CD31 angiogenesis and combined expression of HIF-1α and HIF-2α are prognostic in primary clear-cell renal cell carcinoma (CC-RCC), but HIFα transcriptional products are not: implications for antiangiogenic trials and HIFα biomarker studies in primary CC-RCC

Durvalumab plus pazopanib combination in patients with advanced soft tissue sarcomas: a phase II trial

We aimed to determine the activity of the anti-VEGF receptor tyrosine-kinase inhibitor, pazopanib, combined with the anti-PD-L1 inhibitor, durvalumab, in metastatic and/or recurrent soft tissue sarcoma (STS). In this single-arm phase 2 trial (NCT03798106), treatment consisted of pazopanib 800 mg orally once a day and durvalumab 1500 mg once every 3 weeks. Primary outcome was overall response rate (ORR) and secondary outcomes included progression-free survival (PFS), overall survival, disease control rate, immune-related response criteria, and safety. The ORR was 30.4% and the trial met the pre-specified endpoint. The median PFS was 7.7 months (95% confidence interval: 5.7-10.4). The common treatment-related adverse events of grades 3-4 included neutropenia (9 [19.1%]), elevated aspartate aminotransferase (7 [14.9%]), alanine aminotransferase (5 [10.6%]), and thrombocytopenia (4 [8.5%]). In a prespecified transcriptomic analysis, the B lineage signature was a significant key determinant of overall response (P = 0.014). In situ analysis also showed that tumours with high CD20+ B cell infiltration and vessel density had a longer PFS (P = 6.5 × 10-4) than those with low B cell infiltration and vessel density, as well as better response (50% vs 12%, P = 0.019). CD20+ B cell infiltration was identified as the only independent predictor of PFS via multivariate analysis. Durvalumab combined with pazopanib demonstrated promising efficacy in an unselected STS cohort, with a manageable toxicity profile.

Extracellular Vesicles Secreted by TGF-β1-Treated Mesenchymal Stem Cells Promote Fracture Healing by SCD1-Regulated Transference of LRP5

Bone fracture repair is a multiphased regenerative process requiring paracrine intervention throughout the healing process. Mesenchymal stem cells (MSCs) play a crucial role in cell-to-cell communication and the regeneration of tissue, but their transplantation is difficult to regulate. The paracrine processes that occur in MSC-derived extracellular vesicles (MSC-EVs) have been exploited for this study. The primary goal was to determine whether EVs secreted by TGF-β1-stimulated MSCs (MSCTGF-β1-EVs) exhibit greater effects on bone fracture healing than EVs secreted by PBS-treated MSCs (MSCPBS-EVs). Our research was conducted using an in vivo bone fracture model and in vitro experiments, which included assays to measure cell proliferation, migration, and angiogenesis, as well as in vivo and in vitro gain/loss of function studies. In this study, we were able to confirm that SCD1 expression and MSC-EVs can be induced by TGF-β1. After MSCTGF-β1-EVs are transplanted in mice, bone fracture repair is accelerated. MSCTGF-β1-EV administration stimulates human umbilical vein endothelial cell (HUVEC) angiogenesis, proliferation, and migration in vitro. Furthermore, we were able to demonstrate that SCD1 plays a functional role in the process of MSCTGF-β1-EV-mediated bone fracture healing and HUVEC angiogenesis, proliferation, and migration. Additionally, using a luciferase reporter assay and chromatin immunoprecipitation studies, we discovered that SREBP-1 targets the promoter of the SCD1 gene specifically. We also discovered that the EV-SCD1 protein could stimulate proliferation, angiogenesis, and migration in HUVECs through interactions with LRP5. Our findings provide evidence of a mechanism whereby MSCTGF-β1-EVs enhance bone fracture repair by regulating the expression of SCD1. The use of TGF-β1 preconditioning has the potential to maximize the therapeutic effects of MSC-EVs in the treatment of bone fractures.

A systematic review verified by bioinformatic analysis based on TCGA reveals week prognosis power of CAIX in renal cancer

BACKGROUND

Carbonic anhydrase IX (CAIX) protein has been correlated with progression and survival in patients with some tumors such as head and neck carcinoma. But renal cell carcinoma is an exception. The prognostic value of CAIX in RCC used to be associated with patients' survival according to published works. This study aimed to rectify the former conclusion.

METHODS

This study was registered in PROSPERO (CRD42020160181). A literature search of the PubMed, Embase, Cochrane library and Web of Science databases was performed to retrieve original studies until April of 2022. Twenty-seven studies, including a total of 5462 patients with renal cell carcinoma, were reviewed. Standard meta-analysis methods were used to evaluate the prognostic impact of CAIX expression on patient prognosis. The hazard ratio and its 95% confidence interval were recorded for the relationship between CAIX expression and survival, and the data were analyzed using Stata 11.0. Then we verify the meta-analysis resort to bioinformatics (TCGA).

RESULTS

Our initial search resulted in 908 articles in total. From PubMed, Embase, Web of Science electronic and Cochrane library databases, 493, 318 and 97 potentially relevant articles were discovered, respectively. We took the analysis between CA9 and disease-specific survival (HR = 1.18, 95% CI: 0.82-1.70, I2 = 79.3%, P<0.05), a subgroup then was performed to enhance the result (HR = 1.63, 95%CI: 1.30-2.03, I2 = 26.3%, P = 0.228); overall survival was also parallel with the former (HR = 1.13, 95%CI: 0.82-1.56, I2 = 79.8%, P<0.05), then a subgroup also be performed (HR = 0.90, 95%CI:0.75-1.07, I2 = 23.1%, P = 0.246) to verify the result; the analysis between CAIX and progression-free survival got the similar result (HR = 1.73, 95%CI:0.97-3.09, I2 = 82.4%, P<0.05), we also verify the result by subgroup analysis (HR = 1.04, 95%CI:0.79-1.36, I2 = 0.0%, P = 0.465); at last the relationship between CAIX and recurrence-free survival got the same result, too (HR = 0.99, 95%CI: 0.95-1.02, I2 = 57.8%, P = 0.050), the subgroup's result was also parallel with the former (HR = 1.01, 95%CI: 0.91-1.03, I2 = 0.00%, P = 0.704). To validate our meta-analysis, we took a bioinformatic analysis based on TCGA database, survival curve between low and high CAIX expression in four endpoints (DSS, OS, PFI, DFI) have corresponding P value (DSS:P = 0.23, OS:P = 0.77, PFI:P = 0.25, DFI:P = 0.78).

CONCLUSIONS

CAIX expression in patients with RCC is an exception to predict tumor survival. Both low CAIX expression and high expression are not associated with survivals in RCC patients.

