Natural history and therapy of metastatic renal cell carcinoma: the role of interleukin-2

Bleeding metastasis of renal cell cancer to anal canal treated with radiation

Renal cell cancer (RCC) has the ability to metastasize to various organs, including the anal canal which is reported to be the rarest location. An 88-year-old male patient who had previously been treated for right RCC subsequently developed distant metastases to the prostate, lungs, and small bowel. Four years following nephrectomy, the patient presented with a bleeding anal mass which was excised and has been proven to be an anal canal metastasis of RCC. Eight months post excision, regrowth occurred. The patient underwent stereotactic ablative body radiotherapy resulting in satisfactory regression during the 2-month follow-up period, without episodes of bleeding. The treatment options for metastatic post-nephrectomy disease should be considered with a multidisciplinary approach in order to achieve satisfactory symptom relief.

Tumor-associated M2 macrophages in the immune microenvironment influence the progression of renal clear cell carcinoma by regulating M2 macrophage-associated genes

Background

Renal clear cell carcinoma (RCC) has negative prognosis and high mortality due to its early diagnosis difficulty and early metastasis. Although previous studies have confirmed the negative progression of RCC is closely related to M2 macrophages in tumor-associated macrophages (TAMs), the specific mechanism is still unknown.

Methods

We used immunofluorescence labeling and flow cytometry to detect the proportion of M2 macrophages in RCC tissues. And bioinformatics technique was used to obtain 9 M2 macrophage-related model genes, including SLC40A1, VSIG4, FUCA1, LIPA, BCAT1, CRYBB1, F13A, TMEM144, COLEC12. Using these genes, model formulas are constructed to devide samples into high and low risk groups, and then the overall survival (OS), progression-free survival (PFS) and Gene set enrichment analysis (GSEA) of the high and low risk groups were analyzed. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to measure the expression of model genes between normal kidney tissue and RCC tissue, as well as between HK-2 cell and 786-O cell. Besides, we induced the M2 differentiation of THP-1 cell, and then co-cultured with the RCC cell 786-O in transwell to observe what effect M2 macrophages will cause on the invasion, migration and the expression of model genes of RCC.

Results

Our study demonstrated M2 macrophages in RCC was about 2 folds that of normal renal tissue (P<0.0001) and M2 macrophages affected the prognosis of patients with RCC by affecting the co-expressed genes, which were mainly enriched in immune-related pathways. The results of in vitro experiments showed that in RCC tissues and 786-O cells, the model gene FUCA1 was down-regulated, and SLC40A1, VSIG4, CRYBB1 and LIPA were up-regulated. Besides, the results of co-culture showed that after 786-O co-culture with M2 macrophages, the ability of migration and invasion was promoted and the expressions of FUCA1, SLC40A1, VSIG4, CRYBB1, LIPA and TMEM144 were all up-regulated.

Conclusion

The proportion of tumor-associated M2 macrophages in RCC tissues is upregulated, and M2 macrophages promote the progression of RCC by regulating the expression of SLC40A1, VSIG4, FUCA1, LIPA, BCAT1, CRYBB1, F13A, TMEM144, COLEC12 genes, thereby affecting the prognosis of patients with RCC.

The Changing Landscape of Immunotherapy for Advanced Renal Cancer

The management of advanced renal cell carcinoma has advanced tremendously over the past decade, but most patients still do not receive durable clinical benefit from current therapies. Renal cellcarcinoma is an immunogenic tumor, historically with conventional cytokine therapies, such as interleukin-2 and interferon-α, and contemporarily with the introduction of immune checkpoint inhibitors. Now the central therapeutic strategy in renal cell carcinoma is combination therapies including immunecheckpoint inhibitors. In this Review, we look back on the historical changes in systemic therapy for advanced renal cell carcinoma, and focus on the latest developments and prospects in this field.

Interferons and Resistance Mechanisms in Tumors and Pathogen-Driven Diseases—Focus on the Major Histocompatibility Complex (MHC) Antigen Processing Pathway

Interferons (IFNs), divided into type I, type II, and type III IFNs represent proteins that are secreted from cells in response to various stimuli and provide important information for understanding the evolution, structure, and function of the immune system, as well as the signaling pathways of other cytokines and their receptors. They exert comparable, but also distinct physiologic and pathophysiologic activities accompanied by pleiotropic effects, such as the modulation of host responses against bacterial and viral infections, tumor surveillance, innate and adaptive immune responses. IFNs were the first cytokines used for the treatment of tumor patients including hairy leukemia, renal cell carcinoma, and melanoma. However, tumor cells often develop a transient or permanent resistance to IFNs, which has been linked to the escape of tumor cells and unresponsiveness to immunotherapies. In addition, loss-of-function mutations in IFN signaling components have been associated with susceptibility to infectious diseases, such as COVID-19 and mycobacterial infections. In this review, we summarize general features of the three IFN families and their function, the expression and activity of the different IFN signal transduction pathways, and their role in tumor immune evasion and pathogen clearance, with links to alterations in the major histocompatibility complex (MHC) class I and II antigen processing machinery (APM). In addition, we discuss insights regarding the clinical applications of IFNs alone or in combination with other therapeutic options including immunotherapies as well as strategies reversing the deficient IFN signaling. Therefore, this review provides an overview on the function and clinical relevance of the different IFN family members, with a specific focus on the MHC pathways in cancers and infections and their contribution to immune escape of tumors.

The key role of microRNA-766 in the cancer development

Cancer is caused by defects in coding and non-coding RNAs. In addition, duplicated biological pathways diminish the efficacy of mono target cancer drugs. MicroRNAs (miRNAs) are short, endogenous, non-coding RNAs that regulate many target genes and play a crucial role in physiological processes such as cell division, differentiation, cell cycle, proliferation, and apoptosis, which are frequently disrupted in diseases such as cancer. MiR-766, one of the most adaptable and highly conserved microRNAs, is notably overexpressed in several diseases, including malignant tumors. Variations in miR-766 expression are linked to various pathological and physiological processes. Additionally, miR-766 promotes therapeutic resistance pathways in various types of tumors. Here, we present and discuss evidence implicating miR-766 in the development of cancer and treatment resistance. In addition, we discuss the potential applications of miR-766 as a therapeutic cancer target, diagnostic biomarker, and prognostic indicator. This may shed light on the development of novel therapeutic strategies for cancer therapy.

Complementary roles of surgery and systemic treatment in clear cell renal cell carcinoma

Standard-of-care management of renal cell carcinoma (RCC) indisputably relies on surgery for low-risk localized tumours and systemic treatment for poor-prognosis metastatic disease, but a grey area remains, encompassing high-risk localized tumours and patients with metastatic disease with a good-to-intermediate prognosis. Over the past few years, results of major practice-changing trials for the management of metastatic RCC have completely transformed the therapeutic options for this disease. Treatments targeting vascular endothelial growth factor (VEGF) have been the mainstay of therapy for metastatic RCC in the past decade, but the advent of immune checkpoint inhibitors has revolutionized the therapeutic landscape in the metastatic setting. Results from several pivotal trials have shown a substantial benefit from the combination of VEGF-directed therapy and immune checkpoint inhibition, raising new hopes for the treatment of high-risk localized RCC. The potential of these therapeutics to facilitate the surgical extirpation of the tumour in the neoadjuvant setting or to improve disease-free survival in the adjuvant setting has been investigated. The role of surgery for metastatic RCC has been redefined, with results of large trials bringing into question the paradigm of upfront cytoreductive nephrectomy, inherited from the era of cytokine therapy, when initial extirpation of the primary tumour did show clinical benefits. The potential benefits and risks of deferred surgery for residual primary tumours or metastases after partial response to checkpoint inhibitor treatment are also gaining interest, considering the long-lasting effects of these new drugs, which encourages the complete removal of residual masses.

