Nuclear expression of hypoxia-inducible factor-1alpha in clear cell renal cell carcinoma is involved in tumor progression

LINC00365 as a potential biomarker for total nephrectomy in advanced-stage renal cell carcinoma patients

BACKGROUND

Renal cell carcinoma (RCC) is one of the most frequent urological cancers globally that has a good prognosis in the early tumor stages. However, there is a poor prognosis in metastatic RCC patients. Therefore, it is needed to evaluate the molecular biology of RCC progression to introduce the efficient diagnostic and therapeutic markers in these patients. Long non-coding RNAs (lncRNAs) have key roles in regulation of molecular mechanisms during RCC progression. In the present study, we assessed the levels of LINC00365 expressions in RCC patients to suggest that as a tumor marker in these patients.

METHODS

Fifty fresh RCC tumor tissues and their normal margins were collected to assess the levels of LINC00365 expressions and probable correlations with clinicopathological features of RCC patients.

RESULTS

There was significant LINC00365 up regulation in females compared with males (p=0.050). Among the RCC patients with total nephrectomy, there was a significant LINC00365 up regulation in advanced stage compared with primary stage tumors (p=0.035). RCC patients older than 60 years old who were undergone the total nephrectomy had also significant LINC00365 up regulation compared with RCC patients younger than 60 years old (p=0.039).

CONCLUSIONS

given the significant increase in LINC00365 expression in advanced stage RCC tumors and patients over 60 years old who had total nephrectomy; it could serve as a useful diagnostic marker in screening programs for old high-risk individuals. It was also noticed that female RCC patients had elevated levels of LINC00365 expressions in their tumor samples, suggesting its potential use as a gender-specific diagnostic marker for high-risk females. Nevertheless, evaluating the levels of LINC00365 in serum samples of RCC patients is necessary to suggest that as a reliable diagnostic marker in clinical settings.

Targeting hypoxia-inducible factor pathways in sporadic and Von Hippel-Lindau syndrome-related kidney cancers

Hereditary and sporadic renal cell carcinomas (RCCs) are often associated with Von Hippel-Lindau (VHL)-gene inactivation. Patients with VHL disease have an increased risk of RCC, leading to bilateral nephrectomy and dialysis. In patients with advanced RCC, no standard second-lines are available after progression to immune checkpoint inhibitors (ICIs), and new agents are required to manage progression. HIFs have emerged as a promising target for metastatic RCC patients who have progressed to ICI-based combinations, as well as for those with RCC and VHL syndrome where the goal is to delay surgery and/or and preserve kidney function and avoid dialysis. This review describes the available evidence supporting the use of the small-molecule HIF-2 alpha inhibitor, belzutifan (MK-6482), as well as other new anti-HIF molecules that have demonstrated significant efficacy in VHL disease-related RCCs as well as for sporadic RCC that has progressed after the use of ICI-based combinations.

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.

Hypoxia Inducible Factor-1alpha (HIF-1A) plays different roles in Gallbladder Cancer and Normal Gallbladder Tissues

Purpose: Hypoxia-inducible factor-1alpha (HIF-1A) is a transcription factor that plays an “angiogenic switch” role especially under hypoxia microenvironment in solid tumor. However, the functions and clinical significance of HIF-1A in gallbladder cancer (GBC) are still controversial, and it has not been studied in normal gallbladder tissues. In this study, we sought to clarify the role of sub-cellular localization of HIF-1A expression in GBC and normal gallbladder tissues.

Methods: The expressions of HIF-1A and CD34 in 127 GBC and 47 normal gallbladder tissues were evaluated by immunohistochemistry. Cox's proportional hazards model analysis and Kaplan-Meier method analysis were used to assess the correlations between these factors and clinicopathological features and prognosis.

Results: HIF-1A was expressed in both cytoplasm and nucleus of GBC and normal control tissues, and was significantly correlated with microvessel density (MVD). GBC tissues with positive nuclear HIF-1A expression had higher MVD compared to that with positive cytoplasmic HIF-1A expression; however, in normal gallbladder tissues, samples with positive cytoplasmic HIF-1A had higher MVD compared to that with positive nuclear HIF-1A expression. Moreover, GBC with nuclear HIF-1A expression tended to be more poorly differentiated and had larger tumor size compared to that with cytoplasm HIF-1A expression. Furthermore, GBC patients with nuclear HIF-1A positive were significantly correlated with worse overall survival (OS) compared with cytoplasmic HIF-1A positive. Multivariate Cox regression analysis identified lymph node metastasis and nuclear HIF-1A expression to be independent prognostic parameter in GBC.

Conclusions: Our findings provide evidence for the first time that HIF-1A is expressed in normal gallbladder tissues. Nuclear HIF-1A and cytoplasm HIF-1A plays different roles in GBC and normal gallbladder tissues.

HIF1α is not a target of 14q deletion in clear cell renal cancer

HIF1α has been termed a tumor-suppressor in clear cell renal cell carcinoma (ccRCC), primarily based on functional proliferation studies in cell lines (in vitro and in vivo) with genetic manipulation, and the adverse prognosis of 14q-deleted ccRCC patients. In other malignancies, however, HIF1α has an established tumor-promoting role. Therefore, this study sought to further examine the role of HIF1α in ccRCC using bioinformatic analyses of 530 ccRCC patients from The Cancer Genome Atlas (TCGA) and The Cancer Proteome Atlas (TCPA) registries. Although lower copy numbers of HIF1A (encoding HIF1α, located at 14q23.2) was associated with worse survival, there was no survival difference based on either HIF1A mRNA or HIF1α protein expression. Interestingly, L2HGDH (L-2-Hydroxyglutarate Dehydrogenase), a recently characterized epigenetic modulating ccRCC tumor-suppressor with a marked impact on survival, was found to be located only ~ 11.5Mbp from HIF1A on 14q (at 14q21.3). L2HGDH was therefore co-deleted in ~ 95% of 14q deletions involving HIF1A locus. Remarkably, HIF1A CNV had a markedly stronger correlation with L2HGDH expression (Rho = 0.55) than its own gene expression (Rho = 0.27), indicating high preserved-allele compensation of HIF1A. Genetic loss of HIF1A was therefore associated with a much greater reduction of L2HGDH gene expression than its own gene expression, providing a possible explanation for survival differences based on HIF1A CNV and mRNA expression. Furthermore, in 14q-deleted ccRCC patients with complete (uncensored) survival data, in the relatively rare cases where genetic loss of HIF1A occurred without genetic loss of L2HGDH (n = 5), the survival was significantly greater than where there was simultaneous genetic loss of both (n = 87) (mean survival 1670.8 ± 183.5 days vs 885.1 ± 78.4 days; p = 0.007). In addition, there was no correlation between HIF1A mRNA and HIF1α protein expression in ccRCC (R = 0.02), reflecting the primarily post-translational regulation of HIF1α. Lastly, even between L2HGDH and HIF1A loci, 14q was found to have several other yet-to-be-characterized potential ccRCC tumor-suppressors. Taken together, the data indicate that HIF1α is not a target of 14q deletion in ccRCC and that it is not a tumor-suppressor in this malignancy.