The possible role of hypoxia in the affected tissue of relapsed clubfoot

Our aim was to study the expression of hypoxia-related proteins as a possible regulatory pathway in the contracted side tissue of relapsed clubfoot. We compared the expression of hypoxia-related proteins in the tissue of the contracted (medial) side of relapsed clubfoot, and in the tissue of the non-contracted (lateral) side of relapsed clubfoot. Tissue samples from ten patients were analyzed by immunohistochemistry and image analysis, Real-time PCR and Mass Spectrometry to evaluate the differences in protein composition and gene expression. We found a significant increase in the levels of smooth muscle actin, transforming growth factor-beta, hypoxia-inducible factor 1 alpha, lysyl oxidase, lysyl oxidase-like 2, tenascin C, matrix metalloproteinase-2, matrix metalloproteinase-9, fibronectin, collagen types III and VI, hemoglobin subunit alpha and hemoglobin subunit beta, and an overexpression of ACTA2, FN1, TGFB1, HIF1A and MMP2 genes in the contracted medial side tissue of clubfoot. In the affected tissue, we have identified an increase in the level of hypoxia-related proteins, together with an overexpression of corresponding genes. Our results suggest that the hypoxia-associated pathway is potentially a factor contributing to the etiology of clubfoot relapses, as it stimulates both angioproliferation and fibroproliferation, which are considered to be key factors in the progression and development of relapses.

Review of Prognostic Expression Markers for Clear Cell Renal Cell Carcinoma

Context: The number of prognostic markers for clear cell renal cell carcinoma (ccRCC) has been increasing regularly over the last 15 years, without being integrated and compared.

Objective: Our goal was to perform a review of prognostic markers for ccRCC to lay the ground for their use in the clinics.

Evidence Acquisition: PubMed database was searched to identify RNA and protein markers whose expression level was reported as associated with survival of ccRCC patients. Relevant studies were selected through cross-reading by two readers.

Evidence Synthesis: We selected 249 studies reporting an association with prognostic of either single markers or multiple-marker models. Altogether, these studies were based on a total of 341 distinct markers and 13 multiple-marker models. Twenty percent of these markers were involved in four biological pathways altered in ccRCC: cell cycle, angiogenesis, hypoxia, and immune response. The main genes (VHL, PBRM1, BAP1, and SETD2) involved in ccRCC carcinogenesis are not the most relevant for assessing survival.

Conclusion: Among single markers, the most validated markers were KI67, BIRC5, TP53, CXCR4, and CA9. Of the multiple-marker models, the most famous model, ClearCode34, has been highly validated on several independent datasets, but its clinical utility has not yet been investigated.

Patient Summary: Over the years, the prognosis studies have evolved from single markers to multiple-marker models. Our review highlights the highly validated prognostic markers and multiple-marker models and discusses their clinical utility for better therapeutic care.

Development of putrescine anchored nano-crystalsomes bearing doxorubicin and oleanolic acid: deciphering their role in inhibiting metastatic breast cancer

Angiogenesis driven tumor initiation and progression calls for a targeted therapy.

Hypoxia-inducible factor-1α in acute ischemic stroke: neuroprotection for better clinical outcome

Background

Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor which maintains cellular homeostasis in response to hypoxia. It can trigger apoptosis while stimulating angiogenesis process and decrease neurological deficit after an ischemic stroke. Up until now, this protein complex has not been widely investigated especially in stroke patient.

Objective

Here, we examined the potential of HIF-1α as a marker for neuroplasticity process after ischemic stroke.

Methods

Serum HIF-1α were measured in acute ischemic stroke patients. National Institute of Health Stroke Scale (NIHSS) were assessed on the admission and discharge day (between days 7 and 14). Ischemic stroke divided into 2 groups: large vessel disease (LVD, n = 31) and small vessel disease (SVD, n = 27). Statistical significances were calculated with Spearman rank test.

Results

A total of 58 patients, 31 with large artery atherosclerosis LVD and 27 with small vessel disease (SVD) were included in this study. HIF-1α level in LVD group was 0.5225 ± 0.2459 ng/mL and in SVD group was 0.3815 ± 0.121 ng/mL. HIF-1α was higher (p = 0.004) in LVD group than in SVD group. The initial NIHSS score in LVD group was 15.46 ± 2.61 and discharge NIHSS score was 13.31 ± 3.449. Initial NIHSS score in SVD group was 6.07 ± 1.82 and the discharge NIHSS was 5.703 ± 1.7055. In both SVD and LVD group, HIF-1α were significantly correlated with initial NIHSS (both p < 0.001) and discharge NIHSS (p < 0.0383 r = 0.94, p < 0.001, r = 0.93, respectively).

Conclusions

HIF-1α has a strong correlation with NIHSS and it may be used as predictor in acute ischemic stroke outcome.

Recent advances in the biology of tumour hypoxia with relevance to diagnostic practice and tissue-based research

In this review article, we examine the importance of low levels of oxygen (hypoxia) in cancer biology. We provide a brief description of how mammalian cells sense oxygen. The hypoxia-inducible factor (HIF) pathway is currently the best characterised oxygen-sensing system, but recent work has revealed that mammals also use an oxygen-sensing system found in plants to regulate the abundance of some proteins and peptides with an amino-terminal cysteine residue. We discuss how the HIF pathway is affected during the growth of solid tumours, which develop in microenvironments with gradients of oxygen availability. We then introduce the concept of 'pseudohypoxia', a state of constitutive, oxygen-independent HIF system activation that occurs due to oncogenic stimulation in a number of specific tumour types that are of immediate relevance to diagnostic histopathologists. We provide an overview of the different methods of quantifying tumour hypoxia, emphasising the importance of pre-analytic factors in interpreting the results of tissue-based studies. Finally, we review recent approaches to targeting hypoxia/HIF system activation for therapeutic benefit, the application of which may require knowledge of which hypoxia signalling components are being utilised by a given tumour. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Effect of CXCL12 and Its Receptors on Unpredictable Renal Cell Carcinoma

Chemokines are chemotactic cytokines that participate in numerous cell functions during hematopoiesis, morphogenesis, inflammation, neovascularization, and autoimmune diseases and cancer. They achieve their functions on binding to their G protein-coupled receptors. CXCL12, or stromal cell-derived factor-1, is a homeostatic chemokine secreted by fibroblasts, macrophages, and endothelial cells. It binds to CXC receptor 4 (CXCR4), also known as fusin (CD184), and alternate CXC receptor 7 (CXCR7), also known as atypical chemokine receptor 3. The CXCL12/CXCR4 axis participates in homing of hematopoietic stem cells and the development and production of B and T lymphocytes, plasmacytoid dendritic cells, and natural killer cells. It has been examined in > 20 different malignancies. CXCL12 plays an important role in tumor metastasis because it mediates the migration of tumor cells through the endothelial vessel wall and extracellular matrix. Its expression has been highest in common metastatic sites such as the brain, bone marrow, lymph nodes, and liver. CXCR4 is expressed by tumor cells in prostate, breast, lung, and other malignancies. Numerous studies have shown its correlation with a poor prognosis, recurrence-free survival, and poor overall survival. The present review has addressed the structure and function of CXCL12 and its receptors and the effect CXCL12/CXCR4 axis has on the pathogenesis and clinical development of renal cell carcinoma, one of the most aggressive cancers in urology, with limited therapeutic options.