Comparison of cytoreductive partial versus radical nephrectomy in metastatic renal cell carcinoma: To be on the horns of a dilemma

BACKGROUND

Cytoreductive radical nephrectomy (cRN) with immunotherapy is the treatment of choice in patients with metastatic renal cell carcinoma (mRCC). Limited data are available on the role of cytoreductive partial nephrectomy (cPN) in mRCC. This study is a systematic review and meta-analysis of the evidence regarding survival rates comparing cPN versus cRN.

METHODS

PubMed/Medline, Scopus, Google Scholar, EMBASE, and the Cochrane Library were reviewed in December 2021 according to PRISMA. Four articles including 2669 patients were selected to enroll in the study. The identified reports were reviewed and their methodological quality was subjected to total quality assessment. The outcomes were cancer specific survival (CSS) and overall survival rate (OS).

RESULTS

Totally 2669 patients, 542 in cPN and 2127 in cRN groups enrolled in final analysis. Of the preoperative data, there were significant differences in preoperative size of tumor between cRN and cPN patients (p < 0.001), however Fuhrman grades were comparable between groups (low grade: p = 0.51, high grade: p = 0.76). There were comparable results in 1-year (p = 0.07), 2-year (p = 0.08), and 3-year (p = 0.71) CSS rates between cPN versus cRN. There was no significant difference between cPN versus cRN in OS rate (p = 0.61).

CONCLUSION

There are comparable results between cPN and cRN in CSS and OS rate. However, due to a lack of data, future study will need to do more extensive studies using prospectively recorded patient features to evaluate the cPN and cRN in the metastatic setting.

An Exploratory Analysis of Changes in Circulating Plasma Protein Profiles Following Image-Guided Ablation of Renal Tumours Provides Evidence for Effects on Multiple Biological Processes

Simple Summary

Ablation techniques use extremely hot or cold temperatures to kill small cancers. It is now known that in addition to killing the cancer cells, the ablation treatment may stimulate an immune response in patients against the cancer cells, acting like a vaccine. As a result, there is now interest in combining ablation together with drugs that target the immune system of patients with cancer to enhance the effects of both treatments. In order to develop such combined treatments and test them in clinical trials, we need to understand more about their effects so trials can be optimally designed to be most effective. We have analysed 164 circulating proteins in the blood from patients with small renal tumours undergoing ablation treatment to understand more about the effects of ablation on the patient, both at the level of the effects on the cancer cells and the response of the patients.

Abstract

Further biological understanding of the immune and inflammatory responses following ablation is critical to the rational development of combination ablation-immunotherapies. Our pilot exploratory study evaluated the circulating plasma protein profiles after image-guided ablation (IGA) of small renal masses to determine the resultant systemic effects and provide insight into impact both on the tumour and immune system. Patients undergoing cryotherapy (CRYO), radiofrequency ablation (RFA) or microwave ablation (MWA) for small renal tumours were recruited. Blood samples were obtained at four timepoints; two baselines prior to IGA and at 24 h and 1–3 months post-IGA, and a panel of 164 proteins measured. Of 55 patients recruited, 35 underwent ablation (25 CRYO, 8 RFA, 2 MWA) and biomarker measurements. The most marked changes were 24 h post-CRYO, with 29 proteins increasing and 18 decreasing significantly, principally cytokines and proteins involved in regulating inflammation, danger-associated molecular patterns (DAMPs), cell proliferation, hypoxic response, apoptosis and migration. Intra-individual variation was low but inter-individual variation was apparent, for example all patients showed increases in IL-6 (1.7 to 29-fold) but only 50% in CD27. Functional annotation analysis highlighted immune/inflammation and cell proliferation/angiogenesis-related clusters, with interaction networks around IL-6, IL-10, VEGF-A and several chemokines. Increases in IL-8, IL-6, and CCL23 correlated with cryoprobe number (p = 0.01, r_s = 0.546; p = 0.009, r_s = 0.5515; p = 0.005, r_s = 0.5873, respectively). This initial data provide further insights into ablation-induced biological changes of relevance in informing trial design of immunotherapies combined with ablation.

The Immunotherapy Revolution in Kidney Cancer Treatment: Scientific Rationale and First-Generation Results

The recent discovery of immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, including the treatment for renal cell carcinoma (RCC). Following the eras of cytokines and molecularly targeted therapies including vascular endothelial growth factor-directed agents and mammalian target of rapamycin (mTOR) inhibitors, ICIs have become the latest addition to the RCC armamentarium. To understand the scientific rationale behind this revolution in RCC treatment, we have reviewed the fundamental discoveries underlying the transition from old (cytokines) to new (ICIs) immunotherapies. We summarize the pivotal trials (CheckMate 025, CheckMate 214, KEYNOTE-426, JAVELIN Renal 101, IMmotion151) of checkpoint inhibitors for clear cell RCC in various treatment settings. With the availability of many different combination therapies and many more currently under investigation, clear cell RCC treatment is becoming more complex. Patient preferences, disease volumes, and adverse event profiles are essential in determining which option is the best for an individual patient. In the future, biomarkers currently under development could guide these treatment decisions.

Targeted Demethylation of the PLOD2 mRNA Inhibits the Proliferation and Migration of Renal Cell Carcinoma

N6-methyladenosine (m⁶A) RNA modification is the most common internal mRNA modification in mammals and has been reported to play a key role in gene expression regulation. In this study, we detected a high level of m⁶A methylation of the PLOD2 3′-untranslated regions (3′UTR) in renal cell carcinoma (RCC). Furthermore, we found that the high expression level of PLOD2 was a prognostic indicator for patients with RCC. A dm⁶ACRISPR demethylation system was performed to accurately and specifically demethylate 3′UTR of PLOD2 and caused an inactivation of PLOD2 expression. Furthermore, we also performed many in vitro experiments to confirm that PLOD2 exerted tumor promoter effects by promoting tumor proliferation and migration. In conclusion, PLOD2 mRNA demethylated by dCas13b-ALKBH5 might provide a new light on the treatment for RCC.

Choice of Surgical Options in Kidney Cancer and Surgical Complications

Surgical resection of renal cell carcinoma plays a large role in the overall management of the disease. The gold standard for surgical management historically has been open or laparoscopic radical nephrectomy, however, evidence of equivalent oncologic efficacy with improved clinical outcomes has driven the use of nephron-sparing surgeries, especially for smaller and localized renal tumors. A role for surgery remains in metastatic RCC as well, but controversy exists as to which patients may benefit most from surgical intervention in addition to other systemic targeted therapies. This article focuses specifically on renal cell carcinoma, transitional cell carcinoma is not described here.

