Targeting DNA topoisomerase IIα (TOP2A) in the hypoxic tumour microenvironment using unidirectional hypoxia-activated prodrugs (uHAPs).

The hypoxic tumour microenvironment (hTME), arising from inadequate and chaotic vascularity, can present a major obstacle for the treatment of solid tumours. Hypoxic tumour cells compromise responses to treatment since they can generate resistance to radiotherapy, chemotherapy and immunotherapy. The hTME impairs the delivery of a range of anti-cancer drugs, creates routes for metastasis and exerts selection pressures for aggressive phenotypes; these changes potentially occur within an immunosuppressed environment. Therapeutic strategies aimed at the hTME include targeting the molecular changes associated with hypoxia. An alternative approach is to exploit the prevailing lack of oxygen as a principle for the selective activation of prodrugs to target cellular components within the hTME. This review focuses on the design concepts and rationale for the use of unidirectional Hypoxia-Activated Prodrugs (uHAPs) to target the hTME as exemplified by the uHAPs AQ4N and OCT1002. These agents undergo irreversible reduction in a hypoxic environment to active forms that target DNA topoisomerase IIα (TOP2A). This nuclear enzyme is essential for cell division and is a recognised chemotherapeutic target. An activated uHAP interacts with the enzyme-DNA complex to induce DNA damage, cell cycle arrest and tumour cell death. uHAPs are designed to overcome the shortcomings of conventional HAPs and offer unique pharmacodynamic properties for effective targeting of TOP2A in the hTME. uHAP therapy in combination with standard of care treatments has the potential to enhance outcomes by co-addressing the therapeutic challenge presented by the hTME.

The unidirectional hypoxia-activated prodrug OCT1002 inhibits growth and vascular development in castrate-resistant prostate tumors.

BACKGROUND: OCT1002 is a unidirectional hypoxia-activated prodrug (uHAP) OCT1002 that can target hypoxic tumor cells. Hypoxia is a common feature in prostate tumors and is known to drive disease progression and metastasis. It is, therefore, a rational therapeutic strategy to directly target hypoxic tumor cells in an attempt to improve treatment for this disease. Here we tested OCT1002 alone and in combination with standard-of-care agents in hypoxic models of castrate-resistant prostate cancer (CRPC). METHODS: The effect of OCT1002 on tumor growth and vasculature was measured using murine PC3 xenograft and dorsal skin fold (DSF) window chamber models. The effects of abiraterone, docetaxel, and cabazitaxel, both singly and in combination with OCT1002, were also compared. RESULTS: The hypoxia-targeting ability of OCT1002 effectively controls PC3 tumor growth. The effect was evident for at least 42 days after exposure to a single dose (30 mg/kg) and was comparable to, or better than, drugs currently used in the clinic. In DSF experiments OCT1002 caused vascular collapse in the PC3 tumors and inhibited the revascularization seen in controls. In this model OCT1002 also enhanced the anti-tumor effects of abiraterone, cabazitaxel, and docetaxel; an effect which was accompanied by a more prolonged reduction in tumor vasculature density. CONCLUSIONS: These studies provide the first evidence that OCT1002 can be an effective agent in treating hypoxic, castrate-resistant prostate tumors, either singly or in combination with established chemotherapeutics for prostate cancer.

Nitric Oxide Up-Regulates RUNX2 in LNCaP Prostate Tumours: Implications for Tumour Growth In Vitro and In Vivo.

