Jyoti Nanda

NO-sulindac inhibits the hypoxia response of PC-3 prostate cancer cells via the Akt signalling pathway

Nitric oxide‐donating non‐steroidal anti‐inflammatory drugs are safer than traditional NSAIDs and inhibit the growth of prostate cancer cells with greater potency than NSAIDs. In vivo, prostate cancer deposits are found in a hypoxic environment which induces resistance to chemotherapy. The aim of this study was to assess the effects and mechanism of action of a NO‐NSAID called NO‐sulindac on the PC‐3 prostate cancer cell line under hypoxic conditions. NO‐sulindac was found to have pro‐apoptotic, cytotoxic, and anti‐invasive effect on PC‐3 cells under normoxia and hypoxia. NO‐sulindac was significantly more cytotoxic than sulindac at all oxygen levels. The sulindac/linker and NO‐releasing subunits both contributed to the cytotoxic effects of NO‐sulindac. Resistance of PC‐3 cells to NO‐sulindac was induced as the oxygen concentration declined. Hypoxia‐induced chemoresistance was reversed by knocking‐down hypoxia‐inducible factor‐1α (HIF‐1α) mRNA using RNAi. Nuclear HIF‐1α levels were upregulated at 0.2% oxygen but reduced by treatment with NO‐sulindac, as was Akt phosphorylation. NO‐sulindac treatment of hypoxic PC‐3 cells transfected with a reporter construct, downregulated activation of the hypoxia response element (HRE) promoter. Co‐transfection of PC‐3 cells with the HRE promoter reporter construct and myr‐Akt (constitutively active Akt) plasmids reversed the NO‐sulindac induced reduction in HRE activation. Real‐time polymerase chain reaction analysis of hypoxic, NO‐sulindac treated PC‐3 cells showed downregulation of lysyl oxidase and carbonic anhydrase IX mRNA expression. Collectively, these novel findings demonstrate that NO‐sulindac directly inhibits the hypoxia response of PC‐3 prostate cancer cells by inhibiting HIF‐1α translation via the Akt signalling pathway. The ability of NO‐sulindac to inhibit tumour adaption to hypoxia has considerable relevance to the future management of prostate cancer with the same cellular properties as PC‐3.

DNA strand breaks and hypoxia response inhibition mediate the radiosensitisation effect of nitric oxide donors on prostate cancer under varying oxygen conditions

Prostate cancer cells can exist in a hypoxic microenvironment, causing radioresistance. Nitric oxide (NO) is a radiosensitiser of mammalian cells. NO-NSAIDs are a potential means of delivering NO to prostate cancer cells. This study aimed to determine the effect and mechanism of action of NO-sulindac and radiation, on prostate cancer cells and stroma, under normoxia (21% oxygen) and chronic hypoxia (0.2% oxygen). Using clonogenic assays, at a surviving fraction of 10% the sensitisation enhancement ratios of radiation plus NO-sulindac over radiation alone on PC-3 cells were 1.22 and 1.42 under normoxia and hypoxia, respectively. 3D culture of PC-3 cells revealed significantly reduced sphere diameter in irradiated spheres treated with NO-sulindac. Neither NO-sulindac nor sulindac radiosensitised prostate stromal cells under normoxia or hypoxia. HIF-1α protein levels were reduced by NO-sulindac exposure and radiation at 21 and 0.2% oxygen. Alkaline Comet assay analysis suggested an increased rate of single strand DNA breaks and slower repair of these lesions in PC-3 cells treated with NO-sulindac prior to irradiation. There was a higher level of γ-H2AX production and hence double strand DNA breaks following irradiation of NO-sulindac treated PC-3 cells. At all radiation doses and oxygen levels tested, treatment of 2D and 3D cultures of PC-3 cells with NO-sulindac prior to irradiation radiosensitised PC-3, with minimal effect on stromal cells. Hypoxia response inhibition and increased DNA double strand breaks are potential mechanisms of action. Neoadjuvent and concurrent use of NO-NSAIDs have the potential to improve radiotherapy treatment of prostate cancer under normoxia and hypoxia.

