STAT3 in tumor fibroblasts promotes an immunosuppressive microenvironment in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is associated with an incredibly dense stroma, which contributes to its recalcitrance to therapy. Cancer-associated fibroblasts (CAFs) are one of the most abundant cell types within the PDAC stroma and have context-dependent regulation of tumor progression in the tumor microenvironment (TME). Therefore, understanding tumor-promoting pathways in CAFs is essential for developing better stromal targeting therapies. Here, we show that disruption of the STAT3 signaling axis via genetic ablation of Stat3 in stromal fibroblasts in a Kras G12D PDAC mouse model not only slows tumor progression and increases survival, but re-shapes the characteristic immune-suppressive TME by decreasing M2 macrophages (F480+CD206+) and increasing CD8+ T cells. Mechanistically, we show that loss of the tumor suppressor PTEN in pancreatic CAFs leads to an increase in STAT3 phosphorylation. In addition, increased STAT3 phosphorylation in pancreatic CAFs promotes secretion of CXCL1. Inhibition of CXCL1 signaling inhibits M2 polarization in vitro. The results provide a potential mechanism by which CAFs promote an immune-suppressive TME and promote tumor progression in a spontaneous model of PDAC.

OP0136 RITUXIMAB PREVENTS THE PROGRESSION OF B-CELL DRIVEN INFLAMMATORY INFILTRATE IN THE MINOR SALIVARY GLANDS OF PRIMARY SJOGREN’S SYNDROME BY DOWNREGULATING IMMUNOLOGICAL PATHWAYS KEY IN ECTOPIC GERMINAL CENTRE ORGANIZATION: RESULTS FROM THE TRACTISS TRIAL

Background:

The pathogenic role of B-cells in primary Sjögren’s Syndrome (pSS) is well established and B cell abnormalities. Because of the substantial role of B-cells, rituximab (RTX), a chimeric anti-CD20 monoclonal antibody, has been considered as a potential biologic disease modifying drug to reduce disease activity in pSS. To date, the TRial for Anti-B-Cell Therapy In patients with pSS (TRACTISS) is the largest multi-centre, placebo-controlled trial with RTX. Despite the unmet primary endpoints (30% reduction in fatigue or oral dryness, measured by visual analogue scale), RTX treated patients showed an improvement in unstimulated whole salivary flow (Bowman et al. Arthritis Rheumatol 2017;69:1440–1450).

Objectives:

To provide the first longitudinal transcriptomic and histological analysis at 3 time points over 48 weeks of labial SGs of pSS patients treated with RTX, in comparison to placebo, from the TRACTISS cohort.

Methods:

26 pSS patients randomised to RTX or placebo arm consented for labial SG biopsies at baseline, weeks 16 and 48. Patients received two 1000mg cycles of RTX or placebo at baseline and week 24. SG focus score, inflammatory aggregate area fraction, B-cells (CD20+), T-cells (CD3+), follicular dendritic cells (FDCs) (CD21+) and plasma cells (CD138+) density were assessed by H&E and immunofluorescence staining. The histological analysis was performed by digital imaging using QuPath software. RNA was extracted from matched labial SG lobules and sequenced with Illumina platform. A Principal Component Analysis (PCA) and features driving the PCA were investigated along with the most influential gene loadings. The limma-voom R pipeline was used to extract Differential Expressed Genes (DEGs) between placebo and RTX group at week 48, and gene ontology (GO) enrichment analysis performed through EnrichR to derive GO terms and pathways associated with DEGs.

Results:

Placebo-treated labial SGs showed a worsening of inflammation highlighted by the increment of B-cell density, development of new FDC networks, and a higher ectopic GC prevalence at week 48, compared to RTX-treated patients. No difference in total T-cells and plasma cell infiltration was observed. RTX downregulated genes involved in immune cell recruitment and inflammatory aggregate organisation (e.g. CCR7, CCL19, CD52, and PDCD1) and gene signature-based analysis of 64 immune cell types highlighted how RTX preferentially blocked class-switched- and memory-B-cells infiltration in SGs at week 48. Pathway analyses confirmed the downregulation of leukocyte migration, MHC class II antigen presentation, and T-cell co-stimulation immunological pathways, such as the CD40 receptor complex pathway. The analysis of placebo SGs transcriptomic at week 48 showed a higher expression of genes linked to ectopic GC organisation, such as CXCL13, CCL19, LTβ, in female compared to male subjects. Gender was confirmed as a key co-variate responsible for most of the variation in the PCA, together with the SG focus score and the foci area fraction.

