CD 9 and vimentin distinguish clear cell from chromophobe renal cell carcinoma

An information theoretic approach to detecting spatially varying genes

A key step in spatial transcriptomics is identifying genes with spatially varying expression patterns. We adopt an information theoretic perspective to this problem by equating the degree of spatial coherence with the Jensen-Shannon divergence between pairs of nearby cells and pairs of distant cells. To avoid the notoriously difficult problem of estimating information theoretic divergences, we use modern approximation techniques to implement a computationally efficient algorithm designed to scale with in situ spatial transcriptomics technologies. In addition to being highly scalable, we show that our method, which we call maximization of spatial information (Maxspin), improves accuracy across several spatial transcriptomics platforms and a variety of simulations when compared with a variety of state-of-the-art methods. To further demonstrate the method, we generated in situ spatial transcriptomics data in a renal cell carcinoma sample using the CosMx Spatial Molecular Imager and used Maxspin to reveal novel spatial patterns of tumor cell gene expression.

Cancer Vaccines, Adjuvants, and Delivery Systems

Vaccination was first pioneered in the 18th century by Edward Jenner and eventually led to the development of the smallpox vaccine and subsequently the eradication of smallpox. The impact of vaccination to prevent infectious diseases has been outstanding with many infections being prevented and a significant decrease in mortality worldwide. Cancer vaccines aim to clear active disease instead of aiming to prevent disease, the only exception being the recently approved vaccine that prevents cancers caused by the Human Papillomavirus. The development of therapeutic cancer vaccines has been disappointing with many early cancer vaccines that showed promise in preclinical models often failing to translate into efficacy in the clinic. In this review we provide an overview of the current vaccine platforms, adjuvants and delivery systems that are currently being investigated or have been approved. With the advent of immune checkpoint inhibitors, we also review the potential of these to be used with cancer vaccines to improve efficacy and help to overcome the immune suppressive tumor microenvironment.

Prognostic Value of Vimentin Is Associated With Immunosuppression in Metastatic Renal Cell Carcinoma

Introduction: Vimentin, a classical marker of epithelial–mesenchymal transition, reflects the invasiveness of cancer cells. Its role in the genesis and progression of tumor has been reported in various cancers, including renal cell carcinoma. However, the impact of vimentin on tumor microenvironment, particularly its implication with tumor-infiltrating immune cells, is unknown.

Methods: We conducted this study in 231 patients with metastatic renal cell carcinoma (mRCC) to determine the potential relationship between vimentin and immune status. Using immunohistochemical staining, expression of vimentin, CD8, FOXP3, programmed cell death protein 1 (PD-1), and programmed cell death ligand 1 (PD-L1) were evaluated in resected tumor tissue. Kaplan–Meier analysis and Cox regression models were used for survival analysis. Chi-square test, Fisher exact test, and Mann–Whitney U-test were used for comparison between vimentin high and low groups.

Results: High expression of vimentin, stroma PD-L1, and PD-1 indicated poor overall survival, whereas low regulatory T cell or high CD8+ T cell infiltration indicated long overall survival. Stroma PD-L1 (P = 0.030), vimentin (P = 0.026) expression, and CD8⁺ T cell infiltration (P < 0.001) were independent prognostic factors in mRCC. High vimentin expression was accompanied by high PD-1, PD-L1 expression, and increased regulatory T cell infiltration (all P < 0.001), indicating immunosuppression in the tumor microenvironment.

Conclusions: We revealed that vimentin expression was associated with immunosuppression in mRCC, and the immune-suppressive status might be possibly posed by PD-1/PD-L1. Patients with high vimentin expression may acquire potential benefit from the recently approved PD-1/PD-L1 inhibitors. However, further clinical trials are needed to validate our findings.

The different expression of glycogen phosphorylases in renal clear cell renal carcinoma and chromophobe renal carcinoma

Background

The various pathogenesis between Clear cell renal carcinoma (CCRCC) and Chromophobe renal carcinoma (CHRCC) contributes to the different tumor growth rate and metastasis. In this study, we explored the distinct proteomic profiles between these two cancers and found different expression of glycogen phosphorylases in two cancers.