Aberrant expression of the transcription factor RUNX2 in prostate cancer has a number of important consequences including increased resistance to apoptosis, invasion and metastasis to bone. We previously demonstrated that hypoxia up-regulated RUNX2 in tumour cells, which in turn up-regulated the anti-apoptotic factor Bcl-2. Here, we investigate the impact of nitric oxide (NO) on RUNX2 and Bcl-2 expression in prostate cancer and further, how RUNX2 over-expression can impact tumour growth, angiogenesis and oxygenation in vivo. The effect of NO levels on RUNX2 and thus Bcl-2 expression was examined in prostate cancer cells in vitro using methods including gene and protein expression analyses, nitrite quantitation, protein-DNA interaction assays (ChIP) and viability assays (XTT). The effect of RUNX2 over-expression on tumour physiology (growth, oxygenation and angiogenesis) was also assessed in vivo using LNCaP xenografts. A low (but not high) concentration of NO (10 µM) induced expression of RUNX2 and Bcl-2, conferring resistance to docetaxel. These effects were induced via the ERK and PI3K pathways and were dependent on intact AP-1 binding sites in the RUNX2 promoter. RUNX2 over-expression in LNCaP tumours in vivo decreased the time to tumour presentation and increased tumour growth. Moreover, these tumours exhibited improved tumour angiogenesis and oxygenation. Low levels of NO increase expression of RUNX2 and Bcl-2 in LNCaP prostate tumour cells, and in vivo up-regulation of RUNX2 created tumours with a more malignant phenotype. Collectively, our data reveals the importance of NO-regulation of key factors in prostate cancer disease progression.

Comet assay measures of DNA damage are predictive of bladder cancer cell treatment sensitivity in vitro and outcome in vivo.

Bladder cancer patients suffer significant treatment failure, including high rates of recurrence and poor outcomes for advanced disease. If mechanisms to improve tumour cell treatment sensitivity could be identified and/or if tumour response could be predicted, it should be possible to improve local-control and survival. Previously, we have shown that radiation-induced DNA damage, measured by alkaline Comet assay (ACA), correlates bladder cancer cell radiosensitivity in vitro. In this study we first show that modified-ACA measures of cisplatin and mitomycin-C-induced damage also correlate bladder cancer cell chemosensitivity in vitro, with essentially the same rank order for chemosensitivity as for radiosensitivity. Furthermore, ACA studies of radiation-induced damage in different cell-DNA substrates (nuclei, nucleoids and intact parent cells) suggest that it is a feature retained in the prepared nucleoids that is responsible for the relative damage sensitivity of bladder cancer cells, suggestive of differences in the organisation of DNA within resistant vs. sensitive cells. Second, we show that ACA analysis of biopsies from bladder tumours reveal that reduced DNA damage sensitivity associates with poorer treatment outcomes, notably that tumours with a reduced damage response show a significant association with local recurrence of non-invasive disease and that reduced damage response was a better predictor of recurrence than the presence of high-risk histology in this cohort. In conclusion, this study demonstrates that mechanisms governing treatment-induced DNA damage are both central to and predictive of bladder cancer cell treatment sensitivity and exemplifies a link between DNA damage resistance and both treatment response and tumour aggression.

Androgen deprivation results in time-dependent hypoxia in LNCaP prostate tumours: informed scheduling of the bioreductive drug AQ4N improves treatment response.

Androgen withdrawal induces hypoxia in androgen-sensitive tissue; this is important as in the tumour microenvironment, hypoxia is known to drive malignant progression. Our study examined the time-dependent effect of androgen deprivation therapy (ADT) on tumour oxygenation and investigated the role of ADT-induced hypoxia on malignant progression in prostate tumours. LNCaP xenografted tumours were treated with anti-androgens and tumour oxygenation measured. Dorsal skin fold (DSF) chambers were used to image tumour vasculature in vivo. Quantitative PCR (QPCR) identified differential gene expression following treatment with bicalutamide. Bicalutamide-treated and vehicle-only-treated tumours were re-established in vitro, and invasion and sensitivity to docetaxel were measured. Tumour growth delay was calculated following treatment with bicalutamide combined with the bioreductive drug AQ4N. Tumour oxygenation measurements showed a precipitate decrease following initiation of ADT. A clinically relevant dose of bicalutamide (2 mg/kg/day) decreased tumour oxygenation by 45% within 24 hr, reaching a nadir of 0.09% oxygen (0.67 ± 0.06 mmHg) by Day 7; this persisted until Day 14 when it increased up to Day 28. Using DSF chambers, LNCaP tumours treated with bicalutamide showed loss of small vessels at Days 7 and 14 with revascularisation occurring by Day 21. QPCR showed changes in gene expression consistent with the vascular changes and malignant progression. Cells from bicalutamide-treated tumours were more malignant than vehicle-treated controls. Combining bicalutamide with AQ4N (50 mg/kg, single dose) caused greater tumour growth delay than bicalutamide alone. Our study shows that bicalutamide-induced hypoxia selects for cells that show malignant progression; targeting hypoxic cells may provide greater clinical benefit.