Prognostic Significance of Cyclin D1 Expression in Renal Cell Carcinoma: a Systematic Review and Meta-analysis

Previous studies indicated that cyclin D1 shown the potential as a tumor biomarker. However, the prognostic value of cyclin D1 in renal cell carcinoma (RCC) remains controversial. This study investigated the correlation of cyclin D1 expression with the prognostic and clinicopathological features in RCC patients. We systematically searched the database of PubMed, Embase, Cochrane, and Web of Science updated on November 26, 2017. Eighteen studies with 2282 patients satisfied the inclusion criteria. Results demonstrated that cyclin D1 overexpression in RCC showed significant favorable prognostic impact on disease-free survival (DFS) (HR 0.57, 95% CI: 0.43-0.74) and disease-specific survival (DSS) (HR 0.59, 95% CI 0.41-0.85) without significant heterogeneity. In subgroup of clear cell RCC, the prognostic effect on DFS was robust and the pooled HR was 0.39 (95% CI: 0.27-0.57). However, no association between overall survival (OS) and cyclin D1 expression was observed. Stratified analysis in DFS studies by sample size, staining patterns race and metastasis status showed similar results. Otherwise, cyclin D1 overexpression predicted a reduced prevalence of high TNM stage (T3 + T4) (OR 0.63, 95% CI: 0.40-0.99), high-grade tumor (G3 + G4) (OR 0.51, 95% CI: 0.31-0.81) and large tumor size (OR 0.35, 95% CI: 0.19-0.62). Our meta-analysis indicated that cyclin D1 overexpression could predict the favorable prognosis in patients with RCC.

Tumor infiltrating mast cells determine oncogenic HIF-2α-conferred immune evasion in clear cell renal cell carcinoma

PURPOSE

Hypoxia-inducible factor 2α (HIF-2α) overexpression leads to activation of angiogenic pathways. However, little is known about the association between HIF-2α expression and anti-tumor immunity in clear cell renal cell carcinoma (ccRCC). We aimed to explore how HIF-2α influenced the microenvironment and the underlying mechanisms.

EXPERIMENTAL DESIGN

We immunohistochemically evaluated immune cells infiltrations and prognostic value of HIF-2α expression in a retrospective Zhongshan Hospital cohort of 280 ccRCC patients. Fresh tumor samples, non-tumor tissues and autologous peripheral blood for RT-PCR, ELISA and flow cytometry analyses were collected from patients who underwent nephrectomy in Zhongshan Hospital from September 2017 to April 2018. The TCGA KIRC cohort and SATO cohort were assessed to support our findings.

RESULTS

We demonstrated that ccRCC patients with HIF-2αhigh tumors exhibited reduced overall survival (p = 0.025) and recurrence-free survival (p < 0.001). Functions of CD8+ T cells were impaired in HIF-2αhigh patients. In ccRCC patients, HIF-2α induced the expression of stem cell factor (SCF), which served as chemoattractant for mast cells. Tumor infiltrating mast cells impaired anti-tumor immunity partly by secreting IL-10 and TGF-β. HIF-2α mRNA level adversely associated with immunostimulatory genes expression in KIRC and SATO cohorts.

CONCLUSIONS

HIF-2α contributed to evasion of anti-tumor immunity via SCF secretion and subsequent recruitment of mast cells in ccRCC patients.

The Clinicopathologic and Prognostic Value of Hypoxia-Inducible Factor-2α in Cancer Patients: A Systematic Review and Meta-Analysis

Hypoxia-inducible factor-2α (HIF2α) plays an important role in the development of tumors. However, the clinicopathologic and prognostic significance of HIF2α in cancer patients remains controversial. Therefore, we performed a meta-analysis to investigate the relationship between the HIF2α status and clinical outcome in human cancer. Studies were screened online using electronic databases. The pooled risk ratios or hazard ratios (HR) with their 95% confidence intervals (CI) were calculated from available publications. Subgroup analysis, sensitivity analysis, heterogeneity, and publication bias were also conducted. A total of 854 studies with 4,345 patients were obtained in this meta-analysis. The results indicated that the increased expression of HIF2α could predict unfavorable overall survival of cancer patients on both univariate analysis (HR, 1.64; 95% CI, 1.41-1.92, P < 0.001) and multivariate analysis (HR, 2.21; 95% CI, 1.70-2.87, P < 0.001). Moreover, HIF2α overexpression was associated closely with tumor differentiation, tumor-node-metastasis stage, and lymph metastasis. In addition, there was no obvious evidence for significant publication bias in this meta-analysis. Our study indicated that HIF2α might be an indicator of poor prognosis and clinicopathologic features of tumors and could serve as a novel biomarker in human cancer.

Rational design of temperature-sensitive blood-vessel-embolic nanogels for improving hypoxic tumor microenvironment after transcatheter arterial embolization

Transcatheter arterial embolization (TAE) plays an important role in clinical tumor therapy by accomplishing vessel-casting embolization of tumor arteries at all levels and suppressing tumor collateral circulation and vascular re-canalization. In this study, we describe smart blood-vessel-embolic nanogels for improving the anti-tumor efficacy of TAE therapy on hepatocellular carcinoma (HCC). Methods: In this study, an in vitro model composed of two microfluidic chips was used for simulating the tumor capillary network and analyzing artery-embolization properties. Also, blood-vessel-casting embolization of renal arteries was evaluated in normal rabbits. Using a VX2 tumor-bearing rabbit model, the therapeutic efficacy of TAE on HCC was investigated for tumor growth, necrosis, and proliferation. Neovascularization and collateral circulation were evaluated by immunofluorescent detection of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and CD31 following the TAE therapy of VX2 tumor-bearing rabbits. Results: Sufficient embolization of all eight levels of micro-channels was achieved in a tumor-vessel-mimetic model with two microfluidic chips using PIBI-2240, and was further confirmed in renal arteries of normal rabbit. Effective inhibition of tumor collateral circulation and vascular re-canalization was observed in VX2 tumor-bearing rabbits due to the reduced expression levels of HIF-1α, VEGF, and CD31. Conclusions: The exceptional anti-tumor effect of PIBI-2240 observed in this study suggested that it is an excellent blood-vessel-embolic material for tumor TAE therapy.

Upregulation of the alternative splicing factor NOVA2 in colorectal cancer vasculature

Background

Tumor-specific isoforms generated by alternative splicing (AS) are demonstrated to contribute to tumor progression and can represent potential biomarkers. NOVA2 is an AS factor that in physiological conditions regulates endothelial cells' (ECs) polarity and vessel lumen maturation, likely by mediating AS of apical-basal polarity regulators. However, NOVA2 expression in tumor ECs and its regulation have never been investigated.

Methods

To elucidate this, 40 colorectal cancer patients were enrolled and NOVA2 expression was investigated by immunohistochemistry in samples bearing both the normal mucosa and the tumor tissue.

Results

NOVA2 was found expressed in ECs of tumor vasculature and, importantly, it was upregulated in tumor ECs with respect to normal mucosa ECs in all cases (P<0.001). The same samples analyzed by immunohistochemistry for the expression HIF1α, a marker of hypoxia, showed a positive and significant association with NOVA2 levels (P=0.045). Of note, NOVA2 was upregulated by hypoxia also in an in vitro ECs model.

