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

Laser-activable murine ferritin nanocage for chemo-photothermal therapy of colorectal cancer

Chemotherapy, as a conventional strategy for tumor therapy, often leads to unsatisfied therapeutic effect due to the multi-drug resistance and the serious side effects. Herein, we genetically engineered a thermal-responsive murine Ferritin (mHFn) to specifically deliver mitoxantrone (MTO, a chemotherapeutic and photothermal agent) to tumor tissue for the chemotherapy and photothermal combined therapy of colorectal cancer, thanks to the high affinity of mHFn to transferrin receptor that highly expressed on tumor cells. The thermal-sensitive channels on mHFn allowed the effective encapsulation of MTO in vitro and the laser-controlled release of MTO in vivo. Upon irradiation with a 660 nm laser, the raised temperature triggered the opening of the thermal-sensitive channel in mHFn nanocage, resulting in the controlled and rapid release of MTO. Consequently, a significant amount of reactive oxygen species was generated, causing mitochondrial collapse and tumor cell death. The photothermal-sensitive controlled release, low systemic cytotoxicity, and excellent synergistic tumor eradication ability in vivo made mHFn@MTO a promising candidate for chemo-photothermal combination therapy against colorectal cancer.

The categorizations of vasculogenic mimicry in clear cell renal cell carcinoma unveil inherent connections with clinical and immune features

Background: Clear cell renal cell carcinoma (ccRCC) stands as the prevailing variant kidney cancer in humans. Unfortunately, patients with disseminated RCC at diagnosis often have a diminished prognosis. Rapid tumor growth necessitates efficient blood supply for oxygen and nutrients, involving the circulation of blood from vessels to tumor tissues, facilitating tumor cell entry into the extracellular matrix. Vasculogenic mimicry (VM) significantly contributes to tumor growth and metastasis. Within this investigation, we identified vasculogenic mimicry-related genes (VMRGs) by analyzing data from 607 cases of kidney renal clear cell carcinoma (KIRC) in The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/). These findings offer insights into ccRCC progression and metastasis. Method: We identified VMRGs-related subtypes using consistent clustering methods. The signature of the VMRGs was created using univariate Cox regression and LASSO Cox regression analyses. To evaluate differences in immune cell infiltration, we employed ssGSEA. Afterwards, we created an innovative risk assessment model, known as the VM index, along with a nomogram to forecast the prognosis of ccRCC. Additionally, we verified the expression of an important gene related to VM, peroxiredoxin 2 (PRDX2), in tissue samples. Furthermore, we assessed the sensitivity to drugs in various groups by utilizing the pRRophetic R package. Results: Significant predictors of survival rates in both high- and low-risk groups of KIRC patients were identified as VMRGs. The independent prognostic factors for RCC were confirmed by both univariate and multivariate Cox regression analyses, validating VMRG risk signatures. Differences were observed in drug sensitivity, immune checkpoint expression, and responses to immune therapy between patients classified into high- and low-VMRG-risk groups. Our nomograms consistently demonstrated precise predictive capabilities. Finally, we experimentally verified PRDX2 expression levels and their impact on prognosis. Conclusion: The signature predicts patient prognosis and therapy response, laying the groundwork for future clinical strategies in treating ccRCC patients.

The immunoreactivity of GLI1 and VEGFA is a potential prognostic factor in kidney renal clear cell carcinoma

Kidney renal clear cell carcinoma (KIRC) is the most common type of kidney cancer and its pathogenesis is strongly associated with VHL-HIF-VEGF signaling. SHH ligand is the upstream SHH pathway regulator, while GLI1 is its major effector that stimulates as a transcription factor, i.a. expression of VEGFA gene. The aim of present study was to assess the prognostic significance of SHH, GLI1 and VEGFA immunoreactivity in KIRC tissues. The analysis included paired tumor and normal samples from 34 patients with KIRC. The immunoreactivity of SHH, GLI1 and VEGFA proteins was determined by immunohistochemical (IHC) renal tissues staining. The IHC staining results were assessed using the immunoreactive score (IRS) method which takes into account the number of cells showing a positive reaction and the intensity of the reaction. Increased GLI1 protein immunoreactivity was observed in KIRC tissues, especially in early-stage tumors, according to the TNM classification. Elevated expression of the VEGFA protein was noted primarily in high-grade KIRC samples according to the Fuhrman/WHO/ISUP scale. Moreover, a directly proportional correlation was observed between SHH and VEGFA immunoreactivity in TNM 3 + 4 and Fuhrman/ISUP/WHO 3 + 4 tumor tissues as well as in samples of patients with shorter survival. We also observed an association between shorter patient survival as well as increased and decreased immunoreactivity, of the VEGFA and GLI1, respectively. The aforementioned findings suggest that the expression pattern of SHH, GLI1 and VEGFA demonstrates prognostic potential in KIRC.