Methods

We explored novel targets by proteomics. Five CCRCC cases and five CHRCC cases were selected for tandem mass tag-labeling liquid chromatography-mass spectroscopy (LC–MS). Gene ontology and KEGG pathway were applied for bioinformatic analysis. Glycogen phosphorylases were detected by Western blotting.

Results

CHRCC were younger, more commonly female, and had larger tumors compared to those with CCRCC. 101 differentially expressed proteins (DEPs) in CCRCC and 235 DEPs in CHRCC were detected by LC–MS. It was found that disruption of metabolic pathways, epithelial cell differentiation, and cell response were the common characters for two tumor types. Activation of cell–cell adhesion and oxidation–reduction process stimulate CCRCC growth and epithelial cell differentiation and transferrin transport was involved in CHRCC growth, We also found that oxidative phosphorylation is activated in CHRCC and inhibited in CCRCC. More importantly, we found and confirmed that upregulation of glycogen phosphorylase liver type in CCRCC and glycogen phosphorylase brain type in CHRCC mediated differential glycogenolysis in the two tumor types, which could serve as potential therapeutic targets.

Conclusion

We found different expression of glycogen phosphorylases in CCRCC and CHRCC by quantitative proteomics, which provides potential therapeutic targets in the future.

Post-translational modifications such as citrullination are excellent targets for cancer therapy

Under conditions of cellular stress, proteins can be post-translationally modified causing them to be recognized by the immune system. One such stress-induced post-translational modification (siPTM) is citrullination, the conversion of arginine residues to citrulline by peptidylarginine deiminase (PAD) enzymes. PAD enzymes are activated by millimolar concentrations of calcium which can occur during apoptosis, leading to precipitation of proteins, their subsequent uptake by B cells and stimulation of antibody responses. Detection of anti-citrullinated protein antibodies (ACPAs) is a diagnostic of rheumatoid arthritis (RA), where immune complexes stimulate inflammation around the joints. More recently, autophagy has been shown to play a role in the presentation of citrullinated peptides on MHC class II molecules to CD4⁺ helper T cells, suggesting that citrullination may be a way of alerting immune cells to cellular stress. Additionally, inflammation-induced IFNγ and concomitant MHC class II expression on target cells contributes to immune activation. Stressful conditions in the tumor microenvironment induce autophagy in cancer cells as a pro-survival mechanism. Cancer cells also over express PAD enzymes and in light of this the hypothesis that citrullinated peptides stimulate CD4⁺ T cell responses that would recognize these siPTM's produced during autophagy has been investigated. The induction of potent citrullinated peptide-specific CD4 responses has been shown in both humans and HLA transgenic mouse models. Responses in mouse models resulted in potent anti-tumour responses against tumours expressing either constitutive or IFNγ-inducible MHC class II. The anti-tumour effect relied upon direct recognition of tumours by specific CD4 T cells suggesting that citrullinated peptides are attractive targets for cancer vaccines.

Vimentin Overexpressions Induced by Cell Hypoxia Promote Vasculogenic Mimicry by Renal Cell Carcinoma Cells

Vasculogenic mimicry (VM), the novel approach for tumor cells to obtain blood supply, was reported to be involved in antiangiogenic resistance and poor prognosis in renal cell carcinoma (RCC). However, the molecular mechanisms underlying VM formed by RCC cells are still not clearly depicted. In the present study, we found that OS-RC-2 acquired the VM forming ability accompanied with the increased expressions of Vimentin and AXL and decreased expression of E-Cadherin by CoCl₂ treatment. Downregulation of Vimentin by siRNA severely impaired the capability of OS-RC-2 and 786-O to form VM structures induced by cell hypoxia in vitro. Moreover, knockdown of Vimentin inhibited cell migration and invasion, which could be prompted by hypoxia induction in RCC cells. In our clear cell RCC tissues, we found that VM was positively correlated with Vimentin overexpression and both predicted poor prognosis. In conclusion, Vimentin plays an important role in hypoxia induced VM formation of RCC cells and targeted Vimentin might be beneficial for RCC therapy.