Conclusion

Our results provide, for the first time, evidence of NOVA2 expression and upregulation in tumor ECs and highlight hypoxia as a potential regulatory factor. These findings open a completely new perspective to study tumor vasculature and to uncover NOVA2 as a potential source of biomarkers and therapeutic targets based on AS isoforms.

Prognostic significance of the programmed death ligand 1 expression in clear cell renal cell carcinoma and correlation with the tumor microenvironment and hypoxia-inducible factor expression

Background

Clear cell renal cell carcinoma (ccRCC) is the most common renal malignancy. Hypoxia-inducible factors, HIF-1α and HIF-2α, are expressed in the majority of ccRCC. Targeting immune checkpoints with the blockade of PD-1 and its ligand PD-L1 reorganizes T-cell activity in tumor microenvironment and provides important antitumor responses. PD-L1 upregulation has been found to be hypoxia-inducible factor (HIF) dependent. Our aim is to demonstrate the association between PD-L1 and HIF expression and to reveal the role of PD-L1 in prognosis and its association with tumor microenvironment.

Methods

Surgical specimens from 145 patients diagnosed with ccRCC, who had undergone radical or partial nephrectomy, were retrospectively analyzed. Immunohistochemistry on tissue microarrays (TMA) was performed to demonstrate expressions of PD-L1, HIF-1α, and HIF-2α in tumor cells and PD-1, CD4, and CD8 in lymphocytes to assess lymphocyte density in tumor microenvironment.

Results

PD-L1 tumor cell expression was detected in 20/125 (13.8%) cases, which correlated with higher levels of PD-1, CD4, CD8 and HIF-2α expression. Low or high expression of HIF-1α was similar in PD-L1-positive cases. When PD-L1-positive cases were compared with negative ones, there was no significant difference in terms of prognostic factors. However, the number of WHO/ISUP grade 3–4 tumors was significantly higher in PD-L1-positive cases than in negative ones.

Conclusion

PD-L1 tumor cell expression is strongly associated with increased HIF-2α expression and presence of dense lymphocytic infiltration in ccRCCs. Our findings confirm that PD-L1 positivity is associated with high ISUP nucleolar grade. The association between PD-L1, HIF, and lymphocyte density in tumor microenvironment must be clarified and especially taken into account in combination treatment.

Prognostic Role of Hypoxia-Inducible Factor-2α Tumor Cell Expression in Cancer Patients: A Meta-Analysis

Hypoxia-inducible factor-2α (HIF-2α) plays an important role in tumor progression and metastasis. A number of studies have evaluated the correlation between HIF-2α overexpression and clinical outcome in cancer patients but yielded inconsistent results. To comprehensively and quantitatively summarize the evidence on the capability of HIF-2α to predict the prognosis of cancer patients with solid tumors, a meta-analysis was carried out. Renal cell carcinoma (CC-RCC) was separately analyzed due to an alternative mechanism of regulation. Systematic literature searches were performed in PubMed and Embase databases for relevant original articles until February 2018. Forty-nine studies with 6,052 patients were included in this study. The pooled hazard ratios (HRs) with corresponding confidence intervals were calculated to assess the prognostic value of HIF-2α protein expression in tumor cells. The meta-analysis revealed strong significant negative associations between HIF-2α expression and five endpoints: overall survival [HR = 1.69, 95% confidence interval (95% CI) 1.39-2.06], disease-free survival (HR = 1.87, 95% CI 1.2-2.92), disease-specific survival (HR = 1.57, 95% CI 1.06-2.34), metastasis-free survival (HR = 2.67, 95% CI 1.32-5.38), and progression-free survival (HR = 2.18, 95% CI 1.25-3.78). Subgroup analyses revealed similar associations in the majority of tumor sites. Overall, these data demonstrate a negative prognostic role of HIF-2α in patients suffering from different types of solid tumors.

Hypoxic marker CA IX and adhesion mediator β-catenin are downregulated by lymphocytic choriomeningitis virus persistent infection

Renal cell carcinoma is one of the most frequent cancer diseases with high resistance to radio- and chemotherapy. Mutation of VHL gene is frequent in these tumors leading to simulation of hypoxic conditions. Lymphocytic choriomeningitis virus, belonging to RNA viruses, is a neglected human pathogen and teratogen. We have found that infection of renal cell carcinoma cells by lymphocytic choriomeningitis virus strain MX causes a decrease of carbonic anhydrase IX protein and RNA level. Lower expression of carbonic anhydrase IX on the cell surface provides less target for carbonic anhydrase IX-targeted immunotherapy. What more, reduced levels of adhesion mediating protein β-catenin as well as E-cadherin, as a consequence of infection, suggest a possible increase in metastatic potential of cells infected by lymphocytic choriomeningitis virus strain MX. These results might help elucidate differences in patients susceptibility to immunotherapy directed against carbonic anhydrase IX or in developing new therapeutical strategies. Our data indicate that presence of infection can significantly affect patient response to cancer therapy.

Therapeutic effect of human umbilical cord-derived mesenchymal stem cells on injured rat endometrium during its chronic phase

BACKGROUND

Repair deficiency after endometrial injury is an important reason for intra-uterine adhesions, amenorrhea, and infertility in females. Bone marrow-derived mesenchymal stem cell (BMSC) transplantation is effective in repairing the damaged endometrium. However, the possibility of using umbilical cord-derived MSCs (UC-MSCs) to treat endometrial injury is rarely reported.

METHODS

Ethanol (95%) was injected into rat uterus to establish a model of endometrial injury. UC-MSCs were injected through the tail vein, either as a single, twice, or thrice administration. Functional restoration of the uterus was assessed by testing embryo implantation rates. Endometrial morphological alteration was observed by hematoxylin and eosin staining. Endometrial fibrosis, markers of epithelial and stromal cells of endometrium, cell proliferation and angiogenesis, and inflammatory factors were detected using immunohistochemistry, Western blotting, and quantitative reverse-transcription polymerase chain reaction.

RESULTS

Endometrial morphology and embryo implantation rates were significantly improved on day 8 of transplantation among single-, twice-, or thrice-administered rats. Moreover, UC-MSCs could alleviate fibrosis in general, and reduced the expression of fibrosis markers, α-smooth muscle actin (α-SMA) and transforming growth factor (TGF)-β. The cell proliferation marker Ki-67 had a positive expression in the injured endometrium after UC-MSC transplantation. The endometrial stromal marker vimentin and epithelial marker cytokeratin-19 (CK-19) expressions were visibly increased. The expression of vascular markers CD31, vascular endothelial growth factor (VEGF)A, and matrix metalloprotein (MMP)9 was generally upregulated. Proinflammatory factors interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-2 were significantly downregulated in the rats administered UC-MSCs twice and thrice.

CONCLUSIONS

UC-MSC transplantation contributed to the repair of endometrial injury and restoration of fertility, likely through the suppression of excessive fibrosis and inflammation, and enhancement of endometrial cell proliferation and vascular remodeling.

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.

