Ligand-Specific Nano-Contrast Agents Promote Enhanced Breast Cancer CT Detection at 0.5 mg Au.

For many cancer types, being undetectable from early symptoms or blood tests, or often detected at late stages, medical imaging emerges as the most efficient tool for cancer screening. MRI, ultrasound, X-rays (mammography), and X-ray CT (CT) are currently used in hospitals with variable costs. Diagnostic materials that can detect breast tumors through molecular recognition and amplify the signal at the targeting site in combination with state-of-the-art CT techniques, such as dual-energy CT, could lead to a more precise detection and assist significantly in image-guided intervention. Herein, we have developed a ligand-specific X-ray contrast agent that recognizes α5ß1 integrins overexpressed in MDA-MB-231 breast cancer cells for detection of triple (-) cancer, which proliferates very aggressively. In vitro studies show binding and internalization of our nanoprobes within those cells, towards uncoated nanoparticles (NPs) and saline. In vivo studies show high retention of ~3 nm ligand-PEG-S-AuNPs in breast tumors in mice (up to 21 days) and pronounced CT detection, with statistical significance from saline and iohexol, though only 0.5 mg of metal were utilized. In addition, accumulation of ligand-specific NPs is shown in tumors with minimal presence in other organs, relative to controls. The prolonged, low-metal, NP-enhanced spectral-CT detection of triple (-) breast cancer could lead to breakthrough advances in X-ray cancer diagnostics, nanotechnology, and medicine.

Multimedia in improving informed consent for caesarean section: A randomised controlled trial.

BACKGROUND: Multimedia modules have been used as an adjunct to improve patient knowledge and recall for various elective surgical procedures, but have been incompletely evaluated in patients undergoing caesarean section. AIMS: To compare the use of a supplementary multimedia module with written information in improving the informed consent process prior to elective caesarean section. MATERIALS AND METHODS: This was a prospective randomised controlled trial (ACTRN12616000430437). Primary outcomes were knowledge and anxiety scores immediately following the intervention and on the day of surgery. Secondary outcomes were patient satisfaction, length of stay, time to cessation of analgesia, and patient assessment of the consent types. RESULTS: Seventy-five patients completed the study. Both multimedia module and written information groups demonstrated a significant increase in knowledge scores with no difference between the groups. In the multimedia-assisted consent group, scores improved from baseline by +2.31 (P < 0.001) immediately after watching the multimedia module and by +2.41 (P < 0.001) on the day of surgery. In the written information group, scores improved by +1.76 (P < <0.001), and +2.31 (P < 0.001) respectively. There was no adverse impact on anxiety in either group. Patient-reported understanding (92.4% vs 78.5%, P = 0.001), and helpfulness (90.1% vs 73.3%, P = 0.001) was significantly higher in the multimedia module group than in the written information group. The multimedia module was assessed as 'slightly too long' and provided 'slightly too much information'. CONCLUSIONS: Multimedia modules are a valuable adjunct to traditional processes of obtaining informed consent for elective caesarean section and should be offered and made available to patients prior to surgery.

MT4-MMP and EGFR expression levels are key biomarkers for breast cancer patient response to chemotherapy and erlotinib.

BACKGROUND: Triple-negative breast cancers (TNBC) are heterogeneous cancers with poor prognosis. We aimed to determine the clinical relevance of membrane type-4 matrix metalloproteinase (MT4-MMP), a membrane type matrix metalloproteinase that interacts with epidermal growth factor receptor (EGFR) overexpressed in >50% of TNBC. METHODS: We conducted a retrospective immunohistochemical analysis on human TNBC samples (n=81) and validated our findings in in vitro and in vivo assays. RESULTS: Membrane type-4 matrix metalloproteinase and EGFR are produced in 72.5% of TNBC samples, whereas those proteins are faintly produced by healthy tissues. Unexpectedly, tumour relapse after chemotherapy was reduced in samples highly positive for MT4-MMP. Mechanistically, this is ascribed to a higher sensitivity of MT4-MMP-producing cells to alkylating or intercalating chemotherapeutic agents, as assessed in vitro. In sharp contrast, MT4-MMP expression did not affect tumour cell sensitivity to paclitaxel that interferes with protease trafficking. Importantly, MT4-MMP expression sensitised cancer cells to erlotinib, a tyrosine kinase EGFR inhibitor. In a pre-clinical model, the growth of MT4-MMP overexpressing xenografts, but not of control ones, was reduced by epirubicin or erlotinib. The combination of suboptimal drug doses blocked drastically the growth of MT4-MMP-producing tumours. CONCLUSIONS: We demonstrate that MT4-MMP defines a sub-population of TNBC sensitive to a combination of DNA-targeting chemotherapeutic agents and anti-EGFR drugs.