Circular RNAs in renal cell carcinoma: implications for tumorigenesis, diagnosis, and therapy

Renal cell carcinoma (RCC) is the most common malignant kidney tumor and has a high incidence rate. Circular RNAs (circRNAs) are noncoding RNAs with widespread distribution and diverse cellular functions. They are highly stable and have organ- and tissue-specific expression patterns. CircRNAs have essential functions as microRNA sponges, RNA-binding protein- and transcriptional regulators, and protein translation templates. Recent reports have shown that circRNAs are abnormally expressed in RCC and act as important regulators of RCC carcinogenesis and progression. Moreover, circRNAs have emerged as potential biomarkers for RCC diagnosis and prognosis and targets for developing new treatments. However, further studies are needed to better understand the functions of circRNAs in RCC. In this review, we summarize and discuss the recent research progress on RCC-associated circRNAs, with a focus on their potential for RCC diagnosis and targeted therapy.

Exosomal circular RNA_400068 promotes the development of renal cell carcinoma via the miR‑210‑5p/SOCS1 axis

Renal cell carcinoma (RCC) is a common type of malignancy in the kidney, which accounts for ~80% of the cases within adult patients. The pathogenesis of RCC is complicated and involves alterations at both genetic and epigenetic levels. The aim of the present study was to investigate the roles of circRNAs in the pathogenesis of RCC. In the current study, exosomes were isolated via gradient centrifugation and identified using transmission electron microscope. The expression levels of circular RNA (circ)_400068, microRNA (miR)‑210‑5p and suppressor of cytokine signaling 1 (SOCS1) were examined using reverse transcription‑quantitative PCR. Cell proliferation was evaluated using a Cell Counting Kit‑8 assay, and the apoptotic rate was determined in transfected cells using flow cytometry. The protein expression levels of proliferation‑ and apoptosis‑associated genes were assessed via western blot analysis. Upregulation of circ_400068 was detected in RCC plasma exosomes, tissue samples and cells. Additionally, treatment with exosomal circ_400068 promoted the proliferation and inhibited the apoptosis of healthy kidney cells, which were abrogated by short hairpin RNA‑circ_400068. The results suggested that miR‑210‑5p was a potential downstream molecule of circ_400068, and SOCS1 was a novel target of miR‑210‑5p. Moreover, circ_400068 regulated the proliferation of HK‑2 cells by targeting the miR‑210‑5p/SOCS1 axis, as the effects on cell proliferation caused by treatment using exosomes isolated from the culture media of RCC cells were abolished by miR‑210‑5p mimics. It was found that enhanced cell proliferation induced by miR‑210‑5p inhibitors was attenuated by the knockdown of SOCS1, while the influences triggered by miR‑210‑5p mimics were reversed by SOCS1 overexpression. Collectively, the present findings provided a novel insight into the crucial regulatory functions of circ_400068 in RCC, and the circ_400068/miR‑210‑5p/SOCS1 axis could be a candidate therapeutic target for the treatment of patients with RCC.

Targeting β2-Adrenergic Receptors Shows Therapeutical Benefits in Clear Cell Renal Cell Carcinoma from Von Hippel-Lindau Disease

Von Hippel–Lindau (VHL), is a rare autosomal dominant inherited cancer in which the lack of VHL protein triggers the development of multisystemic tumors such us retinal hemangioblastomas (HB), CNS-HB, and clear cell renal cell carcinoma (ccRCC). ccRCC ranks third in terms of incidence and first in cause of death. Standard systemic therapies for VHL-ccRCC have shown limited response, with recurrent surgeries being the only effective treatment. Targeting of β2-adrenergic receptor (ADRB) has shown therapeutic antitumor benefits on VHL-retinal HB (clinical trial) and VHL-CNS HB (in vitro). Therefore, the in vitro and in vivo antitumor benefits of propranolol (ADRB-1,2 antagonist) and ICI-118,551 (ADRB-2 antagonist) on VHL^−/− ccRCC primary cultures and 786-O tumor cell lines have been addressed. Propranolol and ICI-118,551 activated apoptosis inhibited gene and protein expression of HIF-2α, CAIX, and VEGF, and impaired partially the nuclear internalization of HIF-2α and NFĸB/p65. Moreover, propranolol and ICI-118,551 reduced tumor growth on two in vivo xenografts. Finally, ccRCC patients receiving propranolol as off-label treatment have shown a positive therapeutic response for two years on average. In summary, propranolol and ICI-118,551 have shown antitumor benefits in VHL-derived ccRCC, and since ccRCCs comprise 63% of the total RCCs, targeting ADRB2 becomes a promising drug for VHL and other non-VHL tumors.

lncRNA ROR promotes the progression of renal cell carcinoma through the miR‑206/VEGF axis