Novel Angiogenesis Markers as Long-Term Prognostic Factors in Patients With Renal Cell Cancer

OBJECTIVE

To evaluate Ang-2 expression alone and in combination with expression of cell proliferation and cell survival markers (MIB-1 and Bcl-2) and angiogenesis markers (VEGFR3 and CD31), and the associations of these markers with renal cell cancer (RCC) in long-term survival.

PATIENTS AND METHODS

Our study included 224 patients with RCC who were treated before the availability of antiangiogenic agents between 1985 and 1995, at the Pirkanmaa Hospital District in Finland. All tumor samples were reclassified and reevaluated by an experienced uropathologist, and parallel tissue microarrays (TMA) were performed for immunohistochemical analysis. Kaplan-Meier's survival estimation method and Cox proportional hazards models were used for survival analysis.

RESULTS

The percentage of Ang-2 expression in the tumor area varied from 0.07 to 25.65. Ang-2 expression was significantly associated with the tumor grade and stage, as well as the MIB-1, Bcl-2, and VEGFR3 expression (P = .042, P = .019, P = .039, P = .013, and P = .005, respectively). The highest Ang-2 expression predicted better survival, P < .05. High Bcl-2 and low MIB-1 expression combined with Ang-2 expression was associated with better survival. Multivariate analysis showed poorer survival in patients with low Ang-2 or high MIB-1 expressions: HR 1.89, 95% CI 1.16 to 3.08, P = .010 and HR 2.20, 95% CI 1.36 to 3.54, P = .001, respectively.

CONCLUSIONS

Very high Ang-2 expression was associated with better survival in patients with RCC. Ang-2 expression correlated with tumor stage and grade, but it was still an independent prognostic factor in a multivariate analysis.

Neovascularity as a prognostic marker in renal cell carcinoma

Endothelial markers platelet and endothelial cell adhesion molecule (PECAM-1), cluster of differentiation (CD31) and endoglin (CD105) may be used to identify endothelium and activated endothelium, respectively, with the CD105/CD31 ratio used to measure neovascularity. This study investigated the hypothesis that neovascularity in renal cell carcinoma (RCC) is associated with more aggressive RCC tumors and can be used to predict oncological outcomes. Multiplexed immunohistochemistry using antibodies to detect endoglin and PECAM-1 was performed on tissue microarray of benign kidney samples and RCC tumors including clear cell, papillary, chromophobe, and collecting duct and unclassified tumors (combined for statistics), and multispectral imaging was used for analysis. The CD105/CD31 ratio was compared with clinical and pathologic features of RCC as well as clinical outcomes after surgery using Cox proportional hazards regression and Kaplan-Meier analysis. A total of 502 tumor samples and 122 normal kidney samples from 251 RCC patients were analyzed. The average CD105/CD31 expression ratio, an indicator of neovascularization, was increased in higher pathologic stage tumors (P< .0001). Among RCC morphotypes, the ratio was lower in papillary RCC morphotype tumors (P= .001) and higher in collecting duct/unclassified tumors (P= .0001) compared with clear cell RCC. Among nuclear grades, grade 4 RCC displayed a significantly elevated CD105/CD31 ratio (P< .0001). In multivariable analysis, increased neovascularity was associated with decreased overall survival (hazard ratio, 1.54 [95% confidence interval, 1.06-2.23]; P= .02). In patients receiving anti-vascular endothelial growth factor therapy (VEGF, n = 13) for metastatic RCC, a low CD105/CD31 ratio was associated with increased survival (P= .02). We conclude that higher neovascularity is associated with worse outcomes after surgery for RCC. The ratio of CD105/CD31 expression is a potential indicator of response to anti-VEGF therapy.

HIF-1α and HIF-2α induced angiogenesis in gastrointestinal vascular malformation and reversed by thalidomide

Thalidomide is used in clinical practice to treat gastrointestinal vascular malformation (GIVM), but the pathogenesis of GIVM is not clear. Hypoxia inducible factor 1 alpha (HIF-1α) and 2 alpha (HIF-2α/EPAS1) are in the same family and act as master regulators of the adaptive response to hypoxia. HIF-1α and HIF-2α are up-regulated in vascular malformations in intestinal tissues from GIVM patients, but not in adjacent normal vessels. Therefore, we investigated the role of HIF-1α and HIF-2α during angiogenesis and the mechanism of thalidomide action. In vitro experiments confirmed that vascular endothelial growth factor (VEGF) was a direct target of HIF-2α and that HIF-1α and HIF-2α regulated NOTCH1, Ang2, and DLL4, which enhanced vessel-forming of endothelial cells. Thalidomide down-regulated the expression of HIF-1α and HIF-2α and inhibited angiogenesis. In vivo zebrafish experiments suggested that HIF-2α overexpression was associated with abnormal subintestinal vascular (SIV) sprouting, which was reversed by thalidomide. This result indicated that thalidomide regulated angiogenesis via the inhibition of HIF-1α and HIF-2α expression, which further regulated downstream factors, including VEGF, NOTCH1, DLL4, and Ang2. The abnormally high expression of HIF-1α and HIF-2α may contribute to GIVM.

Hypoxia, Hypoxia-inducible Transcription Factors, and Renal Cancer

CONTEXT

Renal cancer is a common urologic malignancy, and therapeutic options for metastatic disease are limited. Most clear cell renal cell carcinomas (ccRCC) are associated with loss of von Hippel-Lindau tumor suppressor (pVHL) function and deregulation of hypoxia pathways.

OBJECTIVE

This review summarizes recent evidence from genetic and biological studies showing that hypoxia and hypoxia-related pathways play critical roles in the development and progress of renal cancer.

EVIDENCE ACQUISITION

We used a systematic search for articles using the keywords hypoxia, HIF, renal cancer, and VHL.

EVIDENCE SYNTHESIS

Identification of the tumor suppressor pVHL has allowed the characterization of important ccRCC-associated pathways. pVHL targets α-subunits of hypoxia-inducible transcription factors (HIF) for proteasomal degradation. The two main HIF-α isoforms have opposing effects on RCC biology, possibly through distinct interactions with additional oncogenes. Furthermore, HIF-1α activity is commonly diminished by chromosomal deletion in ccRCCs, and increased HIF-1 activity reduces tumor burden in xenograft tumor models. Conversely, polymorphisms at the HIF-2α gene locus predispose to the development of ccRCCs, and HIF-2α promotes tumor growth. Genetic studies have revealed a prominent role for chromatin-modifying enzyme genes in ccRCC, and these may further modulate specific aspects of the HIF response. This suggests that, rather than global activation of HIF, specific components of the response are important in promoting kidney cancer. Some of these processes are already targets for current therapeutic strategies, and further dissection of this pathway might yield novel methods of treating RCC.

CONCLUSIONS

In contrast to many tumor types, HIF-1α and HIF-2α have opposing effects in ccRCC biology, with HIF-1α acting as a tumor suppressor and HIF-2α acting as an oncogene. The overall effect of VHL inactivation will depend on fine-tuning of the HIF response.