Key miRNAs and target genes played roles in the development of clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (CCRCC) is the most aggressive form of renal cell carcinoma (RCC).

OBJECTIVE

This study was aimed to identify the differentially expressed miRNAs and target genes in CCRCC.

METHODS

The miRNA and mRNA next-generation sequencing data were downloaded from The Cancer Genome Atlas (TCGA) dataset. Differential expression analysis was performed, followed by correlation analysis of miRNA-mRNA. Functional enrichment and survival analysis was also performed.

RESULTS

Seven hundred and eighty-seven patients with CCRCC from TCGA data portal were included in this study. A total of 52 differentially expressed miRNAs were identified in CCRCC. Then 2361 differentially expressed genes (DEGs) were identified. Prediction analysis and correlation analysis revealed that 89 miRNA-mRNA pairs were not only predicted by algorithms but also had a significant inverse relationship. Several differentially expressed miRNAs such as hsa-mir-501 and their target genes including AK1, SLC25A15 and PCDHGC3 had a significant prognostic value for CCRCC patients.

CONCLUSIONS

Alterations of differentially expressed miRNAs and target genes may be involved in the development of CCRCC and can be considered as the prognostic markers for CCRCC.

Vimentin Diversity in Health and Disease

Vimentin is a protein that has been linked to a large variety of pathophysiological conditions, including cataracts, Crohn's disease, rheumatoid arthritis, HIV and cancer. Vimentin has also been shown to regulate a wide spectrum of basic cellular functions. In cells, vimentin assembles into a network of filaments that spans the cytoplasm. It can also be found in smaller, non-filamentous forms that can localise both within cells and within the extracellular microenvironment. The vimentin structure can be altered by subunit exchange, cleavage into different sizes, re-annealing, post-translational modifications and interacting proteins. Together with the observation that different domains of vimentin might have evolved under different selection pressures that defined distinct biological functions for different parts of the protein, the many diverse variants of vimentin might be the cause of its functional diversity. A number of review articles have focussed on the biology and medical aspects of intermediate filament proteins without particular commitment to vimentin, and other reviews have focussed on intermediate filaments in an in vitro context. In contrast, the present review focusses almost exclusively on vimentin, and covers both ex vivo and in vivo data from tissue culture and from living organisms, including a summary of the many phenotypes of vimentin knockout animals. Our aim is to provide a comprehensive overview of the current understanding of the many diverse aspects of vimentin, from biochemical, mechanical, cellular, systems biology and medical perspectives.

Linneg Sca-1high CD49fhigh prostate cancer cells derived from the Hi-Myc mouse model are tumor-initiating cells with basal-epithelial characteristics and differentiation potential in vitro and in vivo

A cell line was established from ventral prostate (VP) tumors of one-year-old Hi-Myc mice. These cells, called HMVP2 cells, are Lin^negSca-1^highCD49f^high with high CD44 and CD29 expression and express CK14, Sca-1 and CD49f (but not CK8), suggesting basal-epithelial characteristics. Furthermore, HMVP2 cells form spheroids and both the cells and spheroids produce tumors in syngeneic mice. After four days of culture, HMVP2 spheroids underwent a gradual transition from Lin^negSca-1^highCD49f^high expression to Lin^negSca-1^lowCD49f^low while a subpopulation of the cells retained the original Lin^negSca-1^highCD49f^high expression pattern. Additional cell subpopulations expressing Lin positive markers were also present suggesting further differentiation of HMVP2 spheroids. Two additional highly tumorigenic cell lines (HMVP2A1 and HMVP2A2) were isolated from HMVP2 cells after subsequent tumor formation in FVB/N mice. Concurrently, we also established cell lines from the VP of 6 months old Hi-Myc mice (named as HMVP1) and FVB/N mice (called NMVP) having less aggressive growth properties compared to the other three cell lines. AR expression was reduced in HMVP2 cells compared to NMVP and HMVP1 cells and almost absent in HMVP2A1 and HMVP2A2 cells. These cell lines will provide valuable tools for further mechanistic studies as well as preclinical studies to evaluate preventive and/or therapeutic agents for prostate cancer.

