we applied a new approach to measure the activity of extracellular signal-regulated kinase (ERK), a key cancer signaling protein, in different areas within kidney cancers. We found that ERK activity varied between patients, but that different regions within individual kidney tumors showed similar ERK activity. This suggests that a single biopsy of renal cell carcinoma may be sufficient to measure protein signaling activity to aid in precision oncology approaches.

Development and evaluation of a novel series of Nitroxoline-derived BET inhibitors with antitumor activity in renal cell carcinoma

Small molecular inhibitors targeting BRD4 family proteins are emerging as promising therapies in many types of human malignancies. However, whether BRD4, as well as other BET family members, may serve as therapeutic targets in renal cell carcinoma (RCC) remains unknown. In this study, we found that both BRD2 and BRD4 were over-expressed in RCC tissues, knock-down both of which achieved potent anti-proliferative effects in RCC cells. A novel category of BET inhibitors, originated from an approved drug Nitroxoline, were synthesized and evaluated with biochemical and cellular assays, as well as the method of crystallography. The complex crystal structures of several compounds in this category with the first bromodomain of BRD4 (BRD4-BD1) were solved, revealing the binding mechanism and facilitating further structural optimizations. Among them, compound BDF-1253 showed an approximately four-fold improvement in BRD4 inhibition compared with the prototype Nitroxoline and had good selectivity for BET proteins against other bromodomain proteins or epi-enzymes in biochemical assays. Compound BDF-1253 efficiently suppressed the expression of BET downstream genes, impaired RCC cells viability via inducing cell cycle arrest and apoptosis, and decreased tumor growth in RCC xenografts. In summary, these results suggest that inhibition of BET family members has great therapeutic potentials in the treatment of RCC, and the novel series of BET inhibitors reported here are promising to become RCC drug candidates.

Epigenetic modifiers: activities in renal cell carcinoma.

Renal cell carcinomas (RCCs) are a diverse set of malignancies that have recently been shown to harbour mutations in a number of chromatin modifier genes - including PBRM1, SETD2, BAP1, KDM5C, KDM6A, and MLL2 - through high-throughput sequencing efforts. Current research focuses on understanding the biological activities that chromatin modifiers employ to suppress tumorigenesis and on developing clinical approaches that take advantage of this knowledge. Unsurprisingly, several common themes unify the functions of these epigenetic modifiers, particularly regulation of histone post-translational modifications and nucleosome organization. Furthermore, chromatin modifiers also govern processes crucial for DNA repair and maintenance of genomic integrity as well as the regulation of splicing and other key processes. Many chromatin modifiers have additional non-canonical roles in cytoskeletal regulation, which further contribute to genomic stability, expanding the repertoire of functions that might be essential in tumorigenesis. Our understanding of how mutations in chromatin modifiers contribute to tumorigenesis in RCC is improving but remains an area of intense investigation. Importantly, elucidating the activities of chromatin modifiers offers intriguing opportunities for the development of new therapeutic interventions in RCC.

Acquired resistance to temsirolimus is associated with integrin α7 driven chemotactic activity of renal cell carcinoma in vitro.

The mechanistic target of the rapamycin (mTOR) inhibitor, temsirolimus, has significantly improved the outcome of patients with renal cell carcinoma (RCC). However, development of temsirolimus-resistance limits its effect and metastatic progression subsequently recurs. Since integrin α7 (ITGA7) is speculated to promote metastasis, this investigation was designed to investigate whether temsirolimus-resistance is associated with altered ITGA7 expression in RCC cell lines and modified tumor cell adhesion and invasion. Caki-1, KTCTL-26, and A498 RCC cell lines were driven to temsirolimus-resistance by exposing them to temsirolimus over a period of 12 months. Subsequently, adhesion to human umbilical vein endothelial cells, to immobilized fibronectin, or collagen was investigated. Chemotaxis was evaluated with a modified Boyden chamber assay and ITGA7 expression by flow cytometry and western blotting. Chemotaxis significantly decreased in temsirolimus-sensitive cell lines upon exposure to low-dosed temsirolimus, but increased in temsirolimus-resistant tumor cells upon reexposure to the same temsirolimus dose. The increase in chemotaxis was accompanied by elevated ITGA7 at the cell surface membrane with simultaneous reduction of intracellular ITGA7. ITGA7 knock-down significantly diminished motility of temsirolimous-sensitive cells but elevated chemotactic activity of temsirolimus-resistant Caki-1 and KTCTL-26 cells. Therefore, ITGA7 appears closely linked to adhesion and migration regulation in RCC cells. It is postulated that temsirolimus-resistance is associated with translocation of ITGA7 from inside the cell to the outer surface. This switch forces RCC migration forward. Whether ITGA7 can serve as an important target in combatting RCC requires further investigation.

Axitinib in the treatment of renal cell carcinoma: design, development, and place in therapy.

