STAT1 Pathway Mediates Amplification of Metastatic Potential and Resistance to Therapy

BACKGROUND: Traditionally IFN/STAT1 signaling is connected with an anti-viral response and pro-apoptotic tumor-suppressor functions. Emerging functions of a constitutively activated IFN/STAT1 pathway suggest an association with an aggressive tumor phenotype. We hypothesized that tumor clones that constitutively overexpress this pathway are preferentially selected by the host microenvironment due to a resistance to STAT1-dependent cytotoxicity and demonstrate increased metastatic ability combined with increased resistance to genotoxic stress. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that clones of B16F1 tumors grown in the lungs of syngeneic C57BL/6 mice demonstrate variable transcriptional levels of IFN/STAT1 pathway expression. Tumor cells that constitutively overexpress the IFN/STAT1 pathway (STAT1(H) genotype) are selected by the lung microenvironment. STAT1(H) tumor cells also demonstrate resistance to IFN-gamma (IFNgamma), ionizing radiation (IR), and doxorubicin relative to parental B16F1 and low expressors of the IFN/STAT1 pathway (STAT1(L) genotype). Stable knockdown of STAT1 reversed the aggressive phenotype and decreased both lung colonization and resistance to genotoxic stress. CONCLUSIONS: Our results identify a pathway activated by tumor-stromal interactions thereby selecting for pro-metastatic and therapy-resistant tumor clones. New therapies targeted against the IFN/STAT1 signaling pathway may provide an effective strategy to treat or sensitize aggressive tumor clones to conventional cancer therapies and potentially prevent distant organ colonization

STAT1-dependent expression of energy metabolic pathways links tumour growth and radioresistance to the Warburg effect

<p>Abstract</p> <p>Background</p> <p>The Signal Transducer and Activator of Transcription 1 (STAT1) has traditionally been regarded as a transmitter of interferon signaling and a pro-apoptotic tumour suppressor. Recent data have identified new functions of STAT1 associated with tumourigenesis and resistance to genotoxic stress, including ionizing radiation (IR) and chemotherapy. To investigate the mechanisms contributing to the tumourigenic functions of STAT1, we performed a combined transcriptomic-proteomic expressional analysis and found that STAT1 is associated with regulation of energy metabolism with potential implication in the Warburg effect.</p> <p>Methods</p> <p>We generated a stable knockdown of STAT1 in the SCC61 human squamous cell carcinoma cell line, established tumour xenografts in athymic mice, and compared transcriptomic and proteomic profiles of STAT1 wild-type (WT) and knockdown (KD) untreated or irradiated (IR) tumours. Transcriptional profiling was based on Affymetrix Human GeneChip^®Gene 1.0 ST microarrays. Proteomes were determined from the tandem mass spectrometry (MS/MS) data by searching against the human subset of the UniProt database. Data were analysed using Significance Analysis of Microarrays for ribonucleic acid and Visualize software for proteins. Functional analysis was performed with Ingenuity Pathway Analysis with statistical significance measured by Fisher's exact test.</p> <p>Results</p> <p>Knockdown of STAT1 led to significant growth suppression in untreated tumours and radio sensitization of irradiated tumours. These changes were accompanied by alterations in the expression of genes and proteins of glycolysis/gluconeogenesis (GG), the citrate cycle (CC) and oxidative phosphorylation (OP). Of these pathways, GG had the most concordant changes in gene and protein expression and demonstrated a STAT1-dependent expression of genes and proteins consistent with tumour-specific glycolysis. In addition, IR drastically suppressed the GG pathway in STAT1 KD tumours without significant change in STAT1 WT tumours.</p> <p>Conclusion</p> <p>Our results identify a previously uncharacterized function of STAT1 in tumours: expressional regulation of genes encoding proteins involved in glycolysis, the citrate cycle and mitochondrial oxidative phosphorylation, with predominant regulation of glycolytic genes. STAT1-dependent expressional regulation of glycolysis suggests a potential role for STAT1 as a transcriptional modulator of genes responsible for the Warburg effect.</p

Extracellular matrix hydrogels from decellularized tissues: structure and function

Extracellular matrix (ECM) bioscaffolds prepared from decellularized tissues have been used to facilitate constructive and functional tissue remodeling in a variety of clinical applications. The discovery that these ECM materials could be solubilized and subsequently manipulated to form hydrogels expanded their potential in vitro and in vivo utility; i.e. as culture substrates comparable to collagen or Matrigel, and as injectable materials that fill irregularly-shaped defects. The mechanisms by which ECM hydrogels direct cell behavior and influence remodeling outcomes are only partially understood, but likely include structural and biological signals retained from the native source tissue. The present review describes the utility, formation, and physical and biological characterization of ECM hydrogels. Two examples of clinical application are presented to demonstrate in vivo utility of ECM hydrogels in different organ systems. Finally, new research directions and clinical translation of ECM hydrogels are discusse