Potential therapeutic target secretogranin II might cooperate with hypoxia-inducible factor 1α in sunitinib-resistant renal cell carcinoma

Multitargeted receptor tyrosine kinase inhibitors, including vascular endothelial growth factor (VEGF) inhibitors, such as sunitinib, have been used as the primary targeted agents for patients with recurrent or distant metastasis of advanced renal cell carcinoma (RCC). However, endogenous or acquired sunitinib resistance has become a significant therapeutic problem. Therefore, we focused on mechanisms of sunitinib resistance in RCC. First, we undertook RNA sequencing analysis using previously established sunitinib-resistant RCC (SUR-Caki1, SUR-ACHN, and SUR-A498) cells. The results showed increased expression of secretogranin II (SCG2, chromogranin C) in SUR-RCC cells compared to parental cells. The Cancer Genome Atlas database showed that SCG2 expression was increased in RCC compared to normal renal cells. In addition, the survival rate of the SCG2 high-expression group was significantly lower than that of the RCC low-expression group. Thus, we investigated the involvement of SCG2 in sunitinib-resistant RCC. In vitro analysis showed that migratory and invasive abilities were suppressed by SCG2 knockdown SUR cells. As SCG2 was previously reported to be associated with angiogenesis, we undertook a tube formation assay. The results showed that suppression of SCG2 inhibited angiogenesis. Furthermore, coimmunoprecipitation assays revealed a direct interaction between SCG2 and hypoxia-inducible factor 1α (HIF1α). Expression levels of VEGF-A and VEGF-C downstream of HIF1α were found to be decreased in SCG2 knockdown SUR cells. In conclusion, SCG2 could be associated with sunitinib resistance through VEGF regulation in RCC cells. These findings could lead to a better understanding of the VHL/HIF/VEGF pathway and the development of new therapeutic strategies for sunitinib-resistant RCC.

RP11-367G18.1 V2 enhances clear cell renal cell carcinoma progression via induction of epithelial-mesenchymal transition

PURPOSE

Metastasis is the end stage of renal cell carcinoma (RCC), and clear cell renal cell carcinoma (ccRCC) is the most common malignant subtype. The hypoxic microenvironment is a common feature in ccRCC and plays an essential role in the regulation of epithelial-mesenchymal transition (EMT). Accumulating evidence manifests that long non-coding RNAs (lncRNAs) participate in RCC tumorigenesis and regulate hypoxia-induced EMT. Here, we identified a lncRNA RP11-367G18.1 induced by hypoxia, that was overexpressed in ccRCC tissues.

METHODS

A total of 216 specimens, including 149 ccRCC tumor samples and 67 related normal kidney parenchyma tissue samples, were collected. To investigate the biological fucntions of RP11.367G18.1 in ccRCC, migration, invasion, soft agar colony formation, xenograft tumorigenicity assays, and tail vein and orthotopic metastatic mouse models were performed. The relationship between RP11-367G18.1 and downstream signaling was analyzed utilizing reporter assay, RNA pull-down, chromatin immunopreciptation, and chromatin isolation by RNA purification assays.

RESULTS

Hypoxic conditions and overexpression of HIF-1α increased the level of RP11-367G18.1. RP11-367G18.1 induced EMT and enhanced cell migration and invasion through variant 2. Inhibition of RP11-367G18.1 variant 2 reversed hypoxia-induced EMT phenotypes. An in vivo study revealed that RP11-367G18.1 variant 2 was required for hypoxia-induced tumor growth and metastasis in ccRCC. Mechanistically, RP11-367G18.1 variant 2 interacted with p300 histone acetyltransferase to regulate lysine 16 acetylation on histone 4 (H4K16Ac), thus contributing to hypoxia-regulated gene expression. Clinically, RP11-367G18.1 variant 2 was upregulated in ccRCC tissues, particularly metastatic ccRCC tissues, and it is linked to poor overall survival.

CONCLUSION

These findings demonstrate the prognostic value and EMT-promoting role of RP11-367G18.1 and indicate that this lncRNA may provide a therapeutic target for ccRCC.

Kidney cancer biomarkers and targets for therapeutics: survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, p53, KRAS and AKT in renal cell carcinoma

The incidence of renal cell carcinoma (RCC) is increasing worldwide with an approximate 20% mortality rate. The challenge in RCC is the therapy-resistance. Cancer resistance to treatment employs multiple mechanisms due to cancer heterogeneity with multiple genetic and epigenetic alterations. These changes include aberrant overexpression of (1) anticancer cell death proteins (e.g., survivin/BIRC5), (2) DNA repair regulators (e.g., ERCC6) and (3) efflux pump proteins (e.g., ABCG2/BCRP); mutations and/or deregulation of key (4) oncogenes (e.g., MDM2, KRAS) and/or (5) tumor suppressor genes (e.g., TP5/p53); and (6) deregulation of redox-sensitive regulators (e.g., HIF, NRF2). Foci of tumor cells that have these genetic alterations and/or deregulation possess survival advantages and are selected for survival during treatment. We will review the significance of survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, TP5/p53, KRAS and AKT in treatment resistance as the potential therapeutic biomarkers and/or targets in RCC in parallel with our analized RCC-relevant TCGA genetic results from each of these gene/protein molecules. We then present our data to show the anticancer drug FL118 modulation of these protein targets and RCC cell/tumor growth. Finally, we include additional data to show a promising FL118 analogue (FL496) for treating the specialized type 2 papillary RCC.

Surgically induced ischemia has no impact on protein expression levels of HIF-1α and related biomarkers in renal cell carcinoma

The increasing demands for personalized targeted therapy directed against renal cell carcinoma have driven a search for predictive markers. Novel therapies targeting HIF-1α in renal cell carcinoma have been developed, and HIF-1α has been suggested as a novel predictive marker of response to therapy. The surgical resection of a kidney tumor induces tissue ischemia, and HIF-1α is an oxygen-sensitive transcription factor, which is known to be upregulated during hypoxia. This study investigated the impact of intra-surgical and post-surgical ischemia on protein expression levels of HIF-1α and three related biomarkers (VEGF, GLUT-1, and CAIX) in 20 patients with renal cell carcinoma with immunohistochemistry and Western blotting. Surgical ischemia did not have a significant impact on protein expression levels of any of the investigated markers. Long-post-surgical ischemia resulted in reduced expression levels of HIF-1α, probably due to autolysis. Our results suggest that HIF-1α is a stable protein, with expression levels not affected by intra-surgical ischemia, and hence, HIF-1α is suited for marker analysis.