Development and validation of the prognostic value of the immune-related genes in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a highly heterogeneous tumor, resulting a challenge of developing target therapeutics. Not long ago, immune checkpoint blockade regimens combine with tyrosin kinase inhibitors have evolved frontline options in metastatic RCC, which implies arrival of the era of tumor immunotherapy. Studies have demonstrated immune-related genes (IRGs) could characterize tumor milieu and related to patient survival. Nevertheless, the clinical significance of classifier depending on IRGs in ccRCC has not been well established.

Methods

The R package limma, univariate and LASSO cox regression analysis were used to screen the prognostic related IRGs from TCGA database. Multivariate cox regression was utilized to establish a risk prediction model for candidate genes. Quantitative real-time PCR was used to confirm the expression of candidates in clinical samples from our institution. CIBERSORT algorithm and correlation analysis were applied to explore tumor-infiltrating immune cells signature between different risk groups. A clinical nomogram was also developed to predict OS by using the rms R package based on the risk prediction model and other independent risk factors. The ICGC data was used for external validation of either gene risk model or nomogram.

Results

We identified 382 differentially expressed immune related genes. Four unique prognostic IRGs (CRABP2, LTB4R, PTGER1 and TEK) were finally affirmed to associate with tumor survival independently and utilized to establish the risk score model. All candidates’ expression was successfully laboratory confirmed by q-PCR. CIBERSORT analysis implied patients in unfavorable-risk group with high CD8 T cell, regulatory T cell and NK cell infiltration, as well as high expression of PD-1, CTLA4, TNFRSF9, TIGIT and LAG3. A nomogram combined IRGs risk score with age, gender, TNM stage, Fuhrman grade, necrosis was further generated to predict of 3- and 5-year OS, which exhibited superior discriminative power (AUCs were 0.811 and 0.795).

Conclusions

Our study established and validated a survival prognostic model system based on 4 unique immune related genes in ccRCC, which expands knowledge in tumor immune status and provide a potent prediction tool in future.

ATF3 Suppresses Growth and Metastasis of Clear Cell Renal Cell Carcinoma by Deactivating EGFR/AKT/GSK3β/β-Catenin Signaling Pathway

Background

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignant cancers in East Asia, with high incidence and mortality. Accumulating evidence has shown that ATF3 is associated with tumor progression.

Methods

Using qPCR, the expression of ATF3 was detected in 93 patients with ccRCC, including 24 paired normal and tumor tissues, which were used to further compare ATF3 expression through western blotting and immunohistochemistry. Lentivirus was used for the overexpression or knockdown of ATF3, and the consequent alteration in function was analyzed through CCK8 assay, colony formation assay, wound healing assay, invasion assay, and flow cytometry. The potential mechanism affected by ATF3 was analyzed through gene set enrichment analysis (GSEA) and verified using western blotting, invasion assay, or immunofluorescence staining. Furthermore, a xenograft mouse model was used to assess the function of ATF3 in vivo.

Results

ATF3 expression was significantly decreased in ccRCC compared to that in adjacent normal tissues. Through gain- and loss-of-function experiments performed in an in vitro assay, we found that ATF3 could regulate ccRCC cell proliferation, cycle progression, migration, and invasion. In the in vivo study, the xenograft mouse model revealed that ATF3 overexpression can inhibit the growth of ccRCC. Moreover, the mechanism analysis showed that suppression of ATF3 could lead to an increase the expression of β-catenin and promote β-catenin transfer to the nucleus, and might be affected by EGFR/AKT/GSK3β signaling.

Conclusion

ATF3 could be utilized as an independent protective factor to inhibit the progression of ccRCC. Potential treatment strategies for ccRCC include targeting the ATF3/EGFR/AKT/GSK3β/β-catenin signaling pathway.

Androgen receptor decreases renal cell carcinoma bone metastases via suppressing the osteolytic formation through altering a novel circEXOC7 regulatory axis

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) has gender differences, with the androgen receptor (AR) linked positively with metastasis to the lung. Its linkage to ccRCC bone metastases (RBMs), however, remains unclear.

METHODS

In the current study, five human RCC and five RCC bone metastasis tissues were deeply sequenced using Arraystar human circRNA V2.0 microarray. We conducted gain-of-function screening in vitro and in vivo to elucidate the AR's role in the RBM. Loss/gain-of-function was also implemented to verify the roles of related non-coding RNAs and proteins.

RESULTS

We uncovered that RBM also has a gender difference showing higher AR expression may be linked to fewer RBMs, which might involve suppressing osteolytic formation. Mechanism dissection indicates that AR can decrease the circular RNA EXOC7 (circEXOC7), expression via enhancing transcription of DHX9, a regulatory protein in circRNA biogenesis. The circEXOC7 can sponge/suppress miR-149-3p resulting in suppressing the CSF1 expression by directly binding to the 3'UTR region of CSF1 mRNA. Results from clinical epidemiological surveys also found that AR has a positive correlation with miR-149-3p and a negative correlation with CSF1 in AR-positive ccRCC tissues. Preclinical studies with Balb/c nude mouse model also validated that targeting this newly verified AR/DHX9/circEXOC7/miR-149-3p/CSF1 signaling via altering circEXOC7 or AR could lead to suppressing the RBM progression.

CONCLUSIONS

These data showed that AR/DHX9/circEXOC7/miR-149-3p/CSF1 signaling acts as a valuable feature in the bone metastasis of renal cancer, which may benefit in suppressing the RBM progression.

Solitary synchronous gastric metastasis of renal cell carcinoma

INTRODUCTION

There have been some reports describing metastasis to the stomach from renal cell carcinomas. However, there are few reports describing solitary synchronous gastric metastasis of renal cell carcinomas.

CASE PRESENTATION

The patient was a 70-year-old woman who underwent an upper gastrointestinal endoscopy to examine her progressive weight loss. There was a submucosal tumor in the stomach, which was biopsied. The gastric tumor was pathologically proven to be a metastatic clear cell renal cell carcinoma. Furthermore, contrast-enhanced computed tomography showed right renal cell carcinoma invading the renal vein (cT3aN0M0). The patient underwent right radical nephrectomy and endoscopic resection for the treatment of the primary renal cancer and the gastric metastatic lesion, respectively. The resected specimen of the stomach had a clear resection margin.

CONCLUSION

Endoscopic resection for early stage gastric metastatic lesions of renal cell carcinomas is a reasonable approach because it is a minimally invasive surgical technique.

Androgen receptor modulates metastatic routes of VHL wild-type clear cell renal cell carcinoma in an oxygen-dependent manner

Recent studies indicated that the androgen receptor (AR) plays important roles in modulating metastasis of VHL-mutant clear cell renal cell carcinoma (ccRCC). However, the precise mechanisms of AR roles in VHL wild-type (VHL-wt) ccRCC, remain unclear. Here we found that AR interacted with VHL to modulate the metastasis of VHL-wt ccRCC via an oxygen-dependent manner. Mechanism dissection revealed that AR could transcriptionally suppress the miR-185-5p expression in the presence of functional VHL-wt protein under a normoxic condition, which might then result in increasing the expression of VEGF-A and VEGF-C via targeting the 3'UTR of mRNAs at a post-transcriptional level. In contrast, under a hypoxic condition, AR could increase miR-185-5p expression to suppress VEGF-C expression, yet this miR-185-5p effect on VEGF-A was reversed via AR's positive regulation on the HIF2α-increased VEGF-A expression that resulted in increasing VEGF-A in the VHL-wt RCC cells. These distinct AR functions under different oxygen conditions may involve the VHL-impacted ubiquitination and nuclear localization of AR. The differential regulation of VEGF-A vs VEGF-C by AR may then result in differential impacts on the ccRCC metastatic destinations of VHL-wt ccRCC cells under different oxygen conditions. These finer mechanisms may help in the development of a novel therapy to better suppress the ccRCC progression under different oxygenization conditions.