PATIENT SUMMARY

High levels of hypoxia-inducible transcription factors (HIF) are particularly important in the clear cell type of kidney cancer, in which they are no longer properly regulated by the von Hippel-Lindau protein. The two HIF-α proteins have opposing effects on tumor evolution.

Tetramethylpyrazine inhibits tumor growth of lung cancer through disrupting angiogenesis via BMP/Smad/Id-1 signaling

The underlying mechanisms of inhibitory effects induced by tetramethylpyrazine (TMP) on angiogenesis and tumor growth of lung cancer were investigated. In vitro cell proliferation, migration, and tube formation of human microvascular endothelial cells (HMEC-1) were evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide (MTT), wound healing, Transwell, and Matrigel assays. The expression of BMP/Smad/Id-1 signals was detected by RT-PCR and western blotting. In an A549 xenograft tumor model, TMP (40 and 80 mg/kg/day) was intraperitoneally injected into mice. The expressions of CD31, phosphorylated Smad1/5/8, and Id-1 were measured by immunohistochemistry. We demonstrated that TMP inhibited proliferation, migration, and capillary tube formation of HMEC-1 in a dose- and time-dependent manner. Furthermore, treatment of HMEC-1 cells with TMP (0.4 mg/ml) significantly upregulated BMP2 expression and downregulated BMPRIA, BMPRII, phosphorylated Smad1/5/8, and Id-1 expression. In addition, administrations of TMP remarkably inhibited tumor growth of A549 xenograft in nude mice. The CD31, phosphorylated Smad1/5/8, and Id-1 expression were significantly inhibited in TMP-treated xenograft tumors compared with the vehicle. In conclusion, our results indicated that TMP suppressed angiogenesis and tumor growth of lung cancer via blocking the BMP/Smad/Id-1 signaling.

Combined Angiogenesis and Proliferation Markers' Expressions as Long-Term Prognostic Factors in Renal Cell Cancer

OBJECTIVES

The aim of this study was to evaluate the expression of MIB-1, BCL-2, VEGFR3, and CD31 and their associations with long-term survival in patients with renal cell cancer (RCC).

PATIENTS AND METHODS

This study consisted of 224 RCC patients who underwent radical nephrectomy from 1985 to 1995. Follow-up continued for up to over 20 years. MIB-1 and BCL-2 expression were analyzed alone, and additionally, the expression of MIB-1, BCL-2, VEGFR3, and CD31 were combined in pairs using the following groups: low/low, low/high, high/low, and high/high.

RESULTS

Low BCL-2 expression (hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.42-3.31; P < .001 compared with high BCL-2 in univariate analysis) and high MIB-1 expression (HR, 2.05; 95% CI, 1.32-3.19; P = .001 in multivariate analysis) were found to associate for poorer survival in RCC. In multivariate analysis, the combination of high MIB-1/low BCL-2 was associated with poor survival compared with low MIB-1/high BCL-2 (HR, 3.20; 95% CI, 1.66-6.17; P = .001), and the combination of low VEGFR3/high CD31 was associated with poor survival (HR, 2.48; 95% CI, 1.29-4.78; P = .007) compared with high VEGFR3/high CD31.

CONCLUSIONS

Compared with high BCL-2 expression in combination with low or high MIB-1, VEGFR3, or CD31 expression, low BCL-2 expression in combination with low or high MIB-1, VEGFR3, or CD31 expression has poorer survival in the long-term follow-up of patients with RCC. Analysis of MIB-1, BCL-2, VEGFR3, and CD31 expression might be a useful additional marker to tailor the follow-up of RCC patients.

Enhanced expression of CD31/platelet endothelial cell adhesion molecule 1 (PECAM1) correlates with hypoxia inducible factor-1 alpha (HIF-1α) in human glioblastoma multiforme

Glioblastoma multiforme (GBM) is characterized by numerous abnormal blood vessels, which rapidly proliferate and invade brain tissue and express different angiogenic factors. In this study we have investigated whether the expression levels of CD31/ PECAM1 are deregulated in human GBM tissue specimens and we have also correlated the expression levels of CD31/PECAM1 with those of HIF-1α. Finally, we have established a correlation between the expression levels of CD31/PECAM1 and HIF-1α, and those of two other biomarkers, namely N-cadherin and ADAM-10, of aggressiveness in the same tumors. Results have shown an increased expression of CD31/PECAM1 correlated to HIF-1α expression, confirming evidence demonstrating that different types of tumor are able to trigger aberrant angiogenesis through HIF-1α. Moreover, we also established a further correlation among CD31/PECAM1 and HIF-1α and N-cadherin and ADAM-10, two other markers of aggressiveness in the same tumors.

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.

PARVA promotes metastasis by modulating ILK signalling pathway in lung adenocarcinoma

α-parvin (PARVA) is known to be involved in the linkage of integrins, regulation of actin cytoskeleton dynamics and cell survival. However, the role that PARVA plays in cancer progression remains unclear. Here, using a lung cancer invasion cell line model and expression microarrays, we identify PARVA as a potential oncogene. The overexpression of PARVA increased cell invasion, colony-forming ability and endothelial cell tube formation. By contrast, knockdown of PARVA inhibited invasion and tube formation in vitro. Overexpression of PARVA also promoted tumorigenicity, angiogenesis and metastasis in in vivo mouse models. To explore the underlying mechanism, we compared the expression microarray profiles of PARVA-overexpressing cells with those of control cells to identify the PARVA-regulated signalling pathways. Pathway analysis showed that eight of the top 10 pathways are involved in invasion, angiogenesis and cell death. Next, to identify the direct downstream signalling pathway of PARVA, 371 significantly PARVA-altered genes were analysed further using a transcription factor target model. Seven of the top 10 PARVA-altered transcription factors shared a common upstream mediator, ILK. Lastly, we found that PARVA forms a complex with SGK1 and ILK to enhance the phosphorylation of ILK, which led to the phosphorylation of Akt and GSK3β. Notably, the inactivation of ILK reversed PARVA-induced invasion. Taken together, our findings imply that PARVA acts as an oncogene by activating ILK, and that this activation is followed by the activation of Akt and inhibition of GSK3β. To our knowledge, this is the first study to characterize the role of PARVA in lung cancer progression.

A novel long non-coding RNA, hypoxia-inducible factor-2α promoter upstream transcript, functions as an inhibitor of osteosarcoma stem cells in vitro

Long non-coding RNAs (lncRNAs) have recently been identified as novel modulators of malignant tumors. However, the function of lncRNAs in cancer stem cells (CSCs) remains to be elucidated. The present study aimed to investigate the regulating role of a novel lncRNA, hypoxia-inducible factor-2α (HIF-2α) promoter upstream transcript (HIF2PUT), in osteosarcoma stem cells. The expression levels of HIF2PUT were assessed by quantitative polymerase chain reaction in 17 osteosarcoma tissue specimens, and the correlation between the expression of HIF2PUT and its host transcript-HIF-2α was determined. In functional experiments, HIF2PUT expression was knocked down by small interfering RNAs, or overexpressed by transfection with pcDNA-HIF2PUT, in order to evaluate the effects of HIF2PUT on cell proliferation, migration, expression rate of osteosarcoma stem cell marker CD133, and stem sphere-forming ability in MG63 cells. HIF2PUT expression levels were positively correlated with HIF-2α in osteosarcoma tissues. Overexpression of HIF2PUT markedly inhibited cell proliferation and migration, decreased the percentage of CD133 expressing cells, and impaired the osteosarcoma stem sphere-forming ability of the MG63 cells. Whereas, knockdown of HIF2PUT expression had the opposite effect. Furthermore, altering the expression of HIF2PUT resulted in a concomitant change to HIF-2α mRNA expression. These results indicate that the lncRNA HIF2PUT may be a novel regulatory factor of osteosarcoma stem cells, which may exert its function partly by controlling HIF-2α expression. Further studies regarding HIF2PUT may provide a novel therapeutic target of osteosarcoma in the future.