Ultrasound targeted microbubble destruction using docetaxel and Rose Bengal loaded Microbubbles for targeted Chemo-Sonodynamic therapy treatment of prostate cancer.

Docetaxel (DTX) chemotherapy is commonly used in the treatment of patients with advanced prostate cancer demonstrating modest improvements in survival. As these patients are often elderly and the chemotherapy treatment is not targeted, it is often poorly tolerated. More targeted approaches that increase therapeutic efficacy yet reduce the amount of toxic chemotherapy administered are needed. In this manuscript, we investigate the potential of ultrasound targeted microbubble destruction (UTMD) to deliver a combination of docetaxel chemotherapy and Rose Bengal mediated sonodynamic therapy (SDT) in pre-clinical prostate cancer models. A Rose Bengal modified phospholipid was synthesized and used as a component lipid to prepare a microbubble (MB) formulation that was also loaded with DTX. The DTX-MB-RB formulation was used in the UTMD mediated treatment of androgen sensitive and androgen resistant 3D spheroid and murine models of prostate cancer. Results from the 3D spheroid experiments showed UTMD mediated DTX-MB-RB chemo-sonodynamic therapy to be significantly more effective at reducing cell viability than UTMD mediated DTX or SDT treatment alone. In an androgen sensitive murine model of prostate cancer, UTMD mediated DTX-MB-RB chemo-sonodynamic therapy was as effective as androgen deprivation therapy (ADT) at controlling tumour growth. However, when both treatments were combined, a significant improvement in tumour growth delay was observed. In an androgen resistant murine model, UTMD mediated DTX-MB-RB chemo-sonodynamic therapy was significantly more effective than standard DTX monotherapy. Indeed, the DTX dose administered using the DTX-MB-RB formulation was 91% less than standard DTX monotherapy. As a result, UTMD mediated DTX-MB-RB treatment was well tolerated while animals treated with DTX monotherapy displayed significant weight loss which was attributed to acute toxic effects. These results highlight the potential of UTMD mediated DTX-MB-RB chemo-sonodynamic therapy as a targeted, well tolerated alternative treatment for advanced prostate cancer.

Cytochrome P450 1B1 mRNA untranslated regions interact to inhibit protein translation.

CYP1B1 mRNA is expressed constitutively in all normal extrahepatic human tissues, though the protein is usually undetectable. In contrast, CYP1B1 protein is expressed at high levels in tumors. In this study CYP1B1 mRNA and protein expression was measured in a panel of cell lines indicating that CYP1B1 regulation is altered in tumor cell lines in vitro. Interrogation of ONCOMINE revealed that CYP1B1 mRNA is not significantly overexpressed in tumors compared to normal tissues, suggesting CYP1B1 is subject to posttranscriptional control. Analysis of the CYP1B1 mRNA revealed a complex 5' untranslated region (UTR) containing a small upstream open-reading frame (uORF). These features are present in mRNAs subject to translational control so the effect of the 5'UTR was tested using in vitro translation in CHO-K1 cells. The 5'UTR significantly inhibited luciferase reporter gene translation, and mutation of the uORF start codon abolished the inhibitory effect. The 5'UTR also interacted with the microRNA-27b recognition element in the CYP1B1 mRNA 3'UTR to almost completely inhibit translation. CYP1B1 is subject to a high degree of translational control, which may explain the absence of protein expression in normal cells. Alterations in translational control during malignant transformation may help to explain the tumor-specific expression of CYP1B1 protein.