Adjuvant Therapy for Localized High-Risk Renal Cell Carcinoma

This article reviews the use of adjuvant therapies for prevention of recurrence following resection of clinically localized renal cell carcinoma (RCC). Clinical trials evaluating adjuvant therapy for RCC have focused primarily on the use of tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors, which had improved outcome in patients with metastatic disease. However, all but 1 trial found no difference in disease-free survival in the adjuvant setting and none improved overall survival.

Medicaid Expansion Did not Improve Time to Treatment for Young Patients With Metastatic Renal Cell Carcinoma

INTRODUCTION

The absence of health insurance coverage has been associated with worse outcomes for patients with metastatic renal cell carcinoma (mRCC). Medicaid expansion in the United States was an important provision of the Affordable Care Act, which increased the number of low-income individuals eligible for Medicaid starting in January 2014 in several states. The effect of Medicaid expansion on access to healthcare for patients with mRCC is unknown.

MATERIALS AND METHODS

We performed a retrospective cohort study of 6844 patients aged < 65 years with mRCC at diagnosis within the National Cancer Database. We compared the time to treatment and the rates of no insurance before (2012-2013) and after (2015-2016) expansion between patients living in states that had and had not expanded Medicaid using difference-in-difference (DID) analyses. DIDs were calculated using linear regression analysis with adjustment for sociodemographic covariates.

RESULTS

The rate of no insurance did not change in the expansion states compared with the nonexpansion states (DID, -0.55%; 95% confidence interval, -3.32% to 2.21%; P = .7). The percentage of patients receiving treatment within 60 days of diagnosis had increased in the expansion states from 43% to 49% and in the nonexpansion states from 42% to 46% after expansion. No change was found in treatment within 60 days of diagnosis among all patients (DID, 2.81%; 95% confidence interval, -2.61% to 8.22%; P = .3).

CONCLUSIONS

Medicaid expansion was not associated with improved healthcare access for patients with mRCC as reflected by timely treatment. Future work should assess the association between Medicaid expansion and oncologic outcomes.

Metastasis of renal cell carcinoma to urinary bladder: A rare case report with review of literature

Metachronous metastatic renal cell carcinoma (RCC) to bladder is rare incidence. We report a case of RCC with metachronous metastasis to the urinary bladder occurring 2 years postradical nephrectomy. In a follow-up for the past 1 year, the patient is doing well. To the best of our knowledge, this case is the second case of bladder metastasis from RCC in the Indian literature. We reviewed literature and discuss the histopathological features of bladder metastasis of RCC.

Immune checkpoint inhibitors: The linchpins of modern immunotherapy

Immune checkpoint inhibitors (ICIs) have revolutionized our approach to cancer treatment in the past decade. While monoclonal antibodies to CTLA-4 and PD-1/PD-L1 have produced remarkable and durable responses in a subset of patients, the majority of patients will still develop primary or adaptive resistance. With complex mechanisms of resistance limiting the efficacy of checkpoint inhibitor monotherapy, it is critical to develop combination approaches to allow more patients to benefit from immunotherapy. In this review, I approach the current landscape of ICI research from the perspective of sarcomas, a rare group of bone and soft tissue cancers that have had limited benefit from checkpoint inhibitor monotherapy, and little investigation of biomarkers to predict responses. By surveying the various mechanisms of resistance and treatment modalities being explored in other solid tumors, I outline how ICIs will undoubtedly serve as the critical foundation for future directions in modern immunotherapy.

Key Factors in Clinical Protocols for Adoptive Cell Therapy in Melanoma

Adoptive cell therapy (ACT) with autologous tumor infiltrating lymphocytes (TIL) has been studied for patients with advanced metastatic cancers (primarily melanoma) for decades and has changed significantly during that period. Treatment with TIL includes ex vivo cell activation and expansion followed by re-infusion of these cells into the patient. After cell infusion, patients receive Interleukin-2 (IL-2). Objective response rates up to 52% have been seen in patients with metastatic melanoma. Efforts to improve TIL therapy include better selection and expansion of tumor-reactive lymphocytes, optimization of IL-2 or other T cell activating cytokine dosing, and, potentially, genetic manipulation of the immune cell product. Here we describe methods involved in the collection, expansion, and treatment with TIL for patients with metastatic melanoma.

Molecular biology and targeted therapy in metastatic renal cell carcinoma

The treatment of metastatic renal cell carcinoma is challenging as it has proven to be relatively resistant to conventional oncological treatments. An improved understanding of the molecular biology of renal cell carcinoma has led to the development of a number of targeted therapies in metastatic renal cell carcinoma. This includes vascular endothelial growth factor inhibitors, tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors and most recently immune checkpoint inhibitors. This article will review the mechanisms of development and progression of renal cell carcinoma as well as the mechanisms of current approved treatments in metastatic disease.

Level of evidence: Not applicable for this multicentre audit.

Synchronous inhibition of mTOR and VEGF/NRP1 axis impedes tumor growth and metastasis in renal cancer

Clear cell renal cell carcinoma (ccRCC) is known for its highly vascular phenotype which is associated with elevated expression of vascular endothelial growth factor A (VEGF), also known as vascular permeability factor (VPF). Accordingly, VEGF has been an attractive target for antiangiogenic therapies in ccRCC. Two major strategies have hitherto been utilized for VEGF-targeted antiangiogenic therapies: targeting VEGF by antibodies, ligand traps or aptamers, and targeting the VEGF receptor signaling via antibodies or small-molecule tyrosine-kinase inhibitors (TKIs). In the present article we utilized two entirely different approaches: targeting mammalian target of rapamycin (mTOR) pathway that is known to be involved in VEGF synthesis, and disruption of VEGF/Neuroplin-1 (NRP1) axis that is known to activate proangiogenic and pro-tumorigenic signaling in endothelial and tumor cells, respectively. Everolimus (E) and a small-molecule inhibitor EG00229 (G) were used for the inhibition of mTOR and the disruption of VEGF/NRP1 axis, respectively. We also exploited a liposomal formulation decorated with a proprietary tumor-targeting-peptide (TTP) to simultaneously deliver these two agents in a tumor-targeted manner. The TTP-liposomes encapsulating both Everolimus and EG00229 (EG-L) demonstrated higher in vitro and in vivo growth retardation than the single drug-loaded liposomes (E-L and G-L) in two different ccRCC models and led to a noticeable reduction in lung metastasis in vivo. In addition, EG-L displayed remarkable inhibition of tumor growth in a highly aggressive syngeneic immune-competent mouse model of ccRCC developed in Balb/c mice. Taken together, this study demonstrates an effective approach to achieve improved therapeutic outcome in ccRCC.