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.

Biomarkers of Prognosis and Efficacy of Anti-angiogenic Therapy in Metastatic Clear Cell Renal Cancer

In the last decades, the prognosis of metastatic renal cell carcinoma (mRCC) has remarkably improved following the advent of the "targeted therapy" era. The expanding knowledge on the prominent role played by angiogenesis in RCC pathogenesis has led to approval of multiple anti-angiogenic agents such as sunitinib, pazopanib, axitinib, cabozantinib, sorafenib, and bevacizumab. These agents can induce radiological responses and delay cancer progression for months or years before onset of resistance, with a clinically meaningful activity. The need for markers of prognosis and efficacy of anti-angiogenic agents has become more compelling as novel systemic immunotherapy agents have also been approved in RCC and can be administered as an alternative to angiogenesis inhibitors. Anti PD-1 monoclonal antibody nivolumab has been approved in the second-line setting after tyrosine kinase inhibitors failure, while combination of nivolumab plus anti CTLA-4 monoclonal antibody ipilimumab has been approved as first-line therapy of RCC patients at intermediate or poor prognosis. In this review article, biomarkers of prognosis and efficacy of antiangiogenic therapies are summarized with a focus on those that have the potential to affect treatment decision-making in RCC. Biomarkers predictive of toxicity of anti-angiogenic agents have also been discussed.

Drug resistance in papillary RCC: from putative mechanisms to clinical practicalities

Papillary renal cell carcinoma (pRCC) is the second most common renal cell carcinoma (RCC) subtype and accounts for 10-15% of all RCCs. Despite clinical need, few pharmacogenomics studies in pRCC have been performed. Moreover, current research fails to adequately include pRCC laboratory models, such as the ACHN or Caki-2 pRCC cell lines. The molecular mechanisms involved in pRCC development and drug resistance are more diverse than in clear-cell RCC, in which inactivation of VHL occurs in the majority of tumours. Drug resistance to multiple therapies in pRCC occurs via genetic alteration (such as mutations resulting in abnormal receptor tyrosine kinase activation or RALBP1 inhibition), dysregulation of signalling pathways (such as GSK3β-EIF4EBP1, PI3K-AKT and the MAPK or interleukin signalling pathways), deregulation of cellular processes (such as resistance to apoptosis or epithelial-to-mesenchymal transition) and interactions between the cell and its environment (for example, through activation of matrix metalloproteinases). Improved understanding of resistance mechanisms will facilitate drug discovery and provide new effective therapies. Further studies on novel resistance biomarkers are needed to improve patient prognosis and stratification as well as drug development.

Anti-angiogenic efficacy of aflibercept and bevacizumab in primary oral squamous cell carcinoma cells

BACKGROUND

In recent decades, anti-angiogenic treatment strategy has been well described in cancer treatment. The anti-angiogenic activity of both bevacizumab and aflibercept has been researched on 10 previously established primary oral squamous cell carcinoma (OSCC) cells of an Iranian population with different levels of purity, in an attempt to find the most effective anti-angiogenic-targeted drug.

METHODS

To investigate and compare the effect of bevacizumab and aflibercept on vascular endothelial growth factor (VEGF) secretion of 10 primary OSCC cells, cell proliferation and viability were assessed by ELISA and MTT assays. In addition, cell migration was studied using scratch assay.

RESULTS

The results showed that VEGF impressively expressed in all primary cancer cells. Although both drugs significantly reduced the secretion of VEGF, the effect of aflibercept was more prominent. Also, bevacizumab-treated cells migration was lower than the control group and the cells treated with aflibercept showed the lowest migration rate compared to bevacizumab and control groups.

CONCLUSION

The anti-angiogenic-targeted drugs, especially Af, might be effective in treatment of patients with OSCC in combination with conventional surgical treatments.

HAF mediates the evasive resistance of anti-angiogenesis TKI through disrupting HIF-1α and HIF-2α balance in renal cell carcinoma

Anti-angiogenesis has emerged as a standard of care for metastatic renal cell carcinoma. However, long-lasting efficacy is seldom reached, and evasive resistance eventually occurs under anti-angiogenic tyrosine kinase inhibitor (TKI) therapy. To establish new therapeutic strategies, investigating the molecular mechanism of resistance is critically important. In our study, human umbilical vascular endothelial cells (HUVECs) were incubated with TKI treatment in conditioned medium derived from renal cancer cells (RCCs) to demonstrate cell viability. Quantitative real time PCR or Western blotting analysis detected the fluctuation of transcriptional factors HIF-1α and HIF-2α in RCCs under TKI treatment. We demonstrated the alteration of a specific cytokine produced from RCCs under normoxia or hypoxia incubation by utilizing a cytokine RT-PCR primer array. We found that the anti-angiogenic TKI sunitinib disrupted the balance between HIF-1α and HIF-2α in RCCs and led to a protective effect on HUVECs against sunitinib treatment when cultured with conditioned medium. Mechanistically, RCCs treated with sunitinib resulted in down-regulation of HIF-1α, but not HIF-2α, through reduction of both mRNA and protein levels. The down-regulation of HIF-1α by sunitinib occurred via hypoxia associated factor (HAF), which also enhanced HIF-2α transactivation activity to increase the production of pro-angiogenic factors and cytokines and promote HUVEC proliferation. This phenomenon was observed in ACHN and A498 cells, which express both HIF-1α and HIF-2α, but was not observed in 786-O cells, which express only HIF-2α. Our results illustrated that targeting both angiogenesis and hypoxia pathways might provide a resolution to dealing with the devastating effects of anti-angiogenesis resistance.