Young women's responses to smoking and breast cancer risk information.

Current evidence confirms that young women who smoke or who have regular long-term exposure to secondhand smoke (SHS) have an increased risk of developing premenopausal breast cancer. The aim of this research was to examine the responses of young women to health information about the links between active smoking and SHS exposure and breast cancer and obtain their advice about messaging approaches. Data were collected in focus groups with 46 women, divided in three age cohorts: 15-17, 18-19 and 20-24 and organized according to smoking status (smoking, non-smoking and mixed smoking status groups). The discussion questions were preceded by information about passive and active smoking and its associated breast cancer risk. The study findings show young women's interest in this risk factor for breast cancer. Three themes were drawn from the analysis: making sense of the information on smoking and breast cancer, personal susceptibility and tobacco exposure and suggestions for increasing awareness about tobacco exposure and breast cancer. There was general consensus on framing public awareness messages about this risk factor on 'protecting others' from breast cancer to catch smokers' attention, providing young women with the facts and personal stories of breast cancer to help establish a personal connection with this information and overcome desensitization related to tobacco messages, and targeting all smokers who may place young women at risk. Cautions were also raised about the potential for stigmatization. Implications for raising awareness about this modifiable risk factor for breast cancer are discussed.

Breast cancer messaging for younger women: gender, femininity, and risk.

Evidence linking both active smoking and secondhand smoke exposure to premenopausal breast cancer makes the development of health messages specific to younger women a pressing priority. To determine how to communicate information about this modifiable breast cancer risk to young women, we analyzed a selection of 32 recent English-language breast cancer messages and campaigns that targeted young women. In addition, we obtained young women's responses to three breast cancer campaign images during focus group discussions. A visual analysis of messages points to an explicitly gendered discourse within contemporary campaigns, one that entails conflicting messages regarding breast cancer, health, feminine beauty, and risk. Although the intent might be to educate and empower young women to "fight" against breast cancer, paradoxically, the messages employ imagery that sexually objectifies young women's breasts and bodies. Recommendations are made for messaging about tobacco and breast cancer risk to avoid reproducing one-dimensional or stereotypical presentations of gender and femininity.

Cytochrome P450 1B1 expression in rat esophageal tumorigenesis promoted by gastric and duodenal reflux.

Cytochrome P450 1B1 (CYP1B1) mRNA is constitutively expressed in most normal extra-hepatic tissues; however the protein is not detectable in these tissues but is expressed in a wide variety of tumors. CYP1B1 is responsible for the activation of a number of carcinogens present in tobacco smoke and food. A surgical model of rat esophageal tumorigenesis, promoted by gastric or duodenal reflux was used to determine CYP1B1 expression in premalignant esophageal tissue. Immunohistochemistry was performed using a modified amplified fluorescein tyramide protocol. CYP1B1 was not observed in normal esophageal mucosa, submucosa, or muscularis mucosa. Animals exposed to gastric reflux developed mild hyperplasia. Varying degrees of hyperplasia were observed in the duodenal reflux group. All regions of hyperplasia showed moderate or strong CYP1B1 immunoreactivity. Duodenal reflux induced a small number of premalignant changes: immunoreactivity was absent from the epithelium of squamous dysplasia (0/10), Barrett's esophagus (0/7), and majority of dysplastic Barrett's esophagus (1/4). Moderate or strong immunoreactivity was observed in the majority (7/8) of squamous cell carcinomas (SCCs) in situ. Immunoreactivity was also observed in the lamina propria and submucosa in association with inflammation, regardless of the severity of inflammation. The expression of CYP1B1 in hyperplasia, SCCs in situ, or in association with inflammation may increase the production of carcinogenic metabolites, which may promote esophageal tumorigenesis.