Cabozantinib use in metastatic renal cell carcinoma patients in clinical practice: Evaluation of dosing patterns, tolerability, and outcomes compared to clinical trials

INTRODUCTION

Despite first-line approval in metastatic renal cell carcinoma (mRCC), the tyrosine kinase inhibitor cabozantinib is associated with frequent treatment-limiting side effects. Dose reductions in published trials of the drug and in clinical practice are commonplace. We analyzed our institution's real-world experience with cabozantinib dosing in patients with mRCC to assess strategies to improve tolerability and patient outcomes.

OBJECTIVES

The purpose of our study is to retrospectively analyze dose intensity, tolerability, and duration of exposure in mRCC patients who received cabozantinib at our institution.

METHODS

In this retrospective, single-center chart review, we identified 35 adult patients who received at least one cycle cabozantinib for mRCC during a two-year period. Dosing patterns were reviewed for each patient to allow calculation of median dose intensity and median duration of exposure.

RESULTS

The median dose intensity for cabozantinib was 55.4% and the median actual daily dose was 33.2 mg. Median duration of cabozantinib exposure was 10.4 months. Several alternative dosing strategies were employed with 60% of patients requiring at least one dose intervention to manage toxicities.

CONCLUSIONS

Patients in this analysis received a median actual daily dose of 33.4 mg, less than the reported median doses in the METEOR and CABOSUN trials. However, our median duration of cabozantinib treatment was 10.4 months compared to 8.3 months and 6.5 months in these respective trials. Further investigation is warranted to determine if alternative dosing strategies and lower median actual daily doses produce survival results comparable to published clinical trials.

TIP-B1 promotes kidney clear cell carcinoma growth and metastasis via EGFR/AKT signaling

Kidney clear cell carcinoma (KIRC) is the most prevalent kidney malignancy. Accumulating evidence shows that high expression of TIP-B1 correlates with development of tumor progression. However, the detailed functions of TIP-B1 in the KIRC remain to be further elucidated. Here, we firstly found TIP-B1 expression was significantly increased in KIRC compared with adjacent normal tissues. What’s more, higher expression of TIP-B1 were correlated with aggressive clinico-pathological characteristics. In vitro assay found TIP-B1 knockdown dramatically inhibited KIRC cells proliferation, migration and invasion. In vivo assay found down regulated TIP-B1 could suppress tumor growth and metastasis. Mechanism analysis indicated that TIP-B1 could bind EGFR and suppress EGFR degradation, then promoted EGF-induced AKT signaling. Together, TIP-B1 could be applied as an independent risk factor to predict KIRC progression and metastasis. Targeting TIP-B1 might be a new potential therapeutic strategy for KIRC treatment.

Co-delivery of everolimus and vinorelbine via a tumor-targeted liposomal formulation inhibits tumor growth and metastasis in RCC

Background

Renal cell carcinoma (RCC) is notorious for its resistance towards chemotherapy and radiation therapy in general. Combination therapy is often helpful in alleviating the resistance mechanisms by targeting multiple signaling pathways but is usually more toxic than monotherapy. Co-encapsulation of multiple therapeutic agents in a tumor-targeted drug delivery platform is a promising strategy to mitigate these limitations.

Methods

A tumor-targeted liposomal formulation was prepared using phospholipids, cholesterol, DSPE-(PEG)₂₀₀₀-OMe and a proprietary tumor-targeting-peptide (TTP)-conjugated lipopeptide. An efficient method was optimized to encapsulate everolimus and vinorelbine in this liposomal formulation. Single drug-loaded liposomes were also prepared for comparison. Finally, the drug-loaded liposomes were tested in vitro and in vivo in two different RCC cell lines.

Results

The tumor-targeted liposomal formulation demonstrated excellent tumor-specific uptake. The dual drug-loaded liposomes exhibited significantly higher growth inhibition in vitro compared to the single drug-loaded liposomes in two different RCC cell lines. Similarly, the dual drug-loaded liposomes demonstrated significantly higher suppression of tumor growth compared to the single drug-loaded liposomes in two different subcutaneous RCC xenografts. In addition, the dual drug-loaded liposomes instigated significant reduction in lung metastasis in those experiments.

Conclusion

Taken together, this study demonstrates that co-delivery of everolimus and vinorelbine with a tumor-targeted liposomal formulation is an effective approach to achieve improved therapeutic outcome in RCC.

Long-term patient survival after the surgical treatment of bone and soft-tissue metastases from renal cell carcinoma

Aims

The aims of this study were to evaluate the long-term outcome of surgery for bone or soft-tissue metastases from renal cell carcinoma (RCC) and to determine factors that affect prognosis.

Patients and Methods

Between 1993 and 2014, 58 patients underwent surgery for bone or soft-tissue metastases from RCC at our hospital. There were 46 men and 12 women with a mean age of 60 years (25 to 84). The mean follow-up period was 52 months (1 to 257). The surgical sites included the spine (33 patients), appendicular skeleton (ten patients), pelvis (eight patients), thorax (four patients), and soft tissue (three patients). The surgical procedures were en bloc metastasectomy in 46 patients (including 33 patients of total en bloc spondylectomy (TES)) and intralesional curettage in 12 patients. These patients were retrospectively evaluated for factors associated with prognosis.

Results

The one-, three-, five-, ten-, and 15-year overall survival (OS) rates were 89%, 75%, 62%, 48%, and 25%, respectively. The median survival time (MST) was 127 months for en bloc metastasectomy and 54 months for intralesional curettage and bone grafting. The median survival time was 127 months for the spine, 140 months for lesions of the appendicular skeleton, and 54 months for the pelvis. Multivariate analysis showed that non-clear cell type RCC and metastases to more than two sites were independent risk factors for a poor prognosis.

Conclusion

Patients with bone or soft-tissue metastases from a RCC have a reasonable prognosis, making surgical resection a viable option even in patients in whom the metastases are advanced. Cite this article: Bone Joint J 2018;100-B:1241-8.

Molecular Recognition and In-Vitro-Targeted Inhibition of Renal Cell Carcinoma Using a DNA Aptamer

Renal cell carcinoma (RCC) is the most common malignant tumor of the urinary system, and it has a high frequency of local invasion and distant metastasis. Although multiple advances have been made in the diagnosis and therapy of RCC, the vast majority of patients with metastatic RCC remain incurable. In this study, an aptamer named SW-4 against RCC 786-O cells was identified from a known sequence pool. The identified aptamer exhibited high binding affinity for target cells with dissociation constants in the nanomolar range. Binding analysis revealed that SW-4 only bound to RCC 786-O cells, but not HEK293T cells or human proximal tubular HK-2 cells, indicating that SW-4 has excellent binding selectivity. By sequence optimization, the 26-nt truncated SW-4b demonstrated improved binding affinity, and it was internalized into target cells via caveolae-mediated endocytosis in a temperature-dependent manner. Furthermore, fluorescence imaging confirmed that SW-4b accumulated at tumor sites in 786-O xenograft nude mice models and specifically recognized clinical RCC tissues. Meanwhile, SW-4b inhibited proliferation of 786-O cells by arresting cell cycle progression at the S phase. Taken together, these results indicate that SW-4b is a potential candidate for development into a novel tool for diagnosis and targeted therapy of RCC.

Imaging and Management of Intrathoracic Renal Cell Carcinoma Metastases

OBJECTIVE

Renal cell carcinoma (RCC) has a propensity to metastasize to the chest, with the lungs being the most common distant metastatic site. The histologic subtype of RCC has implications for prognosis.