Conclusion:

Treatment with RTX showed beneficial effects on labial SG inflammatory infiltration in pSS, by downregulating genes involved in immune cell recruitment, activation and organisation in ectopic GCs. Class-switched-B-cells, memory-B-cells and FDC network development were primarily affected appearing to be responsible for the lack of progression in SG B cell infiltration in the RTX compared to the placebo arm in which clear worsening of SG immunopathology over 48 weeks was detected in female patients. Although a clear association with the clinical improvement in unstimulated salivary flow observed at week 48 in RTX-treated patients could not be established given the low number of patients consenting to 3 longitudinal biopsies it is conceivable that RTX is responsible for preserving exocrine function.

Acknowledgements:

SJB receives a salary contribution from the NIHR Birmingham Biomedical Research Centre.

Disclosure of Interests:

Elena Pontarini: None declared, Farzana Chowdhury: None declared, Elisabetta Sciacca: None declared, Sofia Grigoriadou: None declared, Felice Rivellese: None declared, Davide Lucchesi: None declared, Katriona Goldmann: None declared, Liliane Fossati-Jimack: None declared, Paul Emery: None declared, Wan Fai Ng: None declared, Nurhan Sutcliffe: None declared, Colin Everett: None declared, Catherine Fernandez: None declared, Anwar Tappuni: None declared, Myles Lewis: None declared, Costantino Pitzalis: None declared, Simon J. Bowman Consultant of: SJB In 2020 I have received consultancy fees from Novartis, Abbvie and Galapagos., Michele Bombardieri: None declared

Cross-sectional analysis of US scope of practice laws and employed physician assistants

OBJECTIVE

This study examined if the variation in physician assistant (PA) state scope of practice (SOP) laws across states are associated with number of employed PAs, PA demographics and PA/population ratio per state. The hypothesis was that less restrictive SOP laws will increase the demand for PAs and the number of PAs in a state.

DESIGN

Retrospective cross-sectional analysis at three time points: 1998, 2008, 2017.

SETTING

Fifty states and the District of Columbia.

PARTICIPANTS

Employed PAs in 1998, 2008, 2017.

METHODS

SOP laws were categorised as permissive, average and restrictive. Three national datasets were combined to allow for descriptive analysis of employed PAs by year and SOP categories. We used linear predictive models to generate and compare PA/population ratio least square means by SOP categories for each year. Models were adjusted for percent female PA and PAs mean age.

RESULTS

There was a median PA/population ratio of 23 per 100 000 population in 1998 and 33 in 2017. A heterogeneous expansion of SOP laws was seen with 17 states defined as super expanders while 15 were never adopters. In 2017, comparing restrictive to permissive states showed that in adjusted models permissive SOP laws were associated with 11.7 (p .03) increase in ratio of employed PAs per 100 000 population, demonstrating that states with permissive SOP laws have an increased PA density.

CONCLUSIONS

There has been steady growth in the mean PA/population ratio since the turn of the century. At the same time, PA SOP laws in the USA have expanded, with just 10 states remaining in the restrictive category. Permissive SOP laws are associated with an increase in the ratio of employed PAs per state population. As states work to meet the projected physician need, SOP expansion may be an important policy consideration to increase the PA workforce.

A comparative linkage map of oilseed rape and its use for QTL analysis of seed oil and erucic acid content

We have developed a new DH mapping population for oilseed rape, named TNDH, using genetically and phenotypically diverse parental lines. We used the population in the construction of a high stringency genetic linkage map, consisting of 277 loci, for use in quantitative genetic analysis. A proportion of the markers had been used previously in the construction of linkage maps for Brassica species, thus permitting the alignment of maps. The map includes 68 newly developed Sequence Tagged Site (STS) markers targeted to the homologues of defined genes of A. thaliana. The use of these markers permits the alignment of our linkage map with the A. thaliana genome sequence. An additional 74 loci (31 newly developed STS markers and 43 loci defined by SSR and RFLP markers that had previously been used in published linkage maps) were added to the map. These markers increased the resolution of alignment of the newly constructed linkage map with existing Brassica linkage maps and the A. thaliana genome sequence. We conducted field trials with the TNDH population at two sites, and over 2 years, and identified reproducible QTL for seed oil content and erucic acid content. The results provide new insights into the genetic control of seed oil and erucic acid content in oilseed rape, and demonstrate the utility of the linkage map and population.