Clinical and molecular prognostic and predictive biomarkers in clear cell renal cell cancer

ABSTRACT 

The natural history of clear cell renal cell cancer is highly unpredictable with various progressors and with populations where small renal masses may be accompanied by metastatic disease. Currently, there is a critical need to determine patient risk and optimize treatment regimes. For these patients, molecular markers may offer significant information in terms of prognostic and predictive values, as well as determination of valid therapeutic targets. Until now, only a few of the many identified clear cell renal cell cancer biomarkers have been clinically validated in large cohorts. And only several biomarkers are integrated in predictive or prognostic models. Therefore, a large cohesive effort is required to advance the field of clear cell renal cell cancer prognostic biomarkers through systematic discovery, verification, validation and clinical implementation.

Prognostic value of carbonic anhydrase IX immunohistochemical expression in renal cell carcinoma: a meta-analysis of the literature

Background

Carbonic anhydrase IX (CAIX) protein has been correlated with progression and survival in patients with renal cell carcinoma (RCC). The prognostic value of CAIX in RCC however, remains inconclusive according to published works. This study aimed to analyze CAIX as a biological marker to predict RCC patient prognosis.

Methods

A literature search of the PubMed and Web of Knowledge databases was performed to retrieve original studies from their inception to December of 2013. Fifteen studies, collectively including a total of 2611 patients with renal cell carcinoma, were carefully reviewed. Standard meta-analysis methods were applied to evaluate the prognostic impact of CAIX expression on patient prognosis. The hazard ratio (HR) and its 95% confidence interval (CI) were recorded for the relationship between CAIX expression and survival, and the data were analyzed using Review Manager 5.2 software and Stata software 11.0.

Results

In patients with RCC, low CAIX expression was associated with poor disease-specific survival (HR = 1.89, 95% CI: 1.20–2.98, P = 0.006), unfavorable progression-free survival (HR = 2.62, 95% CI: 1.14–6.05, P = 0.02) and worse overall survival (HR = 2.03, 95% CI: 1.28–3.21, P = 0.002). Furthermore, low CAIX expression was significantly associated with the presence of lymph node metastases (odds ratio (OR) = 0.31, 95% CI = 0.15–0.62, P = 0.0009) and distant metastases (OR = 0.66, 95% CI = 0.46–0.96, P = 0.03) and predicted a higher tumor grade (OR = 0.41, 95% CI = 0.31–0.54, P<0.00001).

Conclusions

Low CAIX expression most likely indicates poor prognosis in RCC patients. Moreover, low CAIX expression was significantly associated with unfavorable clinicopathological factors. To strengthen our findings, further well-designed prospective studies should be conducted to investigate the role of CAIX expression in RCC.

The role of HIF1α in renal cell carcinoma tumorigenesis

The transcription factor HIF1α is implicated in the development of clear cell renal cell carcinoma (ccRCC). Although HIF1α was initially believed to be essential for ccRCC development, recent studies hypothesize an oncogenic role for HIF2α in ccRCC, but a tumor suppressor role for HIF1α, leading to uncertainty as to the precise roles of the different HIF transcription factors in this disease. Using evidence available from studies with human ccRCC cell lines, mouse xenografts, murine models of ccRCC, and human ccRCC specimens, we evaluate the roles of HIF1α and HIF2α in the pathogenesis of ccRCC. We present a convergence of clinical and mechanistic data supporting an important role for HIF1α in promoting tumorigenesis in a clinically important and large subset of ccRCC. This indicates that current understanding of the exact roles of HIF1α and HIF2α is incomplete and that further research is required to determine the diverse roles of HIF1α and HIF2α in ccRCC.

KEY MESSAGES

The TRACK mouse ccRCC model with constitutively active HIF1α but not HIF2α expressed in proximal tubules develops RCC. HIF1α protein is expressed in the majority of human ccRCC specimens. Elevated HIF1α in ccRCC correlates with a worse prognosis. Many publications do not support a tumor suppressor role for HIF1α in ccRCC. HIF1α, but not HIF2α, is expressed in some types of cancer stem cells.

Analysis and validation of tissue biomarkers for renal cell carcinoma using automated high-throughput evaluation of protein expression

The objective of this study was to compare the predictive ability of potential tissue biomarkers to known prognostic factors that predict renal cell carcinoma (RCC) recurrence using an automated system of immunohistochemical analysis. After institutional review board approval, a tissue microarray was constructed using tissue from patients who had partial or radical nephrectomy for RCC. Patients with metastatic disease were excluded. Immunohistochemical staining of the tissue microarray for Ki-67, C-reactive protein, carbonic anhydrase 9, and hypoxia-inducible factors 1α and 2α was analyzed using automated image analysis. Univariable and multivariable analyses were performed to evaluate the association of putative biomarkers and known prognostic factors. Of 216 patients who met the entrance criteria, 34 (16%) patients developed metastatic recurrence within a median follow-up interval of 60.9 (interquartile range, 13.9-87.1) months. RCC morphotypes analyzed in this study include clear cell (n = 156), papillary (n = 38), chromophobe (n = 16), and collecting duct/unclassified (n = 6). Univariate analysis identified that only increased Ki-67 was predictive of RCC recurrence among the proteins evaluated, in addition to other known clinicopathological prognostic factors. After multivariate analysis, Ki-67 was identified as an independently predictive risk factor for RCC recurrence (hazard ratio [HR], 3.73 [confidence interval {CI}, 1.60-8.68]). Other independent predictors of RCC recurrence included tumor diameter (HR, 1.20 [CI, 1.02-1.41]) and perinephric fat invasion (HR, 4.49 [CI, 1.11-18.20]). We conclude that Ki-67 positivity is independently predictive of RCC recurrence after surgery in nonmetastatic patients. Automated analysis of tissue protein expression can facilitate a more objective and expedient investigation of tissue biomarkers for RCC.

