104 research outputs found
The initiator methionine tRNA drives secretion of type II collagen from stromal fibroblasts to promote tumor growth and angiogenesis
Summary:
Expression of the initiator methionine tRNA (tRNAi
Met)
is deregulated in cancer. Despite this fact, it is not
currently known how tRNAi
Met expression levels influence
tumor progression. We have found that tRNAi
Met
expression is increased in carcinoma-associated
fibroblasts, implicating deregulated expression of
tRNAi
Met in the tumor stroma as a possible contributor
to tumor progression. To investigate how elevated
stromal tRNAi
Met contributes to tumor progression,
we generated a mouse expressing additional copies
of the tRNAi
Met gene (2+tRNAi
Met mouse). Growth
and vascularization of subcutaneous tumor allografts
was enhanced in 2+tRNAi
Met mice compared with
wild-type littermate controls. Extracellular matrix
(ECM) deposited by fibroblasts from 2+tRNAi
Met
mice supported enhanced endothelial cell and fibroblast
migration. SILAC mass spectrometry indicated
that elevated expression of tRNAi
Met significantly
increased synthesis and secretion of certain types of
collagen, in particular type II collagen. Suppression
of type II collagen opposed the ability of tRNAi
Metoverexpressing
fibroblasts to deposit pro-migratory
ECM. We used the prolyl hydroxylase inhibitor ethyl-
3,4-dihydroxybenzoate (DHB) to determine whether
collagen synthesis contributes to the tRNAi
Met-driven
pro-tumorigenic stroma in vivo. DHB had no effect
on the growth of syngeneic allografts in wild-type
mice but opposed the ability of 2+tRNAi
Met mice to
support increased angiogenesis and tumor growth.
Finally, collagen II expression predicts poor prognosis
in high-grade serous ovarian carcinoma. Taken
together, these data indicate that increased tRNAi
Met
levels contribute to tumor progression by enhancing
the ability of stromal fibroblasts to synthesize and
secrete a type II collagen-rich ECM that supports
endothelial cell migration and angiogenesis
Interpreting ambiguous ‘trace’ results in Schistosoma mansoni CCA Tests: Estimating sensitivity and specificity of ambiguous results with no gold standard
Background The development of new diagnostics is an important tool in the fight against disease. Latent Class Analysis (LCA) is used to estimate the sensitivity and specificity of tests in the absence of a gold standard. The main field diagnostic for Schistosoma mansoni infection, Kato-Katz (KK), is not very sensitive at low infection intensities. A point-of-care circulating cathodic antigen (CCA) test has been shown to be more sensitive than KK. However, CCA can return an ambiguous ‘trace’ result between ‘positive’ and ‘negative’, and much debate has focused on interpretation of traces results. Methodology/Principle findings We show how LCA can be extended to include ambiguous trace results and analyse S. mansoni studies from both Côte d’Ivoire (CdI) and Uganda. We compare the diagnostic performance of KK and CCA and the observed results by each test to the estimated infection prevalence in the population. Prevalence by KK was higher in CdI (13.4%) than in Uganda (6.1%), but prevalence by CCA was similar between countries, both when trace was assumed to be negative (CCAtn: 11.7% in CdI and 9.7% in Uganda) and positive (CCAtp: 20.1% in CdI and 22.5% in Uganda). The estimated sensitivity of CCA was more consistent between countries than the estimated sensitivity of KK, and estimated infection prevalence did not significantly differ between CdI (20.5%) and Uganda (19.1%). The prevalence by CCA with trace as positive did not differ significantly from estimates of infection prevalence in either country, whereas both KK and CCA with trace as negative significantly underestimated infection prevalence in both countries. Conclusions Incorporation of ambiguous results into an LCA enables the effect of different treatment thresholds to be directly assessed and is applicable in many fields. Our results showed that CCA with trace as positive most accurately estimated infection prevalence
Preclinical Evidence That Trametinib Enhances the Response to Antiangiogenic Tyrosine Kinase Inhibitors in Renal Cell Carcinoma.
Sunitinib and pazopanib are antiangiogenic tyrosine kinase inhibitors (TKI) used to treat metastatic renal cell carcinoma (RCC). However, the ability of these drugs to extend progression-free and overall survival in this patient population is limited by drug resistance. It is possible that treatment outcomes in RCC patients could be improved by rationally combining TKIs with other agents. Here, we address whether inhibition of the Ras-Raf-MEK-ERK1/2 pathway is a rational means to improve the response to TKIs in RCC. Using a xenograft model of RCC, we found that tumors that are resistant to sunitinib have a significantly increased angiogenic response compared with tumors that are sensitive to sunitinib in vivo. We also observed significantly increased levels of phosphorylated ERK1/2 in the vasculature of resistant tumors, when compared with sensitive tumors. These data suggested that the Ras-Raf-MEK-ERK1/2 pathway, an important driver of angiogenesis in endothelial cells, remains active in the vasculature of TKI-resistant tumors. Using an in vitro angiogenesis assay, we identified that the MEK inhibitor (MEKI) trametinib has potent antiangiogenic activity. We then show that, when trametinib is combined with a TKI in vivo, more effective suppression of tumor growth and tumor angiogenesis is achieved than when either drug is utilized alone. In conclusion, we provide preclinical evidence that combining a TKI, such as sunitinib or pazopanib, with a MEKI, such as trametinib, is a rational and efficacious treatment regimen for RCC
Having a creative day:understanding entrepreneurs’ daily idea generation through a recovery lens
Prior research has shown that trait creativity is important for becoming an entrepreneur and successful in business. We explore a new perspective by investigating how recovery from work stress influences entrepreneurs’ daily idea generation, a key aspect of creativity. Physio-logical and mental recovery enables the cognitive processes of creative problem-solving. Moreover, differences in mental recovery processes help to explain age-related changes in en-trepreneurs’ creativity. Multilevel analyses based on 415 daily data from 62 entrepreneurs support our predictions. Our study introduces a new “state” perspective to understanding en-trepreneurs’ creativity, and highlights the critical role of recovery processes for idea genera-tion
Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers
Introduction: More than 70 common alleles are known to be involved in breast cancer (BC) susceptibility, and several exhibit significant heterogeneity in their associations with different BC subtypes. Although there are differences in the association patterns between BRCA1 and BRCA2 mutation carriers and the general population for several loci, no study has comprehensively evaluated the associations of all known BC susceptibility alleles with risk of BC subtypes in BRCA1 and BRCA2 carriers. Methods: We used data from 15,252 BRCA1 and 8,211 BRCA2 carriers to analyze the associations between approximately 200,000 genetic variants on the iCOGS array and risk of BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and triple-negative- (TN) status; morphologic subtypes; histological grade; and nodal involvement. Results: The estimated BC hazard ratios (HRs) for the 74 known BC alleles in BRCA1 carriers exhibited moderate correlations with the corresponding odds ratios from the general population. However, their associations with ER-positive BC in BRCA1 carriers were more consistent with the ER-positive as
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
The role of Ephrin B2 in blood vessel development
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
An institutional explanation for the mortality of contractually-based new firms
Research Paper Series (National University of Singapore. Faculty of Business Administration); 1997-0391-3
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