Hypoxia-inducible factor 1 alpha is required for the tumourigenic and aggressive phenotype associated with Rab25 expression in ovarian cancer

The small GTPase Rab25 has been functionally linked to tumour progression and aggressiveness in ovarian cancer and promotes invasion in three-dimensional environments. This type of migration has been shown to require the expression of the hypoxia-inducible factor 1 alpha (HIF-1α). In this report we demonstrate that Rab25 regulates HIF-1α protein expression in an oxygen independent manner in a panel of cancer cell lines. Regulation of HIF-1α protein expression by Rab25 did not require transcriptional upregulation, but was dependent on de novo protein synthesis through the Erbb2/ERK1/2 and p70S6K/mTOR pathways. Rab25 expression induced HIF-1 transcriptional activity, increased cisplatin resistance, and conferred intraperitoneal growth to the A2780 cell line in immunocompromised mice. Targeting HIF1 activity by silencing HIF-1β re-sensitised cells to cisplatin in vitro and reduced tumour formation of A2780-Rab25 expressing cells in vivo in a mouse ovarian peritoneal carcinomatosis model. Similar effects on cisplatin resistance in vitro and intraperitoneal tumourigenesis in vivo were obtained after HIF1b knockdown in the ovarian cancer cell line SKOV3, which expresses endogenous Rab25 and HIF-1α at atmospheric oxygen concentrations. Our results suggest that Rab25 tumourigenic potential and chemoresistance relies on HIF1 activity in aggressive and metastatic ovarian cancer. Targeting HIF-1 activity may potentially be effective either alone or in combination with standard chemotherapy for aggressive metastatic ovarian cancer

Cucurbit [7] uril encapsulated cisplatin overcomes resistance to cisplatin induced by Rab25 overexpression in an intraperitoneal ovarian cancer model

Background Ovarian cancer is the most fatal of gynaecological malignancies, usually detected at a late stage with intraperitoneal dissemination. Appropriate preclinical models are needed that recapitulate both the histopathological and molecular features of human ovarian cancer for drug-efficacy analysis. Methods Longitudinal studies comparing cisplatin performance either alone or in a novel cisplatin-based delivery-system, cucurbit[7]uril-encapsulated cisplatin (cisplatin@CB[7]) were performed on subcutaneous (s.c.) and intraperitoneal (i.p.) xenografts using the human ovarian cancer cell line A2780 stably expressing the small GTPase Rab25, which allows A2780 intraperitoneal growth; and luciferase, to allow tumour load measurement by non-invasive bioluminescent imaging. Results Rab25 expression induced cisplatin resistance compared to the parental cell line as assessed by the MTT assay in vitro. These findings did not translate in vivo, where cisplatin resistance was determined by the microenvironment. Subcutaneous xenografts of either parental A2780 or cisplatin-resistant Rab25-expressing A2780 cells presented similar responses to cisplatin treatment. In contrast, increased cisplatin resistance was only detected in i.p. tumours. Treatment of the cisplatin-resistant i.p. model with the novel cisplatin@CB[7] delivery system resulted in a substantial reduction of i.p. tumour load and increased necrosis. Conclusions Poor clinical performance of novel chemotherapeutics might reflect inappropriate preclinical models. Here we present an ovarian i.p. model that recapitulates the histopathological and chemoresistant features of the clinical disease. In addition, we demonstrate that the novel cisplatin-delivery system, cisplatin@CB[7] may have utility in the treatment of drug-resistant ovarian human cancers