Obeticholic acid for the treatment of non-alcoholic steatohepatitis: interim analysis from a multicentre, randomised, placebo-controlled phase 3 trial

Background Non-alcoholic steatohepatitis (NASH) is a common type of chronic liver disease that can lead to cirrhosis. Obeticholic acid, a farnesoid X receptor agonist, has been shown to improve the histological features of NASH. Here we report results from a planned interim analysis of an ongoing, phase 3 study of obeticholic acid for NASH. Methods In this multicentre, randomised, double-blind, placebo-controlled study, adult patients with definite NASH,non-alcoholic fatty liver disease (NAFLD) activity score of at least 4, and fibrosis stages F2–F3, or F1 with at least oneaccompanying comorbidity, were randomly assigned using an interactive web response system in a 1:1:1 ratio to receive oral placebo, obeticholic acid 10 mg, or obeticholic acid 25 mg daily. Patients were excluded if cirrhosis, other chronic liver disease, elevated alcohol consumption, or confounding conditions were present. The primary endpointsfor the month-18 interim analysis were fibrosis improvement (≥1 stage) with no worsening of NASH, or NASH resolution with no worsening of fibrosis, with the study considered successful if either primary endpoint was met. Primary analyses were done by intention to treat, in patients with fibrosis stage F2–F3 who received at least one dose of treatment and reached, or would have reached, the month 18 visit by the prespecified interim analysis cutoff date. The study also evaluated other histological and biochemical markers of NASH and fibrosis, and safety. This study is ongoing, and registered with ClinicalTrials.gov, NCT02548351, and EudraCT, 20150-025601-6. Findings Between Dec 9, 2015, and Oct 26, 2018, 1968 patients with stage F1–F3 fibrosis were enrolled and received at least one dose of study treatment; 931 patients with stage F2–F3 fibrosis were included in the primary analysis (311 in the placebo group, 312 in the obeticholic acid 10 mg group, and 308 in the obeticholic acid 25 mg group). The fibrosis improvement endpoint was achieved by 37 (12%) patients in the placebo group, 55 (18%) in the obeticholic acid 10 mg group (p=0·045), and 71 (23%) in the obeticholic acid 25 mg group (p=0·0002). The NASH resolution endpoint was not met (25 [8%] patients in the placebo group, 35 [11%] in the obeticholic acid 10 mg group [p=0·18], and 36 [12%] in the obeticholic acid 25 mg group [p=0·13]). In the safety population (1968 patients with fibrosis stages F1–F3), the most common adverse event was pruritus (123 [19%] in the placebo group, 183 [28%] in the obeticholic acid 10 mg group, and 336 [51%] in the obeticholic acid 25 mg group); incidence was generally mild to moderate in severity. The overall safety profile was similar to that in previous studies, and incidence of serious adverse events was similar across treatment groups (75 [11%] patients in the placebo group, 72 [11%] in the obeticholic acid 10 mg group, and 93 [14%] in the obeticholic acid 25 mg group). Interpretation Obeticholic acid 25 mg significantly improved fibrosis and key components of NASH disease activity among patients with NASH. The results from this planned interim analysis show clinically significant histological improvement that is reasonably likely to predict clinical benefit. This study is ongoing to assess clinical outcomes

Race, ethnicity, and melanocortin-1-receptor polymorphisms are associated with post-burn hypertrophic scarring: a prospective cohort study

Thesis (Master's)--University of Washington, 2015Objective: To assess the association between melanocortin 1 receptor (MC1R) single-nucleotide polymorphisms (SNPs) and severity of post-burn hypertrophic scarring (HTS). Background: People of color seem predisposed to HTS, but this association has not been quantified, nor have genetic factors been identified. Recent evidence indicates that melanocortin signaling has an anti-inflammatory effect, and MC1R loss-of-function is associated with fibrogenesis. Methods: Between 2007 and 2013 we prospectively enrolled adults admitted with deep burns and obtained blood for DNA isolation. Subjects were evaluated over time using the Vancouver Scar Scale (VSS) and asked to rate their itching. Genotyping was performed for 8 MC1R SNPs. Testing for association with severe HTS (VSS>7) and itch severity (0-10) was based on multivariate regression with adjustment for known HTS risk factors. Results: Of 425 subjects, (median burn size 6.8% body surface area), 77% were White and 88% were non-Hispanic. The prevalence of severe HTS (VSS>7) was 49%, and the mean itch score was 3.9. In multivariate analysis, Hispanic ethnicity (prevalence ratio [PR] 1.32) and Asian (PR 1.61), Black/African American (PR 1.95), and Native American (PR 1.84) race were independently associated with severe HTS. Two MC1R SNPs, R151C (P = 0.033) and R163Q (P = 0.005), were significantly associated with severe HTS. Hispanic ethnicity and Asian race were associated with increased pruritus, and MC1R T314T was associated with decreased pruritus. Conclusions: Race and ethnicity are significantly associated with post-burn HTS and itch severity, and MC1R R151C and R163Q are the first SNPs to be associated with post-burn HTS

Missense Variant in MAPK Inactivator PTPN5 Is Associated with Decreased Severity of Post-Burn Hypertrophic Scarring.