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.

Axitinib after Sunitinib in Metastatic Renal Cancer: Preliminary Results from Italian "Real-World" SAX Study

Axitinib is an oral angiogenesis inhibitor, currently approved for treatment of metastatic renal cell carcinoma (mRCC) after failure of prior treatment with Sunitinib or cytokine. The present study is an Italian Multi-Institutional Retrospective Analysis that evaluated the outcomes of Axitinib, in second-line treatment of mRCC. The medical records of 62 patients treated with Axitinib, were retrospectively reviewed. The Progression Free Survival (PFS), the Overall Survival (OS), the Objective Response Rate (ORR), the Disease Control Rate (DCR), and the safety profile of axitinib and sunitinib–axitinib sequence, were the primary endpoint. The mPFS was 5.83 months (95% CI 3.93–7.73 months). When patients was stratified by Heng score, mPFS was 5.73, 5.83, 10.03 months according to poor, intermediate, and favorable risk group, respectively. The mOS from the start of axitinib was 13.3 months (95% CI 8.6–17.9 months); the observed ORR and DCR were 25 and 71%, respectively. When stratified patients by subgroups defined by duration of prior therapy with Sunitinib (≤ vs. >median duration), there was a statistically significant difference in mPFS with 8.9 (95% CI 4.39–13.40 months) vs. 5.46 months (95% CI 4.04–6.88 months) for patients with a median duration of Sunitinib >13.2 months. DCR and ORR to previous Sunitinib treatment was associated with longer statistically mPFS, 7.23 (95% CI 3.95–10.51 months, p = 0.01) and 8.67 (95% CI 4.0–13.33 months, p = 0.008) vs. 2.97 (95% CI 0.65–5.27 months, p = 0.01) and 2.97 months (95% CI 0.66–5.28 months, p = 0.01), respectively. Overall Axitinib at standard schedule of 5 mg bid, was well-tolerated. The most common adverse events of all grades were fatig (25.6%), hypertension (22.6%), gastro-intestinal disorders (25.9%), and hypothyroidism (16.1%). The sequence Sunitinib–Axitinib was well-tolerated without worsening in side effects, with a median OS of 34.7 months (95% CI 18.4–51.0 months). Our results are consistent with the available literature; this retrospective analysis confirms that Axitinib is effective and safe in routine clinical practice.

Recent aspects of sunitinib therapy in patients with metastatic clear-cell renal cell carcinoma: a systematic review of the literature

Sunitinib is an orally available inhibitor of multiple tyrosine-kinase receptors approved for the treatment of advanced clear-cell renal cell carcinoma (ccRCC), a disease which has habitually had a very poor patient survival rate. Although it has become the most widely used drug for this disease, it remains not completely clear the best treatment strategy with these agent. The aim of this review is to highlight the most recent and interesting aspects of the research on treatment of advanced ccRCC with sunitinib and eventually determine alternative treatment schedule to reduce the incidence of side effects; we also wanted to review recent biomarkers able to predict response to therapy and also to point out the mechanism of acquired resistance to this drug.

Correlation between BOLD-MRI and HIF expression level in renal carcinoma

Occupying about 2%~3% of all malignant tumors, renal carcinoma is the most common primary cancer in kidney. The oxidative level of tumor cells is of vital role for optimizing treatment plan, evaluating efficacy and predicting prognosis. This study thus investigated the R2(*) value in mouse renal carcinoma model and the correlation between tumor hypoxia and expression level of hypoxia inducible factor-1 (HIF-1). A total of 20 BALB/C nude mice (4~6 weeks old) were inoculated with human ACHN renal carcinoma cells to generate renal cancer model. After the tumor diameter reached 0.5 cm, all animals were examined by BOLD-MRI, both under normal inhalation (R2a(*)) and carbogen treatment (R2b(*)). The alternation of R2(*) values (ΔR2(*)=R2a(*) - R2b(*)) was calculated. Mice were then sacrificed for Immunohistochemical (IHC) staining targeting HIF-1α and HIF-2α. The positive score of HIF was then analyzed for its correlation with R2(*) value. In 18 mice finished both experiments, Pearson correlation analysis revealed significant negative correlation between R2a(*) and ΔR2(*) (r=-0.48, P<0.05) and positive relationship between ΔR2(*) and HIF-2α (r=0.38, P<0.05). HIF-1α level, however, did not correlated with tumor R(*) values. The positive correlation between ΔR2(*) and HIF-2α, but not HIF-1α, suggested potential role of combined BOLD-MRI technique and HIF-1α staining in clinical diagnosis of renal carcinoma. HIF-2α may work as biological marker for renal cancer.

Mammalian Target of Rapamycin Inhibitors Resistance Mechanisms in Clear Cell Renal Cell Carcinoma

Mammalian target of rapamycin (mTOR) is a kinase protein involved in PI3K/AKT signaling with a central role in the processes of cell growth, survival and angiogenesis. Frequent mutations of this pathway make upstream and downstream components novel targets for tailored therapy design. Two mTOR inhibitors - everolimus and temsirolimus - enable an increase in overall survival (OS) or progression-free survival (PFS) time in a treatment of renal cancer. Despite recent advances in renal cancer treatment, resistance to targeted therapy is common. Understanding of molecular mechanisms is the basis of drug resistance which can facilitate prediction of success or failure in combinational or sequential targeted therapy. The article provides current knowledge on the mTOR signaling network and gives insight into the mechanisms of resistance to mTOR inhibitors from the complex perspective of RCC biology. The mechanisms of resistance developed not only by cancer cells, but also by interactions with tumor microenvironment are analyzed to emphasize the role of angiogenesis in ccRCC pathogenesis. As recent studies have shown the role of PI3K/AKT-mTOR pathway in proliferation and differentiation of cancer stem cells, we discuss cancer stem cell hypothesis and its possible contribution to ccRCC resistance. In the context of drug resistance, we also elaborate on a new approach considering ccRCC as a metabolic disease. In conclusion we speculate on future developments in agents targeting the mTOR pathway taking into consideration the singular biology of ccRCC.