Renal cell carcinoma (RCC) is the most common kidney malignancy, responsible for ~80% of all cases in adults. The pathogenesis of RCC is complex, involving alterations at both the genetic and epigenetic levels. Numerous signaling pathways, such as PI3K/Akt/mTOR and Wnt‑β‑catenin have been demonstrated to be associated with the tumorigenesis and development of RCC. Long non‑coding RNAs (lncRNAs) are functional RNA molecules involved in the initiation and progression of cancer, and investigating the effects of lncRNA could facilitate the development of novel treatments. The lncRNA regulator of reprogramming (ROR) is aberrantly expressed in a variety of tumors. However, its underlying mechanisms remain largely unknown. In the present study, ROR was found to be upregulated and microRNA (miR)‑206 was found to be downregulated in RCC tissues and cells. Furthermore, the knockdown of ROR inhibited the proliferation, migration and invasion of RCC cells. It was found that ROR binds to miR‑206, and that ROR‑induced cell proliferation and metastasis were reversed by the overexpression of miR‑206. In addition, the levels of miR‑206 and ROR were negatively correlated in RCC tissues. Furthermore, the overexpression of miR‑206 notably suppressed the proliferation, migration and invasion of RCC cells, and these effects were enhanced by the knockdown of vascular endothelial growth factor (VEGF); cell growth and metastasis induced by miR‑206 inhibitors could be reversed by the knockdown of VEGF. In addition, the expression levels of miR‑206 and VEGF were inversely correlated in RCC samples. In summary, the results of the present study revealed that ROR was upregulated in RCC tissues, which promoted tumor progression by regulating the miR‑206/VEGF axis. The present findings provided a novel insight into the potential functions of ROR in RCC, and the ROR/miR‑206/VEGF pathway may be a promising therapeutic target for the treatment of patients with RCC.

Long non-coding RNAs in renal cell carcinoma: A systematic review and clinical implications

Renal cell carcinoma is one of the most common malignancy in adults, its prognosis is poor in an advanced stage and early detection is difficult due to the lack of molecular biomarkers. The identification of novel biomarkers for RCC is an urgent and meaningful project. Long non-coding RNA (lncRNA) is transcribed from genomic regions with a minimum length of 200 bases and limited protein-coding potential. Recently, lncRNAs have been greatly studied in a variety of cancer types. They participate in a wide variety of biological processes including cancer biology. In this review, we provide a new insight of the profiling of lncRNAs in RCC and their roles in renal carcinogenesis, with an emphasize on their potential in diagnosis, prognosis and potential roles in RCC therapy.

Opposite prognostic roles of HIF1α and HIF2α expressions in bone metastatic clear cell renal cell cancer

BACKGROUND

Prognostic markers of bone metastatic clear cell renal cell cancer (ccRCC) are poorly established. We tested prognostic value of HIF1α/HIF2α and their selected target genes in primary tumors and corresponding bone metastases.

RESULTS

Expression of HIF2α was lower in mRCC both at mRNA and protein levels (p/mRNA/=0.011, p/protein/=0.001) while HIF1α was similar to nmRCC. At the protein level, CAIX, GAPDH and GLUT1 were increased in mRCC. In all primary RCCs, low HIF2α and high HIF1α as well as CAIX, GAPDH and GLUT1 expressions correlated with adverse prognosis, while VEGFR2 and EPOR gene expressions were associated with favorable prognosis. Multivariate analysis confirmed high HIF2α protein expression as an independent risk factor. Prognostic validation of HIFs, LDH, EPOR and VEGFR2 in RNA-Seq data confirmed higher HIF1α gene expression in primary RCC as an adverse (p=0.07), whereas higher HIF2α and VEGFR2 expressions as favorable prognostic factors. HIF1α/HIF2α-index (HIF-index) proved to be an independent prognostic factor in both the discovery and the TCGA cohort.

PATIENTS AND METHODS

Expressions of HIF1α and HIF2α as well as their 7 target genes were analysed on the mRNA and protein level in 59 non-metastatic ccRCCs (nmRCC), 40 bone metastatic primary ccRCCs (mRCC) and 55 corresponding bone metastases. Results were validated in 399 ccRCCs from the TCGA project.

CONCLUSIONS

We identified HIF2α protein as an independent marker of the metastatic potential of ccRCC, however, unlike HIF1α, increased HIF2α expression is a favorable prognostic factor. The HIF-index incorporated these two markers into a strong prognostic biomarker of ccRCC.

Evaluation of Hypoxia Inducible Factor-1α and Glucose Transporter-1 Expression in Non Melanoma Skin Cancer: An Immunohistochemical Study

INTRODUCTION

Hypoxia Inducible Factor-1 (HIF-1) is a mediator enabling cell adaptation to hypoxia. It plays its role mainly through transcription of many target genes including Glucose Transporter-1 (GLUT-1) gene.

AIM

The present work aimed at evaluating the pattern and distribution of HIF-1α and GLUT-1 in each case and control.

MATERIALS AND METHODS

A case-control and retrospective study was conducted on archival blocks diagnosed from pathology department as, Basal Cell Carcinoma (BCC, 20 cases), cutaneous Squamous Cell Carcinoma (SCC, 20 cases) and 20 normal site-matched skin biopsies from age and gender-matched healthy subjects as a control. Evaluation of both HIF-1α and GLUT1 expression using standard immunohistochemical techniques was performed on cut sections from selected paraffin embedded blocks.

RESULTS

HIF-1α was expressed in 90%, 35% and 100% of normal skin, BCC and SCC tumour islands respectively. It was up regulated in both BCC and SCC compared with normal skin (p= 0.001, p<0.001 respectively). GLUT-1 was expressed in 100%, 70% and 100% of normal skin, BCC and SCC tumour islands respectively. It was down regulated in Non Melanoma Skin Cancer (NMSC) cases compared with normal skin (p=0.004). HIF-1α and GLUT-1 localization in tumour nests was central, peripheral or central and peripheral. Both HIF-1α and GLUT-1 showed variable expression in stroma, adnexa and inflammatory cells. No significant correlation was found between Histo (H) score or expression percentage values of HIF-1α and those of GLUT-1 in tumour islands or in overlying epidermis either in BCC or SCC.

CONCLUSION

HIF-1α may have a role in NMSC pathogenesis through adaptation to hypoxia which results from excessive proliferation. GLUT-1 down regulation in NMSC may be explained by its consumption by proliferating tumour cells. The expression of HIF-1α and GLUT-1 in normal epidermis, stromal and adnexal structures needs further research.

