A novel protein isoform of the RON tyrosine kinase receptor transforms human pancreatic duct epithelial cells.

The MST1R gene is overexpressed in pancreatic cancer producing elevated levels of the RON tyrosine kinase receptor protein. While mutations in MST1R are rare, alternative splice variants have been previously reported in epithelial cancers. We report the discovery of a novel RON isoform discovered in human pancreatic cancer. Partial splicing of exons 5 and 6 (P5P6) produces a RON isoform that lacks the first extracellular immunoglobulin-plexin-transcription domain. The splice variant is detected in 73% of xenografts derived from pancreatic adenocarcinoma patients and 71% of pancreatic cancer cell lines. Peptides specific to RON P5P6 detected in human pancreatic cancer specimens by mass spectrometry confirm translation of the protein isoform. The P5P6 isoform is found to be constitutively phosphorylated, present in the cytoplasm, and it traffics to the plasma membrane. Expression of P5P6 in immortalized human pancreatic duct epithelial (HPDE) cells activates downstream AKT, and in human pancreatic epithelial nestin-expressing cells, activates both the AKT and MAPK pathways. Inhibiting RON P5P6 in HPDE cells using a small molecule inhibitor BMS-777607 blocked constitutive activation and decreased AKT signaling. P5P6 transforms NIH3T3 cells and induces tumorigenicity in HPDE cells. Resultant HPDE-P5P6 tumors develop a dense stromal compartment similar to that seen in pancreatic cancer. In summary, we have identified a novel and constitutively active isoform of the RON tyrosine kinase receptor that has transforming activity and is expressed in human pancreatic cancer. These findings provide additional insight into the biology of the RON receptor in pancreatic cancer and are clinically relevant to the study of RON as a potential therapeutic target

Carrageenan Is a Potent Inhibitor of Papillomavirus Infection

Certain sexually transmitted human papillomavirus (HPV) types are causally associated with the development of cervical cancer. Our recent development of high-titer HPV pseudoviruses has made it possible to perform high-throughput in vitro screens to identify HPV infection inhibitors. Comparison of a variety of compounds revealed that carrageenan, a type of sulfated polysaccharide extracted from red algae, is an extremely potent infection inhibitor for a broad range of sexually transmitted HPVs. Although carrageenan can inhibit herpes simplex viruses and some strains of HIV in vitro, genital HPVs are about a thousand-fold more susceptible, with 50% inhibitory doses in the low ng/ml range. Carrageenan acts primarily by preventing the binding of HPV virions to cells. This finding is consistent with the fact that carrageenan resembles heparan sulfate, an HPV cell-attachment factor. However, carrageenan is three orders of magnitude more potent than heparin, a form of cell-free heparan sulfate that has been regarded as a highly effective model HPV inhibitor. Carrageenan can also block HPV infection through a second, postattachment heparan sulfate–independent effect. Carrageenan is in widespread commercial use as a thickener in a variety of cosmetic and food products, ranging from sexual lubricants to infant feeding formulas. Some of these products block HPV infectivity in vitro, even when diluted a million-fold. Clinical trials are needed to determine whether carrageenan-based products are effective as topical microbicides against genital HPVs

Cross-neutralization of cutaneous and mucosal Papillomavirus types with anti-sera to the amino terminus of L2

AbstractVaccination with papillomavirus L2 has been shown to induce neutralizing antibodies that protect against homologous type infection and cross-neutralize a limited number of genital HPVs. Surprisingly, we found that antibodies to bovine papillomavirus (BPV1) L2 amino acids 1–88 induced similar titers of neutralizing antibodies against Human papillomavirus (HPV)16 and 18 and BPV1 pseudoviruses and also neutralized HPV11 native virions. These antibodies also neutralized each of the other pseudovirus types tested, HPV31, HPV6 and Cottontail rabbit papillomavirus (CRPV) pseudoviruses, albeit with lower titers. HPV16, HPV18, HPV31, HPV6 and CRPV L2 anti-sera also displayed some cross-neutralization, but the titers were lower and did not encompass all pseudoviruses tested. This study demonstrates the presence of broadly cross-neutralizing epitopes at the N-terminus of L2 that are shared by cutaneous and mucosal types and by types that infect divergent species. BPV1 L2 was exceptionally effective at inducing cross-neutralizing antibodies to these shared epitopes

p120Ras-GAP binds the DLC1 Rho-GAP tumor suppressor protein and inhibits its RhoA GTPase and growth-suppressing activities