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.

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.

The current status of tailor-made medicine with molecular biomarkers for patients with clear cell renal cell carcinoma

Appropriate use of multiple reliable molecular biomarkers in the right context will play a role in tailormade medicine of clear cell renal cell carcinoma (RCC) patients in the future. A total of 11,056 patients from 53 studies were included in this review. The article numbers of the each evidence levels, using the grading system defined by the Oxford Centre for Evidence-based Medicine, in 1b, 2a, 2b, and 3b were 5 (9%), 18 (34%), 29 (55%), and 1 (2%), respectively. The main goal of using biomarkers is to refine predictions of tumor progression, pharmacotherapy responsiveness, and cancer-specific and/or overall survival. Currently, carbonic anhydrase (CA9) and vascular endothelial growth factor (VEGF) in peripheral blood and p53 in tumor tissues are measured to predict metastasis, while VEGF-related proteins in peripheral blood are used to assess pharmacotherapy responsiveness with sunitinib. Furthermore, interleukin 8, osteopontin, hepatocyte growth factor, and tissue inhibitors of metalloproteinases-1 in peripheral blood enable assessment of responsiveness to pazopanib treatment. Other reliable molecular biomarkers include von Hippel–Lindau gene alteration, hypoxia-inducible factor-1a, CA9, and survivin in tumor tissues and VEGF in peripheral blood for predicting cancer-specific survival. In the future, studies should undergo external validation for developing tailored management of clear cell RCC with molecular biomarkers, since individual institutional studies lack the generalization and consistency required to maintain accuracy among different patient series.

HAVCR/KIM-1 activates the IL-6/STAT-3 pathway in clear cell renal cell carcinoma and determines tumor progression and patient outcome

Renal cell carcinoma (RCC), the third most prevalent urological cancer, claims more than 100,000 lives/year worldwide. The clear cell variant (ccRCC) is the most common and aggressive subtype of this disease. While commonly asymptomatic, more than 30% of ccRCC are diagnosed when already metastatic, resulting in a 95% mortality rate. Notably, nearly one-third of organ-confined cancers treated by nephrectomy develop metastasis during follow-up care. At present, diagnostic and prognostic biomarkers to screen, diagnose, and monitor renal cancers are clearly needed. The gene encoding the cell surface molecule HAVCR1/KIM-1 is a suggested susceptibility gene for ccRCC and ectodomain shedding of this molecule may be a predictive biomarker of tumor progression. Microarray analysis of 769-P ccRCC-derived cells where HAVCR/KIM-1 levels have been upregulated or silenced revealed relevant HAVCR/KIM-1-related targets, some of which were further analyzed in a cohort of 98 ccRCC patients with 100 month follow-up. We found that HAVCR/KIM-1 activates the IL-6/STAT-3/HIF-1A axis in ccRCC-derived cell lines, which depends on HAVCR/KIM-1 shedding. Moreover, we found that pSTAT-3 S727 levels represented an independent prognostic factor for ccRCC patients. Our results suggest that HAVCR/KIM-1 upregulation in tumors might represent a novel mechanism to activate tumor growth and angiogenesis and that pSTAT-3 S727 is an independent prognostic factor for ccRCC.

Circulating proteins as potential biomarkers of sunitinib and interferon-α efficacy in treatment-naïve patients with metastatic renal cell carcinoma

PURPOSE

We investigated potential biomarkers of efficacy in a phase III trial of sunitinib versus interferon-alpha (IFN-α), first-line in metastatic renal cell carcinoma (mRCC), by analyzing plasma levels of vascular endothelial growth factor (VEGF)-A, VEGF-C, soluble VEGF receptor-3 (sVEGFR-3) and interleukin (IL)-8.

METHODS

Seven hundred and fifty mRCC patients were randomized to oral sunitinib 50 mg/day in repeated cycles of a 4-week on/2-week off schedule or IFN-α 9 million units subcutaneously thrice weekly. Plasma samples collected from a subset of 63 patients on days 1 and 28 of cycles 1-4 and at end of treatment were analyzed by ELISA.

RESULTS

Baseline characteristics of biomarker-evaluated patients in sunitinib (N = 33) and IFN-α (N = 30) arms were comparable to their respective intent-to-treat populations. By univariate Cox regression analysis, low baseline soluble protein levels were associated with lower risk of progression/death (all P < 0.05): in both treatment arms, baseline VEGF-A and IL-8 were associated with overall survival (OS) and baseline VEGF-C with progression-free survival (PFS); in the sunitinib arm, baseline VEGF-A was associated with PFS and baseline sVEGFR-3 with PFS and OS; in the IFN-α arm, baseline IL-8 was associated with PFS. In multivariate analysis, baseline sVEGFR-3 and IL-8 remained independent predictors of OS in the sunitinib arm, while no independent predictors of outcome remained in the IFN-α arm. Pharmacodynamic changes were not associated with PFS or OS for any plasma protein investigated.