CONCLUSION

Significant advances have been made in the management of metastatic RCC, both in systemic and locoregional therapies. The aim of this article is to review appearances of intrathoracic metastases from RCC and to discuss treatment considerations.

Metastatic renal cell carcinoma initially presenting with hematochezia and subsequently with vaginal bleeding: a case report

Background

We report an unusual case of a synchronous rectal and metachronous vaginal metastatic renal cell carcinoma.

Case presentation

A 78-year-old woman presented with hematochezia and a colonoscopy revealed a metastatic clear-cell renal cell carcinoma rectal polyp biopsy-proven. Abdominal computed tomography identified a 9.0-cm left renal mass with renal vein thrombosis, for which she underwent a laparoscopic radical nephrectomy. Histopathological examination confirmed a pT_3a clear-cell renal cell carcinoma. Seven months later, the patient presented with vaginal bleeding. Physical examination revealed a vaginal polypoid mass and biopsy confirmed a clear-cell renal cell carcinoma metastasis.

Conclusions

This case represents unusual manifestations of metastatic renal cell carcinoma and is a reminder of the wide spectrum of clinical course of this disease.

Therapy to target renal cell carcinoma using 131I-labeled B7-H3 monoclonal antibody

B7-H3 is a tumor-associated antigen that plays a critical role in potential tumor-targeted therapy. In this study, we aimed to assess the radiobiological effect of ¹³¹I-labeled B7-H3 monoclonal antibody (¹³¹I-4H7) in nude mice with human renal cell carcinoma (RCC) and evaluate the effect of ¹³¹I-4H7 on RCC treatment. The radiobiological activity and tumor uptake of ¹³¹I-4H7, and its effect on tumor growth were measured. ¹³¹I-4H7 was absorbed by the tumor and reached its maximal uptake rate (3.32% injected dose [ID]/g) at 24 h, at which point the drug concentration in the tumor was 7.36-, 2.06-, 1.80-, and 2.78-fold higher than that in muscle, kidneys, liver, and heart, respectively. Measurements and positron emission tomography–computed tomography imaging showed that tumor development was significantly inhibited by ¹³¹I-4H7. HE staining revealed that ¹³¹I-4H7 significantly injures tumor cells. Our results suggest that ¹³¹I-4H7 is markedly absorbed by the tumor and did suppress the development of RCC xenografted tumors in nude mice, which might provide a new candidate for antibody-mediated targeted radiotherapy in human RCC.

Pyrvinium Sensitizes Clear Cell Renal Cell Carcinoma Response to Chemotherapy Via Casein Kinase 1α-Dependent Inhibition of Wnt/β-Catenin

BACKGROUND

Aberrant Wnt/β-catenin activation has been shown to play essential roles in cancer, including renal cell carcinoma (RCC). In this work, we demonstrate that Wnt/β-catenin inhibition by a Food and Drug Administration-approved drug, pyrvinium, effectively targets clear cell RCC and enhances chemotherapy agent's efficacy.

MATERIALS AND METHODS

We performed in vitro cell culture assays and in vivo xenograft tumor model to evaluate the effects of pyrvinium alone and its combination with paclitaxel, and analyzed the underlying mechanism(s) of pyrvinium's action in RCC.

RESULTS

We show that pyrvinium inhibits growth and induces apoptosis via caspase pathway in a panel of RCC cell lines. It decreases β-catenin activity and its downstream Wnt-targeted genes transcription via axin-mediated β-catenin protein reduction. Overexpression of β-catenin completely reverses the effects of pyrvinium, demonstrating that β-catenin inhibition is required for pyrvinium's action in clear cell RCC. Furthermore, we found that pyrvinium failed to decrease β-catenin protein level and activity in casein kinase 1α (CK1α)-depleted clear cell RCC cells, demonstrating that pyrvinium inhibits β-catenin in a CK1α-dependent manner. Notably, decreased tumor growth and β-catenin levels were observed in clear cell RCC xenograft mouse model treated with pyrvinium. Combination of pyrvinium and paclitaxel resulted in greater efficacy in in vitro and in vivo.

CONCLUSIONS

Our findings suggest that pyrvinium is a useful addition to the treatment armamentarium for clear cell RCC. Our work also demonstrate that targeting Wnt/β-catenin is a potential therapeutic strategy in clear cell RCC.

MicroRNAs Associated with Von Hippel-Lindau Pathway in Renal Cell Carcinoma: A Comprehensive Review

Renal cell carcinoma (RCC) are the most common renal neoplasia and can be divided into three main histologic subtypes, among which clear cell RCC is by far the most common form of kidney cancer. Despite substantial advances over the last decade in the understanding of RCC biology, surgical treatments, and targeted and immuno-therapies in the metastatic setting, the prognosis for advanced RCC patients remains poor. One of the major problems with RCC treatment strategies is inherent or acquired resistance towards therapeutic agents over time. The discovery of microRNAs (miRNAs), a class of small, non-coding, single-stranded RNAs that play a crucial role in post-transcriptional regulation, has added new dimensions to the development of novel diagnostic and treatment tools. Because of an association between Von Hippel–Lindau (VHL) genes with chromosomal loss in 3p25-26 and clear cell RCC, miRNAs have attracted considerable scientific interest over the last years. The loss of VHL function leads to constitutional activation of the hypoxia inducible factor (HIF) pathway and to consequent expression of numerous angiogenic and carcinogenic factors. Since miRNAs represent key players of carcinogenesis, tumor cell invasion, angiogenesis, as well as in development of metastases in RCC, they might serve as potential therapeutic targets. Several miRNAs are already known to be dysregulated in RCC and have been linked to biological processes involved in tumor angiogenesis and response to anti-cancer therapies. This review summarizes the role of different miRNAs in RCC angiogenesis and their association with the VHL gene, highlighting their potential role as novel drug targets.

Androgen receptor increases hematogenous metastasis yet decreases lymphatic metastasis of renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a gender-biased tumor. Here we report that there is also a gender difference between pulmonary metastasis and lymph node metastasis showing that the androgen receptor (AR)-positive ccRCC may prefer to metastasize to lung rather than to lymph nodes. A higher AR expression increases ccRCC hematogenous metastasis yet decreases ccRCC lymphatic metastases. Mechanism dissection indicates that AR enhances miR-185-5p expression via binding to the androgen response elements located on the promoter of miR-185-5p, which suppresses VEGF-C expression via binding to its 3' UTR. In contrast, AR-enhanced miR-185-5p also promotes HIF2α/VEGF-A expression via binding to the promoter region of HIF2α. Together, these results provide a unique mechanism by which AR can either increase or decrease ccRCC metastasis at different sites and may help us to develop combined therapies using anti-AR and anti-VEGF-C compounds to better suppress ccRCC progression.The incidence of renal cell carcinoma is higher in males than in females due to the different androgen receptor signaling but the molecular mechanisms behind this gender bias are unclear. Here the authors show how androgen receptor expression influences the metastatic route through the regulation of miR-185 and VEGF isoforms.