BACKGROUND:Hypertrophic scarring (HTS) is hypothesized to have a genetic mechanism, yet its genetic determinants are largely unknown. The mitogen-activated protein kinase (MAPK) pathways are important mediators of inflammatory signaling, and experimental evidence implicates MAPKs in HTS formation. We hypothesized that single-nucleotide polymorphisms (SNPs) in MAPK-pathway genes would be associated with severity of post-burn HTS. METHODS:We analyzed data from a prospective-cohort genome-wide association study of post-burn HTS. We included subjects with deep-partial-thickness burns admitted to our center who provided blood for genotyping and had at least one Vancouver Scar Scale (VSS) assessment. After adjusting for HTS risk factors and population stratification, we tested MAPK-pathway gene SNPs for association with the four VSS variables in a joint regression model. In addition to individual-SNP analysis, we performed gene-based association testing. RESULTS:Our study population consisted of 538 adults (median age 40 years) who were predominantly White (76%) males (71%) admitted to our center from 2007-2014 with small-to-moderate-sized burns (median burn size 6% total body surface area). Of 2,146 SNPs tested, a rare missense variant in the PTPN5 gene (rs56234898; minor allele frequency 1.5%) was significantly associated with decreased severity of post-burn HTS (P = 1.3×10-6). In gene-based analysis, PTPN5 (P = 1.2×10-5) showed a significant association and BDNF (P = 9.5×10-4) a borderline-significant association with HTS severity. CONCLUSIONS:We report PTPN5 as a novel genetic locus associated with HTS severity. PTPN5 is a MAPK inhibitor expressed in neurons, suggesting a potential role for neurotrophic factors and neuroinflammatory signaling in HTS pathophysiology

Manhattan plot of <i>P</i> values for MAPK-pathway SNP association testing with severity of post-burn scarring.

<p>The dashed line corresponds to the analysis-wide significance threshold (<i>P</i> = 2×10⁻⁵). No chromosome 18 or 21 SNPs are shown because none of the KEGG MAPK pathway genes are located on those chromosomes.</p

Quantile-quantile plot of <i>P</i> values from association testing of MAPK-pathway gene SNPs with severity of post-burn scarring.

<p>The solid line indicates the expected null distribution.</p

The Vancouver Scar Scale [20].

<p>The Vancouver Scar Scale [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0149206#pone.0149206.ref020" target="_blank">20</a>].</p

Surgery for lower extremity symptomatic neuroma: Long-term outcomes

Introduction: Traumatic neuroma caused by injuries or surgery can result in neuropathic pain, functional impairment, and psychological distress, which has an impact on quality of life. The aim of this study was to identify the factors related to successful treatment of symptomatic lower extremity symptomatic neuromas using patient-reported outcome measures (PROMs). Methods: Thirty-two patients with 48 symptomatic neuromas completed the PROMIS mobility, PROMIS pain interference (PI), Numeric Rating Scale (NRS) for pain (0–10) for both pre- and post-operative pain, and the PROMIS depression at a mean of 8.9±4.5 years following neuroma surgery. Neuromas were located around the foot and ankle (n=18, 38%), leg (n=14, 29%), around the knee (n=13, 27%), and in the thigh (n=3, 6.3%). Surgical treatment included neuroma excision and implantation (n=29, 60%) followed by neuroma excision alone or excision with placement in the subcutaneous tissue (n=12, 25%). We performed multivariable analysis to identify the factors influencing the PROMs. Results: Patients reported significant reduction in mean NRS pain after surgery (7.3 vs 4.9, p=0.0013). Higher PROMIS depression scores were independently associated with inferior PROMIS mobility scores (β=–0.38, p=0.001), higher PROMIS PI scores (β=0.68, p<0.001), and higher NRS pain scores (β=0.1, p=0.001). Additionally, smoking was independently associated with higher NRS pain scores (β=1.59, p=0.049) Conclusion: Surgical treatment of symptomatic neuromas of the lower extremity provides a long-term improvement in 59% of patients, but 19% of patients still reported severe persistent pain despite surgical treatment. Smoking and negative mood have negative effects on patient-reported outcomes after neuroma surgery