CONCLUSIONS

Our findings suggest that, in mRCC, baseline VEGF-A and IL-8 may have prognostic value, while baseline sVEGFR-3 may predict sunitinib efficacy.

Correlation of vascular endothelial growth factor and hypoxia-inducible factor-1α expression with pathological renal artery changes in patients with renal cell carcinoma

OBJECTIVE

The aim of this study was to correlate the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) with pathological renal artery changes in patients with renal cell carcinoma (RCC). A further aim was to correlate intratumoral microvessel density (MVD) with VEGF and HIF-1α expression and prognostic factors for RCC, including tumour necrosis.

MATERIAL AND METHODS

Formalin-fixed and paraffin-embedded tissue blocks from 150 patients with RCC and 50 patients with non-tumorous kidney diseases were analysed. The control group consisted of specimens from both renal arteries obtained from 25 decedents at routine autopsy (50 cases in total). Immunohistochemistry was performed using primary antibodies to VEGF, HIF-1α and CD31.

RESULTS

Pathological renal artery changes were more common in patients with RCC and non-tumorous kidney diseases than in the control group. MVD was higher in the RCCs of patients with pathological renal artery changes. Tumours with higher HIF-1α expression had higher MVD; however, VEGF expression was not associated with MVD. A significant association was also found between MVD and the extent of tumour necrosis, in that less necrotic tumours had higher MVD. No association between renal artery changes and VEGF and HIF-1α expression was established.

CONCLUSION

Considering the results of this study, the evaluation of renal artery changes in forthcoming research on RCC would be helpful for several reasons: to estimate their incidence in a larger number of patients, to clarify their connection with RCC and to reveal their relationship with MVD in RCC.

Hypoxia-induced factor-1 alpha upregulates vascular endothelial growth factor C to promote lymphangiogenesis and angiogenesis in breast cancer patients

Hypoxia-induced factor-1 alpha (HIF-1α) affects many effector molecules and regulates tumor lymphangiogenesis and angiogenesis during hypoxia. The aim of this study was to investigate the role of HIF-1α in the regulation of vascular endothelial growth factor C (VEGF-C) expression and its effect on lymphangiogenesis and angiogenesis in breast cancer. Lymphatic vessel density (LVD), microvessel density (MVD) and the expressions of HIF-1α and VEGF-C proteins were evaluated by immunohistochemistry in 75 breast cancer samples. There was a significant correlation between HIF-1α and VEGF-C (P = 0.014, r = 0.273, Spearman's coefficient of correlation). HIF-1α and VEGF-C overexpression was significantly correlated with higher LVD (P = 0.003 and P = 0.017, respectively), regional lymph nodal involvement (P = 0.002 and P = 0.004, respectively) and advanced tumor, node, metastasis (TNM) classification (P = 0.001 and P = 0.01, respectively). Higher MVD was observed in the group expressing higher levels of HIF-1α and VEGF-C (P = 0.033 and P = 0.037, respectively). Univariate analysis showed shorter survival time in patients expressing higher levels of HIF-1α and VEGF-C. HIF-1α was also found to be an independent prognostic factor of overall survival in multivariate analysis. The results suggest that HIF-1α may affect VEGF-C expression, thus acting as a crucial regulator of lymphangiogenesis and angiogenesis in breast cancer. This study highlights promising potential of HIF-1α as a therapeutic target against tumor lymph node metastasis.

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.

The expression of Eg5 predicts a poor outcome for patients with renal cell carcinoma

Eg5 is a member of the kinesin family of proteins, which associates with bipolar spindle formation in dividing tumor cells during mitosis. The aim of our study is to investigate the prognostic role of Eg5 expression in patients with renal cell carcinoma (RCC). RCC tissue specimens from 164 consecutively treated patients who underwent surgery between 2005 and 2011 were evaluated. The Eg5 expression was determined by immunohistochemistry, and correlated with clinicopathological parameters. The prognostic significance of Eg5 expression was explored using the univariate and multivariate survival analysis of 164 patients who were followed; one hundred and sixty-four tissue specimens "of patients" who were regularly followed with the mean 35.8 months (from 5 to 80 months). The expression of Eg5 was significantly associated with tumor nuclear grade (P = 0.019) and stage (P = 0.007), as well as tumor size (P = 0.033). In univariate analysis, Eg5 overexpression showed unfavorable influence on recurrence-free survival with statistical significance (P = 0.003). Clinical stage, nuclear grade and tumor size also showed strong statistical relation with adverse recurrence-free survival (P < 0.001). Multivariate analysis revealed that tumor stage, nuclear grade and Eg5 reactivity (P < 0.001, P = 0.002, P = 0.032) were identified as independent prognostic factors for recurrence-free survival in patients with RCC. In our opinion, the result of this study proved the relationship between Eg5 expression and worse clinical outcome in RCC. This finding suggested that Eg5 served as a prognostic factor, which could be useful to predict cancer evolution and provide appropriate treatments for RCC patients.

Preoperatively evaluating the correlation between pathological grades and blood oxygenation level-dependent MRI in clear cell renal cell carcinomas

RATIONALE AND OBJECTIVES

To assess whether r(2)* values can be used to determine the nuclear grade of clear cell renal cell carcinomas (CRCC).

MATERIALS AND METHODS

A total of 26 patients with pathologically proven CRCCs underwent blood oxygen level-dependent magnetic resonance imaging. r(2)* values were determined for the solid components of CRCC lesions. Histological nuclear grade was determined for each lesion. All patients were divided into low- and high-grade groups. r(2)* values were compared between different grades and between low- and high- grade groups. Receiver operating characteristic curve was drawn to establish the cutoff point for r(2)* values. The correlation between r(2)* values and pathological groups was assessed.