Expression of von Hippel-Lindau tumor suppressor protein (pVHL) characteristic of tongue cancer and proliferative lesions in tongue epithelium

Background

Patients with tongue cancer frequently show loss of heterozygosity (LOH) of the von Hippel–Lindau (VHL) tumor suppressor gene. However, expression of VHL protein (pVHL) in tongue cancer has rarely been investigated and remains largely unknown. We performed immunohistochemical staining of pVHL in tongue tissues and dysplasia, and examined the association with LOH and its clinical significance.

Methods

Immunohistochemical staining of pVHL in formalin-fixed, paraffin-embedded sections of cancerous and other tissues from 19 tongue cancer patients showed positivity for LOH of VHL in four samples, negativity in four samples, and was non-informative in 11 samples. The staining pattern of pVHL was also compared with those of cytokeratin (CK) 13 and CK17.

Results

In normal tongue tissues, pVHL staining was localized to the cytoplasm of cells in the basal layer and the area of the spinous layer adjacent to the basal layer of stratified squamous epithelium. Positive staining for pVHL was observed in the cytoplasm of cancer cells from all 19 tongue cancer patients. No differences as a result of the presence or absence of LOH were found. Notably, cytoplasm of poorly differentiated invasive cancer cells was less intensely stained than that of well and moderately differentiated invasive cancer cells. pVHL staining was also evident in epithelial dysplasia lesions with pVHL-positive cells expanding from the basal layer to the middle of the spinous layer. However, no CK13 staining was noted in regions of the epithelium, which were positive for pVHL. In contrast, regions with positive staining for CK17 closely coincided with those positive for pVHL.

Conclusions

Positive staining for pVHL was observed in cancerous areas but not in normal tissues. pVHL expression was also detected in lesions of epithelial dysplasia. These findings suggest that pVHL may be a useful marker for proliferative lesions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3364-8) contains supplementary material, which is available to authorized users.

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.

Role of Ran-regulated nuclear-cytoplasmic trafficking of pVHL in the regulation of microtubular stability-mediated HIF-1α in hypoxic cardiomyocytes

Our previous study suggested that microtubule network alteration affects the process of glycolysis in cardiomyocytes (CMs) via the regulation of hypoxia-inducible factor (HIF)-1α during the early stages of hypoxia. However, little is known regarding the underlying mechanisms of microtubule network alteration-induced changes of HIF-1α. The von Hippel–Lindau tumor suppressor protein (pVHL) has been shown to mediate the ubiquitination of HIF-1α in the nuclear compartment prior to HIF-1α exportation to the cytoplasm, and pVHL dynamic nuclear-cytoplasmic trafficking is indicated to be involved in the process of HIF-1α degradation. In this study, by administering different microtubule-stabilizing and -depolymerizing interventions, we demonstrated that microtubule stabilization promoted pVHL nuclear export and drove the translocation of pVHL to the cytoplasm, while microtubule disruption prevented pVHL nuclear export in hypoxic CMs. Moreover, the ratio between nuclear and cytoplasmic pVHL was associated with HIF-1α regulation. Importantly, microtubule network alteration also affected the subcellular localization of Ran, which was involved in the regulation of pVHL nuclear-cytoplasmic trafficking. The above results suggest that the subcellular translocation of pVHL plays an important role in microtubular structure alteration-induced HIF-1α regulation. Interestingly, Ran is involved in the process of pVHL nuclear-cytoplasmic trafficking following microtubule network alteration in hypoxic CMs.

Pre-clinical evaluation of AZD-2014, a novel mTORC1/2 dual inhibitor, against renal cell carcinoma

Here we found that dual mTORC1/2 inhibitor AZD-2014 significantly inhibited RCC cell survival and growth, with higher efficiency than conventional mTORC1 inhibitors rapamycin and RAD001. RCC cell apoptosis was also induced by AZD-2014. AZD-2014 disrupted mTORC1/2 assembly and activation, while downregulating HIF-1α/2α and cyclin D1 expressions in RCC cells. Meanwhile, AZD-2014 activated autophagy, detected by p62 degradation, Beclin-1/ATG-5 upregulation and light LC3B-I/-II conversion. Autophagy inhibition by pharmacologic or siRNA-based means increased AZD-2014 activity in vitro, causing substantial RCC cell apoptosis. In vivo, AZD-2014 was more efficient than RAD001 in inhibiting 786-0 xenografts and downregulating HIF-1α/2α or p-AKT (Ser-473). Finally, AZD-2014's activity in vivo was further enhanced by co-administration of the autophagy inhibitor 3-methyaldenine. We provide evidence for clinical trials of using AZD-2014 in RCC treatment.

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.

Stage-dependent prognostic impact of molecular signatures in clear cell renal cell carcinoma

Purpose

To enhance prognostic information of protein biomarkers for clear cell renal cell carcinomas (ccRCCs), we analyzed them within prognostic groups of ccRCC harboring different tumor characteristics of this clinically and molecularly heterogeneous tumor entity.

Methods

Tissue microarrays from 145 patients with primary ccRCC were immunohistochemically analyzed for VHL (von Hippel-Lindau tumor suppressor), Ki67 (marker of proliferation 1), p53 (tumor protein p53), p21 (cyclin-dependent kinase inhibitor 1A), survivin (baculoviral IAP repeat containing 5), and UEA-1 (Ulex europaeus agglutinin I) to assess microvessel-density.

Results

When analyzing all patients, nuclear staining of Ki67 (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.04–1.12) and nuclear survivin (nS; HR 1.04, 95% CI 1.01–1.08) were significantly associated with disease-specific survival (DSS). In the cohort of patients with advanced localized or metastasized ccRCC, high staining of Ki67, p53 and nS predicted shorter DSS (Ki67: HR 1.07, 95% CI 1.02–1.11; p53: HR 1.05, 95% CI 1.01–1.09; nS: HR 1.08, 95% CI 1.02–1.14). In organ-confined ccRCC, patients with high p21-staining had a longer DSS (HR 0.96, 95% CI 0.92–0.99). In a multivariate model with stepwise backward elimination, tumor size and p21-staining showed a significant association with DSS in patients with “organ-confined” ccRCCs. The p21-staining increased the concordance index of tumor size from 0.75 to 0.78. In patients with “organ-confined” ccRCC, no disease-related deaths occurred in the group with p21-expression below the threshold of 32.5% p21-positive cells (log rank test: P=0.002).