Evaluation of the antiangiogenic potential of AQ4N.

PURPOSE: A number of cytotoxic chemotherapy agents tested at low concentrations show antiangiogenic properties with limited cytotoxicity, e.g., cyclophosphamide, tirapazamine, and mitoxantrone. AQ4N is a bioreductive alkylaminoanthraquinone that is cytotoxic when reduced to AQ4; hence, it can be used to target hypoxic tumor cells. AQ4N is structurally similar to mitoxantrone and was evaluated for antiangiogenic properties without the need for bioreduction. EXPERIMENTAL DESIGN: The effect of AQ4N and fumagillin on human microvascular endothelial cells (HMEC-1) was measured using a variety of in vitro assays, i.e., 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound scrape, tubule formation, rat aortic ring, and invasion assays. Low-dose AQ4N (20 mg/kg) was also given in vivo to mice bearing a tumor in a dorsal skin flap. RESULTS: AQ4N (10(-11) to 10(-5) mol/L) had no effect on HMEC-1 viability. AQ4N (10(-9) to 10(-5)mol/L) caused a sigmoidal dose-dependent inhibition of endothelial cell migration in the wound scrape model. Fumagillin showed a similar response over a lower dose range (10(-13) to 10(-9) mol/L); however, the maximal inhibition was less (25% versus 43% for AQ4N). AQ4N inhibited HMEC-1 cell contacts on Matrigel (10(-8) to 10(-5) mol/L), HMEC-1 cell invasion, and sprouting in rat aorta explants. Immunofluorescence staining with tubulin, vimentim, dynein, and phalloidin revealed that AQ4N caused disruption to the cell cytoskeleton. When AQ4N (20 mg/kg) was given in vivo for 5 days, microvessels disappeared in LNCaP tumors grown in a dorsal skin flap. CONCLUSIONS: This combination of assays has shown that AQ4N possesses antiangiogenic effects in normoxic conditions, which could potentially contribute to antitumor activity.

Nurses' use of qualitative research approaches to investigate tobacco use and control.

Qualitative research methods are increasingly used by nurse scientists to explore a wide variety of topics relevant to practice and/or health policy issues. The purpose of this chapter is to review the contributions of nurse scientists to the field of tobacco control through the use of qualitative research methods. A systematic literature search strategy was used to identify 51 articles published between 1980 and 2008. The majority (84%) of reviewed articles were authored by North American nurse scientists. Cessation was the most commonly (85%) studied aspect of tobacco control. Six qualitative research approaches were used: qualitative descriptive (55%), narrative analysis (8%), phenomenology (6%), grounded theory (14%), ethnography (12%), and case study (6%). Qualitative descriptive methods were primarily one-off studies to address practical problems or issues encountered in practice, and often validated current understandings related to tobacco. Researchers who used other types of qualitative methods and who conducted qualitative studies as part of programs of research were more likely to make more substantive contributions to the evolving field of tobacco control. These contributions related to how smoking intertwines with personal and social identities, the influence of social context on tobacco use, and nurses' involvement in tobacco control (both of their own tobacco use and in assisting others). Nurse scientists interested in exploring tobacco-related issues are encouraged to consider the full range of qualitative research approaches. Qualitative research methods contribute to our understanding of tobacco use arising from nursing practice, health care and policy, along with the field of tobacco control in general.

Hypoxia selects for androgen independent LNCaP cells with a more malignant geno- and phenotype.