Oestrogen and benign prostatic hyperplasia: effects on stromal cell proliferation and local formation from androgen

Oestrogens have been implicated as a cause of benign prostatic hyperplasia (BPH). Previous animal studies led to the hypothesis that oestrogens can stimulate prostate growth, resulting in hyperplasia of the gland. In humans, the precise role of oestrogens in BPH pathogenesis is currently unclear. We investigated the direct effects of oestradiol on the proliferation of BPH-derived prostate cells in culture. Oestradiol (10(-7) and 10(-6) M) moderately increased the proliferation of stromal cells in culture; this stimulation was antagonised by anti-oestrogen ICI 182 780, indicating an oestrogen receptor (ER)-mediated mechanism. By contrast, oestradiol had no effects on the proliferation of epithelial cells in culture. Parameters that can determine the response of stromal cells to oestrogens, including expression of the two ER subtypes and aromatase activity, were investigated. ER beta expression in stromal cells in culture was demonstrated by immunohistochemistry and western blot analysis, and was confirmed by semi-quantitative RT-PCR showing higher expression of ER beta than ER alpha mRNA in stromal cells. Aromatase, the enzyme that converts androgen precursors to oestrogens, was also examined. Aromatase mRNA and activity were detected in stromal, but not epithelial cells in culture, suggesting a mechanism whereby oestrogen concentrations can be regulated in the BPH stroma. Taken together, these findings support the hypothesis that oestrogens play a role in the pathogenesis of BPH, a disease characterised predominantly by stromal overgrowth.

Differential Expression of Prognostic Proteomic Markers in Primary Tumour, Venous Tumour Thrombus and Metastatic Renal Cell Cancer Tissue and Correlation with Patient Outcome

Renal cell carcinoma (RCC) is the most deadly of urological malignancies. Metastatic disease affects one third of patients at diagnosis with a further third developing metastatic disease after extirpative surgery. Heterogeneity in the clinical course ensures predicting metastasis is notoriously difficult, despite the routine use of prognostic clinico-pathological parameters in risk stratification. With greater understanding of pathways involved in disease pathogenesis, a number of biomarkers have been shown to have prognostic significance, including Ki67, p53, vascular endothelial growth factor receptor 1 (VEGFR1) and ligand D (VEGFD), SNAIL and SLUG. Previous pathway analysis has been from study of the primary tumour, with little attention to the metastatic tumours which are the focus of targeted molecular therapies. As such, in this study a tissue microarray from 177 patients with primary renal tumour, renal vein tumour thrombus and/or RCC metastasis has been created and used with Automated Quantitative Analysis (AQUA) of immunofluorescence to study the prognostic significance of these markers in locally advanced and metastatic disease. Furthermore, this has allowed assessment of differential protein expression between the primary tumours, renal vein tumour thrombi and metastases. The results demonstrate that clinico-pathological parameters remain the most significant predictors of cancer specific survival; however, high VEGFR1 or VEGFD can predict poor cancer specific survival on univariate analysis for locally advanced and metastatic disease. There was significantly greater expression of Ki67, p53, VEGFR1, SLUG and SNAIL in the metastases compared with the primary tumours and renal vein tumour thrombi. With the exception of p53, these differences in protein expression have not been shown previously in RCC. This confirms the importance of proliferation, angiogenesis and epithelial to mesenchymal transition in the pathogenesis and metastasis of RCC. Importantly, this work highlights the need for further pathway analysis of metastatic tumours for overcoming drug resistance and developing new therapies.