Since 2005, the approved first-line treatment of metastatic renal cell carcinoma consists in tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial growth factor receptors (VEGFRs). Axitinib is an oral second-generation TKI and a potent VEGFR inhibitor with a half maximal inhibitory concentration for the VEGF family receptors 10-fold lower than other TKIs. Axitinib activity in renal cell carcinoma (RCC) patients has been studied in various settings and particularly as second-line treatment. In this setting, axitinib with clinically based dose escalation compared to sorafenib has demonstrated an improvement in progression-free survival in a randomized Phase III trial leading to US Food and Drug Administration approval. In the first-line setting, axitinib failed to demonstrate improved efficacy over sorafenib, but the field of RCC treatment is rapidly changing with novel TKIs as cabozantinib or the emergence of check point inhibitors as nivolumab and the place of axitinib in therapy is therefore challenged. In this review, we focus on axitinib pharmacological and clinical properties in RCC patients and discuss its place in the treatment of patients with RCC.

Association of NR1I2, CYP3A5 and ABCB1 genetic polymorphisms with variability of temsirolimus pharmacokinetics and toxicity in patients with metastatic bladder cancer.

Temsirolimus is a mammalian target of rapamycin (mTOR) inhibitor that exhibits antitumor activity in renal cell carcinoma and mantle cell lymphoma. The metabolism of temsirolimus and its active metabolite sirolimus mainly depends on cytochrome P450 3A4/5 (CYP3A4/A5) and the ABCB1 transporter. Differently from sirolimus, no pharmacogenetic study on temsirolimus has been conducted. Therefore, the aim of this pilot study was to identify genetic determinants of the inter-individual variability in temsirolimus pharmacokinetics and toxicity. Pharmacokinetic profiles were obtained for 16 patients with bladder cancer after intravenous infusion of 25mg temsirolimus. Non-compartmental analysis was performed to calculate the pharmacokinetic parameters of temsirolimus and sirolimus, its main metabolite. The presence of single nucleotide polymorphisms (SNPs) in CYP3A5, ABCB1 and in their transcriptional regulator NR1I2 (PXR) was assessed by genotyping. Non-parametric statistical tests were used to assess associations between candidate SNPs and temsirolimus pharmacokinetics and toxicity. The ratio between sirolimus AUC and temsirolimus AUC was 1.6-fold higher in patients who experienced serious toxic events (p=0.034). The frequency of adverse events was significantly higher in patients homozygous for the NR1I2-rs6785049 A allele (OR=0.065, p=0.04) or NR1I2-rs3814055 C allele (OR=0.032, p=0.006). These NR1I2 SNPs were also predictive of temsirolimus half-life and global exposure to temsirolimus and sirolimus. Finally, the effect of the ABCB1-rs1128503, ABCB1-rs2032582 and CYP3A5*3 SNPs on sirolimus pharmacokinetics was confirmed. Our findings suggest that SNPs of NR1I2 and its target genes CYP3A5 and ABCB1 are genetic determinants of temsirolimus pharmacokinetics and toxicity in patients with bladder cancer.

376 - CB-839, a selective glutaminase inhibitor, has anti-tumor activity in renal cell carcinoma and synergizes with everolimus and receptor tyrosine kinase inhibitors

376 - CB-839, a selective glutaminase inhibitor, has anti-tumor activity in renal cell carcinoma and synergizes with everolimus and receptor tyrosine kinase inhibitors

558P IL-1beta mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

558P IL-1beta mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

558P IL-1beta mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

558P IL-1beta mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

35P - IL-1b mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

35P - IL-1b mediates anti-progression activities in renal cell carcinoma by inducing MCP-1

Changes in expressions of ADAM9, 10, and 17 as well as α-secretase activity in renal cell carcinoma

BackgroundADAM9, 10, and 17 are a class of disintegrins and metallproteinases with α-secretase activity. There are conflicting results regarding the role(s) of ADAM9, 10, and 17 in carcinogenesis, and only a few studies have examined their levels and cellular localization in renal cell carcinoma (RCC). Studies examining changes in α-secretase activity in RCC compared to enzymatic activity of the uninvolved kidney are lacking. MethodA cross-sectional study was conducted in 56 patients undergoing radical nephrectomy after the diagnosis of RCC. α-Secretase activity was determined using flourogenic substrate in freshly frozen tumor tissues as well as similarly treated tissues from the neighboring kidney. Immunohistochemical analyses of ADAM9, 10, and 17 were also performed. Resultsα-Secretase activity decreased markedly in all types of RCC as compared to neighboring uninvolved kidney tissue having 5 to 10 times higher levels of α-secretase activity. Although type-dependent variations were observed, tumoral expressions of ADAMs, except for ADAM17, were lower in the tumors compared to that of neighboring tissues, but the changes in α-secretase activity were greater. In RCC tissue, ADAM9 expressions were localized in nuclear and cytoplasmic compartments, whereas ADAM10 and 17 were present predominately in the cytoplasm potentially explaining the markedly decreased enzyme activity. Membranous localization of ADAMs was noted in uninvolved kidney tissue. ConclusionsThe loss of α-secretase activity observed here in conjunction with previous findings argue against tumorigenic effects of ADAM9, 10, and 17 supporting that increased nuclear and cytoplasmic expression may be an attempt to compensate for loss of function.