Conclusion

The prognostic information of the studied protein biomarkers depended on anatomic tumor stages, which displayed different acquired biological tumor characteristics. Analysis of prognostic factors within different clinical ccRCC groups could help to enhance their prognostic power. The p21-staining was an independent prognostic factor and increased prognostic accuracy in a predictive model in “organ-confined” ccRCC.

VHL and HIF-1α: gene variations and prognosis in early-stage clear cell renal cell carcinoma

Von Hipple-Lindau gene (VHL) inactivation represents the most frequent abnormality in clear cell renal cell carcinoma (ccRCC). Hypoxia-inducible factor-1α (HIF-1α) expression is regulated by O2 level. In normal O2 conditions, VHL binds HIF-1α and allows HIF-1α proteasomal degradation. A single-nucleotide polymorphism (SNP) has been found located in the oxygen-dependent degradation domain at codon 582 (C1772T, rs11549465, Pro582Ser). In hypoxia, VHL/HIF-1α interaction is abolished and HIF-1α activates target genes in the nucleus. This study analyzes the impact of genetic alterations and protein expression of VHL and the C1772T SNP of HIF-1α gene (HIF-1α) on prognosis in early-stage ccRCC (pT1a, pT1b, and pT2). Mutational analysis of the entire VHL sequence and the genotyping of HIF-1α C1772T SNP were performed together with VHL promoter methylation analysis and loss of heterozygosis (LOH) analysis at (3p25) locus. Data obtained were correlated with VHL and HIF-1α protein expression and with tumor-specific survival (TSS). VHL mutations, methylation status, and LOH were detected in 51, 11, and 12% of cases, respectively. Our results support the association between biallelic alterations and/or VHL silencing with a worse TSS. Moreover, we found a significant association between the HIF-1α C1772C genotype and a worse TSS. The same association was found when testing the presence of HIF-1α protein in the nucleus. Our results highlight the role of VHL/HIF-1α pathway in RCC and support the molecular heterogeneity of early-stage ccRCC. More important, we show the involvement of HIF-1α C1772T SNP in ccRCC progression.

Immunohistochemical analysis of prognostic protein markers for primary localized clear cell renal cell carcinoma

Recurrence is not reliably predictable in localized clear cell renal cell carcinoma. Proteinmarkers could improve predictive accuracy. Tissue-microarrays from 132 patients with primary localized ccRCC were immunohistochemically analyzed for VHL, Ki67, p53, p21, survivin, and, for microvessel-density, UEA-1. Nuclear stainings of Ki67, p21, and survivin were significantly associated with disease-specific survival and increased predictive ability from 74% to 76%, 77%, and 78%, respectively in a multivariate model including T-stage and Fuhrman grade. A score-variable, combining Ki67-, p21-, and nS-staining identified a subset of patients with high risk of disease recurrence and increased predictive ability in the multivariate model to 84%.

Prognostic factors in patients with advanced renal cell carcinoma

BACKGROUND

The purpose of this study was to evaluate prognostic factors in patients with RCC.

MATERIALS AND METHODS

The expression of several biomarkers were measured by immunohistochemistry (IHC), together with 2 analytic factors (thrombocytosis and neutrophilia), in 135 patients with advanced RCC treated with new targeted drugs (NTDs) (n = 67) and/or cytokines (CKs) (n = 68)-with 23 of the patients who received CKs also receiving NTDs-between July 1996 and February 2010. Relationships with overall survival (OS) and progression-free survival (PFS) were searched for.

RESULTS

Univariate statistical analysis revealed that high expression of hypoxia-inducible factor-1α (HIF-1α) correlated with poor prognosis in NTD treatment (PFS, 5.4 vs. 13.5, low expression months; P = .033) and CK treatment (PFS, 3.3 vs. 5.7, low expression; P = .003). Overexpression of carbonic anhydrase IX (CAIX) was associated with better prognosis with NTD treatment (OS, 32.1 vs. 7.8 months; P < .001) and CK treatment (OS, 32.9 vs. 5.9 months; P = .001). Positive PTEN was related to good prognosis with sunitinib (PFS, 15.1 vs. 6.5 months; P = .003) and CKs (OS, 13.7 vs. 7.9 months; P = .039). Increased expression of p21 was related to poor prognosis with NTD treatment (PFS, 5.9 vs. 16.8 months; P = .024) and CK treatment (PFS, 3.9 vs. 7.5 months; P < .001) Thrombocytosis was related to poor prognosis with NTDs (OS, 15.9 vs. 26.7 months; P = .007) and CKs (OS, 5.9 vs. 14.3 months; P = .010). Neutrophilia was related to poor prognosis with NTDs (OS, 17.6 vs. 25.4 months; P = .063) and CKs (OS, 5.9 vs. 12.8 months; P = .035). Multivariate analysis revealed that overexpression of CAIX was a favorable prognostic factor independent of PFS (hazard ratio [HR], 0.107; P < .001) and OS (HR, 0.055; P < .001).

CONCLUSIONS

HIF-1α, PTEN, p21, thrombocytosis, neutrophilia, and CAIX in particular are useful prognostic factors in patients with advanced RCC.

Searching for Hif1-α interacting proteins in renal cell carcinoma

INTRODUCTION

Kidney tumours are frequently characterised by hypoxic conditions due to a local imbalance between oxygen (O2) supply and consumption. Hif1-α regulates angiogenesis, tumour growth, tumour progression, metastatic spread, and glucose metabolism by acting as a transcription factor for relevant genes. Here, we describe an immunohistochemical study of Hif1-α, a comprehensive computational study of Hif1-α interacting proteins (HIPs), an analysis correlating expression levels of Hif1-α with upstream and downstream proteins, and an analysis of the utility of Hif1-α for prognosis in a cohort of patients with renal cell carcinoma.

MATERIALS AND METHODS

The patient cohort included 80 patients. For immunohistochemistry evaluation, tissue microarrays were constructed. The IntAct, MINT, and BOND databases were used for the HIP approach. The Kruskal-Wallis test was used for comparing protein expression with pathology measurements. Correlation was expressed as the Pearson coefficient.