Dynamic telomerase gene suppression via network effects of GSK3 inhibition

<b>Background</b>: Telomerase controls telomere homeostasis and cell immortality and is a promising anti-cancer target, but few small molecule telomerase inhibitors have been developed. Reactivated transcription of the catalytic subunit hTERT in cancer cells controls telomerase expression. Better understanding of upstream pathways is critical for effective anti-telomerase therapeutics and may reveal new targets to inhibit hTERT expression. <b>Methodology/Principal Findings</b>: In a focused promoter screen, several GSK3 inhibitors suppressed hTERT reporter activity. GSK3 inhibition using 6-bromoindirubin-3′-oxime suppressed hTERT expression, telomerase activity and telomere length in several cancer cell lines and growth and hTERT expression in ovarian cancer xenografts. Microarray analysis, network modelling and oligonucleotide binding assays suggested that multiple transcription factors were affected. Extensive remodelling involving Sp1, STAT3, c-Myc, NFκB, and p53 occurred at the endogenous hTERT promoter. RNAi screening of the hTERT promoter revealed multiple kinase genes which affect the hTERT promoter, potentially acting through these factors. Prolonged inhibitor treatments caused dynamic expression both of hTERT and of c-Jun, p53, STAT3, AR and c-Myc. <b>Conclusions/Significance</b>: Our results indicate that GSK3 activates hTERT expression in cancer cells and contributes to telomere length homeostasis. GSK3 inhibition is a clinical strategy for several chronic diseases. These results imply that it may also be useful in cancer therapy. However, the complex network effects we show here have implications for either setting

Cucurbit[7]uril encapsulated cisplatin overcomes cisplatin resistance via a pharmacokinetic effect

The cucurbit[n]uril (CB[n]) family of macrocycles has been shown to have potential in drug delivery where they are able to provide physical and chemical stability to drugs, improve drug solubility, control drug release and mask the taste of drugs. Cisplatin is a small molecule platinum-based anticancer drug that has severe dose-limiting side-effects. Cisplatin forms a host–guest complex with cucurbit[7]uril (cisplatin@CB[7]) with the platinum atom and both chlorido ligands located inside the macrocycle, with binding stabilised by four hydrogen bonds (2.15–2.44 A ˚ ). Whilst CB[7] has no effect on the in vitro cytotoxicity of cisplatin in the human ovarian carcinoma cell line A2780 and its cisplatin-resistant sub-lines A2780/cp70 and MCP1, there is a significant effect on in vivo cytotoxicity using human tumour xenografts. Cisplatin@CB[7] is just as effective on A2780 tumours compared with free cisplatin, and in the cisplatin-resistant A2780/cp70 tumours cisplatin@CB[7] markedly slows tumour growth. The ability of cisplatin@CB[7] to overcome resistance in vivo appears to be a pharmacokinetic effect. Whilst the peak plasma level and tissue distribution are the same for cisplatin@CB[7] and free cisplatin, the total concentration of circulating cisplatin@CB[7] over a period of 24 hours is significantly higher than for free cisplatin when administered at the equivalent dose. The results provide the first example of overcoming drug resistance via a purely pharmacokinetic effect rather than drug design or better tumour targeting, and demonstrate that in vitro assays are no longer as important in screening advanced systems of drug delivery

Quantifying public preferences for different bowel preparation options prior to screening CT colonography: a discrete choice experiment