Carbonic Anhydrase 9 Expression Increases with Vascular Endothelial Growth Factor–Targeted Therapy and Is Predictive of Outcome in Metastatic Clear Cell Renal Cancer

Background There is a lack of biomarkers to predict outcome with targeted therapy in metastatic clear cell renal cancer (mccRCC). This may be because dynamic molecular changes occur with therapy. Objective To explore if dynamic, targeted-therapy-driven molecular changes correlate with mccRCC outcome. Design, setting, and participants Multiple frozen samples from primary tumours were taken from sunitinib-naïve (n = 22) and sunitinib-treated mccRCC patients (n = 23) for protein analysis. A cohort (n = 86) of paired, untreated and sunitinib/pazopanib-treated mccRCC samples was used for validation. Array comparative genomic hybridisation (CGH) analysis and RNA interference (RNAi) was used to support the findings. Intervention Three cycles of sunitinib 50 mg (4 wk on, 2 wk off). Outcome measurements and statistical analysis Reverse phase protein arrays (training set) and immunofluorescence automated quantitative analysis (validation set) assessed protein expression. Results and limitations Differential expression between sunitinib-naïve and treated samples was seen in 30 of 55 proteins (p < 0.05 for each). The proteins B-cell CLL/lymphoma 2 (BCL2), mutL homolog 1 (MLH1), carbonic anhydrase 9 (CA9), and mechanistic target of rapamycin (mTOR) (serine/threonine kinase) had both increased intratumoural variance and significant differential expression with therapy. The validation cohort confirmed increased CA9 expression with therapy. Multivariate analysis showed high CA9 expression after treatment was associated with longer survival (hazard ratio: 0.48; 95% confidence interval, 0.26–0.87; p = 0.02). Array CGH profiles revealed sunitinib was associated with significant CA9 region loss. RNAi CA9 silencing in two cell lines inhibited the antiproliferative effects of sunitinib. Shortcomings of the study include selection of a specific protein for analysis, and the specific time points at which the treated tissue was analysed. Conclusions CA9 levels increase with targeted therapy in mccRCC. Lower CA9 levels are associated with a poor prognosis and possible resistance, as indicated by the validation cohort. Patient summary Drug treatment of advanced kidney cancer alters molecular markers of treatment resistance. Measuring carbonic anhydrase 9 levels may be helpful in determining which patients benefit from therapy.

Sunitinib treatment exacerbates intratumoral heterogeneity in metastatic renal cancer

Purpose: The aim of this study was to investigate the effect of VEGF-targeted therapy (sunitinib) on molecular intratumoral heterogeneity (ITH) in metastatic clear cell renal cancer (mccRCC). Experimental Design: Multiple tumor samples (n = 187 samples) were taken from the primary renal tumors of patients with mccRCC who were sunitinib treated (n = 23, SuMR clinical trial) or untreated (n = 23, SCOTRRCC study). ITH of pathologic grade, DNA (aCGH), mRNA (Illumina Beadarray) and candidate proteins (reverse phase protein array) were evaluated using unsupervised and supervised analyses (driver mutations, hypoxia, and stromal-related genes). ITH was analyzed using intratumoral protein variance distributions and distribution of individual patient aCGH and gene-expression clustering. Results: Tumor grade heterogeneity was greater in treated compared with untreated tumors (P = 0.002). In unsupervised analysis, sunitinib therapy was not associated with increased ITH in DNA or mRNA. However, there was an increase in ITH for the driver mutation gene signature (DNA and mRNA) as well as increasing variability of protein expression with treatment (P < 0.05). Despite this variability, significant chromosomal and transcript changes to key targets of sunitinib, such as VHL, PBRM1, and CAIX, occurred in the treated samples. Conclusions: These findings suggest that sunitinib treatment has significant effects on the expression and ITH of key tumor and treatment specific genes/proteins in mccRCC. The results, based on primary tumor analysis, do not support the hypothesis that resistant clones are selected and predominate following targeted therapy. Clin Cancer Res; 21(18); 4212–23. ©2015 AACR.