DLC1, which encodes a Rho GTPase activating protein (Rho-GAP), is a potent tumor suppressor gene that is frequently inactivated in several human cancers. DLC-1 is a multidomain protein that has been shown previously to bind members of the tensin gene family. Here we show that p120Ras-GAP (Ras-GAP; also known as RASA1) interacts and extensively colocalizes with DLC1 in focal adhesions. The binding was mapped to the SH3 domain located in the N-terminus of Ras-GAP and to the RhoGAP catalytic domain, located in the C-terminus of the DLC1. In vitro analyses with purified proteins determined that the isolated Ras-GAP SH3 domain inhibits DLC1 RhoGAP activity, suggesting that Ras-GAP is a negative regulator of DLC1 RhoGAP activity. Consistent with this possibility, we found that ectopic overexpression of Ras-GAP in a Ras-GAP-insensitive tumor line impaired the growth suppressing activity of DLC1 and increased RhoA activity in vivo. Our observations expand the complexity of proteins that regulate DLC1 function and define a novel mechanism of the cross-talk between Ras and Rho GTPases

Specific antibody levels at the cervix during the menstrual cycle of women vaccinated with human papillomavirus 16 virus-like particles

BACKGROUND: In early-phase trials, a human papillomavirus 16 (HPV16) virus-like particle (VLP) vaccine has been shown to be well tolerated, immunogenic, and protective against HPV16 in women, most of whom were taking oral contraceptives. Previous studies have not determined whether HPV immunization results in specific antibody levels in the human genital tract or whether these levels might vary during contraceptive or ovulatory cycles. Therefore, we determined the levels of total and specific antibodies in the cervical secretions of women who had been immunized with HPV16 VLPs and examined the influence of the menstrual cycle and oral contraceptive use on these levels. METHODS: Two groups of women were immunized, seven who were taking oral contraceptives and 11 who were ovulating. After seroconversion, serum and cervical secretions were collected twice weekly for 5 weeks. Total immunoglobulins (IgG and IgA) and vaccine-specific IgGs were determined by enzyme-linked immunosorbent assay. Nonparametric statistical analyses were used to determine the statistical significance of differences in IgG levels between groups, and correlations between serum- and cervical-specific IgG levels were determined by the Spearman correlation coefficient. RESULTS: All participants developed detectable titers of anti-HPV16 VLP IgGs in their cervical secretions after immunization. The cervical titers of specific IgG and total IgGs and IgAs among participants in the contraceptive group were relatively constant throughout the contraceptive cycle. In contrast, the cervical titers of specific IgG and total IgGs and IgAs among participants in the ovulatory group varied during the menstrual cycle, being highest during the proliferative phase, decreasing approximately ninefold around ovulation, and increasing approximately threefold during the luteal phase. Serum- and cervical-specific IgG levels were correlated (r =.86) in women in the contraceptive group but not in women in the ovulatory group (r =.27). CONCLUSIONS: The relatively high titer of anti-HPV16 antibodies at the cervix is promising in terms of vaccine efficacy; however, the decrease in antibody titer around ovulation raises the possibility that the HPV16 VLP vaccine might be less effective during the peri-ovulatory phase

Opening up the Pandora's box of sustainability league tables of universities: a Kafkaesque perspective

The aim of this paper is to explore the institutional impact of sustainability league tables on current university agendas. It focuses on a narrative critique of one such league table, the UK's ‘Green League Table', compiled and reported by the student campaigning NGO, ‘People & Planet’ annually between 2007 and 2013. Through a Kafkaesque perspective, this paper offers the proposition that such league tables could be acting as an institutional hegemonic mechanism for social legitimacy, through the desire by universities to show that environmental issues are effectively under control. Espoused eco-narratives of the ‘carbon targets imperative’ and ‘engagement' can serve as a form of deception, by merely embracing the narrative as a rhetorical device. Moreover, they can serve the exclusive, particularistic self-interests of a growing legion of ‘carbon managers’, ‘sustainability managers’ and ‘environmental managers' in satisfying the neo-liberal institutional drive from their vice chancellors

Targeting LIF-mediated paracrine interaction for pancreatic cancer therapy and monitoring.