The association of vimentin and fibronectin gene expression with epithelial-mesenchymal transition and tumor malignancy in colorectal carcinoma

Colorectal cancer is the most common malignancy of the gastrointestinal tract with very high mortality. One of the most distinguishing features for the establishment of an epithelial-mesenchymal transition phenotype is the alteration of mesenchymal markers expression and structural adhesion proteins. We evaluated the significance of vimentin and fibronectin gene expression in relation to invasion and metastasis in CRC patients. Tissue specimens were collected consecutively from forty-five colorectal carcinoma patients during surgeries. Tissues were divided into two separate parts for pathological and molecular assays. In order to histological staging, tissue sections were prepared from formalin-fixed paraffin-embedded blocks and stained with Hematoxylin and Eosin. To quantify gene expression, specimens were dissected and homogenized. Moreover, SW480, SW48, SW948, Caco-2, HT-29 and LS174T as human colon cancer cell lines were obtained and cultured, then molecular analyzing was performed. As results the expression of VIM gene increased in SW480, SW48 and SW948 while it decreased in Caco-2, HT-29 and LS174T. Moreover, FN was up-regulated in Caco-2, HT-29 and SW948, while it was down-regulated in SW480, SW48 and LS174T. In tissues, vimentin and fibronectin expression significantly increased in stromal cells, whereas vimentin decreased in colonic epithelial cells and fibronectin had no significant change. Vimentin and fibronectin expression were changed in tumor tissues. It was found an association between vimentin expression with age and tumor size; over-expression in older age and decreasing in larger tumor size. Furthermore, fibronectin over-expression is correlated to older age and high tumor stages; up-regulation with increasing age and high tumor stages.

Morph-X-Select: Morphology-based tissue aptamer selection for ovarian cancer biomarker discovery

High affinity aptamer-based biomarker discovery has the advantage of simultaneously discovering an aptamer affinity reagent and its target biomarker protein. Here, we demonstrate a morphology-based tissue aptamer selection method that enables us to use tissue sections from individual patients and identify high-affinity aptamers and their associated target proteins in a systematic and accurate way. We created a combinatorial DNA aptamer library that has been modified with thiophosphate substitutions of the phosphate ester backbone at selected 5´dA positions for enhanced nuclease resistance and targeting. Based on morphological assessment, we used image-directed laser microdissection (LMD) to dissect regions of interest bound with the thioaptamer (TA) library and further identified target proteins for the selected TAs. We have successfully identified and characterized the lead candidate TA, V5, as a vimentin-specific sequence that has shown specific binding to tumor vasculature of human ovarian tissue and human microvascular endothelial cells. This new Morph-X-Select method allows us to select high-affinity aptamers and their associated target proteins in a specific and accurate way, and could be used for personalized biomarker discovery to improve medical decision-making and to facilitate the development of targeted therapies to achieve more favorable outcomes.

Selected tumor markers in the routine diagnosis of chromophobe renal cell carcinoma

Renal cell carcinoma is one of the most malignant tumors, affecting men more frequently than women and constituting nearly 90% of all kidney tumors. Chromophobe renal cell carcinoma has been described as a new histological type of renal cell carcinoma. Chromophobe renal cell carcinoma constitutes up to 5% of all cases of kidney cancer. It is characterized by a significant number of deletions in many chromosomes, as well as the loss of entire chromosomes. Chromophobe renal cell carcinoma arises from tubular cells or cells of the macula densa. In contrast to other types of kidney cancer, it occurs with equal frequency in men and women, mostly in the sixth decade of life. It is characterized by a relatively good prognosis and exhibits a low degree of malignancy. Histopathologic diagnosis of ChRCC can be a diagnostic challenge because these tumors may resemble oncocytoma or conventional cancer. Research by Mathers et al. proposed the use of cytokeratin 7 as a marker useful in the differentiation of these changes.