Dynamics of internalization and recycling of the prometastatic membrane type 4 matrix metalloproteinase (MT4-MMP) in breast cancer cells.

Membrane type 4 matrix metalloproteinase (MT4-MMP) [matrix metalloproteinase (MMP) 17] is a GPI-anchored membrane-type MMP expressed on the cell surface of human breast cancer cells. In triple-negative breast cancer cells, MT4-MMP promotes primary tumour growth and lung metastases. Although the trafficking and internalization of the transmembrane membrane type 1 MMP have been extensively investigated, little is known about the regulatory mechanisms of the GPI-anchored MT4-MMP. Here, we investigated the fate and cellular trafficking of MT4-MMP by analysing its homophilic complex interactions, internalization and recycling dynamics as compared with an inert form, MT4-MMP-E249A. Oligomeric and dimeric complexes were analysed by cotransfection of cells with FLAG-tagged or Myc-tagged MT4-MMP in reducing and nonreducing immunoblotting and coimmunoprecipitation experiments. The trafficking of MT4-MMP was studied with an antibody feeding assay and confocal microscopy analysis or cell surface protein biotinylation and western blot analysis. We demonstrate that MT4-MMP forms homophilic complexes at the cell surface, and internalizes in early endosomes, and that some of the enzyme is either autodegraded or recycled to the cell surface. Our data indicate that MT4-MMP is internalized by the clathrin-independent carriers/GPI-enriched early endosomal compartments pathway, a mechanism that differs from that responsible for the internalization of other membrane-type MMP members. Although MT4-MMP localizes with caveolin-1, MT4-MMP internalization was not affected by inhibitors of caveolin-1 or clathrin endocytosis pathways, but was reduced by CDC42 or RhoA silencing with small interfering RNA. We provide a new mechanistic insight into the regulatory mechanisms of MT4-MMP, which may have implications for the design of novel therapeutic strategies for metastatic breast cancer.

EGFR activation and signaling in cancer cells are enhanced by the membrane-bound metalloprotease MT4-MMP.

MT4-MMP (MMP-17) is a glycosylphosphatidyl inositol-anchored matrix metalloprotease expressed on the surface of cancer cells that promotes tumor growth and metastasis. In this report, we identify MT4-MMP as an important driver of cancer cell proliferation through CDK4 activation and retinoblastoma protein inactivation. We also determine a functional link between MT4-MMP and the growth factor receptor EGFR. Mechanistic experiments revealed direct association of MT4-MMP and its positive effects on EGFR phosphorylation in response to TGFα and EGF in cancer cells. Notably, the effects of MT4-MMP on proliferation and EGFR activation did not rely on metalloprotease activity. Clinically, MT4-MMP and EGFR expressions were correlated in human triple-negative breast cancer specimens. Altogether, our results identify MT4-MMP as a positive modifier of EGFR outside-in signaling that acts to cooperatively drive cancer cell proliferation.

Blocking lipid synthesis overcomes tumor regrowth and metastasis after antiangiogenic therapy withdrawal.

The molecular mechanisms responsible for the failure of antiangiogenic therapies and how tumors adapt to these therapies are unclear. Here, we applied transcriptomic, proteomic, and metabolomic approaches to preclinical models and provide evidence for tumor adaptation to vascular endothelial growth factor blockade through a metabolic shift toward carbohydrate and lipid metabolism in tumors. During sunitinib or sorafenib treatment, tumor growth was inhibited and tumors were hypoxic and glycolytic. In sharp contrast, treatment withdrawal led to tumor regrowth, angiogenesis restoration, moderate lactate production, and enhanced lipid synthesis. This metabolic shift was associated with a drastic increase in metastatic dissemination. Interestingly, pharmacological lipogenesis inhibition with orlistat or fatty acid synthase downregulation with shRNA inhibited tumor regrowth and metastases after sunitinib treatment withdrawal. Our data shed light on metabolic alterations that result in cancer adaptation to antiangiogenic treatments and identify key molecules involved in lipid metabolism as putative therapeutic targets.