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis largely owing to inefficient diagnosis and tenacious drug resistance. Activation of pancreatic stellate cells (PSCs) and consequent development of dense stroma are prominent features accounting for this aggressive biology1,2. The reciprocal interplay between PSCs and pancreatic cancer cells (PCCs) not only enhances tumour progression and metastasis but also sustains their own activation, facilitating a vicious cycle to exacerbate tumorigenesis and drug resistance3-7. Furthermore, PSC activation occurs very early during PDAC tumorigenesis8-10, and activated PSCs comprise a substantial fraction of the tumour mass, providing a rich source of readily detectable factors. Therefore, we hypothesized that the communication between PSCs and PCCs could be an exploitable target to develop effective strategies for PDAC therapy and diagnosis. Here, starting with a systematic proteomic investigation of secreted disease mediators and underlying molecular mechanisms, we reveal that leukaemia inhibitory factor (LIF) is a key paracrine factor from activated PSCs acting on cancer cells. Both pharmacologic LIF blockade and genetic Lifr deletion markedly slow tumour progression and augment the efficacy of chemotherapy to prolong survival of PDAC mouse models, mainly by modulating cancer cell differentiation and epithelial-mesenchymal transition status. Moreover, in both mouse models and human PDAC, aberrant production of LIF in the pancreas is restricted to pathological conditions and correlates with PDAC pathogenesis, and changes in the levels of circulating LIF correlate well with tumour response to therapy. Collectively, these findings reveal a function of LIF in PDAC tumorigenesis, and suggest its translational potential as an attractive therapeutic target and circulating marker. Our studies underscore how a better understanding of cell-cell communication within the tumour microenvironment can suggest novel strategies for cancer therapy

Distribution and Regulation of the Mobile Genetic Element-Encoded Phenol-Soluble Modulin PSM-mec in Methicillin-Resistant Staphylococcus aureus

The phenol-soluble modulin PSM-mec is the only known staphylococcal toxin that is encoded on a mobile antibiotic resistance determinant, namely the staphylococcal cassette chromosome (SCC) element mec encoding resistance to methicillin. Here we show that the psm-mec gene is found frequently among methicillin-resistant Staphylococcus aureus (MRSA) strains of SCCmec types II, III, and VIII, and is a conserved part of the class A mec gene complex. Controlled expression of AgrA versus RNAIII in agr mutants of all 3 psm-mec-positive SCCmec types demonstrated that expression of psm-mec, which is highly variable, is controlled by AgrA in an RNAIII-independent manner. Furthermore, psm-mec isogenic deletion mutants showed only minor changes in PSMα peptide production and unchanged (or, as previously described, diminished) virulence compared to the corresponding wild-type strains in a mouse model of skin infection. This indicates that the recently reported regulatory impact of the psm-mec locus on MRSA virulence, which is opposite to that of the PSM-mec peptide and likely mediated by a regulatory RNA, is minor when analyzed in the original strain background. Our study gives new insight in the distribution, regulation, and role in virulence of the PSM-mec peptide and the psm-mec gene locus

Environmental Contamination as a Risk Factor for Intra-Household Staphylococcus aureus Transmission

Background The household is a recognized community reservoir for Staphylococcus aureus. This study investigated potential risk factors for intra-household S. aureus transmission, including the contribution of environmental contamination. Methods We investigated intra-household S. aureus transmission using a sample of multiple member households from a community-based case-control study examining risk factors for CA-MRSA infection conducted in Northern Manhattan. During a home visit, index subjects completed a questionnaire. All consenting household members were swabbed, as were standardized environmental household items. Swabs were cultured for S. aureus. Positive isolates underwent further molecular characterization. Intra-household transmission was defined as having identical strains among two or more household members. Multiple logistic regression was used to identify independent risk factors for transmission. Results We enrolled 291 households: 146 index cases, 145 index controls and 687 of their household contacts. The majority of indexes were Hispanic (85%), low income (74%), and female (67%), with a mean age of 31 (range 1–79). The average size of case and control households was 4 people. S. aureus colonized individuals in 62% of households and contaminated the environment in 54% of households. USA300 was the predominant clinical infection, colonizing and environmental strain. Eighty-one households had evidence of intra-household transmission: 55 (38%) case and 26 (18%) control households (P<.01). Environmental contamination with a colonizing or clinical infection strain (aOR: 5.4 [2.9–10.3] P<.01) and the presence of a child under 5 (aOR: 2.3 [1.2–4.5] P = .02) were independently associated with transmission. In separate multivariable models, environmental contamination was associated with transmission among case (aOR 3.3, p<.01) and control households (aOR 27.2, p<.01). Conclusions Environmental contamination with a colonizing or clinical infection strain was significantly and independently associated with transmission in a large community-based sample. Environmental contamination should be considered when treating S. aureus infections, particularly among households with multiple infected members