Emerging strategies to overcome the resistance to current mTOR inhibitors in renal cell carcinoma

The mammalian target of rapamycin (mTOR) has emerged as an attractive cancer therapeutic target. Treatment of metastatic renal cell carcinoma (mRCC) has improved significantly with the advent of agents targeting the mTOR pathway, such as temsirolimus and everolimus. Unfortunately, a number of potential mechanisms that may lead to resistance to mTOR inhibitors have been proposed. In this paper, we discuss the mechanisms underlying resistance to mTOR inhibitors, which include the downstream effectors of the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway, the activation of hypoxia-inducible factor (HIF), the PIM kinase family, PTEN expression, elevated superoxide levels, stimulation of autophagy, immune cell response and ERK/MAPK, Notch and Aurora signaling pathways. Moreover, we present an updated analysis of clinical trials available on PubMed Central and www.clinicaltrials.gov, which were pertinent to the resistance to rapalogs. The new frontier of inhibiting the mTOR pathway is to identify agents targeting the feedback loops and cross talks with other pathways involved in the acquired resistance to mTOR inhibitors. The true goal will be to identify biomarkers predictive of sensitivity or resistance to efficiently develop novel agents with the aim to avoid toxicities and to better choose the active drug for the right patient.

Analyses of potential predictive markers and survival data for a response to sunitinib in patients with metastatic renal cell carcinoma

BACKGROUND

Patients with metastatic clear cell renal cell carcinoma (ccRCC) are frequently treated with tyrosine kinase inhibitors (TKI) such as sunitinib. It inhibits angiogenic pathways by mainly targeting the receptors of VEGF and PDGF. In ccRCC, angiogenesis is characterized by the inactivation of the von Hippel-Lindau gene (VHL) which in turn leads to the induction of HIF1α target genes such as CA9 and VEGF. Furthermore, the angiogenic phenotype of ccRCC is also reflected by endothelial markers (CD31, CD34) or other tumor-promoting factors like Ki67 or survivin.

METHODS

Tissue microarrays from primary tumor specimens of 42 patients with metastatic ccRCC under sunitinib therapy were immunohistochemically stained for selected markers related to angiogenesis. The prognostic and predictive potential of theses markers was assessed on the basis of the objective response rate which was evaluated according to the RECIST criteria after 3, 6, 9 months and after last report (12-54 months) of sunitinib treatment. Additionally, VHL copy number and mutation analyses were performed on DNA from cryo-preserved tumor tissues of 20 ccRCC patients.

RESULTS

Immunostaining of HIF-1α, CA9, Ki67, CD31, pVEGFR1, VEGFR1 and -2, pPDGFRα and -β was significantly associated with the sunitinib response after 6 and 9 months as well as last report under therapy. Furthermore, HIF-1α, CA9, CD34, VEGFR1 and -3 and PDGRFα showed significant associations with progression-free survival (PFS) and overall survival (OS). In multivariate Cox proportional hazards regression analyses high CA9 membrane staining and a response after 9 months were independent prognostic factors for longer OS. Frequently observed copy number loss and mutation of VHL gene lead to altered expression of VHL, HIF-1α, CA9, and VEGF.

CONCLUSIONS

Immunoexpression of HIF-1α, CA9, Ki67, CD31, pVEGFR1, VEGFR1 and -2, pPDGFRα and -β in the primary tumors of metastatic ccRCC patients might support the prediction of a good response to sunitinib treatment.

Sperm-associated antigen 4, a novel hypoxia-inducible factor 1 target, regulates cytokinesis, and its expression correlates with the prognosis of renal cell carcinoma

Hypoxia plays a crucial role in many pathophysiological conditions, including cancer biology, and hypoxia-inducible factor (HIF) regulates transcriptional responses under hypoxia. To elucidate the cellular responses to hypoxia, we performed chromatin immunoprecipitation with deep sequencing in combination with microarray analysis and identified HIF-1 targets. We focused on one of the novel targets, sperm-associated antigen 4 (SPAG4), whose function was unknown. SPAG4, an HIF-1-specific target, is up-regulated in various cultured cells under hypoxia. Examination of SPAG4 expression using a tissue microarray consisting of 190 human renal cell carcinoma (RCC) samples revealed that SPAG4 is an independent prognostic factor of cancer-specific mortality. Live-cell imaging revealed localization of SPAG4 at the intercellular bridge in telophase. We also studied cells in which SPAG4 was knocked down. Hypoxia enhances tetraploidy, which disturbs cell proliferation, and knockdown of SPAG4 increased tetraploid formation and decreased cell proliferation under both normoxic and hypoxic conditions. Studies using deletion mutants of SPAG4 also suggested the involvement of SPAG4 in cytokinesis. Microarray analysis confirmed dysregulation of cytokinesis-related genes by knockdown of SPAG4. In conclusion, SPAG4 is an independent prognostic factor in RCC and plays a crucial role in cytokinesis to defend against hypoxia-induced tetraploid formation. This defensive mechanism may promote survival of cancer cells under hypoxic conditions, thus leading to poor prognosis.

Activation of HIF2α in kidney proximal tubule cells causes abnormal glycogen deposition but not tumorigenesis

Renal cell carcinoma (RCC) is the most common primary cancer arising from the kidney in adults, with clear cell renal cell carcinoma (ccRCC) representing approximately 75% of all RCCs. Increased expression of the hypoxia-induced factors-1α (HIF1α) and HIF2α has been suggested as a pivotal step in ccRCC carcinogenesis, but this has not been thoroughly tested. Here, we report that expression of a constitutively activated form of HIF2α (P405A, P530A, and N851A, named as HIF2αM3) in the proximal tubules of mice is not sufficient to promote ccRCC by itself, nor does it enhance HIF1αM3 oncogenesis when coexpressed with constitutively active HIF1αM3. Neoplastic transformation in kidneys was not detected at up to 33 months of age, nor was increased expression of Ki67 (MKI67), γH2AX (H2AFX), or CD70 observed. Furthermore, the genome-wide transcriptome of the transgenic kidneys does not resemble human ccRCC. We conclude that a constitutively active HIF2α is not sufficient to cause neoplastic transformation of proximal tubules, arguing against the idea that HIF2α activation is critical for ccRCC tumorigenesis.

Metabolism of kidney cancer: from the lab to clinical practice

CONTEXT

There is increasing evidence for the role of altered metabolism in the pathogenesis of renal cancer.

OBJECTIVE

This review characterizes the metabolic effects of genes and signaling pathways commonly implicated in renal cancer.

EVIDENCE ACQUISITION

A systematic review of the literature was performed using PubMed. The search strategy included the following terms: renal cancer, metabolism, HIF, VHL.

EVIDENCE SYNTHESIS

Significant progress has been made in the understanding of the metabolic derangements present in renal cancer. These findings have been derived through translational, in vitro, and in vivo studies. To date, the most well-characterized metabolic features of renal cancer are linked to von Hippel-Lindau (VHL) loss. VHL loss and the ensuing increase in the expression of hypoxia-inducible factor affect several metabolic pathways, including glycolysis and oxidative phosphorylation. Collectively, these changes promote a glycolytic metabolic phenotype in renal cancer. In addition, other histologic subtypes of renal cancer are also notable for metabolic derangements that are directly related to the causative genes.

CONCLUSIONS

Current knowledge of the genetics of renal cancer has led to significant understanding of the metabolism of this malignancy. Further studies of the metabolic basis of renal cell carcinoma should provide the foundation for the development of new treatment approaches and development of novel biomarkers.