RESULTS

Hif1-α expression correlates significantly with the "clear" histological subtype of renal cell carcinoma (p < 0.01). The samples with the worst prognoses related to the pathological variables analysed showed the highest levels of Hif1-α expression. Significant correlations were found with Bcl-2, CAIX, C-kit, EGFR, TGF-β, proteins of the VEGF family, proteins related to differentiation (such as Notch1 and Notch3) and certain metabolic enzymes. Bioinformatic analysis suggested 45 evidence-based HIPs and 4 complexes involving protein Hif1-α.

CONCLUSIONS

This work summarises the multifaceted role of Hif1-α in the pathology of renal cell carcinomas, and it identifies HIPs that could help provide mechanistic explanations for the different behaviours seen in tumours.

Microtubular stability affects pVHL-mediated regulation of HIF-1alpha via the p38/MAPK pathway in hypoxic cardiomyocytes

Background

Our previous research found that structural changes of the microtubule network influence glycolysis in cardiomyocytes by regulating the hypoxia-inducible factor (HIF)-1α during the early stages of hypoxia. However, little is known about the underlying regulatory mechanism of the changes of HIF-1α caused by microtubule network alternation. The von Hippel-Lindau tumor suppressor protein (pVHL), as a ubiquitin ligase, is best understood as a negative regulator of HIF-1α.

Methodology/Principal Findings

In primary rat cardiomyocytes and H9c2 cardiac cells, microtubule-stabilization was achieved by pretreating with paclitaxel or transfection of microtubule-associated protein 4 (MAP4) overexpression plasmids and microtubule–depolymerization was achieved by pretreating with colchicine or transfection of MAP4 siRNA before hypoxia treatment. Recombinant adenovirus vectors for overexpressing pVHL or silencing of pVHL expression were constructed and transfected in primary rat cardiomyocytes and H9c2 cells. With different microtubule-stabilizing and -depolymerizing treaments, we demonstrated that the protein levels of HIF-1α were down-regulated through overexpression of pVHL and were up-regulated through knockdown of pVHL in hypoxic cardiomyocytes. Importantly, microtubular structure breakdown activated p38/MAPK pathway, accompanied with the upregulation of pVHL. In coincidence, we found that SB203580, a p38/MAPK inhibitor decreased pVHL while MKK6 (Glu) overexpression increased pVHL in the microtubule network altered-hypoxic cardiomyocytes and H9c2 cells.

Conclusions/Significance

This study suggests that pVHL plays an important role in the regulation of HIF-1α caused by the changes of microtubular structure and the p38/MAPK pathway participates in the process of pVHL change following microtubule network alteration in hypoxic cardiomyocytes.

Immunoexpression status and prognostic value of mTOR and hypoxia-induced pathway members in primary and metastatic clear cell renal cell carcinomas

The need for effective targeted therapies for renal cell carcinomas (RCCs) has fueled the interest for understanding molecular pathways involved in the oncogenesis of kidney tumors. Aiming to analyze the expression status and prognostic significance of mTOR and hypoxia-induced pathway members in patients with clear cell RCC (ccRCC), tissue microarrays were constructed from 135 primary and 41 metastatic ccRCCs. Immunoexpression levels were compared and correlated with clinicopathologic parameters and outcome. PTEN levels were significantly lower in primary and metastatic ccRCCs compared with benign tissues (P<0.001). Levels of phos-AKT, phos-S6, and 4E-binding protein-1 (4EBP1) were higher in metastatic ccRCC (P≤0.001). For phos-S6 and 4EBP1, levels were higher in primary ccRCC compared with benign tissues (P<0.001). c-MYC levels were higher in metastatic ccRCC (P<0.0001), and incremental p27 levels were observed in benign, primary ccRCC, and metastatic ccRCC (P<0.0001). HIF-1α levels were significantly higher in primary and metastatic ccRCCs compared with benign tissues (P<0.0001). In primary ccRCC, levels of all mTOR and hypoxia-induced pathway members were significantly associated with pT stage (P≤0.036), p27 levels with Fuhrman grade (P=0.031), and 4EBP1, p27, and HIF-1α levels with tumor size (P≤0.025). Tumor size, HIF-1α, and phos-S6 levels were associated with disease-specific survival (DSS) (P≤0.032) and tumor progression (P≤0.043). In conclusion, both mTOR and hypoxia-induced pathways were activated in primary and metastatic ccRCC. PTEN loss seems to be an early event during tumorigenesis. Tumor size, HIF-1α, and phos-S6 expression were found to be independent predictors of both DSS and tumor progression in primary ccRCC.

Expression of hypoxia inducible factor-1α and 2α in conventional renal cell carcinoma with or without sarcomatoid differentiation

OBJECTIVES

Expressions of hypoxia inducible factor (HIF)-1α and HIF-2α in epithelial and sarcomatoid components from the same patients with clear cell renal cell carcinoma (RCC) are lacking. We performed this study to define better the correlations among these molecules in RCC tissues.

MATERIALS AND METHODS

Immunohistochemical staining of paraffin sections for HIF-1α and HIF-2α was performed in 24 cases of RCC with sarcomatoid differentiation using a streptavidin-peroxidase procedure. Control samples were collected from 58 patients with no sarcomatoid differentiation matched to cases by age, gender, and TNM stage.

RESULTS

HIF-1α was more expressed within the epithelial component of clear cell RCC with no sarcomatoid differentiation (82.8%) than within that with sarcomatoid differentiation (66.7%). HIF-2α was expressed in most of the epithelial component, regardless of the sarcomatoid differentiation. However, HIF-1α and HIF-2α were not expressed in the sarcomatoid component in about 50.0% of clear cell RCC regardless of the sarcomatoid differentiation. Multivariate Cox proportional hazards model analysis showed that HIF-1α expression was an independent predictor of cancer-specific survival in clear cell RCC with sarcomatoid differentiation (P = 0.029).

CONCLUSIONS

HIF-1α and HIF-2α are not expressed in the sarcomatoid component in about a half of clear cell RCC with sarcomatoid differentiation, while HIF-2α was consistently overexpressed in the epithelial component in a majority of the tumors. Only HIF-1α expression regardless of tumor component is an independent prognostic factor in clear cell RCC with sarcomatoid differentiation.