RESULTS

Low-grade group (grades I + II) contained 17 cases and high-grade group (grades III + IV) contained nine cases. The intraclass correlation coefficient for r(2)* values was 0.89. Significant difference was seen between different grades (P < .005). r(2)* values of the high-grade group were higher than the low-grade group (P < .005). A sensitivity of 78% and a specificity of 100% were achieved with a cutoff of 31.87 seconds(-1). r(2)* values directly correlated with pathological groups (P < .005).

CONCLUSION

r(2)* values of CRCCs could be employed as a noninvasive biomarker to help classify the nuclear grade of CRCC.

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.

Reduced expression of vasohibin-1 is associated with clinicopathological features in renal cell carcinoma

Vasohibin-1(VASH1) has recently been isolated as a novel negative feedback inhibitor of angiogenesis. Several studies have demonstrated that VASH1 plays important roles in tumor angiogenesis but the role of this angiogenic inhibitor in renal cell carcinoma (RCC) has not been elucidated until now. In this study, we investigated the expression pattern of VASH1 and the association with clinicopathological features in RCC. Expression of VASH1, hypoxia-inducible factor-1α (HIF-1α), and microvessel density (MVD, labeled by CD34) was assessed by immunohistochemistry in 46 RCC specimens and 20 adjacent nontumorous renal tissues (ANRTs). Correlation between vasohibin-1 and HIF-1α, MVD, and clinicopathological features was then investigated. In RCC, VASH1 was expressed mainly in the cytoplasm and membrane of tumor cells and partly in vascular endothelial cells. In ANRT, it was mainly expressed in the cytoplasm and membrane of renal tubular epithelial cells and partly in vascular endothelial cells and glomerular mesangial cells. The expression level of VASH1 in RCC tissue was significantly lower than that in ANRT and was significantly reduced with the increased degree of malignancy in RCC tissues. In addition, a significantly negative correlation was noted between VASH1 expression and HIF-1α expression and a significantly negative correlation was noted between VASH1 expression and MVD in RCC. Therefore, VASH1 expression is reduced and it associates with clinicopathological features in RCC. Based on our findings and the knowledge of other angiogenesis inhibitors, we postulate that VASH1 would potentially be a biomarker and a candidate for molecular targeted therapy for patients with RCC in the future.

Current and future systemic treatments for renal cell carcinoma

Systemic treatment of renal cell carcinoma has changed dramatically since 2007, with the development and approval of six new agents, which target complex molecular pathways regulating tumour angiogenesis and cell proliferation and survival. These treatments have significantly improved survival times in metastatic renal cell carcinoma, but remain palliative. A number of newer agents are in clinical development, which offer theoretical advantages over existing treatments, and research methodologies are adapting with the aim of defining an individualised approach to therapy which exploits the underlying tumour biology. This review will provide an overview of current and emerging systemic treatments and how they might be integrated with surgical therapy, with a particular focus on advanced, clear cell metastatic renal cell carcinoma.

From tumor hypoxia to cancer progression: the implications of hypoxia-inducible factor-1 expression in cancers

Hypoxia, defined as a decrease of tissue oxygen levels, represents a fundamental pathophysiological condition in the microenvironment of solid tumors. Tumor hypoxia is known to be associated with radio/chemo-resistance and metastasis that eventually lead to cancer progression contributing to poor prognosis in cancer patients. Among transcription factors that accumulated under hypoxic conditions, hypoxia-inducible factor-1 (HIF-1) is a master transcription factor that has received the most intense attention in this field of research due to its capacity to modulate several hundred genes. With a clearer understanding of the HIF-1 pathway, efforts are directed at manipulation of this complex genetic process in order to ultimately decrease cellular HIF-1 levels. Some novel agents have been shown to have HIF-1 inhibition activity through a variety of molecular mechanisms and have provided promising results in the preclinical setting.

Correlations between SUVmax and expression of GLUT1 and growth factors inducing lymphangiogenesis

RATIONALE AND OBJECTIVES

The purpose of this study was to assess the correlations between the maximum standardized uptake value (SUVmax) of colorectal carcinoma and hepatocyte growth factor (HGF), vascular endothelial growth factor C (VEGF-C), and their respective receptors using (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT).

METHODS

Fluorine-18-FDG PET/CT scans were performed on 33 patients with colorectal carcinoma before any treatment. The SUVmax of colorectal carcinoma and the clinicopathologic data associated with lymphatic metastases were analyzed. The expression of glucose transporter 1 (GLUT1), HGF, c-Met, VEGF-C, and vascular endothelial growth factor receptor 3 (VEGFR-3) in tumor tissues was analyzed using immunohistochemical methods. Lymphatic endothelial cells were marked with D2-40, and lymphatic vessel density (LVD) was recorded. The correlations were analyzed among the SUVmax of colorectal carcinoma, LVD, and the expression of GLUT1, HGF, c-Met, VEGF-C, and VEGFR-3 in tumor tissues.