The Use of Automated Quantitative Analysis to Evaluate Epithelial-to-Mesenchymal Transition Associated Proteins in Clear Cell Renal Cell Carcinoma

Background Epithelial-to-mesenchymal transition (EMT) has recently been implicated in the initiation and progression of renal cell carcinoma (RCC). Some mRNA gene expression studies have suggested a link between the EMT phenotype and poorer clinical outcome from RCC. This study evaluated expression of EMT-associated proteins in RCC using in situ automated quantitative analysis immunofluorescence (AQUA) and compared expression levels with clinical outcome. Methods/Principal Findings Unsupervised hierarchical cluster analysis of pre-existing RCC gene expression array data (GSE16449) from 36 patients revealed the presence of an EMT transcriptional signature in RCC [E-cadherin high/SLUG low/SNAIL low]. As automated immunofluorescence technology is dependent on accurate definition of the tumour cells in which measurements take place is critical, extensive optimisation was carried out resulting in a novel pan-cadherin based tumour mask that distinguishes renal cancer cells from stromal components. 61 patients with ccRCC and clinical follow-up were subsequently assessed for expression of EMT-associated proteins (WT1, SNAIL, SLUG, E-cadherin and phospho-β-catenin) on tissue microarrays. Using Kaplan-Meier analysis both SLUG (p = 0.029) and SNAIL (p = 0.024) (log rank Mantel-Cox) were significantly associated with prolonged progression free survival (PFS). Using Cox regression univariate and multivariate analysis none of the biomarkers were significantly correlated with outcome. 14 of the 61 patients expressed the gene expression analysis predicted EMT-protein signature [E-cadherin high/SLUG low/SNAIL low], which was not found to be associated to PFS when measured at the protein level. A combination of high expression of SNAIL and low stage was able to stratify patients with greater significance (p = 0.001) then either variable alone (high SNAIL p = 0.024, low stage p = 0.029). Conclusions AQUA has been shown to have the potential to identify EMT related protein targets in RCC allowing for stratification of patients into high and low risk groups, as well the ability to assess the association of reputed EMT signatures to progression of the disease.

The use of reverse phase protein arrays (RPPA) to explore protein expression variation within individual renal cell cancers.

Currently there is no curative treatment for metastatic clear cell renal cell cancer, the commonest variant of the disease. A key factor in this treatment resistance is thought to be the molecular complexity of the disease. Targeted therapy such as the tyrosine kinase inhibitor (TKI)-sunitinib have been utilized, but only 40% of patients will respond, with the overwhelming majority of these patients relapsing within 1 year. As such the question of intrinsic and acquired resistance in renal cell cancer patients is highly relevant. In order to study resistance to TKIs, with the ultimate goal of developing effective, personalized treatments, sequential tissue after a specific period of targeted therapy is required, an approach which had proved successful in chronic myeloid leukaemia. However the application of such a strategy in renal cell carcinoma is complicated by the high level of both inter- and intratumoral heterogeneity, which is a feature of renal cell carcinoma as well as other solid tumors. Intertumoral heterogeneity due to transcriptomic and genetic differences is well established even in patients with similar presentation, stage and grade of tumor. In addition it is clear that there is great morphological (intratumoral) heterogeneity in RCC, which is likely to represent even greater molecular heterogeneity. Detailed mapping and categorization of RCC tumors by combined morphological analysis and Fuhrman grading allows the selection of representative areas for proteomic analysis. Protein based analysis of RCC is attractive due to its widespread availability in pathology laboratories; however, its application can be problematic due to the limited availability of specific antibodies. Due to the dot blot nature of the Reverse Phase Protein Arrays (RPPA), antibody specificity must be pre-validated; as such strict quality control of antibodies used is of paramount importance. Despite this limitation the dot blot format does allow assay miniaturization, allowing for the printing of hundreds of samples onto a single nitrocellulose slide. Printed slides can then be analyzed in a similar fashion to Western analysis with the use of target specific primary antibodies and fluorescently labelled secondary antibodies, allowing for multiplexing. Differential protein expression across all the samples on a slide can then be analyzed simultaneously by comparing the relative level of fluorescence in a more cost-effective and high-throughput manner.