Xp11 translocation renal cell carcinoma (RCC): extended immunohistochemical profile emphasizing novel RCC markers

Xp11 translocation renal cell carcinoma (RCC) harbor various TFE3 gene fusions, and are known to underexpress epithelial immunohistochemical (IHC) markers such as cytokeratin and EMA relative to usual adult type RCC; however, their profile in reference to other IHC markers that are differentially expressed in other subtypes of RCC has not been systematically assessed. Few therapeutic targets have been identified in these aggressive cancers. We created 2 tissue microarrays (TMA) containing five 1.4-mm cores from each of 21 Xp11 translocation RCC (all confirmed by TFE3 IHC, 6 further confirmed by genetics), 7 clear cell RCC (CCRCC), and 6 papillary RCC (PRCC). These TMA were labeled for a panel of IHC markers. In contrast to earlier published data, Xp11 translocation RCC frequently expressed renal transcription factors PAX8 (16/21 cases) and PAX2 (14/21 cases), whereas only 1 of 21 cases focally expressed MiTF and only 5 of 21 overexpressed p21. Although experimental data suggest otherwise, Xp11 translocation RCC did not express WT-1 (0/21 cases). Although 24% of Xp11 translocation RCC expressed HIF-1alpha (like CCRCC), unlike CCRCC CA IX expression was characteristically only focal (mean 6% cell labeling) in Xp11 translocation RCC. Other markers preferentially expressed in CCRCC or PRCC, such as HIG-2, claudin 7, and EpCAM, yielded inconsistent results in Xp11 translocation RCC. Xp11 translocation RCC infrequently expressed Ksp-cadherin (3/21 cases) and c-kit (0/21 cases), markers frequently expressed in chromophobe RCC. Using an H-score that is the product of intensity and percentage labeling, Xp11 translocation RCC expressed higher levels of phosphorylated S6, a measure of mTOR pathway activation (mean H score=88), than did CCRCC (mean H score=54) or PRCC (mean H score=44). In conclusion, in contrast to prior reports, Xp11 translocation RCC usually express PAX2 and PAX8 but do not usually express MiTF. Although they may express HIF-1alpha, they only focally express the downstream target CA IX. They inconsistently express markers associated with other RCC subtypes, further highlighting the lack of specificity of the latter markers. TFE3 and Cathepsin K remain the most sensitive and specific markers of these neoplasms. Elevated expression of phosphorylated S6 in Xp11 translocation RCC suggests the mTOR pathway as an attractive potential therapeutic target for these neoplasms.

Antisense HIF-1alpha prevents acquired tumor resistance to angiostatin gene therapy

Angiostatin is a naturally occurring inhibitor of angiogenesis that is being developed as a drug to fight cancer. In this study we reveal that EL-4 tumors established in mice rapidly develop resistance to angiostatin gene therapy by upregulating hypoxia-inducible pathways. Angiostatin initially delayed tumor growth for 6 days by reducing blood vessel density. However, tumors quickly responded by upregulating the production of hypoxia-inducible factor-1alpha (HIF-1alpha) and its effector vascular endothelial growth factor (VEGF) in response to increasing tumor hypoxia, leading to restored angiogenesis and rapid tumor growth. Theoretically, blockade of HIF-1 should prevent resistance to anti-angiogenic therapy by preventing a tumor from responding to induced hypoxia. Antisense HIF-1alpha inhibited the expression of HIF-1alpha and of the HIF-1 effectors VEGF, glucose transporter-1 and lactate dehydrogenase. As a monotherapy, it was effective in eradicating small 0.1 cm diameter tumors, but only delayed the growth of large 0.4 cm diameter tumors. In contrast, timed injection of a combination of angiostatin and antisense HIF-1alpha plasmids completely eradicated large EL-4 tumors within 2 weeks, and prevented upregulation of hypoxia-inducible pathways induced by angiostatin. The data indicate that blocking hypoxia-inducible pathways by antisense HIF-1alpha can circumvent hypoxia-induced drug resistance and thereby augment the efficacy of anti-angiogenic therapies.

Real-time imaging of HIF-1alpha stabilization and degradation

HIF-1α is overexpressed in many human cancers compared to normal tissues due to the interaction of a multiplicity of factors and pathways that reflect specific genetic alterations and extracellular stimuli. We developed two HIF-1α chimeric reporter systems, HIF-1α/FLuc and HIF-1α(ΔODDD)/FLuc, to investigate the tightly controlled level of HIF-1α protein in normal (NIH3T3 and HEK293) and glioma (U87) cells. These reporter systems provided an opportunity to investigate the degradation of HIF-1α in different cell lines, both in culture and in xenografts. Using immunofluorescence microscopy, we observed different patterns of subcellular localization of HIF-1α/FLuc fusion protein between normal cells and cancer cells; similar differences were observed for HIF-1α in non-transduced, wild-type cells. A dynamic cytoplasmic-nuclear exchange of the fusion protein and HIF-1α was observed in NIH3T3 and HEK293 cells under different conditions (normoxia, CoCl₂ treatment and hypoxia). In contrast, U87 cells showed a more persistent nuclear localization pattern that was less affected by different growing conditions. Employing a kinetic model for protein degradation, we were able to distinguish two components of HIF-1α/FLuc protein degradation and quantify the half-life of HIF-1α fusion proteins. The rapid clearance component (t_1/2 ∼4–6 min) was abolished by the hypoxia-mimetic CoCl_2, MG132 treatment and deletion of ODD domain, and reflects the oxygen/VHL-dependent degradation pathway. The slow clearance component (t_1/2 ∼200 min) is consistent with other unidentified non-oxygen/VHL-dependent degradation pathways. Overall, the continuous bioluminescence readout of HIF-1α/FLuc stabilization in vitro and in vivo will facilitate the development and validation of therapeutics that affect the stability and accumulation of HIF-1α.

Hypoxia inducible factor-1alpha correlates with vascular endothelial growth factor A and C indicating worse prognosis in clear cell renal cell carcinoma

BACKGROUND

The role of angiogenesis in the pathogenesis of renal cell carcinoma is well recognized, however, the influence of tumor cells in this activity has not yet been fully clarified. The aim of this study was to analyze the expression of hypoxia inducible factor-1alpha (HIF-1alpha), a regulatory factor of angiogenic switch, in comparison to vascular endothelial growth factor A and C (VEGF-A and VEGF-C), recognized to be involved in blood and lymph vessel neoangiogenesis, with potential association in the prognosis of patients with renal cell carcinoma.