Antibiotic ivermectin preferentially targets renal cancer through inducing mitochondrial dysfunction and oxidative damage

Renal cell carcinoma (RCC) is the most aggressive type of genitourinary cancer and highly resistant to current available therapies. In this work, we investigated the effects and mechanism of anti-parasitic agent ivermectin in RCC. We show that ivermectin significantly inhibits proliferation and induces apoptosis in multiple RCC cell lines that represent different histological subtypes and various mutation status. Importantly, ivermectin is significantly less or ineffective in normal kidney cells compared with RCC cells, demonstrating the preferential toxicity of ivermectin to RCC. Ivermectin also significantly inhibits RCC tumor growth in vivo. Mechanistically, ivermectin induces mitochondrial dysfunction via decreasing mitochondrial membrane potential, mitochondrial respiration and ATP production. As a consequence of mitochondrial dysfunction, oxidative stress and damage is detected in ivermectin treated RCC cells and xenograft mouse model. The rescue of ivermectin's effect by acetyl-l-Carnitine (ALCAR, a mitochondrial fuel) or antioxidant N-acetyl-l-cysteine (NAC) confirms mitochondria as the target of ivermectin in RCC cells. Compared to normal kidney cells, RCC cells have higher mitochondrial mass and respiration, and ATP production, which might explain the preferential toxicity of ivermectin to RCC. Our work suggest that ivermectin is a promising candidate for RCC treatment and targeting mitochondrial metabolism is an alternative therapeutic strategy for RCC.

DNA-methylation-mediated repression of miR-766-3p promotes cell proliferation via targeting SF2 expression in renal cell carcinoma

Aberrant expression of microRNA (miRNA) emerges as an important role in a wide range of human malignances, and further identification as well as validation of the change of these endogenous non-protein-coding transcripts is warranted. Here, we identify a novel epigenetic regulation of miR-766-3p and investigate its biological function as well as clinical significance in renal cell carcinoma (RCC). Bisulfate analysis elucidates that the promoter of miR-766-3p is highly methylated in RCC tissues compared to non-tumorous tissues. Notably, the downregulation of miR-766-3p is obviously associated with clinical stage and worse prognosis in RCC patients. Upregulated miR-766-3p attenuates cell-cycle progression via targeting SF2 expression and additional SF2/P-AKT/P-ERK signaling pathway. Moreover, high level of SF2, as a novel oncoprotein in RCC, was significantly associated with poor survival in a large cohort of RCC specimens. Taken together, our study presents a road map for the prediction and validation of miR-766-3p/SF2 axis and thus imparts a therapeutic way for further RCC progression.

Clinicopathological significance of ganglioside DSGb5 expression in renal cell carcinoma

Disialosyl globopentaosylceramide (DSGb5) is a ganglioside originally isolated from tissue extracts of renal cell carcinoma (RCC) with metastasis. Previous in vitro experiments have suggested that DSGb5 promotes metastasis by enhancing the migration of RCC cells and downregulating NK cell cytotoxicity against RCC cells. In this study, we investigated the clinicopathological significance of DSGb5 expression in RCC and outcomes of RCC patients. A total of 156 RCC patients who underwent surgical treatments at our hospital from January 2007 through December 2012 were analyzed in this study. The expression of DSGb5 in RCC specimens was examined by immunohistochemical staining with monoclonal antibody 5F3. The immunostaining intensity of RCC tissues was assessed in comparison with that in benign renal tubules as an internal positive control. The relationship between DSGb5 expression and clinicopathological characteristics was investigated and recurrence free survival following surgery was evaluated. Microvascular invasion was observed in 68% (n = 19/28) and in 45% (n = 58/128) of the DSGb5 high expression group and low expression group, respectively (p = 0.031). Of 156 patients with a median follow up of 51 months, 18 patients (12%) developed metastasis following surgery. Patients in the DSGb5 high expression group showed significantly lower recurrence-free survival as compared with those in the DSGb5 low expression group (log-rank P = 0.047). In the present study, DSGb5 expression was associated with microvascular invasion in RCC tissues, and patients with DSGb5 high expression showed significantly lower recurrence-free survival rates. These findings suggest that DSGb5 expressed in RCC is correlated with metastasis and is a potential predictor for identifying patients who experience metastasis after surgery.

Dicer suppresses the malignant phenotype in VHL-deficient clear cell renal cell carcinoma by inhibiting HIF-2α

Both the von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF) pathway and microRNA (miRNA) regulation are important mechanisms underlying the development and progression of clear cell renal cell carcinoma (ccRCC). Here we demonstrate that VHL deficiency leads to downregulation of Dicer and, in turn, defects in the miRNA biogenesis machinery in ccRCCs. Dicer inhibited expression of HIF-2α, which was a direct target of Dicer-dependent miR-182-5p in VHL-deficient ccRCCs. Ectopic Dicer expression in VHL-deficient ccRCCs suppressed tumor growth and angiogenesis by inhibiting HIF-2α both in vitro and in vivo. Reduced Dicer mRNA levels served as an independent prognostic factor for poor survival in patients with VHL-deficient ccRCC. Our results indicate that downregulation of Dicer in VHL-deficient ccRCCs contributes to high levels of HIF-2α and a malignant phenotype, which suggests Dicer could be a useful therapeutic target for managing this disease.

Systemic Therapy in Metastatic Renal Cell Carcinoma

During the last two decades considerable advances have been made in the understanding of the biology of RCC. Although the best therapeutic options for patients with metastatic RCC have not been defined, it is apparent that use of immunomodulating cytokines like interferon-alpha and interleukin-2 either alone or combined with chemotherapeutic agents provides the best available results in routine clinical practice. Numerous studies have confirmed that objective tumour responses are seen only in a small fraction of patients (averagely in 15–20%). In spite of a lot of evidence that these treatments prolong survival, expectations of only 5–10% long-term survivals with complete and durable regression of tumours are realistic. Recently, some new promising investigational approaches have been reported. These may already in near future further improve overall treatment results.

Niclosamide suppresses renal cell carcinoma by inhibiting Wnt/β-catenin and inducing mitochondrial dysfunctions

PURPOSE

To investigate the effects of anthelminthic drug niclosamide in renal cell carcinoma (RCC) and the underlying mechanisms of its action.

METHODS

The effects of niclosamide on the proliferation and apoptosis of RCC cells were examined in vitro and in vivo by using MTS, colony formation assay, flow cytometry and xenograft cancer mouse model. Mechanism studies were performed by analyzing Wnt/β-catenin signaling and mitochondrial functions in a panel of RCC cell lines.

RESULTS

We show that niclosamide effectively targets two RCC cell lines through inhibiting proliferation and anchorage-independent colony formation, and inducing apoptosis. It also enhances the inhibitory effects of chemotherapeutic drug cisplatin in two independent in vivo RCC xenograft mouse models. Mechanistically, niclosamide decreases β-catenin levels and therefore suppresses Wnt/β-catenin activities. Overexpression of β-catenin partially reverses the inhibitory effects of niclosamide in RCC cells, demonstrating that besides β-catenin, other mechanisms are involved in niclosamide's anti-cancer activity. Indeed, we further show that niclosamide induces mitochondrial dysfunctions as shown by the decreased level of mitochondrial membrane potential and respiration, resulting in decreased ATP levels and increased reactive oxygen species (ROS) levels.

CONCLUSIONS

Our findings support the inhibitory effects of niclosamide in cancer and provide better understanding on its underlying mechanism. Our data suggests that niclosamide is a useful addition to the treatment armamentarium for RCC.