Proteomic analysis of pre- and post-sunitinib treated renal cancer tissue to assess tumor heterogeneity and differential protein expression.

388 Background: To investigate acquired resistance of clear cell renal cell cancer (ccRCC) patients to sunitinib and develop personalised treatment strategies, sequential tissue after a specific period of targeted therapy is required. This approach has proven successful with targeted therapy in chronic myeloid leukaemia; however, we are concerned that extensive tumour heterogeneity occurs in ccRCC. In this study we evaluated heterogeneity and differential protein expression in sunitinib treated and untreated ccRCC samples using high-throughput proteomics. METHODS Fresh frozen tissue was obtained from 27 sunitinib naïve ccRCC specimens and 27 nephrectomy samples from patients treated with neoadjuvant sunitinib (18 weeks) as part of the SuMR trial. From each tumour frozen sections were performed and up to 5 protein lysates obtained from each morphologically differing region of each tumour as well as matched normal kidney. Reverse phase protein arrays (RPPA) were performed to assess the levels of multiple proteins relevant to ccRCC pathogenesis and sunitinib activity. Appropriate statistical tests were used to examine protein heterogeneity and differential expression, including false discovery rate (FDR) correction. Kaplan-Meier method was used to correlate changes in protein expression with outcome. RESULTS Expression of 20 proteins has been examined to date. The range of expression in tumours normalised by matched normal renal tissue had >2-fold differences in untreated (n=8 proteins) and treated samples (n=4 proteins). Four markers displayed significantly increased inter-tumoural variance in sunitinib treated tumours compared with untreated tissue (e.g. VEGFR1, FDR P<0.05). Despite this heterogeneity, sunitinib was associated with significant expression changes for several key proteins (e.g. VEGFR2, CyclinD2; FDR P<0.05). CONCLUSIONS Protein expression in ccRCC is heterogenous and key proteins showed significantly increased variance of expression with sunitinib therapy. Despite heterogeneity, significant changes in protein expression can be identified with sunitinib treatment and have been correlated with outcome.

Utilizing mRNA extracted from small, archival formalin-fixed paraffin-embedded prostate samples for translational research: assessment of the effect of increasing sample age and storage temperature.

IntroductionTranslational prostate cancer research is hampered by long intervals from diagnosis to patient progression and difficulty in obtaining cancer tissue for investigation. As such, it is imperative to utilise aging formalin-fixed paraffin-embedded (FFPE) tissue samples from the pathology archive with linked patient outcome data to allow current day research. This study aimed to assess the adequacy and quantity of mRNA extracted from formalin fixed paraffin embedded (FFPE) prostate tissue, including prostate biopsies, up to 15 years old. The decay of mRNA over time and under differing storage conditions was also assessed.Materials and methodsArchived FFPE benign prostatic tissue up to 15 years old from transurethral resection of the prostate (TURP) and transrectal ultrasound guided (TRUS) biopsies as well as fresh tissue obtained from patients undergoing TURP for benign bladder outlet obstruction were used. Following mRNA extraction beta-actin real-time PCR was carried out using a set of 4 different primer/probes to assess mRNA quality and quantity.ResultsThere was no difference in mRNA quantity/quality extracted from “fresh” FFPE tissue from the same patient over a 4-month period following surgery. The temperature of block storage did not alter quality/quantity of the mRNA (P > 0.05, unpaired t test). Fresh tissue had a higher quality/quantity, indicated by a lower CT value, than FFPE samples from the same patient (P ≤ 0.03, one-way ANOVA). Despite being up to 15 years old, all archived FFPE TURP and TRUS biopsy samples had “high” or “very high” levels of expression making them suitable for further analysis. However, the quality of the mRNA in archived FFPE samples did significantly decline with increasing sample age.ConclusionsIt is possible to extract mRNA of sufficient standard for further transcriptomic analysis from minute FFPE samples up to 15 years old. This work adds to the literature suggesting that exploitation of retrospective prostate tissue collections with robust associated clinical data is possible.