A comparison of transgenic barley lines produced by particle bombardment and Agrobacterium-mediated techniques

Two barley transformation systems, Agrobacterium-mediated and particle bombardment, were compared in terms of transformation efficiency, transgene copy number, expression, inheritance and physical structure of the transgenic loci using fluorescence in situ hybridisation (FISH). The efficiency of Agrobacterium-mediated transformation was double that obtained with particle bombardment. While 100% of the Agrobacterium-derived lines integrated between one and three copies of the transgene, 60% of the transgenic lines derived by particle bombardment integrated more than eight copies of the transgene. In most of the Agrobacterium-derived lines, the integrated T-DNA was stable and inherited as a simple Mendelian trait. Transgene silencing was frequently observed in the T1 populations of the bombardment-derived lines. The FISH technique was able to reveal additional details of the transgene integration site. For the efficient production of transgenic barley plants, with stable transgene expression and reduced silencing, the Agrobacterium-mediated method appears to offer significant advantages over particle bombardment.

Buprenorphine given after surgery does not alter renal ischemia/reperfusion injury

BACKGROUND AND PURPOSE

Potential drugs for human acute renal failure are often tested in an animal model of renal ischemia/reperfusion injury. Analgesics are often not given after surgery because of concerns that they would alter renal function. Therefore, we tested whether postoperative analgesia would alter animal health or affect the degree of renal injury.

METHODS

Mice were subjected to either 32 or 37 minutes of renal ischemia, given two or six doses of buprenorphine or vehicle at 12-hour intervals, and followed for 72 hours. In some animals, we measured body temperature and physical activity by use of telemetry.

RESULTS

Animals treated with buprenorphine recovered more rapidly from surgery based on postoperative activity, and had a small but not significant tendency for faster restoration of normal body temperature. Animals treated with buprenorphine had less weight loss after 37 minutes of ischemia. Buprenorphine given after surgery did not influence the degree of renal injury after ischemia/reperfusion.

CONCLUSIONS

Buprenorphine should be given after renal ischemia-reperfusion surgery because administration of the proper analgesic improved animal health without interfering with the renal ischemia/reperfusion model. Analgesic treatment at the time of the operation and 12 hours after was sufficient. Buprenorphine may reduce the post-surgical stress response, and thus potentially improve the specificity of testing for drugs that reduce or treat renal injury.

Growth, adipose, brain, and skin alterations resulting from targeted disruption of the mouse peroxisome proliferator-activated receptor beta(delta)

To determine the physiological roles of peroxisome proliferator-activated receptor beta (PPARbeta), null mice were constructed by targeted disruption of the ligand binding domain of the murine PPARbeta gene. Homozygous PPARbeta-null term fetuses were smaller than controls, and this phenotype persisted postnatally. Gonadal adipose stores were smaller, and constitutive mRNA levels of CD36 were higher, in PPARbeta-null mice than in controls. In the brain, myelination of the corpus callosum was altered in PPARbeta-null mice. PPARbeta was not required for induction of mRNAs involved in epidermal differentiation induced by O-tetradecanoylphorbol-13-acetate (TPA). The hyperplastic response observed in the epidermis after TPA application was significantly greater in the PPARbeta-null mice than in controls. Inflammation induced by TPA in the skin was lower in wild-type mice fed sulindac than in similarly treated PPARbeta-null mice. These results are the first to provide in vivo evidence of significant roles for PPARbeta in development, myelination of the corpus callosum, lipid metabolism, and epidermal cell proliferation.

Structural interventions to encourage primary HIV prevention among people living with HIV

This analysis focuses on primary prevention for people living with HIV and the importance of actively involving HIV-infected people in developing prevention strategies. Structural-level or policy interventions--as opposed to behavioral or psychological interventions--help shape the world in which HIV-infected people live. Thus, we assess potential policy-level interventions that may serve either as a barrier to or a facilitator of primary HIV prevention from the perspective of the people living with HIV. Among potential barriers, we discuss criminalization of nondisclosure in specific sexual situations, laws limiting travel and immigration, name-based HIV reporting and mandatory partner notification. Under potential facilitators, we discuss confidentiality laws, antidiscrimination protections, expansion of HIV primary care, and primary prevention programs designed to actively involve infected people. Ultimately, whether any given policy is a 'barrier' or 'facilitator' of primary HIV prevention is an empirical question, dependent on the acceptability of an intervention to those already infected and those at risk, thus policy research evaluating the impact of structural factors on people living with HIV is encouraged.

