The interplay between MDM2 and PSMA in metastatic breast cancer cells

Both mouse double minute (MDM2) and prostate-specific membrane antigen (PSMA) are known to be associated with the progressive properties of cancer. Moreover, overexpression of both molecules has been implicated in an increase in the proliferation, migration and invasion of tumour cells. MDM2 is a negative regulator of tumour suppressor of p53 but also is known to play multiple p53-independent roles in many cancer types. PSMA was originally thought to be solely expressed in prostate tissues and overexpression prostatic cancers; however, recently its expression was reported in various other solid tumours, including those of the breast. Our work showed a possible link between these proteins following knockdown of each molecule in breast cancer cell lines, ZR-75.1 and MDA-MB-231, with targeted siRNA molecules. A decrease of MDM2 and PSMA led to a decrease in the proliferative, adhesive, migratory and invasive capacities of the cell lines. Additionally, knockdown of MDM2 and PSMA led to similar changes in secretion of matrix metalloproteinases (MMPs), with decreases in MMP2 and MMP8 being seen from both breast cell lines investigated. It was then seen that a link between the two protein could be mediated through the phosphorylation status of serine 473 on protein kinase B (AKT). PSMA knockdown in both breast cancer cell lines led to a decrease of AKT phosphorylation and thus a decrease in MDM2 serine 188. Additionally, it was found that MDM2 siRNA leads to an increase in c-JUN serine 63 phosphorylation, and that PSMA siRNA can lead to an increase at the same site, depending on the cell line. These results indicate that MDM2, AKT and PSMA may represent a new pathway which could be targeted for therapy for breast tumours and perhaps other types of cancer

MicroRNA-7 suppresses the homing and migration potential of human endothelial cells to highly metastatic human breast cancer cells

background: MicroRNA-7 (miR-7) has been observed as a potent tumour suppressor in multiple cancer types including breast cancer. The aim of this study was to investigate the response sensitivities of metastatic breast cancer cells to miR-7 and the roles of miR-7 in the interaction of endothelial cells and metastatic cancer cells. methods: Expression profile of miRNAs in a breast cancer specimen cohort and breast cancer cells were determined using real-time quantitative miRNA assays. Effect of the altering expression of miR-7 on migration, invasion, proliferation, interaction and underlying molecular mechanism of breast cancer cells and endothelial cells was investigated after treatment with the synthesised mimic of miR-7. Luciferase activity analysis was performed to validate Wave-3 as a novel target of miR-7. results: miR-7 expression was negatively correlated with the stage, grade and survival of the breast cancer patients. There was also differential expression of miRNAs including miR-7 in the breast cancer cells. The synthesised mimic of miR-7 inhibits the motility and wound healing potential of breast cancer cells. The highly metastatic MDA-MB-231 cells are more sensitive to the miR-7 treatment than the poorly invasive MCF-7 cells. Treatment with miR-7 downregulated the expression of EGFR, IGF1R and Wave3 in MDA-MB-231 cells but not in MCF-7 cells. In addition, we further demonstrated that miR-7 inhibited the proliferation, migration and invasion of endothelial cells. And more importantly, miR-7 suppressed the homing and migration of endothelial cells to more aggressive tumour cell conditions. conclusions: Given the dual inhibitory effect of miR-7 on metastatic breast cancer cells alone and the interaction of endothelial cells with the tumour-conditioned microenvironment, we suggest miR-7 may be a new therapeutic candidate for its capacity not only to prevent breast cancer cell spreading but also to inhibit tumour-associated angiogenesis in the metastatic breast cancer

Endangered Archaeology in the Middle East and North Africa: Introducing the EAMENA Project

This project uses satellite imagery and historic aerial photographs to discover and interpret archaeological sites. It has created an open access database of archaeological records that provides basic information so that the sites can be better under- stood and preserved in the future. The threats to sites in the Middle East and North Africa are increasing and creating a record of previously unrecorded sites using this methodology may be our the last chance before they are destroyed

Endangered Archaeology in the Middle East and North Africa: Introducing the EAMENA Project

This project uses satellite imagery and historic aerial photographs to discover and interpret archaeological sites. It has created an open access database of archaeological records that provides basic information so that the sites can be better under- stood and preserved in the future. The threats to sites in the Middle East and North Africa are increasing and creating a record of previously unrecorded sites using this methodology may be our the last chance before they are destroyed

The clinical and therapeutic uses of MDM2 and PSMA and their potential interaction in aggressive cancers

Prostate-specific membrane antigen (PSMA) overexpression is observed in the neovasculature of solid tumors, but not in the vasculature of normal tissues. Increased PSMA expression is positively associated with tumor stage and grade, although its function in cancer remains unclear. Mouse double minute 2 (MDM2) is a negative regulator of the p53 tumor suppressor and is reported to regulate VEGF expression and angiogenesis. Both proteins have been considered as biomarkers and therapeutic targets for advanced solid tumors. Our work and a recent microarray-based gene profiling study suggest there could be signaling interplay between MDM2 and PSMA. We herein review the mechanisms underlining the outgrowth of tumors associated with PSMA and MDM2, their potential interaction and how this may be applied to anticancer therapeutics