Genomics of chromophobe renal cell carcinoma: implications from a rare tumor for pan-cancer studies

Chromophobe Renal Cell Carcinoma (ChRCC) is a rare subtype of the renal cell carcinomas, a heterogenous group of cancers arising from the nephron. Recently, The Cancer Genome Atlas (TCGA) profiled this understudied disease using multiple data platforms, including whole exome sequencing, whole genome sequencing (WGS), and mitochondrial DNA (mtDNA) sequencing. The insights gained from this study would have implications for other types of kidney cancer as well as for cancer biology in general. Global molecular patterns in ChRCC provided clues as to this cancer's cell of origin, which is distinct from that of the other renal cell carcinomas, illustrating an approach that might be applied towards elucidating the cell of origin of other cancer types. MtDNA sequencing revealed loss-of-function mutations in NADH dehydrogenase subunits, highlighting the role of deregulated metabolism in this and other cancers. Analysis of WGS data led to the discovery of recurrent genomic rearrangements involving TERT promoter region, which were associated with very high expression levels of TERT, pointing to a potential mechanism for TERT deregulation that might be found in other cancers. WGS data, generated by large scale efforts such as TCGA and the International Cancer Genomics Consortium (ICGC), could be more extensively mined across various cancer types, to uncover structural variants, mtDNA mutations, themes of tumor metabolic properties, as well as noncoding point mutations. TCGA's data on ChRCC should continue to serve as a resource for future pan-cancer as well as kidney cancer studies, and highlight the value of investigations into rare tumor types to globally inform principals of cancer biology.

Expression of vimentin and survivin in clear cell renal cell carcinoma and correlation with p53

PURPOSE

This study focuses on investigating the expression correlation of vimentin, survivin and p53 in clear cell renal cell carcinoma (ccRCC) and the clinical significance.

METHODS

The mRNA and protein expression levels of the vimentin, survivin and p53 were determined in ccRCC and adjacent normal renal tissues, using quantitative real-time-polymerase chain reaction (qRT-PCR) and Western blot. We detected the expression and localization of vimentin, survivin and p53 protein in ccRCC by immunohistochemistrical SP method and analyzed the relationships among clinical pathologic parameters and patient prognosis.

RESULTS

The expression of vimentin and survivin was significantly increased in ccRCC compared with adjacent normal renal tissues, which were positively correlated with the pathological grade and clinical stage (P < 0.05). p53 was highly expressed in ccRCC compared with normal tissues (P < 0.05), which was not positively correlated with the pathological grade and clinical stage (P > 0.05). Furthermore, univariate and multivariate analysis showed that high expression levels of vimentin and survivin were independent prognostic indicators for ccRCC. The levels of vimentin and survivin were positively correlated in ccRCC (r = 0.428, P < 0.01).

CONCLUSIONS

Reliable basis about biological behavior and prognosis judgments of ccRCC can be provided by combining detection of vimentin and survivin. Foundation and new ideas for gene therapy of ccRCC may be provided by further studying the relationship among vimentin, survivin and p53 in ccRCC.

Neuronal pentraxin 2 supports clear cell renal cell carcinoma by activating the AMPA-selective glutamate receptor-4

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer and has the highest propensity to manifest as metastatic disease. Recent characterizations of the genetic signature of ccRCC have revealed several factors correlated with tumor cell migration and invasion; however, the specific events driving malignancy are not well defined. Furthermore, there remains a lack of targeted therapies that result in long-term, sustainable response in patients with metastatic disease. We show here that neuronal pentraxin 2 (NPTX2) is overexpressed specifically in ccRCC primary tumors and metastases, and that it contributes to tumor cell viability and promotes cell migration through its interaction with the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR4. We propose NPTX2 as a novel molecular target for therapy for patients with ccRCC diagnosed with or at risk of developing metastatic disease.

Aberrant methylation of the VIM promoter in uterine cervical squamous cell carcinoma

OBJECTIVES

To identify prognosis-associated methylation markers of uterine cervical squamous cell carcinoma (SCC) and to verify potential clinical correlations.