Protein Kinase RNA-Like Endoplasmic Reticulum Kinase-Mediated Bcl-2 Protein Phosphorylation Contributes to Evodiamine-Induced Apoptosis of Human Renal Cell Carcinoma Cells

We investigated the anticancer mechanism of evodiamine (EVO) against the viability of human A498 renal cell carcinoma (RCC) cells in vitro and in vivo. The in vitro study showed that EVO decreased the viability of A498 cells with the occurrence of apoptotic characteristics such as hypodiploid cells, DNA ladders, chromatin-condensed cells, and cleaved caspase (Casp)-3/poly(ADP ribose) polymerase (PARP) proteins. Pharmacological studies using chemical inhibitors of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) indicated that phosphorylation of the c-Jun N-terminal kinase (JNK) protein participated in EVO-induced cell death of A498 cells, and application of the JNK inhibitor, SP600125 (SP), inhibited EVO-induced cleavage of the Casp-3/PARP proteins and chromatin condensation according to Giemsa staining. EVO disruption of the mitochondrial membrane potential (MMP) with increased protein levels of the phosphorylated Bcl-2 protein (p-Bcl-2) was prevented by JNK inhibitors in A498 cells. A structure-activity relationship study showed that a methyl group at position 14 in EVO was important for its apoptotic effects and increased p-Bcl-2 protein in A498 cells. Furthermore, significant increases in the phosphorylated endoplasmic reticular stress protein, protein kinase RNA-like endoplasmic reticulum kinase (p-PERK at Thr980), by EVO were detected in A498 cells, and the PERK inhibitor, GSK2606414, significantly suppressed EVO-induced apoptosis, p-JNK, p-PERK, and cleaved PARP proteins. The in vivo study showed that EVO significantly reduced RCC growth elicited by a subcutaneous injection of A498 cells, and an increased protein level of p-PERK was observed according to an immunohistochemical analysis. Apoptosis by EVO was also demonstrated in other RCC cells such as 786-O, ACHN, and Caki-1 cells. This is the first study to demonstrate the anti-RCC effect of EVO via apoptosis in vitro and in vivo, and activation of JNK and PERK to induce Bcl-2 protein phosphorylation, which led to disruption of the MMP.

Infiltration of tumor-associated macrophages is involved in CD44 expression in clear cell renal cell carcinoma

Cancer stem‐like cells (CSC) or cancer‐initiating cells are now considered to be an important cell population related to cancer recurrence and the resistance to anti‐cancer therapy. Tumor‐associated macrophages (TAM) are a main component of stromal cells and are related to cancer progression in clear cell renal cell carcinoma (ccRCC). Because the detailed mechanisms allowing the maintenance of CSC in cancer tissues remain unclear, we investigated the relationship between TAM and CD44‐expressing cancer cells in ccRCC. CD44 was used as a marker for CSC, and CD163 and CD204 were used as markers for TAM. CD44‐positive cancer cells were detected in 37 of the 103 cases. Although statistical analysis showed no relationship between CD44‐positive cancer cells and the clinical course, the distribution of CD44‐positive cancer cells was significantly associated with a high density of TAM. Our in vitro study using RCC cell lines and human macrophages demonstrated that CD44 expression was upregulated by direct co‐culture with macrophages. Silencing of TNF‐alpha on macrophages abrogated the upregulation of CD44 expression in cancer cells. Macrophage‐induced CD44 overexpression was also suppressed by NF‐κB inhibitors. These results suggest that TNF‐alpha derived from TAM is linked to CD44 overexpression via NF‐κB signaling in ccRCC.

Ganglioside, disialosyl globopentaosylceramide (DSGb5), enhances the migration of renal cell carcinoma cells

About one third of renal cell carcinoma (RCC) patients exhibit metastasis upon initial presentation. However, the molecular basis for RCC metastasis is not fully understood. A ganglioside, disialosyl globopentaosylceramide (DSGb5), was originally isolated from RCC tissue extracts, and its expression is correlated with RCC metastatic potential. DSGb5 is synthesized by GalNAc α2,6-sialyltransferase VI (ST6GalNAcVI) and is expressed on the surface of RCC cells. Importantly, DSGb5 binds to sialic acid-binding Ig-like lectin-7 (Siglec-7) expressed on natural killer (NK) cells, thereby inhibiting NK-cell cytotoxicity. However, the role of DSGb5 in RCC progression remains obscure. To address this issue, we used ACHN cells derived from malignant pleural effusion of a patient with metastatic RCC. Using the limiting dilution method, we isolated three independent clones with different DSGb5 expression levels. Comparison of these clones indicated that the cloned cells with high DSGb5 expression levels exhibited greater migration potential, compared to the clone with low DSGb5 expression levels. In contrast, DSGb5 expression levels exerted no significant effect on cell proliferation. We then established the ACHN-derived cell lines that stably expressed siRNA against ST6GalNAcVI mRNA or control siRNA. Importantly, the ST6GalNAcVI-knockdown cells expressed low levels of DSGb5. We thus demonstrated the significantly decreased migration potential of the ST6GalNAcVI-knockdown cells with low DSGb5 expression levels, compared to the control siRNA-transfected cells expressing high DSGb5 levels, but no significant difference in the cell proliferation. Thus, DSGb5 expression may ensure the migration of RCC cells. We propose that DSGb5 expressed on RCC cells may determine their metastatic capability.

Prognostic Significance of Hypoxia-Inducible Factor Expression in Renal Cell Carcinoma: A PRISMA-compliant Systematic Review and Meta-Analysis

The prognostic value of hypoxia-inducible factor (HIF) in renal cell carcinoma (RCC) has been evaluated in a large number of studies, but the reports were inconsistent and remained inconclusive. Therefore, we conducted a systematic review and meta-analysis to clarify the significance of HIF expression in RCC prognosis. PubMed, Embase, Web of Science, Cochrane Library, EBSCO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Biological Abstracts were searched for eligible studies. Hazard ratio (HR) data for overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS) with 95% confidence interval (CI) related to the expression status of HIF-1α or HIF-2α detected by immunohistochemistry were all extracted. Data were combined using a random- or fixed-effects model based on the corresponding inter-study heterogeneity. Subgroup analyses were also performed. A total of 14 studies composed of 1258 patients for HIF-1α evaluation and 619 patients for HIF-2α evaluation were included for further analysis. When initially analyzed as a whole, the HIF-1α expression was not significantly correlated with OS (HR 1.637, 95% CI 0.898-2.985, P = 0.108), CSS (HR 1.110, 95% CI 0.595-2.069, P = 0.744), and PFS (HR 1.113, 95% CI 0.675-1.836, P = 0.674). Similarly, HIF-2α expression was not significantly correlated with CSS (HR 1.597, 95% CI 0.667-3.824, P = 0.293) and PFS (HR 0.847, 95% CI 0.566-1.266, P = 0.417). However, subgroup analyses concerning subcellular localization of HIFs revealed that the high nuclear expression of HIF-1α was significantly associated with poor OS (HR 2.014, 95% CI 1.206-3.363, P = 0.007) and the high cytoplasmic expression of HIF -2α was significantly associated with poor CSS (HR 2.356, 95% CI 1.629-3.407, P = 0.000). The increased nuclear expression of HIF-1α and cytoplasmic expression of HIF-2α indicate unfavorable prognosis in RCC patients, which may serve as biomarkers for disease management.