Uptake and transport of B12-conjugated nanoparticles in airway epithelium

Non-invasive delivery of biotherapeutics, as an attractive alternative to injections, could potentially be achieved through the mucosal surfaces, utilizing nanoscale therapeutic carriers. However, nanoparticles do not readily cross the mucosal barriers,with the epitheliumpresenting a major barrier to their translocation. The transcytotic pathway of vitamin B12 has previously been shown to ‘ferry’ B12-decorated nanoparticles across intestinal epithelial (Caco-2) cells. However, such studies have not been reported for the airway epithelium. Furthermore, the presence in the airways of the cell machinery responsible for transepithelial trafficking of B12 is not widely reported. Using a combination of molecular biology and immunostaining techniques, our work demonstrates that the bronchial cell line, Calu-3, expresses the B12-intrinsic factor receptor, the transcobalamin II receptor and the transcobalamin II carrier protein. Importantly, the work showed that sub-200 nm model nanoparticles chemically conjugated to B12 were internalised and transported across the Calu-3 cell layers,with B12 conjugation not only enhancing cell uptake and transepithelial transport, but also influencing intracellular trafficking. Our work therefore demonstrates that the B12 endocytotic apparatus is not only present in this airway model, but also transports ligand-conjugated nanoparticles across polarised epithelial cells, indicating potential for B12-mediated delivery of nanoscale carriers of biotherapeutics across the airways

Treatment of Rat Spinal Cord Injury with the Neurotrophic Factor Albumin-Oleic Acid: Translational Application for Paralysis, Spasticity and Pain

Sensorimotor dysfunction following incomplete spinal cord injury (iSCI) is often characterized by the debilitating symptoms of paralysis, spasticity and pain, which require treatment with novel pleiotropic pharmacological agents. Previous in vitro studies suggest that Albumin (Alb) and Oleic Acid (OA) may play a role together as an endogenous neurotrophic factor. Although Alb can promote basic recovery of motor function after iSCI, the therapeutic effect of OA or Alb-OA on a known translational measure of SCI associated with symptoms of spasticity and change in nociception has not been studied. Following T9 spinal contusion injury in Wistar rats, intrathecal treatment with: i) Saline, ii) Alb (0.4 nanomoles), iii) OA (80 nanomoles), iv) Alb-Elaidic acid (0.4/80 nanomoles), or v) Alb-OA (0.4/80 nanomoles) were evaluated on basic motor function, temporal summation of noxious reflex activity, and with a new test of descending modulation of spinal activity below the SCI up to one month after injury. Albumin, OA and Alb-OA treatment inhibited nociceptive Tibialis Anterior (TA) reflex activity. Moreover Alb-OA synergistically promoted early recovery of locomotor activity to 50±10% of control and promoted de novo phasic descending inhibition of TA noxious reflex activity to 47±5% following non-invasive electrical conditioning stimulation applied above the iSCI. Spinal L4–L5 immunohistochemistry demonstrated a unique increase in serotonin fibre innervation up to 4.2±1.1 and 2.3±0.3 fold within the dorsal and ventral horn respectively with Alb-OA treatment when compared to uninjured tissue, in addition to a reduction in NR1 NMDA receptor phosphorylation and microglia reactivity. Early recovery of voluntary motor function accompanied with tonic and de novo phasic descending inhibition of nociceptive TA flexor reflex activity following Alb-OA treatment, mediated via known endogenous spinal mechanisms of action, suggests a clinical application of this novel neurotrophic factor for the treatment of paralysis, spasticity and pain

MDM2 and PSMA play inhibitory roles in metastatic breast cancer cells through regulation of matrix metalloproteinases

Mouse double minute 2 (MDM2) and prostate-specific membrane antigen (PSMA) are currently under investigation as individual therapeutic targets due to their overexpression in many cancer types, as well as their pro-tumorigenic effect on cells. Recently, knockdown of PSMA was linked to a decrease in MDM2 and matrix metalloproteinase 2 (MMP2) and an increase in MMP3 and MMP13 expression. We aimed to assess the link between PSMA, MDM2 and the MMPs in metastatic breast cancer cell lines. MATERIALS AND METHODS: Real-time quantitative polymerase chain reaction (PCR) and western blotting were used to assess siRNA-mediated knockdown of MDM2 and PSMA in MDA-MB-231 and ZR-75.1 breast cancer cells. Assays to assess the growth, adhesion, migration and invasion of the cells following siRNA treatment were undertaken. MMP and tissue inhibitor of matrix metalloproteinases (TIMP) levels were assessed via quantitative PCR. RESULTS: Knockdown of MDM2 resulted in a decrease in PSMA expression levels and vice versa; although this trend was not replicated at the protein level. Knockdown of each of the molecules resulted in a decrease in growth, adhesion, migration and invasive ability of breast cancer cells. Both knockdowns led to a decrease in MMP2 and an increase in MMP3, -10 and -13 gene expression. CONCLUSION: MDM2 and PSMA may co-regulate the expression of certain MMPs and, thus, the functionality of cells in metastatic breast cancer