Hypoxia confers resistance to common cancer therapies, however, it has also has been shown to result in genetic alterations which may allow a survival advantage and increase the tumorigenic properties of cancer cells. Additionally, it may exert a selection pressure, allowing expansion of tumor cells with a more aggressive phenotype. To further assess the role of hypoxia in malignant progression in prostate cancer we exposed human androgen dependent prostate cancer cells (LNCaP) to cycles of chronic hypoxia and isolated a subline, LNCaP-H1. This article describes the partial characterization of this cell line. The LNCaP-H1 subline showed altered growth characteristics and exhibited androgen independent growth both in vitro and in vivo. Furthermore, these cells were resistant to mitochondrial-mediated apoptosis, probably since the endogenous levels of Bax was lower and Bcl-2 higher than in the parental LNCaP cells. Microarray analysis revealed that a complex array of pathways had differential gene expression between the 2 cell lines, with LNCaP-H1 cells exhibiting a genetic profile which suggests that they may be more likely metastasize to distant organs, especially bone. This was supported by an in vitro invasion assay, and an in vivo metastasis study. This study shows that hypoxia can select for androgen independent prostate cancer cells which have a survival advantage and are more likely to invade and metastasize.

Potential use of the comet assay in the clinical management of cancer.

The comet assay has been widely used to measure a range of cellular responses to DNA damage and has found applications in genotoxicity studies, bio-monitoring, ecological testing and in the study of human disease. This review discusses how the comet assay has been applied to the study of DNA damage and repair associated with cancer. The potential of the assay as a tool for predicting an individual's tumour sensitivity to radiation and to various chemotherapeutic drugs is examined, as well as outlining the usefulness of the assay in assessing oxidative stress within tumours. In addition, we review the use of the comet assay in investigations of the DNA-damaging effect of anti-neoplastic drugs and radiation used during cancer therapy. The advantages and limitations of the comet assay in carrying out all these studies are outlined, and the suitability of the comet assay for use in the clinical management of cancer is discussed.

Investigation of pericytes, hypoxia, and vascularity in bladder tumors: association with clinical outcomes.

The contribution of endothelial cell growth to angiogenesis has been widely studied; however, the involvement of pericytes is less well documented, especially in human tumors. In this study we aimed to quantify and assess the prognostic significance of pericyte coverage, the extent of hypoxia, and microvessel density (MVD) in normal bladder mucosa and urothelial carcinoma. Antibody to alpha-smooth muscle actin was used to assess the distribution of pericytes (mural/smooth muscle cells) in the microvessels of normal human bladder (n = 4) mucosa and in urothelial carcinoma (n = 47) samples; this was quantitated using microvessel pericyte index (MPI). The MVD was measured using two different methods (n = 47) and hypoxia was assessed using glucose transporter-1 (Glut-1) staining (n = 30). There was a 70% reduction in MPI in urothelial carcinomas compared to normal bladder mucosa (p < 0.0012); MPI did not correlate with tumor stage or grade. Ta and T1 superficial tumors were divided into two groups with a MPI of <15% or >15%. Progression-free survival was significantly shorter for tumors with MPI >15% (p = 0.0036). MVD had no prognostic value using either evaluation method. Glut-1 immunoreactivity was not prognostic in superficial urothelial carcinoma samples. Tumors with a higher MPI showed a greater Glut-1 immunoreactivity (p = 0.0051). Microvessels in urothelial carcinoma have a considerable loss of pericyte coverage compared to normal bladder mucosa. The data from this preliminary study indicate that progression-free survival was shorter in patients whose superficial tumors had higher pericyte coverage of the microvessels. This may be due to increased levels of hypoxia, as demonstrated by a significant increase in Glut-1 staining.

Pericytes influence endothelial cell growth characteristics: role of plasminogen activator inhibitor type 1 (PAI-1).