Objectives: CT colonography (CTC) may be an acceptable test for colorectal cancer screening but bowel preparation can be a barrier to uptake. This study tested the hypothesis that prospective screening invitees would prefer full-laxative preparation with higher sensitivity and specificity for polyps, despite greater burden, over less burdensome reduced-laxative or non-laxative alternatives with lower sensitivity and specificity. Design: Discrete choice experiment. Setting: Online, web-based survey. Participants: 2819 adults (45–54 years) from the UK responded to an online invitation to take part in a cancer screening study. Quota sampling ensured that the sample reflected key demographics of the target population and had no relevant bowel disease or medical qualifications. The analysis comprised 607 participants. Interventions: After receiving information about screening and CTC, participants completed 3–4 choice scenarios. Scenarios showed two hypothetical forms of CTC with different permutations of three attributes: preparation, sensitivity and specificity for polyps. Primary outcome measures: Participants considered the trade-offs in each scenario and stated their preferred test (or chose neither). Results: Preparation and sensitivity for polyps were both significant predictors of preferences (coefficients: −3.834 to −6.346 for preparation, 0.207–0.257 for sensitivity; p<0.0005). These attributes predicted preferences to a similar extent. Realistic specificity values were non-significant (−0.002 to 0.025; p=0.953). Contrary to our hypothesis, probabilities of selecting tests were similar for realistic forms of full-laxative, reduced-laxative and non-laxative preparations (0.362–0.421). However, they were substantially higher for hypothetical improved forms of reduced-laxative or non-laxative preparations with better sensitivity for polyps (0.584–0.837). Conclusions: Uptake of CTC following non-laxative or reduced-laxative preparations is unlikely to be greater than following full-laxative preparation as perceived gains from reduced burden may be diminished by reduced sensitivity. However, both attributes are important so a more sensitive form of reduced-laxative or non-laxative preparation might improve uptake substantially.JRC.I.2-Public Health Policy Suppor

Cisplatin drug delivery using gold-coated iron oxide nanoparticles for enhanced tumour targeting with external magnetic fields

The platinum-based chemotherapeutic drug cisplatin is highly effective in the treatment of solid tumours, but its use is restricted by poor bioavailability, severe dose-limiting side effects and rapid development of drug resistance. In light of this we have tethered the active component of cisplatin to goldcoated iron oxide nanoparticles to improve its delivery to tumours and increase its efficacy. Iron oxide nanoparticles (FeNPs) were synthesised via a co-precipitation method before gold was reduced onto the surface (Au@FeNPs). Aquated cisplatin was used to attach {Pt(NH3)2} to the nanoparticles by a thiolated polyethylene glycol linker forming the desired product (Pt@Au@FeNP). The nanoparticles were characterised by dynamic light scattering, scanning transmission electron microscopy, UV–Vis spectrophotometry, inductively coupled plasma mass spectrometry and electron probe microanalysis. The nanoparticles increase in size as they are constructed, with the synthesised FeNPs having a diameter of 5– 50 nm, which increases to 20–80 nm for the Au@FeNPs, and to 60–120 nm for the Pt@Au@FeNPs. Nanoparticle drug loading was found to be 7.9 10 4 moles of platinum per gram of gold. The FeNPs appear to have little inherent cytotoxicity, whereas the Au@FeNPs are as active as cisplatin in the A2780 and A2780/cp70 cancer cell lines. More importantly the Pt@Au@FeNPs are up to 110-fold more cytotoxic than cisplatin. Finally, external magnets were used to demonstrate that the nanoparticles could be accumulated in specific regions and that cell growth inhibition was localised to those areas

Understanding barriers to involving community midwives in identifying research participants; experience of the first Steps randomised controlled trial

- Objective: To explore barriers to the involvement of community midwives in identifying women in early pregnancy as potential participants in the XX, a randomised controlled trial of a new intervention to provide health and parenting support to potentially vulnerable women. - Design: Descriptive qualitative investigation using semi-structured audio-recoded interviews. - Setting: Community midwifery offices. - Participants: Volunteer sample of 13 community midwives. - Measurement: Themes derived from content analysis. - Findings: Understanding of their role in the research process was unclear to many midwives. Confusion arose about the difference between potential participant identification and trial recruitment. There were concerns about the eligibility criteria and it was suggested that there was insufficient time during booking appointments, and sometimes insufficient information, to determine potential eligibility. Midwives had concerns about some aspects of the intervention, which incorporated routine midwifery care, and had expectations that women may not like a group programme. This may have led some not to mention the trial. They were, however positive about the programme's potential for beneficial impacts on mothers and infants. - Key conclusions: Dedicated research midwives may be the best option if research studies need to identify potential participants early in pregnancy, so that they can communicate with all their colleagues. - Implications for practice: If community midwives are asked to be involved in time-critical research they are likely to need additional local resources and support