Lack of obesity and normal response to fasting and thyroid hormone in mice lacking uncoupling protein-3

Uncoupling protein-3 (UCP3) is a mitochondrial protein that can diminish the mitochondrial membrane potential. Levels of muscle Ucp3 mRNA are increased by thyroid hormone and fasting. Ucp3 has been proposed to influence metabolic efficiency and is a candidate obesity gene. We have produced a Ucp3 knockout mouse to test these hypotheses. The Ucp3 (-/-) mice had no detectable immunoreactive UCP3 by Western blotting. In mitochondria from the knockout mice, proton leak was greatly reduced in muscle, minimally reduced in brown fat, and not reduced at all in liver. These data suggest that UCP3 accounts for much of the proton leak in skeletal muscle. Despite the lack of UCP3, no consistent phenotypic abnormality was observed. The knockout mice were not obese and had normal serum insulin, triglyceride, and leptin levels, with a tendency toward reduced free fatty acids and glucose. Knockout mice showed a normal circadian rhythm in body temperature and motor activity and had normal body temperature responses to fasting, stress, thyroid hormone, and cold exposure. The base-line metabolic rate and respiratory exchange ratio were the same in knockout and control mice, as were the effects of fasting, a beta3-adrenergic agonist (CL316243), and thyroid hormone on these parameters. The phenotype of Ucp1/Ucp3 double knockout mice was indistinguishable from Ucp1 single knockout mice. These data suggest that Ucp3 is not a major determinant of metabolic rate but, rather, has other functions.

Incidence and outcome of bleeding before the 20th week of pregnancy: prospective study from general practice

OBJECTIVE

To estimate the miscarriage rate in a cohort of pregnant women and the final outcome of pregnancy.

DESIGN

Two year prospective community study.

SETTING

Women registered with four semirural practices at one health centre.

SUBJECTS

626 pregnant women from a population 21448, 5140 of whom were women aged 15-44 years.

MAIN OUTCOME MEASURES

Vaginal bleeding and outcome of pregnancy.

RESULTS

76 of the 89 women with an unwanted pregnancy requested a termination. In the 550 ongoing pregnancies bleeding occurred before the 20th week in 117 (21%), and 67 (12%) ended in miscarriage. The risk of miscarriage was not significantly increased after a miscarriage in the previous pregnancy (11 (15%) women had miscarriage v 55 (12%) women who had not had miscarriage) who had previously had a live birth). Of the 117 women with bleeding, 64 were not admitted to hospital by the general practitioner; 42 of these women had an ultrasound examination at the health centre and 19 subsequently miscarried at home. In hospital 41 of 46 women who miscarried had evacuation of the uterus.

CONCLUSIONS

Bleeding occurred in one fifth of recognised pregnancies before the 20th week and over half of these miscarried. Treatment of women with miscarriage at home means current statistics on miscarriage in Britain are missing many cases.

Endotracheal suction for adult, non-head-injured, patients. A review of the literature

The procedure for endotracheal suctioning was perceived as a problem by the members of a quality circle in the intensive care unit (ICU). Endotracheal suction, when performed in the unit, appeared to be carried out according to the nurses' experience and expertise, and had no formal research backing. An extensive literature search was undertaken, and a framework for endotracheal suction was formulated based on the available evidence. Some of the aspects of endotracheal suction represented in the research evidence appear contradictory, and nurses must make a professional judgement about their suction technique based on the individual circumstances of patients. The wealth of evidence available regarding endotracheal suctioning allows nurses to make an informed decision about care.

Interaction between flavone acetic acid (LM-975, NSC 349512) and radiation in Glasgow's osteogenic sarcoma in vivo

Flavone acetic acid (FAA) is a new anticancer agent in Phase II trials in Europe. In preclinical testing FAA showed broad activity against murine solid tumors and minimal activity against murine leukemias. Our interest in studying the combination of FAA and radiation was based on two of its biological effects which might modify radiation damage. First, FAA depletes ATP and inhibits macromolecular synthesis which are needed to repair radiation-induced DNA strand breaks; and second, inhibition of tumor blood flow by FAA could lead to radiobiological hypoxia. Various schedules of FAA (170 mg/kg I.V.) (n = 9, SF = 0.44) and radiation (10 Gy) (n = 9, SF = 0.37) were investigated against s.c. implanted Glasgow osteogenic sarcoma. In the same model we studied both the kinetics of ATP depletion by 31P-Nuclear Magnetic Resonance Spectroscopy and the repair of radiation induced single and double strand breaks by alkaline elution. The combined response was not significantly different from log-additive when radiation was given 24, 5 or 1 hr before FAA. When FAA was given immediately before radiation an increase in tumor response, significantly different from log-additive (p = 0.03) was observed. This enhancement disappeared when radiation was delayed for between 1 and 48 hr after FAA. While decreased ATP levels and increased response to radiation occurred within minutes after FAA administration, no effect of FAA at either 180 or 200 mg/kg was observed on the repair of radiation induced single or double strand breaks (10 and 50 Gy, respectively; 5 hr after FAA) in spite of significant ATP depletion in the tumors.