OBJECTIVE: Pericytes, located in close proximity to the underlying endothelium, form an integral component of the microvasculature. These cells are intimately involved in angiogenesis, which is of fundamental importance in many physiological and pathological processes. We evaluated the influence of pericyte-conditioned medium (PCM) on endothelial cell growth characteristics and modulation of endothelial gene expression. METHODS: Migration and tubule formation assays were performed in vitro to determine the effect of PCM on endothelial growth characteristics. cDNA microarray analysis was used to identify alterations in gene expression following exposure of human microvascular endothelial cells (HMEC-1) to PCM. Overexpression of PAI-1 using recombinant protein or transient transfection, and inhibition using an inhibitory antibody against PAI-1, were used to determine whether up- or down-regulation of this gene was responsible for the changes in endothelial cell characteristics observed in response to PCM exposure. RESULTS: We have shown that PCM exerts a dramatic inhibitory influence on endothelial cell migration in vitro. In addition, endothelial cells cultured on Matrigel and exposed to PCM were found to generate significantly fewer angiogenic branches. Microarray analysis of endothelial cells exposed to PCM identified PAI-1 as the gene showing the greatest level of differential expression (3.4-fold induction). Studies using an inhibitory antibody to PAI-1 suggest that induction of this protein by PCM is pivotal to the observed inhibitory influence on the migratory and angiogenic potential of HMEC-1. We further investigated this by overexpressing PAI-1, which was shown to have a potent inhibitory influence on EC migration and angiogenic branching, although the concentration of PAI-1 was clearly important. CONCLUSION: Collectively, these findings suggest that PCM contains a bioactive element(s) that controls both endothelial cell migration and tubule formation in vitro and that these responses may be partially controlled by increased endothelial cell expression of PAI-1.

Targeting Hypoxic Prostate Tumors Using the Novel Hypoxia-Activated Prodrug OCT1002 Inhibits Expression of Genes Associated with Malignant Progression.

Purpose: To understand the role of hypoxia in prostate tumor progression and to evaluate the ability of the novel unidirectional hypoxia-activated prodrug OCT1002 to enhance the antitumor effect of bicalutamide.Experimental Design: The effect of OCT1002 on prostate cancer cells (LNCaP, 22Rv1, and PC3) was measured in normoxia and hypoxia in vitroIn vivo, tumor growth and lung metastases were measured in mice treated with bicalutamide, OCT1002, or a combination. Dorsal skin fold chambers were used to image tumor vasculature in vivo Longitudinal gene expression changes in tumors were analyzed using PCR.Results: Reduction of OCT1002 to its active form (OCT1001) decreased prostate cancer cell viability. In LNCaP-luc spheroids, OCT1002 caused increased apoptosis and decreased clonogenicity. In vivo, treatment with OCT1002 alone, or with bicalutamide, showed significantly greater tumor growth control and reduced lung metastases compared with controls. Reestablishment of the tumor microvasculature following bicalutamide-induced vascular collapse is inhibited by OCT1002. Significantly, the upregulation of RUNX2 and its targets caused by bicalutamide alone was blocked by OCT1002.Conclusions: OCT1002 selectively targets hypoxic tumor cells and enhances the antitumor efficacy of bicalutamide. Furthermore, bicalutamide caused changes in gene expression, which indicated progression to a more malignant genotype; OCT1002 blocked these effects, emphasizing that more attention should be attached to understanding genetic changes that may occur during treatment. Early targeting of hypoxic cells with OCT1002 can provide a means of inhibiting prostate tumor growth and malignant progression. This is of importance for the design and refinement of existing androgen-deprivation regimens in the clinic. Clin Cancer Res; 23(7); 1797-808. ©2016 AACR.