RESULTS

SUVmax and LVD in 15 patients with lymphatic metastases were 13.00 ± 4.51 and 6.25 ± 1.54, respectively, whereas in 18 patients with nonmetastatic nodes, SUVmax and LVD were 9.66 ± 4.82 and 4.54 ± 1.02, respectively. The differences of SUVmax and LVD between metastatic and nonmetastatic patients were statistically significant (F = 4.153, P = .025, and F = 14.501, P = .001, respectively). There were no statistical differences of SUVmax and LVD in variably differentiated colorectal carcinoma (F = 0.708, P = .502, and F = 0.311, P = .735, respectively). The expression rates of GLUT1 in neoplastic and normal tissue were 72.7% (24 of 33) and 21.2% (seven of 33), respectively (P = .001). Moreover, the expression rates of GLUT1 in metastatic and nonmetastatic tissue were 93.33% (14 of 15) and 61.11% (11 of 18), respectively (P = .038). LVD and the integrated optical density of GLUT1 were 5.31 ± 1.53 and 8.21 × 10(4) ± 4.30 × 10(4), respectively, in tumor tissue, and there were linear correlations between SUVmax and LVD (r = 0.373, P = .033) and between SUVmax and expression of GLUT1 (r = 0.428, P = .013). The differences of SUVmax in HGF, c-Met, and VEGF-C groups with different expressions were statistically significant (P = .007, P = .009, and P = .030, respectively). No correlation was found between the expression of VEGFR-3 and SUVmax. The expression of GLUT1 and HGF as well as of GLUT1 and VEGF-C was rank correlated (r = 0.521, P = .002, and r = 0.505, P = .003, respectively). No rank correlations were found between the expression of GLUT1 and c-Met, GLUT1, and VEGFR-3.

CONCLUSIONS

The SUVmax of colorectal carcinoma was significantly higher in metastatic patients; the uptake of colorectal carcinoma was associated with LVD and the expression of HGF and VEGF-C but not with the expression of VEGFR-3.

Delivering preventive, predictive and personalised cancer medicine for renal cell carcinoma: the challenge of tumour heterogeneity

Recent years have seen major advances in the management of metastatic renal cell carcinoma (mRCC). The tyrosine kinase and mammalian target of rapamycin inhibitors have resulted in disease control and improved survival for many patients with mRCC, but they have not led to preventive, predictive or personalised medicine (PPPM). Failure to achieve this rests ultimately with inadequate knowledge of tissue and molecular heterogeneity; discovery of these drugs was based upon identification of pathogenic molecular pathways in RCC, but research into molecular factors which underpin drug response, resistance and selection of therapy for individual patients has lagged well behind clinical trials of drug development. This review will provide an overview of the development of targeted drug therapies for mRCC, will discuss the challenges which currently impede the delivery of PPPM, including identification of biomarkers, drug resistance and molecular heterogeneity, and will propose research methodologies and technologies required to overcome these obstacles.

Clinical and molecular prognostic factors in renal cell carcinoma: what we know so far

The current treatment paradigm for metastatic renal cell carcinoma (RCC) includes agents that target the vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) pathways. Because these agents have revolutionized RCC over the past five years, new clinical and molecular predictive and prognostic tools are required. These are potentially important for therapy selection, patient counseling, and clinical trial stratification. This review examines clinical prognostic models and molecular biomarkers in RCC.

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.

Tumor-initiating cells and tumor vascularization

Tumor-initiating cells (TICs) with stem-like cell properties initiate and sustain progressive growth, resulting in a heterogeneous tumor mass. The survival and growth of tumors rely on the development of a vasculature to provide nutrients and oxygen. Crosstalk between TICs and vascularization may be one of the central players in the initiation, long-term maintenance, and progression of tumors. This review surveys current evidence concerning the crosstalk that occurs in tumor/stromal interactions, including genetic change, vascular niche, hypoxia, and dormancy of tumors. A better understanding of this crosstalk might help provide the basis for developing more effective therapeutic drug targets.

Hypoxia-inducible factor-1α protein expression is associated with poor survival in normal karyotype adult acute myeloid leukemia

We examined the predictive impact of HIF-1α protein expression on clinical outcome of 84 normal karyotype acute myeloid leukemia (NK-AML) patients (median age 66.5 years) at our institute. Thirty percent of NK-AML cells expressed cytoplasmic HIF-1α. In univariate analysis, low HIF-1α (≤ 5%, n = 66) was associated with improved event-free survival (p = 0.0453, HR = 0.22). Multivariate analysis incorporating age, complete remission, FLT3-ITD mutation, and marrow blast percentage demonstrated that HIF-1α was independently associated with poorer overall and event-free survival. HIF-1α expression correlated with VEGF-C but not VEGF-A, marrow angiogenesis, FLT3 ITD or NPM1 mutations. These results support HIF-1α as an outcome marker for NK-AML.

Biomarkers in renal cell carcinoma

PURPOSE OF REVIEW

To review the latest information on biomarkers in renal cell carcinoma and their use in integrated staging systems.

RECENT FINDINGS

The discovery of the Von Hippel-Lindau defect and the hypoxia inducible factor-1alpha transcripted genes has led to an explosion in the understanding of molecular pathways in renal cell carcinoma. The two most prominent biomarkers are carbonic anhydrase IX and vascular endothelial-derived growth factor. Carbonic anhydrase IX has demonstrated excellent specificity and ability to predict treatment response. Vascular-derived growth factor has good correlation with stage, grade and increased levels with adverse survival. Markers such as CXCL16, ADAM10, B7-H1, Ki-67, survivin, P53, GLUT-1, calveolin-1 and endoglin are continuously being validated. CXCL16 is one of the newest biomarkers, is significantly expressed in papillary renal cell carcinoma and is an independent prognostic marker for better patient survival. The incorporation of biomarkers into integrated staging systems such as UCLA Integrated Staging System, SSIGN and Bioscore are discussed and compared.

SUMMARY

The use of novel molecular biomarkers are being incorporated into clinical practice. The understanding of molecular pathways will lead to tailored treatment to the individual patient.