Carol Everett on an insider's perspective of the abortion industry. Interview by Andrew Alatis

Carol Everett was involved in the abortion industry in the Dallas-Ft. Worth, Texas, area from 1977 until 1983. As director of four clinics and owner of two, Ms. Everett was responsible for the clinic's daily operation as well as for all employee training programs. Ms. Everett, who had an abortion soon after the Roe v. Wade decision in 1973, now describes the abortion industry from an insider's perspective.

Discrepancy between cytotoxicity and DNA interstrand crosslinking of carboplatin and cisplatin in vivo

We used the method of alkaline elution to compare quantitatively the DNA lesions produced by cisplatin and carboplatin in the AKR leukemia in vivo. These data were compared with cytotoxicity of each drug in the same animal model and in a solid tumor murine model (colon 26). DNA-protein and DNA-DNA interstrand crosslinks were formed in similar proportions by both drugs when peak values of crosslinking were compared. No clear difference in the rate of formation of both types of crosslinks could be observed between these drugs. On a molar basis a 3- to 4-fold more carboplatin had to be given to obtain equivalent frequencies of both types of crosslinks. In contrast, to obtain equitoxicity in the same animal tumor model, 13 fold higher doses of carboplatin had to be given. This difference in cytotoxicity between both drugs is comparable to the difference measured in colon 26 in vivo (16 fold). Both values are in the range of literature data (10-25 fold) dealing with the relative potency of cisplatin and carboplatin in murine tumor models.

In vivo DNA cross-linking by cyclophosphamide: comparison of human chronic lymphatic leukemia cells with mouse L1210 leukemia and normal bone marrow cells

Alkaline elution was done on a variety of cells following cyclophosphamide (CY) treatment in vivo. Cells used were L1210 leukemia, normal mouse bone marrow, and peripheral blood cells obtained from a patient with chronic lymphatic leukemia (CLL). Endpoints used were determination of single strand breaks, DNA-DNA interstrand and DNA-protein cross-links. After treatment of mice with CY (4 mg/mouse), low levels of single strand breaks were observed in both L1210 leukemia and CDF1 normal bone marrow. When a patient with CLL was treated with CY (750 mg/m2), no evidence of single strand breaks could be demonstrated. Maximum levels of DNA-DNA interstrand cross-links were observed in mice 2 h after injection of CY for the L1210 leukemia cells [175 +/- 25 rad-equivalents (req)] and at 4 h for the CDF1 normal bone marrow cells (47 +/- 9 req). In human CLL, maximum levels were observed 12 h after injection of CY. Peak levels of DNA-DNA interstrand cross-links were approximately 4-fold lower in CDF1 normal bone marrow cells than in L1210 leukemia. The frequencies measured in human CLL cells were relatively low at any timepoint (mean at 12 h = 36 req). Maximum levels of DNA-protein cross-links were observed 4 h after injection of CY (4 mg/mouse) for both L1210 leukemia [123 req (mean)] and normal bone marrow cells [50 req (mean)]. DNA-protein cross-links were measurable in CLL at timepoints later than 4 h after the start of injection of CY. In order to obtain equitoxicity between L1210 leukemia and CDF1 normal bone marrow cells, about 18-fold higher doses of CY had to be given than in the case of the normal bone marrow cells. In contrast, only 4-fold higher doses had to be given to the normal bone marrow to obtain equivalent peak levels of DNA-DNA interstrand cross-links.

Reported management of threatened miscarriage by general practitioners in Wessex

Questionnaires were sent to all 1432 general practitioners in the Wessex region to obtain information about their current management of bleeding in early pregnancy. A total of 1290 (90%) returned completed questionnaires. These showed widely varying views about the prognostic importance of particular symptoms and physical signs and about elements of management. Although 96% of the respondents prescribed bed rest more or less routinely for heavy bleeding in early pregnancy, only 17% felt it was mandatory, and 32% admitted that they did not believe it affected the outcome. Of the 13% of respondents who prescribed progestogens for threatened miscarriage, most did so on the advice of their local obstetrician. Seventeen per cent of the doctors always admitted women with apparently complete miscarriages to hospital. Twenty nine per cent of the respondents never gave anti-D immunoglobulin to rhesus negative women after a complete miscarriage. Bleeding in early pregnancy is a common problem and more research is required to improve management, particularly the assessment of fetal viability.

Intramural esophageal hamartoma: a report of two cases and review of the literature

Intramural esophageal hamartoma is an unusual cause of distal esophageal obstruction in childhood. Two cases are reported with a review of the literature.