Mutant SOD1 mediated pathogenesis of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neural disorder that causes death of the motor neurons in the brain and spinal cord; this affects the voluntary muscles and gradually leads to paralysis of the whole body. Most ALS cases are sporadic, though about 5-10% are familial. ALS is caused by multiple factors including mutation in any one of a number of specific genes, one of the most frequently affected is superoxide dismutase (SOD) 1. Alterations in SOD 1 have been linked with several variants of familial ALS. SOD 1 is a powerful antioxidant enzyme that protects cells from the damaging effects of superoxide radicals. The enzyme binds both copper and zinc ions that are directly involved in the deactivation of toxic superoxide radicals. Mutated SOD1 gene can acquire both gain and loss of function mutations. The most commonly identified mutations in SOD1 that affect protein activity are D90A, A4V and G93A. Deleterious mutations have been shown to modify SOD1 activity, which leads to the accumulation of highly toxic hydroxyl radicals. Accumulation of these free radicals causes degradation of both nuclear and mitochondrial DNA and protein misfolding, features which can be used as pathological indicators associated with ALS. Numerous clinical trials have been carried out over last few years with limited success. In some patients advanced techniques like gene and stem cell therapy have been trialed. However no definitive treatment option can provide a cure and currently ALS is managed by drugs and other supportive therapies. Consequently there is a need to identify new approaches for treatment of this ultimately fatal disease.

Modification of the alkaline Comet assay to allow simultaneous evaluation of mitomycin C-induced DNA cross-link damage and repair of specific DNA sequences in RT4 cells.

The alkaline Comet assay is a simple, sensitive method for measuring the extent of DNA strand breaks in individual cells. Several modifications to the original assay have been developed to increase its applications. One such modification allows the measurement of DNA cross-links by assessing the relative reduction in DNA migration induced by a strand-breaking agent. Another modification includes the application of fluorescent in situ hybridisation (FISH) to investigate the localisation of specific gene domains within a cell. Although several studies have used these approaches separately, no report to date has combined these two versions of the Comet assay. The current study describes the modification of the Comet assay, to allow both measurement of mitomycin C (MMC)-induced cross-links and the subsequent application of FISH to study repair in the TP53 gene region. RT4 human bladder cancer cells were treated with 0, 5, 50 and 200 microg/ml MMC to study dose response, whilst for cross-link repair studies, they were treated with 50 microg/ml MMC and allowed to repair for up to 24 h. A clear dose response to MMC was displayed, demonstrable by a marked reduction in DNA migration, whilst repair studies showed that MMC-induced cross-links take at least 24 h to repair fully in RT4 cells. For Comet-FISH experiments, the number and location of TP53 hybridisation spots was also recorded for each cell. In dose response experiments, the number of spots per cell, and per Comet tail, decreased as MMC dose increased. In repair experiments, the number of spots, particularly in the Comet tail, increased as repair time increased. Furthermore, our results suggest that repair of the TP53 gene region is most rapid within the first 4 h following MMC treatment. We conclude that the novel experimental protocol presented here has considerable potential in evaluating DNA damage and sequence-related repair responses to cross-linking agents.

Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation.

Most radiotherapy (RT) involves the use of high doses (>50 Gy) to treat malignant disease. However, low to intermediate doses (approximately 3-50 Gy) can provide effective control of a number of benign conditions, ranging from inflammatory/proliferative disorders (e.g. Dupuytren's disease, heterotopic ossification, keloid scarring, pigmented villonodular synovitis) to benign tumours (e.g. glomus tumours or juvenile nasopharyngeal angiofibromas). Current use in UK RT departments is very variable. This review identifies those benign diseases for which RT provides good control of symptoms with, for the most part, minimal side effects. However, exposure to radiation has the potential to cause a radiation-induced cancer (RIC) many years after treatment. The evidence for the magnitude of this risk comes from many disparate sources and is constrained by the small number of long-term studies in relevant clinical cohorts. This review considers the types of evidence available, i.e. theoretical models, phantom studies, epidemiological studies, long-term follow-up of cancer patients and those treated for benign disease, although many of the latter data pertain to treatments that are no longer used. Informative studies are summarized and considered in relation to the potential for development of a RIC in a range of key tissues (skin, brain etc.). Overall, the evidence suggests that the risks of cancer following RT for benign disease for currently advised protocols are small, especially in older patients. However, the balance of risk vs benefit needs to be considered in younger adults and especially if RT is being considered in adolescents or children.