METHODS

Ninety-four patients with diagnosis of clear cell renal cell carcinomas (CCRCC), all clinicopathological characteristics and overall survival were unrolled in this study. Immunohistochemicaly VEGF-A, VEGF-C, HIF-1alpha and Ki67 were detected on tumor cells and the staining was performed on tissue microarrays (TMA). The staining was evaluated as a percentage of cytoplasmic or nuclear positive tumor cells.

RESULTS

Variable expression of all three proteins was confirmed. Both angiogenic factors demonstrated perimembranous or diffuse cytoplasmic staining, with diffuse pattern positively associated (p < 0.001). Nuclear HIF-1alpha expression (nHIF-1alpha) showed inverse correlation with diffuse cytoplasmic VEGF-A (p = 0.002) and VEGF-C (p = 0.053), while cytoplasmic HIF-1alpha expression (cHIF-1alpha) showed positive correlation with diffuse staining of both angiogenic factors (p < 0.001; p < 0.001, respectively). In comparison to clinicopathological characteristics, a higher nuclear grade (p = 0.006; p < 0.001, respectively), larger tumor size (p = 0.009; p = 0.015, respectively), higher stage (p = 0.023; p = 0.027, respectively) and shorter survival (p = 0.018; p = 0.024, respectively) were associated with overexpression of cHIF-1alpha and diffuse cytoplasmic VEGF-A expression. In contrary, overexpression of nHIF-1alpha was associated with better diagnostic parameters i.e. lower nuclear grade (p = 0.006), smaller tumor size (p = 0.057), and longer survival (p = 0.005).

CONCLUSION

Overexpression of VEGF-A and cHIF-1alpha in tumor cells highlights a more aggressive subtype of CCRCC that might have some clinical implications. The significance of nHIF-1alpha expression associated with better differentiated tumors should be further elucidated.

Prognostic role of histological necrosis for nonmetastatic clear cell renal cell carcinoma: correlation with pathological features and molecular markers

PURPOSE

We defined the prognostic role of tumor necrosis and its extent in nonmetastatic clear cell renal cell carcinoma. Also, we further investigated its pathogenesis by correlating this tumor feature with other pathological characteristics and molecular markers related to the von Hippel Lindau-hypoxia inducible factor pathway and to tumor proliferation.

MATERIALS AND METHODS

A total of 213 patients with nonmetastatic clear cell renal cell carcinoma were evaluated. Mean followup was 66 months. The presence and extent of histological necrosis were correlated with clinicopathological factors, Ki-67 antigen expression calculated by the MIB-1 (Ki-67 antibody) index, pVHL, HIF-1alpha, the tumor infiltrating lymphocyte subset and cancer specific survival.

RESULTS

Histological necrosis was present in 63.8% of clear cell renal cell carcinoma cases. Necrosis was significantly associated with grade and the degree of tumor infiltrating lymphocytes, while its extent correlated significantly with grade, the degree of tumor infiltrating lymphocytes and stage. Tumor necrosis was a significant prognostic factor, which was confirmed even when limiting analysis to patients with intracapsular renal cell carcinoma. On multivariate analysis histological necrosis was not an independent predictor of cancer specific survival. The extent of tumor necrosis was not a significant prognostic factor. The presence and extent of histological necrosis was not associated with high Ki-67 expression and it did not correlate with pVHL expression or with nuclear and cytoplasmic HIF-1alpha expression.

CONCLUSIONS

Based on our results we cannot support histological necrosis and its extent as prognostic factors for clear cell renal cell carcinoma. Efforts should be made to develop nomograms that use routinely available and objective predictor variables. The precise mechanism that causes tumor necrosis remains unknown but the host immune response might significantly contribute to its development.

Recent advances in annular pathobiology provide insights into rim-lesion mediated intervertebral disc degeneration and potential new approaches to annular repair strategies

The objective of this study was to assess the impact of a landmark annular lesion model on our understanding of the etiopathogenesis of IVD degeneration and to appraise current IVD repairative strategies. A number of studies have utilised the Osti sheep model since its development in 1990. The experimental questions posed at that time are covered in this review, as are significant recent advances in annular repair strategies. The ovine model has provided important spatial and temporal insights into the longitudinal development of annular lesions and how they impact on other discal and paradiscal components such as the NP, cartilaginous end plates, zygapophyseal joints and vertebral bone and blood vessels. Important recent advances have been made in biomatrix design for IVD repair and in the oriented and dynamic culture of annular fibrochondrocytes into planar, spatially relevant, annular type structures. The development of hyaluronan hydrogels capable of rapid in situ gelation offer the possibility of supplementation of matrices with cells and other biomimetics and represent a significant advance in biopolymer design. New generation biological glues and self-curing acrylic formulations which may be augmented with slow delivery biomimetics in microcarriers may also find application in the non-surgical repair of annular defects. Despite major advances, significant technical challenges still have to be overcome before the biological repair of this intractable connective tissue becomes a realistic alternative to conventional surgical intervention for the treatment of chronic degenerate IVDs.

Re: prognostic relevance of capsular involvement and collecting system invasion in stage I and II renal cell carcinoma

Klatte and coworkers examined the prognostic relevance of capsular involvement with no invasion of the perinephric fat and collecting system invasion in a series of 519 patients with intracapsular renal cell carcinoma (RCC) treated with partial or radical nephrectomy and followed for a median of 49 mo (range: 1-199 mo). Capsular involvement and collecting system invasion were reported in 21.6% and 7.5% of patients, respectively. Capsular involvement was significantly associated with a higher nuclear grade and larger tumors, whereas collecting system invasion was significantly associated only with microvascular invasion. In addition, capsular involvement and collecting system invasion were not associated with each other, but had a significant impact on recurrence-free survival (p = 0.007 and p < 0.001, respectively). Interestingly, patients with capsular involvement had the same recurrence-free survival as patients diagnosed as having pT3a N0 M0 RCC. In multivariate analysis, both capsular involvement and collecting system invasion were independent predictors of recurrence-free survival with a reported risk ratio of 1.84 and 3.78, respectively.