METHODS

A genome-wide methylation array was performed using tissue samples of stage Ib1 (n = 9) and IIa (n = 5) tumors. Methylation levels were quantitatively evaluated by pyrosequencing for 54 tissue samples from SCC patients and 22 samples from normal controls. Clinicopathologic findings were obtained from medical records. Correlation or t test statistics were used to analyze the relationships between methylation levels and clinical features. Survival data were estimated using the Kaplan-Meier method and compared to the log-rank test.

RESULTS

The methylation array identified 32 genes with distinct differences (p < 0.01) between stage Ib1 and IIa disease, and VIM was selected for further evaluation. Pyrosequencing analysis revealed that 40.7% of carcinoma samples had a higher methylation level in the VIM gene compared to the normal controls. VIM methylation status, low FIGO stage, and lack of parametrial involvement were significantly associated with longer disease-free survival (p = 0.036, p = 0.028, and p = 0.001, respectively).

CONCLUSIONS

We profiled 32 genes that might be associated with prognosis in cervical cancer. We further revealed that the VIM gene is frequently methylated in cervical SCC and that its methylation might predict a favorable prognosis.

Oncogenic micro-RNAs and Renal Cell Carcinoma

Tumor formation is a complex process that occurs in different steps and involves many cell types, including tumor cells, endothelial cells, and inflammatory cells, which interact to promote growth of the tumor mass and metastasization. Epigenetic alterations occurring in transformed cells result in de-regulation of miRNA expression (a class of small non-coding RNA that regulates multiple functions), which contributes to tumorigenesis. The specific miRNAs, which have an aberrant expression in tumors, are defined as oncomiRNAs, and may be either over- or under-expressed, but down-regulation is most commonly observed. Renal cell carcinoma (RCC) is a frequent form of urologic tumor, associated with an alteration of multiple signaling pathways. Many molecules involved in the progression of RCCs, such as HIF, VEGF, or mammalian target of rapamycin, are possible targets of de-regulated miRNAs. Within tumor mass, the cancer stem cell (CSC) population is a fundamental component that promotes tumor growth. The CSC hypothesis postulates that CSCs have the unique ability to self-renew and to maintain tumor growth and metastasis. CSCs present in RCC were shown to express the mesenchymal stem cell marker CD105 and to exhibit self-renewal and clonogenic properties, as well as the ability to generate serially transplantable tumors. The phenotype of CSC has been related to the potential to undergo the epithelial–mesenchymal transition, which has been linked to the expression pattern of tumorigenic miRNAs or down-regulation of anti-tumor miRNAs. In addition, the pattern of circulating miRNAs may allow discrimination between healthy and tumor patients. Therefore, a miRNA signature may be used as a tumor biomarker for cancer diagnosis, as well as to classify the risk of relapse and metastasis, and for a guide for therapy.

DNA-aptamer targeting vimentin for tumor therapy in vivo

In recent years, new prospects for the use of nucleic acids as anticancer drugs have been discovered. Aptamers for intracellular targets can regulate cellular functions and cause cell death or proliferation. However, intracellular aptamers have limited use for therapeutic applications due to their low bioavailability. In this work, we selected DNA aptamers to cell organelles and nucleus of cancer cells, and showed that an aptamer NAS-24 binds to vimentin and causes apoptosis of mouse ascites adenocarcinoma cells in vitro and in vivo. To deliver the aptamer NAS-24 inside cells, natural polysaccharide arabinogalactan was used as a carrier reagent. The mixture of arabinogalactan and NAS-24 was injected intraperitonealy for 5 days into mice with adenocarcinoma and inhibited adenocarcinoma growth more effectively than free arabinogalactan or the aptamer alone. The use of aptamers to intracellular targets together with arabinogalactan becomes a promising approach for anticancer therapy.

Tumor suppressive microRNA‑138 contributes to cell migration and invasion through its targeting of vimentin in renal cell carcinoma

Many studies have recently suggested that microRNAs (miRNAs) contribute to the development of various types of human cancers as well as to their invasive and metastatic capacities. Previously, our miRNA expression signature of renal cell carcinoma (RCC) revealed that microRNA‑138 (miR‑138) was significantly reduced in cancer cells. The aim of the present study was to investigate the functional significance of miR‑138 and to identify its target genes in RCC cells. Restoration of mature miR‑138 in two RCC cell lines (A498 and 786‑O) caused changes in the bleb-like cell morphology, characteristics of the epithelial-mesenchymal transition (EMT). Restoration also significantly inhibited migration and invasion in the two RCC cell lines, suggesting that miR‑138 functions as a tumor suppressor. Genome-wide gene expression analysis (miR‑138 transfectants and RCC clinical specimens) and TargetScan database studies showed that vimentin (VIM) is a promising candidate target gene of miR‑138. It is well known that VIM is one of the most widely expressed mammalian intermediate filament proteins. Recent studies showed that VIM functions in cell adhesion, migration, survival and cell signaling processes via dynamic assembly/disassembly in cancer cells. We focused on VIM and investigated whether VIM was regulated by tumor suppressive miR‑138 and contributed to cancer cell migration and invasion in RCC cells. Restoration of miR‑138 in RCC cell lines suppressed VIM expression at both the mRNA and protein levels. Silencing studies of VIM in RCC cell lines demonstrated significant inhibition of cell migration and invasion activities in si-VIM transfectants. In clinical specimens of RCC, the expression levels of VIM were significantly upregulated in cancer tissues compared to adjacent non-cancerous tissues. Furthermore, immunohistochemistry showed that VIM expression levels in RCC specimens were significantly higher than those in normal renal tissues. These data suggest that VIM may function as an oncogene and is regulated by tumor suppressive miR‑138. The existence of a tumor suppressive miR‑138-mediated oncogenic pathway provides new insights into the potential mechanisms of RCC oncogenesis and metastasis.

Vimentin in cancer and its potential as a molecular target for cancer therapy

Vimentin, a major constituent of the intermediate filament family of proteins, is ubiquitously expressed in normal mesenchymal cells and is known to maintain cellular integrity and provide resistance against stress. Vimentin is overexpressed in various epithelial cancers, including prostate cancer, gastrointestinal tumors, tumors of the central nervous system, breast cancer, malignant melanoma, and lung cancer. Vimentin's overexpression in cancer correlates well with accelerated tumor growth, invasion, and poor prognosis; however, the role of vimentin in cancer progression remains obscure. In recent years, vimentin has been recognized as a marker for epithelial-mesenchymal transition (EMT). Although EMT is associated with several tumorigenic events, vimentin's role in the underlying events mediating these processes remains unknown. By virtue of its overexpression in cancer and its association with tumor growth and metastasis, vimentin serves as an attractive potential target for cancer therapy; however, more research would be crucial to evaluate its specific role in cancer. Our recent discovery of a vimentin-binding mini-peptide has generated further impetus for vimentin-targeted tumor-specific therapy. Furthermore, research directed toward elucidating the role of vimentin in various signaling pathways would reveal new approaches for the development of therapeutic agents. This review summarizes the expression and functions of vimentin in various types of cancer and suggests some directions toward future cancer therapy utilizing vimentin as a potential molecular target.

Hypoxia negatively regulates heparan sulfatase 2 expression in renal cancer cell lines

Inactivation of von Hippel-Lindau (VHL), a tumor suppressor gene is often associated with clear cell renal cell carcinoma (ccRCC). VHL inactivation leads to multitude of responses including enhanced growth factor signaling such as bFGF2, SDF-1α, and HGF. Here, we have identified a novel VHL-inducible gene, heparan sulfatase 2 (HSulf-2) that attenuates heparan-binding growth factor such as bFGF2 signaling. VHL-mediated HIF-1 alpha degradation was essential to restore HSulf-2 expression. Mechanistically, HSulf-2 negatively regulated vimentin expression and knockdown of vimentin abolished cell migration. This study reveals a novel layer of regulation of heparan-binding growth factor signaling via modulation of heparan sulfate by HSulf-2 in ccRCC.